Bump version to 3.2.2

The prune command can remove redundant chunks (chunks with the same chunk id
but at different subdirectory level).  However, if the same chunk appears
mutliple times in the listing returned by the storage, it will be treated as
a redundant chunk and thus removed.

.github/ISSUE_TEMPLATE.md

@@ -0,0 +1,17 @@
+---
+name: Please use the official forum
+about: Please use the official forum instead of Github
+title: 'Please use the official forum'
+labels: ''
+assignees: ''
+
+---
+
+
+Please **use the [Duplicacy Forum](https://forum.duplicacy.com/)** when reporting bugs, making feature requests, asking for help or simply praising Duplicacy for its ease of use.
+
+We strongly encourage you to create an account on the forum and use that platform for discussion as there is a higher chance that someone there will talk to you. 
+
+There is a handful of people watching the Github Issues and we are in the process of moving **all** of them to the forum as well. Most likely you will not receive an answer here or it will be very slow and you will be pointed to the forum.
+
+We have already created a comprehensive [Guide](https://forum.duplicacy.com/t/duplicacy-user-guide/1197), and a [How-To](https://forum.duplicacy.com/c/how-to) category which stores more wisdom than these issues on Github.

.gitignore

@@ -1,3 +0,0 @@
-.idea
-duplicacy_main
-

ACKNOWLEDGEMENTS.md

@@ -14,3 +14,4 @@ Duplicacy is based on the following open source projects:
 |https://github.com/pcwizz/xattr            |  BSD-2-Clause |
 |https://github.com/minio/blake2b-simd      |  Apache-2.0 |
 |https://github.com/go-ole/go-ole           |  MIT |
+https://github.com/ncw/swift                |  MIT |

DESIGN.md

@@ -1,215 +1,5 @@
-## Lock-Free Deduplication
-
-The three elements of lock-free deduplication are:
-
-* Use variable-size chunking algorithm to split files into chunks
-* Store each chunk in the storage using a file name derived from its hash, and rely on the file system API to manage chunks without using a centralized indexing database
-* Apply a *two-step fossil collection* algorithm to remove chunks that become unreferenced after a backup is deleted
-
-The variable-size chunking algorithm, also called Content-Defined Chunking, is well-known and has been adopted by many
-backup tools. The main advantage of the variable-size chunking algorithm over the fixed-size chunking algorithm (as used
-by rsync) is that in the former the rolling hash is only used to search for boundaries between chunks, after which a far
-more collision-resistant hash function like MD5 or SHA256 is applied on each chunk. In contrast, in the fixed-size
-chunking algorithm, for the purpose of detecting inserts or deletions, a lookup in the known hash table is required every
-time the rolling hash window is shifted by one byte, thus significantly reducing the chunk splitting performance.
-
-What is novel about lock-free deduplication is the absence of a centralized indexing database for tracking all existing
-chunks and for determining which chunks are not needed any more.  Instead, to check if a chunk has already been uploaded
-before, one can just perform a file lookup via the file storage API using the file name derived from the hash of the chunk.
-This effectively turns a cloud storage offering only a very limited
-set of basic file operations into a powerful modern backup backend capable of both block-level and file-level deduplication.  More importantly, the absence of a centralized indexing database means that there is no need to implement a distributed locking mechanism on top of the file storage.
-
-By eliminating the chunk indexing database, lock-free duplication not only reduces the code complexity but also makes the deduplication less error-prone.  Each chunk is saved individually in its own file, and once saved there is no need for modification.  Data corruption is therefore less likely to occur because of the immutability of chunk files.  Another benefit that comes naturally from lock-free duplication is that when one client creates a new chunk, other clients that happen to have the same original file will notice that the chunk  already exist and therefore will not upload the same chunk again.  This pushes the deduplication to its highest level -- clients without knowledge of each other can share identical chunks with no extra effort.
-
-There is one problem, though.
-Deletion of snapshots without an indexing database, when concurrent access is permitted, turns out to be a hard problem.
-If exclusive access to a file storage by a single client can be guaranteed, the deletion procedure can simply search for
-chunks not referenced by any backup and delete them. However, if concurrent access is required, an unreferenced chunk
-can't be trivially removed, because of the possibility that a backup procedure in progress may reference the same chunk.
-The ongoing backup procedure, still unknown to the deletion procedure, may have already encountered that chunk during its
-file scanning phase, but decided not to upload the chunk again since it already exists in the file storage. 
-
-Fortunately, there is a solution to address the deletion problem and make lock-free deduplication practical.  The solution is a *two-step fossil collection* algorithm that deletes unreferenced chunks in two steps: identify and collect them in the first step, and then permanently remove them once certain conditions are met.
-
-## Two-Step Fossil Collection
-
-Interestingly, the two-step fossil collection algorithm hinges on a basic file operation supported almost universally, *file renaming*.
-When the deletion procedure identifies a chunk not referenced by any known snapshots, instead of deleting the chunk file
-immediately, it changes the name of the chunk file (and possibly moves it to a different directory).
-A chunk that has been renamed is called a *fossil*.
-
-The fossil still exists in the file storage.  Two rules are enforced regarding the access of fossils:
-
-* A restore, list, or check procedure that reads existing backups can read the fossil if the original chunk cannot be found.
-* A backup procedure does not check the existence of a fossil. That is, it must upload a chunk if it cannot find the chunk, even if an equivalent fossil exists.
-
-In the first step of the deletion procedure, called the *fossil collection* step, the names of all identified fossils will
-be saved in a fossil collection file. The deletion procedure then exits without performing further actions. This step has not effectively changed any chunk references due to the first fossil access rule.  If a backup procedure references a chunk after it is marked as a fossil, a new chunk will be uploaded because of the second fossil access rule, as shown in Figure 1.
-
-<p align="center">
-  <img src="https://github.com/gilbertchen/duplicacy-beta/blob/master/images/fossil_collection_1.png?raw=true" 
-       alt="Reference after Rename"/>
-</p>
-
-The second step, called the *fossil deletion* step, will permanently delete fossils, but only when two conditions are met:
-
-* For each snapshot id, there is a new snapshot that was not seen by the fossil collection step
-* The new snapshot must finish after the fossil collection step
-
-The first condition guarantees that if a backup procedure references a chunk before the deletion procedure turns it into a fossil, the reference will be detected in the fossil deletion step which will then turn the fossil back into a normal chunk.
-
-The second condition guarantees that any backup procedure unknown to the fossil deletion step can start only after the fossil collection step finishes.  Therefore, if it references a chunk that was identified as fossil in the fossil collection step, it should observe the fossil, not the chunk, so it will upload a new chunk, according to the second fossil access rule.
-
-Therefore, if a backup procedure references a chunk before the chunk is marked a fossil, the fossil deletion step will not
-delete the chunk until it sees that backup procedure finishes (as indicated by the appearance of a new snapshot file uploaded to the storage).  This ensures that scenarios depicted in Figure 2 will never happen.
-
-<p align="center">
-  <img src="https://github.com/gilbertchen/duplicacy-beta/blob/master/images/fossil_collection_2.png?raw=true" 
-       alt="Reference before Rename"/>
-</p>
-
-
-## Snapshot Format
-
-A snapshot file is a file that the backup procedure uploads to the file storage after it finishes splitting files into
-chunks and uploading all new chunks. It mainly contains metadata for the backup overall, metadata for all the files,
-and chunk references for each file. Here is an example snapshot file for a repository containing 3 files (file1, file2,
-and dir1/file3):
-
-```json
-{
-  "id": "host1",
-  "revision": 1,
-  "tag": "first",
-  "start_time": 1455590487,
-  "end_time": 1455590487,
-  "files": [
-    {
-      "path": "file1",
-      "content": "0:0:2:6108",
-      "hash": "a533c0398194f93b90bd945381ea4f2adb0ad50bd99fd3585b9ec809da395b51",
-      "size": 151901,
-      "time": 1455590487,
-      "mode": 420
-    },
-    {
-      "path": "file2",
-      "content": "2:6108:3:7586",
-      "hash": "f6111c1562fde4df9c0bafe2cf665778c6e25b49bcab5fec63675571293ed644",
-      "size": 172071,
-      "time": 1455590487,
-      "mode": 420
-    },
-    {
-      "path": "dir1/",
-      "size": 102,
-      "time": 1455590487,
-      "mode": 2147484096
-    },
-    {
-      "path": "dir1/file3",
-      "content": "3:7586:4:1734",
-      "hash": "6bf9150424169006388146908d83d07de413de05d1809884c38011b2a74d9d3f",
-      "size": 118457,
-      "time": 1455590487,
-      "mode": 420
-    }
-  ],
-  "chunks": [
-    "9f25db00881a10a8e7bcaa5a12b2659c2358a579118ea45a73c2582681f12919",
-    "6e903aace6cd05e26212fcec1939bb951611c4179c926351f3b20365ef2c212f",
-    "4b0d017bce5491dbb0558c518734429ec19b8a0d7c616f68ddf1b477916621f7",
-    "41841c98800d3b9faa01b1007d1afaf702000da182df89793c327f88a9aba698",
-    "7c11ee13ea32e9bb21a694c5418658b39e8894bbfecd9344927020a9e3129718"
-  ],
-  "lengths": [
-    64638,
-    81155,
-    170593,
-    124309,
-    1734
-  ] 
-}
-```
-
-When Duplicacy splits a file in chunks using the variable-size chunking algorithm, if the end of a file is reached and yet the boundary marker for terminating a chunk
-hasn't been found, the next file, if there is one, will be read in and the chunking algorithm continues. It is as if all 
-files were packed into a big tar file which is then split into chunks.
-
-The *content* field of a file indicates the indexes of starting and ending chunks and the corresponding offsets. For
-instance, *file1* starts at chunk 0 offset 0 while ends at chunk 2 offset 6108, immediately followed by *file2*.
-
-The backup procedure can run in one of two modes. In the default quick mode, only modified or new files are scanned. Chunks only
-referenced by old files that have been modified are removed from the chunk sequence, and then chunks referenced by new 
-files are appended. Indices for unchanged files need to be updated too.
-
-In the safe mode (enabled by the -hash option), all files are scanned and the chunk sequence is regenerated.
-
-The length sequence stores the lengths for all chunks, which are needed when calculating some statistics such as the total
-length of chunks. For a repository containing a large number of files, the size of the snapshot file can be tremendous. 
-To make the situation worse, every time a big snapshot file would have been uploaded even if only a few files have been changed since
-last backup. To save space, the variable-size chunking algorithm is also applied to the three dynamic fields of a snapshot
-file, *files*, *chunks*, and *lengths*.
-
-Chunks produced during this step are deduplicated and uploaded in the same way as regular file chunks. The final snapshot file
-contains sequences of chunk hashes and other fixed size fields:
-
-```json
-{
-  "id": "host1",
-  "revision": 1,
-  "start_time": 1455590487,
-  "tag": "first",
-  "end_time": 1455590487,
-  "file_sequence": [
-    "21e4c69f3832e32349f653f31f13cefc7c52d52f5f3417ae21f2ef5a479c3437",
-  ],
-  "chunk_sequence": [
-    "8a36ffb8f4959394fd39bba4f4a464545ff3dd6eed642ad4ccaa522253f2d5d6"
-  ],
-  "length_sequence": [
-    "fc2758ae60a441c244dae05f035136e6dd33d3f3a0c5eb4b9025a9bed1d0c328"
-  ]
-}
-```
-
-In the extreme case where the repository has not been modified since last backup, a new backup procedure will not create any new chunks,
-as shown by the following output from a real use case:
-
-```
-$ duplicacy backup -stats
-Storage set to sftp://gchen@192.168.1.100/Duplicacy
-Last backup at revision 260 found
-Backup for /Users/gchen/duplicacy at revision 261 completed
-Files: 42367 total, 2,204M bytes; 0 new, 0 bytes
-File chunks: 447 total, 2,238M bytes; 0 new, 0 bytes, 0 bytes uploaded
-Metadata chunks: 6 total, 11,753K bytes; 0 new, 0 bytes, 0 bytes uploaded
-All chunks: 453 total, 2,249M bytes; 0 new, 0 bytes, 0 bytes uploaded
-Total running time: 00:00:05
-```
-
-## Encryption
-
-When encryption is enabled (by the -e option with the *init* or *add* command), Duplicacy will generate 4 random 256 bit keys:
-
-* *Hash Key*: for generating a chunk hash from the content of a chunk
-* *ID Key*: for generating a chunk id from a chunk hash
-* *Chunk Key*: for encrypting chunk files
-* *File Key*: for encrypting non-chunk files such as snapshot files.
-
-Here is a diagram showing how these keys are used:
-
-<p align="center">
-  <img src="https://github.com/gilbertchen/duplicacy-beta/blob/master/images/duplicacy_encryption.png?raw=true" 
-       alt="encryption"/>
-</p>
-
-Chunk hashes are used internally and stored in the snapshot file.  They are never exposed unless the snapshot file is decrypted.  Chunk ids are used as the file names for the chunks and therefore exposed.  When the *cat* command is used to print out a snapshot file, the chunk hashes stored in the snapshot file will be converted into chunk ids first which are then displayed instead.
-
-Chunk content is encrypted by AES-GCM, with an encryption key that is the HMAC-SHA256 of the chunk Hash with the *Chunk Key* as the secret key.
-
-The snapshot is encrypted by AES-GCM too, using an encrypt key that is the HMAC-SHA256 of the file path with the *File Key* as the secret key.
-
-These four random keys are saved in a file named 'config' in the storage, encrypted with a master key derived from the PBKDF2 function on
-the storage password chosen by the user.
+All documentation has been moved to our wiki page:
 
+* [Lock-Free Deduplication](https://github.com/gilbertchen/duplicacy/wiki/Lock-Free-Deduplication)
+* [Snapshot Format](https://github.com/gilbertchen/duplicacy/wiki/Snapshot-Format)
+* [Encryption](https://github.com/gilbertchen/duplicacy/wiki/Encryption)

GUIDE.md

@@ -1,515 +1,20 @@
-# Duplicacy User Guide
-
-## Commands
-
-#### Init
-
-```
-SYNOPSIS:
-   duplicacy init - Initialize the storage if necessary and the current directory as the repository
-
-USAGE:
-   duplicacy init [command options] <snapshot id> <storage url>
-
-OPTIONS:
-   -encrypt, -e                    encrypt the storage with a password
-   -chunk-size, -c 4M              the average size of chunks
-   -max-chunk-size, -max 16M       the maximum size of chunks (defaults to chunk-size * 4)
-   -min-chunk-size, -min 1M        the minimum size of chunks (defaults to chunk-size / 4)
-   -pref-dir <preference directory path> 	Specify alternate location for .duplicacy preferences directory
-```
-
-The *init* command first connects to the storage specified by the storage URL.  If the storage has been already been
-initialized before, it will download the storage configuration (stored in the file named *config*) and ignore the options provided in the command line.  Otherwise, it will create the configuration file from the options and upload the file.
-
-The initialized storage will then become the default storage for other commands if the -storage option is not specified
-for those commands.  This default storage actually has a name, *default*.
-
-After that, it will prepare the the current working directory as the repository to be backed up.  Under the hood, it will create a directory
-named *.duplicacy* in the repository and put a file named *preferences* that stores the snapshot id and encryption and storage options.
-
-The snapshot id is an id used to distinguish different repositories connected to the same storage.  Each repository must have a unique snapshot id.  A snapshot id must contain only characters valid in Linux and Windows paths (alphabet, digits, underscore, dash, etc), but cannot include `/`, `\`, or `@`.
-
-The -e option controls whether or not encryption will be enabled for the storage.  If encryption is enabled, you will be prompted to enter a storage password.
-
-The three chunk size parameters are passed to the variable-size chunking algorithm.  Their values are important to the overall performance, especially for cloud storages.  If the chunk size is too small, a lot of overhead will be in sending requests and receiving responses.  If the chunk size is too large, the effect of deduplication will be less obvious as more data will need to be transferred with each chunk.
-
-The -pref-dir controls the location of the preferences directory. If not specified, a directory named .duplicacy is created in the repository. If specified, it must point to a non-existing directory. The directory is created and a .duplicacy file is created in the repository. The .duplicacy file contains the absolute path name to the preferences directory.
-
-Once a storage has been initialized with these parameters, these parameters cannot be modified any more.
-
-#### Backup
-
-```
-SYNOPSIS:
-   duplicacy backup - Save a snapshot of the repository to the storage
-
-USAGE:
-   duplicacy backup [command options]
-
-OPTIONS:
-   -hash                      detect file differences by hash (rather than size and timestamp)
-   -t <tag>                   assign a tag to the backup
-   -stats                     show statistics during and after backup
-   -threads <n>               number of uploading threads
-   -limit-rate <kB/s>         the maximum upload rate (in kilobytes/sec)   
-   -vss                       enable the Volume Shadow Copy service (Windows only)
-   -storage <storage name>    backup to the specified storage instead of the default one
-```
-
-The *backup* command creates a snapshot of the repository and uploads it to the storage.  If -hash is not provided,
-it will upload new or modified files since last backup by comparing file sizes and timestamps.
-Otherwise, every file is scanned to detect changes.
-
-You can assign a tag to the snapshot so that later you can refer to it by tag in other commands.
-
-If the -stats option is specified, statistical information such as transfer speed, the number of chunks will be displayed
-throughout the backup procedure.
-
-The -threads option can be used to specify more than one thread to upload chunks.
-
-The -limit-rate option sets a cape on the maximum upload rate.
-
-The -vss option works on Windows only to turn on the Volume Shadow Copy service such that files opened by other
-processes with exclusive locks can be read as usual.
-
-When the repository can have multiple storages (added by the *add* command), you can select the storage to back up to
-by giving a storage name.
-
-You can specify patterns to include/exclude files by putting them in a file named *.duplicacy/filters*.  Please refer to the [Include/Exclude Patterns](https://github.com/gilbertchen/duplicacy-beta/blob/master/GUIDE.md#includeexclude-patterns) section for how to specify the patterns.
-
-#### Restore
-```
-SYNOPSIS:
-   duplicacy restore - Restore the repository to a previously saved snapshot
-
-USAGE:
-   duplicacy restore [command options] [--] [pattern] ...
-
-OPTIONS:
-   -r <revision>            the revision number of the snapshot (required)
-   -hash                    detect file differences by hash (rather than size and timestamp)
-   -overwrite               overwrite existing files in the repository
-   -delete                  delete files not in the snapshot
-   -stats                   show statistics during and after restore
-   -threads <n>             number of downloading threads
-   -limit-rate <kB/s>	    the maximum download rate (in kilobytes/sec)
-   -storage <storage name>  restore from the specified storage instead of the default one
-```
-
-The *restore* command restores the repository to a previous revision.  By default the restore procedure will treat
-files that have the same sizes and timestamps as those in the snapshot as unchanged files, but with the -hash option, every file will be fully scanned to make sure they are in fact unchanged.
-
-By default the restore procedure will not overwriting existing files, unless the -overwrite option is specified.
-
-The -delete option indicates that files not in the snapshot will be removed.
-
-If the -stats option is specified, statistical information such as transfer speed, number of chunks will be displayed
-throughout the restore procedure.
-
-The -threads option can be used to specify more than one thread to download chunks.
-
-The -limit-rate option sets a cape on the maximum upload rate.
-
-When the repository can have multiple storages (added by the *add* command), you can select the storage to restore from by specifying the storage name.
-
-Unlike the *backup* procedure that reading the include/exclude patterns from a file, the *restore* procedure reads them
-from the command line.  If the patterns can cause confusion to the command line argument parser, -- should be prepended to
-the patterns.  Please refer to the [Include/Exclude Patterns](https://github.com/gilbertchen/duplicacy-beta/blob/master/GUIDE.md#includeexclude-patterns) section for how to specify patterns.
-
-
-#### List
-```
-SYNOPSIS:
-   duplicacy list - List snapshots
-
-USAGE:
-   duplicacy list [command options]  
-
-OPTIONS:
-   -all, -a                    list snapshots with any id
-   -id <snapshot id>           list snapshots with the specified id rather than the default one
-   -r <revision> [+]           the revision number of the snapshot
-   -t <tag>                    list snapshots with the specified tag
-   -files                      print the file list in each snapshot
-   -chunks                     print chunks in each snapshot or all chunks if no snapshot specified
-   -reset-password             take passwords from input rather than keychain/keyring or env
-   -storage <storage name>     retrieve snapshots from the specified storage
-```
-
-The *list* command lists information about specified snapshots.  By default it will list snapshots created from the
-current repository, but you can list all snapshots stored in the storage by specifying the -all option, or list snapshots
-with a different snapshot id using the -id option, and/or snapshots with a particular tag with the -t option.
-
-The revision number is a number assigned to the snapshot when it is being created.  This number will keep increasing
-every time a new snapshot is created from a repository.  You can refer to snapshots by their revision numbers using 
-the -r option, which either takes a single revision number (-r 123) or a range (-r 123-456).
-There can be multiple -r options.
-
-If -files is specified, for each snapshot to be listed, this command will also print information about every file
-contained in the snapshot.
-
-If -chunks is specified, the command will also print out every chunk the snapshot references.
-
-The -reset-password option is used to reset stored passwords and to allow passwords to be entered again.  Please refer to the [Managing Passwords](https://github.com/gilbertchen/duplicacy-beta/blob/master/GUIDE.md#managing-passwords) section for more information.
-
-When the repository can have multiple storages (added by the *add* command), you can specify the storage to list
-by specifying the storage name.
-
-#### Check
-```
-SYNOPSIS:
-   duplicacy check - Check the integrity of snapshots
-
-USAGE:
-   duplicacy check [command options]
-
-OPTIONS:
-   -all, -a                 check snapshots with any id
-   -id <snapshot id>        check snapshots with the specified id rather than the default one
-   -r <revision> [+]        the revision number of the snapshot
-   -t <tag>                 check snapshots with the specified tag
-   -fossils                 search fossils if a chunk can't be found
-   -resurrect               turn referenced fossils back into chunks
-   -files                   verify the integrity of every file
-   -stats                   show deduplication statistics (imply -all and all revisions)
-   -storage <storage name>  retrieve snapshots from the specified storage```
-```
-The *check* command checks, for each specified snapshot, that all referenced chunks exist in the storage.
-
-By default the *check* command will check snapshots created from the
-current repository, but you can check all snapshots stored in the storage at once by specifying the -all option, or
-snapshots from a different repository using the -id option, and/or snapshots with a particular tag with the -t option.
-
-The revision number is a number assigned to the snapshot when it is being created.  This number will keep increasing
-every time a new snapshot is created from a repository.  You can refer to snapshots by their revision numbers using 
-the -r option, which either takes a single revision number (-r 123) or a range (-r 123-456).
-There can be multiple -r options.
-
-By default the *check* command only verifies the existence of chunks.  To verify the full integrity of a snapshot,
-you should specify the -files option, which will download chunks and compute file hashes in memory, to
-make sure that all hashes match.
-
-By default the *check* command does not find fossils. If the -fossils option is specified, it will find
-the fossil if the referenced chunk does not exist.  if the -resurrect option is specified, it will turn the fossil back into a chunk.
-
-When the repository can have multiple storages (added by the *add* command), you can specify the storage to check
-by specifying the storage name.
-
-
-#### Cat
-```
-SYNOPSIS:
-   duplicacy cat - Print to stdout the specified file, or the snapshot content if no file is specified
-
-USAGE:
-   duplicacy cat [command options] [<file>]
-
-OPTIONS:
-   -id <snapshot id>        retrieve from the snapshot with the specified id
-   -r <revision>            the revision number of the snapshot
-   -storage <storage name>  retrieve the file from the specified storage
-```
-
-The *cat* command prints a file or the entire snapshot content if no file is specified.
-
-The file must be specified with a path relative to the repository.
-
-You can specify a different snapshot id rather than the default id.
-
-The -r option is optional.  If not specified, the latest revision will be selected.
-
-You can use the -storage option to select a different storage other than the default one.
-
-#### Diff
-```
-SYNOPSIS:
-   duplicacy diff - Compare two snapshots or two revisions of a file
-
-USAGE:
-   duplicacy diff [command options] [<file>]
-
-OPTIONS:
-   -id <snapshot id>        diff with the snapshot with the specified id
-   -r <revision> [+]        the revision number of the snapshot
-   -hash                    compute the hashes of on-disk files
-   -storage <storage name>  retrieve files from the specified storage
-```
-The *diff* command compares the same file in two different snapshots if a file is given, otherwise compares the
-two snapshots.
-
-The file must be specified with a path relative to the repository.
-
-You can specify a different snapshot id rather than the default snapshot id.
-
-If only one revision is given by -r, the right hand side of the comparison will be the on-disk file.
-The -hash option can then instruct this command to compute the hash of the file. 
-
-You can use the -storage option to select a different storage other than the default one.
-
-#### History
-```
-SYNOPSIS:
-   duplicacy history - Show the history of a file
-
-USAGE:
-   duplicacy history [command options] <file>
-
-OPTIONS:
-   -id <snapshot id>        find the file in the snapshot with the specified id
-   -r <revision> [+]        show history of the specified revisions
-   -hash                    show the hash of the on-disk file
-   -storage <storage name>  retrieve files from the specified storage
-```
-
-The *history* command shows how the hash, size, and timestamp of a file change over the specified set of revisions.
-
-You can specify a different snapshot id rather than the default snapshot id, and multiple -r options to specify the
-set of revisions.
-
-The -hash option is to compute the hash of the on-disk file.  Otherwise, only the size and timestamp of the on-disk
-file will be included.
-
-You can use the -storage option to select a different storage other than the default one.
-
-#### Prune
-```
-SYNOPSIS:
-   duplicacy prune - Prune snapshots by revision, tag, or retention policy
-
-USAGE:
-   duplicacy prune [command options]
-
-OPTIONS:
-   -id <snapshot id>        delete snapshots with the specified id instead of the default one
-   -all, -a                 match against all snapshot IDs
-   -r <revision> [+]        delete snapshots with the specified revisions
-   -t <tag> [+]             delete snapshots with the specified tags
-   -keep <n:m> [+]          keep 1 snapshot every n days for snapshots older than m days
-   -exhaustive              find all unreferenced chunks by scanning the storage
-   -exclusive               assume exclusive access to the storage (disable two-step fossil collection)
-   -dry-run, -d             show what would have been deleted
-   -delete-only             delete fossils previously collected (if deletable) and don't collect fossils
-   -collect-only            identify and collect fossils, but don't delete fossils previously collected
-   -ignore <id> [+]         ignore the specified snapshot id when deciding if fossils can be deleted
-   -storage <storage name>  prune snapshots from the specified storage
-```
-
-The *prune* command implements the two-step fossil collection algorithm.  It will first find fossil collection files
-from previous runs and check if contained fossils are eligible for permanent deletion (the fossil deletion step).  Then it
-will search for snapshots to be deleted, mark unreferenced chunks as fossils (by renaming) and save them in a new fossil
-collection file stored locally (the fossil collection step).
-
-If a snapshot id is specified, that snapshot id will be used instead of the default one.  The -a option will find
-snapshots with any id.  Snapshots to be deleted can be specified by revision numbers, by a tag, by retention policies,
-or by any combination of them.
-
-The retention policies are specified by the -keep option, which accepts an argument in the form of two numbers *n:m*, where *n* indicates the number of days between two consecutive snapshots to keep, and *m* means that the policy only applies to snapshots at least *m* day old.  If *n* is zero, any snapshots older than *m* days will be removed.
-
-Here are a few sample retention policies:
-
-```sh
-$ duplicacy prune -keep 1:7       # Keep 1 snapshot per day for snapshots older than 7 days
-$ duplicacy prune -keep 7:30      # Keep 1 snapshot every 7 days for snapshots older than 30 days
-$ duplicacy prune -keep 30:180    # Keep 1 snapshot every 30 days for snapshots older than 180 days
-$ duplicacy prune -keep 0:360     # Keep no snapshots older than 360 days
-```
-
-Multiple -keep options must be sorted by their *m* values in decreasing order.  For instance, to combine the above policies into one line, it would become:
-
-```sh
-$ duplicacy prune -keep 0:360 -keep 30:180 -keep 7:30 -keep 1:7
-```
-
-The -exhaustive option will scan the list of all chunks in the storage, therefore it will find not only 
-unreferenced chunks from deleted snapshots, but also chunks that become unreferenced for other reasons, such as
-those from an incomplete backup.  It will also find any file that does not look like a chunk file.
-In contrast, a default *prune* command will only identify 
-chunks referenced by deleted snapshots but not any other snapshots.
-
-The -exclusive option will assume that no other clients are accessing the storage, effectively disabling the 
-*two-step fossil collection* algorithm.  With this option, the *prune* command will immediately remove unreferenced chunks.
-
-The -dryrun option is used to test what changes the *prune* command would have done.  It is guaranteed not to make
-any changes on the storage, not even creating the local fossil collection file.  The following command checks if the
-chunk directory is clean (i.e., if there are any unreferenced chunks, temporary files, or anything else):
-
-```
-$ duplicacy prune -d -exclusive -exhaustive    #  Prints out nothing if the chunk directory is clean
-```
-
-The -delete-only option will skip the fossil collection step, while the -collect-only option will skip the fossil deletion step.
-
-For fossils collected in the fossil collection step to be eligible for safe deletion in the fossil deletion step, at least
-one new snapshot from *each* snapshot id must be created between two runs of the *prune* command.  However, some repository
-may not be set up to back up with a regular schedule, and thus literally blocking other repositories from deleting any fossils.  Duplicacy by default will ignore repositories that have no new backup in the past 7 days.  It also provide an
--ignore option that can be used to skip certain repositories when deciding the deletion criteria.
-
-You can use the -storage option to select a different storage other than the default one.
-
-
-#### Password
-```
-SYNOPSIS:
-   duplicacy password - Change the storage password
-
-USAGE:
-   duplicacy password [command options]
-
-OPTIONS:
-   -storage <storage name>  change the password used to access the specified storage
-```
-
-The *password* command decrypts the storage configuration file *config* using the old password, and re-encrypts the file
-using a new password.  It does not change all the encryption keys used to encrypt and decrypt chunk files,
-snapshot files, etc.
-
-You can specify the storage to change the password for when working with multiple storages.
-
-
-#### Add
-```
-SYNOPSIS:
-   duplicacy add - Add an additional storage to be used for the existing repository
-
-USAGE:
-   duplicacy add [command options] <storage name> <snapshot id> <storage url>
-
-OPTIONS:
-   -encrypt, -e                    Encrypt the storage with a password
-   -chunk-size, -c 4M              the average size of chunks
-   -max-chunk-size, -max 16M       the maximum size of chunks (defaults to chunk-size * 4)
-   -min-chunk-size, -min 1M        the minimum size of chunks (defaults to chunk-size / 4)
-   -compression-level, -l <level>  compression level (defaults to -1)
-   -copy <storage name>            make the new storage copy-compatible with an existing one
-```
-
-The *add* command connects another storage to the current repository.  Like the *init* command, if the storage has not
-been initialized before, a storage configuration file derived from the command line options will be uploaded, but those
-options will be ignored if the configuration file already exists in the storage.
-
-A unique storage name must be given in order to distinguish it from other storages.
-
-The -copy option is required if later you want to copy snapshots between this storage and another storage.
-Two storages are copy-compatible if they have the same average chunk size, the same maximum chunk size,
-the same minimum chunk size, the same chunk seed (used in calculating the rolling hash in the variable-size chunks
-algorithm), and the same hash key.  If the -copy option is specified, these parameters will be copied from
-the existing storage rather than from the command line.
-
-#### Set
-```
-SYNOPSIS:
-   duplicacy set - Change the options for the default or specified storage
-
-USAGE:
-   duplicacy set [command options]
-
-OPTIONS:
-   -encrypt, e[=true]       encrypt the storage with a password
-   -no-backup[=true]        backup to this storage is prohibited
-   -no-restore[=true]       restore from this storage is prohibited
-   -no-save-password[=true] don't save password or access keys to keychain/keyring
-   -key                     add a key/password whose value is supplied by the -value option
-   -value                   the value of the key/password
-   -storage <storage name>  use the specified storage instead of the default one
-```
-
-The *set* command changes the options for the specified storage.
-
-The -e option turns on the storage encryption.  If specified as -e=false, it turns off the storage encryption.
-
-The -no-backup option will not allow backups from this repository to be created.
-
-The -no-restore option will not allow restoring this repository to a different revision.
-
-The -no-save-password option will require every password or token to be entered every time and not saved anywhere.
-
-The -key and -value options are used to store (in plain text) access keys or tokens need by various storages.  Please
-refer to the [Managing Passwords](https://github.com/gilbertchen/duplicacy-beta/blob/master/GUIDE.md#managing-passwords) section for more details.
-
-You can select a storage to change options for by specifying a storage name.
-
-
-#### Copy
-```
-SYNOPSIS:
-   duplicacy copy - Copy snapshots between compatible storages
-
-USAGE:
-   duplicacy copy [command options]
-
-OPTIONS:
-   -id <snapshot id>     copy snapshots with the specified id instead of all snapshot ids
-   -r <revision> [+]     copy snapshots with the specified revisions
-   -from <storage name>  copy snapshots from the specified storage
-   -to <storage name>    copy snapshots to the specified storage
-```
-
-The *copy* command copies snapshots from one storage to another storage.  They must be copy-compatible, i.e., some
-configuration parameters must be the same.  One storage must be initialized with the -copy option provided by the *add* command.
-
-Instead of copying all snapshots, you can specify a set of snapshots to copy by giving the -r options.  The *copy* command
-preserves the revision numbers, so if a revision number already exists on the destination storage the command will fail.
-
-If no -from option is given, the snapshots from the default storage will be copied.  The -to option specified the
-destination storage and is required.
-
-## Include/Exclude Patterns
-
-An include pattern starts with +, and an exclude pattern starts with -.  Patterns may contain wildcard characters * which matches a path string of any length, and ? matches a single character.  Note that both * and ? will match any character including the path separator /.
-
-When matching a path against a list of patterns, the path is compared with the part after + or -, one pattern at a time.  Therefore, the order of the patterns is significant.  If a match with an include pattern is found, the path is said to be included without further comparisons.  If a match with an exclude pattern is found, the path is said to be excluded without further comparison.  If a match is not found, the path will be excluded if all patterns are include patterns, but included otherwise.
-
-Patterns ending with a / apply to directories only, and patterns not ending with a / apply to files only.  When a directory is excluded, all files and subdirectires under it will also be excluded.  Note that the path separator is always /, even on Windows.
-
-The following pattern list includes only files under the directory foo/ but not files under the subdirectory foo/bar:
-
-```
--foo/bar/
-+foo/*
--*
-```
-
-For the *backup* command, the include/exclude patterns are read from a file named *filters* under the *.duplicacy* directory.
-
-For the *restore* command, the include/exclude patterns are specified as the command line arguments.
-
-
-## Managing Passwords
-
-Duplicacy will attempt to retrieve in three ways the storage password and the storage-specific access tokens/keys.
-
-* If a secret vault service is available, Duplicacy will store passwords/keys entered by the user in such a secret vault and later retrieve them when needed.  On Mac OS X it is Keychain, and on Linux it is gnome-keyring.  On Windows the passwords/keys are encrypted and decrypted by the Data Protection API, and encrypted passwords/keys are stored in the file *.duplicacy/keyring*.  However, if the -no-save-password option is specified for the storage, then Duplicacy will not save passwords this way.
-* If an environment variable for a password is provided, Duplicacy will always take it.  The table below shows the name of the environment variable for each kind of password.  Note that if the storage is not the default one, the storage name will be included in the name of the environment variable.
-* If a matching key and its value are saved to the preference file (.duplicacy/preferences) by the *set* command, the value will be used as the password.  The last column in the table below lists the name of the preference key for each type of password.
-
-| password type | environment variable (default storage) | environment variable (non-default storage) | key in preferences  |
-|:----------------:|:----------------:|:----------------:|:----------------:|
-| storage password | DUPLICACY_PASSWORD | DUPLICACY_&lt;STORAGENAME&gt;_PASSWORD | password |
-| sftp password | DUPLICACY_SSH_PASSWORD | DUPLICACY_&lt;STORAGENAME&gt;_SSH_PASSWORD | ssh_password |
-| sftp key file | DUPLICACY_SSH_KEY_FILE | DUPLICACY_&lt;STORAGENAME&gt;_SSH_KEY_FILE | ssh_key_file |
-| Dropbox Token | DUPLICACY_DROPBOX_TOKEN | DUPLICACY_&lt;STORAGENAME>&gt;_DROPBOX_TOKEN | dropbox_token |
-| S3 Access ID | DUPLICACY_S3_ID | DUPLICACY_&lt;STORAGENAME&gt;_S3_ID | s3_id |
-| S3 Secret Key | DUPLICACY_S3_SECRET | DUPLICACY_&lt;STORAGENAME&gt;_S3_SECRET | s3_secret |
-| BackBlaze Account ID | DUPLICACY_B2_ID | DUPLICACY_&lt;STORAGENAME&gt;_B2_ID | b2_id |
-| Backblaze Application Key | DUPLICACY_B2_KEY | DUPLICACY_&lt;STORAGENAME&gt;_B2_KEY | b2_key |
-| Azure Access Key | DUPLICACY_AZURE_KEY | DUPLICACY_&lt;STORAGENAME&gt;_AZURE_KEY | azure_key |
-| Google Drive Token File | DUPLICACY_GCD_TOKEN | DUPLICACY_&lt;STORAGENAME&gt;_GCD_TOKEN | gcd_token |
-| Microsoft OneDrive Token File | DUPLICACY_ONE_TOKEN | DUPLICACY_&lt;STORAGENAME&gt;_ONE_TOKEN | one_token |
-| Hubic Token File | DUPLICACY_HUBIC_TOKEN | DUPLICACY_&lt;STORAGENAME&gt;_HUBIC_TOKEN | hubic_token |
-
-Note that the passwords stored in the environment variable and the preference need to be in plaintext and thus are insecure and should be avoided whenever possible.
-
-## Cache
-
-Duplicacy maintains a local cache under the `.duplicacy/cache` folder in the repository.  Only snapshot chunks may be stored in this local cache, and file chunks are never cached.
-
-At the end of a backup operation, Duplicacy will clean up the local cache in such a way that only chunks composing the snapshot file from the last backup will stay in the cache.  All other chunks will be removed from the cache.  However, if the *prune* command has been run before (which will leave a the `.duplicacy/collection` folder in the repository, then the *backup* command won't perform any cache cleanup and instead defer that to the *prune* command.
-
-At the end of a prune operation, Duplicacy will remove all chunks from the local cache except those composing the snapshot file from the last backup (those that would be kept by the *backup* command), as well as chunks that contain information about chunks referenced by *all* backups from *all* repositories connected to the same storage url.  
-
-Other commands, such as *list*, *check*, does not clean up the local cache at all, so the local cache may keep growing if many of these commands run consecutively.  However, once a *backup* or a *prune* command is invoked, the local cache should shrink to its normal size.
-
-## Scripts
-
-You can instruct Duplicacy to run a script before or after executing a command.  For example, if you create a bash script with the name *pre-prune* under the *.duplicacy/scripts* directory, this bash script will be run before the *prune* command starts.  A script named *post-prune* will be run after the *prune* command finishes.  This rule applies to all commands except *init*.
+All documentation has been moved to our wiki page:
+
+* Commands
+    * [init](https://github.com/gilbertchen/duplicacy/wiki/init)
+    * [backup](https://github.com/gilbertchen/duplicacy/wiki/backup)
+    * [restore](https://github.com/gilbertchen/duplicacy/wiki/restore)
+    * [list](https://github.com/gilbertchen/duplicacy/wiki/list)
+    * [check](https://github.com/gilbertchen/duplicacy/wiki/check)
+    * [prune](https://github.com/gilbertchen/duplicacy/wiki/prune)
+    * [cat](https://github.com/gilbertchen/duplicacy/wiki/cat)
+    * [history](https://github.com/gilbertchen/duplicacy/wiki/history)
+    * [diff](https://github.com/gilbertchen/duplicacy/wiki/diff)
+    * [password](https://github.com/gilbertchen/duplicacy/wiki/password)
+    * [add](https://github.com/gilbertchen/duplicacy/wiki/add)
+    * [set](https://github.com/gilbertchen/duplicacy/wiki/set)
+    * [copy](https://github.com/gilbertchen/duplicacy/wiki/copy)
+* [Include/Exclude Patterns](https://github.com/gilbertchen/duplicacy/wiki/Include-Exclude-Patterns)
+* [Managing Passwords](https://github.com/gilbertchen/duplicacy/wiki/Managing-Passwords)
+* [Cache](https://github.com/gilbertchen/duplicacy/wiki/Cache)
+* [Pre-Command and Post-Command Scripts](https://github.com/gilbertchen/duplicacy/wiki/Pre-Command-and-Post-Command-Scripts)

LICENSE.md

@@ -1,5 +1,7 @@
 Copyright © 2017 Acrosync LLC
 
 * Free for personal use or commercial trial
-* Non-trial commercial use requires per-user licenses available from [duplicacy.com](https://duplicacy.com/customer) at a cost of $20 per year
+* Non-trial commercial use requires per-computer CLI licenses available from [duplicacy.com](https://duplicacy.com/buy.html) at a cost of $50 per year
+* The computer with a valid commercial license for the GUI version may run the CLI version without a CLI license
+* CLI licenses are not required to restore or manage backups; only the backup command requires valid CLI licenses
 * Modification and redistribution are permitted, but commercial use of derivative works is subject to the same requirements of this license

README.md

@@ -1,306 +1,100 @@
 # Duplicacy: A lock-free deduplication cloud backup tool
 
-Duplicacy is a new generation cross-platform cloud backup tool based on the idea of [Lock-Free Deduplication](https://github.com/gilbertchen/duplicacy-cli/blob/master/DESIGN.md).  It is the only cloud backup tool that allows multiple computers to back up to the same storage simultaneously without using any locks (thus readily amenable to various cloud storage services).
+Duplicacy is a new generation cross-platform cloud backup tool based on the idea of [Lock-Free Deduplication](https://github.com/gilbertchen/duplicacy/wiki/Lock-Free-Deduplication).
 
-The repository hosts source code, design documents, and binary releases of the command line version.  There is also a Duplicacy GUI frontend built for Windows and Mac OS X available from https://duplicacy.com.
+Our paper explaining the inner workings of Duplicacy has been accepted by [IEEE Transactions on Cloud Computing](https://ieeexplore.ieee.org/document/9310668) and will appear in a future issue this year.  The final draft version is available [here](https://github.com/gilbertchen/duplicacy/blob/master/duplicacy_paper.pdf) for those who don't have IEEE subscriptions. 
+
+This repository hosts source code, design documents, and binary releases of the command line version of Duplicacy.  There is also a Web GUI frontend built for Windows, macOS, and Linux, available from https://duplicacy.com.
 
 There is a special edition of Duplicacy developed for VMware vSphere (ESXi) named [Vertical Backup](https://www.verticalbackup.com) that can back up virtual machine files on ESXi to local drives, network or cloud storages.
 
 ## Features
 
-Duplicacy currently supports major cloud storage providers (Amazon S3, Google Cloud Storage, Microsoft Azure, Dropbox, Backblaze, Google Drive, Microsoft OneDrive, and Hubic) and offers all essential features of a modern backup tool:
+There are 3 core advantages of Duplicacy over any other open-source or commercial backup tools:
 
-* Incremental backup: only back up what has been changed
-* Full snapshot : although each backup is incremental, it must behave like a full snapshot for easy restore and deletion
-* Deduplication: identical files must be stored as one copy (file-level deduplication), and identical parts from different files must be stored as one copy (block-level deduplication)
-* Encryption: encrypt not only file contents but also file paths, sizes, times, etc.
-* Deletion: every backup can be deleted independently without affecting others
-* Concurrent access: multiple clients can back up to the same storage at the same time
-* Snapshot migration: all or selected snapshots can be migrated from one storage to another
+* Duplicacy is the *only* cloud backup tool that allows multiple computers to back up to the same cloud storage, taking advantage of cross-computer deduplication whenever possible, without direct communication among them.  This feature turns any cloud storage server supporting only a basic set of file operations into a sophisticated deduplication-aware server.  
 
-The key idea of **Lock-Free Deduplication** can be summarized as follows:
+* Unlike other chunk-based backup tools where chunks are grouped into pack files and a chunk database is used to track which chunks are stored inside each pack file, Duplicacy takes a database-less approach where every chunk is saved independently using its hash as the file name to facilitate quick lookups.  The avoidance of a centralized chunk database not only produces a simpler and less error-prone implementation, but also makes it easier to develop advanced features, such as [Asymmetric Encryption](https://github.com/gilbertchen/duplicacy/wiki/RSA-encryption) for stronger encryption and [Erasure Coding](https://github.com/gilbertchen/duplicacy/wiki/Erasure-coding) for resilient data protection.
 
-* Use variable-size chunking algorithm to split files into chunks
-* Store each chunk in the storage using a file name derived from its hash, and rely on the file system API to manage chunks without using a centralized indexing database
-* Apply a *two-step fossil collection* algorithm to remove chunks that become unreferenced after a backup is deleted
+* Duplicacy is fast.  While the performance wasn't the top-priority design goal, Duplicacy has been shown to outperform other backup tools by a considerable margin, as indicated by the following results obtained from a [benchmarking experiment](https://github.com/gilbertchen/benchmarking) backing up the [Linux code base](https://github.com/torvalds/linux) using Duplicacy and 3 other open-source backup tools.
+
+[![Comparison of Duplicacy, restic, Attic, duplicity](https://github.com/gilbertchen/duplicacy/blob/master/images/duplicacy_benchmark_speed.png "Comparison of Duplicacy, restic, Attic, duplicity")](https://github.com/gilbertchen/benchmarking)
 
-The [design document](https://github.com/gilbertchen/duplicacy-cli/blob/master/DESIGN.md) explains lock-free deduplication in detail.
 
 ## Getting Started
 
-<details>
-<summary>Installation</summary>
-
-Duplicacy is written in Go.  You can run the following command to build the executable (which will be created under `$GOPATH/bin`):
-
-```
-go get -u github.com/gilbertchen/duplicacy/...
-```
-
-You can also visit the [releases page](https://github.com/gilbertchen/duplicacy-cli/releases/latest) to download the pre-built binary suitable for your platform..
-
-</details>
-
-<details>
-<summary>Commands</summary>
-
-Once you have the Duplicacy executable on your path, you can change to the directory that you want to back up (called *repository*) and run the *init* command:
-
-```
-$ cd path/to/your/repository
-$ duplicacy init mywork sftp://user@192.168.1.100/path/to/storage
-```
-
-This *init* command connects the repository with the remote storage at 192.168.1.00 via SFTP.  It will initialize the remote storage if this has not been done before.  It also assigns the snapshot id *mywork* to the repository.  This snapshot id is used to uniquely identify this repository if there are other repositories that also back up to the same storage.
-
-You can now create snapshots of the repository by invoking the *backup* command.  The first snapshot may take a while depending on the size of the repository and the upload bandwidth.  Subsequent snapshots will be much faster, as only new or modified files will be uploaded.  Each snapshot is identified by the snapshot id and an increasing revision number starting from 1.
-
-```sh
-$ duplicacy backup -stats
-```
-
-The *restore* command rolls back the repository to a previous revision:
-```sh
-$ duplicacy restore -r 1
-```
-
-
-
-Duplicacy provides a set of commands, such as list, check, diff, cat history, to manage snapshots:
-
-
-```makefile
-$ duplicacy list            # List all snapshots
-$ duplicacy check           # Check integrity of snapshots
-$ duplicacy diff            # Compare two snapshots, or the same file in two snapshots
-$ duplicacy cat             # Print a file in a snapshot
-$ duplicacy history         # Show how a file changes over time
-```
-
-
-The *prune* command removes snapshots by revisions, or tags, or retention policies:
-
-```sh
-$ duplicacy prune -r 1            # Remove the snapshot with revision number 1
-$ duplicacy prune -t quick        # Remove all snapshots with the tag 'quick'
-$ duplicacy prune -keep 1:7       # Keep 1 snapshot per day for snapshots older than 7 days
-$ duplicacy prune -keep 7:30      # Keep 1 snapshot every 7 days for snapshots older than 30 days
-$ duplicacy prune -keep 0:180     # Remove all snapshots older than 180 days
-```
-
-The first time the *prune* command is called, it removes the specified snapshots but keeps all unreferenced chunks as fossils.
-Since it uses the two-step fossil collection algorithm to clean chunks, you will need to run it again to remove those fossils from the storage:
-
-```sh
-$ duplicacy prune           # Chunks from deleted snapshots will be removed if deletion criteria are met
-```
-
-To back up to multiple storages, use the *add* command to add a new storage.  The *add* command is similar to the *init* command, except that the first argument is a storage name used to distinguish different storages:
-
-```sh
-$ duplicacy add s3 mywork s3://amazon.com/mybucket/path/to/storage
-```
-
-You can back up to any storage by specifying the storage name:
-
-```sh
-$ duplicacy backup -storage s3
-```
-
-However, snapshots created this way will be different on different storages, if the repository has been changed during two backup operations.  A better approach, is to use the *copy* command to copy specified snapshots from one storage to another:
-
-```sh
-$ duplicacy copy -r 1 -to s3   # Copy snapshot at revision 1 to the s3 storage
-$ duplicacy copy -to s3        # Copy every snapshot to the s3 storage
-```
-
-</details>
-
-
-The [User Guide](https://github.com/gilbertchen/duplicacy-cli/blob/master/GUIDE.md) contains a complete reference to
-all commands and other features of Duplicacy.
-
+* [A brief introduction](https://github.com/gilbertchen/duplicacy/wiki/Quick-Start)
+* [Command references](https://github.com/gilbertchen/duplicacy/wiki)
+* [Building from source](https://github.com/gilbertchen/duplicacy/wiki/Installation)
 
 ## Storages
 
-Duplicacy currently supports local file storage, SFTP, and many cloud storage providers.
+Duplicacy currently provides the following storage backends:
 
-<details> <summary>Local disk</summary>
+* Local disk
+* SFTP
+* Dropbox
+* Amazon S3
+* Wasabi
+* DigitalOcean Spaces
+* Google Cloud Storage
+* Microsoft Azure
+* Backblaze B2
+* Google Drive
+* Microsoft OneDrive
+* Hubic
+* OpenStack Swift
+* WebDAV (under beta testing)
+* pcloud (via WebDAV)
+* Box.com (via WebDAV)
+* File Fabric by [Storage Made Easy](https://storagemadeeasy.com/)
 
-```
-Storage URL:  /path/to/storage (on Linux or Mac OS X)
-              C:\path\to\storage (on Windows)
-```
-</details>
+Please consult the [wiki page](https://github.com/gilbertchen/duplicacy/wiki/Storage-Backends) on how to set up Duplicacy to work with each cloud storage.
 
-<details> <summary>SFTP</summary> 
-
-```
-Storage URL:  sftp://username@server/path/to/storage
-```
-
-Login methods include password authentication and public key authentication.  Due to a limitation of the underlying Go SSH library, the key pair for public key authentication must be generated without a passphrase.  To work with a key that has a passphrase, you can set up SSH agent forwarding which is also supported by Duplicacy.
-
-</details>
-
-<details> <summary>Dropbox</summary>
-
-```
-Storage URL:  dropbox://path/to/storage
-```
-
-For Duplicacy to access your Dropbox storage, you must provide an access token that can be obtained in one of two ways:
-
-* Create your own app on the [Dropbox Developer](https://www.dropbox.com/developers) page, and then generate the [access token](https://blogs.dropbox.com/developers/2014/05/generate-an-access-token-for-your-own-account/)
-
-* Or authorize Duplicacy to access its app folder inside your Dropbox (following [this link](https://dl.dropboxusercontent.com/u/95866350/start_dropbox_token.html)), and Dropbox will generate the access token (which is not visible to us, as the redirect page showing the token is merely a static html hosted by Dropbox)
-
-Dropbox has two advantages over other cloud providers.  First, if you are already a paid user then to use the unused space as the backup storage is basically free.  Second, unlike other providers Dropbox does not charge bandwidth or API usage fees.
-
-</details>
-
-<details> <summary>Amazon S3</summary>
-
-```
-Storage URL:  s3://amazon.com/bucket/path/to/storage (default region is us-east-1)
-              s3://region@amazon.com/bucket/path/to/storage (other regions must be specified)
-```
-
-You'll need to input an access key and a secret key to access your Amazon S3 storage.
+For reference, the following chart shows the running times (in seconds) of backing up the [Linux code base](https://github.com/torvalds/linux) to each of those supported storages:
 
 
-</details>
+[![Comparison of Cloud Storages](https://github.com/gilbertchen/duplicacy/blob/master/images/duplicacy_benchmark_cloud.png "Comparison of Cloud Storages")](https://github.com/gilbertchen/cloud-storage-comparison)
 
-<details>  <summary>Google Cloud Storage</summary>
 
-```
-Storage URL:  gcs://bucket/path/to/storage
-```
+For complete benchmark results please visit https://github.com/gilbertchen/cloud-storage-comparison.
 
-Starting from version 2.0.0, a new Google Cloud Storage backend is added which is implemented using the [official Google client library](https://godoc.org/cloud.google.com/go/storage).  You must first obtain a credential file by [authorizing](https://duplicacy.com/gcp_start) Duplicacy to access your Google Cloud Storage account or by [downloading](https://console.cloud.google.com/projectselector/iam-admin/serviceaccounts) a service account credential file.
- 
-You can also use the s3 protocol to access Google Cloud Storage.  To do this, you must enable the [s3 interoperability](https://cloud.google.com/storage/docs/migrating#migration-simple) in your Google Cloud Storage settings and set the storage url as `s3://storage.googleapis.com/bucket/path/to/storage`.
-
-</details>
-
-<details> <summary>Microsoft Azure</summary>
-
-```
-Storage URL:  azure://account/container
-```
-
-You'll need to input the access key once prompted.
-
-</details>
-
-<details> <summary>Backblaze B2</summary>
-
-```
-Storage URL: b2://bucket
-```
-
-You'll need to input the account id and application key.
-
-Backblaze's B2 storage is not only the least expensive (at 0.5 cent per GB per month), but also the fastest.  We have been working closely with their developers to leverage the full potentials provided by the B2 API in order to maximize the transfer speed.
-
-</details>
-
-<details> <summary>Google Drive</summary>
-
-```
-Storage URL: gcd://path/to/storage
-```
-
-To use Google Drive as the storage,  you first need to download a token file from https://duplicacy.com/gcd_start by
-authorizing Duplicacy to access your Google Drive, and then enter the path to this token file to Duplicacy when prompted.
-
-</details>
-
-<details> <summary>Microsoft OneDrive</summary>
-
-```
-Storage URL: one://path/to/storage
-```
-
-To use Microsoft OneDrive as the storage,  you first need to download a token file from https://duplicacy.com/one_start by
-authorizing Duplicacy to access your OneDrive, and then enter the path to this token file to Duplicacy when prompted.
-
-</details>
-
-<details> <summary>Hubic</summary>
-
-```
-Storage URL: hubic://path/to/storage
-```
-
-To use Hubic as the storage,  you first need to download a token file from https://duplicacy.com/hubic_start by
-authorizing Duplicacy to access your Hubic drive, and then enter the path to this token file to Duplicacy when prompted.
-
-Hubic offers the most free space (25GB) of all major cloud providers and there is no bandwidth charge (same as Google Drive and OneDrive), so it may be worth a try.
-
-</details>
-
-## Feature Comparison with Other Backup Tools
+## Comparison with Other Backup Tools
 
 [duplicity](http://duplicity.nongnu.org) works by applying the rsync algorithm (or more specific, the [librsync](https://github.com/librsync/librsync) library)
 to find the differences from previous backups and only then uploading the differences.  It is the only existing backup tool with extensive cloud support -- the [long list](http://duplicity.nongnu.org/duplicity.1.html#sect7) of storage backends covers almost every cloud provider one can think of.  However, duplicity's biggest flaw lies in its incremental model -- a chain of dependent backups starts with a full backup followed by a number of incremental ones, and ends when another full backup is uploaded.  Deleting one backup will render useless all the subsequent backups on the same chain.  Periodic full backups are required, in order to make previous backups disposable.
 
 [bup](https://github.com/bup/bup) also uses librsync to split files into chunks but save chunks in the git packfile format.  It doesn't support any cloud storage, or deletion of old backups.
 
-[Obnam](http://obnam.org) got the incremental backup model right in the sense that every incremental backup is actually a full snapshot.  Although Obnam also splits files into chunks, it does not adopt either the rsync algorithm or the variable-size chunking algorithm.  As a result, deletions or insertions of a few bytes will foil the
-[deduplication](http://obnam.org/faq/dedup).
-Deletion of old backups is possible, but no cloud storages are supported.
-Multiple clients can back up to the same storage, but only sequential access is granted by the [locking on-disk data structures](http://obnam.org/locking/).
-It is unclear if the lack of cloud backends is due to difficulties in porting the locking data structures to cloud storage APIs.
+[Duplicati](https://duplicati.com) is one of the first backup tools that adopt the chunk-based approach to split files into chunks which are then uploaded to the storage.  The chunk-based approach got the incremental backup model right in the sense that every incremental backup is actually a full snapshot.  As Duplicati splits files into fixed-size chunks,  deletions or insertions of a few bytes will foil the deduplication.  Cloud support is extensive, but multiple clients can't back up to the same storage location.
 
-[Attic](https://attic-backup.org) has been acclaimed by some as the [Holy Grail of backups](https://www.stavros.io/posts/holy-grail-backups).  It follows the same incremental backup model as Obnam, but embraces the variable-size chunk algorithm for better performance and better deduplication.  Deletions of old backup is also supported.  However, no cloud backends are implemented, as in Obnam.  Although concurrent backups from multiple clients to the same storage is in theory possible by the use of locking, it is 
+[Attic](https://attic-backup.org) has been acclaimed by some as the [Holy Grail of backups](https://www.stavros.io/posts/holy-grail-backups).  It follows the same incremental backup model like Duplicati but embraces the variable-size chunk algorithm for better performance and higher deduplication efficiency (not susceptible to byte insertion and deletion any more).  Deletions of old backup are also supported.  However, no cloud backends are implemented.  Although concurrent backups from multiple clients to the same storage is in theory possible by the use of locking, it is
 [not recommended](http://librelist.com/browser//attic/2014/11/11/backing-up-multiple-servers-into-a-single-repository/#e96345aa5a3469a87786675d65da492b) by the developer due to chunk indices being kept in a local cache.
-Concurrent access is not only a convenience; it is a necessity for better deduplication.  For instance, if multiple machines with the same OS installed can back up their entire drives to the same storage, only one copy of the system files needs to be stored, greatly reducing the storage space regardless of the number of machines.  Attic still adopts the traditional approach of using a centralized indexing database to manage chunks, and relies heavily on caching to improve performance.  The presence of exclusive locking makes it hard to be adapted for cloud storage APIs and reduces the level of deduplication.
+Concurrent access is not only a convenience; it is a necessity for better deduplication.  For instance, if multiple machines with the same OS installed can back up their entire drives to the same storage, only one copy of the system files needs to be stored, greatly reducing the storage space regardless of the number of machines.  Attic still adopts the traditional approach of using a centralized indexing database to manage chunks and relies heavily on caching to improve performance.  The presence of exclusive locking makes it hard to be extended to cloud storages.
 
-[restic](https://restic.github.io) is a more recent addition.  It is worth mentioning here because, like Duplicacy, it is written in Go.  It uses a format similar to the git packfile format.  Multiple clients backing up to the same storage are still guarded by 
-[locks](https://github.com/restic/restic/blob/master/doc/Design.md#locks).  A prune operation will therefore completely block all other clients connected to the storage from doing their regular backups.  Moreover, since most cloud storage services do not provide a locking service, the best effort is to use some basic file operations to simulate a lock, but distributed locking is known to be a hard problem and it is unclear how reliable restic's lock implementation is.  A faulty implementation may cause a prune operation to accidentally delete data still in use, resulting in unrecoverable data loss.  This is the exact problem that we avoided by taking the lock-free approach.
+[restic](https://restic.github.io) is a more recent addition. It uses a format similar to the git packfile format.  Multiple clients backing up to the same storage are still guarded by
+[locks](https://github.com/restic/restic/blob/master/doc/Design.md#locks), and because a chunk database is used, deduplication isn't real-time (different clients sharing the same files will upload different copies of the same chunks).  A prune operation will completely block all other clients connected to the storage from doing their regular backups.  Moreover, since most cloud storage services do not provide a locking service, the best effort is to use some basic file operations to simulate a lock, but distributed locking is known to be a hard problem and it is unclear how reliable restic's lock implementation is.  A faulty implementation may cause a prune operation to accidentally delete data still in use, resulting in unrecoverable data loss.  This is the exact problem that we avoided by taking the lock-free approach.
 
 
 The following table compares the feature lists of all these backup tools:
 
 
-| Feature/Tool       | duplicity | bup | Obnam             | Attic           | restic            | **Duplicacy** | 
+| Feature/Tool       | duplicity | bup | Duplicati         | Attic           | restic            | **Duplicacy** |
 |:------------------:|:---------:|:---:|:-----------------:|:---------------:|:-----------------:|:-------------:|
 | Incremental Backup | Yes       | Yes | Yes               | Yes             | Yes               | **Yes**       |
 | Full Snapshot      | No        | Yes | Yes               | Yes             | Yes               | **Yes**       |
+| Compression        | Yes       | Yes | Yes               | Yes             | No                | **Yes**       |
 | Deduplication      | Weak      | Yes | Weak              | Yes             | Yes               | **Yes**       |
 | Encryption         | Yes       | Yes | Yes               | Yes             | Yes               | **Yes**       |
 | Deletion           | No        | No  | Yes               | Yes             | No                | **Yes**       |
-| Concurrent Access  | No        | No  | Exclusive locking | Not recommended | Exclusive locking | **Lock-free** |
-| Cloud Support      | Extensive | No  | No                | No              | S3, B2, OpenStack | **S3, GCS, Azure, Dropbox, Backblaze B2, Google Drive, OneDrive, and Hubic**|
+| Concurrent Access  | No        | No  | No                | Not recommended | Exclusive locking | **Lock-free** |
+| Cloud Support      | Extensive | No  | Extensive         | No              | Limited           | **Extensive** |
 | Snapshot Migration | No        | No  | No                | No              | No                | **Yes**       |
 
-
-## Performance Comparison with Other Backup Tools
-
-Duplicacy is not only more feature-rich but also faster than other backup tools.  The following table lists the running times in seconds of backing up the [Linux code base](https://github.com/torvalds/linux) using Duplicacy and 3 other tools.  Clearly Duplicacy is the fastest by a significant margin.
-
-
-|                    |   Duplicacy  |   restic   |   Attic    |  duplicity  | 
-|:------------------:|:----------------:|:----------:|:----------:|:-----------:|
-| Initial backup | 13.7 | 20.7 | 26.9 | 44.2 | 
-| 2nd backup | 4.8  |  8.0 | 15.4 | 19.5 | 
-| 3rd backup | 6.9  | 11.9 | 19.6 | 29.8 | 
-| 4th backup | 3.3  | 7.0  | 13.7 | 18.6 | 
-| 5th backup | 9.9  | 11.4 | 19.9 | 28.0 | 
-| 6th backup | 3.8  | 8.0  | 16.8 | 22.0 | 
-| 7th backup | 5.1  | 7.8  | 14.3 | 21.6 | 
-| 8th backup | 9.5  | 13.5 | 18.3 | 35.0 | 
-| 9th backup | 4.3  | 9.0  | 15.7 | 24.9 | 
-| 10th backup | 7.9 | 20.2 | 32.2 | 35.0 | 
-| 11th backup | 4.6 | 9.1  | 16.8 | 28.1 | 
-| 12th backup | 7.4 | 12.0 | 21.7 | 37.4 | 
-
-
-For more details and other speed comparison results, please visit https://github.com/gilbertchen/benchmarking.  There you can also find test scripts that you can use to run your own experiments.
-
 ## License
 
 * Free for personal use or commercial trial
-* Non-trial commercial use requires per-user licenses available from [duplicacy.com](https://duplicacy.com/customer) at a cost of $20 per year
+* Non-trial commercial use requires per-computer CLI licenses available from [duplicacy.com](https://duplicacy.com/buy.html) at a cost of $50 per year
+* The computer with a valid commercial license for the GUI version may run the CLI version without a CLI license
+* CLI licenses are not required to restore or manage backups; only the backup command requires valid CLI licenses
 * Modification and redistribution are permitted, but commercial use of derivative works is subject to the same requirements of this license

go.mod

@@ -0,0 +1,78 @@
+module github.com/gilbertchen/duplicacy
+
+go 1.19
+
+require (
+	cloud.google.com/go v0.38.0
+	github.com/aryann/difflib v0.0.0-20170710044230-e206f873d14a
+	github.com/aws/aws-sdk-go v1.30.7
+	github.com/bkaradzic/go-lz4 v1.0.0
+	github.com/gilbertchen/azure-sdk-for-go v14.1.2-0.20180323033227-8fd4663cab7c+incompatible
+	github.com/gilbertchen/cli v1.2.1-0.20160223210219-1de0a1836ce9
+	github.com/gilbertchen/go-dropbox v0.0.0-20230321030224-087ef8db1916
+	github.com/gilbertchen/go-ole v1.2.0
+	github.com/gilbertchen/goamz v0.0.0-20170712012135-eada9f4e8cc2
+	github.com/gilbertchen/gopass v0.0.0-20170109162249-bf9dde6d0d2c
+	github.com/gilbertchen/highwayhash v0.0.0-20221109044721-eeab1f4799d8
+	github.com/gilbertchen/keyring v0.0.0-20221004152639-1661cbebc508
+	github.com/gilbertchen/xattr v0.0.0-20160926155429-68e7a6806b01
+	github.com/hirochachacha/go-smb2 v1.1.0
+	github.com/klauspost/compress v1.16.3
+	github.com/klauspost/reedsolomon v1.9.9
+	github.com/minio/blake2b-simd v0.0.0-20160723061019-3f5f724cb5b1
+	github.com/minio/highwayhash v1.0.2
+	github.com/ncw/swift/v2 v2.0.1
+	github.com/pkg/sftp v1.11.0
+	github.com/pkg/xattr v0.4.1
+	github.com/vmihailenco/msgpack v4.0.4+incompatible
+	golang.org/x/crypto v0.12.0
+	golang.org/x/net v0.10.0
+	golang.org/x/oauth2 v0.0.0-20200107190931-bf48bf16ab8d
+	google.golang.org/api v0.21.0
+	storj.io/uplink v1.12.0
+)
+
+require (
+	github.com/Azure/go-autorest v10.15.5+incompatible // indirect
+	github.com/calebcase/tmpfile v1.0.3 // indirect
+	github.com/dgrijalva/jwt-go v3.2.0+incompatible // indirect
+	github.com/dnaeon/go-vcr v1.2.0 // indirect
+	github.com/flynn/noise v1.0.0 // indirect
+	github.com/geoffgarside/ber v1.1.0 // indirect
+	github.com/goamz/goamz v0.0.0-20180131231218-8b901b531db8 // indirect
+	github.com/godbus/dbus v4.1.0+incompatible // indirect
+	github.com/gogo/protobuf v1.3.2 // indirect
+	github.com/golang/groupcache v0.0.0-20200121045136-8c9f03a8e57e // indirect
+	github.com/golang/protobuf v1.5.0 // indirect
+	github.com/googleapis/gax-go/v2 v2.0.5 // indirect
+	github.com/jmespath/go-jmespath v0.3.0 // indirect
+	github.com/jtolio/eventkit v0.0.0-20221004135224-074cf276595b // indirect
+	github.com/jtolio/noiseconn v0.0.0-20230111204749-d7ec1a08b0b8 // indirect
+	github.com/klauspost/cpuid v1.3.1 // indirect
+	github.com/klauspost/cpuid/v2 v2.0.12 // indirect
+	github.com/kr/fs v0.1.0 // indirect
+	github.com/marstr/guid v1.1.0 // indirect
+	github.com/mmcloughlin/avo v0.0.0-20200803215136-443f81d77104 // indirect
+	github.com/pkg/errors v0.9.1 // indirect
+	github.com/satori/go.uuid v1.2.0 // indirect
+	github.com/segmentio/go-env v1.1.0 // indirect
+	github.com/spacemonkeygo/monkit/v3 v3.0.20-0.20230227152157-d00b379de191 // indirect
+	github.com/vaughan0/go-ini v0.0.0-20130923145212-a98ad7ee00ec // indirect
+	github.com/vivint/infectious v0.0.0-20200605153912-25a574ae18a3 // indirect
+	github.com/zeebo/blake3 v0.2.3 // indirect
+	github.com/zeebo/errs v1.3.0 // indirect
+	go.opencensus.io v0.22.3 // indirect
+	golang.org/x/mod v0.10.0 // indirect
+	golang.org/x/sync v0.3.0 // indirect
+	golang.org/x/sys v0.11.0 // indirect
+	golang.org/x/term v0.11.0 // indirect
+	golang.org/x/text v0.12.0 // indirect
+	golang.org/x/tools v0.9.1 // indirect
+	google.golang.org/appengine v1.6.5 // indirect
+	google.golang.org/genproto v0.0.0-20200409111301-baae70f3302d // indirect
+	google.golang.org/grpc v1.28.1 // indirect
+	google.golang.org/protobuf v1.28.1 // indirect
+	storj.io/common v0.0.0-20230907123639-5fd0608fd947 // indirect
+	storj.io/drpc v0.0.33 // indirect
+	storj.io/picobuf v0.0.2-0.20230906122608-c4ba17033c6c // indirect
+)

go.sum

@@ -0,0 +1,303 @@
+cloud.google.com/go v0.26.0/go.mod h1:aQUYkXzVsufM+DwF1aE+0xfcU+56JwCaLick0ClmMTw=
+cloud.google.com/go v0.34.0/go.mod h1:aQUYkXzVsufM+DwF1aE+0xfcU+56JwCaLick0ClmMTw=
+cloud.google.com/go v0.38.0 h1:ROfEUZz+Gh5pa62DJWXSaonyu3StP6EA6lPEXPI6mCo=
+cloud.google.com/go v0.38.0/go.mod h1:990N+gfupTy94rShfmMCWGDn0LpTmnzTp2qbd1dvSRU=
+github.com/Azure/go-autorest v10.15.5+incompatible h1:vdxx6wM1rVkKt/3niByPVjguoLWkWImOcJNvEykgBzY=
+github.com/Azure/go-autorest v10.15.5+incompatible/go.mod h1:r+4oMnoxhatjLLJ6zxSWATqVooLgysK6ZNox3g/xq24=
+github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
+github.com/aryann/difflib v0.0.0-20170710044230-e206f873d14a h1:pv34s756C4pEXnjgPfGYgdhg/ZdajGhyOvzx8k+23nw=
+github.com/aryann/difflib v0.0.0-20170710044230-e206f873d14a/go.mod h1:DAHtR1m6lCRdSC2Tm3DSWRPvIPr6xNKyeHdqDQSQT+A=
+github.com/aws/aws-sdk-go v1.30.7 h1:IaXfqtioP6p9SFAnNfsqdNczbR5UNbYqvcZUSsCAdTY=
+github.com/aws/aws-sdk-go v1.30.7/go.mod h1:5zCpMtNQVjRREroY7sYe8lOMRSxkhG6MZveU8YkpAk0=
+github.com/bkaradzic/go-lz4 v1.0.0 h1:RXc4wYsyz985CkXXeX04y4VnZFGG8Rd43pRaHsOXAKk=
+github.com/bkaradzic/go-lz4 v1.0.0/go.mod h1:0YdlkowM3VswSROI7qDxhRvJ3sLhlFrRRwjwegp5jy4=
+github.com/calebcase/tmpfile v1.0.3 h1:BZrOWZ79gJqQ3XbAQlihYZf/YCV0H4KPIdM5K5oMpJo=
+github.com/calebcase/tmpfile v1.0.3/go.mod h1:UAUc01aHeC+pudPagY/lWvt2qS9ZO5Zzof6/tIUzqeI=
+github.com/census-instrumentation/opencensus-proto v0.2.1/go.mod h1:f6KPmirojxKA12rnyqOA5BBL4O983OfeGPqjHWSTneU=
+github.com/client9/misspell v0.3.4/go.mod h1:qj6jICC3Q7zFZvVWo7KLAzC3yx5G7kyvSDkc90ppPyw=
+github.com/cncf/udpa/go v0.0.0-20191209042840-269d4d468f6f/go.mod h1:M8M6+tZqaGXZJjfX53e64911xZQV5JYwmTeXPW+k8Sc=
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/dgrijalva/jwt-go v3.2.0+incompatible h1:7qlOGliEKZXTDg6OTjfoBKDXWrumCAMpl/TFQ4/5kLM=
+github.com/dgrijalva/jwt-go v3.2.0+incompatible/go.mod h1:E3ru+11k8xSBh+hMPgOLZmtrrCbhqsmaPHjLKYnJCaQ=
+github.com/dnaeon/go-vcr v1.2.0 h1:zHCHvJYTMh1N7xnV7zf1m1GPBF9Ad0Jk/whtQ1663qI=
+github.com/dnaeon/go-vcr v1.2.0/go.mod h1:R4UdLID7HZT3taECzJs4YgbbH6PIGXB6W/sc5OLb6RQ=
+github.com/dsnet/try v0.0.3 h1:ptR59SsrcFUYbT/FhAbKTV6iLkeD6O18qfIWRml2fqI=
+github.com/envoyproxy/go-control-plane v0.9.0/go.mod h1:YTl/9mNaCwkRvm6d1a2C3ymFceY/DCBVvsKhRF0iEA4=
+github.com/envoyproxy/go-control-plane v0.9.1-0.20191026205805-5f8ba28d4473/go.mod h1:YTl/9mNaCwkRvm6d1a2C3ymFceY/DCBVvsKhRF0iEA4=
+github.com/envoyproxy/go-control-plane v0.9.4/go.mod h1:6rpuAdCZL397s3pYoYcLgu1mIlRU8Am5FuJP05cCM98=
+github.com/envoyproxy/protoc-gen-validate v0.1.0/go.mod h1:iSmxcyjqTsJpI2R4NaDN7+kN2VEUnK/pcBlmesArF7c=
+github.com/flynn/noise v1.0.0 h1:DlTHqmzmvcEiKj+4RYo/imoswx/4r6iBlCMfVtrMXpQ=
+github.com/flynn/noise v1.0.0/go.mod h1:xbMo+0i6+IGbYdJhF31t2eR1BIU0CYc12+BNAKwUTag=
+github.com/geoffgarside/ber v1.1.0 h1:qTmFG4jJbwiSzSXoNJeHcOprVzZ8Ulde2Rrrifu5U9w=
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+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c h1:Hei/4ADfdWqJk1ZMxUNpqntNwaWcugrBjAiHlqqRiVk=
+gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c/go.mod h1:JHkPIbrfpd72SG/EVd6muEfDQjcINNoR0C8j2r3qZ4Q=
+gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
+gopkg.in/yaml.v2 v2.2.8 h1:obN1ZagJSUGI0Ek/LBmuj4SNLPfIny3KsKFopxRdj10=
+gopkg.in/yaml.v2 v2.2.8/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+honnef.co/go/tools v0.0.0-20190102054323-c2f93a96b099/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=
+honnef.co/go/tools v0.0.0-20190106161140-3f1c8253044a/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=
+honnef.co/go/tools v0.0.0-20190523083050-ea95bdfd59fc/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=
+rsc.io/pdf v0.1.1/go.mod h1:n8OzWcQ6Sp37PL01nO98y4iUCRdTGarVfzxY20ICaU4=
+storj.io/common v0.0.0-20230907123639-5fd0608fd947 h1:X75A5hX1nFjQH8GIvei4T1LNQTLa++bsDKMxXxfPHE8=
+storj.io/common v0.0.0-20230907123639-5fd0608fd947/go.mod h1:FMVOxf2+SgsmfjxwFCM1MZCKwXis4U7l22M/6nIhIas=
+storj.io/drpc v0.0.33 h1:yCGZ26r66ZdMP0IcTYsj7WDAUIIjzXk6DJhbhvt9FHI=
+storj.io/drpc v0.0.33/go.mod h1:vR804UNzhBa49NOJ6HeLjd2H3MakC1j5Gv8bsOQT6N4=
+storj.io/picobuf v0.0.2-0.20230906122608-c4ba17033c6c h1:or/DtG5uaZpzimL61ahlgAA+MTYn/U3txz4fe+XBFUg=
+storj.io/picobuf v0.0.2-0.20230906122608-c4ba17033c6c/go.mod h1:JCuc3C0gzCJHQ4J6SOx/Yjg+QTpX0D+Fvs5H46FETCk=
+storj.io/uplink v1.12.0 h1:rTODjbKRo/lzz5Hp0isjoRfqDcH7kJg6aujD2M9v9Ro=
+storj.io/uplink v1.12.0/go.mod h1:nMAuoWi5AHio+8NQa33VRzCiRg0B0UhYKuT0a0CdXOg=

integration_tests/copy_test.sh

@@ -0,0 +1,31 @@
+#!/bin/bash
+
+
+. ./test_functions.sh
+
+fixture
+
+pushd ${TEST_REPO}
+${DUPLICACY} init integration-tests $TEST_STORAGE -c 1k
+${DUPLICACY} add -copy default secondary integration-tests $SECONDARY_STORAGE
+add_file file1
+add_file file2
+${DUPLICACY} backup 
+${DUPLICACY} copy -from default -to secondary
+add_file file3
+add_file file4
+${DUPLICACY} backup 
+${DUPLICACY} copy -from default -to secondary
+${DUPLICACY} check --files -stats -storage default
+${DUPLICACY} check --files -stats -storage secondary
+# Prune revisions from default storage
+${DUPLICACY} -d -v -log prune -r 1-2 -exclusive -exhaustive -storage default
+# Copy snapshot revisions from secondary back to default
+${DUPLICACY} copy -from secondary -to default
+# Check snapshot revisions again to make sure we're ok!
+${DUPLICACY} check --files -stats -storage default
+${DUPLICACY} check --files -stats -storage secondary
+# Check for orphaned or missing chunks
+${DUPLICACY} prune -exhaustive -exclusive -storage default
+${DUPLICACY} prune -exhaustive -exclusive -storage secondary
+popd

src/duplicacy_acdclient.go

@@ -5,16 +5,16 @@
 package duplicacy
 
 import (
-    "fmt"
-    "time"
 	"bytes"
-    "sync"
-    "io/ioutil"
 	"encoding/json"
+	"fmt"
 	"io"
-    "net/http"
-    "mime/multipart"
+	"io/ioutil"
 	"math/rand"
+	"mime/multipart"
+	"net/http"
+	"sync"
+	"time"
 
 	"golang.org/x/oauth2"
 )
@@ -29,6 +29,7 @@ func (err ACDError) Error() string {
 }
 
 var ACDRefreshTokenURL = "https://duplicacy.com/acd_refresh"
+
 type ACDClient struct {
 	HTTPClient *http.Client
 
@@ -42,7 +43,6 @@ type ACDClient struct {
 	TestMode bool
 }
 
-
 func NewACDClient(tokenFile string) (*ACDClient, error) {
 
 	description, err := ioutil.ReadFile(tokenFile)
@@ -69,7 +69,7 @@ func NewACDClient(tokenFile string) (*ACDClient, error) {
 
 func (client *ACDClient) call(url string, method string, input interface{}, contentType string) (io.ReadCloser, int64, error) {
 
-    LOG_DEBUG("ACD_CALL", "Calling %s", url)
+	//LOG_DEBUG("ACD_CALL", "%s %s", method, url)
 
 	var response *http.Response
 
@@ -256,7 +256,7 @@ type ACDListEntriesOutput struct {
 	Entries   []ACDEntry `json:"data"`
 }
 
-func (client *ACDClient) ListEntries(parentID string, listFiles bool) ([]ACDEntry, error) {
+func (client *ACDClient) ListEntries(parentID string, listFiles bool, listDirectories bool) ([]ACDEntry, error) {
 
 	startToken := ""
 
@@ -264,20 +264,22 @@ func (client *ACDClient) ListEntries(parentID string, listFiles bool) ([]ACDEntr
 
 	for {
 
-        url := client.MetadataURL + "nodes/" + parentID + "/children?filters="
+		url := client.MetadataURL + "nodes/" + parentID + "/children?"
 
-        if listFiles {
-            url += "kind:FILE"
-        } else {
-            url += "kind:FOLDER"
+		if listFiles && !listDirectories {
+			url += "filters=kind:FILE&"
+		} else if !listFiles && listDirectories {
+			url += "filters=kind:FOLDER&"
 		}
 
 		if startToken != "" {
-            url += "&startToken=" + startToken
+			url += "startToken=" + startToken + "&"
 		}
 
 		if client.TestMode {
-            url += "&limit=8"
+			url += "limit=8"
+		} else {
+			url += "limit=200"
 		}
 
 		readCloser, _, err := client.call(url, "GET", 0, "")

src/duplicacy_acdclient_test.go

@@ -1,153 +0,0 @@
-// Copyright (c) Acrosync LLC. All rights reserved.
-// Free for personal use and commercial trial
-// Commercial use requires per-user licenses available from https://duplicacy.com
-
-package duplicacy
-
-import (
-    "io"
-    "fmt"
-    "testing"
-    "crypto/sha256"
-    "encoding/hex"
-
-    crypto_rand "crypto/rand"
-    "math/rand"
-)
-
-func TestACDClient(t *testing.T) {
-
-    acdClient, err := NewACDClient("acd-token.json")
-    if err != nil {
-        t.Errorf("Failed to create the ACD client: %v", err)
-        return
-    }
-
-    acdClient.TestMode = true
-
-    rootID, _, _, err := acdClient.ListByName("", "")
-    if err != nil {
-        t.Errorf("Failed to get the root node: %v", err)
-        return
-    }
-
-    if rootID == "" {
-        t.Errorf("No root node")
-        return
-    }
-
-    testID, _, _, err := acdClient.ListByName(rootID, "test")
-    if err != nil {
-        t.Errorf("Failed to list the test directory: %v", err)
-        return
-    }
-    if testID == "" {
-        testID, err = acdClient.CreateDirectory(rootID, "test")
-        if err != nil {
-            t.Errorf("Failed to create the test directory: %v", err)
-            return
-        }
-    }
-
-    test1ID, _, _, err := acdClient.ListByName(testID, "test1")
-    if err != nil {
-        t.Errorf("Failed to list the test1 directory: %v", err)
-        return
-    }
-    if test1ID == "" {
-        test1ID, err = acdClient.CreateDirectory(testID, "test1")
-        if err != nil {
-            t.Errorf("Failed to create the test1 directory: %v", err)
-            return
-        }
-    }
-
-    test2ID, _, _, err := acdClient.ListByName(testID, "test2")
-    if err != nil {
-        t.Errorf("Failed to list the test2 directory: %v", err)
-        return
-    }
-    if test2ID == "" {
-        test2ID, err = acdClient.CreateDirectory(testID, "test2")
-        if err != nil {
-            t.Errorf("Failed to create the test2 directory: %v", err)
-            return
-        }
-    }
-
-    fmt.Printf("test1: %s, test2: %s\n", test1ID, test2ID)
-
-    numberOfFiles := 20
-    maxFileSize := 64 * 1024
-
-    for i := 0; i < numberOfFiles; i++ {
-        content := make([]byte, rand.Int() % maxFileSize + 1)
-        _, err = crypto_rand.Read(content)
-        if err != nil {
-            t.Errorf("Error generating random content: %v", err)
-            return
-        }
-
-        hasher := sha256.New()
-        hasher.Write(content)
-        filename := hex.EncodeToString(hasher.Sum(nil))
-
-        fmt.Printf("file: %s\n", filename)
-
-        _, err = acdClient.UploadFile(test1ID, filename, content, 100)
-        if err != nil {
-            /*if e, ok := err.(ACDError); !ok || e.Status != 409 */ {
-                t.Errorf("Failed to upload the file %s: %v", filename, err)
-                return
-            }
-        }
-    }
-
-    entries, err := acdClient.ListEntries(test1ID, true)
-    if err != nil {
-        t.Errorf("Error list randomly generated files: %v", err)
-        return
-    }
-
-    for _, entry := range entries {
-        err = acdClient.MoveFile(entry.ID, test1ID, test2ID)
-        if err != nil {
-            t.Errorf("Failed to move %s: %v", entry.Name, err)
-            return
-        }
-    }
-
-    entries, err = acdClient.ListEntries(test2ID, true)
-    if err != nil {
-        t.Errorf("Error list randomly generated files: %v", err)
-        return
-    }
-
-    for _, entry := range entries {
-        readCloser, _, err := acdClient.DownloadFile(entry.ID)
-        if err != nil {
-            t.Errorf("Error downloading file %s: %v", entry.Name, err)
-            return
-        }
-
-        hasher := sha256.New()
-        io.Copy(hasher, readCloser)
-        hash := hex.EncodeToString(hasher.Sum(nil))
-
-        if hash != entry.Name {
-            t.Errorf("File %s, hash %s", entry.Name, hash)
-        }
-
-        readCloser.Close()
-    }
-
-    for _, entry := range entries {
-
-        err = acdClient.DeleteFile(entry.ID)
-        if err != nil {
-            t.Errorf("Failed to delete the file %s: %v", entry.Name, err)
-            return
-        }
-    }
-
-}

src/duplicacy_acdstorage.go

@@ -9,10 +9,11 @@ import (
 	"path"
 	"strings"
 	"sync"
+	"time"
 )
 
 type ACDStorage struct {
-    RateLimitedStorage
+	StorageBase
 
 	client          *ACDClient
 	idCache         map[string]string
@@ -35,11 +36,13 @@ func CreateACDStorage(tokenFile string, storagePath string, threads int) (storag
 		numberOfThreads: threads,
 	}
 
-    storagePathID, _, _, err := storage.getIDFromPath(0, storagePath)
+	storagePathID, err := storage.getIDFromPath(0, storagePath, false)
 	if err != nil {
 		return nil, err
 	}
 
+	// Set 'storagePath' as the root of the storage and clean up the id cache accordingly
+	storage.idCache = make(map[string]string)
 	storage.idCache[""] = storagePathID
 
 	for _, dir := range []string{"chunks", "fossils", "snapshots"} {
@@ -48,18 +51,18 @@ func CreateACDStorage(tokenFile string, storagePath string, threads int) (storag
 			return nil, err
 		}
 		if dirID == "" {
-            dirID, err = client.CreateDirectory(storagePathID, dir)
 			if err != nil {
 				return nil, err
 			}
 		} else if !isDir {
-            return nil, fmt.Errorf("%s/%s is not a directory", storagePath + "/" + dir)
+			return nil, fmt.Errorf("%s is not a directory", storagePath+"/"+dir)
 		}
 		storage.idCache[dir] = dirID
 	}
 
+	storage.DerivedStorage = storage
+	storage.SetDefaultNestingLevels([]int{0}, 0)
 	return storage, nil
-
 }
 
 func (storage *ACDStorage) getPathID(path string) string {
@@ -88,43 +91,90 @@ func (storage *ACDStorage) deletePathID(path string) {
 	storage.idCacheLock.Unlock()
 }
 
-
-func (storage *ACDStorage) convertFilePath(filePath string) (string) {
+// convertFilePath converts the path for a fossil in the form of 'chunks/id.fsl' to 'fossils/id'.  This is because
+// ACD doesn't support file renaming. Instead, it only allows one file to be moved from one directory to another.
+// By adding a layer of path conversion we're pretending that we can rename between 'chunks/id' and 'chunks/id.fsl'
+func (storage *ACDStorage) convertFilePath(filePath string) string {
 	if strings.HasPrefix(filePath, "chunks/") && strings.HasSuffix(filePath, ".fsl") {
 		return "fossils/" + filePath[len("chunks/"):len(filePath)-len(".fsl")]
 	}
 	return filePath
 }
 
-func (storage *ACDStorage) getIDFromPath(threadIndex int, path string) (fileID string, isDir bool, size int64, err error) {
+// getIDFromPath returns the id of the given path.  If 'createDirectories' is true, create the given path and all its
+// parent directories if they don't exist.  Note that if 'createDirectories' is false, it may return an empty 'fileID'
+// if the file doesn't exist.
+func (storage *ACDStorage) getIDFromPath(threadIndex int, filePath string, createDirectories bool) (fileID string, err error) {
+
+	if fileID, ok := storage.findPathID(filePath); ok {
+		return fileID, nil
+	}
 
 	parentID, ok := storage.findPathID("")
 	if !ok {
-        parentID, isDir, size, err = storage.client.ListByName("", "")
+		parentID, _, _, err = storage.client.ListByName("", "")
 		if err != nil {
-            return "", false, 0, err
+			return "", err
 		}
+		storage.savePathID("", parentID)
 	}
 
-    names := strings.Split(path, "/")
+	names := strings.Split(filePath, "/")
+	current := ""
 	for i, name := range names {
-        parentID, isDir, _, err = storage.client.ListByName(parentID, name)
+
+		current = path.Join(current, name)
+		fileID, ok := storage.findPathID(current)
+		if ok {
+			parentID = fileID
+			continue
+		}
+		isDir := false
+		fileID, isDir, _, err = storage.client.ListByName(parentID, name)
 		if err != nil {
-            return "", false, 0, err
+			return "", err
 		}
-        if parentID == "" {
-            if i == len(names) - 1 {
-                return "", false, 0, nil
+		if fileID == "" {
+			if !createDirectories {
+				return "", nil
+			}
+			// Create the current directory
+			fileID, err = storage.client.CreateDirectory(parentID, name)
+			if err != nil {
+				// Check if the directory has been created by another thread
+				if e, ok := err.(ACDError); !ok || e.Status != 409 {
+					return "", fmt.Errorf("Failed to create directory '%s': %v", current, err)
+				}
+				// A 409 means the directory may have already created by another thread.  Wait 10 seconds
+				// until we seed the directory.
+				for i := 0; i < 10; i++ {
+					var createErr error
+					fileID, isDir, _, createErr = storage.client.ListByName(parentID, name)
+					if createErr != nil {
+						return "", createErr
+					}
+					if fileID == "" {
+						time.Sleep(time.Second)
 					} else {
-                return "", false, 0, fmt.Errorf("File path '%s' does not exist", path)
+						break
 					}
 				}
+				if fileID == "" {
+					return "", fmt.Errorf("All attempts to create directory '%s' failed: %v", current, err)
+				}
+			} else {
+				isDir = true
+			}
+		} else {
+			storage.savePathID(current, fileID)
+		}
 		if i != len(names)-1 && !isDir {
-            return "", false, 0, fmt.Errorf("Invalid path %s", path)
+			return "", fmt.Errorf("Path '%s' is not a directory", current)
 		}
+		parentID = fileID
 	}
 
-    return parentID, isDir, size, err
+	return parentID, nil
 }
 
 // ListFiles return the list of files and subdirectories under 'dir' (non-recursively)
@@ -137,7 +187,7 @@ func (storage *ACDStorage) ListFiles(threadIndex int, dir string) ([]string, []i
 
 	if dir == "snapshots" {
 
-        entries, err := storage.client.ListEntries(storage.getPathID(dir), false)
+		entries, err := storage.client.ListEntries(storage.getPathID(dir), false, true)
 		if err != nil {
 			return nil, nil, err
 		}
@@ -160,9 +210,10 @@ func (storage *ACDStorage) ListFiles(threadIndex int, dir string) ([]string, []i
 			if pathID == "" {
 				return nil, nil, nil
 			}
+			storage.savePathID(dir, pathID)
 		}
 
-        entries, err := storage.client.ListEntries(pathID, true)
+		entries, err := storage.client.ListEntries(pathID, true, false)
 		if err != nil {
 			return nil, nil, err
 		}
@@ -177,22 +228,33 @@ func (storage *ACDStorage) ListFiles(threadIndex int, dir string) ([]string, []i
 	} else {
 		files := []string{}
 		sizes := []int64{}
-        for _, parent := range []string {"chunks", "fossils" } {
-            entries, err := storage.client.ListEntries(storage.getPathID(parent), true)
+		parents := []string{"chunks", "fossils"}
+		for i := 0; i < len(parents); i++ {
+			parent := parents[i]
+			pathID, ok := storage.findPathID(parent)
+			if !ok {
+				continue
+			}
+			entries, err := storage.client.ListEntries(pathID, true, true)
 			if err != nil {
 				return nil, nil, err
 			}
-
-
 			for _, entry := range entries {
+				if entry.Kind != "FOLDER" {
 					name := entry.Name
-                if parent == "fossils" {
-                    name += ".fsl"
+					if strings.HasPrefix(parent, "fossils") {
+						name = parent + "/" + name + ".fsl"
+						name = name[len("fossils/"):]
+					} else {
+						name = parent + "/" + name
+						name = name[len("chunks/"):]
 					}
-
-                storage.savePathID(parent + "/" + entry.Name, entry.ID)
 					files = append(files, name)
 					sizes = append(sizes, entry.Size)
+				} else {
+					parents = append(parents, parent+"/"+entry.Name)
+				}
+				storage.savePathID(parent+"/"+entry.Name, entry.ID)
 			}
 		}
 		return files, sizes, nil
@@ -203,18 +265,14 @@ func (storage *ACDStorage) ListFiles(threadIndex int, dir string) ([]string, []i
 // DeleteFile deletes the file or directory at 'filePath'.
 func (storage *ACDStorage) DeleteFile(threadIndex int, filePath string) (err error) {
 	filePath = storage.convertFilePath(filePath)
-    fileID, ok := storage.findPathID(filePath)
-    if !ok {
-        fileID, _, _, err = storage.getIDFromPath(threadIndex, filePath)
+	fileID, err := storage.getIDFromPath(threadIndex, filePath, false)
 	if err != nil {
 		return err
 	}
 	if fileID == "" {
-            LOG_TRACE("ACD_STORAGE", "File %s has disappeared before deletion", filePath)
+		LOG_TRACE("ACD_STORAGE", "File '%s' to be deleted does not exist", filePath)
 		return nil
 	}
-        storage.savePathID(filePath, fileID)
-    }
 
 	err = storage.client.DeleteFile(fileID)
 	if e, ok := err.(ACDError); ok && e.Status == 409 {
@@ -234,11 +292,19 @@ func (storage *ACDStorage) MoveFile(threadIndex int, from string, to string) (er
 		return fmt.Errorf("Attempting to rename file %s with unknown id", from)
 	}
 
-    fromParentID := storage.getPathID("chunks")
-    toParentID := storage.getPathID("fossils")
+	fromParent := path.Dir(from)
+	fromParentID, err := storage.getIDFromPath(threadIndex, fromParent, false)
+	if err != nil {
+		return fmt.Errorf("Failed to retrieve the id of the parent directory '%s': %v", fromParent, err)
+	}
+	if fromParentID == "" {
+		return fmt.Errorf("The parent directory '%s' does not exist", fromParent)
+	}
 
-    if strings.HasPrefix(from, "fossils") {
-        fromParentID, toParentID = toParentID, fromParentID
+	toParent := path.Dir(to)
+	toParentID, err := storage.getIDFromPath(threadIndex, toParent, true)
+	if err != nil {
+		return fmt.Errorf("Failed to retrieve the id of the parent directory '%s': %v", toParent, err)
 	}
 
 	err = storage.client.MoveFile(fileID, fromParentID, toParentID)
@@ -263,13 +329,17 @@ func (storage *ACDStorage) CreateDirectory(threadIndex int, dir string) (err err
 		dir = dir[:len(dir)-1]
 	}
 
-    if dir == "chunks" || dir == "snapshots" {
-        return nil
+	parentPath := path.Dir(dir)
+	if parentPath == "." {
+		parentPath = ""
+	}
+	parentID, ok := storage.findPathID(parentPath)
+	if !ok {
+		return fmt.Errorf("Path directory '%s' has unknown id", parentPath)
 	}
 
-    if strings.HasPrefix(dir, "snapshots/") {
-        name := dir[len("snapshots/"):]
-        dirID, err := storage.client.CreateDirectory(storage.getPathID("snapshots"), name)
+	name := path.Base(dir)
+	dirID, err := storage.client.CreateDirectory(parentID, name)
 	if err != nil {
 		if e, ok := err.(ACDError); ok && e.Status == 409 {
 			return nil
@@ -278,9 +348,6 @@ func (storage *ACDStorage) CreateDirectory(threadIndex int, dir string) (err err
 		}
 	}
 	storage.savePathID(dir, dirID)
-        return nil
-
-    }
 
 	return nil
 }
@@ -293,8 +360,21 @@ func (storage *ACDStorage) GetFileInfo(threadIndex int, filePath string) (exist
 	}
 
 	filePath = storage.convertFilePath(filePath)
-    fileID := ""
-    fileID, isDir, size, err = storage.getIDFromPath(threadIndex, filePath)
+
+	parentPath := path.Dir(filePath)
+	if parentPath == "." {
+		parentPath = ""
+	}
+	parentID, err := storage.getIDFromPath(threadIndex, parentPath, false)
+	if err != nil {
+		return false, false, 0, err
+	}
+	if parentID == "" {
+		return false, false, 0, nil
+	}
+
+	name := path.Base(filePath)
+	fileID, isDir, size, err := storage.client.ListByName(parentID, name)
 	if err != nil {
 		return false, false, 0, err
 	}
@@ -302,44 +382,19 @@ func (storage *ACDStorage) GetFileInfo(threadIndex int, filePath string) (exist
 		return false, false, 0, nil
 	}
 
+	storage.savePathID(filePath, fileID)
 	return true, isDir, size, nil
 }
 
-// FindChunk finds the chunk with the specified id.  If 'isFossil' is true, it will search for chunk files with
-// the suffix '.fsl'.
-func (storage *ACDStorage) FindChunk(threadIndex int, chunkID string, isFossil bool) (filePath string, exist bool, size int64, err error) {
-    parentID := ""
-    filePath = "chunks/" + chunkID
-    realPath := filePath
-    if isFossil {
-        parentID = storage.getPathID("fossils")
-        filePath += ".fsl"
-        realPath = "fossils/" + chunkID + ".fsl"
-    } else {
-        parentID = storage.getPathID("chunks")
-    }
-
-    fileID := ""
-    fileID, _, size, err = storage.client.ListByName(parentID, chunkID)
-    if fileID != "" {
-        storage.savePathID(realPath, fileID)
-    }
-    return filePath, fileID != "", size, err
-}
-
 // DownloadFile reads the file at 'filePath' into the chunk.
 func (storage *ACDStorage) DownloadFile(threadIndex int, filePath string, chunk *Chunk) (err error) {
-    fileID, ok := storage.findPathID(filePath)
-    if !ok {
-        fileID, _, _, err = storage.getIDFromPath(threadIndex, filePath)
+	fileID, err := storage.getIDFromPath(threadIndex, filePath, false)
 	if err != nil {
 		return err
 	}
 	if fileID == "" {
 		return fmt.Errorf("File path '%s' does not exist", filePath)
 	}
-        storage.savePathID(filePath, fileID)
-    }
 
 	readCloser, _, err := storage.client.DownloadFile(fileID)
 	if err != nil {
@@ -355,23 +410,17 @@ func (storage *ACDStorage) DownloadFile(threadIndex int, filePath string, chunk
 // UploadFile writes 'content' to the file at 'filePath'.
 func (storage *ACDStorage) UploadFile(threadIndex int, filePath string, content []byte) (err error) {
 	parent := path.Dir(filePath)
-
 	if parent == "." {
 		parent = ""
 	}
 
-    parentID, ok := storage.findPathID(parent)
-
-    if !ok {
-        parentID, _, _, err = storage.getIDFromPath(threadIndex, parent)
+	parentID, err := storage.getIDFromPath(threadIndex, parent, true)
 	if err != nil {
 		return err
 	}
 	if parentID == "" {
 		return fmt.Errorf("File path '%s' does not exist", parent)
 	}
-        storage.savePathID(parent, parentID)
-    }
 
 	fileID, err := storage.client.UploadFile(parentID, path.Base(filePath), content, storage.UploadRateLimit/storage.numberOfThreads)
 	if err == nil {
@@ -389,16 +438,16 @@ func (storage *ACDStorage) UploadFile(threadIndex int, filePath string, content
 
 // If a local snapshot cache is needed for the storage to avoid downloading/uploading chunks too often when
 // managing snapshots.
-func (storage *ACDStorage) IsCacheNeeded() (bool) { return true }
+func (storage *ACDStorage) IsCacheNeeded() bool { return true }
 
 // If the 'MoveFile' method is implemented.
-func (storage *ACDStorage) IsMoveFileImplemented() (bool) { return true }
+func (storage *ACDStorage) IsMoveFileImplemented() bool { return true }
 
 // If the storage can guarantee strong consistency.
-func (storage *ACDStorage) IsStrongConsistent() (bool) { return true }
+func (storage *ACDStorage) IsStrongConsistent() bool { return true }
 
 // If the storage supports fast listing of files names.
-func (storage *ACDStorage) IsFastListing() (bool) { return true }
+func (storage *ACDStorage) IsFastListing() bool { return true }
 
 // Enable the test mode.
 func (storage *ACDStorage) EnableTestMode() {}

src/duplicacy_azurestorage.go

@@ -12,16 +12,15 @@ import (
 )
 
 type AzureStorage struct {
-    RateLimitedStorage
+	StorageBase
 
-    clients []*storage.BlobStorageClient
-    container string
+	containers []*storage.Container
 }
 
 func CreateAzureStorage(accountName string, accountKey string,
-                        container string, threads int) (azureStorage *AzureStorage, err error) {
+	containerName string, threads int) (azureStorage *AzureStorage, err error) {
 
-    var clients []*storage.BlobStorageClient
+	var containers []*storage.Container
 	for i := 0; i < threads; i++ {
 
 		client, err := storage.NewBasicClient(accountName, accountKey)
@@ -31,23 +30,25 @@ func CreateAzureStorage(accountName string, accountKey string,
 		}
 
 		blobService := client.GetBlobService()
-        clients = append(clients, &blobService)
+		container := blobService.GetContainerReference(containerName)
+		containers = append(containers, container)
 	}
 
-    exist, err := clients[0].ContainerExists(container)
+	exist, err := containers[0].Exists()
 	if err != nil {
 		return nil, err
 	}
 
 	if !exist {
-        return nil, fmt.Errorf("container %s does not exist", container)
+		return nil, fmt.Errorf("container %s does not exist", containerName)
 	}
 
 	azureStorage = &AzureStorage{
-        clients: clients,
-        container: container,
+		containers: containers,
 	}
 
+	azureStorage.DerivedStorage = azureStorage
+	azureStorage.SetDefaultNestingLevels([]int{0}, 0)
 	return
 }
 
@@ -77,7 +78,7 @@ func (azureStorage *AzureStorage) ListFiles(threadIndex int, dir string) (files
 
 	for {
 
-        results, err := azureStorage.clients[threadIndex].ListBlobs(azureStorage.container, parameters)
+		results, err := azureStorage.containers[threadIndex].ListBlobs(parameters)
 		if err != nil {
 			return nil, nil, err
 		}
@@ -103,7 +104,7 @@ func (azureStorage *AzureStorage) ListFiles(threadIndex int, dir string) (files
 
 	if dir == "snapshots/" {
 
-        for subDir, _ := range subDirs {
+		for subDir := range subDirs {
 			files = append(files, subDir)
 		}
 
@@ -115,14 +116,15 @@ func (azureStorage *AzureStorage) ListFiles(threadIndex int, dir string) (files
 
 // DeleteFile deletes the file or directory at 'filePath'.
 func (storage *AzureStorage) DeleteFile(threadIndex int, filePath string) (err error) {
-    _, err = storage.clients[threadIndex].DeleteBlobIfExists(storage.container, filePath)
+	_, err = storage.containers[threadIndex].GetBlobReference(filePath).DeleteIfExists(nil)
 	return err
 }
 
 // MoveFile renames the file.
 func (storage *AzureStorage) MoveFile(threadIndex int, from string, to string) (err error) {
-    source := storage.clients[threadIndex].GetBlobURL(storage.container, from)
-    err = storage.clients[threadIndex].CopyBlob(storage.container, to, source)
+	source := storage.containers[threadIndex].GetBlobReference(from)
+	destination := storage.containers[threadIndex].GetBlobReference(to)
+	err = destination.Copy(source.GetURL(), nil)
 	if err != nil {
 		return err
 	}
@@ -136,7 +138,8 @@ func (storage *AzureStorage) CreateDirectory(threadIndex int, dir string) (err e
 
 // GetFileInfo returns the information about the file or directory at 'filePath'.
 func (storage *AzureStorage) GetFileInfo(threadIndex int, filePath string) (exist bool, isDir bool, size int64, err error) {
-    properties, err := storage.clients[threadIndex].GetBlobProperties(storage.container, filePath)
+	blob := storage.containers[threadIndex].GetBlobReference(filePath)
+	err = blob.GetProperties(nil)
 	if err != nil {
 		if strings.Contains(err.Error(), "404") {
 			return false, false, 0, nil
@@ -145,58 +148,54 @@ func (storage *AzureStorage) GetFileInfo(threadIndex int, filePath string) (exis
 		}
 	}
 
-    return true, false, properties.ContentLength, nil
-}
-
-// FindChunk finds the chunk with the specified id.  If 'isFossil' is true, it will search for chunk files with
-// the suffix '.fsl'.
-func (storage *AzureStorage) FindChunk(threadIndex int, chunkID string, isFossil bool) (filePath string, exist bool, size int64, err error) {
-    filePath = "chunks/" + chunkID
-    if isFossil {
-        filePath += ".fsl"
-    }
-
-    exist, _, size, err = storage.GetFileInfo(threadIndex, filePath)
-
-    if err != nil {
-        return "", false, 0, err
-    } else {
-        return filePath, exist, size, err
-    }
+	return true, false, blob.Properties.ContentLength, nil
 }
 
 // DownloadFile reads the file at 'filePath' into the chunk.
 func (storage *AzureStorage) DownloadFile(threadIndex int, filePath string, chunk *Chunk) (err error) {
-    readCloser, err := storage.clients[threadIndex].GetBlob(storage.container, filePath)
+	readCloser, err := storage.containers[threadIndex].GetBlobReference(filePath).Get(nil)
 	if err != nil {
 		return err
 	}
 
 	defer readCloser.Close()
 
-    _, err = RateLimitedCopy(chunk, readCloser, storage.DownloadRateLimit / len(storage.clients))
+	_, err = RateLimitedCopy(chunk, readCloser, storage.DownloadRateLimit/len(storage.containers))
 	return err
 }
 
 // UploadFile writes 'content' to the file at 'filePath'.
 func (storage *AzureStorage) UploadFile(threadIndex int, filePath string, content []byte) (err error) {
-   reader := CreateRateLimitedReader(content, storage.UploadRateLimit / len(storage.clients))
-   return storage.clients[threadIndex].CreateBlockBlobFromReader(storage.container, filePath, uint64(len(content)), reader, nil)
+
+	tries := 0
+
+	for {
+		reader := CreateRateLimitedReader(content, storage.UploadRateLimit/len(storage.containers))
+		blob := storage.containers[threadIndex].GetBlobReference(filePath)
+		err = blob.CreateBlockBlobFromReader(reader, nil)
+
+		if err == nil || !strings.Contains(err.Error(), "write: broken pipe") || tries >= 3 {
+			return err
+		}
+
+		LOG_INFO("AZURE_RETRY", "Connection unexpectedly terminated: %v; retrying", err)
+		tries++
+	}
 
 }
 
 // If a local snapshot cache is needed for the storage to avoid downloading/uploading chunks too often when
 // managing snapshots.
-func (storage *AzureStorage) IsCacheNeeded() (bool) { return true }
+func (storage *AzureStorage) IsCacheNeeded() bool { return true }
 
 // If the 'MoveFile' method is implemented.
-func (storage *AzureStorage)  IsMoveFileImplemented() (bool) { return true }
+func (storage *AzureStorage) IsMoveFileImplemented() bool { return true }
 
 // If the storage can guarantee strong consistency.
-func (storage *AzureStorage) IsStrongConsistent() (bool) { return true }
+func (storage *AzureStorage) IsStrongConsistent() bool { return true }
 
 // If the storage supports fast listing of files names.
-func (storage *AzureStorage) IsFastListing() (bool) { return true }
+func (storage *AzureStorage) IsFastListing() bool { return true }
 
 // Enable the test mode.
 func (storage *AzureStorage) EnableTestMode() {}

src/duplicacy_b2client.go

@@ -5,19 +5,22 @@
 package duplicacy
 
 import (
+	"io"
+	"os"
 	"fmt"
-    "time"
 	"bytes"
+	"time"
+	"sync"
 	"strconv"
+	"strings"
+	"net/url"
+	"net/http"
+	"math/rand"
 	"io/ioutil"
+	"crypto/sha1"
+	"encoding/hex"
 	"encoding/json"
 	"encoding/base64"
-    "encoding/hex"
-    "io"
-    "net/http"
-    "strings"
-    "crypto/sha1"
-    "math/rand"
 )
 
 type B2Error struct {
@@ -39,86 +42,173 @@ var B2AuthorizationURL = "https://api.backblazeb2.com/b2api/v1/b2_authorize_acco
 
 type B2Client struct {
 	HTTPClient         *http.Client
+
 	AccountID          string
+	ApplicationKeyID   string
 	ApplicationKey     string
+	BucketName         string
+	BucketID           string
+	StorageDir         string
+
+	Lock               sync.Mutex
 	AuthorizationToken string
 	APIURL             string
 	DownloadURL        string
-    BucketName          string
-    BucketID            string
+	IsAuthorized       bool
 
-    UploadURL           string
-    UploadToken         string
+	UploadURLs         []string
+	UploadTokens       []string
 
+	Threads            int
+	MaximumRetries     int
 	TestMode           bool
 
+	LastAuthorizationTime int64
+}
+
+// URL encode the given path but keep the slashes intact
+func B2Escape(path string) string {
+	var components []string
+	for _, c := range strings.Split(path, "/") {
+		components = append(components, url.QueryEscape(c))
+	}
+	return strings.Join(components, "/")
+}
+
+func NewB2Client(applicationKeyID string, applicationKey string, downloadURL string, storageDir string, threads int) *B2Client {
+
+	for storageDir != "" && storageDir[0] == '/' {
+		storageDir = storageDir[1:]
+	}
+
+	if storageDir != "" && storageDir[len(storageDir) - 1] != '/' {
+		storageDir += "/"
+	}
+
+	maximumRetries := 15
+	if value, found := os.LookupEnv("DUPLICACY_B2_RETRIES"); found && value != "" {
+		maximumRetries, _ = strconv.Atoi(value)
+		LOG_INFO("B2_RETRIES", "Setting maximum retries for B2 to %d", maximumRetries)
 	}
 
-func NewB2Client(accountID string, applicationKey string) *B2Client {
 	client := &B2Client{
 		HTTPClient:       http.DefaultClient,
-        AccountID: accountID,
+		ApplicationKeyID: applicationKeyID,
 		ApplicationKey:   applicationKey,
+		DownloadURL:      downloadURL,
+		StorageDir:       storageDir,
+		UploadURLs:       make([]string, threads),
+		UploadTokens:     make([]string, threads),
+		Threads:          threads,
+		MaximumRetries:   maximumRetries,
 	}
 	return client
 }
 
-func (client *B2Client) retry(backoff int, response *http.Response) int {
+func (client *B2Client) getAPIURL() string {
+	client.Lock.Lock()
+	defer client.Lock.Unlock()
+	return client.APIURL
+}
+
+func (client *B2Client) getDownloadURL() string {
+	client.Lock.Lock()
+	defer client.Lock.Unlock()
+	return client.DownloadURL
+}
+
+func (client *B2Client) retry(retries int, response *http.Response) int {
 	if response != nil {
 		if backoffList, found := response.Header["Retry-After"]; found && len(backoffList) > 0 {
 			retryAfter, _ := strconv.Atoi(backoffList[0])
 			if retryAfter >= 1 {
 				time.Sleep(time.Duration(retryAfter) * time.Second)
-                return 0
+				return 1
 			}
 		}
 	}
-    if backoff == 0 {
-        backoff = 1
-    } else {
-        backoff *= 2
-    }
-    time.Sleep(time.Duration(backoff) * time.Second)
-    return backoff
-}
 
-func (client *B2Client) call(url string, input interface{}) (io.ReadCloser, int64, error) {
+	if retries >= client.MaximumRetries + 1 {
+		return 0
+	}
+	retries++
+	delay := 1 << uint(retries)
+	if delay > 64 {
+		delay = 64
+	}
+	delayInSeconds := (rand.Float32() + 1.0) * float32(delay) / 2.0
+
+	time.Sleep(time.Duration(delayInSeconds) * time.Second)
+	return retries
+}
+
+func (client *B2Client) call(threadIndex int, requestURL string, method string, requestHeaders map[string]string, input interface{}) (
+	                         io.ReadCloser, http.Header, int64, error) {
 
 	var response *http.Response
 
-    backoff := 0
-    for i := 0; i < 8; i++ {
-        var inputReader *bytes.Reader
-        method := "POST"
+	retries := 0
+	for {
+		var inputReader io.Reader
+		isUpload := false
 
 		switch input.(type) {
 		default:
 			jsonInput, err := json.Marshal(input)
 			if err != nil {
-                return nil, 0, err
+				return nil, nil, 0, err
 			}
 			inputReader = bytes.NewReader(jsonInput)
-        case []byte:
-            inputReader = bytes.NewReader(input.([]byte))
 		case int:
-            method = "GET"
 			inputReader = bytes.NewReader([]byte(""))
+		case []byte:
+			isUpload = true
+			inputReader = bytes.NewReader(input.([]byte))
+		case *RateLimitedReader:
+			isUpload = true
+			rateLimitedReader := input.(*RateLimitedReader)
+			rateLimitedReader.Reset()
+			inputReader = rateLimitedReader
 		}
 
-        request, err := http.NewRequest(method, url, inputReader)
+
+		if isUpload {
+			if client.UploadURLs[threadIndex] == "" || client.UploadTokens[threadIndex] == "" {
+				err := client.getUploadURL(threadIndex)
 				if err != nil {
-            return nil, 0, err
+					return nil, nil, 0, err
+				}
+			}
+			requestURL = client.UploadURLs[threadIndex]
 		}
 
-        if url == B2AuthorizationURL {
-            request.Header.Set("Authorization", "Basic " + base64.StdEncoding.EncodeToString([]byte(client.AccountID + ":" + client.ApplicationKey)))
+		request, err := http.NewRequest(method, requestURL, inputReader)
+		if err != nil {
+			return nil, nil, 0, err
+		}
+
+		if requestURL == B2AuthorizationURL {
+			request.Header.Set("Authorization", "Basic "+base64.StdEncoding.EncodeToString([]byte(client.ApplicationKeyID+":"+client.ApplicationKey)))
+		} else if isUpload {
+			request.ContentLength, _ = strconv.ParseInt(requestHeaders["Content-Length"], 10, 64)
+			request.Header.Set("Authorization", client.UploadTokens[threadIndex])
 		} else {
+			client.Lock.Lock()
 			request.Header.Set("Authorization", client.AuthorizationToken)
+			client.Lock.Unlock()
+		}
+
+		if requestHeaders != nil {
+			for key, value := range requestHeaders {
+				request.Header.Set(key, value)
+			}
 		}
 
 		if client.TestMode {
 			r := rand.Float32()
-            if r < 0.5 {
+			if r < 0.5 && isUpload {
+				request.Header.Set("X-Bz-Test-Mode", "fail_some_uploads")
+			} else if r < 0.75 {
 				request.Header.Set("X-Bz-Test-Mode", "expire_some_account_authorization_tokens")
 			} else {
 				request.Header.Set("X-Bz-Test-Mode", "force_cap_exceeded")
@@ -127,58 +217,78 @@ func (client *B2Client) call(url string, input interface{}) (io.ReadCloser, int6
 
 		response, err = client.HTTPClient.Do(request)
 		if err != nil {
-            if url != B2AuthorizationURL {
-                LOG_DEBUG("BACKBLAZE_CALL", "URL request '%s' returned an error: %v", url, err)
-                backoff = client.retry(backoff, response)
-                continue
+
+			// Don't retry when the first authorization request fails
+			if requestURL == B2AuthorizationURL && !client.IsAuthorized {
+				return nil, nil, 0, err
 			}
-            return nil, 0, err
+
+			LOG_TRACE("BACKBLAZE_CALL", "[%d] URL request '%s' returned an error: %v", threadIndex, requestURL, err)
+
+			retries = client.retry(retries, response)
+			if retries <= 0 {
+				return nil, nil, 0, err
+			}
+
+			// Clear the upload url to requrest a new one on retry
+			if isUpload {
+				client.UploadURLs[threadIndex] = ""
+				client.UploadTokens[threadIndex] = ""
+			}
+			continue
+
 		}
 
 		if response.StatusCode < 300 {
-            return response.Body, response.ContentLength, nil
+			return response.Body, response.Header, response.ContentLength, nil
 		}
 
-        LOG_DEBUG("BACKBLAZE_CALL", "URL request '%s' returned status code %d", url, response.StatusCode)
+		e := &B2Error{}
+		if err := json.NewDecoder(response.Body).Decode(e); err != nil {
+			LOG_TRACE("BACKBLAZE_CALL", "[%d] URL request '%s %s' returned status code %d", threadIndex, method, requestURL, response.StatusCode)
+		} else {
+			LOG_TRACE("BACKBLAZE_CALL", "[%d] URL request '%s %s' returned %d %s", threadIndex, method, requestURL, response.StatusCode, e.Message)
+		}
 
-        io.Copy(ioutil.Discard, response.Body)
 		response.Body.Close()
+
 		if response.StatusCode == 401 {
-            if url == B2AuthorizationURL {
-                return nil, 0, fmt.Errorf("Authorization failure")
+			if requestURL == B2AuthorizationURL {
+				return nil, nil, 0, fmt.Errorf("Authorization failure")
 			}
-            client.AuthorizeAccount()
+
+			// Attempt authorization again.  If authorization is actually not done, run the random backoff
+			_, allowed := client.AuthorizeAccount(threadIndex)
+			if allowed {
 				continue
+			}
 		} else if response.StatusCode == 403 {
 			if !client.TestMode {
-                return nil, 0, fmt.Errorf("B2 cap exceeded")
+				return nil, nil, 0, fmt.Errorf("B2 cap exceeded")
 			}
 			continue
-        } else if response.StatusCode == 429  || response.StatusCode == 408 {
-            backoff = client.retry(backoff, response)
-            continue
-        } else if response.StatusCode >= 500 && response.StatusCode <= 599 {
-            backoff = client.retry(backoff, response)
-            continue
-        } else {
-            LOG_INFO("BACKBLAZE_CALL", "URL request '%s' returned status code %d", url, response.StatusCode)
-            backoff = client.retry(backoff, response)
-            continue
+		} else if response.StatusCode == 404 {
+			if http.MethodHead == method {
+				return nil, nil, 0, nil
+			}
+		} else if response.StatusCode == 416 {
+			if http.MethodHead == method {
+				// 416 Requested Range Not Satisfiable
+				return nil, nil, 0, fmt.Errorf("URL request '%s' returned %d %s", requestURL, response.StatusCode, e.Message)
+			}
 		}
 
-        defer response.Body.Close()
-
-        e := &B2Error {
+		retries = client.retry(retries, response)
+		if retries <= 0 {
+			return nil, nil, 0, fmt.Errorf("URL request '%s' returned %d %s", requestURL, response.StatusCode, e.Message)
 		}
 
-        if err := json.NewDecoder(response.Body).Decode(e); err != nil {
-            return nil, 0, err
+		if isUpload {
+			client.UploadURLs[threadIndex] = ""
+			client.UploadTokens[threadIndex] = ""
+		}
 	}
 
-        return nil, 0, e
-    }
-
-    return nil, 0, fmt.Errorf("Maximum backoff reached")
 }
 
 type B2AuthorizeAccountOutput struct {
@@ -188,11 +298,18 @@ type B2AuthorizeAccountOutput struct {
 	DownloadURL        string
 }
 
-func (client *B2Client) AuthorizeAccount() (err error) {
+func (client *B2Client) AuthorizeAccount(threadIndex int) (err error, allowed bool) {
+	client.Lock.Lock()
+	defer client.Lock.Unlock()
 
-    readCloser, _, err := client.call(B2AuthorizationURL, make(map[string]string))
+	// Don't authorize if the previous one was done less than 30 seconds ago
+	if client.LastAuthorizationTime != 0 && client.LastAuthorizationTime > time.Now().Unix() - 30 {
+		return nil, false
+	}
+
+	readCloser, _, _, err := client.call(threadIndex, B2AuthorizationURL, http.MethodPost, nil, make(map[string]string))
 	if err != nil {
-        return err
+		return err, true
 	}
 
 	defer readCloser.Close()
@@ -200,18 +317,28 @@ func (client *B2Client) AuthorizeAccount() (err error) {
 	output := &B2AuthorizeAccountOutput{}
 
 	if err = json.NewDecoder(readCloser).Decode(&output); err != nil {
-        return err
+		return err, true
 	}
 
+	// The account id may be different from the application key id so we're getting the account id from the returned
+	// json object here, which is needed by the b2_list_buckets call.
+	client.AccountID = output.AccountID
+
 	client.AuthorizationToken = output.AuthorizationToken
 	client.APIURL = output.APIURL
+	if client.DownloadURL == "" {
 		client.DownloadURL = output.DownloadURL
+	}
+	LOG_INFO("BACKBLAZE_URL", "Download URL is: %s", client.DownloadURL)
+	client.IsAuthorized = true
 
-    return nil
+	client.LastAuthorizationTime = time.Now().Unix()
+
+	return nil, true
 }
 
 type ListBucketOutput struct {
-    AccoundID string
+	AccountID  string
 	BucketID   string
 	BucketName string
 	BucketType string
@@ -221,10 +348,11 @@ func (client *B2Client) FindBucket(bucketName string) (err error) {
 
 	input := make(map[string]string)
 	input["accountId"] = client.AccountID
+	input["bucketName"] = bucketName
 
-    url := client.APIURL + "/b2api/v1/b2_list_buckets"
+	url := client.getAPIURL() + "/b2api/v1/b2_list_buckets"
 
-    readCloser, _, err := client.call(url, input)
+	readCloser, _, _, err := client.call(0, url, http.MethodPost, nil, input)
 	if err != nil {
 		return err
 	}
@@ -266,7 +394,7 @@ type B2ListFileNamesOutput struct {
 	NextFileId   string
 }
 
-func (client *B2Client) ListFileNames(startFileName string, singleFile bool, includeVersions bool) (files []*B2Entry, err error) {
+func (client *B2Client) ListFileNames(threadIndex int, startFileName string, singleFile bool, includeVersions bool) (files []*B2Entry, err error) {
 
 	maxFileCount := 1000
 	if singleFile {
@@ -284,22 +412,88 @@ func (client *B2Client) ListFileNames(startFileName string, singleFile bool, inc
 
 	input := make(map[string]interface{})
 	input["bucketId"] = client.BucketID
-    input["startFileName"] = startFileName
+	input["startFileName"] = client.StorageDir + startFileName
 	input["maxFileCount"] = maxFileCount
+	input["prefix"] = client.StorageDir
 
 	for {
-        url := client.APIURL + "/b2api/v1/b2_list_file_names"
+		apiURL := client.getAPIURL() + "/b2api/v1/b2_list_file_names"
+		requestHeaders := map[string]string{}
+		requestMethod := http.MethodPost
+		var requestInput interface{}
+		requestInput = input
 		if includeVersions {
-            url = client.APIURL + "/b2api/v1/b2_list_file_versions"
+			apiURL = client.getAPIURL() + "/b2api/v1/b2_list_file_versions"
+		} else if singleFile {
+			// handle a single file with no versions as a special case to download the last byte of the file
+			apiURL = client.getDownloadURL() + "/file/" + client.BucketName + "/" + B2Escape(client.StorageDir + startFileName)
+			// requesting byte -1 works for empty files where 0-0 fails with a 416 error
+			requestHeaders["Range"] = "bytes=-1"
+			// HEAD request
+			requestMethod = http.MethodHead
+			requestInput = 0
 		}
-        readCloser, _, err := client.call(url, input)
+		var readCloser io.ReadCloser
+		var responseHeader http.Header
+		var err error
+		readCloser, responseHeader, _, err = client.call(threadIndex, apiURL, requestMethod, requestHeaders, requestInput)
 		if err != nil {
 			return nil, err
 		}
 
+		if readCloser != nil {
 			defer readCloser.Close()
+		}
 
-        output := B2ListFileNamesOutput {
+		output := B2ListFileNamesOutput{}
+
+		if singleFile && !includeVersions {
+			if responseHeader == nil {
+				LOG_DEBUG("BACKBLAZE_LIST", "%s did not return headers", apiURL)
+				return []*B2Entry{}, nil
+			}
+			requiredHeaders := []string{
+				"x-bz-file-id",
+				"x-bz-file-name",
+			}
+			missingKeys := []string{}
+			for _, headerKey := range requiredHeaders {
+				if "" == responseHeader.Get(headerKey) {
+					missingKeys = append(missingKeys, headerKey)
+				}
+			}
+			if len(missingKeys) > 0 {
+				return nil, fmt.Errorf("%s missing headers: %s", apiURL, missingKeys)
+			}
+			// construct the B2Entry from the response headers of the download request
+			fileID := responseHeader.Get("x-bz-file-id")
+			fileName := responseHeader.Get("x-bz-file-name")
+			unescapedFileName, err := url.QueryUnescape(fileName)
+			if err == nil {
+				fileName = unescapedFileName
+			} else {
+				LOG_WARN("BACKBLAZE_UNESCAPE", "Failed to unescape the file name %s", fileName)
+			}
+			fileAction := "upload"
+			// byte range that is returned: "bytes #-#/#
+			rangeString := responseHeader.Get("Content-Range")
+			// total file size; 1 if file has content, 0 if it's empty
+			lengthString := responseHeader.Get("Content-Length")
+			var fileSize int64
+			if "" != rangeString {
+				fileSize, _ = strconv.ParseInt(rangeString[strings.Index(rangeString, "/")+1:], 0, 64)
+			} else if "" != lengthString {
+				// this should only execute if the requested file is empty and the range request didn't result in a Content-Range header
+				fileSize, _ = strconv.ParseInt(lengthString, 0, 64)
+				if fileSize != 0 {
+					return nil, fmt.Errorf("%s returned non-zero file length", apiURL)
+				}
+			} else {
+				return nil, fmt.Errorf("could not parse headers returned by %s", apiURL)
+			}
+			fileUploadTimestamp, _ := strconv.ParseInt(responseHeader.Get("X-Bz-Upload-Timestamp"), 0, 64)
+
+			return []*B2Entry{{fileID, fileName[len(client.StorageDir):], fileAction, fileSize, fileUploadTimestamp}}, nil
 		}
 
 		if err = json.NewDecoder(readCloser).Decode(&output); err != nil {
@@ -308,10 +502,8 @@ func (client *B2Client) ListFileNames(startFileName string, singleFile bool, inc
 
 		ioutil.ReadAll(readCloser)
 
-        if startFileName == "" {
-            files = append(files, output.Files...)
-        } else {
 		for _, file := range output.Files {
+			file.FileName = file.FileName[len(client.StorageDir):]
 			if singleFile {
 				if file.FileName == startFileName {
 					files = append(files, file)
@@ -333,8 +525,6 @@ func (client *B2Client) ListFileNames(startFileName string, singleFile bool, inc
 			}
 		}
 
-        }
-
 		if len(output.NextFileName) == 0 {
 			break
 		}
@@ -348,14 +538,14 @@ func (client *B2Client) ListFileNames(startFileName string, singleFile bool, inc
 	return files, nil
 }
 
-func (client *B2Client) DeleteFile(fileName string, fileID string) (err error) {
+func (client *B2Client) DeleteFile(threadIndex int, fileName string, fileID string) (err error) {
 
 	input := make(map[string]string)
-    input["fileName"] = fileName
+	input["fileName"] = client.StorageDir + fileName
 	input["fileId"] = fileID
 
-    url := client.APIURL + "/b2api/v1/b2_delete_file_version"
-    readCloser, _, err := client.call(url, input)
+	url := client.getAPIURL() + "/b2api/v1/b2_delete_file_version"
+	readCloser, _, _, err := client.call(threadIndex, url, http.MethodPost, make(map[string]string), input)
 	if err != nil {
 		return err
 	}
@@ -368,14 +558,14 @@ type B2HideFileOutput struct {
 	FileID string
 }
 
-func (client *B2Client) HideFile(fileName string) (fileID string, err error) {
+func (client *B2Client) HideFile(threadIndex int, fileName string) (fileID string, err error) {
 
 	input := make(map[string]string)
 	input["bucketId"] = client.BucketID
-    input["fileName"] = fileName
+	input["fileName"] = client.StorageDir + fileName
 
-    url := client.APIURL + "/b2api/v1/b2_hide_file"
-    readCloser, _, err := client.call(url, input)
+	url := client.getAPIURL() + "/b2api/v1/b2_hide_file"
+	readCloser, _, _, err := client.call(threadIndex, url, http.MethodPost, make(map[string]string), input)
 	if err != nil {
 		return "", err
 	}
@@ -392,11 +582,30 @@ func (client *B2Client) HideFile(fileName string) (fileID string, err error) {
 	return output.FileID, nil
 }
 
-func (client *B2Client) DownloadFile(filePath string) (io.ReadCloser, int64, error) {
+func (client *B2Client) DownloadFile(threadIndex int, filePath string) (io.ReadCloser, int64, error) {
 
-    url := client.DownloadURL + "/file/" + client.BucketName + "/" + filePath
+	if !strings.HasSuffix(filePath, ".fsl") {
+		url := client.getDownloadURL() + "/file/" + client.BucketName + "/" + B2Escape(client.StorageDir + filePath)
 
-    return client.call(url, 0)
+		readCloser, _, len, err := client.call(threadIndex, url, http.MethodGet, make(map[string]string), 0)
+		return readCloser, len, err
+	}
+
+	// We're trying to download a fossil file.  We need to find the file ID of the last 'upload' of the file.
+	filePath = strings.TrimSuffix(filePath, ".fsl")
+	entries, err := client.ListFileNames(threadIndex, filePath, true, true)
+	fileId := ""
+	for _, entry := range entries {
+		if entry.FileName == filePath && entry.Action == "upload" && entry.Size > 0 {
+			fileId = entry.FileID
+			break
+		}
+	}
+
+	// Proceed with the b2_download_file_by_id call
+	url := client.getAPIURL() + "/b2api/v1/b2_download_file_by_id?fileId=" + fileId
+	readCloser, _, len, err := client.call(threadIndex, url, http.MethodGet, make(map[string]string), 0)
+	return readCloser, len, err
 }
 
 type B2GetUploadArgumentOutput struct {
@@ -405,12 +614,12 @@ type B2GetUploadArgumentOutput struct {
 	AuthorizationToken string
 }
 
-func (client *B2Client) getUploadURL() (error) {
+func (client *B2Client) getUploadURL(threadIndex int) error {
 	input := make(map[string]string)
 	input["bucketId"] = client.BucketID
 
-    url := client.APIURL + "/b2api/v1/b2_get_upload_url"
-    readCloser, _, err := client.call(url, input)
+	url := client.getAPIURL() + "/b2api/v1/b2_get_upload_url"
+	readCloser, _, _, err := client.call(threadIndex, url, http.MethodPost, make(map[string]string), input)
 	if err != nil {
 		return err
 	}
@@ -423,98 +632,29 @@ func (client *B2Client) getUploadURL() (error) {
 		return err
 	}
 
-    client.UploadURL = output.UploadURL
-    client.UploadToken = output.AuthorizationToken
+	client.UploadURLs[threadIndex] = output.UploadURL
+	client.UploadTokens[threadIndex] = output.AuthorizationToken
 
 	return nil
 }
 
-func (client *B2Client) UploadFile(filePath string, content []byte, rateLimit int) (err error) {
-
+func (client *B2Client) UploadFile(threadIndex int, filePath string, content []byte, rateLimit int) (err error) {
 
 	hasher := sha1.New()
 	hasher.Write(content)
 	hash := hex.EncodeToString(hasher.Sum(nil))
 
 	headers := make(map[string]string)
-    headers["X-Bz-File-Name"] = filePath
+	headers["X-Bz-File-Name"] = B2Escape(client.StorageDir + filePath)
+	headers["Content-Length"] = fmt.Sprintf("%d", len(content))
 	headers["Content-Type"] = "application/octet-stream"
 	headers["X-Bz-Content-Sha1"] = hash
 
-    var response *http.Response
-
-    backoff := 0
-    for i := 0; i < 8; i++ {
-
-        if client.UploadURL == "" || client.UploadToken == "" {
-            err = client.getUploadURL()
+	readCloser, _, _, err := client.call(threadIndex, "", http.MethodPost, headers, CreateRateLimitedReader(content, rateLimit))
 	if err != nil {
 		return err
 	}
-        }
 
-        request, err := http.NewRequest("POST", client.UploadURL, CreateRateLimitedReader(content, rateLimit))
-        if err != nil {
-            return err
-        }
-        request.ContentLength = int64(len(content))
-
-        request.Header.Set("Authorization", client.UploadToken)
-        request.Header.Set("X-Bz-File-Name", filePath)
-        request.Header.Set("Content-Type", "application/octet-stream")
-        request.Header.Set("X-Bz-Content-Sha1", hash)
-
-        for key, value := range headers {
-            request.Header.Set(key, value)
-        }
-
-        if client.TestMode {
-            r := rand.Float32()
-            if r < 0.8 {
-                request.Header.Set("X-Bz-Test-Mode", "fail_some_uploads")
-            } else if r < 0.9 {
-                request.Header.Set("X-Bz-Test-Mode", "expire_some_account_authorization_tokens")
-            } else {
-                request.Header.Set("X-Bz-Test-Mode", "force_cap_exceeded")
-            }
-        }
-
-        response, err = client.HTTPClient.Do(request)
-        if err != nil {
-            LOG_DEBUG("BACKBLAZE_UPLOAD", "URL request '%s' returned an error: %v", client.UploadURL, err)
-            backoff = client.retry(backoff, response)
-            client.UploadURL = ""
-            client.UploadToken = ""
-            continue
-        }
-
-        io.Copy(ioutil.Discard, response.Body)
-        response.Body.Close()
-
-        if response.StatusCode < 300 {
+	readCloser.Close()
 	return nil
 }
-
-        LOG_DEBUG("BACKBLAZE_UPLOAD", "URL request '%s' returned status code %d", client.UploadURL, response.StatusCode)
-
-        if response.StatusCode == 401 {
-            LOG_INFO("BACKBLAZE_UPLOAD", "Re-authorizatoin required")
-            client.UploadURL = ""
-            client.UploadToken = ""
-            continue
-        } else if response.StatusCode == 403 {
-            if !client.TestMode {
-                return fmt.Errorf("B2 cap exceeded")
-            }
-            continue
-        } else {
-            LOG_INFO("BACKBLAZE_UPLOAD", "URL request '%s' returned status code %d", client.UploadURL, response.StatusCode)
-            backoff = client.retry(backoff, response)
-            client.UploadURL = ""
-            client.UploadToken = ""
-        }
-    }
-
-    return fmt.Errorf("Maximum backoff reached")
-}
-

src/duplicacy_b2client_test.go

@@ -1,133 +0,0 @@
-// Copyright (c) Acrosync LLC. All rights reserved.
-// Free for personal use and commercial trial
-// Commercial use requires per-user licenses available from https://duplicacy.com
-
-package duplicacy
-
-import (
-    "testing"
-    "crypto/sha256"
-    "encoding/hex"
-    "encoding/json"
-
-    crypto_rand "crypto/rand"
-    "math/rand"
-    "io"
-    "io/ioutil"
-)
-
-func createB2ClientForTest(t *testing.T) (*B2Client, string) {
-    config, err := ioutil.ReadFile("test_storage.conf")
-    if err != nil {
-        t.Errorf("Failed to read config file: %v", err)
-        return nil, ""
-    }
-
-    storages := make(map[string]map[string]string)
-
-    err = json.Unmarshal(config, &storages)
-    if err != nil {
-        t.Errorf("Failed to parse config file: %v", err)
-        return nil, ""
-    }
-
-    b2, found := storages["b2"]
-    if !found {
-        t.Errorf("Failed to find b2 config")
-        return nil, ""
-    }
-
-    return NewB2Client(b2["account"], b2["key"]), b2["bucket"]
-
-}
-
-func TestB2Client(t *testing.T) {
-
-    b2Client, bucket := createB2ClientForTest(t)
-    if b2Client == nil {
-        return
-    }
-
-    b2Client.TestMode = true
-
-    err := b2Client.AuthorizeAccount()
-    if err != nil {
-        t.Errorf("Failed to authorize the b2 account: %v", err)
-        return
-    }
-
-    err = b2Client.FindBucket(bucket)
-    if err != nil {
-        t.Errorf("Failed to find bucket '%s': %v", bucket, err)
-        return
-    }
-
-    testDirectory := "b2client_test/"
-
-    files, err := b2Client.ListFileNames(testDirectory, false, false)
-    if err != nil {
-        t.Errorf("Failed to list files: %v", err)
-        return
-    }
-
-    for _, file := range files {
-        err = b2Client.DeleteFile(file.FileName, file.FileID)
-        if err != nil {
-            t.Errorf("Failed to delete file '%s': %v", file.FileName, err)
-        }
-    }
-
-    maxSize := 10000
-    for i := 0; i < 20; i++ {
-        size := rand.Int() % maxSize + 1
-        content := make([]byte, size)
-        _, err := crypto_rand.Read(content)
-        if err != nil {
-            t.Errorf("Error generating random content: %v", err)
-            return
-        }
-
-        hash := sha256.Sum256(content)
-        name := hex.EncodeToString(hash[:])
-
-        err = b2Client.UploadFile(testDirectory + name, content, 100)
-        if err != nil {
-            t.Errorf("Error uploading file '%s': %v", name, err)
-            return
-        }
-    }
-
-    files, err = b2Client.ListFileNames(testDirectory, false, false)
-    if err != nil {
-        t.Errorf("Failed to list files: %v", err)
-        return
-    }
-
-    for _, file := range files {
-
-        readCloser, _, err := b2Client.DownloadFile(file.FileName)
-        if err != nil {
-            t.Errorf("Error downloading file '%s': %v", file.FileName, err)
-            return
-        }
-
-        defer readCloser.Close()
-
-        hasher := sha256.New()
-        _, err = io.Copy(hasher, readCloser)
-
-        hash := hex.EncodeToString(hasher.Sum(nil))
-
-        if testDirectory + hash != file.FileName {
-            t.Errorf("File %s has hash %s", file.FileName, hash)
-        }
-
-    }
-
-    for _, file := range files {
-        err = b2Client.DeleteFile(file.FileName, file.FileID)
-        if err != nil {
-            t.Errorf("Failed to delete file '%s': %v", file.FileName, err)
-        }
-    }
-}

src/duplicacy_b2storage.go

@@ -9,20 +9,17 @@ import (
 )
 
 type B2Storage struct {
-    RateLimitedStorage
+	StorageBase
 
-    clients []*B2Client
+	client *B2Client
 }
 
 // CreateB2Storage creates a B2 storage object.
-func CreateB2Storage(accountID string, applicationKey string, bucket string, threads int) (storage *B2Storage, err error) {
+func CreateB2Storage(accountID string, applicationKey string, downloadURL string, bucket string, storageDir string, threads int) (storage *B2Storage, err error) {
 
-    var clients []*B2Client
+	client := NewB2Client(accountID, applicationKey, downloadURL, storageDir, threads)
 
-    for i := 0; i < threads; i++ {
-        client := NewB2Client(accountID, applicationKey)
-
-        err = client.AuthorizeAccount()
+	err, _ = client.AuthorizeAccount(0)
 	if err != nil {
 		return nil, err
 	}
@@ -32,12 +29,12 @@ func CreateB2Storage(accountID string, applicationKey string, bucket string, thr
 		return nil, err
 	}
 
-        clients = append(clients, client)
+	storage = &B2Storage{
+		client: client,
 	}
 
-    storage = &B2Storage {
-        clients: clients,
-    }
+	storage.DerivedStorage = storage
+	storage.SetDefaultNestingLevels([]int{0}, 0)
 	return storage, nil
 }
 
@@ -53,7 +50,7 @@ func (storage *B2Storage) ListFiles(threadIndex int, dir string) (files []string
 		includeVersions = true
 	}
 
-    entries, err := storage.clients[threadIndex].ListFileNames(dir, false, includeVersions)
+	entries, err := storage.client.ListFileNames(threadIndex, dir, false, includeVersions)
 	if err != nil {
 		return nil, nil, err
 	}
@@ -68,7 +65,7 @@ func (storage *B2Storage) ListFiles(threadIndex int, dir string) (files []string
 			subDirs[subDir+"/"] = true
 		}
 
-        for subDir, _ := range subDirs {
+		for subDir := range subDirs {
 			files = append(files, subDir)
 		}
 	} else if dir == "chunks" {
@@ -99,7 +96,7 @@ func (storage *B2Storage) DeleteFile(threadIndex int, filePath string) (err erro
 
 	if strings.HasSuffix(filePath, ".fsl") {
 		filePath = filePath[:len(filePath)-len(".fsl")]
-        entries, err := storage.clients[threadIndex].ListFileNames(filePath, true, true)
+		entries, err := storage.client.ListFileNames(threadIndex, filePath, true, true)
 		if err != nil {
 			return err
 		}
@@ -113,7 +110,7 @@ func (storage *B2Storage) DeleteFile(threadIndex int, filePath string) (err erro
 
 			toBeDeleted = true
 
-            err = storage.clients[threadIndex].DeleteFile(filePath, entry.FileID)
+			err = storage.client.DeleteFile(threadIndex, filePath, entry.FileID)
 			if err != nil {
 				return err
 			}
@@ -122,7 +119,7 @@ func (storage *B2Storage) DeleteFile(threadIndex int, filePath string) (err erro
 		return nil
 
 	} else {
-        entries, err := storage.clients[threadIndex].ListFileNames(filePath, true, false)
+		entries, err := storage.client.ListFileNames(threadIndex, filePath, true, false)
 		if err != nil {
 			return err
 		}
@@ -130,7 +127,7 @@ func (storage *B2Storage) DeleteFile(threadIndex int, filePath string) (err erro
 		if len(entries) == 0 {
 			return nil
 		}
-        return storage.clients[threadIndex].DeleteFile(filePath, entries[0].FileID)
+		return storage.client.DeleteFile(threadIndex, filePath, entries[0].FileID)
 	}
 }
 
@@ -157,10 +154,10 @@ func (storage *B2Storage) MoveFile(threadIndex int, from string, to string) (err
 	}
 
 	if filePath == from {
-        _, err = storage.clients[threadIndex].HideFile(from)
+		_, err = storage.client.HideFile(threadIndex, from)
 		return err
 	} else {
-        entries, err := storage.clients[threadIndex].ListFileNames(filePath, true, true)
+		entries, err := storage.client.ListFileNames(threadIndex, filePath, true, true)
 		if err != nil {
 			return err
 		}
@@ -168,7 +165,7 @@ func (storage *B2Storage) MoveFile(threadIndex int, from string, to string) (err
 			return nil
 		}
 
-        return storage.clients[threadIndex].DeleteFile(filePath, entries[0].FileID)
+		return storage.client.DeleteFile(threadIndex, filePath, entries[0].FileID)
 	}
 }
 
@@ -185,7 +182,7 @@ func (storage *B2Storage) GetFileInfo(threadIndex int, filePath string) (exist b
 		filePath = filePath[:len(filePath)-len(".fsl")]
 	}
 
-    entries, err := storage.clients[threadIndex].ListFileNames(filePath, true, isFossil)
+	entries, err := storage.client.ListFileNames(threadIndex, filePath, true, isFossil)
 	if err != nil {
 		return false, false, 0, err
 	}
@@ -204,52 +201,39 @@ func (storage *B2Storage) GetFileInfo(threadIndex int, filePath string) (exist b
 	return true, false, entries[0].Size, nil
 }
 
-// FindChunk finds the chunk with the specified id.  If 'isFossil' is true, it will search for chunk files with
-// the suffix '.fsl'.
-func (storage *B2Storage) FindChunk(threadIndex int, chunkID string, isFossil bool) (filePath string, exist bool, size int64, err error) {
-    filePath = "chunks/" + chunkID
-    if isFossil {
-        filePath += ".fsl"
-    }
-    exist, _, size, err = storage.GetFileInfo(threadIndex, filePath)
-    return filePath, exist, size, err
-}
-
 // DownloadFile reads the file at 'filePath' into the chunk.
 func (storage *B2Storage) DownloadFile(threadIndex int, filePath string, chunk *Chunk) (err error) {
 
-    readCloser, _, err := storage.clients[threadIndex].DownloadFile(filePath)
+	readCloser, _, err := storage.client.DownloadFile(threadIndex, filePath)
 	if err != nil {
 		return err
 	}
 
 	defer readCloser.Close()
 
-    _, err = RateLimitedCopy(chunk, readCloser, storage.DownloadRateLimit / len(storage.clients))
+	_, err = RateLimitedCopy(chunk, readCloser, storage.DownloadRateLimit/storage.client.Threads)
 	return err
 }
 
 // UploadFile writes 'content' to the file at 'filePath'.
 func (storage *B2Storage) UploadFile(threadIndex int, filePath string, content []byte) (err error) {
-    return storage.clients[threadIndex].UploadFile(filePath, content, storage.UploadRateLimit / len(storage.clients))
+	return storage.client.UploadFile(threadIndex, filePath, content, storage.UploadRateLimit/storage.client.Threads)
 }
 
 // If a local snapshot cache is needed for the storage to avoid downloading/uploading chunks too often when
 // managing snapshots.
-func (storage *B2Storage) IsCacheNeeded() (bool) { return true }
+func (storage *B2Storage) IsCacheNeeded() bool { return true }
 
 // If the 'MoveFile' method is implemented.
-func (storage *B2Storage) IsMoveFileImplemented() (bool) { return true }
+func (storage *B2Storage) IsMoveFileImplemented() bool { return true }
 
 // If the storage can guarantee strong consistency.
-func (storage *B2Storage) IsStrongConsistent() (bool) { return true }
+func (storage *B2Storage) IsStrongConsistent() bool { return true }
 
 // If the storage supports fast listing of files names.
-func (storage *B2Storage) IsFastListing() (bool) { return true }
+func (storage *B2Storage) IsFastListing() bool { return true }
 
 // Enable the test mode.
 func (storage *B2Storage) EnableTestMode() {
-    for _, client := range storage.clients {
-        client.TestMode = true
-    }
+	storage.client.TestMode = true
 }

src/duplicacy_backupmanager_test.go

@@ -5,15 +5,15 @@
 package duplicacy
 
 import (
-    "os"
+	crypto_rand "crypto/rand"
+	"crypto/sha256"
+	"encoding/hex"
 	"io"
+	"math/rand"
+	"os"
 	"path"
 	"testing"
-    "math/rand"
-    "encoding/hex"
 	"time"
-    "crypto/sha256"
-    crypto_rand "crypto/rand"
 
 	"runtime/debug"
 )
@@ -104,6 +104,27 @@ func modifyFile(path string, portion float32) {
 	}
 }
 
+func checkExistence(t *testing.T, path string, exists bool, isDir bool) {
+	stat, err := os.Stat(path)
+	if exists {
+		if err != nil {
+			t.Errorf("%s does not exist: %v", path, err)
+		} else if isDir {
+			if !stat.Mode().IsDir() {
+				t.Errorf("%s is not a directory", path)
+			}
+		} else {
+			if stat.Mode().IsDir() {
+				t.Errorf("%s is not a file", path)
+			}
+		}
+	} else {
+		if err == nil || !os.IsNotExist(err) {
+			t.Errorf("%s may exist: %v", path, err)
+		}
+	}
+}
+
 func truncateFile(path string) {
 	file, err := os.OpenFile(path, os.O_WRONLY, 0644)
 	if err != nil {
@@ -148,6 +169,12 @@ func getFileHash(path string) (hash string) {
 	return hex.EncodeToString(hasher.Sum(nil))
 }
 
+func assertRestoreFailures(t *testing.T, failedFiles int, expectedFailedFiles int) {
+	if failedFiles != expectedFailedFiles {
+		t.Errorf("Failed to restore %d instead of %d file(s)", failedFiles, expectedFailedFiles)
+	}
+}
+
 func TestBackupManager(t *testing.T) {
 
 	rand.Seed(time.Now().UnixNano())
@@ -173,6 +200,9 @@ func TestBackupManager(t *testing.T) {
 
 	os.Mkdir(testDir+"/repository1", 0700)
 	os.Mkdir(testDir+"/repository1/dir1", 0700)
+	os.Mkdir(testDir+"/repository1/.duplicacy", 0700)
+	os.Mkdir(testDir+"/repository2", 0700)
+	os.Mkdir(testDir+"/repository2/.duplicacy", 0700)
 
 	maxFileSize := 1000000
 	//maxFileSize := 200000
@@ -202,29 +232,37 @@ func TestBackupManager(t *testing.T) {
 	cleanStorage(storage)
 
 	time.Sleep(time.Duration(delay) * time.Second)
-    if testFixedChunkSize {
-        if !ConfigStorage(storage, 100, 64 * 1024, 64 * 1024, 64 * 1024, password, nil) {
+
+	dataShards := 0
+	parityShards := 0
+	if *testErasureCoding {
+		dataShards = 5
+		parityShards = 2
+	}
+
+	if *testFixedChunkSize {
+		if !ConfigStorage(storage, 16384, 100, 64*1024, 64*1024, 64*1024, password, nil, false, "", dataShards, parityShards) {
 			t.Errorf("Failed to initialize the storage")
 		}
 	} else {
-        if !ConfigStorage(storage, 100, 64 * 1024, 256 * 1024, 16 * 1024, password, nil) {
+		if !ConfigStorage(storage, 16384, 100, 64*1024, 256*1024, 16*1024, password, nil, false, "", dataShards, parityShards) {
 			t.Errorf("Failed to initialize the storage")
 		}
 	}
 
-
 	time.Sleep(time.Duration(delay) * time.Second)
 
-    SetDuplicacyPreferencePath(testDir + "/repository1")
-    backupManager := CreateBackupManager("host1", storage, testDir, password)
+	SetDuplicacyPreferencePath(testDir + "/repository1/.duplicacy")
+	backupManager := CreateBackupManager("host1", storage, testDir, password, "", "", false)
 	backupManager.SetupSnapshotCache("default")
 
-    SetDuplicacyPreferencePath(testDir + "/repository1")
-    backupManager.Backup(testDir + "/repository1", /*quickMode=*/true, threads, "first", false, false)
+	SetDuplicacyPreferencePath(testDir + "/repository1/.duplicacy")
+	backupManager.Backup(testDir+"/repository1" /*quickMode=*/, true, threads, "first", false, false, 0, false, 1024, 1024)
 	time.Sleep(time.Duration(delay) * time.Second)
-    SetDuplicacyPreferencePath(testDir + "/repository2")
-    backupManager.Restore(testDir + "/repository2", threads, /*inPlace=*/false, /*quickMode=*/false, threads, /*overwrite=*/true,
-                          /*deleteMode=*/false, /*showStatistics=*/false, /*patterns=*/nil)
+	SetDuplicacyPreferencePath(testDir + "/repository2/.duplicacy")
+	failedFiles := backupManager.Restore(testDir+"/repository2", threads /*inPlace=*/, false /*quickMode=*/, false, threads /*overwrite=*/, true,
+		/*deleteMode=*/ false /*setowner=*/, false /*showStatistics=*/, false /*patterns=*/, nil /*allowFailures=*/, false)
+	assertRestoreFailures(t, failedFiles, 0)
 
 	for _, f := range []string{"file1", "file2", "dir1/file3"} {
 		if _, err := os.Stat(testDir + "/repository2/" + f); os.IsNotExist(err) {
@@ -243,12 +281,13 @@ func TestBackupManager(t *testing.T) {
 	modifyFile(testDir+"/repository1/file2", 0.2)
 	modifyFile(testDir+"/repository1/dir1/file3", 0.3)
 
-    SetDuplicacyPreferencePath(testDir + "/repository1")
-    backupManager.Backup(testDir + "/repository1", /*quickMode=*/true, threads, "second", false, false)
+	SetDuplicacyPreferencePath(testDir + "/repository1/.duplicacy")
+	backupManager.Backup(testDir+"/repository1" /*quickMode=*/, true, threads, "second", false, false, 0, false, 1024, 1024)
 	time.Sleep(time.Duration(delay) * time.Second)
-    SetDuplicacyPreferencePath(testDir + "/repository2")
-    backupManager.Restore(testDir + "/repository2", 2, /*inPlace=*/true, /*quickMode=*/true, threads, /*overwrite=*/true,
-                          /*deleteMode=*/false, /*showStatistics=*/false, /*patterns=*/nil)
+	SetDuplicacyPreferencePath(testDir + "/repository2/.duplicacy")
+	failedFiles = backupManager.Restore(testDir+"/repository2", 2 /*inPlace=*/, true /*quickMode=*/, true, threads /*overwrite=*/, true,
+		/*deleteMode=*/ false /*setowner=*/, false /*showStatistics=*/, false /*patterns=*/, nil /*allowFailures=*/, false)
+	assertRestoreFailures(t, failedFiles, 0)
 
 	for _, f := range []string{"file1", "file2", "dir1/file3"} {
 		hash1 := getFileHash(testDir + "/repository1/" + f)
@@ -258,13 +297,26 @@ func TestBackupManager(t *testing.T) {
 		}
 	}
 
+	// Truncate file2 and add a few empty directories
 	truncateFile(testDir + "/repository1/file2")
-    SetDuplicacyPreferencePath(testDir + "/repository1")
-    backupManager.Backup(testDir + "/repository1", /*quickMode=*/false, threads, "third", false, false)
+	os.Mkdir(testDir+"/repository1/dir2", 0700)
+	os.Mkdir(testDir+"/repository1/dir2/dir3", 0700)
+	os.Mkdir(testDir+"/repository1/dir4", 0700)
+	SetDuplicacyPreferencePath(testDir + "/repository1/.duplicacy")
+	backupManager.Backup(testDir+"/repository1" /*quickMode=*/, false, threads, "third", false, false, 0, false, 1024, 1024)
 	time.Sleep(time.Duration(delay) * time.Second)
-    SetDuplicacyPreferencePath(testDir + "/repository2")
-    backupManager.Restore(testDir + "/repository2", 3, /*inPlace=*/true, /*quickMode=*/false, threads, /*overwrite=*/true,
-                          /*deleteMode=*/false, /*showStatistics=*/false, /*patterns=*/nil)
+
+	// Create some directories and files under repository2 that will be deleted during restore
+	os.Mkdir(testDir+"/repository2/dir5", 0700)
+	os.Mkdir(testDir+"/repository2/dir5/dir6", 0700)
+	os.Mkdir(testDir+"/repository2/dir7", 0700)
+	createRandomFile(testDir+"/repository2/file4", 100)
+	createRandomFile(testDir+"/repository2/dir5/file5", 100)
+
+	SetDuplicacyPreferencePath(testDir + "/repository2/.duplicacy")
+	failedFiles = backupManager.Restore(testDir+"/repository2", 3 /*inPlace=*/, true /*quickMode=*/, false, threads /*overwrite=*/, true,
+		/*deleteMode=*/ true /*setowner=*/, false /*showStatistics=*/, false /*patterns=*/, nil /*allowFailures=*/, false)
+	assertRestoreFailures(t, failedFiles, 0)
 
 	for _, f := range []string{"file1", "file2", "dir1/file3"} {
 		hash1 := getFileHash(testDir + "/repository1/" + f)
@@ -274,11 +326,25 @@ func TestBackupManager(t *testing.T) {
 		}
 	}
 
+	// These files/dirs should not exist because deleteMode == true
+	checkExistence(t, testDir+"/repository2/dir5", false, false)
+	checkExistence(t, testDir+"/repository2/dir5/dir6", false, false)
+	checkExistence(t, testDir+"/repository2/dir7", false, false)
+	checkExistence(t, testDir+"/repository2/file4", false, false)
+	checkExistence(t, testDir+"/repository2/dir5/file5", false, false)
+
+	// These empty dirs should exist
+	checkExistence(t, testDir+"/repository2/dir2", true, true)
+	checkExistence(t, testDir+"/repository2/dir2/dir3", true, true)
+	checkExistence(t, testDir+"/repository2/dir4", true, true)
+
 	// Remove file2 and dir1/file3 and restore them from revision 3
 	os.Remove(testDir + "/repository1/file2")
 	os.Remove(testDir + "/repository1/dir1/file3")
-    backupManager.Restore(testDir + "/repository1", 3, /*inPlace=*/true, /*quickMode=*/false, threads, /*overwrite=*/true,
-                          /*deleteMode=*/false, /*showStatistics=*/false, /*patterns=*/[]string{"+file2", "+dir1/file3", "-*"})
+	SetDuplicacyPreferencePath(testDir + "/repository1/.duplicacy")
+	failedFiles = backupManager.Restore(testDir+"/repository1", 3 /*inPlace=*/, true /*quickMode=*/, false, threads /*overwrite=*/, true,
+		/*deleteMode=*/ false /*setowner=*/, false /*showStatistics=*/, false /*patterns=*/, []string{"+file2", "+dir1/file3", "-*"} /*allowFailures=*/, false)
+	assertRestoreFailures(t, failedFiles, 0)
 
 	for _, f := range []string{"file1", "file2", "dir1/file3"} {
 		hash1 := getFileHash(testDir + "/repository1/" + f)
@@ -288,7 +354,381 @@ func TestBackupManager(t *testing.T) {
 		}
 	}
 
+	numberOfSnapshots := backupManager.SnapshotManager.ListSnapshots( /*snapshotID*/ "host1" /*revisionsToList*/, nil /*tag*/, "" /*showFiles*/, false /*showChunks*/, false)
+	if numberOfSnapshots != 3 {
+		t.Errorf("Expected 3 snapshots but got %d", numberOfSnapshots)
+	}
+			
+	backupManager.SnapshotManager.CheckSnapshots( /*snapshotID*/ "host1", /*revisions*/ []int{1, 2, 3}, /*tag*/ "", /*showStatistics*/ false,
+	    /*showTabular*/ false, /*checkFiles*/ false, /*checkChunks*/ false, /*searchFossils*/ false, /*resurrect*/ false, /*rewiret*/ false, 1,  /*allowFailures*/false)
+	backupManager.SnapshotManager.PruneSnapshots("host1", "host1" /*revisions*/, []int{1} /*tags*/, nil /*retentions*/, nil,
+		/*exhaustive*/ false /*exclusive=*/, false /*ignoredIDs*/, nil /*dryRun*/, false /*deleteOnly*/, false /*collectOnly*/, false, 1)
+	numberOfSnapshots = backupManager.SnapshotManager.ListSnapshots( /*snapshotID*/ "host1" /*revisionsToList*/, nil /*tag*/, "" /*showFiles*/, false /*showChunks*/, false)
+	if numberOfSnapshots != 2 {
+		t.Errorf("Expected 2 snapshots but got %d", numberOfSnapshots)
+	}
+	backupManager.SnapshotManager.CheckSnapshots( /*snapshotID*/ "host1", /*revisions*/ []int{2, 3}, /*tag*/ "", /*showStatistics*/ false,
+	     /*showTabular*/ false, /*checkFiles*/ false, /*checkChunks*/ false, /*searchFossils*/ false, /*resurrect*/ false, /*rewiret*/ false, 1, /*allowFailures*/ false)
+	backupManager.Backup(testDir+"/repository1" /*quickMode=*/, false, threads, "fourth", false, false, 0, false, 1024, 1024)
+	backupManager.SnapshotManager.PruneSnapshots("host1", "host1" /*revisions*/, nil /*tags*/, nil /*retentions*/, nil,
+		/*exhaustive*/ false /*exclusive=*/, true /*ignoredIDs*/, nil /*dryRun*/, false /*deleteOnly*/, false /*collectOnly*/, false, 1)
+	numberOfSnapshots = backupManager.SnapshotManager.ListSnapshots( /*snapshotID*/ "host1" /*revisionsToList*/, nil /*tag*/, "" /*showFiles*/, false /*showChunks*/, false)
+	if numberOfSnapshots != 3 {
+		t.Errorf("Expected 3 snapshots but got %d", numberOfSnapshots)
+	}
+	backupManager.SnapshotManager.CheckSnapshots( /*snapshotID*/ "host1", /*revisions*/ []int{2, 3, 4}, /*tag*/ "", /*showStatistics*/ false,
+	    /*showTabular*/ false, /*checkFiles*/ false, /*checkChunks*/ false, /*searchFossils*/ false, /*resurrect*/ false, /*rewiret*/ false, 1, /*allowFailures*/ false)
+
 	/*buf := make([]byte, 1<<16)
 	  runtime.Stack(buf, true)
 	  fmt.Printf("%s", buf)*/
 }
+
+// Create file with random file with certain seed
+func createRandomFileSeeded(path string, maxSize int, seed int64) {
+	rand.Seed(seed)
+	file, err := os.OpenFile(path, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0644)
+	if err != nil {
+		LOG_ERROR("RANDOM_FILE", "Can't open %s for writing: %v", path, err)
+		return
+	}
+
+	defer file.Close()
+
+	size := maxSize/2 + rand.Int()%(maxSize/2)
+
+	buffer := make([]byte, 32*1024)
+	for size > 0 {
+		bytes := size
+		if bytes > cap(buffer) {
+			bytes = cap(buffer)
+		}
+		rand.Read(buffer[:bytes])
+		bytes, err = file.Write(buffer[:bytes])
+		if err != nil {
+			LOG_ERROR("RANDOM_FILE", "Failed to write to %s: %v", path, err)
+			return
+		}
+		size -= bytes
+	}
+}
+
+func corruptFile(path string, start int, length int, seed int64) {
+	rand.Seed(seed)
+
+	file, err := os.OpenFile(path, os.O_WRONLY, 0644)
+	if err != nil {
+		LOG_ERROR("CORRUPT_FILE", "Can't open %s for writing: %v", path, err)
+		return
+	}
+
+	defer func() {
+		if file != nil {
+			file.Close()
+		}
+	}()
+
+	_, err = file.Seek(int64(start), 0)
+	if err != nil {
+		LOG_ERROR("CORRUPT_FILE", "Can't seek to the offset %d: %v", start, err)
+		return
+	}
+
+	buffer := make([]byte, length)
+	rand.Read(buffer)
+
+	_, err = file.Write(buffer)
+	if err != nil {
+		LOG_ERROR("CORRUPT_FILE", "Failed to write to %s: %v", path, err)
+		return
+	}
+}
+
+func TestPersistRestore(t *testing.T) {
+	// We want deterministic output here so we can test the expected files are corrupted by missing or corrupt chunks
+	// There use rand functions with fixed seed, and known keys
+
+	setTestingT(t)
+	SetLoggingLevel(INFO)
+
+	defer func() {
+		if r := recover(); r != nil {
+			switch e := r.(type) {
+			case Exception:
+				t.Errorf("%s %s", e.LogID, e.Message)
+				debug.PrintStack()
+			default:
+				t.Errorf("%v", e)
+				debug.PrintStack()
+			}
+		}
+	}()
+
+	testDir := path.Join(os.TempDir(), "duplicacy_test")
+	os.RemoveAll(testDir)
+	os.MkdirAll(testDir, 0700)
+	os.Mkdir(testDir+"/repository1", 0700)
+	os.Mkdir(testDir+"/repository1/dir1", 0700)
+	os.Mkdir(testDir+"/repository1/.duplicacy", 0700)
+	os.Mkdir(testDir+"/repository2", 0700)
+	os.Mkdir(testDir+"/repository2/.duplicacy", 0700)
+	os.Mkdir(testDir+"/repository3", 0700)
+	os.Mkdir(testDir+"/repository3/.duplicacy", 0700)
+
+	maxFileSize := 1000000
+	//maxFileSize := 200000
+
+	createRandomFileSeeded(testDir+"/repository1/file1", maxFileSize,1)
+	createRandomFileSeeded(testDir+"/repository1/file2", maxFileSize,2)
+	createRandomFileSeeded(testDir+"/repository1/dir1/file3", maxFileSize,3)
+
+	threads := 1
+
+	password := "duplicacy"
+
+	// We want deterministic output, plus ability to test encrypted storage
+	// So make unencrypted storage with default keys, and encrypted as bit-identical copy of this but with password
+	unencStorage, err := loadStorage(testDir+"/unenc_storage", threads)
+	if err != nil {
+		t.Errorf("Failed to create storage: %v", err)
+		return
+	}
+	delay := 0
+	if _, ok := unencStorage.(*ACDStorage); ok {
+		delay = 1
+	}
+	if _, ok := unencStorage.(*OneDriveStorage); ok {
+		delay = 5
+	}
+
+	time.Sleep(time.Duration(delay) * time.Second)
+	cleanStorage(unencStorage)
+
+	if !ConfigStorage(unencStorage, 16384, 100, 64*1024, 256*1024, 16*1024, "", nil, false, "", 0, 0) {
+		t.Errorf("Failed to initialize the unencrypted storage")
+	}
+	time.Sleep(time.Duration(delay) * time.Second)
+	unencConfig, _, err := DownloadConfig(unencStorage, "")
+	if err != nil {
+		t.Errorf("Failed to download storage config: %v", err)
+		return
+	}
+
+	// Make encrypted storage
+	storage, err := loadStorage(testDir+"/enc_storage", threads)
+	if err != nil {
+		t.Errorf("Failed to create encrypted storage: %v", err)
+		return
+	}
+	time.Sleep(time.Duration(delay) * time.Second)
+	cleanStorage(storage)
+
+	if !ConfigStorage(storage, 16384, 100, 64*1024, 256*1024, 16*1024, password, unencConfig, true, "", 0, 0) {
+		t.Errorf("Failed to initialize the encrypted storage")
+	}
+	time.Sleep(time.Duration(delay) * time.Second)
+
+	// do unencrypted backup
+	SetDuplicacyPreferencePath(testDir + "/repository1/.duplicacy")
+	unencBackupManager := CreateBackupManager("host1", unencStorage, testDir, "", "", "", false)
+	unencBackupManager.SetupSnapshotCache("default")
+
+	SetDuplicacyPreferencePath(testDir + "/repository1/.duplicacy")
+	unencBackupManager.Backup(testDir+"/repository1" /*quickMode=*/, true, threads, "first", false, false, 0, false, 1024, 1024)
+	time.Sleep(time.Duration(delay) * time.Second)
+
+
+	// do encrypted backup
+	SetDuplicacyPreferencePath(testDir + "/repository1/.duplicacy")
+	encBackupManager := CreateBackupManager("host1", storage, testDir, password, "", "", false)
+	encBackupManager.SetupSnapshotCache("default")
+
+	SetDuplicacyPreferencePath(testDir + "/repository1/.duplicacy")
+	encBackupManager.Backup(testDir+"/repository1" /*quickMode=*/, true, threads, "first", false, false, 0, false, 1024, 1024)
+	time.Sleep(time.Duration(delay) * time.Second)
+
+
+	// check snapshots
+	unencBackupManager.SnapshotManager.CheckSnapshots( /*snapshotID*/ "host1", /*revisions*/ []int{1}, /*tag*/ "",
+		/*showStatistics*/ true, /*showTabular*/ false, /*checkFiles*/ true, /*checkChunks*/ false,
+		/*searchFossils*/ false, /*resurrect*/ false, /*rewiret*/ false, 1, /*allowFailures*/ false)
+
+	encBackupManager.SnapshotManager.CheckSnapshots( /*snapshotID*/ "host1", /*revisions*/ []int{1}, /*tag*/ "",
+		/*showStatistics*/ true, /*showTabular*/ false, /*checkFiles*/ true, /*checkChunks*/ false,
+		 /*searchFossils*/ false, /*resurrect*/ false, /*rewiret*/ false, 1, /*allowFailures*/ false)
+		
+	// check functions
+	checkAllUncorrupted := func(cmpRepository string) {
+			for _, f := range []string{"file1", "file2", "dir1/file3"} {
+				if _, err := os.Stat(testDir + cmpRepository + "/" + f); os.IsNotExist(err) {
+					t.Errorf("File %s does not exist", f)
+					continue
+				}
+
+				hash1 := getFileHash(testDir + "/repository1/" + f)
+				hash2 := getFileHash(testDir + cmpRepository + "/" + f)
+				if hash1 != hash2 {
+					t.Errorf("File %s has different hashes: %s vs %s", f, hash1, hash2)
+				}
+		}
+	}
+	checkMissingFile := func(cmpRepository string, expectMissing string) {
+			for _, f := range []string{"file1", "file2", "dir1/file3"} {
+				_, err := os.Stat(testDir + cmpRepository + "/" + f)
+				if err==nil {
+					if f==expectMissing {
+						t.Errorf("File %s exists, expected to be missing", f)
+					}
+					continue
+				}
+				if os.IsNotExist(err) {
+					if f!=expectMissing {
+						t.Errorf("File %s does not exist", f)
+					}
+					continue
+				}
+
+				hash1 := getFileHash(testDir + "/repository1/" + f)
+				hash2 := getFileHash(testDir + cmpRepository + "/" + f)
+				if hash1 != hash2 {
+					t.Errorf("File %s has different hashes: %s vs %s", f, hash1, hash2)
+				}
+		}
+	}
+	checkCorruptedFile  := func(cmpRepository string, expectCorrupted string) {
+		for _, f := range []string{"file1", "file2", "dir1/file3"} {
+			if _, err := os.Stat(testDir + cmpRepository + "/" + f); os.IsNotExist(err) {
+				t.Errorf("File %s does not exist", f)
+				continue
+			}
+	
+			hash1 := getFileHash(testDir + "/repository1/" + f)
+			hash2 := getFileHash(testDir + cmpRepository + "/" + f)
+			if (f==expectCorrupted) {
+				if hash1 == hash2 {
+					t.Errorf("File %s has same hashes, expected to be corrupted: %s vs %s", f, hash1, hash2)
+				}
+	
+			} else {
+				if hash1 != hash2 {
+					t.Errorf("File %s has different hashes: %s vs %s", f, hash1, hash2)
+				}
+			}
+		}
+	}
+
+	// test restore all uncorrupted to repository3
+	SetDuplicacyPreferencePath(testDir + "/repository3/.duplicacy")
+	failedFiles := unencBackupManager.Restore(testDir+"/repository3", threads /*inPlace=*/, true /*quickMode=*/, false, threads /*overwrite=*/, false,
+		 /*deleteMode=*/ false /*setowner=*/, false /*showStatistics=*/, false /*patterns=*/, nil /*allowFailures=*/, false)
+	assertRestoreFailures(t, failedFiles, 0)
+	checkAllUncorrupted("/repository3")
+
+	// test for corrupt files and -persist
+	// corrupt a chunk 
+	chunkToCorrupt1 := "/4d/538e5dfd2b08e782bfeb56d1360fb5d7eb9d8c4b2531cc2fca79efbaec910c"
+		// this should affect file1
+	chunkToCorrupt2 := "/2b/f953a766d0196ce026ae259e76e3c186a0e4bcd3ce10f1571d17f86f0a5497"
+		// this should affect dir1/file3
+	
+	for i := 0; i < 2; i++ {
+		if i==0 {
+			// test corrupt chunks
+			corruptFile(testDir+"/unenc_storage"+"/chunks"+chunkToCorrupt1, 128, 128, 4)
+			corruptFile(testDir+"/enc_storage"+"/chunks"+chunkToCorrupt2, 128, 128, 4)
+		} else {
+			// test missing chunks
+			os.Remove(testDir+"/unenc_storage"+"/chunks"+chunkToCorrupt1)
+			os.Remove(testDir+"/enc_storage"+"/chunks"+chunkToCorrupt2)
+		}
+
+		// This is to make sure that allowFailures is set to true.  Note that this is not needed
+		// in the production code because chunkOperator can be only recreated multiple time in tests.
+		if unencBackupManager.SnapshotManager.chunkOperator != nil {
+			unencBackupManager.SnapshotManager.chunkOperator.allowFailures = true
+		}
+
+		if encBackupManager.SnapshotManager.chunkOperator != nil {
+			encBackupManager.SnapshotManager.chunkOperator.allowFailures = true
+		}
+
+		// check snapshots with --persist (allowFailures == true)
+		// this would cause a panic and os.Exit from duplicacy_log if allowFailures == false
+		unencBackupManager.SnapshotManager.CheckSnapshots( /*snapshotID*/ "host1", /*revisions*/ []int{1}, /*tag*/ "",
+			/*showStatistics*/ true, /*showTabular*/ false, /*checkFiles*/ true, /*checkChunks*/ false,
+			/*searchFossils*/ false, /*resurrect*/ false, /*rewrite*/ false, 1, /*allowFailures*/ true)
+
+		encBackupManager.SnapshotManager.CheckSnapshots( /*snapshotID*/ "host1", /*revisions*/ []int{1}, /*tag*/ "",
+			/*showStatistics*/ true, /*showTabular*/ false, /*checkFiles*/ true, /*checkChunks*/ false,
+			/*searchFossils*/ false, /*resurrect*/ false, /*rewrite*/ false, 1, /*allowFailures*/ true)
+
+	
+		// test restore corrupted, inPlace = true, corrupted files will have hash failures
+		os.RemoveAll(testDir+"/repository2")
+		SetDuplicacyPreferencePath(testDir + "/repository2/.duplicacy")
+		failedFiles = unencBackupManager.Restore(testDir+"/repository2", threads /*inPlace=*/, true /*quickMode=*/, false, threads /*overwrite=*/, false,
+			/*deleteMode=*/ false /*setowner=*/, false /*showStatistics=*/, false /*patterns=*/, nil /*allowFailures=*/, true)
+		assertRestoreFailures(t, failedFiles, 1)
+
+		// check restore, expect file1 to be corrupted
+		checkCorruptedFile("/repository2", "file1")
+
+		
+		os.RemoveAll(testDir+"/repository2")
+		SetDuplicacyPreferencePath(testDir + "/repository2/.duplicacy")
+		failedFiles = encBackupManager.Restore(testDir+"/repository2", threads /*inPlace=*/, true /*quickMode=*/, false, threads /*overwrite=*/, false,
+			/*deleteMode=*/ false /*setowner=*/, false /*showStatistics=*/, false /*patterns=*/, nil /*allowFailures=*/, true)
+		assertRestoreFailures(t, failedFiles, 1)
+
+		// check restore, expect file3 to be corrupted
+		checkCorruptedFile("/repository2", "dir1/file3")
+
+		//SetLoggingLevel(DEBUG)
+		// test restore corrupted, inPlace = false, corrupted files will be missing
+		os.RemoveAll(testDir+"/repository2")
+		SetDuplicacyPreferencePath(testDir + "/repository2/.duplicacy")
+		failedFiles = unencBackupManager.Restore(testDir+"/repository2", threads /*inPlace=*/, false /*quickMode=*/, false, threads /*overwrite=*/, false,
+			/*deleteMode=*/ false /*setowner=*/, false /*showStatistics=*/, false /*patterns=*/, nil /*allowFailures=*/, true)
+		assertRestoreFailures(t, failedFiles, 1)
+
+		// check restore, expect file1 to be corrupted
+		checkMissingFile("/repository2", "file1")
+
+		
+		os.RemoveAll(testDir+"/repository2")
+		SetDuplicacyPreferencePath(testDir + "/repository2/.duplicacy")
+		failedFiles = encBackupManager.Restore(testDir+"/repository2", threads /*inPlace=*/, false /*quickMode=*/, false, threads /*overwrite=*/, false,
+			/*deleteMode=*/ false /*setowner=*/, false /*showStatistics=*/, false /*patterns=*/, nil /*allowFailures=*/, true)
+		assertRestoreFailures(t, failedFiles, 1)
+
+		// check restore, expect file3 to be corrupted
+		checkMissingFile("/repository2", "dir1/file3")
+
+		// test restore corrupted files from different backups, inPlace = true
+		// with overwrite=true, corrupted file1 from unenc will be restored correctly from enc
+		// the latter will not touch the existing file3 with correct hash
+		os.RemoveAll(testDir+"/repository2")
+		failedFiles = unencBackupManager.Restore(testDir+"/repository2", threads /*inPlace=*/, true /*quickMode=*/, false, threads /*overwrite=*/, false,
+			/*deleteMode=*/ false /*setowner=*/, false /*showStatistics=*/, false /*patterns=*/, nil /*allowFailures=*/, true)
+		assertRestoreFailures(t, failedFiles, 1)
+
+		failedFiles = encBackupManager.Restore(testDir+"/repository2", threads /*inPlace=*/, true /*quickMode=*/, false, threads /*overwrite=*/, true,
+			/*deleteMode=*/ false /*setowner=*/, false /*showStatistics=*/, false /*patterns=*/, nil /*allowFailures=*/, true)
+		assertRestoreFailures(t, failedFiles, 0)
+		checkAllUncorrupted("/repository2")
+
+		// restore to repository3, with overwrite and allowFailures (true/false), quickMode = false (use hashes)
+		// should always succeed as uncorrupted files already exist with correct hash, so these will be ignored
+		SetDuplicacyPreferencePath(testDir + "/repository3/.duplicacy")
+		failedFiles = unencBackupManager.Restore(testDir+"/repository3", threads /*inPlace=*/, true /*quickMode=*/, false, threads /*overwrite=*/, true,
+			/*deleteMode=*/ false /*setowner=*/, false /*showStatistics=*/, false /*patterns=*/, nil /*allowFailures=*/, false)
+		assertRestoreFailures(t, failedFiles, 0)
+		checkAllUncorrupted("/repository3")
+
+		failedFiles = unencBackupManager.Restore(testDir+"/repository3", threads /*inPlace=*/, true /*quickMode=*/, false, threads /*overwrite=*/, true,
+			/*deleteMode=*/ false /*setowner=*/, false /*showStatistics=*/, false /*patterns=*/, nil /*allowFailures=*/, true)
+		assertRestoreFailures(t, failedFiles, 0)
+		checkAllUncorrupted("/repository3")
+	}
+
+}

src/duplicacy_benchmark.go

@@ -0,0 +1,235 @@
+// Copyright (c) Acrosync LLC. All rights reserved.
+// Free for personal use and commercial trial
+// Commercial use requires per-user licenses available from https://duplicacy.com
+
+package duplicacy
+
+import (
+	"bytes"
+	"crypto/sha256"
+	"encoding/hex"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"math/rand"
+	"os"
+	"path/filepath"
+	"time"
+)
+
+func benchmarkSplit(reader *bytes.Reader, fileSize int64, chunkSize int, compression bool, encryption bool, annotation string) {
+
+	config := CreateConfig()
+	config.CompressionLevel = DEFAULT_COMPRESSION_LEVEL
+	config.AverageChunkSize = chunkSize
+	config.MaximumChunkSize = chunkSize * 4
+	config.MinimumChunkSize = chunkSize / 4
+	config.ChunkSeed = []byte("duplicacy")
+
+	config.HashKey = DEFAULT_KEY
+	config.IDKey = DEFAULT_KEY
+
+	maker := CreateFileChunkMaker(config, false)
+
+	startTime := float64(time.Now().UnixNano()) / 1e9
+	numberOfChunks := 0
+	reader.Seek(0, os.SEEK_SET)
+
+	chunkFunc := func(chunk *Chunk) {
+		if compression {
+			key := ""
+			if encryption {
+				key = "0123456789abcdef0123456789abcdef"
+			}
+			err := chunk.Encrypt([]byte(key), "", false)
+			if err != nil {
+				LOG_ERROR("BENCHMARK_ENCRYPT", "Failed to encrypt the chunk: %v", err)
+			}
+		}
+		config.PutChunk(chunk)
+		numberOfChunks++
+	}
+
+	maker.AddData(reader, chunkFunc)
+	maker.AddData(nil, chunkFunc)
+
+	runningTime := float64(time.Now().UnixNano())/1e9 - startTime
+	speed := int64(float64(fileSize) / runningTime)
+	LOG_INFO("BENCHMARK_SPLIT", "Split %s bytes into %d chunks %s in %.2fs: %s/s", PrettySize(fileSize), numberOfChunks, annotation,
+		runningTime, PrettySize(speed))
+
+	return
+}
+
+func benchmarkRun(threads int, chunkCount int, job func(threadIndex int, chunkIndex int)) {
+	indexChannel := make(chan int, chunkCount)
+	stopChannel := make(chan int, threads)
+	finishChannel := make(chan int, threads)
+
+	// Start the uploading goroutines
+	for i := 0; i < threads; i++ {
+		go func(threadIndex int) {
+			defer CatchLogException()
+			for {
+				select {
+				case chunkIndex := <-indexChannel:
+					job(threadIndex, chunkIndex)
+					finishChannel <- 0
+				case <-stopChannel:
+					return
+				}
+			}
+		}(i)
+	}
+
+	for i := 0; i < chunkCount; i++ {
+		indexChannel <- i
+	}
+
+	for i := 0; i < chunkCount; i++ {
+		<-finishChannel
+	}
+
+	for i := 0; i < threads; i++ {
+		stopChannel <- 0
+	}
+}
+
+func Benchmark(localDirectory string, storage Storage, fileSize int64, chunkSize int, chunkCount int, uploadThreads int, downloadThreads int) bool {
+
+	filename := filepath.Join(localDirectory, "benchmark.dat")
+
+	defer func() {
+		os.Remove(filename)
+	}()
+
+	LOG_INFO("BENCHMARK_GENERATE", "Generating %s byte random data in memory", PrettySize(fileSize))
+	data := make([]byte, fileSize)
+	_, err := rand.Read(data)
+	if err != nil {
+		LOG_ERROR("BENCHMARK_RAND", "Failed to generate random data: %v", err)
+		return false
+	}
+
+	startTime := float64(time.Now().UnixNano()) / 1e9
+	LOG_INFO("BENCHMARK_WRITE", "Writing random data to local disk")
+	err = ioutil.WriteFile(filename, data, 0600)
+	if err != nil {
+		LOG_ERROR("BENCHMARK_WRITE", "Failed to write the random data: %v", err)
+		return false
+	}
+
+	runningTime := float64(time.Now().UnixNano())/1e9 - startTime
+	speed := int64(float64(fileSize) / runningTime)
+	LOG_INFO("BENCHMARK_WRITE", "Wrote %s bytes in %.2fs: %s/s", PrettySize(fileSize), runningTime, PrettySize(speed))
+
+	startTime = float64(time.Now().UnixNano()) / 1e9
+	LOG_INFO("BENCHMARK_READ", "Reading the random data from local disk")
+	file, err := os.Open(filename)
+	if err != nil {
+		LOG_ERROR("BENCHMARK_OPEN", "Failed to open the random data file: %v", err)
+		return false
+	}
+	segment := make([]byte, 1024*1024)
+	for err == nil {
+		_, err = file.Read(segment)
+	}
+	if err != io.EOF {
+		LOG_ERROR("BENCHMARK_OPEN", "Failed to read the random data file: %v", err)
+		return false
+	}
+	file.Close()
+	runningTime = float64(time.Now().UnixNano())/1e9 - startTime
+	speed = int64(float64(fileSize) / runningTime)
+	LOG_INFO("BENCHMARK_READ", "Read %s bytes in %.2fs: %s/s", PrettySize(fileSize), runningTime, PrettySize(speed))
+
+	buffer := bytes.NewReader(data)
+	benchmarkSplit(buffer, fileSize, chunkSize, false, false, "without compression/encryption")
+	benchmarkSplit(buffer, fileSize, chunkSize, true, false, "with compression but without encryption")
+	benchmarkSplit(buffer, fileSize, chunkSize, true, true, "with compression and encryption")
+
+	storage.CreateDirectory(0, "benchmark")
+	existingFiles, _, err := storage.ListFiles(0, "benchmark/")
+	if err != nil {
+		LOG_ERROR("BENCHMARK_LIST", "Failed to list the benchmark directory: %v", err)
+		return false
+	}
+
+	var existingChunks []string
+	for _, f := range existingFiles {
+		if len(f) > 0 && f[len(f)-1] != '/' {
+			existingChunks = append(existingChunks, "benchmark/"+f)
+		}
+	}
+
+	if len(existingChunks) > 0 {
+		LOG_INFO("BENCHMARK_DELETE", "Deleting %d temporary files from previous benchmark runs", len(existingChunks))
+		benchmarkRun(uploadThreads, len(existingChunks), func(threadIndex int, chunkIndex int) {
+			storage.DeleteFile(threadIndex, existingChunks[chunkIndex])
+		})
+	}
+
+	chunks := make([][]byte, chunkCount)
+	chunkHashes := make([]string, chunkCount)
+	LOG_INFO("BENCHMARK_GENERATE", "Generating %d chunks", chunkCount)
+	for i := 0; i < chunkCount; i++ {
+		chunks[i] = make([]byte, chunkSize)
+		_, err = rand.Read(chunks[i])
+		if err != nil {
+			LOG_ERROR("BENCHMARK_RAND", "Failed to generate random data: %v", err)
+			return false
+		}
+		hashInBytes := sha256.Sum256(chunks[i])
+		chunkHashes[i] = hex.EncodeToString(hashInBytes[:])
+
+	}
+
+	startTime = float64(time.Now().UnixNano()) / 1e9
+	benchmarkRun(uploadThreads, chunkCount, func(threadIndex int, chunkIndex int) {
+		err := storage.UploadFile(threadIndex, fmt.Sprintf("benchmark/chunk%d", chunkIndex), chunks[chunkIndex])
+		if err != nil {
+			LOG_ERROR("BENCHMARK_UPLOAD", "Failed to upload the chunk: %v", err)
+			return
+		}
+	})
+
+	runningTime = float64(time.Now().UnixNano())/1e9 - startTime
+	speed = int64(float64(chunkSize*chunkCount) / runningTime)
+	LOG_INFO("BENCHMARK_UPLOAD", "Uploaded %s bytes in %.2fs: %s/s", PrettySize(int64(chunkSize*chunkCount)), runningTime, PrettySize(speed))
+
+	config := CreateConfig()
+
+	startTime = float64(time.Now().UnixNano()) / 1e9
+	hashError := false
+	benchmarkRun(downloadThreads, chunkCount, func(threadIndex int, chunkIndex int) {
+		chunk := config.GetChunk()
+		chunk.Reset(false)
+		err := storage.DownloadFile(threadIndex, fmt.Sprintf("benchmark/chunk%d", chunkIndex), chunk)
+		if err != nil {
+			LOG_ERROR("BENCHMARK_DOWNLOAD", "Failed to download the chunk: %v", err)
+			return
+		}
+
+		hashInBytes := sha256.Sum256(chunk.GetBytes())
+		hash := hex.EncodeToString(hashInBytes[:])
+		if hash != chunkHashes[chunkIndex] {
+			LOG_WARN("BENCHMARK_HASH", "Chunk %d has mismatched hashes: %s != %s", chunkIndex, chunkHashes[chunkIndex], hash)
+			hashError = true
+		}
+
+		config.PutChunk(chunk)
+	})
+
+	runningTime = float64(time.Now().UnixNano())/1e9 - startTime
+	speed = int64(float64(chunkSize*chunkCount) / runningTime)
+	LOG_INFO("BENCHMARK_DOWNLOAD", "Downloaded %s bytes in %.2fs: %s/s", PrettySize(int64(chunkSize*chunkCount)), runningTime, PrettySize(speed))
+
+	if !hashError {
+		benchmarkRun(uploadThreads, chunkCount, func(threadIndex int, chunkIndex int) {
+			storage.DeleteFile(threadIndex, fmt.Sprintf("benchmark/chunk%d", chunkIndex))
+		})
+		LOG_INFO("BENCHMARK_DELETE", "Deleted %d temporary files from the storage", chunkCount)
+	}
+
+	return true
+}

src/duplicacy_chunk.go

@@ -5,18 +5,31 @@
 package duplicacy
 
 import (
-    "io"
+	"bytes"
+	"compress/zlib"
+	"crypto/aes"
+	"crypto/rsa"
+	"crypto/cipher"
+	"crypto/hmac"
+	"crypto/rand"
+	"crypto/sha256"
+	"encoding/hex"
+	"encoding/binary"
 	"fmt"
 	"hash"
-    "bytes"
+	"io"
+	"os"
 	"runtime"
-    "crypto/cipher"
-    "crypto/aes"
-    "crypto/rand"
-    "encoding/hex"
-    "compress/zlib"
 
 	"github.com/bkaradzic/go-lz4"
+	"github.com/minio/highwayhash"
+	"github.com/klauspost/reedsolomon"
+	"github.com/klauspost/compress/zstd"
+
+	// This is a fork of github.com/minio/highwayhash at 1.0.1 that computes incorrect hash on
+	// arm64 machines.  We need this fork to be able to read the chunks created by Duplicacy
+	// CLI 3.0.1 which unfortunately relies on incorrect hashes to determine if each shard is valid.
+	wronghighwayhash "github.com/gilbertchen/highwayhash"
 
 )
 
@@ -58,10 +71,20 @@ type Chunk struct {
 
 	config *Config // Every chunk is associated with a Config object.  Which hashing algorithm to use is determined
 	// by the config
+
+	isMetadata bool // Indicates if the chunk is a metadata chunk (instead of a file chunk).  This is primarily used by RSA
+	                // encryption, where a metadata chunk is not encrypted by RSA
+	
+	isBroken bool // Indicates the chunk did not download correctly. This is only used for -persist (allowFailures) mode
 }
 
 // Magic word to identify a duplicacy format encrypted file, plus a version number.
-var ENCRYPTION_HEADER = "duplicacy\000"
+var ENCRYPTION_BANNER = "duplicacy\000"
+
+// RSA encrypted chunks start with "duplicacy\002"
+var ENCRYPTION_VERSION_RSA byte = 2
+
+var ERASURE_CODING_BANNER = "duplicacy\003"
 
 // CreateChunk creates a new chunk.
 func CreateChunk(config *Config, bufferNeeded bool) *Chunk {
@@ -111,6 +134,8 @@ func (chunk *Chunk) Reset(hashNeeded bool) {
 	chunk.hash = nil
 	chunk.id = ""
 	chunk.size = 0
+	chunk.isMetadata = false
+	chunk.isBroken = false
 }
 
 // Write implements the Writer interface.
@@ -132,7 +157,7 @@ func (chunk *Chunk) Write(p []byte) (int, error){
 
 // GetHash returns the chunk hash.
 func (chunk *Chunk) GetHash() string {
-    if (len(chunk.hash) == 0) {
+	if len(chunk.hash) == 0 {
 		chunk.hash = chunk.hasher.Sum(nil)
 	}
 
@@ -168,7 +193,7 @@ func (chunk *Chunk) VerifyID() {
 
 // Encrypt encrypts the plain data stored in the chunk buffer.  If derivationKey is not nil, the actual
 // encryption key will be HMAC-SHA256(encryptionKey, derivationKey).
-func (chunk *Chunk) Encrypt(encryptionKey []byte, derivationKey string) (err error) {
+func (chunk *Chunk) Encrypt(encryptionKey []byte, derivationKey string, isMetadata bool) (err error) {
 
 	var aesBlock cipher.Block
 	var gcm cipher.AEAD
@@ -184,8 +209,17 @@ func (chunk *Chunk) Encrypt(encryptionKey []byte, derivationKey string) (err err
 	if len(encryptionKey) > 0 {
 
 		key := encryptionKey
-
-        if len(derivationKey) > 0 {
+		usingRSA := false
+		// Enable RSA encryption only when the chunk is not a metadata chunk
+		if chunk.config.rsaPublicKey != nil && !isMetadata && !chunk.isMetadata {
+			randomKey := make([]byte, 32)
+			_, err := rand.Read(randomKey)
+			if err != nil {
+				return err
+			}
+			key = randomKey
+			usingRSA = true
+		} else if len(derivationKey) > 0 {
 			hasher := chunk.config.NewKeyedHasher([]byte(derivationKey))
 			hasher.Write(encryptionKey)
 			key = hasher.Sum(nil)
@@ -202,7 +236,21 @@ func (chunk *Chunk) Encrypt(encryptionKey []byte, derivationKey string) (err err
 		}
 
 		// Start with the magic number and the version number.
-        encryptedBuffer.Write([]byte(ENCRYPTION_HEADER))
+		if usingRSA {
+			// RSA encryption starts "duplicacy\002"
+			encryptedBuffer.Write([]byte(ENCRYPTION_BANNER)[:len(ENCRYPTION_BANNER) - 1])
+			encryptedBuffer.Write([]byte{ENCRYPTION_VERSION_RSA})
+
+			// Then the encrypted key
+			encryptedKey, err := rsa.EncryptOAEP(sha256.New(), rand.Reader, chunk.config.rsaPublicKey, key, nil)
+			if err != nil {
+				return err
+			}
+			binary.Write(encryptedBuffer, binary.LittleEndian, uint16(len(encryptedKey)))
+			encryptedBuffer.Write(encryptedKey)
+		} else {
+			encryptedBuffer.Write([]byte(ENCRYPTION_BANNER))
+		}
 
 		// Followed by the nonce
 		nonce = make([]byte, gcm.NonceSize())
@@ -212,15 +260,46 @@ func (chunk *Chunk) Encrypt(encryptionKey []byte, derivationKey string) (err err
 		}
 		encryptedBuffer.Write(nonce)
 		offset = encryptedBuffer.Len()
-
 	}
 
-    // offset is either 0 or the length of header + nonce
+	// offset is either 0 or the length of banner + nonce
 
 	if chunk.config.CompressionLevel >= -1 && chunk.config.CompressionLevel <= 9 {
 		deflater, _ := zlib.NewWriterLevel(encryptedBuffer, chunk.config.CompressionLevel)
 		deflater.Write(chunk.buffer.Bytes())
 		deflater.Close()
+	} else if chunk.config.CompressionLevel >= ZSTD_COMPRESSION_LEVEL_FASTEST && chunk.config.CompressionLevel <= ZSTD_COMPRESSION_LEVEL_BEST  {
+		encryptedBuffer.Write([]byte("ZSTD"))
+
+		compressionLevel := zstd.SpeedDefault
+		if chunk.config.CompressionLevel == ZSTD_COMPRESSION_LEVEL_FASTEST {
+			compressionLevel = zstd.SpeedFastest
+		} else if chunk.config.CompressionLevel == ZSTD_COMPRESSION_LEVEL_BETTER {
+			compressionLevel = zstd.SpeedBetterCompression
+		} else if chunk.config.CompressionLevel == ZSTD_COMPRESSION_LEVEL_BEST {
+			compressionLevel = zstd.SpeedBestCompression
+		}
+
+		deflater, err := zstd.NewWriter(encryptedBuffer, zstd.WithEncoderLevel(compressionLevel))
+		if err != nil {
+			return err
+		}
+
+		// Make sure we have enough space in encryptedBuffer
+		availableLength := encryptedBuffer.Cap() - len(encryptedBuffer.Bytes())
+		maximumLength := deflater.MaxEncodedSize(chunk.buffer.Len())
+		if availableLength < maximumLength {
+			encryptedBuffer.Grow(maximumLength - availableLength)
+		}
+		_, err = deflater.Write(chunk.buffer.Bytes())
+		if err != nil {
+			return fmt.Errorf("ZSTD compression error: %v", err)
+		}
+
+		err = deflater.Close()
+		if err != nil {
+			return fmt.Errorf("ZSTD compression error: %v", err)
+		}
 	} else if chunk.config.CompressionLevel == DEFAULT_COMPRESSION_LEVEL {
 		encryptedBuffer.Write([]byte("LZ4 "))
 		// Make sure we have enough space in encryptedBuffer
@@ -240,38 +319,99 @@ func (chunk *Chunk) Encrypt(encryptionKey []byte, derivationKey string) (err err
 		return fmt.Errorf("Invalid compression level: %d", chunk.config.CompressionLevel)
 	}
 
-    if len(encryptionKey) == 0 {
-        chunk.buffer, encryptedBuffer = encryptedBuffer, chunk.buffer
-        return nil
-    }
+	if len(encryptionKey) > 0 {
 
-    // PKCS7 is used.  Compressed chunk sizes leaks information about the original chunks so we want the padding sizes
+		// PKCS7 is used.  The sizes of compressed chunks leak information about the original chunks so we want the padding sizes
 		// to be the maximum allowed by PKCS7
 		dataLength := encryptedBuffer.Len() - offset
-    paddingLength := dataLength % 256
-    if paddingLength == 0 {
-        paddingLength = 256
-    }
+		paddingLength := 256 - dataLength%256
 
 		encryptedBuffer.Write(bytes.Repeat([]byte{byte(paddingLength)}, paddingLength))
 		encryptedBuffer.Write(bytes.Repeat([]byte{0}, gcm.Overhead()))
 
-    // The encrypted data will be appended to the duplicacy header and the once.
+		// The encrypted data will be appended to the duplicacy banner and the once.
 		encryptedBytes := gcm.Seal(encryptedBuffer.Bytes()[:offset], nonce,
 			encryptedBuffer.Bytes()[offset:offset+dataLength+paddingLength], nil)
 
 		encryptedBuffer.Truncate(len(encryptedBytes))
+	}
 
+	if chunk.config.DataShards == 0 || chunk.config.ParityShards == 0 {
 		chunk.buffer, encryptedBuffer = encryptedBuffer, chunk.buffer
+		return
+	}
+
+	// Start erasure coding
+	encoder, err := reedsolomon.New(chunk.config.DataShards, chunk.config.ParityShards)
+	if err != nil {
+		return err
+	}
+	chunkSize := len(encryptedBuffer.Bytes())
+	shardSize := (chunkSize + chunk.config.DataShards - 1) / chunk.config.DataShards
+	// Append zeros to make the last shard to have the same size as other
+	encryptedBuffer.Write(make([]byte, shardSize * chunk.config.DataShards - chunkSize))
+	// Grow the buffer for parity shards
+	encryptedBuffer.Grow(shardSize * chunk.config.ParityShards)
+	// Now create one slice for each shard, reusing the data in the buffer
+	data := make([][]byte, chunk.config.DataShards + chunk.config.ParityShards)
+	for i := 0; i < chunk.config.DataShards + chunk.config.ParityShards; i++ {
+		data[i] = encryptedBuffer.Bytes()[i * shardSize: (i + 1) * shardSize]
+	}
+	// This populates the parity shard
+	encoder.Encode(data)
+
+	// Prepare the chunk to be uploaded
+	chunk.buffer.Reset()
+	// First the banner
+	chunk.buffer.Write([]byte(ERASURE_CODING_BANNER))
+	// Then the header which includes the chunk size, data/parity and a 2-byte checksum
+	header := make([]byte, 14)
+	binary.LittleEndian.PutUint64(header[0:], uint64(chunkSize))
+	binary.LittleEndian.PutUint16(header[8:], uint16(chunk.config.DataShards))
+	binary.LittleEndian.PutUint16(header[10:], uint16(chunk.config.ParityShards))
+	header[12] = header[0] ^ header[2] ^ header[4] ^ header[6] ^ header[8] ^ header[10]
+	header[13] = header[1] ^ header[3] ^ header[5] ^ header[7] ^ header[9] ^ header[11]
+	chunk.buffer.Write(header)
+	// Calculate the highway hash for each shard
+	hashKey := make([]byte, 32)
+	for _, part := range data {
+		hasher, err := highwayhash.New(hashKey)
+		if err != nil {
+			return err
+		}
+		_, err = hasher.Write(part)
+		if err != nil {
+			return err
+		}
+		chunk.buffer.Write(hasher.Sum(nil))
+	}
+
+	// Copy the data
+	for _, part := range data {
+		chunk.buffer.Write(part)
+	}
+	// Append the header again for redundancy
+	chunk.buffer.Write(header)
 
 	return nil
+}
 
+// This is to ensure compatibility with Vertical Backup, which still uses HMAC-SHA256 (instead of HMAC-BLAKE2) to
+// derive the key used to encrypt/decrypt files and chunks.
+
+var DecryptWithHMACSHA256 = false
+
+func init() {
+	if value, found := os.LookupEnv("DUPLICACY_DECRYPT_WITH_HMACSHA256"); found && value != "0" {
+		DecryptWithHMACSHA256 = true
+	}
 }
 
 // Decrypt decrypts the encrypted data stored in the chunk buffer.  If derivationKey is not nil, the actual
 // encryption key will be HMAC-SHA256(encryptionKey, derivationKey).
-func (chunk *Chunk) Decrypt(encryptionKey []byte, derivationKey string) (err error) {
+func (chunk *Chunk) Decrypt(encryptionKey []byte, derivationKey string) (err error, rewriteNeeded bool) {
 
+	rewriteNeeded = false
 	var offset int
 
 	encryptedBuffer := AllocateChunkBuffer()
@@ -281,49 +421,213 @@ func (chunk *Chunk) Decrypt(encryptionKey []byte, derivationKey string) (err err
 	}()
 
 	chunk.buffer, encryptedBuffer = encryptedBuffer, chunk.buffer
+	bannerLength := len(ENCRYPTION_BANNER)
+
+	if len(encryptedBuffer.Bytes()) > bannerLength && string(encryptedBuffer.Bytes()[:bannerLength]) == ERASURE_CODING_BANNER {
+
+		// The chunk was encoded with erasure coding
+		if len(encryptedBuffer.Bytes()) < bannerLength + 14 {
+			return fmt.Errorf("Erasure coding header truncated (%d bytes)", len(encryptedBuffer.Bytes())), false
+		}
+		// Check the header checksum
+		header := encryptedBuffer.Bytes()[bannerLength: bannerLength + 14]
+		if header[12] != header[0] ^ header[2] ^ header[4] ^ header[6] ^ header[8] ^ header[10] ||
+		   header[13] != header[1] ^ header[3] ^ header[5] ^ header[7] ^ header[9] ^ header[11] {
+			return fmt.Errorf("Erasure coding header corrupted (%x)", header), false
+		}
+
+		// Read the parameters
+		chunkSize := int(binary.LittleEndian.Uint64(header[0:8]))
+		dataShards := int(binary.LittleEndian.Uint16(header[8:10]))
+		parityShards := int(binary.LittleEndian.Uint16(header[10:12]))
+		shardSize := (chunkSize + chunk.config.DataShards - 1) / chunk.config.DataShards
+		// This is the length the chunk file should have
+		expectedLength := bannerLength + 2 * len(header) + (dataShards + parityShards) * (shardSize + 32)
+		// The minimum length that can be recovered from
+		minimumLength := bannerLength + len(header) + (dataShards + parityShards) * 32 + dataShards * shardSize
+		LOG_DEBUG("CHUNK_ERASURECODE", "Chunk size: %d bytes, data size: %d, parity: %d/%d", chunkSize, len(encryptedBuffer.Bytes()), dataShards, parityShards)
+		if len(encryptedBuffer.Bytes()) > expectedLength {
+			LOG_WARN("CHUNK_ERASURECODE", "Chunk has %d bytes (instead of %d)", len(encryptedBuffer.Bytes()), expectedLength)
+		} else if len(encryptedBuffer.Bytes()) == expectedLength {
+			// Correct size; fall through
+		} else if len(encryptedBuffer.Bytes()) > minimumLength {
+			LOG_WARN("CHUNK_ERASURECODE", "Chunk is truncated (%d out of %d bytes)", len(encryptedBuffer.Bytes()), expectedLength)
+		} else {
+			return fmt.Errorf("Not enough chunk data for recovery; chunk size: %d bytes, data size: %d, parity: %d/%d", chunkSize, len(encryptedBuffer.Bytes()), dataShards, parityShards), false
+		}
+
+		// Where the hashes start
+		hashOffset := bannerLength + len(header)
+		// Where the data start
+		dataOffset := hashOffset + (dataShards + parityShards) * 32
+
+		data := make([][]byte, dataShards + parityShards)
+		recoveryNeeded := false
+		hashKey := make([]byte, 32)
+		availableShards := 0
+		wrongHashDetected := false
+
+		for i := 0; i < dataShards + parityShards; i++ {
+			start := dataOffset + i * shardSize
+			if start + shardSize > len(encryptedBuffer.Bytes()) {
+				// the current shard is incomplete
+				break
+			}
+			// Now verify the hash
+			hasher, err := highwayhash.New(hashKey)
+			if err != nil {
+				return err, false
+			}
+			_, err = hasher.Write(encryptedBuffer.Bytes()[start: start + shardSize])
+			if err != nil {
+				return err, false
+			}
+
+			matched := bytes.Compare(hasher.Sum(nil), encryptedBuffer.Bytes()[hashOffset + i * 32: hashOffset + (i + 1) * 32]) == 0
+
+			if !matched && runtime.GOARCH == "arm64" {
+				hasher, err := wronghighwayhash.New(hashKey)
+				if err == nil {
+					_, err = hasher.Write(encryptedBuffer.Bytes()[start: start + shardSize])
+					if err == nil {
+						matched = bytes.Compare(hasher.Sum(nil), encryptedBuffer.Bytes()[hashOffset + i * 32: hashOffset + (i + 1) * 32]) == 0
+						if matched && !wrongHashDetected {
+							LOG_WARN("CHUNK_ERASURECODE", "Hash for shard %d was calculated with a wrong version of highwayhash", i)
+							wrongHashDetected = true
+							rewriteNeeded = true
+						}
+					}
+				}
+			}
+
+			if !matched {
+				if i < dataShards {
+					recoveryNeeded = true
+					rewriteNeeded = true
+				}
+			} else {
+				// The shard is good
+				data[i] = encryptedBuffer.Bytes()[start: start + shardSize]
+				availableShards++
+				if availableShards >= dataShards {
+					// We have enough shards to recover; skip the remaining shards
+					break
+				}
+			}
+		}
+
+		if !recoveryNeeded {
+			// Remove the padding zeros from the last shard
+			encryptedBuffer.Truncate(dataOffset + chunkSize)
+			// Skip the header and hashes
+			encryptedBuffer.Read(encryptedBuffer.Bytes()[:dataOffset])
+		} else {
+			if availableShards < dataShards {
+				return fmt.Errorf("Not enough chunk data for recover; only %d out of %d shards are complete", availableShards, dataShards + parityShards), false
+			}
+
+			// Show the validity of shards using a string of * and -
+			slots := ""
+			for _, part := range data {
+				if len(part) != 0 {
+					slots += "*"
+				} else {
+					slots += "-"
+				}
+			}
+
+			LOG_WARN("CHUNK_ERASURECODE", "Recovering a %d byte chunk from %d byte shards: %s", chunkSize, shardSize, slots)
+			encoder, err := reedsolomon.New(dataShards, parityShards)
+			if err != nil {
+				return err, false
+			}
+			err = encoder.Reconstruct(data)
+			if err != nil {
+				return err, false
+			}
+			LOG_DEBUG("CHUNK_ERASURECODE", "Chunk data successfully recovered")
+			buffer := AllocateChunkBuffer()
+			buffer.Reset()
+			for i := 0; i < dataShards; i++ {
+				buffer.Write(data[i])
+			}
+			buffer.Truncate(chunkSize)
+
+			ReleaseChunkBuffer(encryptedBuffer)
+			encryptedBuffer = buffer
+		}
+
+	}
 
 	if len(encryptionKey) > 0 {
 
 		key := encryptionKey
 
 		if len(derivationKey) > 0 {
-            hasher := chunk.config.NewKeyedHasher([]byte(derivationKey))
+			var hasher hash.Hash
+			if DecryptWithHMACSHA256 {
+				hasher = hmac.New(sha256.New, []byte(derivationKey))
+			} else {
+				hasher = chunk.config.NewKeyedHasher([]byte(derivationKey))
+			}
+
 			hasher.Write(encryptionKey)
 			key = hasher.Sum(nil)
 		}
 
+		if len(encryptedBuffer.Bytes()) < bannerLength + 12 {
+			return fmt.Errorf("No enough encrypted data (%d bytes) provided", len(encryptedBuffer.Bytes())), false
+		}
+
+		if string(encryptedBuffer.Bytes()[:bannerLength-1]) != ENCRYPTION_BANNER[:bannerLength-1] {
+			return fmt.Errorf("The storage doesn't seem to be encrypted"), false
+		}
+
+		encryptionVersion := encryptedBuffer.Bytes()[bannerLength-1]
+		if encryptionVersion != 0 && encryptionVersion != ENCRYPTION_VERSION_RSA {
+			return fmt.Errorf("Unsupported encryption version %d", encryptionVersion), false
+		}
+
+		if encryptionVersion == ENCRYPTION_VERSION_RSA {
+			if chunk.config.rsaPrivateKey == nil {
+				LOG_ERROR("CHUNK_DECRYPT", "An RSA private key is required to decrypt the chunk")
+				return fmt.Errorf("An RSA private key is required to decrypt the chunk"), false
+			}
+
+			encryptedKeyLength := binary.LittleEndian.Uint16(encryptedBuffer.Bytes()[bannerLength:bannerLength+2])
+
+			if len(encryptedBuffer.Bytes()) < bannerLength + 14 + int(encryptedKeyLength) {
+				return fmt.Errorf("No enough encrypted data (%d bytes) provided", len(encryptedBuffer.Bytes())), false
+			}
+
+			encryptedKey := encryptedBuffer.Bytes()[bannerLength + 2:bannerLength + 2 + int(encryptedKeyLength)]
+			bannerLength += 2 + int(encryptedKeyLength)
+
+			decryptedKey, err := rsa.DecryptOAEP(sha256.New(), rand.Reader, chunk.config.rsaPrivateKey, encryptedKey, nil)
+			if err != nil {
+				return err, false
+			}
+			key = decryptedKey
+		}
+
 		aesBlock, err := aes.NewCipher(key)
 		if err != nil {
-            return err
+			return err, false
 		}
 
 		gcm, err := cipher.NewGCM(aesBlock)
 		if err != nil {
-            return err
+			return err, false
 		}
 
-        headerLength := len(ENCRYPTION_HEADER)
-        offset = headerLength + gcm.NonceSize()
-
-        if len(encryptedBuffer.Bytes()) < offset {
-            return fmt.Errorf("No enough encrypted data (%d bytes) provided", len(encryptedBuffer.Bytes()))
-        }
-
-        if string(encryptedBuffer.Bytes()[:headerLength - 1]) != ENCRYPTION_HEADER[:headerLength - 1] {
-            return fmt.Errorf("The storage doesn't seem to be encrypted")
-        }
-
-        if encryptedBuffer.Bytes()[headerLength - 1] != 0 {
-            return fmt.Errorf("Unsupported encryption version %d", encryptedBuffer.Bytes()[headerLength - 1])
-        }
-
-        nonce := encryptedBuffer.Bytes()[headerLength: offset]
+		offset = bannerLength + gcm.NonceSize()
+		nonce := encryptedBuffer.Bytes()[bannerLength:offset]
 
 		decryptedBytes, err := gcm.Open(encryptedBuffer.Bytes()[:offset], nonce,
 			encryptedBuffer.Bytes()[offset:], nil)
 
 		if err != nil {
-            return err
+			return err, false
 		}
 
 		paddingLength := int(decryptedBytes[len(decryptedBytes)-1])
@@ -331,14 +635,14 @@ func (chunk *Chunk) Decrypt(encryptionKey []byte, derivationKey string) (err err
 			paddingLength = 256
 		}
 		if len(decryptedBytes) <= paddingLength {
-            return fmt.Errorf("Incorrect padding length %d out of %d bytes", paddingLength, len(decryptedBytes))
+			return fmt.Errorf("Incorrect padding length %d out of %d bytes", paddingLength, len(decryptedBytes)), false
 		}
 
 		for i := 0; i < paddingLength; i++ {
 			padding := decryptedBytes[len(decryptedBytes)-1-i]
 			if padding != byte(paddingLength) {
 				return fmt.Errorf("Incorrect padding of length %d: %x", paddingLength,
-                                  decryptedBytes[len(decryptedBytes) - paddingLength:])
+					decryptedBytes[len(decryptedBytes)-paddingLength:]), false
 			}
 		}
 
@@ -352,18 +656,36 @@ func (chunk *Chunk) Decrypt(encryptionKey []byte, derivationKey string) (err err
 		chunk.buffer.Reset()
 		decompressed, err := lz4.Decode(chunk.buffer.Bytes(), encryptedBuffer.Bytes()[4:])
 		if err != nil {
-            return err
+			return err, false
 		}
 
 		chunk.buffer.Write(decompressed)
 		chunk.hasher = chunk.config.NewKeyedHasher(chunk.config.HashKey)
 		chunk.hasher.Write(decompressed)
 		chunk.hash = nil
-        return nil
+		return nil, rewriteNeeded
 	}
+
+	if len(compressed) > 4 && string(compressed[:4]) == "ZSTD" {
+		chunk.buffer.Reset()
+		chunk.hasher = chunk.config.NewKeyedHasher(chunk.config.HashKey)
+		chunk.hash = nil
+
+		encryptedBuffer.Read(encryptedBuffer.Bytes()[:4])
+		inflater, err := zstd.NewReader(encryptedBuffer)
+		if err != nil {
+			return err, false
+		}
+		defer inflater.Close()
+		if _, err = io.Copy(chunk, inflater); err != nil {
+			return err, false
+		}
+		return nil, rewriteNeeded
+	}
+
 	inflater, err := zlib.NewReader(encryptedBuffer)
 	if err != nil {
-        return err
+		return err, false
 	}
 
 	defer inflater.Close()
@@ -373,10 +695,9 @@ func (chunk *Chunk) Decrypt(encryptionKey []byte, derivationKey string) (err err
 	chunk.hash = nil
 
 	if _, err = io.Copy(chunk, inflater); err != nil {
-        return err
+		return err, false
 	}
 
-    return nil
+	return nil, rewriteNeeded
 
 }
-

src/duplicacy_chunk_test.go

@@ -5,13 +5,53 @@
 package duplicacy
 
 import (
-    "testing"
 	"bytes"
 	crypto_rand "crypto/rand"
+	"crypto/rsa"
 	"math/rand"
+	"testing"
 )
 
-func TestChunk(t *testing.T) {
+func TestErasureCoding(t *testing.T) {
+	key := []byte("duplicacydefault")
+
+	config := CreateConfig()
+	config.HashKey = key
+	config.IDKey = key
+	config.MinimumChunkSize = 100
+	config.CompressionLevel = DEFAULT_COMPRESSION_LEVEL
+	config.DataShards = 5
+    config.ParityShards = 2
+
+	chunk := CreateChunk(config, true)
+	chunk.Reset(true)
+	data := make([]byte, 100)
+	for i := 0; i < len(data); i++ {
+		data[i] = byte(i)
+	}
+	chunk.Write(data)
+	err := chunk.Encrypt([]byte(""), "", false)
+	if err != nil {
+		t.Errorf("Failed to encrypt the test data: %v", err)
+		return
+	}
+
+	encryptedData := make([]byte, chunk.GetLength())
+	copy(encryptedData, chunk.GetBytes())
+
+	crypto_rand.Read(encryptedData[280:300])
+
+	chunk.Reset(false)
+	chunk.Write(encryptedData)
+	err, _ = chunk.Decrypt([]byte(""), "")
+	if err != nil {
+		t.Errorf("Failed to decrypt the data: %v", err)
+		return
+	}
+	return
+}
+
+func TestChunkBasic(t *testing.T) {
 
 	key := []byte("duplicacydefault")
 
@@ -22,6 +62,20 @@ func TestChunk(t *testing.T) {
 	config.CompressionLevel = DEFAULT_COMPRESSION_LEVEL
 	maxSize := 1000000
 
+	if *testRSAEncryption {
+		privateKey, err := rsa.GenerateKey(crypto_rand.Reader, 2048)
+		if err != nil {
+			t.Errorf("Failed to generate a random private key: %v", err)
+		}
+		config.rsaPrivateKey = privateKey
+		config.rsaPublicKey = privateKey.Public().(*rsa.PublicKey)
+	}
+
+	if *testErasureCoding {
+		config.DataShards = 5
+		config.ParityShards = 2
+	}
+
 	for i := 0; i < 500; i++ {
 
 		size := rand.Int() % maxSize
@@ -35,7 +89,7 @@ func TestChunk(t *testing.T) {
 		hash := chunk.GetHash()
 		id := chunk.GetID()
 
-        err := chunk.Encrypt(key, "")
+		err := chunk.Encrypt(key, "", false)
 		if err != nil {
 			t.Errorf("Failed to encrypt the data: %v", err)
 			continue
@@ -44,9 +98,19 @@ func TestChunk(t *testing.T) {
 		encryptedData := make([]byte, chunk.GetLength())
 		copy(encryptedData, chunk.GetBytes())
 
+		if *testErasureCoding {
+			offset := 24 + 32 * 7
+			start := rand.Int() % (len(encryptedData) - offset) + offset
+			length := (len(encryptedData) - offset) / 7
+			if start + length > len(encryptedData) {
+				length = len(encryptedData) - start
+			}
+			crypto_rand.Read(encryptedData[start: start+length])
+		}
+
 		chunk.Reset(false)
 		chunk.Write(encryptedData)
-        err = chunk.Decrypt(key, "")
+		err, _ = chunk.Decrypt(key, "")
 		if err != nil {
 			t.Errorf("Failed to decrypt the data: %v", err)
 			continue
@@ -63,11 +127,10 @@ func TestChunk(t *testing.T) {
 		}
 
 		if bytes.Compare(plainData, decryptedData) != 0 {
-            t.Logf("orginal length: %d, decrypted length: %d", len(plainData), len(decryptedData))
+			t.Logf("Original length: %d, decrypted length: %d", len(plainData), len(decryptedData))
 			t.Errorf("Original data:\n%x\nDecrypted data:\n%x\n", plainData, decryptedData)
 		}
 
-
 	}
 
 }

src/duplicacy_chunkdownloader.go

@@ -19,73 +19,47 @@ type ChunkDownloadTask struct {
 	isDownloading bool   // 'true' means the chunk has been downloaded or is being downloaded
 }
 
-// ChunkDownloadCompletion represents the nofication when a chunk has been downloaded.
 type ChunkDownloadCompletion struct {
-    chunkIndex int              // The index of this chunk in the chunk list
-    chunk *Chunk                // The chunk that has been downloaded
+	chunk      *Chunk
+	chunkIndex int
 }
 
-// ChunkDownloader is capable of performing multi-threaded downloading.  Chunks to be downloaded are first organized
+// ChunkDownloader is a wrapper of ChunkOperator and is only used by the restore procedure.capable of performing multi-threaded downloading.  Chunks to be downloaded are first organized
 // as a list of ChunkDownloadTasks, with only the chunkHash field initialized.  When a chunk is needed, the
 // corresponding ChunkDownloadTask is sent to the dowloading goroutine.  Once a chunk is downloaded, it will be
 // inserted in the completed task list.
 type ChunkDownloader struct {
-    config *Config                                     // Associated config
-    storage Storage                                    // Download from this storage
-    snapshotCache *FileStorage                         // Used as cache if not nil; usually for downloading snapshot chunks
-    showStatistics bool                                // Show a stats log for each chunk if true
-    threads int                                        // Number of threads
+
+	operator                  *ChunkOperator
+
+	totalChunkSize            int64 // Total chunk size
+	downloadedChunkSize       int64 // Downloaded chunk size
 
 	taskList       []ChunkDownloadTask // The list of chunks to be downloaded
 	completedTasks map[int]bool        // Store downloaded chunks
 	lastChunkIndex int                 // a monotonically increasing number indicating the last chunk to be downloaded
 
-    taskQueue chan ChunkDownloadTask                   // Downloading goroutines are waiting on this channel for input
-    stopChannel chan bool                              // Used to stop the dowloading goroutines
 	completionChannel chan ChunkDownloadCompletion // A downloading goroutine sends back the chunk via this channel after downloading
 
 	startTime                 int64 // The time it starts downloading
-    totalChunkSize int64                               // Total chunk size
-    downloadedChunkSize int64                          // Downloaded chunk size
 	numberOfDownloadedChunks  int   // The number of chunks that have been downloaded
 	numberOfDownloadingChunks int   // The number of chunks still being downloaded
 	numberOfActiveChunks      int   // The number of chunks that is being downloaded or has been downloaded but not reclaimed
 }
 
-func CreateChunkDownloader(config *Config, storage Storage, snapshotCache *FileStorage, showStatistics bool, threads int) *ChunkDownloader {
+func CreateChunkDownloader(operator *ChunkOperator) *ChunkDownloader {
 	downloader := &ChunkDownloader{
-        config: config,
-        storage: storage,
-        snapshotCache: snapshotCache,
-        showStatistics: showStatistics,
-        threads: threads,
+		operator:       operator,
 
 		taskList:       nil,
 		completedTasks: make(map[int]bool),
 		lastChunkIndex: 0,
 
-        taskQueue: make(chan ChunkDownloadTask, threads),
-        stopChannel: make(chan bool),
 		completionChannel: make(chan ChunkDownloadCompletion),
 
 		startTime: time.Now().Unix(),
 	}
 
-    // Start the downloading goroutines
-    for i := 0; i < downloader.threads; i++ {
-        go func(threadIndex int) {
-            defer CatchLogException()
-            for {
-                select {
-                case task := <- downloader.taskQueue:
-                    downloader.Download(threadIndex, task)
-                case <- downloader.stopChannel:
-                    return
-                }
-            }
-        } (i)
-    }
-
 	return downloader
 }
 
@@ -121,25 +95,7 @@ func (downloader *ChunkDownloader) AddFiles(snapshot *Snapshot, files [] *Entry)
 			maximumChunks = file.EndChunk - file.StartChunk
 		}
 	}
-}
-
-// AddChunk adds a single chunk the download list.
-func (downloader *ChunkDownloader) AddChunk(chunkHash string) int {
-    task := ChunkDownloadTask {
-        chunkIndex: len(downloader.taskList),
-        chunkHash: chunkHash,
-        chunkLength: 0,
-        needed: true,
-        isDownloading: false,
-    }
-    downloader.taskList = append(downloader.taskList, task)
-    if downloader.numberOfActiveChunks < downloader.threads {
-        downloader.taskQueue <- task
-        downloader.numberOfDownloadingChunks++
-        downloader.numberOfActiveChunks++
-        downloader.taskList[len(downloader.taskList) - 1].isDownloading = true
-    }
-    return len(downloader.taskList) - 1
+	downloader.operator.totalChunkSize = downloader.totalChunkSize
 }
 
 // Prefetch adds up to 'threads' chunks needed by a file to the download list
@@ -152,20 +108,22 @@ func (downloader *ChunkDownloader) Prefetch(file *Entry) {
 		task := &downloader.taskList[i]
 		if task.needed {
 			if !task.isDownloading {
-                if downloader.numberOfActiveChunks >= downloader.threads {
+				if downloader.numberOfActiveChunks >= downloader.operator.threads {
 					return
 				}
 
 				LOG_DEBUG("DOWNLOAD_PREFETCH", "Prefetching %s chunk %s", file.Path,
-                          downloader.config.GetChunkIDFromHash(task.chunkHash))
-                downloader.taskQueue <- *task
+					downloader.operator.config.GetChunkIDFromHash(task.chunkHash))
+				downloader.operator.DownloadAsync(task.chunkHash, i, false, func (chunk *Chunk, chunkIndex int) {
+					downloader.completionChannel <- ChunkDownloadCompletion { chunk: chunk, chunkIndex: chunkIndex }
+				})
 				task.isDownloading = true
 				downloader.numberOfDownloadingChunks++
 				downloader.numberOfActiveChunks++
 			}
 		} else {
 			LOG_DEBUG("DOWNLOAD_PREFETCH", "%s chunk %s is not needed", file.Path,
-                      downloader.config.GetChunkIDFromHash(task.chunkHash))
+				downloader.operator.config.GetChunkIDFromHash(task.chunkHash))
 		}
 	}
 }
@@ -173,33 +131,52 @@ func (downloader *ChunkDownloader) Prefetch(file *Entry) {
 // Reclaim releases the downloaded chunk to the chunk pool
 func (downloader *ChunkDownloader) Reclaim(chunkIndex int) {
 
-    if downloader.lastChunkIndex == chunkIndex {
+	if downloader.lastChunkIndex >= chunkIndex {
 		return
 	}
 
-    for i, _ := range downloader.completedTasks {
+	for i := range downloader.completedTasks {
 		if i < chunkIndex && downloader.taskList[i].chunk != nil {
-            downloader.config.PutChunk(downloader.taskList[i].chunk)
+			downloader.operator.config.PutChunk(downloader.taskList[i].chunk)
 			downloader.taskList[i].chunk = nil
 			delete(downloader.completedTasks, i)
 			downloader.numberOfActiveChunks--
 		}
 	}
 
+	for i := downloader.lastChunkIndex; i < chunkIndex; i++ {
+		// These chunks are never downloaded if 'isDownloading' is false; note that 'isDownloading' isn't reset to
+		// false after a chunk has been downloaded
+		if !downloader.taskList[i].isDownloading {
+			atomic.AddInt64(&downloader.totalChunkSize, -int64(downloader.taskList[i].chunkLength))
+		}
+	}
 	downloader.lastChunkIndex = chunkIndex
 }
 
+// Return the chunk last downloaded and its hash
+func (downloader *ChunkDownloader) GetLastDownloadedChunk() (chunk *Chunk, chunkHash string) {
+	if downloader.lastChunkIndex >= len(downloader.taskList) {
+		return nil, ""
+	}
+
+	task := downloader.taskList[downloader.lastChunkIndex]
+	return task.chunk, task.chunkHash
+}
+
 // WaitForChunk waits until the specified chunk is ready
 func (downloader *ChunkDownloader) WaitForChunk(chunkIndex int) (chunk *Chunk) {
 
-    // Reclain any chunk not needed
+	// Reclaim any chunk not needed
 	downloader.Reclaim(chunkIndex)
 
 	// If we haven't started download the specified chunk, download it now
 	if !downloader.taskList[chunkIndex].isDownloading {
 		LOG_DEBUG("DOWNLOAD_FETCH", "Fetching chunk %s",
-                  downloader.config.GetChunkIDFromHash(downloader.taskList[chunkIndex].chunkHash))
-        downloader.taskQueue <- downloader.taskList[chunkIndex]
+			downloader.operator.config.GetChunkIDFromHash(downloader.taskList[chunkIndex].chunkHash))
+		downloader.operator.DownloadAsync(downloader.taskList[chunkIndex].chunkHash, chunkIndex, false, func (chunk *Chunk, chunkIndex int) {
+			downloader.completionChannel <- ChunkDownloadCompletion { chunk: chunk, chunkIndex: chunkIndex }
+		})
 		downloader.taskList[chunkIndex].isDownloading = true
 		downloader.numberOfDownloadingChunks++
 		downloader.numberOfActiveChunks++
@@ -207,7 +184,7 @@ func (downloader *ChunkDownloader) WaitForChunk(chunkIndex int) (chunk *Chunk) {
 
 	// We also need to look ahead and prefetch other chunks as many as permitted by the number of threads
 	for i := chunkIndex + 1; i < len(downloader.taskList); i++ {
-        if downloader.numberOfActiveChunks >= downloader.threads {
+		if downloader.numberOfActiveChunks >= downloader.operator.threads {
 			break
 		}
 		task := &downloader.taskList[i]
@@ -216,8 +193,10 @@ func (downloader *ChunkDownloader) WaitForChunk(chunkIndex int) (chunk *Chunk) {
 		}
 
 		if !task.isDownloading {
-            LOG_DEBUG("DOWNLOAD_PREFETCH", "Prefetching chunk %s", downloader.config.GetChunkIDFromHash(task.chunkHash))
-            downloader.taskQueue <- *task
+			LOG_DEBUG("DOWNLOAD_PREFETCH", "Prefetching chunk %s", downloader.operator.config.GetChunkIDFromHash(task.chunkHash))
+			downloader.operator.DownloadAsync(task.chunkHash, task.chunkIndex, false, func (chunk *Chunk, chunkIndex int) {
+				downloader.completionChannel <- ChunkDownloadCompletion { chunk: chunk, chunkIndex: chunkIndex }
+			})
 			task.isDownloading = true
 			downloader.numberOfDownloadingChunks++
 			downloader.numberOfActiveChunks++
@@ -235,139 +214,45 @@ func (downloader *ChunkDownloader) WaitForChunk(chunkIndex int) (chunk *Chunk) {
 	return downloader.taskList[chunkIndex].chunk
 }
 
-// Stop terminates all downloading goroutines
-func (downloader *ChunkDownloader) Stop() {
-    for downloader.numberOfDownloadingChunks > 0 {
+// WaitForCompletion waits until all chunks have been downloaded
+func (downloader *ChunkDownloader) WaitForCompletion() {
+
+	// Tasks in completedTasks have not been counted by numberOfActiveChunks
+	downloader.numberOfActiveChunks -= len(downloader.completedTasks)
+
+	// find the completed task with the largest index; we'll start from the next index
+	for index := range downloader.completedTasks {
+		if downloader.lastChunkIndex < index {
+			downloader.lastChunkIndex = index
+		}
+	}
+
+	// Looping until there isn't a download task in progress
+	for downloader.numberOfActiveChunks > 0 || downloader.lastChunkIndex + 1 < len(downloader.taskList) {
+
+		// Wait for a completion event first
+		if downloader.numberOfActiveChunks > 0 {
 			completion := <-downloader.completionChannel
-        downloader.completedTasks[completion.chunkIndex] = true
-        downloader.taskList[completion.chunkIndex].chunk = completion.chunk
+			downloader.operator.config.PutChunk(completion.chunk)
+			downloader.numberOfActiveChunks--
 			downloader.numberOfDownloadedChunks++
 			downloader.numberOfDownloadingChunks--
 		}
 
-    for i, _ := range downloader.completedTasks {
-        downloader.config.PutChunk(downloader.taskList[i].chunk)
-        downloader.taskList[i].chunk = nil
-        downloader.numberOfActiveChunks--
+		// Pass the tasks one by one to the download queue
+		if downloader.lastChunkIndex + 1 < len(downloader.taskList) {
+			task := &downloader.taskList[downloader.lastChunkIndex + 1]
+			if task.isDownloading {
+				downloader.lastChunkIndex++
+				continue
 			}
-
-    for i := 0; i < downloader.threads; i++ {
-        downloader.stopChannel <- true
-    }
-}
-
-// Download downloads a chunk from the storage.
-func (downloader *ChunkDownloader) Download(threadIndex int, task ChunkDownloadTask) bool {
-
-    cachedPath := ""
-    chunk := downloader.config.GetChunk()
-    chunkID := downloader.config.GetChunkIDFromHash(task.chunkHash)
-
-    if downloader.snapshotCache != nil && downloader.storage.IsCacheNeeded() {
-
-        var exist bool
-        var err error
-
-        // Reset the chunk with a hasher -- we're reading from the cache where chunk are not encrypted or compressed
-        chunk.Reset(true)
-
-        cachedPath, exist, _, err = downloader.snapshotCache.FindChunk(threadIndex, chunkID, false)
-        if err != nil {
-            LOG_WARN("DOWNLOAD_CACHE", "Failed to find the cache path for the chunk %s: %v", chunkID, err)
-        } else if exist {
-            err = downloader.snapshotCache.DownloadFile(0, cachedPath, chunk)
-            if err != nil {
-                LOG_WARN("DOWNLOAD_CACHE", "Failed to load the chunk %s from the snapshot cache: %v", chunkID, err)
-            } else {
-                actualChunkID := chunk.GetID()
-                if actualChunkID != chunkID {
-                    LOG_WARN("DOWNLOAD_CACHE_CORRUPTED",
-                             "The chunk %s load from the snapshot cache has a hash id of %s", chunkID, actualChunkID)
-                } else {
-                    LOG_DEBUG("CHUNK_CACHE", "Chunk %s has been loaded from the snapshot cache", chunkID)
-
-                    downloader.completionChannel <- ChunkDownloadCompletion{ chunk: chunk, chunkIndex:task.chunkIndex }
-                    return false
+			downloader.operator.DownloadAsync(task.chunkHash, task.chunkIndex, false, func (chunk *Chunk, chunkIndex int) {
+				downloader.completionChannel <- ChunkDownloadCompletion { chunk: chunk, chunkIndex: chunkIndex }
+			})
+			task.isDownloading = true
+			downloader.numberOfDownloadingChunks++
+			downloader.numberOfActiveChunks++
+			downloader.lastChunkIndex++
 		}
 	}
 }
-    }
-
-    // Reset the chunk without a hasher -- the downloaded content will be encrypted and/or compressed and the hasher
-    // will be set up before the encryption
-    chunk.Reset(false)
-
-    // Find the chunk by ID first.
-    chunkPath, exist, _, err := downloader.storage.FindChunk(threadIndex, chunkID, false)
-    if err != nil {
-        LOG_ERROR("DOWNLOAD_CHUNK", "Failed to find the chunk %s: %v", chunkID, err)
-        return false
-    }
-
-    if !exist {
-        // No chunk is found.  Have to find it in the fossil pool again.
-        chunkPath, exist, _, err = downloader.storage.FindChunk(threadIndex, chunkID, true)
-        if err != nil {
-            LOG_ERROR("DOWNLOAD_CHUNK", "Failed to find the chunk %s: %v", chunkID, err)
-            return false
-        }
-
-        if !exist {
-            // A chunk is not found.  This is a serious error and hopefully it will never happen.
-            LOG_FATAL("DOWNLOAD_CHUNK", "Chunk %s can't be found", chunkID)
-            return false
-        }
-        LOG_DEBUG("CHUNK_FOSSIL", "Chunk %s has been marked as a fossil", chunkID)
-    }
-
-    err = downloader.storage.DownloadFile(threadIndex, chunkPath, chunk)
-    if err != nil {
-        LOG_ERROR("UPLOAD_FATAL", "Failed to download the chunk %s: %v", chunkID, err)
-        return false
-    }
-
-
-    err = chunk.Decrypt(downloader.config.ChunkKey, task.chunkHash)
-    if err != nil {
-        LOG_ERROR("UPLOAD_CHUNK", "Failed to decrypt the chunk %s: %v", chunkID, err)
-        return false
-    }
-
-    actualChunkID := chunk.GetID()
-    if actualChunkID != chunkID {
-        LOG_FATAL("UPLOAD_CORRUPTED", "The chunk %s has a hash id of %s", chunkID, actualChunkID)
-        return false
-    }
-
-    if len(cachedPath) > 0 {
-        // Save a copy to the local snapshot cache
-        err = downloader.snapshotCache.UploadFile(threadIndex, cachedPath, chunk.GetBytes())
-        if err != nil {
-            LOG_WARN("DOWNLOAD_CACHE", "Failed to add the chunk %s to the snapshot cache: %v", chunkID, err)
-        }
-    }
-
-    downloadedChunkSize := atomic.AddInt64(&downloader.downloadedChunkSize, int64(chunk.GetLength()))
-
-    if (downloader.showStatistics || IsTracing()) && downloader.totalChunkSize > 0 {
-
-        now := time.Now().Unix()
-        if now <= downloader.startTime {
-            now = downloader.startTime + 1
-        }
-        speed := downloadedChunkSize / (now - downloader.startTime)
-        remainingTime := int64(0)
-        if speed > 0 {
-            remainingTime = (downloader.totalChunkSize - downloadedChunkSize) / speed + 1
-        }
-        percentage := float32(downloadedChunkSize * 1000 / downloader.totalChunkSize)
-        LOG_INFO("DOWNLOAD_PROGRESS", "Downloaded chunk %d size %d, %sB/s %s %.1f%%",
-                    task.chunkIndex + 1, chunk.GetLength(),
-                    PrettySize(speed), PrettyTime(remainingTime), percentage / 10)
-    } else {
-        LOG_DEBUG("CHUNK_DOWNLOAD", "Chunk %s has been downloaded", chunkID)
-    }
-
-    downloader.completionChannel <- ChunkDownloadCompletion{ chunk: chunk, chunkIndex:task.chunkIndex }
-    return true
-}

src/duplicacy_chunkmaker.go

@@ -5,10 +5,10 @@
 package duplicacy
 
 import (
-    "io"
 	"crypto/sha256"
-    "encoding/hex"
 	"encoding/binary"
+	"encoding/hex"
+	"io"
 )
 
 // ChunkMaker breaks data into chunks using buzhash.  To save memory, the chunk maker only use a circular buffer
@@ -25,15 +25,20 @@ type ChunkMaker struct {
 	bufferSize  int
 	bufferStart int
 
+	minimumReached bool
+	hashSum uint64
+	chunk *Chunk
+
 	config *Config
 
 	hashOnly      bool
 	hashOnlyChunk *Chunk
+
 }
 
 // CreateChunkMaker creates a chunk maker.  'randomSeed' is used to generate the character-to-integer table needed by
 // buzhash.
-func CreateChunkMaker(config *Config, hashOnly bool) *ChunkMaker {
+func CreateFileChunkMaker(config *Config, hashOnly bool) *ChunkMaker {
 	size := 1
 	for size*2 <= config.AverageChunkSize {
 		size *= 2
@@ -67,6 +72,33 @@ func CreateChunkMaker(config *Config, hashOnly bool) *ChunkMaker {
 	}
 
 	maker.buffer = make([]byte, 2*config.MinimumChunkSize)
+	maker.bufferStart = 0
+	maker.bufferSize = 0
+
+	maker.startNewChunk()
+
+	return maker
+}
+
+// CreateMetaDataChunkMaker creates a chunk maker that always uses the variable-sized chunking algorithm
+func CreateMetaDataChunkMaker(config *Config, chunkSize int) *ChunkMaker {
+
+	size := 1
+	for size*2 <= chunkSize {
+		size *= 2
+	}
+
+	if size != chunkSize {
+		LOG_FATAL("CHUNK_SIZE", "Invalid metadata chunk size: %d is not a power of 2", chunkSize)
+		return nil
+	}
+
+	maker := CreateFileChunkMaker(config, false)
+	maker.hashMask = uint64(chunkSize - 1)
+	maker.maximumChunkSize = chunkSize * 4
+	maker.minimumChunkSize = chunkSize / 4
+	maker.bufferCapacity = 2 * maker.minimumChunkSize
+	maker.buffer = make([]byte, maker.bufferCapacity)
 
 	return maker
 }
@@ -90,62 +122,50 @@ func (maker *ChunkMaker) buzhashUpdate(sum uint64, out byte, in byte, length int
 	return rotateLeftByOne(sum) ^ rotateLeft(maker.randomTable[out], uint(length)) ^ maker.randomTable[in]
 }
 
-// ForEachChunk reads data from 'reader'.  If EOF is encountered, it will call 'nextReader' to ask for next file.  If
-// 'nextReader' returns false, it will process remaining data in the buffer and then quit.  When a chunk is identified,
-// it will call 'endOfChunk' to return the chunk size and a boolean flag indicating if it is the last chunk.
-func (maker *ChunkMaker) ForEachChunk(reader io.Reader, endOfChunk func(chunk *Chunk, final bool),
-                                      nextReader func(size int64, hash string)(io.Reader, bool)) {
+func (maker *ChunkMaker) startNewChunk() (chunk *Chunk) {
+	maker.hashSum = 0
+	maker.minimumReached = false
+	if maker.hashOnly {
+		maker.chunk = maker.hashOnlyChunk
+		maker.chunk.Reset(true)
+	} else {
+		maker.chunk = maker.config.GetChunk()
+		maker.chunk.Reset(true)
+	}
+	return
+}
 
-    maker.bufferStart = 0
-    maker.bufferSize = 0
-
-    var minimumReached bool
-    var hashSum uint64
-    var chunk *Chunk
+func (maker *ChunkMaker) AddData(reader io.Reader, sendChunk func(*Chunk)) (int64, string) {
 
+	isEOF := false
 	fileSize := int64(0)
 	fileHasher := maker.config.NewFileHasher()
 
-    // Start a new chunk.
-    startNewChunk := func() {
-        hashSum = 0
-        minimumReached = false
-        if maker.hashOnly {
-            chunk = maker.hashOnlyChunk
-            chunk.Reset(true)
-        } else {
-            chunk = maker.config.GetChunk()
-            chunk.Reset(true)
-        }
-    }
-
 	// Move data from the buffer to the chunk.
 	fill := func(count int) {
+
 		if maker.bufferStart+count < maker.bufferCapacity {
-            chunk.Write(maker.buffer[maker.bufferStart : maker.bufferStart + count])
+			maker.chunk.Write(maker.buffer[maker.bufferStart : maker.bufferStart+count])
 			maker.bufferStart += count
 			maker.bufferSize -= count
 		} else {
-            chunk.Write(maker.buffer[maker.bufferStart :])
-            chunk.Write(maker.buffer[: count - (maker.bufferCapacity - maker.bufferStart)])
+			maker.chunk.Write(maker.buffer[maker.bufferStart:])
+			maker.chunk.Write(maker.buffer[:count-(maker.bufferCapacity-maker.bufferStart)])
 			maker.bufferStart = count - (maker.bufferCapacity - maker.bufferStart)
 			maker.bufferSize -= count
 		}
 	}
 
-    startNewChunk()
-
 	var err error
 
-    isEOF := false
-
 	if maker.minimumChunkSize == maker.maximumChunkSize {
 
-        if maker.bufferCapacity < maker.minimumChunkSize {
-            maker.buffer = make([]byte, maker.minimumChunkSize)
+		if reader == nil {
+			return 0, ""
 		}
 
 		for {
+			maker.startNewChunk()
 			maker.bufferStart = 0
 			for maker.bufferStart < maker.minimumChunkSize && !isEOF {
 				count, err := reader.Read(maker.buffer[maker.bufferStart:maker.minimumChunkSize])
@@ -153,7 +173,7 @@ func (maker *ChunkMaker) ForEachChunk(reader io.Reader, endOfChunk func(chunk *C
 				if err != nil {
 					if err != io.EOF {
 						LOG_ERROR("CHUNK_MAKER", "Failed to read %d bytes: %s", count, err.Error())
-                        return
+						return 0, ""
 					} else {
 						isEOF = true
 					}
@@ -161,26 +181,15 @@ func (maker *ChunkMaker) ForEachChunk(reader io.Reader, endOfChunk func(chunk *C
 				maker.bufferStart += count
 			}
 
+			if maker.bufferStart > 0 {
 				fileHasher.Write(maker.buffer[:maker.bufferStart])
 				fileSize += int64(maker.bufferStart)
-            chunk.Write(maker.buffer[:maker.bufferStart])
+				maker.chunk.Write(maker.buffer[:maker.bufferStart])
+				sendChunk(maker.chunk)
+			}
 
 			if isEOF {
-                var ok bool
-                reader, ok = nextReader(fileSize, hex.EncodeToString(fileHasher.Sum(nil)))
-                if !ok {
-                    endOfChunk(chunk, true)
-                    return
-                } else {
-                    endOfChunk(chunk, false)
-                    startNewChunk()
-                    fileSize = 0
-                    fileHasher = maker.config.NewFileHasher()
-                    isEOF = false
-                }
-            } else {
-                endOfChunk(chunk, false)
-                startNewChunk()
+				return fileSize, hex.EncodeToString(fileHasher.Sum(nil))
 			}
 		}
 
@@ -189,7 +198,7 @@ func (maker *ChunkMaker) ForEachChunk(reader io.Reader, endOfChunk func(chunk *C
 	for {
 
 		// If the buffer still has some space left and EOF is not seen, read more data.
-        for maker.bufferSize < maker.bufferCapacity && !isEOF {
+		for maker.bufferSize < maker.bufferCapacity && !isEOF && reader != nil {
 			start := maker.bufferStart + maker.bufferSize
 			count := maker.bufferCapacity - start
 			if start >= maker.bufferCapacity {
@@ -201,7 +210,7 @@ func (maker *ChunkMaker) ForEachChunk(reader io.Reader, endOfChunk func(chunk *C
 
 			if err != nil && err != io.EOF {
 				LOG_ERROR("CHUNK_MAKER", "Failed to read %d bytes: %s", count, err.Error())
-                return
+				return 0, ""
 			}
 
 			maker.bufferSize += count
@@ -210,55 +219,55 @@ func (maker *ChunkMaker) ForEachChunk(reader io.Reader, endOfChunk func(chunk *C
 
 			// if EOF is seen, try to switch to next file and continue
 			if err == io.EOF {
-                var ok bool
-                reader, ok = nextReader(fileSize, hex.EncodeToString(fileHasher.Sum(nil)))
-                if !ok {
 				isEOF = true
-                } else {
-                    fileSize = 0
-                    fileHasher = maker.config.NewFileHasher()
-                    isEOF = false
-                }
+				break
 			}
 		}
 
 		// No eough data to meet the minimum chunk size requirement, so just return as a chunk.
 		if maker.bufferSize < maker.minimumChunkSize {
+			if reader == nil {
 				fill(maker.bufferSize)
-            endOfChunk(chunk, true)
-            return
+				if maker.chunk.GetLength() > 0 {
+					sendChunk(maker.chunk)
+				}
+				return 0, ""
+			} else if isEOF {
+				return fileSize, hex.EncodeToString(fileHasher.Sum(nil))
+			} else {
+				continue
+			}
 		}
 
-
 		// Minimum chunk size has been reached.  Calculate the buzhash for the minimum size chunk.
-        if (!minimumReached) {
+		if !maker.minimumReached {
 
 			bytes := maker.minimumChunkSize
 
 			if maker.bufferStart+bytes < maker.bufferCapacity {
-                hashSum = maker.buzhashSum(0, maker.buffer[maker.bufferStart : maker.bufferStart + bytes])
+				maker.hashSum = maker.buzhashSum(0, maker.buffer[maker.bufferStart:maker.bufferStart+bytes])
 			} else {
-                hashSum = maker.buzhashSum(0, maker.buffer[maker.bufferStart :])
-                hashSum = maker.buzhashSum(hashSum,
+				maker.hashSum = maker.buzhashSum(0, maker.buffer[maker.bufferStart:])
+				maker.hashSum = maker.buzhashSum(maker.hashSum,
 					maker.buffer[:bytes-(maker.bufferCapacity-maker.bufferStart)])
 			}
 
-            if (hashSum & maker.hashMask) == 0 {
+			if (maker.hashSum & maker.hashMask) == 0 {
 				// This is a minimum size chunk
 				fill(bytes)
-                endOfChunk(chunk, false)
-                startNewChunk()
+				sendChunk(maker.chunk)
+				maker.startNewChunk()
 				continue
 			}
 
-            minimumReached = true
+			maker.minimumReached = true
 		}
 
 		// Now check the buzhash of the data in the buffer, shifting one byte at a time.
 		bytes := maker.bufferSize - maker.minimumChunkSize
-        isEOC := false
-        maxSize := maker.maximumChunkSize - chunk.GetLength()
-        for i := 0; i < maker.bufferSize - maker.minimumChunkSize; i++ {
+		isEOC := false // chunk boundary found
+		maxSize := maker.maximumChunkSize - maker.chunk.GetLength()
+		for i := 0; i < bytes; i++ {
 			out := maker.bufferStart + i
 			if out >= maker.bufferCapacity {
 				out -= maker.bufferCapacity
@@ -268,8 +277,8 @@ func (maker *ChunkMaker) ForEachChunk(reader io.Reader, endOfChunk func(chunk *C
 				in -= maker.bufferCapacity
 			}
 
-            hashSum = maker.buzhashUpdate(hashSum, maker.buffer[out], maker.buffer[in], maker.minimumChunkSize)
-            if (hashSum & maker.hashMask) == 0 || i == maxSize - maker.minimumChunkSize - 1 {
+			maker.hashSum = maker.buzhashUpdate(maker.hashSum, maker.buffer[out], maker.buffer[in], maker.minimumChunkSize)
+			if (maker.hashSum&maker.hashMask) == 0 || i == maxSize-maker.minimumChunkSize-1 {
 				// A chunk is completed.
 				bytes = i + 1 + maker.minimumChunkSize
 				isEOC = true
@@ -278,21 +287,20 @@ func (maker *ChunkMaker) ForEachChunk(reader io.Reader, endOfChunk func(chunk *C
 		}
 
 		fill(bytes)
-
 		if isEOC {
-            if isEOF && maker.bufferSize == 0 {
-                endOfChunk(chunk, true)
-                return
+			sendChunk(maker.chunk)
+			maker.startNewChunk()
+		} else {
+			if reader == nil {
+				fill(maker.minimumChunkSize)
+				sendChunk(maker.chunk)
+				maker.startNewChunk()
+				return 0, ""
 			}
-            endOfChunk(chunk, false)
-            startNewChunk()
-            continue
 		}
 
 		if isEOF {
-            fill(maker.bufferSize)
-            endOfChunk(chunk, true)
-            return
+			return fileSize, hex.EncodeToString(fileHasher.Sum(nil))
 		}
 	}
 }

src/duplicacy_chunkmaker_test.go

@@ -5,16 +5,14 @@
 package duplicacy
 
 import (
-    "testing"
 	"bytes"
 	crypto_rand "crypto/rand"
 	"math/rand"
-    "io"
 	"sort"
+	"testing"
 )
 
-func splitIntoChunks(content []byte, n, averageChunkSize, maxChunkSize, minChunkSize,
-                     bufferCapacity int) ([]string, int) {
+func splitIntoChunks(content []byte, n, averageChunkSize, maxChunkSize, minChunkSize int) ([]string, int) {
 
 	config := CreateConfig()
 
@@ -27,14 +25,12 @@ func splitIntoChunks(content []byte, n, averageChunkSize, maxChunkSize, minChunk
 	config.HashKey = DEFAULT_KEY
 	config.IDKey = DEFAULT_KEY
 
-    maker := CreateChunkMaker(config, false)
+	maker := CreateFileChunkMaker(config, false)
 
 	var chunks []string
 	totalChunkSize := 0
 	totalFileSize := int64(0)
 
-    //LOG_INFO("CHUNK_SPLIT", "bufferCapacity: %d", bufferCapacity)
-
 	buffers := make([]*bytes.Buffer, n)
 	sizes := make([]int, n)
 	sizes[0] = 0
@@ -42,7 +38,7 @@ func splitIntoChunks(content []byte, n, averageChunkSize, maxChunkSize, minChunk
 		same := true
 		for same {
 			same = false
-            sizes[i] = rand.Int() % n
+			sizes[i] = rand.Int() % len(content)
 			for j := 0; j < i; j++ {
 				if sizes[i] == sizes[j] {
 					same = true
@@ -59,24 +55,19 @@ func splitIntoChunks(content []byte, n, averageChunkSize, maxChunkSize, minChunk
 	}
 	buffers[n-1] = bytes.NewBuffer(content[sizes[n-1]:])
 
-    i := 0
-
-    maker.ForEachChunk(buffers[0],
-        func (chunk *Chunk, final bool) {
-            //LOG_INFO("CHUNK_SPLIT", "i: %d, chunk: %s, size: %d", i, chunk.GetHash(), size)
+	chunkFunc := func(chunk *Chunk) {
 		chunks = append(chunks, chunk.GetHash())
 		totalChunkSize += chunk.GetLength()
-        },
-        func (size int64, hash string) (io.Reader, bool) {
-            totalFileSize += size
-            i++
-            if i >= len(buffers) {
-                return nil, false
+		config.PutChunk(chunk)
 	}
-            return buffers[i], true
-        })
 
-    if (totalFileSize != int64(totalChunkSize)) {
+	for _, buffer := range buffers {
+		fileSize, _ := maker.AddData(buffer, chunkFunc)
+		totalFileSize += fileSize
+	}
+	maker.AddData(nil, chunkFunc)
+
+	if totalFileSize != int64(totalChunkSize) {
 		LOG_ERROR("CHUNK_SPLIT", "total chunk size: %d, total file size: %d", totalChunkSize, totalFileSize)
 	}
 	return chunks, totalChunkSize
@@ -84,7 +75,6 @@ func splitIntoChunks(content []byte, n, averageChunkSize, maxChunkSize, minChunk
 
 func TestChunkMaker(t *testing.T) {
 
-
 	//sizes := [...] int { 64 }
 	sizes := [...]int{64, 256, 1024, 1024 * 10}
 
@@ -97,36 +87,29 @@ func TestChunkMaker(t *testing.T) {
 			continue
 		}
 
-        chunkArray1, totalSize1 := splitIntoChunks(content, 10, 32, 64, 16, 32)
+		chunkArray1, totalSize1 := splitIntoChunks(content, 10, 32, 64, 16)
 
-        capacities := [...]int { 32, 33, 34, 61, 62, 63, 64, 65, 66, 126, 127, 128, 129, 130,
-                                 255, 256, 257, 511, 512, 513, 1023, 1024, 1025,
-                                 32, 48, 64, 128, 256, 512, 1024, 2048, }
 
-        //capacities := [...]int { 32 }
-
-        for _, capacity := range capacities {
-
-            for _, n := range [...]int { 6, 7, 8, 9, 10 } {
-                chunkArray2, totalSize2 := splitIntoChunks(content, n, 32, 64, 16, capacity)
+		for _, n := range [...]int{6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16} {
+			chunkArray2, totalSize2 := splitIntoChunks(content, n, 32, 64, 16)
 
 			if totalSize1 != totalSize2 {
-                    t.Errorf("[size %d, capacity %d] total size is %d instead of %d",
-                             size, capacity, totalSize2, totalSize1)
+				t.Errorf("[size %d] total size is %d instead of %d",
+					size, totalSize2, totalSize1)
 			}
 
 			if len(chunkArray1) != len(chunkArray2) {
-                    t.Errorf("[size %d, capacity %d] number of chunks is %d instead of %d",
-                             size, capacity, len(chunkArray2), len(chunkArray1))
+				t.Errorf("[size %d] number of chunks is %d instead of %d",
+					size, len(chunkArray2), len(chunkArray1))
 			} else {
 				for i := 0; i < len(chunkArray1); i++ {
 					if chunkArray1[i] != chunkArray2[i] {
-                            t.Errorf("[size %d, capacity %d, chunk %d] chunk is different", size, capacity, i)
-                        }
-                    }
-                }
+						t.Errorf("[size %d, chunk %d] chunk is different", size, i)
 					}
 				}
 			}
 
 		}
+	}
+
+}

src/duplicacy_chunkoperator.go

@@ -0,0 +1,579 @@
+// Copyright (c) Acrosync LLC. All rights reserved.
+// Free for personal use and commercial trial
+// Commercial use requires per-user licenses available from https://duplicacy.com
+
+package duplicacy
+
+import (
+	"io"
+	"sync"
+	"sync/atomic"
+	"time"
+)
+
+// These are operations that ChunkOperator will perform.
+const (
+	ChunkOperationDownload  = 0
+	ChunkOperationUpload    = 1
+	ChunkOperationDelete    = 2
+	ChunkOperationFossilize = 3
+	ChunkOperationResurrect = 4
+	ChunkOperationFind = 5
+)
+
+// ChunkTask is used to pass parameters for different kinds of chunk operations.
+type ChunkTask struct {
+	operation  int    // The type of operation
+	chunkID    string // The chunk id
+	chunkHash  string // The chunk hash
+	chunkIndex int    // The chunk index
+	filePath   string // The path of the chunk file; it may be empty
+
+	isMetadata bool
+	chunk      *Chunk
+
+	completionFunc func(chunk *Chunk, chunkIndex int)
+}
+
+// ChunkOperator is capable of performing multi-threaded operations on chunks.
+type ChunkOperator struct {
+	config *Config               // Associated config
+	storage Storage              // This storage
+	snapshotCache  *FileStorage
+	showStatistics bool
+	threads  int                 // Number of threads
+	taskQueue chan ChunkTask     // Operating goroutines are waiting on this channel for input
+	stopChannel chan bool        // Used to stop all the goroutines
+
+	numberOfActiveTasks int64    // The number of chunks that are being operated on
+
+	fossils []string             // For fossilize operation, the paths of the fossils are stored in this slice
+	collectionLock *sync.Mutex   // The lock for accessing 'fossils'
+
+	startTime int64              // The time it starts downloading
+	totalChunkSize int64         // Total chunk size
+	downloadedChunkSize int64    // Downloaded chunk size
+
+	allowFailures bool           // Whether to fail on download error, or continue
+	NumberOfFailedChunks int64   // The number of chunks that can't be downloaded
+
+	rewriteChunks bool           // Whether to rewrite corrupted chunks when erasure coding is enabled
+
+	UploadCompletionFunc func(chunk *Chunk, chunkIndex int, inCache bool, chunkSize int, uploadSize int)
+}
+
+// CreateChunkOperator creates a new ChunkOperator.
+func CreateChunkOperator(config *Config, storage Storage, snapshotCache *FileStorage, showStatistics bool, rewriteChunks bool, threads int,
+						 allowFailures bool) *ChunkOperator {
+
+	operator := &ChunkOperator{
+		config: config,
+		storage: storage,
+		snapshotCache: snapshotCache,
+		showStatistics: showStatistics,
+		threads: threads,
+
+		taskQueue:   make(chan ChunkTask, threads),
+		stopChannel: make(chan bool),
+
+		collectionLock: &sync.Mutex{},
+		startTime: time.Now().Unix(),
+		allowFailures: allowFailures,
+		rewriteChunks: rewriteChunks,
+	}
+
+	// Start the operator goroutines
+	for i := 0; i < operator.threads; i++ {
+		go func(threadIndex int) {
+			defer CatchLogException()
+			for {
+				select {
+				case task := <-operator.taskQueue:
+					operator.Run(threadIndex, task)
+				case <-operator.stopChannel:
+					return
+				}
+			}
+		}(i)
+	}
+
+	return operator
+}
+
+func (operator *ChunkOperator) Stop() {
+	if atomic.LoadInt64(&operator.numberOfActiveTasks) < 0 {
+		return
+	}
+
+	for atomic.LoadInt64(&operator.numberOfActiveTasks) > 0 {
+		time.Sleep(100 * time.Millisecond)
+	}
+	for i := 0; i < operator.threads; i++ {
+		operator.stopChannel <- false
+	}
+
+	// Assign -1 to numberOfActiveTasks so Stop() can be called multiple times
+	atomic.AddInt64(&operator.numberOfActiveTasks, int64(-1))
+}
+
+func (operator *ChunkOperator) WaitForCompletion() {
+
+	for atomic.LoadInt64(&operator.numberOfActiveTasks) > 0 {
+		time.Sleep(100 * time.Millisecond)
+	}
+}
+
+func (operator *ChunkOperator) AddTask(operation int, chunkID string, chunkHash string, filePath string, chunkIndex int, chunk *Chunk, isMetadata bool, completionFunc func(*Chunk, int))  {
+
+	task := ChunkTask {
+		operation:  operation,
+		chunkID:    chunkID,
+		chunkHash:  chunkHash,
+		chunkIndex: chunkIndex,
+		filePath:   filePath,
+		chunk:      chunk,
+		isMetadata: isMetadata,
+		completionFunc: completionFunc,
+	}
+
+	operator.taskQueue <- task
+	atomic.AddInt64(&operator.numberOfActiveTasks, int64(1))
+
+	return
+}
+
+func (operator *ChunkOperator) Download(chunkHash string, chunkIndex int, isMetadata bool) *Chunk {
+	chunkID := operator.config.GetChunkIDFromHash(chunkHash)
+	completionChannel := make(chan *Chunk)
+	completionFunc := func(chunk *Chunk, chunkIndex int) {
+		completionChannel <- chunk
+	}
+	operator.AddTask(ChunkOperationDownload, chunkID, chunkHash, "", chunkIndex, nil, isMetadata, completionFunc)
+	return <- completionChannel
+}
+
+func (operator *ChunkOperator) DownloadAsync(chunkHash string, chunkIndex int, isMetadata bool, completionFunc func(*Chunk, int)) {
+	chunkID := operator.config.GetChunkIDFromHash(chunkHash)
+	operator.AddTask(ChunkOperationDownload, chunkID, chunkHash, "", chunkIndex, nil, isMetadata, completionFunc)
+}
+
+func (operator *ChunkOperator) Upload(chunk *Chunk, chunkIndex int, isMetadata bool) {
+	chunkHash := chunk.GetHash()
+	chunkID := operator.config.GetChunkIDFromHash(chunkHash)
+	operator.AddTask(ChunkOperationUpload, chunkID, chunkHash, "", chunkIndex, chunk, isMetadata, nil)
+}
+
+func (operator *ChunkOperator) Delete(chunkID string, filePath string) {
+	operator.AddTask(ChunkOperationDelete, chunkID, "", filePath, 0, nil, false, nil)
+}
+
+func (operator *ChunkOperator) Fossilize(chunkID string, filePath string) {
+	operator.AddTask(ChunkOperationFossilize, chunkID, "", filePath, 0, nil, false, nil)
+}
+
+func (operator *ChunkOperator) Resurrect(chunkID string, filePath string) {
+	operator.AddTask(ChunkOperationResurrect, chunkID, "", filePath, 0, nil, false, nil)
+}
+
+func (operator *ChunkOperator) Run(threadIndex int, task ChunkTask) {
+	defer func() {
+		atomic.AddInt64(&operator.numberOfActiveTasks, int64(-1))
+	}()
+
+	if task.operation == ChunkOperationDownload {
+		operator.DownloadChunk(threadIndex, task)
+		return
+	} else if task.operation == ChunkOperationUpload {
+		operator.UploadChunk(threadIndex, task)
+		return
+	}
+
+	// task.filePath may be empty.  If so, find the chunk first.
+	if task.operation == ChunkOperationDelete || task.operation == ChunkOperationFossilize {
+		if task.filePath == "" {
+			filePath, exist, _, err := operator.storage.FindChunk(threadIndex, task.chunkID, false)
+			if err != nil {
+				LOG_ERROR("CHUNK_FIND", "Failed to locate the path for the chunk %s: %v", task.chunkID, err)
+				return
+			} else if !exist {
+				if task.operation == ChunkOperationDelete {
+					LOG_WARN("CHUNK_FIND", "Chunk %s does not exist in the storage", task.chunkID)
+					return
+				}
+
+				fossilPath, exist, _, _ := operator.storage.FindChunk(threadIndex, task.chunkID, true)
+				if exist {
+					LOG_WARN("CHUNK_FOSSILIZE", "Chunk %s is already a fossil", task.chunkID)
+					operator.collectionLock.Lock()
+					operator.fossils = append(operator.fossils, fossilPath)
+					operator.collectionLock.Unlock()
+				} else {
+					LOG_ERROR("CHUNK_FIND", "Chunk %s does not exist in the storage", task.chunkID)
+				}
+				return
+			}
+			task.filePath = filePath
+		}
+	}
+
+	if task.operation == ChunkOperationFind {
+		_, exist, _, err := operator.storage.FindChunk(threadIndex, task.chunkID, false)
+		if err != nil {
+			LOG_ERROR("CHUNK_FIND", "Failed to locate the path for the chunk %s: %v", task.chunkID, err)
+		} else if !exist {
+			LOG_ERROR("CHUNK_FIND", "Chunk %s does not exist in the storage", task.chunkID)
+		} else {
+			LOG_DEBUG("CHUNK_FIND", "Chunk %s exists in the storage", task.chunkID)
+		}
+	} else if task.operation == ChunkOperationDelete {
+		err := operator.storage.DeleteFile(threadIndex, task.filePath)
+		if err != nil {
+			LOG_WARN("CHUNK_DELETE", "Failed to remove the file %s: %v", task.filePath, err)
+		} else {
+			if task.chunkID != "" {
+				LOG_INFO("CHUNK_DELETE", "The chunk %s has been permanently removed", task.chunkID)
+			} else {
+				LOG_INFO("CHUNK_DELETE", "Deleted file %s from the storage", task.filePath)
+			}
+		}
+	} else if task.operation == ChunkOperationFossilize {
+
+		fossilPath := task.filePath + ".fsl"
+
+		err := operator.storage.MoveFile(threadIndex, task.filePath, fossilPath)
+		if err != nil {
+			if _, exist, _, _ := operator.storage.FindChunk(threadIndex, task.chunkID, true); exist {
+				err := operator.storage.DeleteFile(threadIndex, task.filePath)
+				if err == nil {
+					LOG_TRACE("CHUNK_DELETE", "Deleted chunk file %s as the fossil already exists", task.chunkID)
+				}
+				operator.collectionLock.Lock()
+				operator.fossils = append(operator.fossils, fossilPath)
+				operator.collectionLock.Unlock()
+			} else {
+				LOG_ERROR("CHUNK_DELETE", "Failed to fossilize the chunk %s: %v", task.chunkID, err)
+			}
+		} else {
+			LOG_TRACE("CHUNK_FOSSILIZE", "The chunk %s has been marked as a fossil", task.chunkID)
+			operator.collectionLock.Lock()
+			operator.fossils = append(operator.fossils, fossilPath)
+			operator.collectionLock.Unlock()
+		}
+	} else if task.operation == ChunkOperationResurrect {
+		chunkPath, exist, _, err := operator.storage.FindChunk(threadIndex, task.chunkID, false)
+		if err != nil {
+			LOG_ERROR("CHUNK_FIND", "Failed to locate the path for the chunk %s: %v", task.chunkID, err)
+		}
+
+		if exist {
+			operator.storage.DeleteFile(threadIndex, task.filePath)
+			LOG_INFO("FOSSIL_RESURRECT", "The chunk %s already exists", task.chunkID)
+		} else {
+			err := operator.storage.MoveFile(threadIndex, task.filePath, chunkPath)
+			if err != nil {
+				LOG_ERROR("FOSSIL_RESURRECT", "Failed to resurrect the chunk %s from the fossil %s: %v",
+					task.chunkID, task.filePath, err)
+			} else {
+				LOG_INFO("FOSSIL_RESURRECT", "The chunk %s has been resurrected", task.filePath)
+			}
+		}
+	}
+}
+
+// Download downloads a chunk from the storage.
+func (operator *ChunkOperator) DownloadChunk(threadIndex int, task ChunkTask) {
+
+	cachedPath := ""
+	chunk := operator.config.GetChunk()
+	chunk.isMetadata = task.isMetadata
+	chunkID := task.chunkID
+
+	defer func() {
+		if chunk != nil {
+			operator.config.PutChunk(chunk)
+		}
+	} ()
+
+	if task.isMetadata && operator.snapshotCache != nil {
+
+		var exist bool
+		var err error
+
+		// Reset the chunk with a hasher -- we're reading from the cache where chunk are not encrypted or compressed
+		chunk.Reset(true)
+
+		cachedPath, exist, _, err = operator.snapshotCache.FindChunk(threadIndex, chunkID, false)
+		if err != nil {
+			LOG_WARN("DOWNLOAD_CACHE", "Failed to find the cache path for the chunk %s: %v", chunkID, err)
+		} else if exist {
+			err = operator.snapshotCache.DownloadFile(0, cachedPath, chunk)
+			if err != nil {
+				LOG_WARN("DOWNLOAD_CACHE", "Failed to load the chunk %s from the snapshot cache: %v", chunkID, err)
+			} else {
+				actualChunkID := chunk.GetID()
+				if actualChunkID != chunkID {
+					LOG_WARN("DOWNLOAD_CACHE_CORRUPTED",
+						"The chunk %s load from the snapshot cache has a hash id of %s", chunkID, actualChunkID)
+				} else {
+					LOG_DEBUG("CHUNK_CACHE", "Chunk %s has been loaded from the snapshot cache", chunkID)
+
+					task.completionFunc(chunk, task.chunkIndex)
+					chunk = nil
+					return
+				}
+			}
+		}
+	}
+
+	// Reset the chunk without a hasher -- the downloaded content will be encrypted and/or compressed and the hasher
+	// will be set up before the encryption
+	chunk.Reset(false)
+	chunk.isMetadata = task.isMetadata
+
+	// If failures are allowed, complete the task properly
+	completeFailedChunk := func() {
+
+		atomic.AddInt64(&operator.NumberOfFailedChunks, 1)
+		if operator.allowFailures {
+			chunk.isBroken = true
+			task.completionFunc(chunk, task.chunkIndex)
+		}
+	}
+
+	chunkPath := ""
+	fossilPath := ""
+	filePath := ""
+
+	const MaxDownloadAttempts = 3
+	for downloadAttempt := 0; ; downloadAttempt++ {
+
+		exist := false
+		var err error
+
+		// Find the chunk by ID first.
+		chunkPath, exist, _, err = operator.storage.FindChunk(threadIndex, chunkID, false)
+		if err != nil {
+			completeFailedChunk()
+			LOG_WERROR(operator.allowFailures, "DOWNLOAD_CHUNK", "Failed to find the chunk %s: %v", chunkID, err)
+			return
+		}
+
+		if exist {
+			filePath = chunkPath
+		} else {
+			// No chunk is found.  Have to find it in the fossil pool again.
+			fossilPath, exist, _, err = operator.storage.FindChunk(threadIndex, chunkID, true)
+			if err != nil {
+				completeFailedChunk()
+				LOG_WERROR(operator.allowFailures, "DOWNLOAD_CHUNK", "Failed to find the chunk %s: %v", chunkID, err)
+				return
+			}
+
+			if !exist {
+
+				retry := false
+
+				// Retry for Hubic or WebDAV as it may return 404 even when the chunk exists
+				if _, ok := operator.storage.(*HubicStorage); ok {
+					retry = true
+				}
+
+				if _, ok := operator.storage.(*WebDAVStorage); ok {
+					retry = true
+				}
+
+				if retry && downloadAttempt < MaxDownloadAttempts {
+					LOG_WARN("DOWNLOAD_RETRY", "Failed to find the chunk %s; retrying", chunkID)
+					continue
+				}
+
+				// A chunk is not found.  This is a serious error and hopefully it will never happen.
+				completeFailedChunk()
+				if err != nil {
+					LOG_WERROR(operator.allowFailures, "DOWNLOAD_CHUNK", "Chunk %s can't be found: %v", chunkID, err)
+				} else {
+					LOG_WERROR(operator.allowFailures, "DOWNLOAD_CHUNK", "Chunk %s can't be found", chunkID)
+				}
+				return
+			}
+
+			filePath = fossilPath
+			LOG_WARN("DOWNLOAD_FOSSIL", "Chunk %s is a fossil", chunkID)
+		}
+
+		err = operator.storage.DownloadFile(threadIndex, filePath, chunk)
+		if err != nil {
+			_, isHubic := operator.storage.(*HubicStorage)
+			// Retry on EOF or if it is a Hubic backend as it may return 404 even when the chunk exists
+			if (err == io.ErrUnexpectedEOF || isHubic) && downloadAttempt < MaxDownloadAttempts {
+				LOG_WARN("DOWNLOAD_RETRY", "Failed to download the chunk %s: %v; retrying", chunkID, err)
+				chunk.Reset(false)
+				chunk.isMetadata = task.isMetadata
+				continue
+			} else {
+				completeFailedChunk()
+				LOG_WERROR(operator.allowFailures, "DOWNLOAD_CHUNK", "Failed to download the chunk %s: %v", chunkID, err)
+				return
+			}
+		}
+
+		rewriteNeeded := false
+		err, rewriteNeeded = chunk.Decrypt(operator.config.ChunkKey, task.chunkHash)
+		if err != nil {
+			if downloadAttempt < MaxDownloadAttempts {
+				LOG_WARN("DOWNLOAD_RETRY", "Failed to decrypt the chunk %s: %v; retrying", chunkID, err)
+				chunk.Reset(false)
+				chunk.isMetadata = task.isMetadata
+				continue
+			} else {
+				completeFailedChunk()
+				LOG_WERROR(operator.allowFailures, "DOWNLOAD_DECRYPT", "Failed to decrypt the chunk %s: %v", chunkID, err)
+				return
+			}
+		}
+
+		actualChunkID := chunk.GetID()
+		if actualChunkID != chunkID {
+			if downloadAttempt < MaxDownloadAttempts {
+				LOG_WARN("DOWNLOAD_RETRY", "The chunk %s has a hash id of %s; retrying", chunkID, actualChunkID)
+				chunk.Reset(false)
+				chunk.isMetadata = task.isMetadata
+				continue
+			} else {
+				completeFailedChunk()
+				LOG_WERROR(operator.allowFailures, "DOWNLOAD_CORRUPTED", "The chunk %s has a hash id of %s", chunkID, actualChunkID)
+				return
+			}
+		}
+
+		if rewriteNeeded && operator.rewriteChunks {
+
+			if filePath != fossilPath {
+				fossilPath = filePath + ".fsl"
+				err := operator.storage.MoveFile(threadIndex, chunkPath, fossilPath)
+				if err != nil {
+					LOG_WARN("CHUNK_REWRITE", "Failed to fossilize the chunk %s: %v", task.chunkID, err)
+				} else {
+					LOG_TRACE("CHUNK_REWRITE", "The existing chunk %s has been marked as a fossil for rewrite", task.chunkID)
+					operator.collectionLock.Lock()
+					operator.fossils = append(operator.fossils, fossilPath)
+					operator.collectionLock.Unlock()
+				}
+			}
+
+			newChunk := operator.config.GetChunk()
+			newChunk.Reset(true)
+			newChunk.Write(chunk.GetBytes())
+			// Encrypt the chunk only after we know that it must be uploaded.
+			err = newChunk.Encrypt(operator.config.ChunkKey, chunk.GetHash(), task.isMetadata)
+			if err == nil {
+				// Re-upload the chunk
+				err = operator.storage.UploadFile(threadIndex, chunkPath, newChunk.GetBytes())
+				if err != nil {
+					LOG_WARN("CHUNK_REWRITE", "Failed to re-upload the chunk %s: %v", chunkID, err)
+				} else {
+					LOG_INFO("CHUNK_REWRITE", "The chunk %s has been re-uploaded", chunkID)
+				}
+			}
+			operator.config.PutChunk(newChunk)
+		}
+
+		break
+	}
+
+	if chunk.isMetadata && len(cachedPath) > 0 {
+		// Save a copy to the local snapshot cache
+		err := operator.snapshotCache.UploadFile(threadIndex, cachedPath, chunk.GetBytes())
+		if err != nil {
+			LOG_WARN("DOWNLOAD_CACHE", "Failed to add the chunk %s to the snapshot cache: %v", chunkID, err)
+		}
+	}
+
+	downloadedChunkSize := atomic.AddInt64(&operator.downloadedChunkSize, int64(chunk.GetLength()))
+
+	if (operator.showStatistics || IsTracing()) && operator.totalChunkSize > 0 {
+
+		now := time.Now().Unix()
+		if now <= operator.startTime {
+			now = operator.startTime + 1
+		}
+		speed := downloadedChunkSize / (now - operator.startTime)
+		remainingTime := int64(0)
+		if speed > 0 {
+			remainingTime = (operator.totalChunkSize-downloadedChunkSize)/speed + 1
+		}
+		percentage := float32(downloadedChunkSize * 1000 / operator.totalChunkSize)
+		LOG_INFO("DOWNLOAD_PROGRESS", "Downloaded chunk %d size %d, %sB/s %s %.1f%%",
+			task.chunkIndex+1, chunk.GetLength(),
+			PrettySize(speed), PrettyTime(remainingTime), percentage/10)
+	} else {
+		LOG_DEBUG("CHUNK_DOWNLOAD", "Chunk %s has been downloaded", chunkID)
+	}
+
+	task.completionFunc(chunk, task.chunkIndex)
+	chunk = nil
+	return
+}
+
+// UploadChunk is called by the task goroutines to perform the actual uploading
+func (operator *ChunkOperator) UploadChunk(threadIndex int, task ChunkTask) bool {
+
+	chunk := task.chunk
+	chunkID := task.chunkID
+	chunkSize := chunk.GetLength()
+
+	// For a snapshot chunk, verify that its chunk id is correct
+	if task.isMetadata {
+		chunk.VerifyID()
+	}
+
+	if task.isMetadata && operator.snapshotCache != nil && operator.storage.IsCacheNeeded() {
+		// Save a copy to the local snapshot.
+		chunkPath, exist, _, err := operator.snapshotCache.FindChunk(threadIndex, chunkID, false)
+		if err != nil {
+			LOG_WARN("UPLOAD_CACHE", "Failed to find the cache path for the chunk %s: %v", chunkID, err)
+		} else if exist {
+			LOG_DEBUG("CHUNK_CACHE", "Chunk %s already exists in the snapshot cache", chunkID)
+		} else if err = operator.snapshotCache.UploadFile(threadIndex, chunkPath, chunk.GetBytes()); err != nil {
+			LOG_WARN("UPLOAD_CACHE", "Failed to save the chunk %s to the snapshot cache: %v", chunkID, err)
+		} else {
+			LOG_DEBUG("CHUNK_CACHE", "Chunk %s has been saved to the snapshot cache", chunkID)
+		}
+	}
+
+	// This returns the path the chunk file should be at.
+	chunkPath, exist, _, err := operator.storage.FindChunk(threadIndex, chunkID, false)
+	if err != nil {
+		LOG_ERROR("UPLOAD_CHUNK", "Failed to find the path for the chunk %s: %v", chunkID, err)
+		return false
+	}
+
+	if exist {
+		// Chunk deduplication by name in effect here.
+		LOG_DEBUG("CHUNK_DUPLICATE", "Chunk %s already exists", chunkID)
+
+		operator.UploadCompletionFunc(chunk, task.chunkIndex, false, chunkSize, 0)
+		return false
+	}
+
+	// Encrypt the chunk only after we know that it must be uploaded.
+	err = chunk.Encrypt(operator.config.ChunkKey, chunk.GetHash(), task.isMetadata)
+	if err != nil {
+		LOG_ERROR("UPLOAD_CHUNK", "Failed to encrypt the chunk %s: %v", chunkID, err)
+		return false
+	}
+
+	if !operator.config.dryRun {
+		err = operator.storage.UploadFile(threadIndex, chunkPath, chunk.GetBytes())
+		if err != nil {
+			LOG_ERROR("UPLOAD_CHUNK", "Failed to upload the chunk %s: %v", chunkID, err)
+			return false
+		}
+		LOG_DEBUG("CHUNK_UPLOAD", "Chunk %s has been uploaded", chunkID)
+	} else {
+		LOG_DEBUG("CHUNK_UPLOAD", "Uploading was skipped for chunk %s", chunkID)
+	}
+
+	operator.UploadCompletionFunc(chunk, task.chunkIndex, false, chunkSize, chunk.GetLength())
+	return true
+}

src/duplicacy_chunkoperator_test.go

@@ -0,0 +1,118 @@
+// Copyright (c) Acrosync LLC. All rights reserved.
+// Free for personal use and commercial trial
+// Commercial use requires per-user licenses available from https://duplicacy.com
+
+package duplicacy
+
+import (
+	"os"
+	"path"
+	"runtime/debug"
+	"testing"
+	"time"
+
+	crypto_rand "crypto/rand"
+	"math/rand"
+)
+
+func TestChunkOperator(t *testing.T) {
+
+	rand.Seed(time.Now().UnixNano())
+	setTestingT(t)
+	SetLoggingLevel(DEBUG)
+
+	defer func() {
+		if r := recover(); r != nil {
+			switch e := r.(type) {
+			case Exception:
+				t.Errorf("%s %s", e.LogID, e.Message)
+				debug.PrintStack()
+			default:
+				t.Errorf("%v", e)
+				debug.PrintStack()
+			}
+		}
+	}()
+
+	testDir := path.Join(os.TempDir(), "duplicacy_test", "storage_test")
+	os.RemoveAll(testDir)
+	os.MkdirAll(testDir, 0700)
+
+	t.Logf("storage: %s", *testStorageName)
+
+	storage, err := loadStorage(testDir, 1)
+	if err != nil {
+		t.Errorf("Failed to create storage: %v", err)
+		return
+	}
+	storage.EnableTestMode()
+	storage.SetRateLimits(*testRateLimit, *testRateLimit)
+
+	for _, dir := range []string{"chunks", "snapshots"} {
+		err = storage.CreateDirectory(0, dir)
+		if err != nil {
+			t.Errorf("Failed to create directory %s: %v", dir, err)
+			return
+		}
+	}
+
+	numberOfChunks := 100
+	maxChunkSize := 64 * 1024
+
+	if *testQuickMode {
+		numberOfChunks = 10
+	}
+
+	var chunks []*Chunk
+
+	config := CreateConfig()
+	config.MinimumChunkSize = 100
+	config.chunkPool = make(chan *Chunk, numberOfChunks*2)
+	totalFileSize := 0
+
+	for i := 0; i < numberOfChunks; i++ {
+		content := make([]byte, rand.Int()%maxChunkSize+1)
+		_, err = crypto_rand.Read(content)
+		if err != nil {
+			t.Errorf("Error generating random content: %v", err)
+			return
+		}
+
+		chunk := CreateChunk(config, true)
+		chunk.Reset(true)
+		chunk.Write(content)
+		chunks = append(chunks, chunk)
+
+		t.Logf("Chunk: %s, size: %d", chunk.GetID(), chunk.GetLength())
+		totalFileSize += chunk.GetLength()
+	}
+
+	chunkOperator := CreateChunkOperator(config, storage, nil, false, false, *testThreads, false)
+	chunkOperator.UploadCompletionFunc = func(chunk *Chunk, chunkIndex int, skipped bool, chunkSize int, uploadSize int) {
+		t.Logf("Chunk %s size %d (%d/%d) uploaded", chunk.GetID(), chunkSize, chunkIndex, len(chunks))
+	}
+
+	for i, chunk := range chunks {
+		chunkOperator.Upload(chunk, i, false)
+	}
+
+	chunkOperator.WaitForCompletion()
+
+	for i, chunk := range chunks {
+		downloaded := chunkOperator.Download(chunk.GetHash(), i, false)
+		if downloaded.GetID() != chunk.GetID() {
+			t.Errorf("Uploaded: %s, downloaded: %s", chunk.GetID(), downloaded.GetID())
+		}
+	}
+
+	chunkOperator.Stop()
+
+	for _, file := range listChunks(storage) {
+		err = storage.DeleteFile(0, "chunks/"+file)
+		if err != nil {
+			t.Errorf("Failed to delete the file %s: %v", file, err)
+			return
+		}
+	}
+
+}

src/duplicacy_chunkuploader.go

@@ -1,147 +0,0 @@
-// Copyright (c) Acrosync LLC. All rights reserved.
-// Free for personal use and commercial trial
-// Commercial use requires per-user licenses available from https://duplicacy.com
-
-package duplicacy
-
-import (
-    "sync/atomic"
-    "time"
-)
-
-// ChunkUploadTask represents a chunk to be uploaded.
-type ChunkUploadTask struct {
-    chunk * Chunk
-    chunkIndex int
-}
-
-// ChunkUploader uploads chunks to the storage using one or more uploading goroutines.  Chunks are added
-// by the call to StartChunk(), and then passed to the uploading goroutines.  The completion function is
-// called when the downloading is completed.  Note that ChunkUploader does not release chunks to the
-// chunk pool; instead
-type ChunkUploader struct {
-    config *Config                    // Associated config
-    storage Storage                   // Download from this storage
-    snapshotCache *FileStorage        // Used as cache if not nil; usually for uploading snapshot chunks
-    threads int                       // Number of uploading goroutines
-    taskQueue chan ChunkUploadTask    // Uploading goroutines are listening on this channel for upload jobs
-    stopChannel chan bool             // Used to terminate uploading goroutines
-
-    numberOfUploadingTasks int32      // The number of uploading tasks
-
-    // Uploading goroutines call this function after having downloaded chunks
-    completionFunc func(chunk *Chunk, chunkIndex int, skipped bool, chunkSize int, uploadSize int)
-}
-
-// CreateChunkUploader creates a chunk uploader.
-func CreateChunkUploader(config *Config, storage Storage, snapshotCache *FileStorage, threads int,
-                         completionFunc func(chunk *Chunk, chunkIndex int, skipped bool, chunkSize int, uploadSize int)) *ChunkUploader {
-    uploader := &ChunkUploader {
-        config: config,
-        storage: storage,
-        snapshotCache: snapshotCache,
-        threads: threads,
-        taskQueue: make(chan ChunkUploadTask, 1),
-        stopChannel: make(chan bool),
-        completionFunc: completionFunc,
-    }
-
-    return uploader
-}
-
-// Starts starts uploading goroutines.
-func (uploader *ChunkUploader) Start() {
-    for i := 0; i < uploader.threads; i++ {
-        go func(threadIndex int) {
-            defer CatchLogException()
-            for {
-                select {
-                case task := <- uploader.taskQueue:
-                    uploader.Upload(threadIndex, task)
-                case <- uploader.stopChannel:
-                    return
-                }
-            }
-        } (i)
-    }
-}
-
-// StartChunk sends a chunk to be uploaded to  a waiting uploading goroutine.  It may block if all uploading goroutines are busy.
-func (uploader *ChunkUploader) StartChunk(chunk *Chunk, chunkIndex int) {
-    atomic.AddInt32(&uploader.numberOfUploadingTasks, 1)
-    uploader.taskQueue <- ChunkUploadTask {
-        chunk: chunk,
-        chunkIndex: chunkIndex,
-    }
-}
-
-// Stop stops all uploading goroutines.
-func (uploader *ChunkUploader) Stop() {
-    for atomic.LoadInt32(&uploader.numberOfUploadingTasks) > 0 {
-        time.Sleep(100 * time.Millisecond)
-    }
-    for i := 0; i < uploader.threads; i++ {
-        uploader.stopChannel <- false
-    }
-}
-
-// Upload is called by the uploading goroutines to perform the actual uploading
-func (uploader *ChunkUploader) Upload(threadIndex int, task ChunkUploadTask) bool {
-
-    chunk := task.chunk
-    chunkSize := chunk.GetLength()
-    chunkID := chunk.GetID()
-
-    // For a snapshot chunk, verify that its chunk id is correct
-    if uploader.snapshotCache != nil {
-        chunk.VerifyID()
-    }
-
-    if uploader.snapshotCache != nil && uploader.storage.IsCacheNeeded() {
-        // Save a copy to the local snapshot.
-        chunkPath, exist, _, err := uploader.snapshotCache.FindChunk(threadIndex, chunkID, false)
-        if err != nil {
-            LOG_WARN("UPLOAD_CACHE", "Failed to find the cache path for the chunk %s: %v", chunkID, err)
-        } else if exist {
-            LOG_DEBUG("CHUNK_CACHE", "Chunk %s already exists in the snapshot cache", chunkID)
-        } else if err = uploader.snapshotCache.UploadFile(threadIndex, chunkPath, chunk.GetBytes()); err != nil {
-            LOG_WARN("UPLOAD_CACHE", "Failed to save the chunk %s to the snapshot cache: %v", chunkID, err)
-        } else {
-            LOG_DEBUG("CHUNK_CACHE", "Chunk %s has been saved to the snapshot cache", chunkID)
-        }
-    }
-
-    // This returns the path the chunk file should be at.
-    chunkPath, exist, _, err := uploader.storage.FindChunk(threadIndex, chunkID, false)
-    if err != nil {
-        LOG_ERROR("UPLOAD_CHUNK", "Failed to find the path for the chunk %s: %v", chunkID, err)
-        return false
-    }
-
-    if exist {
-        // Chunk deduplication by name in effect here.
-        LOG_DEBUG("CHUNK_DUPLICATE", "Chunk %s already exists", chunkID)
-
-        uploader.completionFunc(chunk, task.chunkIndex, false, chunkSize, 0)
-        atomic.AddInt32(&uploader.numberOfUploadingTasks, -1)
-        return false
-    }
-
-    // Encrypt the chunk only after we know that it must be uploaded.
-    err = chunk.Encrypt(uploader.config.ChunkKey, chunk.GetHash())
-    if err != nil {
-        LOG_ERROR("UPLOAD_CHUNK", "Failed to encrypt the chunk %s: %v", chunkID, err)
-        return false
-    }
-
-    err = uploader.storage.UploadFile(threadIndex, chunkPath, chunk.GetBytes())
-    if err != nil {
-        LOG_ERROR("UPLOAD_CHUNK", "Failed to upload the chunk %s: %v", chunkID, err)
-        return false
-    }
-
-    LOG_DEBUG("CHUNK_UPLOAD", "Chunk %s has been uploaded", chunkID)
-    uploader.completionFunc(chunk, task.chunkIndex, false, chunkSize, chunk.GetLength())
-    atomic.AddInt32(&uploader.numberOfUploadingTasks, -1)
-    return true
-}

src/duplicacy_chunkuploader_test.go

@@ -1,130 +0,0 @@
-// Copyright (c) Acrosync LLC. All rights reserved.
-// Free for personal use and commercial trial
-// Commercial use requires per-user licenses available from https://duplicacy.com
-
-package duplicacy
-
-import (
-    "os"
-    "time"
-    "path"
-    "testing"
-    "runtime/debug"
-
-    crypto_rand "crypto/rand"
-    "math/rand"
-)
-
-func TestUploaderAndDownloader(t *testing.T) {
-
-    rand.Seed(time.Now().UnixNano())
-    setTestingT(t)
-    SetLoggingLevel(INFO)
-
-    defer func() {
-        if r := recover(); r != nil {
-            switch e := r.(type) {
-            case Exception:
-                t.Errorf("%s %s", e.LogID, e.Message)
-                debug.PrintStack()
-            default:
-                t.Errorf("%v", e)
-                debug.PrintStack()
-            }
-        }
-    } ()
-
-    testDir := path.Join(os.TempDir(), "duplicacy_test", "storage_test")
-    os.RemoveAll(testDir)
-    os.MkdirAll(testDir, 0700)
-
-    t.Logf("storage: %s", testStorageName)
-
-    storage, err := loadStorage(testDir, 1)
-    if err != nil {
-        t.Errorf("Failed to create storage: %v", err)
-        return
-    }
-    storage.EnableTestMode()
-    storage.SetRateLimits(testRateLimit, testRateLimit)
-
-    for _, dir := range []string { "chunks", "snapshots" }  {
-        err = storage.CreateDirectory(0, dir)
-        if err != nil {
-            t.Errorf("Failed to create directory %s: %v", dir, err)
-            return
-        }
-    }
-
-
-    numberOfChunks := 100
-    maxChunkSize := 64 * 1024
-
-    if testQuickMode {
-        numberOfChunks = 10
-    }
-
-    var chunks []*Chunk
-
-    config := CreateConfig()
-    config.MinimumChunkSize = 100
-    config.chunkPool = make(chan *Chunk, numberOfChunks * 2)
-    totalFileSize := 0
-
-    for i := 0; i < numberOfChunks; i++ {
-        content := make([]byte, rand.Int() % maxChunkSize + 1)
-        _, err = crypto_rand.Read(content)
-        if err != nil {
-            t.Errorf("Error generating random content: %v", err)
-            return
-        }
-
-        chunk := CreateChunk(config, true)
-        chunk.Reset(true)
-        chunk.Write(content)
-        chunks = append(chunks, chunk)
-
-        t.Logf("Chunk: %s, size: %d", chunk.GetID(), chunk.GetLength())
-        totalFileSize += chunk.GetLength()
-    }
-
-    completionFunc := func(chunk *Chunk, chunkIndex int, skipped bool, chunkSize int, uploadSize int) {
-        t.Logf("Chunk %s size %d (%d/%d) uploaded", chunk.GetID(), chunkSize, chunkIndex, len(chunks))
-    }
-
-    chunkUploader := CreateChunkUploader(config, storage, nil, testThreads, nil)
-    chunkUploader.completionFunc = completionFunc
-    chunkUploader.Start()
-
-    for i, chunk := range chunks {
-        chunkUploader.StartChunk(chunk, i)
-    }
-
-    chunkUploader.Stop()
-
-
-    chunkDownloader := CreateChunkDownloader(config, storage, nil, true, testThreads)
-    chunkDownloader.totalChunkSize = int64(totalFileSize)
-
-    for _, chunk := range chunks {
-        chunkDownloader.AddChunk(chunk.GetHash())
-    }
-
-    for i, chunk := range chunks {
-        downloaded := chunkDownloader.WaitForChunk(i)
-        if downloaded.GetID() != chunk.GetID() {
-            t.Error("Uploaded: %s, downloaded: %s", chunk.GetID(), downloaded.GetID())
-        }
-    }
-
-    chunkDownloader.Stop()
-
-    for _, file := range listChunks(storage) {
-        err = storage.DeleteFile(0, "chunks/" + file)
-        if err != nil {
-            t.Errorf("Failed to delete the file %s: %v", file, err)
-            return
-        }
-    }
-
-}

src/duplicacy_config.go

@@ -5,18 +5,25 @@
 package duplicacy
 
 import (
-    "encoding/json"
 	"bytes"
-    "os"
+	"crypto/hmac"
+	"crypto/rand"
+	"crypto/sha256"
+	"crypto/rsa"
+	"crypto/x509"
+	"encoding/binary"
+	"encoding/hex"
+	"encoding/json"
+	"encoding/pem"
 	"fmt"
 	"hash"
+	"os"
+	"strings"
 	"runtime"
 	"runtime/debug"
 	"sync/atomic"
-    "crypto/rand"
-    "crypto/hmac"
-    "crypto/sha256"
-    "encoding/hex"
+	"io/ioutil"
+	"reflect"
 
 	blake2 "github.com/minio/blake2b-simd"
 )
@@ -28,6 +35,28 @@ var DEFAULT_KEY = []byte("duplicacy")
 // standard zlib levels of -1 to 9.
 var DEFAULT_COMPRESSION_LEVEL = 100
 
+// zstd compression levels starting from 200
+var ZSTD_COMPRESSION_LEVEL_FASTEST = 200
+var ZSTD_COMPRESSION_LEVEL_DEFAULT = 201
+var ZSTD_COMPRESSION_LEVEL_BETTER = 202
+var ZSTD_COMPRESSION_LEVEL_BEST = 203
+
+var ZSTD_COMPRESSION_LEVELS = map[string]int {
+    "fastest": ZSTD_COMPRESSION_LEVEL_FASTEST,
+	"default": ZSTD_COMPRESSION_LEVEL_DEFAULT,
+	"better":  ZSTD_COMPRESSION_LEVEL_BETTER,
+	"best":    ZSTD_COMPRESSION_LEVEL_BEST,
+}
+
+// The new banner of the config file (to differentiate from the old format where the salt and iterations are fixed)
+var CONFIG_BANNER = "duplicacy\001"
+
+// The length of the salt used in the new format
+var CONFIG_SALT_LENGTH = 32
+
+// The default iterations for key derivation
+var CONFIG_DEFAULT_ITERATIONS = 16384
+
 type Config struct {
 	CompressionLevel int `json:"compression-level"`
 	AverageChunkSize int `json:"average-chunk-size"`
@@ -36,6 +65,8 @@ type Config struct {
 
 	ChunkSeed []byte `json:"chunk-seed"`
 
+	FixedNesting bool `json:"fixed-nesting"`
+
 	// Use HMAC-SHA256(hashKey, plaintext) as the chunk hash.
 	// Use HMAC-SHA256(idKey, chunk hash) as the file name of the chunk
 	// For chunks, use HMAC-SHA256(chunkKey, chunk hash) as the encryption key
@@ -53,8 +84,17 @@ type Config struct {
 	// for encrypting a non-chunk file
 	FileKey []byte `json:"-"`
 
-    chunkPool chan *Chunk                  `json:"-"`
+	// for erasure coding
+	DataShards int `json:'data-shards'`
+	ParityShards int `json:'parity-shards'`
+
+	// for RSA encryption
+	rsaPrivateKey *rsa.PrivateKey
+	rsaPublicKey *rsa.PublicKey
+
+	chunkPool      chan *Chunk
 	numberOfChunks int32
+	dryRun         bool
 }
 
 // Create an alias to avoid recursive calls on Config.MarshalJSON
@@ -67,10 +107,15 @@ type jsonableConfig struct {
 	IDKey     string `json:"id-key"`
 	ChunkKey  string `json:"chunk-key"`
 	FileKey   string `json:"file-key"`
+	RSAPublicKey string `json:"rsa-public-key"`
 }
 
 func (config *Config) MarshalJSON() ([]byte, error) {
 
+	publicKey := []byte {}
+	if config.rsaPublicKey != nil {
+		publicKey, _ = x509.MarshalPKIXPublicKey(config.rsaPublicKey)
+	}
 	return json.Marshal(&jsonableConfig{
 		aliasedConfig: (*aliasedConfig)(config),
 		ChunkSeed:     hex.EncodeToString(config.ChunkSeed),
@@ -78,6 +123,7 @@ func (config *Config) MarshalJSON() ([] byte, error) {
 		IDKey:         hex.EncodeToString(config.IDKey),
 		ChunkKey:      hex.EncodeToString(config.ChunkKey),
 		FileKey:       hex.EncodeToString(config.FileKey),
+		RSAPublicKey:  hex.EncodeToString(publicKey),
 	})
 }
 
@@ -107,13 +153,25 @@ func (config *Config) UnmarshalJSON(description []byte) (err error) {
 		return fmt.Errorf("Invalid representation of the file key in the config")
 	}
 
+	if publicKey, err := hex.DecodeString(aliased.RSAPublicKey); err != nil {
+		return fmt.Errorf("Invalid hex encoding of the RSA public key in the config")
+	} else if len(publicKey) > 0 {
+		parsedKey, err := x509.ParsePKIXPublicKey(publicKey)
+		if err != nil {
+			return fmt.Errorf("Invalid RSA public key in the config: %v", err)
+		}
+		config.rsaPublicKey = parsedKey.(*rsa.PublicKey)
+		if config.rsaPublicKey == nil {
+			return fmt.Errorf("Unsupported public key type %s in the config", reflect.TypeOf(parsedKey))
+		}
+	}
+
 	return nil
 }
 
-func (config *Config) IsCompatiableWith(otherConfig *Config) bool {
+func (config *Config) IsCompatibleWith(otherConfig *Config) bool {
 
-    return config.CompressionLevel == otherConfig.CompressionLevel &&
-           config.AverageChunkSize == otherConfig.AverageChunkSize &&
+	return config.AverageChunkSize == otherConfig.AverageChunkSize &&
 		config.MaximumChunkSize == otherConfig.MaximumChunkSize &&
 		config.MinimumChunkSize == otherConfig.MinimumChunkSize &&
 		bytes.Equal(config.ChunkSeed, otherConfig.ChunkSeed) &&
@@ -127,16 +185,52 @@ func (config *Config) Print() {
 	LOG_INFO("CONFIG_INFO", "Maximum chunk size: %d", config.MaximumChunkSize)
 	LOG_INFO("CONFIG_INFO", "Minimum chunk size: %d", config.MinimumChunkSize)
 	LOG_INFO("CONFIG_INFO", "Chunk seed: %x", config.ChunkSeed)
+
+	LOG_TRACE("CONFIG_INFO", "Hash key: %x", config.HashKey)
+	LOG_TRACE("CONFIG_INFO", "ID key: %x", config.IDKey)
+
+	if len(config.ChunkKey) > 0 {
+		LOG_TRACE("CONFIG_INFO", "File chunks are encrypted")
+	}
+
+	if len(config.FileKey) > 0 {
+		LOG_TRACE("CONFIG_INFO", "Metadata chunks are encrypted")
+	}
+
+	if config.DataShards != 0 && config.ParityShards != 0 {
+		LOG_TRACE("CONFIG_INFO", "Data shards: %d, parity shards: %d", config.DataShards, config.ParityShards)
+	}
+
+	if config.rsaPublicKey != nil {
+		pkisPublicKey, _ := x509.MarshalPKIXPublicKey(config.rsaPublicKey)
+
+		publicKey := pem.EncodeToMemory(&pem.Block{
+			Type:  "PUBLIC KEY",
+			Bytes: pkisPublicKey,
+		})
+
+		LOG_TRACE("CONFIG_INFO", "RSA public key: %s", publicKey)
+	}
+
+}
+
+func (config *Config) PrintCompressionLevel() {
+	for name, level := range ZSTD_COMPRESSION_LEVELS {
+		if level == config.CompressionLevel {
+			LOG_INFO("COMPRESSION_LEVEL", "Zstd compression is enabled (level: %s)", name)
+		}
+	}
 }
 
 func CreateConfigFromParameters(compressionLevel int, averageChunkSize int, maximumChunkSize int, mininumChunkSize int,
-                  isEncrypted bool, copyFrom *Config) (config *Config) {
+	isEncrypted bool, copyFrom *Config, bitCopy bool) (config *Config) {
 
 	config = &Config{
 		CompressionLevel: compressionLevel,
 		AverageChunkSize: averageChunkSize,
 		MaximumChunkSize: maximumChunkSize,
 		MinimumChunkSize: mininumChunkSize,
+		FixedNesting:     true,
 	}
 
 	if isEncrypted {
@@ -160,7 +254,6 @@ func CreateConfigFromParameters(compressionLevel int, averageChunkSize int, maxi
 	}
 
 	if copyFrom != nil {
-        config.CompressionLevel = copyFrom.CompressionLevel
 
 		config.AverageChunkSize = copyFrom.AverageChunkSize
 		config.MaximumChunkSize = copyFrom.MaximumChunkSize
@@ -168,6 +261,14 @@ func CreateConfigFromParameters(compressionLevel int, averageChunkSize int, maxi
 
 		config.ChunkSeed = copyFrom.ChunkSeed
 		config.HashKey = copyFrom.HashKey
+
+		if bitCopy {
+			config.CompressionLevel = copyFrom.CompressionLevel
+
+			config.IDKey = copyFrom.IDKey
+			config.ChunkKey = copyFrom.ChunkKey
+			config.FileKey = copyFrom.FileKey
+		}
 	}
 
 	config.chunkPool = make(chan *Chunk, runtime.NumCPU()*16)
@@ -214,7 +315,10 @@ func (config *Config) PutChunk(chunk *Chunk){
 }
 
 func (config *Config) NewKeyedHasher(key []byte) hash.Hash {
-    if config.CompressionLevel == DEFAULT_COMPRESSION_LEVEL {
+	// Early versions of Duplicacy used SHA256 as the hash function for chunk IDs at the time when
+	// only zlib compression was supported.  Later SHA256 was replaced by Blake2b and LZ4 was used
+	// for compression (with compression level set to 100).
+	if config.CompressionLevel >= DEFAULT_COMPRESSION_LEVEL {
 		hasher, err := blake2.New(&blake2.Config{Size: 32, Key: key})
 		if err != nil {
 			LOG_ERROR("HASH_KEY", "Invalid hash key: %x", key)
@@ -259,7 +363,7 @@ func (hasher *DummyHasher) BlockSize() int {
 func (config *Config) NewFileHasher() hash.Hash {
 	if SkipFileHash {
 		return &DummyHasher{}
-    } else if config.CompressionLevel == DEFAULT_COMPRESSION_LEVEL {
+	} else if config.CompressionLevel >= DEFAULT_COMPRESSION_LEVEL {
 		hasher, _ := blake2.New(&blake2.Config{Size: 32})
 		return hasher
 	} else {
@@ -315,13 +419,48 @@ func DownloadConfig(storage Storage, password string) (config *Config, isEncrypt
 		return nil, false, err
 	}
 
+	if len(configFile.GetBytes()) < len(ENCRYPTION_BANNER) {
+		return nil, false, fmt.Errorf("The storage has an invalid config file")
+	}
+
+	if string(configFile.GetBytes()[:len(ENCRYPTION_BANNER)-1]) == ENCRYPTION_BANNER[:len(ENCRYPTION_BANNER)-1] && len(password) == 0 {
+		return nil, true, fmt.Errorf("The storage is likely to have been initialized with a password before")
+	}
+
 	var masterKey []byte
 
 	if len(password) > 0 {
-        masterKey = GenerateKeyFromPassword(password)
+
+		if string(configFile.GetBytes()[:len(ENCRYPTION_BANNER)]) == ENCRYPTION_BANNER {
+			// This is the old config format with a static salt and a fixed number of iterations
+			masterKey = GenerateKeyFromPassword(password, DEFAULT_KEY, CONFIG_DEFAULT_ITERATIONS)
+			LOG_TRACE("CONFIG_FORMAT", "Using a static salt and %d iterations for key derivation", CONFIG_DEFAULT_ITERATIONS)
+		} else if string(configFile.GetBytes()[:len(CONFIG_BANNER)]) == CONFIG_BANNER {
+			// This is the new config format with a random salt and a configurable number of iterations
+			encryptedLength := len(configFile.GetBytes()) - CONFIG_SALT_LENGTH - 4
+
+			// Extract the salt and the number of iterations
+			saltStart := configFile.GetBytes()[len(CONFIG_BANNER):]
+			iterations := binary.LittleEndian.Uint32(saltStart[CONFIG_SALT_LENGTH : CONFIG_SALT_LENGTH+4])
+			LOG_TRACE("CONFIG_ITERATIONS", "Using %d iterations for key derivation", iterations)
+			masterKey = GenerateKeyFromPassword(password, saltStart[:CONFIG_SALT_LENGTH], int(iterations))
+
+			// Copy to a temporary buffer to replace the banner and remove the salt and the number of riterations
+			var encrypted bytes.Buffer
+			encrypted.Write([]byte(ENCRYPTION_BANNER))
+			encrypted.Write(saltStart[CONFIG_SALT_LENGTH+4:])
+
+			configFile.Reset(false)
+			configFile.Write(encrypted.Bytes())
+			if len(configFile.GetBytes()) != encryptedLength {
+				LOG_ERROR("CONFIG_DOWNLOAD", "Encrypted config has %d bytes instead of expected %d bytes", len(configFile.GetBytes()), encryptedLength)
+			}
+		} else {
+			return nil, true, fmt.Errorf("The config file has an invalid banner")
+		}
 
 		// Decrypt the config file.  masterKey == nil means no encryption.
-        err = configFile.Decrypt(masterKey, "")
+		err, _ = configFile.Decrypt(masterKey, "")
 		if err != nil {
 			return nil, false, fmt.Errorf("Failed to retrieve the config file: %v", err)
 		}
@@ -330,23 +469,21 @@ func DownloadConfig(storage Storage, password string) (config *Config, isEncrypt
 	config = CreateConfig()
 
 	err = json.Unmarshal(configFile.GetBytes(), config)
-
 	if err != nil {
-        if bytes.Equal(configFile.GetBytes()[:9], []byte("duplicacy")) {
-            return nil, true, fmt.Errorf("The storage is likely to have been initialized with a password before")
-        } else {
 		return nil, false, fmt.Errorf("Failed to parse the config file: %v", err)
 	}
-    }
+
+	storage.SetNestingLevels(config)
 
 	return config, false, nil
 
 }
 
-func UploadConfig(storage Storage, config *Config, password string) (bool) {
+func UploadConfig(storage Storage, config *Config, password string, iterations int) bool {
 
 	// This is the key to encrypt the config file.
 	var masterKey []byte
+	salt := make([]byte, CONFIG_SALT_LENGTH)
 
 	if len(password) > 0 {
 
@@ -355,7 +492,13 @@ func UploadConfig(storage Storage, config *Config, password string) (bool) {
 			return false
 		}
 
-        masterKey = GenerateKeyFromPassword(password)
+		_, err := rand.Read(salt)
+		if err != nil {
+			LOG_ERROR("CONFIG_KEY", "Failed to generate random salt: %v", err)
+			return false
+		}
+
+		masterKey = GenerateKeyFromPassword(password, salt, iterations)
 	}
 
 	description, err := json.MarshalIndent(config, "", "    ")
@@ -371,12 +514,27 @@ func UploadConfig(storage Storage, config *Config, password string) (bool) {
 
 	if len(password) > 0 {
 		// Encrypt the config file with masterKey.  If masterKey is nil then no encryption is performed.
-        err = chunk.Encrypt(masterKey, "")
-
+		err = chunk.Encrypt(masterKey, "", true)
 		if err != nil {
 			LOG_ERROR("CONFIG_CREATE", "Failed to create the config file: %v", err)
 			return false
 		}
+
+		// The new encrypted format for config is CONFIG_BANNER + salt + #iterations + encrypted content
+		encryptedLength := len(chunk.GetBytes()) + CONFIG_SALT_LENGTH + 4
+
+		// Copy to a temporary buffer to replace the banner and add the salt and the number of iterations
+		var encrypted bytes.Buffer
+		encrypted.Write([]byte(CONFIG_BANNER))
+		encrypted.Write(salt)
+		binary.Write(&encrypted, binary.LittleEndian, uint32(iterations))
+		encrypted.Write(chunk.GetBytes()[len(ENCRYPTION_BANNER):])
+
+		chunk.Reset(false)
+		chunk.Write(encrypted.Bytes())
+		if len(chunk.GetBytes()) != encryptedLength {
+			LOG_ERROR("CONFIG_CREATE", "Encrypted config has %d bytes instead of expected %d bytes", len(chunk.GetBytes()), encryptedLength)
+		}
 	}
 
 	err = storage.UploadFile(0, "config", chunk.GetBytes())
@@ -402,8 +560,8 @@ func UploadConfig(storage Storage, config *Config, password string) (bool) {
 // ConfigStorage makes the general storage space available for storing duplicacy format snapshots.  In essence,
 // it simply creates a file named 'config' that stores various parameters as well as a set of keys if encryption
 // is enabled.
-func ConfigStorage(storage Storage, compressionLevel int, averageChunkSize int, maximumChunkSize int,
-                   minimumChunkSize int, password string, copyFrom *Config) bool {
+func ConfigStorage(storage Storage, iterations int, compressionLevel int, averageChunkSize int, maximumChunkSize int,
+	minimumChunkSize int, password string, copyFrom *Config, bitCopy bool, keyFile string, dataShards int, parityShards int) bool {
 
 	exist, _, _, err := storage.GetFileInfo(0, "config")
 	if err != nil {
@@ -416,12 +574,135 @@ func ConfigStorage(storage Storage, compressionLevel int, averageChunkSize int,
 		return false
 	}
 
-
 	config := CreateConfigFromParameters(compressionLevel, averageChunkSize, maximumChunkSize, minimumChunkSize, len(password) > 0,
-                           copyFrom)
+		copyFrom, bitCopy)
 	if config == nil {
 		return false
 	}
 
-    return UploadConfig(storage, config, password)
+	if keyFile != "" {
+		config.loadRSAPublicKey(keyFile)
+	}
+
+	config.DataShards = dataShards
+	config.ParityShards = parityShards
+
+	return UploadConfig(storage, config, password, iterations)
+}
+
+func (config *Config) loadRSAPublicKey(keyFile string) {
+	encodedKey := []byte(keyFile)
+	var err error
+
+	// keyFile may be the actually key, in which case we don't need to read from a file
+	if !strings.Contains(keyFile, "-----BEGIN") {
+		encodedKey, err = ioutil.ReadFile(keyFile)
+		if err != nil {
+			LOG_ERROR("BACKUP_KEY", "Failed to read the public key file: %v", err)
+			return
+		}
+	}
+
+	decodedKey, _ := pem.Decode(encodedKey)
+	if decodedKey == nil {
+		LOG_ERROR("RSA_PUBLIC", "unrecognized public key in %s", keyFile)
+		return
+	}
+	if decodedKey.Type != "PUBLIC KEY" {
+		LOG_ERROR("RSA_PUBLIC", "Unsupported public key type %s in %s", decodedKey.Type, keyFile)
+		return
+	}
+
+	parsedKey, err := x509.ParsePKIXPublicKey(decodedKey.Bytes)
+	if err != nil {
+		LOG_ERROR("RSA_PUBLIC", "Failed to parse the public key in %s: %v", keyFile, err)
+		return
+	}
+
+	key, ok := parsedKey.(*rsa.PublicKey)
+	if !ok {
+		LOG_ERROR("RSA_PUBLIC", "Unsupported public key type %s in %s", reflect.TypeOf(parsedKey), keyFile)
+		return
+	}
+
+	config.rsaPublicKey = key
+}
+
+// loadRSAPrivateKey loads the specifed private key file for decrypting file chunks
+func (config *Config) loadRSAPrivateKey(keyFile string, passphrase string) {
+
+	if config.rsaPublicKey == nil {
+		LOG_ERROR("RSA_PUBLIC", "The storage was not encrypted by an RSA key")
+		return
+	}
+
+	encodedKey := []byte(keyFile)
+	var err error
+
+	// keyFile may be the actually key, in which case we don't need to read from a file
+	if !strings.Contains(keyFile, "-----BEGIN") {
+		encodedKey, err = ioutil.ReadFile(keyFile)
+		if err != nil {
+			LOG_ERROR("RSA_PRIVATE", "Failed to read the private key file: %v", err)
+			return
+		}
+	}
+
+	decodedKey, _ := pem.Decode(encodedKey)
+	if decodedKey == nil {
+		LOG_ERROR("RSA_PRIVATE", "unrecognized private key in %s", keyFile)
+		return
+	}
+	if decodedKey.Type != "RSA PRIVATE KEY" {
+		LOG_ERROR("RSA_PRIVATE", "Unsupported private key type %s in %s", decodedKey.Type, keyFile)
+		return
+	}
+
+	var decodedKeyBytes []byte
+	if passphrase != "" {
+		decodedKeyBytes, err = x509.DecryptPEMBlock(decodedKey, []byte(passphrase))
+	} else {
+		decodedKeyBytes = decodedKey.Bytes
+	}
+
+	var parsedKey interface{}
+	if parsedKey, err = x509.ParsePKCS1PrivateKey(decodedKeyBytes); err != nil {
+		if parsedKey, err = x509.ParsePKCS8PrivateKey(decodedKeyBytes); err != nil {
+			LOG_ERROR("RSA_PRIVATE", "Failed to parse the private key in %s: %v", keyFile, err)
+			return
+		}
+	}
+
+	key, ok := parsedKey.(*rsa.PrivateKey)
+	if !ok {
+		LOG_ERROR("RSA_PRIVATE", "Unsupported private key type %s in %s", reflect.TypeOf(parsedKey), keyFile)
+		return
+	}
+
+	data := make([]byte, 32)
+	_, err = rand.Read(data)
+	if err != nil {
+		LOG_ERROR("RSA_PRIVATE", "Failed to generate random data for testing the private key: %v", err)
+		return
+	}
+
+	// Now test if the private key matches the public key
+	encryptedData, err := rsa.EncryptOAEP(sha256.New(), rand.Reader, config.rsaPublicKey, data, nil)
+	if err != nil {
+		LOG_ERROR("RSA_PRIVATE", "Failed to encrypt random data with the public key: %v", err)
+		return
+	}
+
+	decryptedData, err := rsa.DecryptOAEP(sha256.New(), rand.Reader, key, encryptedData, nil)
+	if err != nil {
+		LOG_ERROR("RSA_PRIVATE", "Incorrect private key: %v", err)
+		return
+	}
+
+	if !bytes.Equal(data, decryptedData) {
+		LOG_ERROR("RSA_PRIVATE", "Decrypted data do not match the original data")
+		return
+	}
+
+	config.rsaPrivateKey = key
 }

src/duplicacy_dropboxstorage.go

@@ -6,24 +6,26 @@ package duplicacy
 
 import (
 	"fmt"
-    "path"
+	"io/ioutil"
 	"strings"
+
 	"github.com/gilbertchen/go-dropbox"
 )
 
 type DropboxStorage struct {
-    RateLimitedStorage
+	StorageBase
 
 	clients        []*dropbox.Files
+	minimumNesting int // The minimum level of directories to dive into before searching for the chunk file.
 	storageDir     string
 }
 
 // CreateDropboxStorage creates a dropbox storage object.
-func CreateDropboxStorage(accessToken string, storageDir string, threads int) (storage *DropboxStorage, err error) {
+func CreateDropboxStorage(refreshToken string, storageDir string, minimumNesting int, threads int) (storage *DropboxStorage, err error) {
 
 	var clients []*dropbox.Files
 	for i := 0; i < threads; i++ {
-        client := dropbox.NewFiles(dropbox.NewConfig(accessToken))
+		client := dropbox.NewFiles(dropbox.NewConfig("", refreshToken, "https://duplicacy.com/dropbox_refresh"))
 		clients = append(clients, client)
 	}
 
@@ -38,6 +40,7 @@ func CreateDropboxStorage(accessToken string, storageDir string, threads int) (s
 	storage = &DropboxStorage{
 		clients:        clients,
 		storageDir:     storageDir,
+		minimumNesting: minimumNesting,
 	}
 
 	err = storage.CreateDirectory(0, "")
@@ -45,6 +48,8 @@ func CreateDropboxStorage(accessToken string, storageDir string, threads int) (s
 		return nil, fmt.Errorf("Can't create storage directory: %v", err)
 	}
 
+	storage.DerivedStorage = storage
+	storage.SetDefaultNestingLevels([]int{1}, 1)
 	return storage, nil
 }
 
@@ -85,7 +90,7 @@ func (storage *DropboxStorage) ListFiles(threadIndex int, dir string) (files []s
 
 		if output.HasMore {
 			output, err = storage.clients[threadIndex].ListFolderContinue(
-                              &dropbox.ListFolderContinueInput { Cursor: output.Cursor, })
+				&dropbox.ListFolderContinueInput{Cursor: output.Cursor})
 
 		} else {
 			break
@@ -178,66 +183,6 @@ func (storage *DropboxStorage) GetFileInfo(threadIndex int, filePath string) (ex
 	return true, output.Tag == "folder", int64(output.Size), nil
 }
 
-// FindChunk finds the chunk with the specified id.  If 'isFossil' is true, it will search for chunk files with
-// the suffix '.fsl'.
-func (storage *DropboxStorage) FindChunk(threadIndex int, chunkID string, isFossil bool) (filePath string, exist bool, size int64, err error) {
-     dir := "/chunks"
-
-    suffix := ""
-    if isFossil {
-        suffix = ".fsl"
-    }
-
-    // The minimum level of directories to dive into before searching for the chunk file.
-    minimumLevel := 1
-
-    for level := 0; level * 2 < len(chunkID); level ++ {
-        if level >= minimumLevel {
-            filePath = path.Join(dir, chunkID[2 * level:]) + suffix
-            var size int64
-            exist, _, size, err = storage.GetFileInfo(threadIndex, filePath)
-            if err != nil {
-                return "", false, 0, err
-            }
-            if exist {
-                return filePath, exist, size, nil
-            }
-        }
-
-        // Find the subdirectory the chunk file may reside.
-        subDir := path.Join(dir, chunkID[2 * level: 2 * level + 2])
-        exist, _, _, err = storage.GetFileInfo(threadIndex, subDir)
-        if err != nil {
-            return "", false, 0, err
-        }
-
-        if exist {
-            dir = subDir
-            continue
-        }
-
-        if level < minimumLevel {
-            // Create the subdirectory if it doesn't exist.
-            err = storage.CreateDirectory(threadIndex, subDir)
-            if err != nil {
-                return "", false, 0, err
-            }
-
-            dir = subDir
-            continue
-        }
-
-        // Teh chunk must be under this subdirectory but it doesn't exist.
-        return path.Join(dir, chunkID[2 * level:])[1:] + suffix, false, 0, nil
-
-    }
-
-    LOG_FATAL("CHUNK_FIND", "Chunk %s is still not found after having searched a maximum level of directories",
-              chunkID)
-    return "", false, 0, nil
-
-}
-
 // DownloadFile reads the file at 'filePath' into the chunk.
 func (storage *DropboxStorage) DownloadFile(threadIndex int, filePath string, chunk *Chunk) (err error) {
 
@@ -255,6 +200,7 @@ func (storage *DropboxStorage) DownloadFile(threadIndex int, filePath string, ch
 	}
 
 	defer output.Body.Close()
+	defer ioutil.ReadAll(output.Body)
 
 	_, err = RateLimitedCopy(chunk, output.Body, storage.DownloadRateLimit/len(storage.clients))
 	return err
@@ -281,16 +227,16 @@ func (storage *DropboxStorage) UploadFile(threadIndex int, filePath string, cont
 
 // If a local snapshot cache is needed for the storage to avoid downloading/uploading chunks too often when
 // managing snapshots.
-func (storage *DropboxStorage) IsCacheNeeded() (bool) { return true }
+func (storage *DropboxStorage) IsCacheNeeded() bool { return true }
 
 // If the 'MoveFile' method is implemented.
-func (storage *DropboxStorage) IsMoveFileImplemented() (bool) { return true }
+func (storage *DropboxStorage) IsMoveFileImplemented() bool { return true }
 
 // If the storage can guarantee strong consistency.
-func (storage *DropboxStorage) IsStrongConsistent() (bool) { return false }
+func (storage *DropboxStorage) IsStrongConsistent() bool { return false }
 
 // If the storage supports fast listing of files names.
-func (storage *DropboxStorage) IsFastListing() (bool) { return false }
+func (storage *DropboxStorage) IsFastListing() bool { return false }
 
 // Enable the test mode.
 func (storage *DropboxStorage) EnableTestMode() {}

src/duplicacy_entry.go

@@ -4,25 +4,32 @@
 package duplicacy
 
 import (
-    "os"
-    "fmt"
-    "path/filepath"
-    "io/ioutil"
-    "sort"
-    "regexp"
-    "strconv"
-    "time"
-    "encoding/json"
 	"encoding/base64"
+	"encoding/json"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"regexp"
+	"runtime"
+	"sort"
+	"strconv"
 	"strings"
+	"time"
+	"bytes"
+	"crypto/sha256"
+
+    "github.com/vmihailenco/msgpack"
 
 )
 
-
 // This is the hidden directory in the repository for storing various files.
 var DUPLICACY_DIRECTORY = ".duplicacy"
 var DUPLICACY_FILE = ".duplicacy"
 
+// Mask for file permission bits
+var fileModeMask = os.ModePerm | os.ModeSetuid | os.ModeSetgid | os.ModeSticky
+
 // Regex for matching 'StartChunk:StartOffset:EndChunk:EndOffset'
 var contentRegex = regexp.MustCompile(`^([0-9]+):([0-9]+):([0-9]+):([0-9]+)`)
 
@@ -43,7 +50,7 @@ type Entry struct {
 	EndChunk    int
 	EndOffset   int
 
-    Attributes map[string][]byte
+	Attributes *map[string][]byte
 }
 
 // CreateEntry creates an entry from file properties.
@@ -91,6 +98,27 @@ func CreateEntryFromFileInfo(fileInfo os.FileInfo, directory string) *Entry {
 	return entry
 }
 
+func (entry *Entry) Copy() *Entry {
+	return &Entry{
+		Path: entry.Path,
+		Size: entry.Size,
+		Time: entry.Time,
+		Mode: entry.Mode,
+		Link: entry.Link,
+		Hash: entry.Hash,
+
+		UID: entry.UID,
+		GID: entry.GID,
+
+		StartChunk: entry.StartChunk,
+		StartOffset: entry.StartOffset,
+		EndChunk: entry.EndChunk,
+		EndOffset: entry.EndOffset,
+
+		Attributes: entry.Attributes,
+	}
+}
+
 // CreateEntryFromJSON creates an entry from a json description.
 func (entry *Entry) UnmarshalJSON(description []byte) (err error) {
 
@@ -173,17 +201,17 @@ func (entry *Entry) UnmarshalJSON(description []byte) (err error) {
 		if attributes, ok := value.(map[string]interface{}); !ok {
 			return fmt.Errorf("Attributes are invalid for file '%s' in the snapshot", entry.Path)
 		} else {
-            entry.Attributes = make(map[string][]byte)
+			entry.Attributes = &map[string][]byte{}
 			for name, object := range attributes {
 				if object == nil {
-                    entry.Attributes[name] = []byte("")
+					(*entry.Attributes)[name] = []byte("")
 				} else if attributeInBase64, ok := object.(string); !ok {
 					return fmt.Errorf("Attribute '%s' is invalid for file '%s' in the snapshot", name, entry.Path)
 				} else if attribute, err := base64.StdEncoding.DecodeString(attributeInBase64); err != nil {
 					return fmt.Errorf("Failed to decode attribute '%s' for file '%s' in the snapshot: %v",
 						name, entry.Path, err)
 				} else {
-                    entry.Attributes[name] = attribute
+					(*entry.Attributes)[name] = attribute
 				}
 			}
 		}
@@ -242,7 +270,7 @@ func (entry *Entry) convertToObject(encodeName bool) map[string]interface{} {
 		object["gid"] = entry.GID
 	}
 
-    if len(entry.Attributes) > 0 {
+	if entry.Attributes != nil && len(*entry.Attributes) > 0 {
 		object["attributes"] = entry.Attributes
 	}
 
@@ -257,6 +285,197 @@ func (entry *Entry) MarshalJSON() ([] byte, error) {
 	return description, err
 }
 
+var _ msgpack.CustomEncoder = (*Entry)(nil)
+var _ msgpack.CustomDecoder = (*Entry)(nil)
+
+func (entry *Entry) EncodeMsgpack(encoder *msgpack.Encoder) error {
+
+	err := encoder.EncodeString(entry.Path)
+	if err != nil {
+		return err
+	}
+
+	err = encoder.EncodeInt(entry.Size)
+	if err != nil {
+		return err
+	}
+
+	err = encoder.EncodeInt(entry.Time)
+	if err != nil {
+		return err
+	}
+
+	err = encoder.EncodeInt(int64(entry.Mode))
+	if err != nil {
+		return err
+	}
+
+	err = encoder.EncodeString(entry.Link)
+	if err != nil {
+		return err
+	}
+
+	err = encoder.EncodeString(entry.Hash)
+	if err != nil {
+		return err
+	}
+
+	err = encoder.EncodeInt(int64(entry.StartChunk))
+	if err != nil {
+		return err
+	}
+
+	err = encoder.EncodeInt(int64(entry.StartOffset))
+	if err != nil {
+		return err
+	}
+
+	err = encoder.EncodeInt(int64(entry.EndChunk))
+	if err != nil {
+		return err
+	}
+
+	err = encoder.EncodeInt(int64(entry.EndOffset))
+	if err != nil {
+		return err
+	}
+
+	err = encoder.EncodeInt(int64(entry.UID))
+	if err != nil {
+		return err
+	}
+
+	err = encoder.EncodeInt(int64(entry.GID))
+	if err != nil {
+		return err
+	}
+
+	var numberOfAttributes int64
+	if entry.Attributes != nil {
+		numberOfAttributes = int64(len(*entry.Attributes))
+	}
+
+	err = encoder.EncodeInt(numberOfAttributes)
+	if err != nil {
+		return err
+	}
+
+	if entry.Attributes != nil {
+		attributes := make([]string, numberOfAttributes)
+        i := 0
+        for attribute := range *entry.Attributes {
+            attributes[i] = attribute
+            i++
+        }
+        sort.Strings(attributes)
+		for _, attribute := range attributes {
+			err = encoder.EncodeString(attribute)
+			if err != nil {
+				return err
+			}
+			err = encoder.EncodeString(string((*entry.Attributes)[attribute]))
+			if err != nil {
+				return err
+			}
+		}
+	}
+
+    return nil
+}
+
+func (entry *Entry) DecodeMsgpack(decoder *msgpack.Decoder) error {
+
+	var err error
+
+	entry.Path, err = decoder.DecodeString()
+	if err != nil {
+		return err
+	}
+
+	entry.Size, err = decoder.DecodeInt64()
+	if err != nil {
+		return err
+	}
+
+	entry.Time, err = decoder.DecodeInt64()
+	if err != nil {
+		return err
+	}
+
+	mode, err := decoder.DecodeInt64()
+	if err != nil {
+		return err
+	}
+	entry.Mode = uint32(mode)
+
+	entry.Link, err = decoder.DecodeString()
+	if err != nil {
+		return err
+	}
+
+	entry.Hash, err = decoder.DecodeString()
+	if err != nil {
+		return err
+	}
+
+	startChunk, err := decoder.DecodeInt()
+	if err != nil {
+		return err
+	}
+	entry.StartChunk = int(startChunk)
+
+	startOffset, err := decoder.DecodeInt()
+	if err != nil {
+		return err
+	}
+	entry.StartOffset = int(startOffset)
+
+	endChunk, err := decoder.DecodeInt()
+	if err != nil {
+		return err
+	}
+	entry.EndChunk = int(endChunk)
+
+	endOffset, err := decoder.DecodeInt()
+	if err != nil {
+		return err
+	}
+	entry.EndOffset = int(endOffset)
+
+	uid, err := decoder.DecodeInt()
+	if err != nil {
+		return err
+	}
+	entry.UID = int(uid)
+
+	gid, err := decoder.DecodeInt()
+	if err != nil {
+		return err
+	}
+	entry.GID = int(gid)
+
+	numberOfAttributes, err := decoder.DecodeInt()
+	if err != nil {
+		return err
+	}
+
+	if numberOfAttributes > 0 {
+		entry.Attributes = &map[string][]byte{}
+		for i := 0; i < numberOfAttributes; i++ {
+			attribute, err := decoder.DecodeString()
+			if err != nil {
+				return err
+			}
+			value, err := decoder.DecodeString()
+			if err != nil {
+				return err
+			}
+			(*entry.Attributes)[attribute] = []byte(value)
+		}
+	}
+	return nil
+}
+
 func (entry *Entry) IsFile() bool {
 	return entry.Mode&uint32(os.ModeType) == 0
 }
@@ -269,8 +488,25 @@ func (entry *Entry) IsLink() bool {
 	return entry.Mode&uint32(os.ModeSymlink) != 0
 }
 
+func (entry *Entry) IsComplete() bool {
+	return entry.Size >= 0
+}
+
 func (entry *Entry) GetPermissions() os.FileMode {
-    return os.FileMode(entry.Mode) & os.ModePerm
+	return os.FileMode(entry.Mode) & fileModeMask
+}
+
+func (entry *Entry) GetParent() string {
+	path := entry.Path
+	if path != "" && path[len(path) - 1] == '/' {
+		path = path[:len(path) - 1]
+	}
+	i := strings.LastIndex(path, "/")
+	if i == -1 {
+		return ""
+	} else {
+		return path[:i]
+	}
 }
 
 func (entry *Entry) IsSameAs(other *Entry) bool {
@@ -287,10 +523,10 @@ func (entry *Entry) String(maxSizeDigits int) string {
 	return fmt.Sprintf("%*d %s %64s %s", maxSizeDigits, entry.Size, modifiedTime, entry.Hash, entry.Path)
 }
 
-func (entry *Entry) RestoreMetadata(fullPath string, fileInfo *os.FileInfo) bool {
+func (entry *Entry) RestoreMetadata(fullPath string, fileInfo *os.FileInfo, setOwner bool) bool {
 
 	if fileInfo == nil {
-        stat, err := os.Stat(fullPath)
+		stat, err := os.Lstat(fullPath)
 		fileInfo = &stat
 		if err != nil {
 			LOG_ERROR("RESTORE_STAT", "Failed to retrieve the file info: %v", err)
@@ -298,7 +534,15 @@ func (entry *Entry) RestoreMetadata(fullPath string, fileInfo *os.FileInfo) bool
 		}
 	}
 
-    if (*fileInfo).Mode() & os.ModePerm != entry.GetPermissions() {
+	// Note that chown can remove setuid/setgid bits so should be called before chmod
+	if setOwner {
+		if !SetOwner(fullPath, entry, fileInfo) {
+			return false
+		}
+	}
+
+	// Only set the permission if the file is not a symlink
+	if !entry.IsLink() && (*fileInfo).Mode()&fileModeMask != entry.GetPermissions() {
 		err := os.Chmod(fullPath, entry.GetPermissions())
 		if err != nil {
 			LOG_ERROR("RESTORE_CHMOD", "Failed to set the file permissions: %v", err)
@@ -306,7 +550,8 @@ func (entry *Entry) RestoreMetadata(fullPath string, fileInfo *os.FileInfo) bool
 		}
 	}
 
-    if (*fileInfo).ModTime().Unix() != entry.Time {
+	// Only set the time if the file is not a symlink
+	if !entry.IsLink() && (*fileInfo).ModTime().Unix() != entry.Time {
 		modifiedTime := time.Unix(entry.Time, 0)
 		err := os.Chtimes(fullPath, modifiedTime, modifiedTime)
 		if err != nil {
@@ -315,57 +560,71 @@ func (entry *Entry) RestoreMetadata(fullPath string, fileInfo *os.FileInfo) bool
 		}
 	}
 
-    if len(entry.Attributes) > 0 {
+	if entry.Attributes != nil && len(*entry.Attributes) > 0 {
 		entry.SetAttributesToFile(fullPath)
 	}
 
-    return SetOwner(fullPath, entry, fileInfo)
+	return true
 }
 
-
 // Return -1 if 'left' should appear before 'right', 1 if opposite, and 0 if they are the same.
 // Files are always arranged before subdirectories under the same parent directory.
-func (left *Entry) Compare(right *Entry) int {
-
-    path1 := left.Path
-    path2 := right.Path
 
+func ComparePaths(left string, right string) int {
 	p := 0
-    for ; p < len(path1) && p < len(path2); p++ {
-        if path1[p] != path2[p] {
+	for ; p < len(left) && p < len(right); p++ {
+		if left[p] != right[p] {
 			break
 		}
 	}
 
-    // c1, c2 is the first byte that differs
+	// c1, c2 are the first bytes that differ
 	var c1, c2 byte
-    if p < len(path1) {
-        c1 = path1[p]
+	if p < len(left) {
+		c1 = left[p]
 	}
-    if p < len(path2) {
-        c2 = path2[p]
+	if p < len(right) {
+		c2 = right[p]
 	}
 
-    // c3, c4 indicates how the current component ends
-    // c3 == '/':  the current component is a directory
-    // c3 != '/':  the current component is the last one
+	// c3, c4 indicate how the current component ends
+	// c3 == '/':  the current component is a directory; c3 != '/':  the current component is the last one
 	c3 := c1
-    for i := p; c3 != '/' && i < len(path1); i++ {
-        c3 = path1[i]
+
+	// last1, last2 means if the current compoent is the last component
+	last1 := true
+	for i := p; i < len(left); i++ {
+		c3 = left[i]
+		if c3 == '/' {
+			last1 = i == len(left) - 1
+			break
+		}
 	}
 
 	c4 := c2
-    for i := p; c4 != '/' && i < len(path2); i++ {
-        c4 = path2[i]
+	last2 := true
+	for i := p; i < len(right); i++ {
+		c4 = right[i]
+		if c4 == '/' {
+			last2 = i == len(right) - 1
+			break
+		}
+	}
+
+	if last1 != last2 {
+		if last1 {
+			return -1
+		} else {
+			return 1
+		}
 	}
 
 	if c3 == '/' {
 		if c4 == '/' {
 			// We are comparing two directory components
 			if c1 == '/' {
-                // left is shorter
-                // Note that c2 maybe smaller than c1 but c1 is '/' which is counted
-                // as 0
+				// left is shorter; note that c2 maybe smaller than c1 but c1 should be treated as 0 therefore
+				// this is a special case that must be handled separately
 				return -1
 			} else if c2 == '/' {
 				// right is shorter
@@ -387,6 +646,10 @@ func (left *Entry) Compare(right *Entry) int {
 	}
 }
 
+func (left *Entry) Compare(right *Entry) int {
+	return ComparePaths(left.Path, right.Path)
+}
+
 // This is used to sort entries by their names.
 type ByName []*Entry
 
@@ -433,7 +696,7 @@ func (files FileInfoCompare) Less(i, j int) bool {
 
 // ListEntries returns a list of entries representing file and subdirectories under the directory 'path'.  Entry paths
 // are normalized as relative to 'top'.  'patterns' are used to exclude or include certain files.
-func ListEntries(top string, path string, fileList *[]*Entry, patterns [] string, discardAttributes bool) (directoryList []*Entry,
+func ListEntries(top string, path string, patterns []string, nobackupFile string, excludeByAttribute bool, listingChannel chan *Entry) (directoryList []*Entry,
 	skippedFiles []string, err error) {
 
 	LOG_DEBUG("LIST_ENTRIES", "Listing %s", path)
@@ -447,6 +710,15 @@ func ListEntries(top string, path string, fileList *[]*Entry, patterns [] string
 		return directoryList, nil, err
 	}
 
+	// This binary search works because ioutil.ReadDir returns files sorted by Name() by default
+	if nobackupFile != "" {
+		ii := sort.Search(len(files), func(ii int) bool { return strings.Compare(files[ii].Name(), nobackupFile) >= 0 })
+		if ii < len(files) && files[ii].Name() == nobackupFile {
+			LOG_DEBUG("LIST_NOBACKUP", "%s is excluded due to nobackup file", path)
+			return directoryList, skippedFiles, nil
+		}
+	}
+
 	normalizedPath := path
 	if len(normalizedPath) > 0 && normalizedPath[len(normalizedPath)-1] != '/' {
 		normalizedPath += "/"
@@ -459,20 +731,17 @@ func ListEntries(top string, path string, fileList *[]*Entry, patterns [] string
 
 	sort.Sort(FileInfoCompare(files))
 
-    entries := make([]*Entry, 0, 4)
-
 	for _, f := range files {
 		if f.Name() == DUPLICACY_DIRECTORY {
 			continue
 		}
 		entry := CreateEntryFromFileInfo(f, normalizedPath)
 		if len(patterns) > 0 && !MatchPath(entry.Path, patterns) {
-            LOG_DEBUG("LIST_EXCLUDE", "%s is excluded", entry.Path)
 			continue
 		}
 		if entry.IsLink() {
 			isRegular := false
-            isRegular, entry.Link, err = Readlink(filepath.Join(top, entry.Path))
+			isRegular, entry.Link, err = Readlink(joinPath(top, entry.Path))
 			if err != nil {
 				LOG_WARN("LIST_LINK", "Failed to read the symlink %s: %v", entry.Path, err)
 				skippedFiles = append(skippedFiles, entry.Path)
@@ -481,19 +750,32 @@ func ListEntries(top string, path string, fileList *[]*Entry, patterns [] string
 
 			if isRegular {
 				entry.Mode ^= uint32(os.ModeSymlink)
-            } else if path == "" && filepath.IsAbs(entry.Link) && !strings.HasPrefix(entry.Link, normalizedTop) {
-                stat, err := os.Stat(filepath.Join(top, entry.Path))
+			} else if path == "" && (filepath.IsAbs(entry.Link) || filepath.HasPrefix(entry.Link, `\\`)) && !strings.HasPrefix(entry.Link, normalizedTop) {
+				stat, err := os.Stat(joinPath(top, entry.Path))
 				if err != nil {
 					LOG_WARN("LIST_LINK", "Failed to read the symlink: %v", err)
 					skippedFiles = append(skippedFiles, entry.Path)
 					continue
 				}
-                entry = CreateEntryFromFileInfo(stat, "")
+
+				newEntry := CreateEntryFromFileInfo(stat, "")
+				if runtime.GOOS == "windows" {
+					// On Windows, stat.Name() is the last component of the target, so we need to construct the correct
+					// path from f.Name(); note that a "/" is append assuming a symbolic link is always a directory
+					newEntry.Path = filepath.Join(normalizedPath, f.Name()) + "/"
+				}
+				if len(patterns) > 0 && !MatchPath(newEntry.Path, patterns) {
+					continue
+				}
+				entry = newEntry
 			}
 		}
 
-        if !discardAttributes {
 		entry.ReadAttributes(top)
+
+		if excludeByAttribute && entry.Attributes != nil && excludedByAttribute(*entry.Attributes) {
+			LOG_DEBUG("LIST_EXCLUDE", "%s is excluded by attribute", entry.Path)
+			continue
 		}
 
 		if f.Mode()&(os.ModeNamedPipe|os.ModeSocket|os.ModeDevice) != 0 {
@@ -502,20 +784,20 @@ func ListEntries(top string, path string, fileList *[]*Entry, patterns [] string
 			continue
 		}
 
-        entries = append(entries, entry)
+		if entry.IsDir() {
+			directoryList = append(directoryList, entry)
+		} else {
+			listingChannel <- entry
+		}
 	}
 
 	// For top level directory we need to sort again because symlinks may have been changed
 	if path == "" {
-        sort.Sort(ByName(entries))
+		sort.Sort(ByName(directoryList))
 	}
 
-    for _, entry := range entries {
-        if entry.IsDir() {
-            directoryList = append(directoryList, entry)
-        } else {
-            *fileList = append(*fileList, entry)
-        }
+	for _, entry := range directoryList {
+		listingChannel <- entry
 	}
 
 	for i, j := 0, len(directoryList)-1; i < j; i, j = i+1, j-1 {
@@ -564,3 +846,100 @@ func (entry *Entry) Diff(chunkHashes[]string, chunkLengths[]int,
 
 	return modifiedLength
 }
+
+func (entry *Entry) EncodeWithHash(encoder *msgpack.Encoder) error {
+	entryBytes, err := msgpack.Marshal(entry)
+	if err != nil {
+		return err
+	}
+	hash := sha256.Sum256(entryBytes)
+	err = encoder.EncodeBytes(entryBytes)
+	if err != nil {
+		return err
+	}
+	err = encoder.EncodeBytes(hash[:])
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+func DecodeEntryWithHash(decoder *msgpack.Decoder) (*Entry, error) {
+	entryBytes, err := decoder.DecodeBytes()
+	if err != nil {
+		return nil, err
+	}
+	hashBytes, err := decoder.DecodeBytes()
+	if err != nil {
+		return nil, err
+	}
+	expectedHash := sha256.Sum256(entryBytes)
+	if bytes.Compare(expectedHash[:], hashBytes) != 0 {
+		return nil, fmt.Errorf("corrupted file metadata")
+	}
+
+	var entry Entry
+	err = msgpack.Unmarshal(entryBytes, &entry)
+	if err != nil {
+		return nil, err
+	}
+	return &entry, nil
+}
+
+func (entry *Entry) check(chunkLengths []int) error {
+
+	if entry.Size < 0 {
+		return fmt.Errorf("The file %s hash an invalid size (%d)", entry.Path, entry.Size)
+	}
+
+	if !entry.IsFile() || entry.Size == 0 {
+		return nil
+	}
+
+	if entry.StartChunk < 0 {
+		return fmt.Errorf("The file %s starts at chunk %d", entry.Path, entry.StartChunk)
+	}
+
+	if entry.EndChunk >= len(chunkLengths) {
+		return fmt.Errorf("The file %s ends at chunk %d while the number of chunks is %d",
+			entry.Path, entry.EndChunk, len(chunkLengths))
+	}
+
+	if entry.EndChunk < entry.StartChunk {
+		return fmt.Errorf("The file %s starts at chunk %d and ends at chunk %d",
+			entry.Path, entry.StartChunk, entry.EndChunk)
+	}
+
+	if entry.StartOffset >= chunkLengths[entry.StartChunk] {
+		return fmt.Errorf("The file %s starts at offset %d of chunk %d of length %d",
+			entry.Path, entry.StartOffset, entry.StartChunk, chunkLengths[entry.StartChunk])
+	}
+
+	if entry.EndOffset > chunkLengths[entry.EndChunk] {
+		return fmt.Errorf("The file %s ends at offset %d of chunk %d of length %d",
+			entry.Path, entry.EndOffset, entry.EndChunk, chunkLengths[entry.EndChunk])
+	}
+
+	fileSize := int64(0)
+
+	for i := entry.StartChunk; i <= entry.EndChunk; i++ {
+
+		start := 0
+		if i == entry.StartChunk {
+			start = entry.StartOffset
+		}
+		end := chunkLengths[i]
+		if i == entry.EndChunk {
+			end = entry.EndOffset
+		}
+
+		fileSize += int64(end - start)
+	}
+
+	if entry.Size != fileSize {
+		return fmt.Errorf("The file %s has a size of %d but the total size of chunks is %d",
+			entry.Path, entry.Size, fileSize)
+	}
+
+	return nil
+}

src/duplicacy_entry_test.go

@@ -5,12 +5,19 @@
 package duplicacy
 
 import (
-    "testing"
 	"io/ioutil"
+	"math/rand"
 	"os"
 	"path/filepath"
-    "math/rand"
+	"runtime"
 	"sort"
+	"strings"
+	"testing"
+	"bytes"
+	"encoding/json"
+
+	"github.com/gilbertchen/xattr"
+    "github.com/vmihailenco/msgpack"
 )
 
 func TestEntrySort(t *testing.T) {
@@ -23,19 +30,19 @@ func TestEntrySort(t *testing.T) {
 		"\xBB\xDDfile",
 		"\xFF\xDDfile",
 		"ab/",
+		"ab-/",
+		"ab0/",
+		"ab1/",
 		"ab/c",
 		"ab+/c-",
 		"ab+/c0",
 		"ab+/c/",
-        "ab+/c/d",
 		"ab+/c+/",
-        "ab+/c+/d",
 		"ab+/c0/",
+		"ab+/c/d",
+		"ab+/c+/d",
 		"ab+/c0/d",
-        "ab-/",
 		"ab-/c",
-        "ab0/",
-        "ab1/",
 		"ab1/c",
 		"ab1/\xBB\xDDfile",
 		"ab1/\xFF\xDDfile",
@@ -82,7 +89,7 @@ func TestEntrySort(t *testing.T) {
 	}
 }
 
-func TestEntryList(t *testing.T) {
+func TestEntryOrder(t *testing.T) {
 
 	testDir := filepath.Join(os.TempDir(), "duplicacy_test")
 	os.RemoveAll(testDir)
@@ -94,20 +101,19 @@ func TestEntryList(t *testing.T) {
 		"ab0",
 		"ab1",
 		"ab+/",
+		"ab2/",
+		"ab3/",
 		"ab+/c",
 		"ab+/c+",
 		"ab+/c1",
 		"ab+/c-/",
-        "ab+/c-/d",
 		"ab+/c0/",
+		"ab+/c-/d",
 		"ab+/c0/d",
-        "ab2/",
 		"ab2/c",
-        "ab3/",
 		"ab3/c",
 	}
 
-
 	var entry1, entry2 *Entry
 
 	for i, p1 := range DATA {
@@ -169,18 +175,24 @@ func TestEntryList(t *testing.T) {
 	directories = append(directories, CreateEntry("", 0, 0, 0))
 
 	entries := make([]*Entry, 0, 4)
+    entryChannel := make(chan *Entry, 1024)
+	entries = append(entries, CreateEntry("", 0, 0, 0))
 
 	for len(directories) > 0 {
 		directory := directories[len(directories)-1]
 		directories = directories[:len(directories)-1]
-        entries = append(entries, directory)
-        subdirectories, _, err := ListEntries(testDir, directory.Path, &entries, nil, false)
+		subdirectories, _, err := ListEntries(testDir, directory.Path, nil, "", false, entryChannel)
 		if err != nil {
 			t.Errorf("ListEntries(%s, %s) returned an error: %s", testDir, directory.Path, err)
 		}
 		directories = append(directories, subdirectories...)
 	}
 
+	close(entryChannel)
+	for entry := range entryChannel {
+		entries = append(entries, entry)
+	}
+
 	entries = entries[1:]
 
 	for _, entry := range entries {
@@ -218,3 +230,146 @@ func TestEntryList(t *testing.T) {
 
 }
 
+// TestEntryExcludeByAttribute tests the excludeByAttribute parameter to the ListEntries function
+func TestEntryExcludeByAttribute(t *testing.T) {
+
+	if !(runtime.GOOS == "darwin" || runtime.GOOS == "linux") {
+		t.Skip("skipping test not darwin or linux")
+	}
+
+	testDir := filepath.Join(os.TempDir(), "duplicacy_test")
+
+	os.RemoveAll(testDir)
+	os.MkdirAll(testDir, 0700)
+
+	// Files or folders named with "exclude" below will have the exclusion attribute set on them
+	// When ListEntries is called with excludeByAttribute true, they should be excluded.
+	DATA := [...]string{
+		"excludefile",
+		"includefile",
+		"excludedir/",
+		"excludedir/file",
+		"includedir/",
+		"includedir/includefile",
+		"includedir/excludefile",
+	}
+
+	for _, file := range DATA {
+		fullPath := filepath.Join(testDir, file)
+		if file[len(file)-1] == '/' {
+			err := os.Mkdir(fullPath, 0700)
+			if err != nil {
+				t.Errorf("Mkdir(%s) returned an error: %s", fullPath, err)
+			}
+			continue
+		}
+
+		err := ioutil.WriteFile(fullPath, []byte(file), 0700)
+		if err != nil {
+			t.Errorf("WriteFile(%s) returned an error: %s", fullPath, err)
+		}
+	}
+
+	for _, file := range DATA {
+		fullPath := filepath.Join(testDir, file)
+		if strings.Contains(file, "exclude") {
+			xattr.Setxattr(fullPath, "com.apple.metadata:com_apple_backup_excludeItem", []byte("com.apple.backupd"))
+		}
+	}
+
+	for _, excludeByAttribute := range [2]bool{true, false} {
+		t.Logf("testing excludeByAttribute: %t", excludeByAttribute)
+		directories := make([]*Entry, 0, 4)
+		directories = append(directories, CreateEntry("", 0, 0, 0))
+
+		entries := make([]*Entry, 0, 4)
+		entryChannel := make(chan *Entry, 1024)
+		entries = append(entries, CreateEntry("", 0, 0, 0))
+
+		for len(directories) > 0 {
+			directory := directories[len(directories)-1]
+			directories = directories[:len(directories)-1]
+			subdirectories, _, err := ListEntries(testDir, directory.Path, nil, "", excludeByAttribute, entryChannel)
+			if err != nil {
+				t.Errorf("ListEntries(%s, %s) returned an error: %s", testDir, directory.Path, err)
+			}
+			directories = append(directories, subdirectories...)
+		}
+
+		close(entryChannel)
+
+		for entry := range entryChannel {
+			entries = append(entries, entry)
+		}
+
+		entries = entries[1:]
+
+		for _, entry := range entries {
+			t.Logf("entry: %s", entry.Path)
+		}
+
+		i := 0
+		for _, file := range DATA {
+			entryFound := false
+			var entry *Entry
+			for _, entry = range entries {
+				if entry.Path == file {
+					entryFound = true
+					break
+				}
+			}
+
+			if excludeByAttribute && strings.Contains(file, "exclude") {
+				if entryFound {
+					t.Errorf("file: %s, expected to be excluded but wasn't. attributes: %v", file, entry.Attributes)
+					i++
+				} else {
+					t.Logf("file: %s, excluded", file)
+				}
+			} else {
+				if entryFound {
+					t.Logf("file: %s, included. attributes: %v", file, entry.Attributes)
+					i++
+				} else {
+					t.Errorf("file: %s, expected to be included but wasn't", file)
+				}
+			}
+		}
+
+	}
+
+	if !t.Failed() {
+		os.RemoveAll(testDir)
+	}
+
+}
+
+func TestEntryEncoding(t *testing.T) {
+	buffer := new(bytes.Buffer)
+	encoder := msgpack.NewEncoder(buffer)
+
+	entry1 := CreateEntry("abcd", 1, 2, 0700)
+	err := encoder.Encode(entry1)
+	if err != nil {
+		t.Errorf("Failed to encode the entry: %v", err)
+		return
+	}
+
+	t.Logf("msgpack size: %d\n", len(buffer.Bytes()))
+	decoder := msgpack.NewDecoder(buffer)
+
+	description, _ := json.Marshal(entry1)
+	t.Logf("json size: %d\n", len(description))
+
+	var entry2 Entry
+	err = decoder.Decode(&entry2)
+	if err != nil {
+		t.Errorf("Failed to decode the entry: %v", err)
+		return
+	}
+
+	if entry1.Path != entry2.Path || entry1.Size != entry2.Size || entry1.Time != entry2.Time {
+		t.Error("Decoded entry is different than the original one")
+	}
+
+}

src/duplicacy_entrylist.go

@@ -0,0 +1,574 @@
+// Copyright (c) Acrosync LLC. All rights reserved.
+// Free for personal use and commercial trial
+// Commercial use requires per-user licenses available from https://duplicacy.com
+
+package duplicacy
+
+import (
+	"encoding/hex"
+	"encoding/binary"
+	"fmt"
+	"os"
+	"io"
+	"path"
+	"crypto/sha256"
+	"crypto/rand"	
+	"sync"
+
+    "github.com/vmihailenco/msgpack"
+)
+
+// This struct stores information about a file entry that has been modified
+type ModifiedEntry struct {
+	Path string
+	Size int64
+	Hash string
+}
+
+// EntryList is basically a list of entries, which can be kept in the memory, or serialized to a disk file,
+// depending on if maximumInMemoryEntries is reached.
+//
+// The idea behind the on-disk entry list is that entries are written to a disk file as they are coming in.
+// Entries that have been modified and thus need to be uploaded will have their Incomplete bit set (i.e., 
+// with a size of -1).  When the limit is reached, entries are moved to a disk file but ModifiedEntries and
+// UploadedChunks are still kept in memory.  When later entries are read from the entry list, incomplete 
+// entries are back-annotated with info from ModifiedEntries and UploadedChunk* before sending them out.
+
+type EntryList struct {
+	onDiskFile *os.File                     // the file to store entries
+	encoder *msgpack.Encoder                // msgpack encoder for entry serialization
+	entries []*Entry                        // in-memory entry list
+	
+	SnapshotID string                       // the snapshot id
+	Token string                            // this unique random token makes sure we read/write 
+	                                        // the same entry list
+	ModifiedEntries []ModifiedEntry         // entries that will be uploaded
+
+	UploadedChunkHashes []string            // chunks from entries that have been uploaded
+	UploadedChunkLengths []int              // chunk lengths from entries that have been uploaded
+	uploadedChunkLock sync.Mutex            // lock for UploadedChunkHashes and UploadedChunkLengths
+
+	PreservedChunkHashes []string           // chunks from entries not changed
+	PreservedChunkLengths []int             // chunk lengths from entries not changed
+
+	Checksum string                         // checksum of all entries to detect disk corruption
+
+	maximumInMemoryEntries int              // max in-memory entries
+	NumberOfEntries int64                   // number of entries (not including directories and links)
+	cachePath string                        // the directory for the on-disk file
+
+	// These 3 variables are used in entry infomation back-annotation
+	modifiedEntryIndex int                  // points to the current modified entry
+	uploadedChunkIndex int                  // counter for upload chunks
+	uploadedChunkOffset int                 // the start offset for the current modified entry
+
+}
+
+// Create a new entry list
+func CreateEntryList(snapshotID string, cachePath string, maximumInMemoryEntries int) (*EntryList, error) {
+
+	token := make([]byte, 16)
+	_, err := rand.Read(token)
+	if err != nil {
+		return nil, fmt.Errorf("Failed to create a random token: %v", err)
+	}
+
+	entryList := &EntryList {
+		SnapshotID: snapshotID,
+		maximumInMemoryEntries: maximumInMemoryEntries,
+		cachePath: cachePath,
+		Token: string(token),
+	}
+
+	return entryList, nil
+
+}
+
+// Create the on-disk entry list file
+func (entryList *EntryList)createOnDiskFile() error {
+	file, err := os.OpenFile(path.Join(entryList.cachePath, "incomplete_files"), os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0600)
+	if err != nil {
+		return fmt.Errorf("Failed to create on disk entry list: %v", err)
+	}
+
+	entryList.onDiskFile = file
+	entryList.encoder = msgpack.NewEncoder(file)
+
+	err = entryList.encoder.EncodeString(entryList.Token)
+	if err != nil {
+		return fmt.Errorf("Failed to create on disk entry list: %v", err)
+	}
+
+	for _, entry := range entryList.entries {
+		err = entry.EncodeWithHash(entryList.encoder)
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// Add an entry to the entry list
+func (entryList *EntryList)AddEntry(entry *Entry) error {
+
+	if !entry.IsDir() && !entry.IsLink() {
+		entryList.NumberOfEntries++
+	}
+
+	if !entry.IsComplete() {
+		if entry.IsDir() || entry.IsLink() {
+			entry.Size = 0
+		} else {
+			modifiedEntry := ModifiedEntry {
+				Path: entry.Path,
+				Size: -1,
+			}
+		
+			entryList.ModifiedEntries = append(entryList.ModifiedEntries, modifiedEntry)
+		}
+	}
+
+	if entryList.onDiskFile != nil {
+		return entry.EncodeWithHash(entryList.encoder)
+	} else {
+		entryList.entries = append(entryList.entries, entry)
+		if entryList.maximumInMemoryEntries >= 0 && len(entryList.entries) > entryList.maximumInMemoryEntries {
+			err := entryList.createOnDiskFile()
+			if err != nil {
+				return err
+			}
+		}
+	}
+
+	return nil
+}
+
+// Add a preserved chunk that belongs to files that have not been modified
+func (entryList *EntryList)AddPreservedChunk(chunkHash string, chunkSize int) {
+	entryList.PreservedChunkHashes = append(entryList.PreservedChunkHashes, chunkHash)
+	entryList.PreservedChunkLengths = append(entryList.PreservedChunkLengths, chunkSize)
+}
+
+// Add a chunk just uploaded (that belongs to files that have been modified)
+func (entryList *EntryList)AddUploadedChunk(chunkIndex int, chunkHash string, chunkSize int) {
+	entryList.uploadedChunkLock.Lock()
+
+	for len(entryList.UploadedChunkHashes) <= chunkIndex {
+		entryList.UploadedChunkHashes = append(entryList.UploadedChunkHashes, "")
+	}
+
+	for len(entryList.UploadedChunkLengths) <= chunkIndex {
+		entryList.UploadedChunkLengths = append(entryList.UploadedChunkLengths, 0)
+	}
+
+	entryList.UploadedChunkHashes[chunkIndex] = chunkHash
+	entryList.UploadedChunkLengths[chunkIndex] = chunkSize
+	entryList.uploadedChunkLock.Unlock()
+}
+
+// Close the on-disk file
+func (entryList *EntryList) CloseOnDiskFile() error {
+
+	if entryList.onDiskFile == nil {
+		return nil
+	}
+
+	err := entryList.onDiskFile.Sync()
+	if err != nil {
+		return err
+	}
+
+	err = entryList.onDiskFile.Close()
+	if err != nil {
+		return err
+	}
+
+	entryList.onDiskFile = nil
+	return nil
+}
+
+// Return the length of the `index`th chunk
+func (entryList *EntryList) getChunkLength(index int) int {
+	if index < len(entryList.PreservedChunkLengths) {
+		return entryList.PreservedChunkLengths[index]
+	} else {
+		return entryList.UploadedChunkLengths[index - len(entryList.PreservedChunkLengths)]
+	}
+}
+
+// Sanity check for each entry
+func (entryList *EntryList) checkEntry(entry *Entry) error {
+
+	if entry.Size < 0 {
+		return fmt.Errorf("the file %s hash an invalid size (%d)", entry.Path, entry.Size)
+	}
+
+	if !entry.IsFile() || entry.Size == 0 {
+		return nil
+	}
+
+	numberOfChunks := len(entryList.PreservedChunkLengths) + len(entryList.UploadedChunkLengths) 
+
+	if entry.StartChunk < 0 {
+		return fmt.Errorf("the file %s starts at chunk %d", entry.Path, entry.StartChunk)
+	}
+
+	if entry.EndChunk >= numberOfChunks {
+		return fmt.Errorf("the file %s ends at chunk %d while the number of chunks is %d",
+			entry.Path, entry.EndChunk, numberOfChunks)
+	}
+
+	if entry.EndChunk < entry.StartChunk {
+		return fmt.Errorf("the file %s starts at chunk %d and ends at chunk %d",
+			entry.Path, entry.StartChunk, entry.EndChunk)
+	}
+
+	if entry.StartOffset >= entryList.getChunkLength(entry.StartChunk) {
+		return fmt.Errorf("the file %s starts at offset %d of chunk %d with a length of %d",
+			entry.Path, entry.StartOffset, entry.StartChunk, entryList.getChunkLength(entry.StartChunk))
+	}
+
+	if entry.EndOffset > entryList.getChunkLength(entry.EndChunk) {
+		return fmt.Errorf("the file %s ends at offset %d of chunk %d with a length of %d",
+			entry.Path, entry.EndOffset, entry.EndChunk, entryList.getChunkLength(entry.EndChunk))
+	}
+
+	fileSize := int64(0)
+
+	for i := entry.StartChunk; i <= entry.EndChunk; i++ {
+
+		start := 0
+		if i == entry.StartChunk {
+			start = entry.StartOffset
+		}
+		end := entryList.getChunkLength(i)
+		if i == entry.EndChunk {
+			end = entry.EndOffset
+		}
+
+		fileSize += int64(end - start)
+	}
+
+	if entry.Size != fileSize {
+		return fmt.Errorf("the file %s has a size of %d but the total size of chunks is %d",
+			entry.Path, entry.Size, fileSize)
+	}
+
+	return nil
+}
+
+// An incomplete entry (with a size of -1) does not have 'startChunk', 'startOffset', 'endChunk', and 'endOffset'.  This function
+// is to fill in these information before sending the entry out.
+func (entryList *EntryList) fillAndSendEntry(entry *Entry, entryOut func(*Entry)error) (skipped bool, err error) {
+
+	if entry.IsComplete() {
+		err := entryList.checkEntry(entry)
+		if err != nil {
+			return false, err
+		}
+		return false, entryOut(entry)
+	}
+
+	if entryList.modifiedEntryIndex >= len(entryList.ModifiedEntries) {
+		return false, fmt.Errorf("Unexpected file index %d (%d modified files)", entryList.modifiedEntryIndex, len(entryList.ModifiedEntries))
+	}
+
+	modifiedEntry := &entryList.ModifiedEntries[entryList.modifiedEntryIndex]
+	entryList.modifiedEntryIndex++
+
+	if modifiedEntry.Path != entry.Path {
+		return false, fmt.Errorf("Unexpected file path %s when expecting %s", modifiedEntry.Path, entry.Path)
+	}
+
+	if modifiedEntry.Size <= 0 {
+		return true, nil
+	}
+
+	entry.Size = modifiedEntry.Size
+	entry.Hash = modifiedEntry.Hash
+
+	entry.StartChunk = entryList.uploadedChunkIndex + len(entryList.PreservedChunkHashes)
+	entry.StartOffset = entryList.uploadedChunkOffset
+	entry.EndChunk = entry.StartChunk
+	endOffset := int64(entry.StartOffset) + entry.Size
+
+	for entryList.uploadedChunkIndex < len(entryList.UploadedChunkLengths) && endOffset > int64(entryList.UploadedChunkLengths[entryList.uploadedChunkIndex]) {
+		endOffset -= int64(entryList.UploadedChunkLengths[entryList.uploadedChunkIndex])
+		entry.EndChunk++
+		entryList.uploadedChunkIndex++
+	}
+
+	if entryList.uploadedChunkIndex >= len(entryList.UploadedChunkLengths) {
+		return false, fmt.Errorf("File %s has not been completely uploaded", entry.Path)
+	}
+
+	entry.EndOffset = int(endOffset)
+	entryList.uploadedChunkOffset = entry.EndOffset 
+	if entry.EndOffset == entryList.UploadedChunkLengths[entryList.uploadedChunkIndex] {
+		entryList.uploadedChunkIndex++
+		entryList.uploadedChunkOffset = 0
+	}
+
+	err = entryList.checkEntry(entry)
+	if err != nil {
+		return false, err
+	}
+
+	return false, entryOut(entry)
+}
+
+// Iterate through the entries in this entry list
+func (entryList *EntryList) ReadEntries(entryOut func(*Entry)error) (error) {
+
+	entryList.modifiedEntryIndex = 0
+	entryList.uploadedChunkIndex = 0
+	entryList.uploadedChunkOffset = 0
+
+	if entryList.onDiskFile == nil {
+		for _, entry := range entryList.entries {
+			skipped, err := entryList.fillAndSendEntry(entry.Copy(), entryOut)
+			if err != nil {
+				return err
+			}
+			if skipped {
+				continue
+			}
+		}
+	} else {
+		_, err := entryList.onDiskFile.Seek(0, os.SEEK_SET)
+		if err != nil {
+			return err
+		}
+		decoder := msgpack.NewDecoder(entryList.onDiskFile)
+
+		_, err = decoder.DecodeString()
+		if err != nil {
+			return err
+		}
+	
+    	for _, err = decoder.PeekCode(); err == nil; _, err = decoder.PeekCode() {	
+			entry, err := DecodeEntryWithHash(decoder)
+			if err != nil {
+				return err
+			}
+			skipped, err := entryList.fillAndSendEntry(entry, entryOut)
+			if err != nil {
+				return err
+			}
+			if skipped {
+				continue
+			}
+		}
+
+		if err != io.EOF {
+			return err
+		}
+	}
+
+	return nil
+}
+
+// When saving an incomplete snapshot, the on-disk entry list ('incomplete_files') is renamed to
+// 'incomplete_snapshot', and this EntryList struct is saved as 'incomplete_chunks'.
+func (entryList *EntryList) SaveIncompleteSnapshot() {
+	entryList.uploadedChunkLock.Lock()
+	defer entryList.uploadedChunkLock.Unlock()
+
+	if entryList.onDiskFile == nil {
+		err := entryList.createOnDiskFile()
+		if err != nil {
+			LOG_WARN("INCOMPLETE_SAVE", "Failed to create the incomplete snapshot file: %v", err)
+			return
+		}
+
+		for _, entry := range entryList.entries {
+
+			err = entry.EncodeWithHash(entryList.encoder)
+			if err != nil {
+				LOG_WARN("INCOMPLETE_SAVE", "Failed to save the entry %s: %v", entry.Path, err)
+				return
+			}
+		}
+	}
+
+	err := entryList.onDiskFile.Close()
+	if err != nil {
+		LOG_WARN("INCOMPLETE_SAVE", "Failed to close the on-disk file: %v", err)
+		return
+	}
+
+	filePath := path.Join(entryList.cachePath, "incomplete_snapshot")
+	if _, err := os.Stat(filePath); err == nil {
+		err = os.Remove(filePath)
+		if err != nil {
+			LOG_WARN("INCOMPLETE_REMOVE", "Failed to remove previous incomplete snapshot: %v", err)
+		}
+	}
+
+	err = os.Rename(path.Join(entryList.cachePath, "incomplete_files"), filePath)
+	if err != nil {
+		LOG_WARN("INCOMPLETE_SAVE", "Failed to rename the incomplete snapshot file: %v", err)
+		return
+	}
+
+	chunkFile := path.Join(entryList.cachePath, "incomplete_chunks")
+	file, err := os.OpenFile(chunkFile, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0600)
+	if err != nil {
+		LOG_WARN("INCOMPLETE_SAVE", "Failed to create the incomplete chunk file: %v", err)
+		return
+	}
+
+	defer file.Close()
+	encoder := msgpack.NewEncoder(file)
+
+	entryList.Checksum = entryList.CalculateChecksum()
+
+	err = encoder.Encode(entryList)
+	if err != nil {
+		LOG_WARN("INCOMPLETE_SAVE", "Failed to save the incomplete snapshot: %v", err)
+		return
+	}
+
+	LOG_INFO("INCOMPLETE_SAVE", "Incomplete snapshot saved to %s", filePath)	
+}
+
+// Calculate a checksum for this entry list
+func (entryList *EntryList) CalculateChecksum() string{
+
+	hasher := sha256.New()
+	for _, s := range entryList.UploadedChunkHashes {
+		hasher.Write([]byte(s))
+	}
+
+	buffer := make([]byte, 8)
+	for _, i := range entryList.UploadedChunkLengths {
+		binary.LittleEndian.PutUint64(buffer, uint64(i))
+		hasher.Write(buffer)
+	}
+
+	for _, s := range entryList.PreservedChunkHashes {
+		hasher.Write([]byte(s))
+	}
+
+	for _, i := range entryList.PreservedChunkLengths {
+		binary.LittleEndian.PutUint64(buffer, uint64(i))
+		hasher.Write(buffer)
+	}
+
+	for _, entry := range entryList.ModifiedEntries {
+		binary.LittleEndian.PutUint64(buffer, uint64(entry.Size))
+		hasher.Write(buffer)
+		hasher.Write([]byte(entry.Hash))
+	}
+
+	return hex.EncodeToString(hasher.Sum(nil))
+}
+
+// Check if all chunks exist in 'chunkCache'
+func (entryList *EntryList) CheckChunks(config *Config, chunkCache map[string]bool) bool {
+	for _, chunkHash := range entryList.UploadedChunkHashes {
+		chunkID := config.GetChunkIDFromHash(chunkHash)
+		if _, ok := chunkCache[chunkID]; !ok {
+			return false
+		}
+	}
+	for _, chunkHash := range entryList.PreservedChunkHashes {
+		chunkID := config.GetChunkIDFromHash(chunkHash)
+		if _, ok := chunkCache[chunkID]; !ok {
+			return false
+		}
+	}
+
+	return true
+
+}
+
+// Recover the on disk file from 'incomplete_snapshot', and restore the EntryList struct
+// from 'incomplete_chunks'
+func loadIncompleteSnapshot(snapshotID string, cachePath string) *EntryList {
+
+	onDiskFilePath := path.Join(cachePath, "incomplete_snapshot")
+	entryListFilePath := path.Join(cachePath, "incomplete_chunks")
+
+	if _, err := os.Stat(onDiskFilePath); os.IsNotExist(err) {
+		return nil
+	}
+
+	if _, err := os.Stat(entryListFilePath); os.IsNotExist(err) {
+		return nil
+	}
+
+	entryList := &EntryList {}
+	entryListFile, err := os.OpenFile(entryListFilePath, os.O_RDONLY, 0600)
+	if err != nil {
+		LOG_WARN("INCOMPLETE_LOAD", "Failed to open the incomplete snapshot: %v", err)
+		return nil
+	}
+
+	defer entryListFile.Close()
+	decoder := msgpack.NewDecoder(entryListFile)
+	err = decoder.Decode(&entryList)
+	if err != nil {
+		LOG_WARN("INCOMPLETE_LOAD", "Failed to load the incomplete snapshot: %v", err)
+		return nil
+	}
+
+	checksum := entryList.CalculateChecksum()
+	if checksum != entryList.Checksum {
+		LOG_WARN("INCOMPLETE_LOAD", "Failed to load the incomplete snapshot: checksum mismatched")
+		return nil
+	}
+
+	onDiskFile, err := os.OpenFile(onDiskFilePath, os.O_RDONLY, 0600)
+	if err != nil {
+		LOG_WARN("INCOMPLETE_LOAD", "Failed to open the on disk file for the incomplete snapshot: %v", err)
+		return nil
+	}
+
+	decoder = msgpack.NewDecoder(onDiskFile)
+	token, err := decoder.DecodeString()
+	if err != nil {
+		LOG_WARN("INCOMPLETE_LOAD", "Failed to read the token for the incomplete snapshot: %v", err)
+		onDiskFile.Close()
+		return nil
+	}
+
+	if token != entryList.Token {
+		LOG_WARN("INCOMPLETE_LOAD", "Mismatched tokens in the incomplete snapshot")
+		onDiskFile.Close()
+		return nil
+	}
+
+	entryList.onDiskFile = onDiskFile
+
+	for i, hash := range entryList.UploadedChunkHashes {
+		if len(hash) == 0 {
+			// An empty hash means the chunk has not been uploaded in previous run
+			entryList.UploadedChunkHashes = entryList.UploadedChunkHashes[0:i]
+			entryList.UploadedChunkLengths = entryList.UploadedChunkLengths[0:i]
+			break
+		}
+	}
+
+	LOG_INFO("INCOMPLETE_LOAD", "Previous incomplete backup contains %d files and %d chunks",
+	         entryList.NumberOfEntries, len(entryList.PreservedChunkLengths) + len(entryList.UploadedChunkHashes))
+
+	return entryList
+}
+
+// Delete the two incomplete files.
+func deleteIncompleteSnapshot(cachePath string) {
+
+	for _, file := range []string{"incomplete_snapshot", "incomplete_chunks"} {
+		filePath := path.Join(cachePath, file)
+		if _, err := os.Stat(filePath); err == nil {
+			err = os.Remove(filePath)
+			if err != nil {
+				LOG_WARN("INCOMPLETE_REMOVE", "Failed to remove the incomplete snapshot: %v", err)
+				return
+			}
+		}
+	}
+
+
+}

src/duplicacy_entrylist_test.go

@@ -0,0 +1,179 @@
+// Copyright (c) Acrosync LLC. All rights reserved.
+// Free for personal use and commercial trial
+// Commercial use requires per-user licenses available from https://duplicacy.com
+
+package duplicacy
+
+import (
+	"os"
+	"path"
+	"time"
+	"testing"
+	"math/rand"
+)
+
+
+func generateRandomString(length int) string {
+	var letters = []rune("abcdefghijklmnopqrstuvwxyz")
+    b := make([]rune, length)
+    for i := range b {
+        b[i] = letters[rand.Intn(len(letters))]
+    }
+    return string(b)
+}
+
+var fileSizeGenerator = rand.NewZipf(rand.New(rand.NewSource(time.Now().UnixNano())), 1.2, 1.0, 1024)
+
+func generateRandomFileSize() int64 {
+	return int64(fileSizeGenerator.Uint64() + 1)
+}
+
+func generateRandomChunks(totalFileSize int64) (chunks []string, lengths []int) {
+
+	totalChunkSize := int64(0)
+
+	for totalChunkSize < totalFileSize {
+		chunks = append(chunks, generateRandomString(64))
+		chunkSize := int64(1 + (rand.Int() % 64))
+		if chunkSize + totalChunkSize > totalFileSize {
+			chunkSize = totalFileSize - totalChunkSize
+		}
+		lengths = append(lengths, int(chunkSize))
+		totalChunkSize += chunkSize
+	}
+	return chunks, lengths
+
+}
+
+func getPreservedChunks(entries []*Entry, chunks []string, lengths []int) (preservedChunks []string, preservedChunkLengths []int) {
+	lastPreservedChunk := -1
+	for i := range entries {
+		if entries[i].Size < 0 {
+			continue
+		}
+		delta := entries[i].StartChunk - len(chunks)
+		if lastPreservedChunk != entries[i].StartChunk {
+			lastPreservedChunk = entries[i].StartChunk
+			preservedChunks = append(preservedChunks, chunks[entries[i].StartChunk])
+			preservedChunkLengths = append(preservedChunkLengths, lengths[entries[i].StartChunk])
+			delta++
+		}
+		for j := entries[i].StartChunk + 1; i <= entries[i].EndChunk; i++ {
+			preservedChunks = append(preservedChunks, chunks[j])
+			preservedChunkLengths = append(preservedChunkLengths, lengths[j])
+			lastPreservedChunk = j
+		}
+	}
+
+	return
+}
+
+func testEntryList(t *testing.T, numberOfEntries int, maximumInMemoryEntries int) {
+
+	entries := make([]*Entry, 0, numberOfEntries)
+	entrySizes := make([]int64, 0)
+
+	for i := 0; i < numberOfEntries; i++ {
+		entry:= CreateEntry(generateRandomString(16), -1, 0, 0700)
+		entries = append(entries, entry)
+		entrySizes = append(entrySizes, generateRandomFileSize())
+	}
+
+	totalFileSize := int64(0)
+	for _, size := range entrySizes {
+		totalFileSize += size
+	}
+
+	testDir := path.Join(os.TempDir(), "duplicacy_test")
+	os.RemoveAll(testDir)
+	os.MkdirAll(testDir, 0700)
+
+	os.MkdirAll(testDir + "/list1", 0700)
+	os.MkdirAll(testDir + "/list2", 0700)
+	os.MkdirAll(testDir + "/list3", 0700)
+	os.MkdirAll(testDir + "/list1", 0700)
+
+	// For the first entry list, all entries are new
+	entryList, _ := CreateEntryList("test", testDir + "/list1", maximumInMemoryEntries)
+	for _, entry := range entries {
+		entryList.AddEntry(entry)
+	}
+	uploadedChunks, uploadedChunksLengths := generateRandomChunks(totalFileSize)
+	for i, chunk := range uploadedChunks {
+		entryList.AddUploadedChunk(i, chunk, uploadedChunksLengths[i])
+	}
+
+	for i := range entryList.ModifiedEntries {
+		entryList.ModifiedEntries[i].Size = entrySizes[i]
+	}
+
+	totalEntries := 0
+	err := entryList.ReadEntries(func(entry *Entry) error {
+		totalEntries++
+		return nil
+	})
+
+	if err != nil {
+		t.Errorf("ReadEntries returned an error: %s", err)
+		return
+	}
+
+	if totalEntries != numberOfEntries {
+		t.Errorf("EntryList contains %d entries instead of %d", totalEntries, numberOfEntries)
+		return
+	}
+
+	// For the second entry list, half of the entries are new
+	for i := range entries {
+		if rand.Int() % 1 == 0 {
+			entries[i].Size = -1
+		} else {
+			entries[i].Size = entrySizes[i]
+		}
+	}
+
+	preservedChunks, preservedChunkLengths := getPreservedChunks(entries, uploadedChunks, uploadedChunksLengths)
+	entryList, _ = CreateEntryList("test", testDir + "/list2", maximumInMemoryEntries)
+	for _, entry := range entries {
+		entryList.AddEntry(entry)
+	}
+	for i, chunk := range preservedChunks {
+		entryList.AddPreservedChunk(chunk, preservedChunkLengths[i])
+	}
+
+	totalFileSize = 0
+	for i := range entryList.ModifiedEntries {
+		fileSize := generateRandomFileSize()		
+		entryList.ModifiedEntries[i].Size = fileSize
+		totalFileSize += fileSize
+	}
+
+	uploadedChunks, uploadedChunksLengths = generateRandomChunks(totalFileSize)
+	for i, chunk := range uploadedChunks {
+		entryList.AddUploadedChunk(i, chunk, uploadedChunksLengths[i])
+	}
+
+	totalEntries = 0
+	err = entryList.ReadEntries(func(entry *Entry) error {
+		totalEntries++
+		return nil
+	})
+
+	if err != nil {
+		t.Errorf("ReadEntries returned an error: %s", err)
+		return
+	}
+
+	if totalEntries != numberOfEntries {
+		t.Errorf("EntryList contains %d entries instead of %d", totalEntries, numberOfEntries)
+		return
+	}
+
+}
+
+
+func TestEntryList(t *testing.T) {
+	testEntryList(t, 1024, 1024)
+	testEntryList(t, 1024, 512)
+	testEntryList(t, 1024, 0)
+}

src/duplicacy_filefabricstorage.go

@@ -0,0 +1,618 @@
+// Copyright (c) Storage Made Easy. All rights reserved.
+// 
+// This storage backend is contributed by Storage Made Easy (https://storagemadeeasy.com/) to be used in
+// Duplicacy and its derivative works.
+//
+
+package duplicacy
+
+import (
+	"io"
+	"fmt"
+	"time"
+	"sync"
+	"bytes"
+	"errors"
+	"strings"
+	"net/url"
+	"net/http"
+	"math/rand"
+	"io/ioutil"
+	"encoding/xml"
+	"path/filepath"
+	"mime/multipart"
+)
+
+// The XML element representing a file returned by the File Fabric server
+type FileFabricFile struct {
+	XMLName     xml.Name
+	ID          string     `xml:"fi_id"`
+	Path        string     `xml:"path"`
+	Size        int64      `xml:"fi_size"`
+	Type        int        `xml:"fi_type"`
+}
+
+// The XML element representing a file list returned by the server
+type FileFabricFileList struct {
+	XMLName xml.Name `xml:"files"`
+	Files []FileFabricFile `xml:",any"`
+}
+
+type FileFabricStorage struct {
+	StorageBase
+
+	endpoint           string            // the server
+	authToken          string            // the authentication token
+	accessToken        string            // the access token (as returned by getTokenByAuthToken)
+	storageDir         string            // the path of the storage directory
+	storageDirID       string            // the id of 'storageDir'
+
+	client             *http.Client      // the default http client
+	threads            int               // number of threads
+	maxRetries         int               // maximum number of tries
+	directoryCache     map[string]string // stores ids for directories known to this backend
+	directoryCacheLock sync.Mutex        // lock for accessing directoryCache
+
+	isAuthorized       bool
+	testMode           bool
+}
+
+var (
+	errFileFabricAuthorizationFailure = errors.New("Authentication failure")
+	errFileFabricDirectoryExists = errors.New("Directory exists")
+)
+
+// The general server response
+type FileFabricResponse struct {
+	Status string `xml:"status"`
+	Message string `xml:"statusmessage"`
+}
+
+// Check the server response and return an error representing the error message it contains
+func checkFileFabricResponse(response FileFabricResponse, actionFormat string, actionArguments ...interface{}) error {
+
+	action := fmt.Sprintf(actionFormat, actionArguments...)
+	if response.Status == "ok" && response.Message == "Success" {
+		return nil
+	} else if response.Status == "error_data" {
+		if response.Message == "Folder with same name already exists." {
+			return errFileFabricDirectoryExists
+		}
+	}
+
+	return fmt.Errorf("Failed to %s (status: %s, message: %s)", action, response.Status, response.Message)
+}
+
+// Create a File Fabric storage backend
+func CreateFileFabricStorage(endpoint string, token string, storageDir string, threads int) (storage *FileFabricStorage, err error) {
+
+	if len(storageDir) > 0 && storageDir[len(storageDir)-1] != '/' {
+		storageDir += "/"
+	}
+
+	storage = &FileFabricStorage{
+
+		endpoint:       endpoint,
+		authToken:      token,
+		client:         http.DefaultClient,
+		threads:        threads,
+		directoryCache: make(map[string]string),
+		maxRetries:     12,
+	}
+
+	err = storage.getAccessToken()
+	if err != nil {
+		return nil, err
+	}
+
+	storageDirID, isDir, _, err := storage.getFileInfo(0, storageDir)
+	if err != nil {
+		return nil, err
+	}
+	if storageDirID == "" {
+		return nil, fmt.Errorf("Storage path %s does not exist", storageDir)
+	}
+	if !isDir {
+		return nil, fmt.Errorf("Storage path %s is not a directory", storageDir)
+	}
+	storage.storageDir = storageDir
+	storage.storageDirID = storageDirID
+
+	for _, dir := range []string{"snapshots", "chunks"} {
+		storage.CreateDirectory(0, dir)
+	}
+
+	storage.DerivedStorage = storage
+	storage.SetDefaultNestingLevels([]int{0}, 0)
+	return storage, nil
+}
+
+// Retrieve the access token using an auth token
+func (storage *FileFabricStorage) getAccessToken() (error) {
+
+    formData := url.Values { "authtoken": {storage.authToken},}
+	readCloser, _, _, err := storage.sendRequest(0, http.MethodPost, storage.getAPIURL("getTokenByAuthToken"), nil, formData)
+	if err != nil {
+		return err
+	}
+
+	defer readCloser.Close()
+	defer io.Copy(ioutil.Discard, readCloser)	
+
+    var output struct {
+		FileFabricResponse
+        Token string `xml:"token"`
+    }
+
+    err = xml.NewDecoder(readCloser).Decode(&output)
+    if err != nil {
+        return err
+    }
+
+	err = checkFileFabricResponse(output.FileFabricResponse, "request the access token")
+	if err != nil {
+		return err
+	}
+
+	storage.accessToken = output.Token
+    return nil
+}
+
+// Determine if we should retry based on the number of retries given by 'retry' and if so calculate the delay with exponential backoff
+func (storage *FileFabricStorage) shouldRetry(retry int, messageFormat string, messageArguments ...interface{}) bool {
+	message := fmt.Sprintf(messageFormat, messageArguments...)
+
+	if retry >= storage.maxRetries {
+		LOG_WARN("FILEFABRIC_REQUEST", "%s", message)
+		return false
+	}
+	backoff := 1 << uint(retry)
+	if backoff > 60 {
+		backoff = 60
+	}
+	delay := rand.Intn(backoff*500) + backoff*500
+	LOG_INFO("FILEFABRIC_RETRY", "%s; retrying after %.1f seconds", message, float32(delay) / 1000.0)
+	time.Sleep(time.Duration(delay) * time.Millisecond)
+	return true
+}
+
+// Send a request to the server
+func (storage *FileFabricStorage) sendRequest(threadIndex int, method string, requestURL string, requestHeaders map[string]string, input interface{}) ( io.ReadCloser, http.Header, int64, error) {
+
+	var response *http.Response
+
+	for retries := 0; ; retries++ {
+		var inputReader io.Reader
+
+		switch input.(type) {
+		case url.Values:
+			values := input.(url.Values)
+			inputReader = strings.NewReader(values.Encode())
+			if requestHeaders == nil {
+				requestHeaders = make(map[string]string)
+			}
+			requestHeaders["Content-Type"] = "application/x-www-form-urlencoded"
+		case *RateLimitedReader:
+			rateLimitedReader := input.(*RateLimitedReader)
+			rateLimitedReader.Reset()
+			inputReader = rateLimitedReader
+		default:
+			LOG_FATAL("FILEFABRIC_REQUEST", "Input type is not supported")
+			return nil, nil, 0, fmt.Errorf("Input type is not supported")
+		}
+
+		request, err := http.NewRequest(method, requestURL, inputReader)
+		if err != nil {
+			return nil, nil, 0, err
+		}
+
+		if requestHeaders != nil {
+			for key, value := range requestHeaders {
+				request.Header.Set(key, value)
+			}
+		}
+
+		if _, ok := input.(*RateLimitedReader); ok {
+			request.ContentLength = input.(*RateLimitedReader).Length()
+		}
+
+		response, err = storage.client.Do(request)
+		if err != nil {
+			if !storage.shouldRetry(retries, "[%d] %s %s returned an error: %v", threadIndex, method, requestURL, err) {
+				return nil, nil, 0, err
+			}
+			continue
+		}
+
+		if response.StatusCode < 300 {
+			return response.Body, response.Header, response.ContentLength, nil
+		}
+
+		defer response.Body.Close()
+		defer io.Copy(ioutil.Discard, response.Body)	
+
+		var output struct {
+			Status string `xml:"status"`
+			Message string `xml:"statusmessage"`
+		}
+	
+		err = xml.NewDecoder(response.Body).Decode(&output)
+		if err != nil {
+			if !storage.shouldRetry(retries, "[%d] %s %s returned an invalid response: %v", threadIndex, method, requestURL, err) {
+				return nil, nil, 0, err
+			}
+			continue
+		}
+
+		if !storage.shouldRetry(retries, "[%d] %s %s returned status: %s, message: %s", threadIndex, method, requestURL, output.Status, output.Message) {
+			return nil, nil, 0, err
+		}
+	}
+
+}
+
+func (storage *FileFabricStorage) getAPIURL(function string) string {
+	if storage.accessToken == "" {
+		return "https://" + storage.endpoint + "/api/*/" + function + "/"
+	} else {
+		return "https://" + storage.endpoint + "/api/" + storage.accessToken + "/" + function + "/"
+	}
+}
+
+// ListFiles return the list of files and subdirectories under 'dir'.  A subdirectories returned must have a trailing '/', with
+// a size of 0.  If 'dir' is 'snapshots', only subdirectories will be returned.  If 'dir' is 'snapshots/repository_id', then only
+// files will be returned.  If 'dir' is 'chunks', the implementation can return the list either recusively or non-recusively.
+func (storage *FileFabricStorage) ListFiles(threadIndex int, dir string) (files []string, sizes []int64, err error) {
+	if dir != "" && dir[len(dir)-1] != '/' {
+		dir += "/"
+	}
+
+	dirID, _, _, err := storage.getFileInfo(threadIndex, dir)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	if dirID == "" {
+		return nil, nil, nil
+	}
+
+	lastID := ""
+
+	for {
+		formData := url.Values { "marker": {lastID}, "limit": {"1000"}, "includefolders": {"n"}, "fi_pid" : {dirID}}
+		if dir == "snapshots/" {
+			formData["includefolders"] = []string{"y"}
+		}
+		if storage.testMode {
+			formData["limit"] = []string{"5"}
+		}
+
+		readCloser, _, _, err := storage.sendRequest(threadIndex, http.MethodPost, storage.getAPIURL("getListOfFiles"), nil, formData)
+		if err != nil {
+			return nil, nil, err
+		}
+
+		defer readCloser.Close()
+		defer io.Copy(ioutil.Discard, readCloser)	
+
+		var output struct {
+			FileFabricResponse
+			FileList FileFabricFileList `xml:"files"`
+			Truncated int `xml:"truncated"`
+		}
+
+		err = xml.NewDecoder(readCloser).Decode(&output)
+		if err != nil {
+			return nil, nil, err
+		}
+
+		err = checkFileFabricResponse(output.FileFabricResponse, "list the storage directory '%s'", dir)
+		if err != nil {
+			return nil, nil, err
+		}
+
+		if dir == "snapshots/" {
+			for _, file := range output.FileList.Files {
+				if file.Type == 1 {
+					files = append(files, file.Path + "/")
+				}
+				lastID = file.ID
+			}
+		} else {
+			for _, file := range output.FileList.Files {
+				if file.Type == 0 {
+					files = append(files, file.Path)
+					sizes = append(sizes, file.Size)
+				}
+				lastID = file.ID
+			}
+		}
+
+		if output.Truncated != 1 {
+			break
+		}
+	}
+	return files, sizes, nil
+}
+
+// getFileInfo returns the information about the file or directory at 'filePath'.
+func (storage *FileFabricStorage) getFileInfo(threadIndex int, filePath string) (fileID string, isDir bool, size int64, err error) {
+
+	formData := url.Values { "path" : {storage.storageDir + filePath}}
+
+	readCloser, _, _, err := storage.sendRequest(threadIndex, http.MethodPost, storage.getAPIURL("checkPathExists"), nil, formData)
+	if err != nil {
+		return "", false, 0, err
+	}
+
+	defer readCloser.Close()
+	defer io.Copy(ioutil.Discard, readCloser)	
+
+	var output struct {
+		FileFabricResponse
+		File FileFabricFile `xml:"file"`
+		Exists string `xml:"exists"`
+	}
+
+	err = xml.NewDecoder(readCloser).Decode(&output)
+	if err != nil {
+		return "", false, 0, err
+	}
+
+	err = checkFileFabricResponse(output.FileFabricResponse, "get the info on '%s'", filePath)
+	if err != nil {
+		return "", false, 0, err
+	}
+
+	if output.Exists != "y" {
+		return "", false, 0, nil
+	} else {
+		if output.File.Type == 1 {
+			for filePath != "" && filePath[len(filePath)-1] == '/' {
+				filePath = filePath[:len(filePath)-1]
+			}
+			
+			storage.directoryCacheLock.Lock()
+			storage.directoryCache[filePath] = output.File.ID
+			storage.directoryCacheLock.Unlock()
+		}
+		return output.File.ID, output.File.Type == 1, output.File.Size, nil
+	}
+}
+
+// GetFileInfo returns the information about the file or directory at 'filePath'.  This is a function required by the Storage interface.
+func (storage *FileFabricStorage) GetFileInfo(threadIndex int, filePath string) (exist bool, isDir bool, size int64, err error) {
+
+	fileID := ""
+	fileID, isDir, size, err = storage.getFileInfo(threadIndex, filePath)
+	return fileID != "", isDir, size, err
+}
+
+// DeleteFile deletes the file or directory at 'filePath'.
+func (storage *FileFabricStorage) DeleteFile(threadIndex int, filePath string) (err error) {
+
+	fileID, _, _, _ := storage.getFileInfo(threadIndex, filePath)
+	if fileID == "" {
+		return nil
+	}
+
+	formData := url.Values { "fi_id" : {fileID}}
+
+	readCloser, _, _, err := storage.sendRequest(threadIndex, http.MethodPost, storage.getAPIURL("doDeleteFile"), nil, formData)
+	if err != nil {
+		return err
+	}
+
+	defer readCloser.Close()
+	defer io.Copy(ioutil.Discard, readCloser)	
+
+	var output FileFabricResponse
+
+	err = xml.NewDecoder(readCloser).Decode(&output)
+	if err != nil {
+		return err
+	}
+
+	err = checkFileFabricResponse(output, "delete file '%s'", filePath)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// MoveFile renames the file.
+func (storage *FileFabricStorage) MoveFile(threadIndex int, from string, to string) (err error) {
+	fileID, _, _, _ := storage.getFileInfo(threadIndex, from)
+	if fileID == "" {
+		return nil
+	}
+
+	formData := url.Values { "fi_id" : {fileID}, "fi_name": {filepath.Base(to)},}
+
+	readCloser, _, _, err := storage.sendRequest(threadIndex, http.MethodPost, storage.getAPIURL("doRenameFile"), nil, formData)
+	if err != nil {
+		return err
+	}
+
+	defer readCloser.Close()
+	defer io.Copy(ioutil.Discard, readCloser)	
+
+	var output FileFabricResponse
+
+	err = xml.NewDecoder(readCloser).Decode(&output)
+	if err != nil {
+		return err
+	}
+
+	err = checkFileFabricResponse(output, "rename file '%s' to '%s'", from, to)
+	if err != nil {
+		return err
+	}
+	
+	return nil
+}
+
+// createParentDirectory creates the parent directory if it doesn't exist in the cache.
+func (storage *FileFabricStorage) createParentDirectory(threadIndex int, dir string) (parentID string, err error) {
+
+	found := strings.LastIndex(dir, "/")
+	if found == -1 {
+		return storage.storageDirID, nil
+	}
+	parent := dir[:found]
+
+	storage.directoryCacheLock.Lock()
+	parentID = storage.directoryCache[parent]
+	storage.directoryCacheLock.Unlock()
+
+	if parentID != "" {
+		return parentID, nil
+	}
+
+	parentID, err = storage.createDirectory(threadIndex, parent)
+	if err != nil {
+		if err == errFileFabricDirectoryExists {
+		    var isDir bool
+			parentID, isDir, _, err = storage.getFileInfo(threadIndex, parent)
+			if err != nil {
+				return "", err
+			}
+			if isDir == false {
+				return "", fmt.Errorf("'%s' in the storage is a file", parent)
+			}
+			storage.directoryCacheLock.Lock()
+			storage.directoryCache[parent] = parentID
+			storage.directoryCacheLock.Unlock()
+			return parentID, nil
+		} else {
+			return "", err
+		}
+	}
+	return parentID, nil
+}
+
+// createDirectory creates a new directory.
+func (storage *FileFabricStorage) createDirectory(threadIndex int, dir string) (dirID string, err error) {
+	for dir != "" && dir[len(dir)-1] == '/' {
+		dir = dir[:len(dir)-1]
+	}
+
+	parentID, err := storage.createParentDirectory(threadIndex, dir)
+	if err != nil {
+		return "", err
+	}
+
+	formData := url.Values { "fi_name": {filepath.Base(dir)}, "fi_pid" : {parentID}}
+
+	readCloser, _, _, err := storage.sendRequest(threadIndex, http.MethodPost, storage.getAPIURL("doCreateNewFolder"), nil, formData)
+	if err != nil {
+		return "", err
+	}
+
+	defer readCloser.Close()
+	defer io.Copy(ioutil.Discard, readCloser)	
+
+	var output struct {
+		FileFabricResponse
+		File FileFabricFile `xml:"file"`
+	}
+
+	err = xml.NewDecoder(readCloser).Decode(&output)
+	if err != nil {
+		return "", err
+	}
+
+	err = checkFileFabricResponse(output.FileFabricResponse, "create directory '%s'", dir)
+	if err != nil {
+		return "", err
+	}
+
+	storage.directoryCacheLock.Lock()
+	storage.directoryCache[dir] = output.File.ID
+	storage.directoryCacheLock.Unlock()
+
+	return output.File.ID, nil
+}
+
+func (storage *FileFabricStorage) CreateDirectory(threadIndex int, dir string) (err error) {
+	_, err = storage.createDirectory(threadIndex, dir)
+	if err == errFileFabricDirectoryExists {
+		return nil
+	}
+	return err
+}
+
+// DownloadFile reads the file at 'filePath' into the chunk.
+func (storage *FileFabricStorage) DownloadFile(threadIndex int, filePath string, chunk *Chunk) (err error) {
+	formData := url.Values { "fi_id" : {storage.storageDir + filePath}}
+
+	readCloser, _, _, err := storage.sendRequest(threadIndex, http.MethodPost, storage.getAPIURL("getFile"), nil, formData)
+	if err != nil {
+		return err
+	}
+
+	defer readCloser.Close()
+	defer io.Copy(ioutil.Discard, readCloser)	
+	_, err = RateLimitedCopy(chunk, readCloser, storage.DownloadRateLimit/storage.threads)
+	return err
+}
+
+// UploadFile writes 'content' to the file at 'filePath'.
+func (storage *FileFabricStorage) UploadFile(threadIndex int, filePath string, content []byte) (err error) {
+
+	parentID, err := storage.createParentDirectory(threadIndex, filePath)
+	if err != nil {
+		return err
+	}
+
+	fileName := filepath.Base(filePath)
+    requestBody := &bytes.Buffer{}
+    writer := multipart.NewWriter(requestBody)
+    part, _ := writer.CreateFormFile("file_1", fileName)
+    part.Write(content)
+
+    writer.WriteField("file_name1", fileName)
+	writer.WriteField("fi_pid", parentID)
+	writer.WriteField("fi_structtype", "g")
+    writer.Close()
+
+	headers := make(map[string]string)
+	headers["Content-Type"] = writer.FormDataContentType()
+
+	rateLimitedReader := CreateRateLimitedReader(requestBody.Bytes(), storage.UploadRateLimit/storage.threads)
+	readCloser, _, _, err := storage.sendRequest(threadIndex, http.MethodPost, storage.getAPIURL("doUploadFiles"), headers, rateLimitedReader)
+
+	defer readCloser.Close()
+	defer io.Copy(ioutil.Discard, readCloser)	
+
+	var output FileFabricResponse
+
+	err = xml.NewDecoder(readCloser).Decode(&output)
+	if err != nil {
+		return err
+	}
+
+	err = checkFileFabricResponse(output, "upload file '%s'", filePath)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// If a local snapshot cache is needed for the storage to avoid downloading/uploading chunks too often when
+// managing snapshots.
+func (storage *FileFabricStorage) IsCacheNeeded() bool { return true }
+
+// If the 'MoveFile' method is implemented.
+func (storage *FileFabricStorage) IsMoveFileImplemented() bool { return true }
+
+// If the storage can guarantee strong consistency.
+func (storage *FileFabricStorage) IsStrongConsistent() bool { return false }
+
+// If the storage supports fast listing of files names.
+func (storage *FileFabricStorage) IsFastListing() bool { return false }
+
+// Enable the test mode.
+func (storage *FileFabricStorage) EnableTestMode() { storage.testMode = true }

src/duplicacy_filereader.go

@@ -21,7 +21,7 @@ type FileReader struct {
 }
 
 // CreateFileReader creates a file reader.
-func CreateFileReader(top string, files[] *Entry) (*FileReader) {
+func CreateFileReader(top string, files []*Entry) *FileReader {
 
 	reader := &FileReader{
 		top:          top,
@@ -34,7 +34,7 @@ func CreateFileReader(top string, files[] *Entry) (*FileReader) {
 	return reader
 }
 
-// NextFile switchs to the next file in the file reader.
+// NextFile switches to the next file in the file reader.
 func (reader *FileReader) NextFile() bool {
 
 	if reader.CurrentFile != nil {
@@ -68,7 +68,3 @@ func (reader *FileReader) NextFile() bool{
 	reader.CurrentFile = nil
 	return false
 }
-
-
-
-

src/duplicacy_filestorage.go

@@ -5,34 +5,41 @@
 package duplicacy
 
 import (
-    "os"
 	"fmt"
-    "path"
 	"io"
 	"io/ioutil"
-    "time"
 	"math/rand"
+	"os"
+	"path"
+	"strings"
+	"syscall"
+	"time"
 )
 
 // FileStorage is a local on-disk file storage implementing the Storage interface.
 type FileStorage struct {
-    RateLimitedStorage
+	StorageBase
 
+	isCacheNeeded   bool // Network storages require caching
 	storageDir      string
 	numberOfThreads int
 }
 
 // CreateFileStorage creates a file storage.
-func CreateFileStorage(storageDir string, threads int) (storage *FileStorage, err error) {
+func CreateFileStorage(storageDir string, isCacheNeeded bool, threads int) (storage *FileStorage, err error) {
 
 	var stat os.FileInfo
 
 	stat, err = os.Stat(storageDir)
+	if err != nil {
 		if os.IsNotExist(err) {
 			err = os.MkdirAll(storageDir, 0744)
 			if err != nil {
 				return nil, err
 			}
+		} else {
+			return nil, err
+		}
 	} else {
 		if !stat.IsDir() {
 			return nil, fmt.Errorf("The storage path %s is a file", storageDir)
@@ -45,12 +52,15 @@ func CreateFileStorage(storageDir string, threads int) (storage *FileStorage, er
 
 	storage = &FileStorage{
 		storageDir:      storageDir,
+		isCacheNeeded:   isCacheNeeded,
 		numberOfThreads: threads,
 	}
 
 	// Random number fo generating the temporary chunk file suffix.
 	rand.Seed(time.Now().UnixNano())
 
+	storage.DerivedStorage = storage
+	storage.SetDefaultNestingLevels([]int{2, 3}, 2)
 	return storage, nil
 }
 
@@ -69,7 +79,7 @@ func (storage *FileStorage) ListFiles(threadIndex int, dir string) (files []stri
 
 	for _, f := range list {
 		name := f.Name()
-        if f.IsDir() && name[len(name) - 1] != '/' {
+		if (f.IsDir() || f.Mode() & os.ModeSymlink != 0) && name[len(name)-1] != '/' {
 			name += "/"
 		}
 		files = append(files, name)
@@ -118,68 +128,6 @@ func (storage *FileStorage) GetFileInfo(threadIndex int, filePath string) (exist
 	return true, stat.IsDir(), stat.Size(), nil
 }
 
-// FindChunk finds the chunk with the specified id.  If 'isFossil' is true, it will search for chunk files with the
-// suffix '.fsl'.
-func (storage *FileStorage) FindChunk(threadIndex int, chunkID string, isFossil bool) (filePath string, exist bool, size int64, err error) {
-     dir := path.Join(storage.storageDir, "chunks")
-
-    suffix := ""
-    if isFossil {
-        suffix = ".fsl"
-    }
-
-    // The minimum level of directories to dive into before searching for the chunk file.
-    minimumLevel := 2
-
-    for level := 0; level * 2 < len(chunkID); level ++ {
-        if level >= minimumLevel {
-            filePath = path.Join(dir, chunkID[2 * level:]) + suffix
-            if stat, err := os.Stat(filePath); err == nil && !stat.IsDir() {
-                return filePath[len(storage.storageDir) + 1:], true, stat.Size(), nil
-            } else if err == nil && stat.IsDir() {
-                return filePath[len(storage.storageDir) + 1:], true, 0, fmt.Errorf("The path %s is a directory", filePath)
-            }
-        }
-
-        // Find the subdirectory the chunk file may reside.
-        subDir := path.Join(dir, chunkID[2 * level: 2 * level + 2])
-        stat, err := os.Stat(subDir)
-        if err == nil && stat.IsDir() {
-            dir = subDir
-            continue
-        }
-
-        if level < minimumLevel {
-            // Create the subdirectory if it doesn't exist.
-
-            if err == nil && !stat.IsDir() {
-                return "", false, 0, fmt.Errorf("The path %s is not a directory", subDir)
-            }
-
-            err = os.Mkdir(subDir, 0744)
-            if err != nil {
-                // The directory may have been created by other threads so check it again.
-                stat, _ := os.Stat(subDir)
-                if stat == nil || !stat.IsDir() {
-                    return "", false, 0, err
-                }
-            }
-
-            dir = subDir
-            continue
-        }
-
-        // The chunk must be under this subdirectory but it doesn't exist.
-        return path.Join(dir, chunkID[2 * level:])[len(storage.storageDir) + 1:] + suffix, false, 0, nil
-
-    }
-
-    LOG_FATAL("CHUNK_FIND", "Chunk %s is still not found after having searched a maximum level of directories",
-              chunkID)
-    return "", false, 0, nil
-
-}
-
 // DownloadFile reads the file at 'filePath' into the chunk.
 func (storage *FileStorage) DownloadFile(threadIndex int, filePath string, chunk *Chunk) (err error) {
 
@@ -203,6 +151,26 @@ func (storage *FileStorage) UploadFile(threadIndex int, filePath string, content
 
 	fullPath := path.Join(storage.storageDir, filePath)
 
+	if len(strings.Split(filePath, "/")) > 2 {
+		dir := path.Dir(fullPath)
+		// Use Lstat() instead of Stat() since 1) Stat() doesn't work for deduplicated disks on Windows and 2) there isn't
+		// really a need to follow the link if filePath is a link.
+		stat, err := os.Lstat(dir)
+		if err != nil {
+			if !os.IsNotExist(err) {
+				return err
+			}
+			err = os.MkdirAll(dir, 0744)
+			if err != nil {
+				return err
+			}
+		} else {
+			if !stat.IsDir() && stat.Mode() & os.ModeSymlink == 0 {
+				return fmt.Errorf("The path %s is not a directory or symlink", dir)
+			}
+		}
+	}
+
 	letters := "abcdefghijklmnopqrstuvwxyz"
 	suffix := make([]byte, 8)
 	for i := range suffix {
@@ -223,7 +191,19 @@ func (storage *FileStorage) UploadFile(threadIndex int, filePath string, content
 		return err
 	}
 
-    file.Close()
+	if err = file.Sync(); err != nil {
+		pathErr, ok := err.(*os.PathError)
+		isNotSupported := ok && pathErr.Op == "sync" && pathErr.Err == syscall.ENOTSUP
+		if !isNotSupported {
+			_ = file.Close()
+			return err
+		}
+	}
+
+	err = file.Close()
+	if err != nil {
+		return err
+	}
 
 	err = os.Rename(temporaryFile, fullPath)
 	if err != nil {
@@ -241,16 +221,16 @@ func (storage *FileStorage) UploadFile(threadIndex int, filePath string, content
 
 // If a local snapshot cache is needed for the storage to avoid downloading/uploading chunks too often when
 // managing snapshots.
-func (storage *FileStorage) IsCacheNeeded () (bool) { return false }
+func (storage *FileStorage) IsCacheNeeded() bool { return storage.isCacheNeeded }
 
 // If the 'MoveFile' method is implemented.
-func (storage *FileStorage) IsMoveFileImplemented() (bool) { return true }
+func (storage *FileStorage) IsMoveFileImplemented() bool { return true }
 
 // If the storage can guarantee strong consistency.
-func (storage *FileStorage) IsStrongConsistent() (bool) { return true }
+func (storage *FileStorage) IsStrongConsistent() bool { return true }
 
 // If the storage supports fast listing of files names.
-func (storage *FileStorage) IsFastListing() (bool) { return false }
+func (storage *FileStorage) IsFastListing() bool { return false }
 
 // Enable the test mode.
 func (storage *FileStorage) EnableTestMode() {}

src/duplicacy_gcdstorage.go

@@ -5,37 +5,48 @@
 package duplicacy
 
 import (
-    "io"
+	"encoding/json"
 	"fmt"
-    "net"
-    "path"
-    "time"
-    "sync"
-    "strings"
-    "net/http"
-    "net/url"
+	"io"
 	"io/ioutil"
 	"math/rand"
-    "encoding/json"
+	"net"
+	"net/http"
+	"net/url"
+	"path"
+	"strings"
+	"sync"
+	"time"
 
 	"golang.org/x/net/context"
 	"golang.org/x/oauth2"
+	"golang.org/x/oauth2/google"
 	"google.golang.org/api/drive/v3"
 	"google.golang.org/api/googleapi"
+	"google.golang.org/api/option"
+)
+
+var (
+	GCDFileMimeType      = "application/octet-stream"
+	GCDDirectoryMimeType = "application/vnd.google-apps.folder"
+	GCDUserDrive         = "root"
 )
 
 type GCDStorage struct {
-    RateLimitedStorage
+	StorageBase
 
 	service     *drive.Service
-    idCache map[string]string
-    idCacheLock *sync.Mutex
-    backoff int
+	idCache     map[string]string // only directories are saved in this cache
+	idCacheLock sync.Mutex
+	backoffs    []int // desired backoff time in seconds for each thread
+	attempts    []int // number of failed attempts since last success for each thread
+	driveID     string // the ID of the shared drive or 'root' (GCDUserDrive) if the user's drive
+	spaces      string // 'appDataFolder' if scope is drive.appdata; 'drive' otherwise
 
+	createDirectoryLock sync.Mutex
 	isConnected         bool
 	numberOfThreads     int
 	TestMode            bool
-
 }
 
 type GCDConfig struct {
@@ -45,12 +56,19 @@ type GCDConfig struct {
 	Token        oauth2.Token    `json:"token"`
 }
 
-func (storage *GCDStorage) shouldRetry(err error) (bool, error) {
+func (storage *GCDStorage) shouldRetry(threadIndex int, err error) (bool, error) {
 
+	const MAX_ATTEMPTS = 15
+
+	maximumBackoff := 64
+	if maximumBackoff < storage.numberOfThreads {
+		maximumBackoff = storage.numberOfThreads
+	}
 	retry := false
 	message := ""
 	if err == nil {
-        storage.backoff = 1
+		storage.backoffs[threadIndex] = 1
+		storage.attempts[threadIndex] = 0
 		return false, nil
 	} else if e, ok := err.(*googleapi.Error); ok {
 		if 500 <= e.Code && e.Code < 600 {
@@ -63,7 +81,15 @@ func (storage *GCDStorage) shouldRetry(err error) (bool, error) {
 			retry = true
 		} else if e.Code == 403 {
 			// User Rate Limit Exceeded
-            message = "User Rate Limit Exceeded"
+			message = e.Message
+			retry = true
+		} else if e.Code == 408 {
+			// Request timeout
+			message = e.Message
+			retry = true
+		} else if e.Code == 400 && strings.Contains(e.Message, "failedPrecondition") {
+			// Daily quota exceeded
+			message = e.Message
 			retry = true
 		} else if e.Code == 401 {
 			// Only retry on authorization error when storage has been connected before
@@ -84,19 +110,37 @@ func (storage *GCDStorage) shouldRetry(err error) (bool, error) {
 		retry = err.Temporary()
 	}
 
-    if !retry || storage.backoff >= 256{
-        storage.backoff = 1
+	if !retry {
 		return false, err
 	}
 
-    delay := float32(storage.backoff) * rand.Float32()
-    LOG_DEBUG("GCD_RETRY", "%s; retrying after %.2f seconds", message, delay)
-    time.Sleep(time.Duration(float32(storage.backoff) * float32(time.Second)))
-    storage.backoff *= 2
+	if storage.attempts[threadIndex] >= MAX_ATTEMPTS {
+		LOG_INFO("GCD_RETRY", "[%d] Maximum number of retries reached (backoff: %d, attempts: %d)",
+			threadIndex, storage.backoffs[threadIndex], storage.attempts[threadIndex])
+		storage.backoffs[threadIndex] = 1
+		storage.attempts[threadIndex] = 0
+		return false, err
+	}
+
+	if storage.backoffs[threadIndex] < maximumBackoff {
+		storage.backoffs[threadIndex] *= 2
+	}
+	if storage.backoffs[threadIndex] > maximumBackoff {
+		storage.backoffs[threadIndex] = maximumBackoff
+	}
+	storage.attempts[threadIndex] += 1
+	delay := float64(storage.backoffs[threadIndex]) * rand.Float64() * 2
+	LOG_DEBUG("GCD_RETRY", "[%d] %s; retrying after %.2f seconds (backoff: %d, attempts: %d)",
+		threadIndex, message, delay, storage.backoffs[threadIndex], storage.attempts[threadIndex])
+	time.Sleep(time.Duration(delay * float64(time.Second)))
+
 	return true, nil
 }
 
-func (storage *GCDStorage) convertFilePath(filePath string) (string) {
+// convertFilePath converts the path for a fossil in the form of 'chunks/id.fsl' to 'fossils/id'.  This is because
+// GCD doesn't support file renaming. Instead, it only allows one file to be moved from one directory to another.
+// By adding a layer of path conversion we're pretending that we can rename between 'chunks/id' and 'chunks/id.fsl'
+func (storage *GCDStorage) convertFilePath(filePath string) string {
 	if strings.HasPrefix(filePath, "chunks/") && strings.HasSuffix(filePath, ".fsl") {
 		return "fossils/" + filePath[len("chunks/"):len(filePath)-len(".fsl")]
 	}
@@ -129,7 +173,7 @@ func (storage *GCDStorage) deletePathID(path string) {
 	storage.idCacheLock.Unlock()
 }
 
-func (storage *GCDStorage) listFiles(parentID string, listFiles bool) ([]*drive.File, error) {
+func (storage *GCDStorage) listFiles(threadIndex int, parentID string, listFiles bool, listDirectories bool) ([]*drive.File, error) {
 
 	if parentID == "" {
 		return nil, fmt.Errorf("No parent ID provided")
@@ -139,11 +183,11 @@ func (storage *GCDStorage) listFiles(parentID string, listFiles bool) ([]*drive.
 
 	startToken := ""
 
-    query := "'" + parentID + "' in parents and "
-    if listFiles {
-        query += "mimeType != 'application/vnd.google-apps.folder'"
-    } else {
-        query += "mimeType = 'application/vnd.google-apps.folder'"
+	query := "'" + parentID + "' in parents and trashed = false "
+	if listFiles && !listDirectories {
+		query += "and mimeType != 'application/vnd.google-apps.folder'"
+	} else if !listFiles && !listDirectories {
+		query += "and mimeType = 'application/vnd.google-apps.folder'"
 	}
 
 	maxCount := int64(1000)
@@ -156,8 +200,12 @@ func (storage *GCDStorage) listFiles(parentID string, listFiles bool) ([]*drive.
 		var err error
 
 		for {
-            fileList, err = storage.service.Files.List().Q(query).Fields("nextPageToken", "files(name, mimeType, id, size)").PageToken(startToken).PageSize(maxCount).Do()
-            if retry, e := storage.shouldRetry(err); e == nil && !retry {
+			q := storage.service.Files.List().Q(query).Fields("nextPageToken", "files(name, mimeType, id, size)").PageToken(startToken).PageSize(maxCount).Spaces(storage.spaces)
+			if storage.driveID != GCDUserDrive {
+				q = q.DriveId(storage.driveID).IncludeItemsFromAllDrives(true).Corpora("drive").SupportsAllDrives(true)
+			}
+			fileList, err = q.Do()
+			if retry, e := storage.shouldRetry(threadIndex, err); e == nil && !retry {
 				break
 			} else if retry {
 				continue
@@ -174,20 +222,23 @@ func (storage *GCDStorage) listFiles(parentID string, listFiles bool) ([]*drive.
 		}
 	}
 
-
 	return files, nil
 }
 
-func (storage *GCDStorage) listByName(parentID string, name string) (string, bool, int64, error) {
+func (storage *GCDStorage) listByName(threadIndex int, parentID string, name string) (string, bool, int64, error) {
 
 	var fileList *drive.FileList
 	var err error
 
 	for {
-        query := "name = '" + name + "' and '" + parentID + "' in parents"
-        fileList, err = storage.service.Files.List().Q(query).Fields("files(name, mimeType, id, size)").Do()
+		query := "name = '" + name + "' and '" + parentID + "' in parents and trashed = false "
+		q := storage.service.Files.List().Q(query).Fields("files(name, mimeType, id, size)").Spaces(storage.spaces)
+		if storage.driveID != GCDUserDrive {
+			q = q.DriveId(storage.driveID).IncludeItemsFromAllDrives(true).Corpora("drive").SupportsAllDrives(true)
+		}
+		fileList, err = q.Do()
 
-        if retry, e := storage.shouldRetry(err); e == nil && !retry {
+		if retry, e := storage.shouldRetry(threadIndex, err); e == nil && !retry {
 			break
 		} else if retry {
 			continue
@@ -202,57 +253,140 @@ func (storage *GCDStorage) listByName(parentID string, name string) (string, boo
 
 	file := fileList.Files[0]
 
-    return file.Id, file.MimeType == "application/vnd.google-apps.folder", file.Size, nil
+	return file.Id, file.MimeType == GCDDirectoryMimeType, file.Size, nil
 }
 
-func (storage *GCDStorage) getIDFromPath(path string) (string, error) {
+// Returns the id of the shared folder with the given name if it exists
+func (storage *GCDStorage) findSharedFolder(threadIndex int, name string) (string, error) {
 
-    fileID := "root"
+	query := "name = '" + name + "' and sharedWithMe and trashed = false and mimeType = 'application/vnd.google-apps.folder'"
+	q := storage.service.Files.List().Q(query).Fields("files(name, mimeType, id, size)").Spaces(storage.spaces)
+	if storage.driveID != GCDUserDrive {
+		q = q.DriveId(storage.driveID).IncludeItemsFromAllDrives(true).Corpora("drive").SupportsAllDrives(true)
+	}
+
+	fileList, err := q.Do()
+	if err != nil {
+		return "", err
+	}
+
+	if len(fileList.Files) == 0 {
+		return "", nil
+	}
+
+	file := fileList.Files[0]
+
+	return file.Id, nil
+}
+
+// getIDFromPath returns the id of the given path.  If 'createDirectories' is true, create the given path and all its
+// parent directories if they don't exist.  Note that if 'createDirectories' is false, it may return an empty 'fileID'
+// if the file doesn't exist.
+func (storage *GCDStorage) getIDFromPath(threadIndex int, filePath string, createDirectories bool) (string, error) {
+
+	if fileID, ok := storage.findPathID(filePath); ok {
+		return fileID, nil
+	}
+
+	fileID := storage.driveID
 
 	if rootID, ok := storage.findPathID(""); ok {
 		fileID = rootID
 	}
 
-    names := strings.Split(path, "/")
+	names := strings.Split(filePath, "/")
 	current := ""
 	for i, name := range names {
-
-        if len(current) == 0 {
-            current = name
-        } else {
-            current = current + "/" + name
-        }
-
+		// Find the intermediate directory in the cache first.
+		current = path.Join(current, name)
 		currentID, ok := storage.findPathID(current)
 		if ok {
 			fileID = currentID
 			continue
 		}
 
+		// Check if the directory exists.
 		var err error
 		var isDir bool
-        fileID, isDir, _, err = storage.listByName(fileID, name)
+		fileID, isDir, _, err = storage.listByName(threadIndex, fileID, name)
 		if err != nil {
 			return "", err
 		}
 		if fileID == "" {
-            return "", fmt.Errorf("Path %s doesn't exist", path)
+			if !createDirectories {
+				return "", nil
+			}
+
+			// Only one thread can create the directory at a time -- GCD allows multiple directories
+			// to have the same name but different ids.
+			storage.createDirectoryLock.Lock()
+			err = storage.CreateDirectory(threadIndex, current)
+			storage.createDirectoryLock.Unlock()
+
+			if err != nil {
+				return "", fmt.Errorf("Failed to create directory '%s': %v", current, err)
+			}
+			currentID, ok = storage.findPathID(current)
+			if !ok {
+				return "", fmt.Errorf("Directory '%s' created by id not found", current)
+			}
+			fileID = currentID
+			continue
+		} else if isDir {
+			storage.savePathID(current, fileID)
 		}
 		if i != len(names)-1 && !isDir {
-            return "", fmt.Errorf("Invalid path %s", path)
+			return "", fmt.Errorf("Path '%s' is not a directory", current)
 		}
 	}
 	return fileID, nil
 }
 
 // CreateGCDStorage creates a GCD storage object.
-func CreateGCDStorage(tokenFile string, storagePath string, threads int) (storage *GCDStorage, err error) {
+func CreateGCDStorage(tokenFile string, driveID string, storagePath string, threads int) (storage *GCDStorage, err error) {
+
+	ctx := context.Background()
 
 	description, err := ioutil.ReadFile(tokenFile)
 	if err != nil {
 		return nil, err
 	}
 
+	var object map[string]interface{}
+
+	err = json.Unmarshal(description, &object)
+	if err != nil {
+		return nil, err
+	}
+
+	isServiceAccount := false
+	if value, ok := object["type"]; ok {
+		if authType, ok := value.(string); ok && authType == "service_account" {
+			isServiceAccount = true
+		}
+	}
+
+	var tokenSource oauth2.TokenSource
+
+	scope := drive.DriveScope
+
+	if isServiceAccount {
+
+		if newScope, ok := object["scope"]; ok {
+			scope = newScope.(string)
+		}
+
+		config, err := google.JWTConfigFromJSON(description, scope)
+		if err != nil {
+			return nil, err
+		}
+
+		if subject, ok := object["subject"]; ok {
+		    config.Subject = subject.(string)
+		}
+
+		tokenSource = config.TokenSource(ctx)
+	} else {
 		gcdConfig := &GCDConfig{}
 		if err := json.Unmarshal(description, gcdConfig); err != nil {
 			return nil, err
@@ -263,30 +397,82 @@ func CreateGCDStorage(tokenFile string, storagePath string, threads int) (storag
 			ClientSecret: gcdConfig.ClientSecret,
 			Endpoint:     gcdConfig.Endpoint,
 		}
+		tokenSource = config.TokenSource(ctx, &gcdConfig.Token)
+	}
 
-    authClient := config.Client(context.Background(), &gcdConfig.Token)
-
-    service, err := drive.New(authClient)
+	service, err := drive.NewService(ctx, option.WithTokenSource(tokenSource))
 	if err != nil {
 		return nil, err
 	}
 
+	if len(driveID) == 0 {
+		driveID = GCDUserDrive
+	} else {
+		driveList, err := drive.NewTeamdrivesService(service).List().Do()
+		if err != nil {
+			return nil, fmt.Errorf("Failed to look up the drive id: %v", err)
+		}
+
+		found := false
+		for _, teamDrive := range driveList.TeamDrives {
+			if teamDrive.Id == driveID || teamDrive.Name == driveID {
+				driveID = teamDrive.Id
+				found = true
+				break
+			}
+		}
+
+		if !found {
+			return nil, fmt.Errorf("%s is not the id or name of a shared drive", driveID)
+		}
+	}
+
 	storage = &GCDStorage{
 		service:         service,
 		numberOfThreads: threads,
 		idCache:         make(map[string]string),
-        idCacheLock: &sync.Mutex{},
+		backoffs:        make([]int, threads),
+		attempts:        make([]int, threads),
+		driveID:         driveID,
+		spaces:          "drive",
 	}
 
-    storagePathID, err := storage.getIDFromPath(storagePath)
+	for i := range storage.backoffs {
+		storage.backoffs[i] = 1
+		storage.attempts[i] = 0
+	}
+
+
+	if scope == drive.DriveAppdataScope {
+		storage.spaces = "appDataFolder"
+		storage.savePathID("", "appDataFolder")
+	} else {
+		storage.savePathID("", driveID)
+	}
+
+	storagePathID := ""
+
+	// When using service acount, check if storagePath is a shared folder which takes priority over regular folders.
+	if isServiceAccount && !strings.Contains(storagePath, "/") {
+		storagePathID, err = storage.findSharedFolder(0, storagePath)
+		if err != nil {
+			LOG_WARN("GCD_STORAGE", "Failed to check if %s is a shared folder: %v", storagePath, err)
+		}
+	}
+
+	if storagePathID == "" {
+		storagePathID, err = storage.getIDFromPath(0, storagePath, true)
 		if err != nil {
 			return nil, err
 		}
+	}
 
+	// Reset the id cache and start with 'storagePathID' as the root
+	storage.idCache = make(map[string]string)
 	storage.idCache[""] = storagePathID
 
 	for _, dir := range []string{"chunks", "snapshots", "fossils"} {
-        dirID, isDir, _, err := storage.listByName(storagePathID, dir)
+		dirID, isDir, _, err := storage.listByName(0, storagePathID, dir)
 		if err != nil {
 			return nil, err
 		}
@@ -296,7 +482,7 @@ func CreateGCDStorage(tokenFile string, storagePath string, threads int) (storag
 				return nil, err
 			}
 		} else if !isDir {
-            return nil, fmt.Errorf("%s/%s is not a directory", storagePath + "/" + dir)
+			return nil, fmt.Errorf("%s/%s is not a directory", storagePath, dir)
 		} else {
 			storage.idCache[dir] = dirID
 		}
@@ -304,8 +490,9 @@ func CreateGCDStorage(tokenFile string, storagePath string, threads int) (storag
 
 	storage.isConnected = true
 
+	storage.DerivedStorage = storage
+	storage.SetDefaultNestingLevels([]int{0}, 0)
 	return storage, nil
-
 }
 
 // ListFiles return the list of files and subdirectories under 'dir' (non-recursively)
@@ -316,7 +503,7 @@ func (storage *GCDStorage) ListFiles(threadIndex int, dir string) ([]string, []i
 
 	if dir == "snapshots" {
 
-        files, err := storage.listFiles(storage.getPathID(dir), false)
+		files, err := storage.listFiles(threadIndex, storage.getPathID(dir), false, true)
 		if err != nil {
 			return nil, nil, err
 		}
@@ -328,13 +515,16 @@ func (storage *GCDStorage) ListFiles(threadIndex int, dir string) ([]string, []i
 			subDirs = append(subDirs, file.Name+"/")
 		}
 		return subDirs, nil, nil
-    } else if strings.HasPrefix(dir, "snapshots/") {
-        pathID, err := storage.getIDFromPath(dir)
+	} else if strings.HasPrefix(dir, "snapshots/") || strings.HasPrefix(dir, "benchmark") {
+		pathID, err := storage.getIDFromPath(threadIndex, dir, false)
 		if err != nil {
 			return nil, nil, err
 		}
+		if pathID == "" {
+			return nil, nil, fmt.Errorf("Path '%s' does not exist", dir)
+		}
 
-        entries, err := storage.listFiles(pathID, true)
+		entries, err := storage.listFiles(threadIndex, pathID, true, false)
 		if err != nil {
 			return nil, nil, err
 		}
@@ -342,31 +532,80 @@ func (storage *GCDStorage) ListFiles(threadIndex int, dir string) ([]string, []i
 		files := []string{}
 
 		for _, entry := range entries {
-            storage.savePathID(dir + "/" + entry.Name, entry.Id)
 			files = append(files, entry.Name)
 		}
 		return files, nil, nil
 	} else {
+		lock := sync.Mutex {}
+		allFiles := []string{}
+		allSizes := []int64{}
+
+		errorChannel := make(chan error)
+		directoryChannel := make(chan string)
+		activeWorkers := 0
+
+		parents := []string{"chunks", "fossils"}
+		for len(parents) > 0 || activeWorkers > 0 {
+
+			if len(parents) > 0 && activeWorkers < storage.numberOfThreads {
+				parent := parents[0]
+				parents = parents[1:]
+				activeWorkers++
+				go func(parent string) {
+					pathID, ok := storage.findPathID(parent)
+					if !ok {
+						return
+					}
+					entries, err := storage.listFiles(threadIndex, pathID, true, true)
+					if err != nil {
+						errorChannel <- err
+						return
+					}
+
+					LOG_DEBUG("GCD_STORAGE", "Listing %s; %d items returned", parent, len(entries))
+
 					files := []string {}
 					sizes := []int64 {}
-
-        for _, parent := range []string { "chunks", "fossils" } {
-            entries, err := storage.listFiles(storage.getPathID(parent), true)
-            if err != nil {
-                return nil, nil, err
-            }
-
 					for _, entry := range entries {
+						if entry.MimeType != GCDDirectoryMimeType {
 							name := entry.Name
-                if parent == "fossils" {
-                    name += ".fsl"
+							if strings.HasPrefix(parent, "fossils") {
+								name = parent + "/" + name + ".fsl"
+								name = name[len("fossils/"):]
+							} else {
+								name = parent + "/" + name
+								name = name[len("chunks/"):]
 							}
-                storage.savePathID(parent + "/" + entry.Name, entry.Id)
 							files = append(files, name)
 							sizes = append(sizes, entry.Size)
+						} else {
+							directoryChannel <- parent+"/"+entry.Name
+							storage.savePathID(parent+"/"+entry.Name, entry.Id)
 						}
 					}
-        return files, sizes, nil
+					lock.Lock()
+					allFiles = append(allFiles, files...)
+					allSizes = append(allSizes, sizes...)
+					lock.Unlock()
+					directoryChannel <- ""
+				} (parent)
+			}
+
+			if activeWorkers > 0 {
+				select {
+				case err := <- errorChannel:
+					return nil, nil, err
+				case directory := <- directoryChannel:
+					if directory == "" {
+						activeWorkers--
+					} else {
+						parents = append(parents, directory)
+					}
+				}
+			}
+		}
+
+		return allFiles, allSizes, nil
 	}
 
 }
@@ -374,18 +613,15 @@ func (storage *GCDStorage) ListFiles(threadIndex int, dir string) ([]string, []i
 // DeleteFile deletes the file or directory at 'filePath'.
 func (storage *GCDStorage) DeleteFile(threadIndex int, filePath string) (err error) {
 	filePath = storage.convertFilePath(filePath)
-    fileID, ok := storage.findPathID(filePath)
-    if !ok {
-        fileID, err = storage.getIDFromPath(filePath)
+	fileID, err := storage.getIDFromPath(threadIndex, filePath, false)
 	if err != nil {
 		LOG_TRACE("GCD_STORAGE", "Ignored file deletion error: %v", err)
 		return nil
 	}
-    }
 
 	for {
-        err = storage.service.Files.Delete(fileID).Fields("id").Do()
-        if retry, err := storage.shouldRetry(err); err == nil && !retry {
+		err = storage.service.Files.Delete(fileID).SupportsAllDrives(true).Fields("id").Do()
+		if retry, err := storage.shouldRetry(threadIndex, err); err == nil && !retry {
 			storage.deletePathID(filePath)
 			return nil
 		} else if retry {
@@ -406,21 +642,32 @@ func (storage *GCDStorage) MoveFile(threadIndex int, from string, to string) (er
 	from = storage.convertFilePath(from)
 	to = storage.convertFilePath(to)
 
-    fileID, ok := storage.findPathID(from)
-    if !ok {
-        return fmt.Errorf("Attempting to rename file %s with unknown id", to)
+	fileID, err := storage.getIDFromPath(threadIndex, from, false)
+	if err != nil {
+		return fmt.Errorf("Failed to retrieve the id of '%s': %v", from, err)
+	}
+	if fileID == "" {
+		return fmt.Errorf("The file '%s' to be moved does not exist", from)
 	}
 
-    fromParentID := storage.getPathID("chunks")
-    toParentID := storage.getPathID("fossils")
+	fromParent := path.Dir(from)
+	fromParentID, err := storage.getIDFromPath(threadIndex, fromParent, false)
+	if err != nil {
+		return fmt.Errorf("Failed to retrieve the id of the parent directory '%s': %v", fromParent, err)
+	}
+	if fromParentID == "" {
+		return fmt.Errorf("The parent directory '%s' does not exist", fromParent)
+	}
 
-    if strings.HasPrefix(from, "fossils") {
-        fromParentID, toParentID = toParentID, fromParentID
+	toParent := path.Dir(to)
+	toParentID, err := storage.getIDFromPath(threadIndex, toParent, true)
+	if err != nil {
+		return fmt.Errorf("Failed to retrieve the id of the parent directory '%s': %v", toParent, err)
 	}
 
 	for {
-        _, err = storage.service.Files.Update(fileID, nil).AddParents(toParentID).RemoveParents(fromParentID).Do()
-        if retry, err := storage.shouldRetry(err); err == nil && !retry {
+		_, err = storage.service.Files.Update(fileID, nil).SupportsAllDrives(true).AddParents(toParentID).RemoveParents(fromParentID).Do()
+		if retry, err := storage.shouldRetry(threadIndex, err); err == nil && !retry {
 			break
 		} else if retry {
 			continue
@@ -429,12 +676,10 @@ func (storage *GCDStorage) MoveFile(threadIndex int, from string, to string) (er
 		}
 	}
 
-    storage.savePathID(to, storage.getPathID(from))
-    storage.deletePathID(from)
 	return nil
 }
 
-// CreateDirectory creates a new directory.
+// createDirectory creates a new directory.
 func (storage *GCDStorage) CreateDirectory(threadIndex int, dir string) (err error) {
 
 	for len(dir) > 0 && dir[len(dir)-1] == '/' {
@@ -453,30 +698,42 @@ func (storage *GCDStorage) CreateDirectory(threadIndex int, dir string) (err err
 		return nil
 	}
 
-    parentID := storage.getPathID("")
-    name := dir
-
-    if strings.HasPrefix(dir, "snapshots/") {
-        parentID = storage.getPathID("snapshots")
-        name = dir[len("snapshots/"):]
+	parentDir := path.Dir(dir)
+	if parentDir == "." {
+		parentDir = ""
 	}
+	parentID := storage.getPathID(parentDir)
+	if parentID == "" {
+		return fmt.Errorf("Parent directory '%s' does not exist", parentDir)
+	}
+	name := path.Base(dir)
 
-    file := &drive.File {
+	var file *drive.File
+
+	for {
+		file = &drive.File{
 			Name:     name,
-        MimeType: "application/vnd.google-apps.folder",
+			MimeType: GCDDirectoryMimeType,
 			Parents:  []string{parentID},
 		}
 
-    for {
-        file, err = storage.service.Files.Create(file).Fields("id").Do()
-        if retry, err := storage.shouldRetry(err); err == nil && !retry {
+		file, err = storage.service.Files.Create(file).SupportsAllDrives(true).Fields("id").Do()
+		if retry, err := storage.shouldRetry(threadIndex, err); err == nil && !retry {
 			break
-        } else if retry {
+		} else {
+
+			// Check if the directory has already been created by other thread
+			if _, ok := storage.findPathID(dir); ok {
+				return nil
+			}
+
+			if retry {
 				continue
 			} else {
 				return err
 			}
 		}
+	}
 
 	storage.savePathID(dir, file.Id)
 	return nil
@@ -487,81 +744,64 @@ func (storage *GCDStorage) GetFileInfo(threadIndex int, filePath string) (exist
 	for len(filePath) > 0 && filePath[len(filePath)-1] == '/' {
 		filePath = filePath[:len(filePath)-1]
 	}
+	filePath = storage.convertFilePath(filePath)
 
-    // GetFileInfo is never called on a fossil
 	fileID, ok := storage.findPathID(filePath)
-    if !ok {
+	if ok {
+		// Only directories are saved in the case so this must be a directory
+		return true, true, 0, nil
+	}
+
 	dir := path.Dir(filePath)
 	if dir == "." {
 		dir = ""
 	}
-        dirID, err := storage.getIDFromPath(dir)
+	dirID, err := storage.getIDFromPath(threadIndex, dir, false)
 	if err != nil {
 		return false, false, 0, err
 	}
+	if dirID == "" {
+		return false, false, 0, nil
+	}
 
-        fileID, isDir, size, err = storage.listByName(dirID, path.Base(filePath))
-        if fileID != "" {
+	fileID, isDir, size, err = storage.listByName(threadIndex, dirID, path.Base(filePath))
+	if fileID != "" && isDir {
 		storage.savePathID(filePath, fileID)
 	}
 	return fileID != "", isDir, size, err
-    }
 
-    for {
-        file, err := storage.service.Files.Get(fileID).Fields("id, mimeType").Do()
-        if retry, err := storage.shouldRetry(err); err == nil && !retry {
-            return true, file.MimeType == "application/vnd.google-apps.folder", file.Size, nil
-        } else if retry {
-            continue
-        } else {
-            return false, false, 0, err
-        }
-    }
-}
-
-// FindChunk finds the chunk with the specified id.  If 'isFossil' is true, it will search for chunk files with
-// the suffix '.fsl'.
-func (storage *GCDStorage) FindChunk(threadIndex int, chunkID string, isFossil bool) (filePath string, exist bool, size int64, err error) {
-    parentID := ""
-    filePath = "chunks/" + chunkID
-    realPath := storage.convertFilePath(filePath)
-    if isFossil {
-        parentID = storage.getPathID("fossils")
-        filePath += ".fsl"
-    } else {
-        parentID = storage.getPathID("chunks")
-    }
-
-    fileID := ""
-    fileID, _, size, err = storage.listByName(parentID, chunkID)
-    if fileID != "" {
-        storage.savePathID(realPath, fileID)
-    }
-    return filePath, fileID != "", size, err
 }
 
 // DownloadFile reads the file at 'filePath' into the chunk.
 func (storage *GCDStorage) DownloadFile(threadIndex int, filePath string, chunk *Chunk) (err error) {
 	// We never download the fossil so there is no need to convert the path
-    fileID, ok := storage.findPathID(filePath)
-    if !ok {
-        fileID, err = storage.getIDFromPath(filePath)
+	fileID, err := storage.getIDFromPath(threadIndex, storage.convertFilePath(filePath), false)
 	if err != nil {
 		return err
 	}
-        storage.savePathID(filePath, fileID)
+	if fileID == "" {
+		return fmt.Errorf("%s does not exist", filePath)
 	}
 
 	var response *http.Response
 
 	for {
-        response, err = storage.service.Files.Get(fileID).Download()
-        if retry, err := storage.shouldRetry(err); err == nil && !retry {
+		// AcknowledgeAbuse(true) lets the download proceed even if GCD thinks that it contains malware.
+		// TODO: Should this prompt the user or log a warning?
+		req := storage.service.Files.Get(fileID).SupportsAllDrives(true)
+		if e, ok := err.(*googleapi.Error); ok {
+			if strings.Contains(err.Error(), "cannotDownloadAbusiveFile") || len(e.Errors) > 0 && e.Errors[0].Reason == "cannotDownloadAbusiveFile" {
+				LOG_WARN("GCD_STORAGE", "%s is marked as abusive, will download anyway.", filePath)
+				req = req.AcknowledgeAbuse(true)
+			}
+		}
+		response, err = req.Download()
+		if retry, retry_err := storage.shouldRetry(threadIndex, err); retry_err == nil && !retry {
 			break
 		} else if retry {
 			continue
 		} else {
-            return err
+			return retry_err
 		}
 	}
 
@@ -581,25 +821,21 @@ func (storage *GCDStorage) UploadFile(threadIndex int, filePath string, content
 		parent = ""
 	}
 
-    parentID, ok := storage.findPathID(parent)
-    if !ok {
-        parentID, err = storage.getIDFromPath(parent)
+	parentID, err := storage.getIDFromPath(threadIndex, parent, true)
 	if err != nil {
 		return err
 	}
-        storage.savePathID(parent, parentID)
-    }
 
 	file := &drive.File{
 		Name:     path.Base(filePath),
-        MimeType: "application/octet-stream",
+		MimeType: GCDFileMimeType,
 		Parents:  []string{parentID},
 	}
 
 	for {
 		reader := CreateRateLimitedReader(content, storage.UploadRateLimit/storage.numberOfThreads)
-        _, err = storage.service.Files.Create(file).Media(reader).Fields("id").Do()
-        if retry, err := storage.shouldRetry(err); err == nil && !retry {
+		_, err = storage.service.Files.Create(file).SupportsAllDrives(true).Media(reader).Fields("id").Do()
+		if retry, err := storage.shouldRetry(threadIndex, err); err == nil && !retry {
 			break
 		} else if retry {
 			continue
@@ -613,16 +849,16 @@ func (storage *GCDStorage) UploadFile(threadIndex int, filePath string, content
 
 // If a local snapshot cache is needed for the storage to avoid downloading/uploading chunks too often when
 // managing snapshots.
-func (storage *GCDStorage) IsCacheNeeded() (bool) { return true }
+func (storage *GCDStorage) IsCacheNeeded() bool { return true }
 
 // If the 'MoveFile' method is implemented.
-func (storage *GCDStorage) IsMoveFileImplemented() (bool) { return true }
+func (storage *GCDStorage) IsMoveFileImplemented() bool { return true }
 
 // If the storage can guarantee strong consistency.
-func (storage *GCDStorage) IsStrongConsistent() (bool) { return false }
+func (storage *GCDStorage) IsStrongConsistent() bool { return false }
 
 // If the storage supports fast listing of files names.
-func (storage *GCDStorage) IsFastListing() (bool) { return true }
+func (storage *GCDStorage) IsFastListing() bool { return true }
 
 // Enable the test mode.
 func (storage *GCDStorage) EnableTestMode() { storage.TestMode = true }

src/duplicacy_gcsstorage.go

@@ -5,33 +5,32 @@
 package duplicacy
 
 import (
-    "io"
-	"fmt"
-	"net"
-	"time"
-    "net/url"
-    "math/rand"
-    "io/ioutil"
 	"encoding/json"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"math/rand"
+	"net"
+	"net/url"
+	"time"
 
+	gcs "cloud.google.com/go/storage"
 	"golang.org/x/net/context"
 	"golang.org/x/oauth2"
 	"golang.org/x/oauth2/google"
-	gcs "cloud.google.com/go/storage"
+	"google.golang.org/api/googleapi"
 	"google.golang.org/api/iterator"
 	"google.golang.org/api/option"
-    "google.golang.org/api/googleapi"
 )
 
 type GCSStorage struct {
-    RateLimitedStorage
+	StorageBase
 
 	bucket     *gcs.BucketHandle
 	storageDir string
 
 	numberOfThreads int
 	TestMode        bool
-
 }
 
 type GCSConfig struct {
@@ -102,8 +101,9 @@ func CreateGCSStorage(tokenFile string, bucketName string, storageDir string, th
 		numberOfThreads: threads,
 	}
 
+	storage.DerivedStorage = storage
+	storage.SetDefaultNestingLevels([]int{0}, 0)
 	return storage, nil
-
 }
 
 func (storage *GCSStorage) shouldRetry(backoff *int, err error) (bool, error) {
@@ -149,7 +149,6 @@ func (storage *GCSStorage) shouldRetry(backoff *int, err error) (bool, error) {
 	return true, nil
 }
 
-
 // ListFiles return the list of files and subdirectories under 'dir' (non-recursively)
 func (storage *GCSStorage) ListFiles(threadIndex int, dir string) ([]string, []int64, error) {
 	for len(dir) > 0 && dir[len(dir)-1] == '/' {
@@ -240,19 +239,6 @@ func (storage *GCSStorage) GetFileInfo(threadIndex int, filePath string) (exist
 	return true, false, attributes.Size, nil
 }
 
-// FindChunk finds the chunk with the specified id.  If 'isFossil' is true, it will search for chunk files with
-// the suffix '.fsl'.
-func (storage *GCSStorage) FindChunk(threadIndex int, chunkID string, isFossil bool) (filePath string, exist bool, size int64, err error) {
-    filePath = "chunks/" + chunkID
-    if isFossil {
-        filePath += ".fsl"
-    }
-
-	exist, _, size, err = storage.GetFileInfo(threadIndex, filePath)
-
-	return filePath, exist, size, err
-}
-
 // DownloadFile reads the file at 'filePath' into the chunk.
 func (storage *GCSStorage) DownloadFile(threadIndex int, filePath string, chunk *Chunk) (err error) {
 	readCloser, err := storage.bucket.Object(storage.storageDir + filePath).NewReader(context.Background())
@@ -288,16 +274,16 @@ func (storage *GCSStorage) UploadFile(threadIndex int, filePath string, content
 
 // If a local snapshot cache is needed for the storage to avoid downloading/uploading chunks too often when
 // managing snapshots.
-func (storage *GCSStorage) IsCacheNeeded() (bool) { return true }
+func (storage *GCSStorage) IsCacheNeeded() bool { return true }
 
 // If the 'MoveFile' method is implemented.
-func (storage *GCSStorage) IsMoveFileImplemented() (bool) { return true }
+func (storage *GCSStorage) IsMoveFileImplemented() bool { return true }
 
 // If the storage can guarantee strong consistency.
-func (storage *GCSStorage) IsStrongConsistent() (bool) { return true }
+func (storage *GCSStorage) IsStrongConsistent() bool { return true }
 
 // If the storage supports fast listing of files names.
-func (storage *GCSStorage) IsFastListing() (bool) { return true }
+func (storage *GCSStorage) IsFastListing() bool { return true }
 
 // Enable the test mode.
 func (storage *GCSStorage) EnableTestMode() { storage.TestMode = true }

src/duplicacy_hubicclient.go

@@ -5,18 +5,18 @@
 package duplicacy
 
 import (
-    "fmt"
-    "net"
-    "time"
-    "sync"
 	"bytes"
-    "strings"
-    "io/ioutil"
 	"encoding/json"
+	"fmt"
 	"io"
+	"io/ioutil"
+	"math/rand"
+	"net"
 	"net/http"
 	net_url "net/url"
-    "math/rand"
+	"strings"
+	"sync"
+	"time"
 
 	"golang.org/x/oauth2"
 )
@@ -72,7 +72,7 @@ func NewHubicClient(tokenFile string) (*HubicClient, error) {
 					KeepAlive: 30 * time.Second,
 				}).Dial,
 				TLSHandshakeTimeout:   60 * time.Second,
-                ResponseHeaderTimeout: 30 * time.Second,
+				ResponseHeaderTimeout: 300 * time.Second,
 				ExpectContinueTimeout: 10 * time.Second,
 			},
 		},
@@ -82,7 +82,7 @@ func NewHubicClient(tokenFile string) (*HubicClient, error) {
 		CredentialLock: &sync.Mutex{},
 	}
 
-    err = client.RefreshToken()
+	err = client.RefreshToken(false)
 	if err != nil {
 		return nil, err
 	}
@@ -100,7 +100,7 @@ func (client *HubicClient) call(url string, method string, input interface{}, ex
 	var response *http.Response
 
 	backoff := 1
-    for i := 0; i < 8; i++ {
+	for i := 0; i < 11; i++ {
 
 		LOG_DEBUG("HUBIC_CALL", "%s %s", method, url)
 
@@ -151,6 +151,13 @@ func (client *HubicClient) call(url string, method string, input interface{}, ex
 
 		response, err = client.HTTPClient.Do(request)
 		if err != nil {
+			if url != HubicCredentialURL {
+				retryAfter := time.Duration((0.5 + rand.Float32()) * 1000.0 * float32(backoff))
+				LOG_INFO("HUBIC_CALL", "%s %s returned an error: %v; retry after %d milliseconds", method, url, err, retryAfter)
+				time.Sleep(retryAfter * time.Millisecond)
+				backoff *= 2
+				continue
+			}
 			return nil, 0, "", err
 		}
 
@@ -179,7 +186,7 @@ func (client *HubicClient) call(url string, method string, input interface{}, ex
 				return nil, 0, "", HubicError{Status: response.StatusCode, Message: "Authorization error when retrieving credentials"}
 			}
 
-            err = client.RefreshToken()
+			err = client.RefreshToken(true)
 			if err != nil {
 				return nil, 0, "", err
 			}
@@ -190,7 +197,13 @@ func (client *HubicClient) call(url string, method string, input interface{}, ex
 			}
 			continue
 		} else if response.StatusCode >= 500 && response.StatusCode < 600 {
-            retryAfter := time.Duration(rand.Float32() * 1000.0 * float32(backoff))
+			retryAfter := time.Duration((0.5 + rand.Float32()) * 1000.0 * float32(backoff))
+			LOG_INFO("HUBIC_RETRY", "Response status: %d; retry after %d milliseconds", response.StatusCode, retryAfter)
+			time.Sleep(retryAfter * time.Millisecond)
+			backoff *= 2
+			continue
+		} else if response.StatusCode == 408 {
+			retryAfter := time.Duration((0.5 + rand.Float32()) * 1000.0 * float32(backoff))
 			LOG_INFO("HUBIC_RETRY", "Response status: %d; retry after %d milliseconds", response.StatusCode, retryAfter)
 			time.Sleep(retryAfter * time.Millisecond)
 			backoff *= 2
@@ -203,11 +216,11 @@ func (client *HubicClient) call(url string, method string, input interface{}, ex
 	return nil, 0, "", fmt.Errorf("Maximum number of retries reached")
 }
 
-func (client *HubicClient) RefreshToken() (err error) {
+func (client *HubicClient) RefreshToken(force bool) (err error) {
 	client.TokenLock.Lock()
 	defer client.TokenLock.Unlock()
 
-    if client.Token.Valid() {
+	if !force && client.Token.Valid() {
 		return nil
 	}
 
@@ -436,7 +449,7 @@ func (client *HubicClient) MoveFile(from string, to string) error {
 	return client.DeleteFile(from)
 }
 
-func (client *HubicClient) CreateDirectory(path string) (error) {
+func (client *HubicClient) CreateDirectory(path string) error {
 
 	for len(path) > 0 && path[len(path)-1] == '/' {
 		path = path[:len(path)-1]

src/duplicacy_hubicclient_test.go

@@ -1,149 +0,0 @@
-// Copyright (c) Acrosync LLC. All rights reserved.
-// Free for personal use and commercial trial
-// Commercial use requires per-user licenses available from https://duplicacy.com
-
-package duplicacy
-
-import (
-    "io"
-    "fmt"
-    "testing"
-    "crypto/sha256"
-    "encoding/hex"
-
-    crypto_rand "crypto/rand"
-    "math/rand"
-)
-
-func TestHubicClient(t *testing.T) {
-
-    hubicClient, err := NewHubicClient("hubic-token.json")
-    if err != nil {
-        t.Errorf("Failed to create the Hubic client: %v", err)
-        return
-    }
-
-    hubicClient.TestMode = true
-
-    existingFiles, err := hubicClient.ListEntries("")
-    for _, file := range existingFiles {
-        fmt.Printf("name: %s, isDir: %t\n", file.Name, file.Type == "application/directory")
-    }
-
-    testExists, _, _, err := hubicClient.GetFileInfo("test")
-    if err != nil {
-        t.Errorf("Failed to list the test directory: %v", err)
-        return
-    }
-    if !testExists {
-        err = hubicClient.CreateDirectory("test")
-        if err != nil {
-            t.Errorf("Failed to create the test directory: %v", err)
-            return
-        }
-    }
-
-    test1Exists, _, _, err := hubicClient.GetFileInfo("test/test1")
-    if err != nil {
-        t.Errorf("Failed to list the test1 directory: %v", err)
-        return
-    }
-    if !test1Exists {
-        err = hubicClient.CreateDirectory("test/test1")
-        if err != nil {
-            t.Errorf("Failed to create the test1 directory: %v", err)
-            return
-        }
-    }
-
-    test2Exists, _, _, err := hubicClient.GetFileInfo("test/test2")
-    if err != nil {
-        t.Errorf("Failed to list the test2 directory: %v", err)
-        return
-    }
-    if !test2Exists {
-        err = hubicClient.CreateDirectory("test/test2")
-        if err != nil {
-            t.Errorf("Failed to create the test2 directory: %v", err)
-            return
-        }
-    }
-
-    numberOfFiles := 20
-    maxFileSize := 64 * 1024
-
-    for i := 0; i < numberOfFiles; i++ {
-        content := make([]byte, rand.Int() % maxFileSize + 1)
-        _, err = crypto_rand.Read(content)
-        if err != nil {
-            t.Errorf("Error generating random content: %v", err)
-            return
-        }
-
-        hasher := sha256.New()
-        hasher.Write(content)
-        filename := hex.EncodeToString(hasher.Sum(nil))
-
-        fmt.Printf("file: %s\n", filename)
-
-        err = hubicClient.UploadFile("test/test1/" + filename, content, 100)
-        if err != nil {
-            /*if e, ok := err.(ACDError); !ok || e.Status != 409 */ {
-                t.Errorf("Failed to upload the file %s: %v", filename, err)
-                return
-            }
-        }
-    }
-
-    entries, err := hubicClient.ListEntries("test/test1")
-    if err != nil {
-        t.Errorf("Error list randomly generated files: %v", err)
-        return
-    }
-
-    for _, entry := range entries {
-
-        exists, isDir, size, err := hubicClient.GetFileInfo("test/test1/" + entry.Name)
-        fmt.Printf("%s exists: %t, isDir: %t, size: %d, err: %v\n", "test/test1/" + entry.Name, exists, isDir, size, err)
-
-        err = hubicClient.MoveFile("test/test1/" + entry.Name, "test/test2/" + entry.Name)
-        if err != nil {
-            t.Errorf("Failed to move %s: %v", entry.Name, err)
-            return
-        }
-    }
-
-    entries, err = hubicClient.ListEntries("test/test2")
-    if err != nil {
-        t.Errorf("Error list randomly generated files: %v", err)
-        return
-    }
-
-    for _, entry := range entries {
-        readCloser, _, err := hubicClient.DownloadFile("test/test2/" + entry.Name)
-        if err != nil {
-            t.Errorf("Error downloading file %s: %v", entry.Name, err)
-            return
-        }
-
-        hasher := sha256.New()
-        io.Copy(hasher, readCloser)
-        hash := hex.EncodeToString(hasher.Sum(nil))
-
-        if hash != entry.Name {
-            t.Errorf("File %s, hash %s", entry.Name, hash)
-        }
-
-        readCloser.Close()
-    }
-
-    for _, entry := range entries {
-
-        err = hubicClient.DeleteFile("test/test2/" + entry.Name)
-        if err != nil {
-            t.Errorf("Failed to delete the file %s: %v", entry.Name, err)
-            return
-        }
-    }
-
-}

src/duplicacy_hubicstorage.go

@@ -10,7 +10,7 @@ import (
 )
 
 type HubicStorage struct {
-    RateLimitedStorage
+	StorageBase
 
 	client          *HubicClient
 	storageDir      string
@@ -64,8 +64,9 @@ func CreateHubicStorage(tokenFile string, storagePath string, threads int) (stor
 		}
 	}
 
+	storage.DerivedStorage = storage
+	storage.SetDefaultNestingLevels([]int{0}, 0)
 	return storage, nil
-
 }
 
 // ListFiles return the list of files and subdirectories under 'dir' (non-recursively)
@@ -105,18 +106,20 @@ func (storage *HubicStorage) ListFiles(threadIndex int, dir string) ([]string, [
 	} else {
 		files := []string{}
 		sizes := []int64{}
-        entries, err := storage.client.ListEntries(storage.storageDir + "/chunks")
+		entries, err := storage.client.ListEntries(storage.storageDir + "/" + dir)
 		if err != nil {
 			return nil, nil, err
 		}
 
 		for _, entry := range entries {
 			if entry.Type == "application/directory" {
-                continue
-            }
+				files = append(files, entry.Name+"/")
+				sizes = append(sizes, 0)
+			} else {
 				files = append(files, entry.Name)
 				sizes = append(sizes, entry.Size)
 			}
+		}
 		return files, sizes, nil
 	}
 
@@ -158,18 +161,6 @@ func (storage *HubicStorage) GetFileInfo(threadIndex int, filePath string) (exis
 	return storage.client.GetFileInfo(storage.storageDir + "/" + filePath)
 }
 
-// FindChunk finds the chunk with the specified id.  If 'isFossil' is true, it will search for chunk files with
-// the suffix '.fsl'.
-func (storage *HubicStorage) FindChunk(threadIndex int, chunkID string, isFossil bool) (filePath string, exist bool, size int64, err error) {
-    filePath = "chunks/" + chunkID
-    if isFossil {
-        filePath += ".fsl"
-    }
-
-    exist, _, size, err = storage.client.GetFileInfo(storage.storageDir + "/" + filePath)
-    return filePath, exist, size, err
-}
-
 // DownloadFile reads the file at 'filePath' into the chunk.
 func (storage *HubicStorage) DownloadFile(threadIndex int, filePath string, chunk *Chunk) (err error) {
 	readCloser, _, err := storage.client.DownloadFile(storage.storageDir + "/" + filePath)
@@ -190,16 +181,16 @@ func (storage *HubicStorage) UploadFile(threadIndex int, filePath string, conten
 
 // If a local snapshot cache is needed for the storage to avoid downloading/uploading chunks too often when
 // managing snapshots.
-func (storage *HubicStorage) IsCacheNeeded() (bool) { return true }
+func (storage *HubicStorage) IsCacheNeeded() bool { return true }
 
 // If the 'MoveFile' method is implemented.
-func (storage *HubicStorage) IsMoveFileImplemented() (bool) { return true }
+func (storage *HubicStorage) IsMoveFileImplemented() bool { return true }
 
 // If the storage can guarantee strong consistency.
-func (storage *HubicStorage) IsStrongConsistent() (bool) { return false }
+func (storage *HubicStorage) IsStrongConsistent() bool { return false }
 
 // If the storage supports fast listing of files names.
-func (storage *HubicStorage) IsFastListing() (bool) { return true }
+func (storage *HubicStorage) IsFastListing() bool { return true }
 
 // Enable the test mode.
 func (storage *HubicStorage) EnableTestMode() {

src/duplicacy_keyring_windows.go

@@ -5,10 +5,10 @@
 package duplicacy
 
 import (
+	"encoding/json"
+	"io/ioutil"
 	"syscall"
 	"unsafe"
-    "io/ioutil"
-    "encoding/json"
 )
 
 var keyringFile string
@@ -136,6 +136,16 @@ func keyringSet(key string, value string) bool {
 	if value == "" {
 		keyring[key] = nil
 	} else {
+
+		// Check if the value to be set is the same as the existing one
+		existingEncryptedValue := keyring[key]
+		if len(existingEncryptedValue) > 0 {
+			existingValue, err := keyringDecrypt(existingEncryptedValue)
+			if err == nil && string(existingValue) == value {
+				return true
+			}
+		}
+
 		encryptedValue, err := keyringEncrypt([]byte(value))
 		if err != nil {
 			LOG_DEBUG("KEYRING_ENCRYPT", "Failed to encrypt the value: %v", err)

src/duplicacy_log.go

@@ -5,12 +5,14 @@
 package duplicacy
 
 import (
-    "os"
 	"fmt"
-    "time"
+	"os"
+	"log"
+	"runtime/debug"
 	"sync"
 	"testing"
-    "runtime/debug"
+	"time"
+	"regexp"
 )
 
 const (
@@ -23,6 +25,7 @@ const (
 	ASSERT = 4
 )
 
+var LogFunction func(level int, logID string, message string)
 
 var printLogHeader = false
 
@@ -42,6 +45,13 @@ func setTestingT(t *testing.T) {
 	testingT = t
 }
 
+// Contains the ids of logs that won't be displayed
+var suppressedLogs map[string]bool = map[string]bool{}
+
+func SuppressLog(id string) {
+	suppressedLogs[id] = true
+}
+
 func getLevelName(level int) string {
 	switch level {
 	case DEBUG:
@@ -97,6 +107,15 @@ func LOG_ERROR(logID string, format string, v ...interface{}) {
 	logf(ERROR, logID, format, v...)
 }
 
+func LOG_WERROR(isWarning bool, logID string, format string, v ...interface{}) {
+	if isWarning {
+		logf(WARN, logID, format, v...)
+	} else {
+		logf(ERROR, logID, format, v...)
+	}
+}
+
+
 func LOG_FATAL(logID string, format string, v ...interface{}) {
 	logf(FATAL, logID, format, v...)
 }
@@ -117,13 +136,18 @@ func logf(level int, logID string, format string, v ...interface{}) {
 
 	message := fmt.Sprintf(format, v...)
 
+	if LogFunction != nil {
+		LogFunction(level, logID, message)
+		return
+	}
+
 	now := time.Now()
 
 	// Uncomment this line to enable unbufferred logging for tests
 	// fmt.Printf("%s %s %s %s\n", now.Format("2006-01-02 15:04:05.000"), getLevelName(level), logID, message)
 
 	if testingT != nil {
-        if level < WARN {
+		if level <= WARN {
 			if level >= loggingLevel {
 				testingT.Logf("%s %s %s %s\n",
 					now.Format("2006-01-02 15:04:05.000"), getLevelName(level), logID, message)
@@ -137,6 +161,12 @@ func logf(level int, logID string, format string, v ...interface{}) {
 		defer logMutex.Unlock()
 
 		if level >= loggingLevel {
+			if level <= ERROR && len(suppressedLogs) > 0 {
+				if _, found := suppressedLogs[logID]; found {
+					return
+				}
+			}
+
 			if printLogHeader {
 				fmt.Printf("%s %s %s %s\n",
 					now.Format("2006-01-02 15:04:05.000"), getLevelName(level), logID, message)
@@ -155,6 +185,32 @@ func logf(level int, logID string, format string, v ...interface{}) {
 	}
 }
 
+// Set up logging for libraries that Duplicacy depends on.  They can call 'log.Printf("[ID] message")'
+// to produce logs in Duplicacy's format
+type Logger struct {
+	formatRegex *regexp.Regexp
+}
+
+func (logger *Logger) Write(line []byte) (n int, err error) {
+	n = len(line)
+	for len(line) > 0 && line[len(line) - 1] == '\n' {
+		line = line[:len(line) - 1]
+	}
+	matched := logger.formatRegex.FindStringSubmatch(string(line))
+	if matched != nil {
+		LOG_INFO(matched[1], "%s", matched[2])
+	} else {
+		LOG_INFO("LOG_DEFAULT", "%s", line)
+	}
+
+    return
+}
+
+func init() {
+	log.SetFlags(0)
+	log.SetOutput(&Logger{ formatRegex: regexp.MustCompile(`^\[(.+)\]\s*(.+)`) })
+}
+
 const (
 	duplicacyExitCode = 100
 	otherExitCode     = 101

src/duplicacy_oneclient.go

@@ -5,16 +5,19 @@
 package duplicacy
 
 import (
-    "fmt"
-    "time"
-    "sync"
+	"context"
 	"bytes"
-    "strings"
-    "io/ioutil"
 	"encoding/json"
+	"fmt"
 	"io"
-    "net/http"
+	"io/ioutil"
 	"math/rand"
+	"net/http"
+	"strings"
+	"strconv"
+	"sync"
+	"time"
+	"path/filepath"
 
 	"golang.org/x/oauth2"
 )
@@ -32,21 +35,23 @@ type OneDriveErrorResponse struct {
 	Error OneDriveError `json:"error"`
 }
 
-var OneDriveRefreshTokenURL = "https://duplicacy.com/one_refresh"
-var OneDriveAPIURL = "https://api.onedrive.com/v1.0"
-
 type OneDriveClient struct {
 	HTTPClient *http.Client
 
 	TokenFile string
 	Token     *oauth2.Token
+	OAConfig  *oauth2.Config
 	TokenLock *sync.Mutex
 
 	IsConnected bool
 	TestMode    bool
+
+	IsBusiness bool
+	RefreshTokenURL string
+	APIURL string
 }
 
-func NewOneDriveClient(tokenFile string) (*OneDriveClient, error) {
+func NewOneDriveClient(tokenFile string, isBusiness bool, client_id string, client_secret string, drive_id string) (*OneDriveClient, error) {
 
 	description, err := ioutil.ReadFile(tokenFile)
 	if err != nil {
@@ -62,9 +67,38 @@ func NewOneDriveClient(tokenFile string) (*OneDriveClient, error) {
 		HTTPClient: http.DefaultClient,
 		TokenFile:  tokenFile,
 		Token:      token,
+		OAConfig:	nil,
 		TokenLock:  &sync.Mutex{},
+		IsBusiness: isBusiness,
 	}
 
+	if (client_id != "") {
+	    oneOauthConfig := oauth2.Config{
+	        ClientID: 		client_id,
+	        ClientSecret: 	client_secret,
+	        Scopes:       	[]string{"Files.ReadWrite", "offline_access"},
+	        Endpoint: oauth2.Endpoint{
+	            AuthURL:  "https://login.microsoftonline.com/common/oauth2/v2.0/authorize",
+	            TokenURL: "https://login.microsoftonline.com/common/oauth2/v2.0/token",
+	        },
+	    }
+
+		client.OAConfig = &oneOauthConfig
+	}
+
+	if isBusiness {
+		client.RefreshTokenURL = "https://duplicacy.com/odb_refresh"
+		client.APIURL = "https://graph.microsoft.com/v1.0/me/drive"
+		if drive_id != "" {
+			client.APIURL = "https://graph.microsoft.com/v1.0/drives/"+drive_id
+		}
+	} else {
+		client.RefreshTokenURL = "https://duplicacy.com/one_refresh"
+		client.APIURL = "https://api.onedrive.com/v1.0/drive"
+	}
+
+	client.RefreshToken(false)
+
 	return client, nil
 }
 
@@ -73,7 +107,7 @@ func (client *OneDriveClient) call(url string, method string, input interface{},
 	var response *http.Response
 
 	backoff := 1
-    for i := 0; i < 8; i++ {
+	for i := 0; i < 12; i++ {
 
 		LOG_DEBUG("ONEDRIVE_CALL", "%s %s", method, url)
 
@@ -89,7 +123,7 @@ func (client *OneDriveClient) call(url string, method string, input interface{},
 		case []byte:
 			inputReader = bytes.NewReader(input.([]byte))
 		case int:
-            inputReader = bytes.NewReader([]byte(""))
+			inputReader = nil
 		case *bytes.Buffer:
 			inputReader = bytes.NewReader(input.(*bytes.Buffer).Bytes())
 		case *RateLimitedReader:
@@ -104,9 +138,10 @@ func (client *OneDriveClient) call(url string, method string, input interface{},
 
 		if reader, ok := inputReader.(*RateLimitedReader); ok {
 			request.ContentLength = reader.Length()
+			request.Header.Set("Content-Range", fmt.Sprintf("bytes 0-%d/%d", reader.Length() - 1, reader.Length()))
 		}
 
-        if url != OneDriveRefreshTokenURL {
+		if url != client.RefreshTokenURL {
 			client.TokenLock.Lock()
 			request.Header.Set("Authorization", "Bearer "+client.Token.AccessToken)
 			client.TokenLock.Unlock()
@@ -115,6 +150,8 @@ func (client *OneDriveClient) call(url string, method string, input interface{},
 			request.Header.Set("Content-Type", contentType)
 		}
 
+		request.Header.Set("User-Agent", "ISV|Acrosync|Duplicacy/2.0")
+
 		response, err = client.HTTPClient.Do(request)
 		if err != nil {
 			if client.IsConnected {
@@ -131,6 +168,9 @@ func (client *OneDriveClient) call(url string, method string, input interface{},
 					time.Sleep(retryAfter * time.Millisecond)
 				}
 				backoff *= 2
+				if backoff > 256 {
+					backoff = 256
+				}
 				continue
 			}
 			return nil, 0, err
@@ -150,24 +190,36 @@ func (client *OneDriveClient) call(url string, method string, input interface{},
 
 		if response.StatusCode == 401 {
 
-            if url == OneDriveRefreshTokenURL {
+			if url == client.RefreshTokenURL {
 				return nil, 0, OneDriveError{Status: response.StatusCode, Message: "Authorization error when refreshing token"}
 			}
 
-            err = client.RefreshToken()
+			err = client.RefreshToken(true)
 			if err != nil {
 				return nil, 0, err
 			}
 			continue
+		} else if response.StatusCode == 409 {
+			return nil, 0, OneDriveError{Status: response.StatusCode, Message: "Conflict"}
 		} else if response.StatusCode > 401 && response.StatusCode != 404 {
-            retryAfter := time.Duration(rand.Float32() * 1000.0 * float32(backoff))
-            LOG_INFO("ONEDRIVE_RETRY", "Response code: %d; retry after %d milliseconds", response.StatusCode, retryAfter)
-            time.Sleep(retryAfter * time.Millisecond)
+			delay := int((rand.Float32() * 0.5 + 0.5) * 1000.0 * float32(backoff))
+			if backoffList, found := response.Header["Retry-After"]; found && len(backoffList) > 0 {
+				retryAfter, _ := strconv.Atoi(backoffList[0])
+				if retryAfter * 1000 > delay {
+					delay = retryAfter * 1000
+				}
+			}
+
+			LOG_INFO("ONEDRIVE_RETRY", "Response code: %d; retry after %d milliseconds", response.StatusCode, delay)
+			time.Sleep(time.Duration(delay) * time.Millisecond)
 			backoff *= 2
+			if backoff > 256 {
+				backoff = 256
+			}
 			continue
 		} else {
 			if err := json.NewDecoder(response.Body).Decode(errorResponse); err != nil {
-                return nil, 0, OneDriveError { Status: response.StatusCode, Message: fmt.Sprintf("Unexpected response"), }
+				return nil, 0, OneDriveError{Status: response.StatusCode, Message: fmt.Sprintf("Unexpected response")}
 			}
 
 			errorResponse.Error.Status = response.StatusCode
@@ -178,15 +230,16 @@ func (client *OneDriveClient) call(url string, method string, input interface{},
 	return nil, 0, fmt.Errorf("Maximum number of retries reached")
 }
 
-func (client *OneDriveClient) RefreshToken() (err error) {
+func (client *OneDriveClient) RefreshToken(force bool) (err error) {
 	client.TokenLock.Lock()
 	defer client.TokenLock.Unlock()
 
-    if client.Token.Valid() {
+	if !force && client.Token.Valid() {
 		return nil
 	}
 
-    readCloser, _, err := client.call(OneDriveRefreshTokenURL, "POST", client.Token, "")
+	if (client.OAConfig == nil) {
+		readCloser, _, err := client.call(client.RefreshTokenURL, "POST", client.Token, "")
 		if err != nil {
 			return fmt.Errorf("failed to refresh the access token: %v", err)
 		}
@@ -196,6 +249,15 @@ func (client *OneDriveClient) RefreshToken() (err error) {
 		if err = json.NewDecoder(readCloser).Decode(client.Token); err != nil {
 			return err
 		}
+	} else {
+		ctx := context.Background()
+		tokenSource := client.OAConfig.TokenSource(ctx, client.Token)
+	    token, err := tokenSource.Token()
+	    if err != nil {
+	        return fmt.Errorf("failed to refresh the access token: %v", err)
+	    }
+	    client.Token = token
+	}
 
 	description, err := json.Marshal(client.Token)
 	if err != nil {
@@ -226,9 +288,9 @@ func (client *OneDriveClient) ListEntries(path string) ([]OneDriveEntry, error)
 
 	entries := []OneDriveEntry{}
 
-    url := OneDriveAPIURL + "/drive/root:/" + path + ":/children"
+	url := client.APIURL + "/root:/" + path + ":/children"
 	if path == "" {
-        url = OneDriveAPIURL + "/drive/root/children"
+		url = client.APIURL + "/root/children"
 	}
 	if client.TestMode {
 		url += "?top=8"
@@ -264,7 +326,8 @@ func (client *OneDriveClient) ListEntries(path string) ([]OneDriveEntry, error)
 
 func (client *OneDriveClient) GetFileInfo(path string) (string, bool, int64, error) {
 
-    url := OneDriveAPIURL + "/drive/root:/" + path
+	url := client.APIURL + "/root:/" + path
+	if path == "" { url = client.APIURL + "/root" }
 	url += "?select=id,name,size,folder"
 
 	readCloser, _, err := client.call(url, "GET", 0, "")
@@ -289,17 +352,19 @@ func (client *OneDriveClient) GetFileInfo(path string) (string, bool, int64, err
 
 func (client *OneDriveClient) DownloadFile(path string) (io.ReadCloser, int64, error) {
 
-    url := OneDriveAPIURL + "/drive/items/root:/" + path + ":/content"
+	url := client.APIURL + "/items/root:/" + path + ":/content"
 
 	return client.call(url, "GET", 0, "")
 }
 
 func (client *OneDriveClient) UploadFile(path string, content []byte, rateLimit int) (err error) {
 
-    url := OneDriveAPIURL + "/drive/root:/" + path + ":/content"
+	// Upload file using the simple method; this is only possible for OneDrive Personal or if the file
+	// is smaller than 4MB for OneDrive Business
+	if !client.IsBusiness || (client.TestMode && rand.Int() % 2 == 0) {
+		url := client.APIURL + "/root:/" + path + ":/content"
 
 		readCloser, _, err := client.call(url, "PUT", CreateRateLimitedReader(content, rateLimit), "application/octet-stream")
-
 		if err != nil {
 			return err
 		}
@@ -308,9 +373,74 @@ func (client *OneDriveClient) UploadFile(path string, content []byte, rateLimit
 		return nil
 	}
 
+	// For large files, create an upload session first
+	uploadURL, err := client.CreateUploadSession(path)
+	if err != nil {
+		return err
+	}
+
+	return client.UploadFileSession(uploadURL, content, rateLimit)
+}
+
+func (client *OneDriveClient) CreateUploadSession(path string) (uploadURL string, err error) {
+
+	type CreateUploadSessionItem struct {
+		ConflictBehavior string `json:"@microsoft.graph.conflictBehavior"`
+		Name string `json:"name"`
+	}
+
+	input := map[string]interface{} {
+		"item": CreateUploadSessionItem {
+			ConflictBehavior: "replace",
+			Name: filepath.Base(path),
+		},
+	}
+
+	readCloser, _, err := client.call(client.APIURL + "/root:/" + path + ":/createUploadSession", "POST", input, "application/json")
+	if err != nil {
+		return "", err
+	}
+
+	type CreateUploadSessionOutput struct {
+		UploadURL string `json:"uploadUrl"`
+	}
+
+	output := &CreateUploadSessionOutput{}
+
+	if err = json.NewDecoder(readCloser).Decode(&output); err != nil {
+		return "", err
+	}
+
+	readCloser.Close()
+	return output.UploadURL, nil
+}
+
+func (client *OneDriveClient) UploadFileSession(uploadURL string, content []byte, rateLimit int) (err error) {
+
+	readCloser, _, err := client.call(uploadURL, "PUT", CreateRateLimitedReader(content, rateLimit), "")
+	if err != nil {
+		return err
+	}
+	type UploadFileSessionOutput struct {
+		Size int `json:"size"`
+	}
+	output := &UploadFileSessionOutput{}
+
+	if err = json.NewDecoder(readCloser).Decode(&output); err != nil {
+		return fmt.Errorf("Failed to complete the file upload session: %v", err)
+	}
+
+	if output.Size != len(content) {
+		return fmt.Errorf("Uploaded %d bytes out of %d bytes", output.Size, len(content))
+	}
+
+	readCloser.Close()
+	return nil
+}
+
 func (client *OneDriveClient) DeleteFile(path string) error {
 
-    url := OneDriveAPIURL + "/drive/root:/" + path
+	url := client.APIURL + "/root:/" + path
 
 	readCloser, _, err := client.call(url, "DELETE", 0, "")
 	if err != nil {
@@ -323,16 +453,30 @@ func (client *OneDriveClient) DeleteFile(path string) error {
 
 func (client *OneDriveClient) MoveFile(path string, parent string) error {
 
-    url := OneDriveAPIURL + "/drive/root:/" + path
+	url := client.APIURL + "/root:/" + path
 
 	parentReference := make(map[string]string)
-    parentReference["path"] = "/drive/root:/" + parent
+	parentReference["path"] = "/root:/" + parent
 
 	parameters := make(map[string]interface{})
 	parameters["parentReference"] = parentReference
 
 	readCloser, _, err := client.call(url, "PATCH", parameters, "application/json")
 	if err != nil {
+		if e, ok := err.(OneDriveError); ok && e.Status == 400 {
+			// The destination directory doesn't exist; trying to create it...
+			dir := filepath.Dir(parent)
+			if dir == "." {
+				dir = ""
+			}
+			client.CreateDirectory(dir, filepath.Base(parent))
+			readCloser, _, err = client.call(url, "PATCH", parameters, "application/json")
+			if err != nil {
+				return nil
+			}
+
+		}
+
 		return err
 	}
 
@@ -340,26 +484,31 @@ func (client *OneDriveClient) MoveFile(path string, parent string) error {
 	return nil
 }
 
-func (client *OneDriveClient) CreateDirectory(path string, name string) (error) {
+func (client *OneDriveClient) CreateDirectory(path string, name string) error {
 
-    url := OneDriveAPIURL + "/root/children"
+	url := client.APIURL + "/root/children"
 
 	if path != "" {
 
-        parentID, isDir, _, err := client.GetFileInfo(path)
+		pathID, isDir, _, err := client.GetFileInfo(path)
 		if err != nil {
 			return err
 		}
 
-        if parentID == "" {
-            return fmt.Errorf("The path '%s' does not exist", path)
+		if pathID == "" {
+			dir := filepath.Dir(path)
+			if dir != "." {
+				// The parent directory doesn't exist; trying to create it...
+				client.CreateDirectory(dir, filepath.Base(path))
+				isDir = true
+			}
 		}
 
 		if !isDir {
 			return fmt.Errorf("The path '%s' is not a directory", path)
 		}
 
-        url = OneDriveAPIURL + "/drive/items/" + parentID + "/children"
+		url = client.APIURL + "/root:/" + path + ":/children"
 	}
 
 	parameters := make(map[string]interface{})
@@ -368,6 +517,11 @@ func (client *OneDriveClient) CreateDirectory(path string, name string) (error)
 
 	readCloser, _, err := client.call(url, "POST", parameters, "application/json")
 	if err != nil {
+		if e, ok := err.(OneDriveError); ok && e.Status == 409 {
+			// This error usually means the directory already exists
+			LOG_TRACE("ONEDRIVE_MKDIR", "The directory '%s/%s' already exists", path, name)
+			return nil
+		}
 		return err
 	}
 

src/duplicacy_oneclient_test.go

@@ -1,146 +0,0 @@
-// Copyright (c) Acrosync LLC. All rights reserved.
-// Free for personal use and commercial trial
-// Commercial use requires per-user licenses available from https://duplicacy.com
-
-package duplicacy
-
-import (
-    "io"
-    "fmt"
-    "testing"
-    "crypto/sha256"
-    "encoding/hex"
-
-    crypto_rand "crypto/rand"
-    "math/rand"
-)
-
-func TestOneDriveClient(t *testing.T) {
-
-    oneDriveClient, err := NewOneDriveClient("one-token.json")
-    if err != nil {
-        t.Errorf("Failed to create the OneDrive client: %v", err)
-        return
-    }
-
-    oneDriveClient.TestMode = true
-
-    existingFiles, err := oneDriveClient.ListEntries("")
-    for _, file := range existingFiles {
-        fmt.Printf("name: %s, isDir: %t\n", file.Name, len(file.Folder) != 0)
-    }
-
-
-    testID, _, _, err := oneDriveClient.GetFileInfo("test")
-    if err != nil {
-        t.Errorf("Failed to list the test directory: %v", err)
-        return
-    }
-    if testID == "" {
-        err = oneDriveClient.CreateDirectory("", "test")
-        if err != nil {
-            t.Errorf("Failed to create the test directory: %v", err)
-            return
-        }
-    }
-
-    test1ID, _, _, err := oneDriveClient.GetFileInfo("test/test1")
-    if err != nil {
-        t.Errorf("Failed to list the test1 directory: %v", err)
-        return
-    }
-    if test1ID == "" {
-        err = oneDriveClient.CreateDirectory("test", "test1")
-        if err != nil {
-            t.Errorf("Failed to create the test1 directory: %v", err)
-            return
-        }
-    }
-
-    test2ID, _, _, err := oneDriveClient.GetFileInfo("test/test2")
-    if err != nil {
-        t.Errorf("Failed to list the test2 directory: %v", err)
-        return
-    }
-    if test2ID == "" {
-        err = oneDriveClient.CreateDirectory("test", "test2")
-        if err != nil {
-            t.Errorf("Failed to create the test2 directory: %v", err)
-            return
-        }
-    }
-
-    numberOfFiles := 20
-    maxFileSize := 64 * 1024
-
-    for i := 0; i < numberOfFiles; i++ {
-        content := make([]byte, rand.Int() % maxFileSize + 1)
-        _, err = crypto_rand.Read(content)
-        if err != nil {
-            t.Errorf("Error generating random content: %v", err)
-            return
-        }
-
-        hasher := sha256.New()
-        hasher.Write(content)
-        filename := hex.EncodeToString(hasher.Sum(nil))
-
-        fmt.Printf("file: %s\n", filename)
-
-        err = oneDriveClient.UploadFile("test/test1/" + filename, content, 100)
-        if err != nil {
-            /*if e, ok := err.(ACDError); !ok || e.Status != 409 */ {
-                t.Errorf("Failed to upload the file %s: %v", filename, err)
-                return
-            }
-        }
-    }
-
-    entries, err := oneDriveClient.ListEntries("test/test1")
-    if err != nil {
-        t.Errorf("Error list randomly generated files: %v", err)
-        return
-    }
-
-    for _, entry := range entries {
-        err = oneDriveClient.MoveFile("test/test1/" + entry.Name, "test/test2")
-        if err != nil {
-            t.Errorf("Failed to move %s: %v", entry.Name, err)
-            return
-        }
-    }
-
-    entries, err = oneDriveClient.ListEntries("test/test2")
-    if err != nil {
-        t.Errorf("Error list randomly generated files: %v", err)
-        return
-    }
-
-    for _, entry := range entries {
-        readCloser, _, err := oneDriveClient.DownloadFile("test/test2/" + entry.Name)
-        if err != nil {
-            t.Errorf("Error downloading file %s: %v", entry.Name, err)
-            return
-        }
-
-        hasher := sha256.New()
-        io.Copy(hasher, readCloser)
-        hash := hex.EncodeToString(hasher.Sum(nil))
-
-        if hash != entry.Name {
-            t.Errorf("File %s, hash %s", entry.Name, hash)
-        }
-
-        readCloser.Close()
-    }
-
-    for _, entry := range entries {
-
-        err = oneDriveClient.DeleteFile("test/test2/" + entry.Name)
-        if err != nil {
-            t.Errorf("Failed to delete the file %s: %v", entry.Name, err)
-            return
-        }
-    }
-
-}

src/duplicacy_onestorage.go

@@ -11,7 +11,7 @@ import (
 )
 
 type OneDriveStorage struct {
-    RateLimitedStorage
+	StorageBase
 
 	client         *OneDriveClient
 	storageDir     string
@@ -19,13 +19,13 @@ type OneDriveStorage struct {
 }
 
 // CreateOneDriveStorage creates an OneDrive storage object.
-func CreateOneDriveStorage(tokenFile string, storagePath string, threads int) (storage *OneDriveStorage, err error) {
+func CreateOneDriveStorage(tokenFile string, isBusiness bool, storagePath string, threads int, client_id string, client_secret string, drive_id string) (storage *OneDriveStorage, err error) {
 
 	for len(storagePath) > 0 && storagePath[len(storagePath)-1] == '/' {
 		storagePath = storagePath[:len(storagePath)-1]
 	}
 
-    client, err := NewOneDriveClient(tokenFile)
+	client, err := NewOneDriveClient(tokenFile, isBusiness, client_id, client_secret, drive_id)
 	if err != nil {
 		return nil, err
 	}
@@ -65,12 +65,22 @@ func CreateOneDriveStorage(tokenFile string, storagePath string, threads int) (s
 		}
 	}
 
+	storage.DerivedStorage = storage
+	storage.SetDefaultNestingLevels([]int{0}, 0)
 	return storage, nil
 
 }
 
+func (storage *OneDriveStorage) convertFilePath(filePath string) string {
+	if strings.HasPrefix(filePath, "chunks/") && strings.HasSuffix(filePath, ".fsl") {
+		return "fossils/" + filePath[len("chunks/"):len(filePath)-len(".fsl")]
+	}
+	return filePath
+}
+
 // ListFiles return the list of files and subdirectories under 'dir' (non-recursively)
 func (storage *OneDriveStorage) ListFiles(threadIndex int, dir string) ([]string, []int64, error) {
+
 	for len(dir) > 0 && dir[len(dir)-1] == '/' {
 		dir = dir[:len(dir)-1]
 	}
@@ -88,7 +98,7 @@ func (storage *OneDriveStorage) ListFiles(threadIndex int, dir string) ([]string
 			}
 		}
 		return subDirs, nil, nil
-    } else if strings.HasPrefix(dir, "snapshots/") {
+	} else if strings.HasPrefix(dir, "snapshots/") || strings.HasPrefix(dir, "benchmark") {
 		entries, err := storage.client.ListEntries(storage.storageDir + "/" + dir)
 		if err != nil {
 			return nil, nil, err
@@ -105,19 +115,29 @@ func (storage *OneDriveStorage) ListFiles(threadIndex int, dir string) ([]string
 	} else {
 		files := []string{}
 		sizes := []int64{}
-        for _, parent := range []string {"chunks", "fossils" } {
+		parents := []string{"chunks", "fossils"}
+		for i := 0; i < len(parents); i++ {
+			parent := parents[i]
 			entries, err := storage.client.ListEntries(storage.storageDir + "/" + parent)
 			if err != nil {
 				return nil, nil, err
 			}
 
 			for _, entry := range entries {
+				if len(entry.Folder) == 0 {
 					name := entry.Name
-                if parent == "fossils" {
-                    name += ".fsl"
+					if strings.HasPrefix(parent, "fossils") {
+						name = parent + "/" + name + ".fsl"
+						name = name[len("fossils/"):]
+					} else {
+						name = parent + "/" + name
+						name = name[len("chunks/"):]
 					}
 					files = append(files, name)
 					sizes = append(sizes, entry.Size)
+				} else {
+					parents = append(parents, parent+"/"+entry.Name)
+				}
 			}
 		}
 		return files, sizes, nil
@@ -127,9 +147,7 @@ func (storage *OneDriveStorage) ListFiles(threadIndex int, dir string) ([]string
 
 // DeleteFile deletes the file or directory at 'filePath'.
 func (storage *OneDriveStorage) DeleteFile(threadIndex int, filePath string) (err error) {
-    if strings.HasSuffix(filePath, ".fsl") && strings.HasPrefix(filePath, "chunks/") {
-        filePath = "fossils/" + filePath[len("chunks/"):len(filePath) - len(".fsl")]
-    }
+	filePath = storage.convertFilePath(filePath)
 
 	err = storage.client.DeleteFile(storage.storageDir + "/" + filePath)
 	if e, ok := err.(OneDriveError); ok && e.Status == 404 {
@@ -141,14 +159,11 @@ func (storage *OneDriveStorage) DeleteFile(threadIndex int, filePath string) (er
 
 // MoveFile renames the file.
 func (storage *OneDriveStorage) MoveFile(threadIndex int, from string, to string) (err error) {
-    fromPath := storage.storageDir + "/" + from
-    toParent := storage.storageDir + "/fossils"
-    if strings.HasSuffix(from, ".fsl") {
-        fromPath = storage.storageDir + "/fossils/" + from[len("chunks/"):len(from) - len(".fsl")]
-        toParent = storage.storageDir + "/chunks"
-    }
 
-    err = storage.client.MoveFile(fromPath, toParent)
+	fromPath := storage.storageDir + "/" + storage.convertFilePath(from)
+	toPath := storage.storageDir + "/" + storage.convertFilePath(to)
+
+	err = storage.client.MoveFile(fromPath, path.Dir(toPath))
 	if err != nil {
 		if e, ok := err.(OneDriveError); ok && e.Status == 409 {
 			LOG_DEBUG("ONEDRIVE_MOVE", "Ignore 409 conflict error")
@@ -180,24 +195,13 @@ func (storage *OneDriveStorage) GetFileInfo(threadIndex int, filePath string) (e
 	for len(filePath) > 0 && filePath[len(filePath)-1] == '/' {
 		filePath = filePath[:len(filePath)-1]
 	}
+
+	filePath = storage.convertFilePath(filePath)
+
 	fileID, isDir, size, err := storage.client.GetFileInfo(storage.storageDir + "/" + filePath)
 	return fileID != "", isDir, size, err
 }
 
-// FindChunk finds the chunk with the specified id.  If 'isFossil' is true, it will search for chunk files with
-// the suffix '.fsl'.
-func (storage *OneDriveStorage) FindChunk(threadIndex int, chunkID string, isFossil bool) (filePath string, exist bool, size int64, err error) {
-    filePath = "chunks/" + chunkID
-    realPath := storage.storageDir + "/" + filePath
-    if isFossil {
-        filePath += ".fsl"
-        realPath = storage.storageDir + "/fossils/" + chunkID
-    }
-
-    fileID, _, size, err := storage.client.GetFileInfo(realPath)
-    return filePath, fileID != "", size, err
-}
-
 // DownloadFile reads the file at 'filePath' into the chunk.
 func (storage *OneDriveStorage) DownloadFile(threadIndex int, filePath string, chunk *Chunk) (err error) {
 	readCloser, _, err := storage.client.DownloadFile(storage.storageDir + "/" + filePath)
@@ -225,16 +229,16 @@ func (storage *OneDriveStorage) UploadFile(threadIndex int, filePath string, con
 
 // If a local snapshot cache is needed for the storage to avoid downloading/uploading chunks too often when
 // managing snapshots.
-func (storage *OneDriveStorage) IsCacheNeeded() (bool) { return true }
+func (storage *OneDriveStorage) IsCacheNeeded() bool { return true }
 
 // If the 'MoveFile' method is implemented.
-func (storage *OneDriveStorage) IsMoveFileImplemented() (bool) { return true }
+func (storage *OneDriveStorage) IsMoveFileImplemented() bool { return true }
 
 // If the storage can guarantee strong consistency.
-func (storage *OneDriveStorage) IsStrongConsistent() (bool) { return false }
+func (storage *OneDriveStorage) IsStrongConsistent() bool { return false }
 
 // If the storage supports fast listing of files names.
-func (storage *OneDriveStorage) IsFastListing() (bool) { return true }
+func (storage *OneDriveStorage) IsFastListing() bool { return true }
 
 // Enable the test mode.
 func (storage *OneDriveStorage) EnableTestMode() {

src/duplicacy_preference.go

@@ -6,22 +6,27 @@ package duplicacy
 
 import (
 	"encoding/json"
-    "path"
 	"io/ioutil"
-    "reflect"
 	"os"
+	"path"
+	"reflect"
+	"strings"
 )
 
 // Preference stores options for each storage.
 type Preference struct {
 	Name              string            `json:"name"`
 	SnapshotID        string            `json:"id"`
+	RepositoryPath    string            `json:"repository"`
 	StorageURL        string            `json:"storage"`
 	Encrypted         bool              `json:"encrypted"`
 	BackupProhibited  bool              `json:"no_backup"`
 	RestoreProhibited bool              `json:"no_restore"`
 	DoNotSavePassword bool              `json:"no_save_password"`
+	NobackupFile      string            `json:"nobackup_file"`
 	Keys              map[string]string `json:"keys"`
+	FiltersFile       string            `json:"filters"`
+	ExcludeByAttribute bool             `json:"exclude_by_attribute"`
 }
 
 var preferencePath string
@@ -43,7 +48,7 @@ func LoadPreferences(repository string) bool {
 			LOG_ERROR("DOT_DUPLICACY_PATH", "Failed to locate the preference path: %v", err)
 			return false
 		}
-        realPreferencePath := string(content)
+		realPreferencePath := strings.TrimSpace(string(content))
 		stat, err := os.Stat(realPreferencePath)
 		if err != nil {
 			LOG_ERROR("PREFERENCE_PATH", "Failed to retrieve the information about the directory %s: %v", content, err)
@@ -73,6 +78,13 @@ func LoadPreferences(repository string) bool {
 		return false
 	}
 
+	for _, preference := range Preferences {
+		if strings.ToLower(preference.Name) == "ssh" {
+			LOG_ERROR("PREFERENCE_INVALID", "'%s' is an invalid storage name", preference.Name)
+			return false
+		}
+	}
+
 	return true
 }
 
@@ -90,7 +102,7 @@ func SetDuplicacyPreferencePath(p string) {
 	preferencePath = p
 }
 
-func SavePreferences() (bool) {
+func SavePreferences() bool {
 	description, err := json.MarshalIndent(Preferences, "", "    ")
 	if err != nil {
 		LOG_ERROR("PREFERENCE_MARSHAL", "Failed to marshal the repository preferences: %v", err)
@@ -98,7 +110,7 @@ func SavePreferences() (bool) {
 	}
 	preferenceFile := path.Join(GetDuplicacyPreferencePath(), "preferences")
 
-    err = ioutil.WriteFile(preferenceFile, description, 0644)
+	err = ioutil.WriteFile(preferenceFile, description, 0600)
 	if err != nil {
 		LOG_ERROR("PREFERENCE_WRITE", "Failed to save the preference file %s: %v", preferenceFile, err)
 		return false
@@ -107,10 +119,10 @@ func SavePreferences() (bool) {
 	return true
 }
 
-func FindPreference(name string) (*Preference) {
-    for _, preference := range Preferences {
+func FindPreference(name string) *Preference {
+	for i, preference := range Preferences {
 		if preference.Name == name || preference.StorageURL == name {
-            return &preference
+			return &Preferences[i]
 		}
 	}
 

src/duplicacy_s3cstorage.go

@@ -6,13 +6,14 @@ package duplicacy
 
 import (
 	"time"
+
 	"github.com/gilbertchen/goamz/aws"
 	"github.com/gilbertchen/goamz/s3"
 )
 
 // S3CStorage is a storage backend for s3 compatible storages that require V2 Signing.
 type S3CStorage struct {
-    RateLimitedStorage
+	StorageBase
 
 	buckets    []*s3.Bucket
 	storageDir string
@@ -57,6 +58,8 @@ func CreateS3CStorage(regionName string, endpoint string, bucketName string, sto
 		storageDir: storageDir,
 	}
 
+	storage.DerivedStorage = storage
+	storage.SetDefaultNestingLevels([]int{0}, 0)
 	return storage, nil
 }
 
@@ -153,25 +156,6 @@ func (storage *S3CStorage) GetFileInfo(threadIndex int, filePath string) (exist
 	}
 }
 
-// FindChunk finds the chunk with the specified id.  If 'isFossil' is true, it will search for chunk files with
-// the suffix '.fsl'.
-func (storage *S3CStorage) FindChunk(threadIndex int, chunkID string, isFossil bool) (filePath string, exist bool, size int64, err error) {
-
-    filePath = "chunks/" + chunkID
-    if isFossil {
-        filePath += ".fsl"
-    }
-
-    exist, _, size, err = storage.GetFileInfo(threadIndex, filePath)
-
-    if err != nil {
-        return "", false, 0, err
-    } else {
-        return filePath, exist, size, err
-    }
-
-}
-
 // DownloadFile reads the file at 'filePath' into the chunk.
 func (storage *S3CStorage) DownloadFile(threadIndex int, filePath string, chunk *Chunk) (err error) {
 
@@ -197,16 +181,16 @@ func (storage *S3CStorage) UploadFile(threadIndex int, filePath string, content
 
 // If a local snapshot cache is needed for the storage to avoid downloading/uploading chunks too often when
 // managing snapshots.
-func (storage *S3CStorage) IsCacheNeeded () (bool) { return true }
+func (storage *S3CStorage) IsCacheNeeded() bool { return true }
 
 // If the 'MoveFile' method is implemented.
-func (storage *S3CStorage) IsMoveFileImplemented() (bool) { return true }
+func (storage *S3CStorage) IsMoveFileImplemented() bool { return true }
 
 // If the storage can guarantee strong consistency.
-func (storage *S3CStorage) IsStrongConsistent() (bool) { return false }
+func (storage *S3CStorage) IsStrongConsistent() bool { return false }
 
 // If the storage supports fast listing of files names.
-func (storage *S3CStorage) IsFastListing() (bool) { return true }
+func (storage *S3CStorage) IsFastListing() bool { return true }
 
 // Enable the test mode.
 func (storage *S3CStorage) EnableTestMode() {}

src/duplicacy_s3storage.go

@@ -2,9 +2,17 @@
 // Free for personal use and commercial trial
 // Commercial use requires per-user licenses available from https://duplicacy.com
 
+// NOTE: The code in the Wasabi storage module relies on all functions
+// in this one except MoveFile(), IsMoveFileImplemented() and
+// IsStrongConsistent().  Changes to the API here will need to be
+// reflected there.
+
 package duplicacy
 
 import (
+	"reflect"
+	"strings"
+
 	"github.com/aws/aws-sdk-go/aws"
 	"github.com/aws/aws-sdk-go/aws/awserr"
 	"github.com/aws/aws-sdk-go/aws/credentials"
@@ -13,7 +21,7 @@ import (
 )
 
 type S3Storage struct {
-    RateLimitedStorage
+	StorageBase
 
 	client          *s3.S3
 	bucket          string
@@ -50,7 +58,7 @@ func CreateS3Storage(regionName string, endpoint string, bucketName string, stor
 		}
 	}
 
-    config := &aws.Config {
+	s3Config := &aws.Config{
 		Region:           aws.String(regionName),
 		Credentials:      auth,
 		Endpoint:         aws.String(endpoint),
@@ -63,12 +71,14 @@ func CreateS3Storage(regionName string, endpoint string, bucketName string, stor
 	}
 
 	storage = &S3Storage{
-        client: s3.New(session.New(config)),
+		client:          s3.New(session.New(s3Config)),
 		bucket:          bucketName,
 		storageDir:      storageDir,
 		numberOfThreads: threads,
 	}
 
+	storage.DerivedStorage = storage
+	storage.SetDefaultNestingLevels([]int{0}, 0)
 	return storage, nil
 }
 
@@ -185,25 +195,6 @@ func (storage *S3Storage) GetFileInfo(threadIndex int, filePath string) (exist b
 	}
 }
 
-// FindChunk finds the chunk with the specified id.  If 'isFossil' is true, it will search for chunk files with
-// the suffix '.fsl'.
-func (storage *S3Storage) FindChunk(threadIndex int, chunkID string, isFossil bool) (filePath string, exist bool, size int64, err error) {
-
-    filePath = "chunks/" + chunkID
-    if isFossil {
-        filePath += ".fsl"
-    }
-
-    exist, _, size, err = storage.GetFileInfo(threadIndex, filePath)
-
-    if err != nil {
-        return "", false, 0, err
-    } else {
-        return filePath, exist, size, err
-    }
-
-}
-
 // DownloadFile reads the file at 'filePath' into the chunk.
 func (storage *S3Storage) DownloadFile(threadIndex int, filePath string, chunk *Chunk) (err error) {
 
@@ -219,7 +210,7 @@ func (storage *S3Storage) DownloadFile(threadIndex int, filePath string, chunk *
 
 	defer output.Body.Close()
 
-    _, err = RateLimitedCopy(chunk, output.Body, storage.DownloadRateLimit / len(storage.bucket))
+	_, err = RateLimitedCopy(chunk, output.Body, storage.DownloadRateLimit/storage.numberOfThreads)
 	return err
 
 }
@@ -227,30 +218,39 @@ func (storage *S3Storage) DownloadFile(threadIndex int, filePath string, chunk *
 // UploadFile writes 'content' to the file at 'filePath'.
 func (storage *S3Storage) UploadFile(threadIndex int, filePath string, content []byte) (err error) {
 
+	attempts := 0
+
+	for {
 		input := &s3.PutObjectInput{
 			Bucket:      aws.String(storage.bucket),
 			Key:         aws.String(storage.storageDir + filePath),
 			ACL:         aws.String(s3.ObjectCannedACLPrivate),
-        Body: CreateRateLimitedReader(content, storage.UploadRateLimit / len(storage.bucket)),
+			Body:        CreateRateLimitedReader(content, storage.UploadRateLimit/storage.numberOfThreads),
 			ContentType: aws.String("application/duplicacy"),
 		}
 
 		_, err = storage.client.PutObject(input)
+		if err == nil || attempts >= 3 || !strings.Contains(err.Error(), "XAmzContentSHA256Mismatch") {
 			return err
 		}
 
+		LOG_INFO("S3_RETRY", "Retrying on %s: %v", reflect.TypeOf(err), err)
+		attempts += 1
+	}
+}
+
 // If a local snapshot cache is needed for the storage to avoid downloading/uploading chunks too often when
 // managing snapshots.
-func (storage *S3Storage) IsCacheNeeded () (bool) { return true }
+func (storage *S3Storage) IsCacheNeeded() bool { return true }
 
 // If the 'MoveFile' method is implemented.
-func (storage *S3Storage) IsMoveFileImplemented() (bool) { return true }
+func (storage *S3Storage) IsMoveFileImplemented() bool { return true }
 
 // If the storage can guarantee strong consistency.
-func (storage *S3Storage) IsStrongConsistent() (bool) { return false }
+func (storage *S3Storage) IsStrongConsistent() bool { return false }
 
 // If the storage supports fast listing of files names.
-func (storage *S3Storage) IsFastListing() (bool) { return true }
+func (storage *S3Storage) IsFastListing() bool { return true }
 
 // Enable the test mode.
 func (storage *S3Storage) EnableTestMode() {}

src/duplicacy_sambastorage.go

@@ -0,0 +1,250 @@
+// Copyright (c) Acrosync LLC. All rights reserved.
+// Free for personal use and commercial trial
+// Commercial use requires per-user licenses available from https://duplicacy.com
+
+package duplicacy
+
+import (
+	"io"
+	"os"
+	"fmt"
+	"net"
+	"path"
+	"time"
+	"strings"
+	"syscall"
+	"math/rand"
+
+	"github.com/hirochachacha/go-smb2"
+)
+
+// SambaStorage is a local on-disk file storage implementing the Storage interface.
+type SambaStorage struct {
+	StorageBase
+
+	share           *smb2.Share
+	storageDir      string
+	numberOfThreads int
+}
+
+// CreateSambaStorage creates a file storage.
+func CreateSambaStorage(server string, port int, username string, password string, shareName string, storageDir string, threads int) (storage *SambaStorage, err error) {
+
+	connection, err := net.Dial("tcp", fmt.Sprintf("%s:%d", server, port))
+	if err != nil {
+		return nil, err
+	}
+
+	dialer := &smb2.Dialer{
+		Initiator: &smb2.NTLMInitiator{
+			User:     username,
+			Password: password,
+		},
+	}
+
+	client, err := dialer.Dial(connection)
+	if err != nil {
+		return nil, err
+	}
+
+	share, err := client.Mount(shareName)
+	if err != nil {
+		return nil, err
+	}
+
+	// Random number fo generating the temporary chunk file suffix.
+	rand.Seed(time.Now().UnixNano())
+
+	storage = &SambaStorage{
+		share:           share,
+		numberOfThreads: threads,
+	}
+
+	exist, isDir, _, err := storage.GetFileInfo(0, storageDir)
+	if err != nil {
+		return nil, fmt.Errorf("Failed to check the storage path %s: %v", storageDir, err)
+	}
+
+	if !exist {
+		return nil, fmt.Errorf("The storage path %s does not exist", storageDir)
+	}
+
+	if !isDir {
+		return nil, fmt.Errorf("The storage path %s is not a directory", storageDir)
+	}
+
+	storage.storageDir = storageDir
+	storage.DerivedStorage = storage
+	storage.SetDefaultNestingLevels([]int{2, 3}, 2)
+	return storage, nil
+}
+
+// ListFiles return the list of files and subdirectories under 'dir' (non-recursively).
+func (storage *SambaStorage) ListFiles(threadIndex int, dir string) (files []string, sizes []int64, err error) {
+
+	fullPath := path.Join(storage.storageDir, dir)
+
+	list, err := storage.share.ReadDir(fullPath)
+	if err != nil {
+		if os.IsNotExist(err) {
+			return nil, nil, nil
+		}
+		return nil, nil, err
+	}
+
+	for _, f := range list {
+		name := f.Name()
+		if (f.IsDir() || f.Mode() & os.ModeSymlink != 0) && name[len(name)-1] != '/' {
+			name += "/"
+		}
+		files = append(files, name)
+		sizes = append(sizes, f.Size())
+	}
+
+	return files, sizes, nil
+}
+
+// DeleteFile deletes the file or directory at 'filePath'.
+func (storage *SambaStorage) DeleteFile(threadIndex int, filePath string) (err error) {
+	err = storage.share.Remove(path.Join(storage.storageDir, filePath))
+	if err == nil || os.IsNotExist(err) {
+		return nil
+	} else {
+		return err
+	}
+}
+
+// MoveFile renames the file.
+func (storage *SambaStorage) MoveFile(threadIndex int, from string, to string) (err error) {
+	return storage.share.Rename(path.Join(storage.storageDir, from), path.Join(storage.storageDir, to))
+}
+
+// CreateDirectory creates a new directory.
+func (storage *SambaStorage) CreateDirectory(threadIndex int, dir string) (err error) {
+	fmt.Printf("Creating directory %s\n", dir)
+	err = storage.share.Mkdir(path.Join(storage.storageDir, dir), 0744)
+	if err != nil && os.IsExist(err) {
+		return nil
+	} else {
+		return err
+	}
+}
+
+// GetFileInfo returns the information about the file or directory at 'filePath'.
+func (storage *SambaStorage) GetFileInfo(threadIndex int, filePath string) (exist bool, isDir bool, size int64, err error) {
+	stat, err := storage.share.Stat(path.Join(storage.storageDir, filePath))
+	if err != nil {
+		if os.IsNotExist(err) {
+			return false, false, 0, nil
+		} else {
+			return false, false, 0, err
+		}
+	}
+
+	return true, stat.IsDir(), stat.Size(), nil
+}
+
+// DownloadFile reads the file at 'filePath' into the chunk.
+func (storage *SambaStorage) DownloadFile(threadIndex int, filePath string, chunk *Chunk) (err error) {
+
+	file, err := storage.share.Open(path.Join(storage.storageDir, filePath))
+
+	if err != nil {
+		return err
+	}
+
+	defer file.Close()
+	if _, err = RateLimitedCopy(chunk, file, storage.DownloadRateLimit/storage.numberOfThreads); err != nil {
+		return err
+	}
+
+	return nil
+
+}
+
+// UploadFile writes 'content' to the file at 'filePath'
+func (storage *SambaStorage) UploadFile(threadIndex int, filePath string, content []byte) (err error) {
+
+	fullPath := path.Join(storage.storageDir, filePath)
+
+	if len(strings.Split(filePath, "/")) > 2 {
+		dir := path.Dir(fullPath)
+		stat, err := storage.share.Stat(dir)
+		if err != nil {
+			if !os.IsNotExist(err) {
+				return err
+			}
+			err = storage.share.MkdirAll(dir, 0744)
+			if err != nil {
+				return err
+			}
+		} else {
+			if !stat.IsDir() && stat.Mode() & os.ModeSymlink == 0 {
+				return fmt.Errorf("The path %s is not a directory or symlink", dir)
+			}
+		}
+	}
+
+	letters := "abcdefghijklmnopqrstuvwxyz"
+	suffix := make([]byte, 8)
+	for i := range suffix {
+		suffix[i] = letters[rand.Intn(len(letters))]
+	}
+
+	temporaryFile := fullPath + "." + string(suffix) + ".tmp"
+
+	file, err := storage.share.Create(temporaryFile)
+	if err != nil {
+		return err
+	}
+
+	reader := CreateRateLimitedReader(content, storage.UploadRateLimit/storage.numberOfThreads)
+	_, err = io.Copy(file, reader)
+	if err != nil {
+		file.Close()
+		return err
+	}
+
+	if err = file.Sync(); err != nil {
+		pathErr, ok := err.(*os.PathError)
+		isNotSupported := ok && pathErr.Op == "sync" && pathErr.Err == syscall.ENOTSUP
+		if !isNotSupported {
+			_ = file.Close()
+			return err
+		}
+	}
+
+	err = file.Close()
+	if err != nil {
+		return err
+	}
+
+	err = storage.share.Rename(temporaryFile, fullPath)
+	if err != nil {
+
+		if _, e := storage.share.Stat(fullPath); e == nil {
+			storage.share.Remove(temporaryFile)
+			return nil
+		} else {
+			return err
+		}
+	}
+
+	return nil
+}
+
+// If a local snapshot cache is needed for the storage to avoid downloading/uploading chunks too often when
+// managing snapshots.
+func (storage *SambaStorage) IsCacheNeeded() bool { return true }
+
+// If the 'MoveFile' method is implemented.
+func (storage *SambaStorage) IsMoveFileImplemented() bool { return true }
+
+// If the storage can guarantee strong consistency.
+func (storage *SambaStorage) IsStrongConsistent() bool { return true }
+
+// If the storage supports fast listing of files names.
+func (storage *SambaStorage) IsFastListing() bool { return false }
+
+// Enable the test mode.
+func (storage *SambaStorage) EnableTestMode() {}

src/duplicacy_sftpstorage.go

@@ -7,56 +7,75 @@ package duplicacy
 import (
 	"fmt"
 	"io"
-    "os"
-    "net"
-    "path"
-    "time"
-    "runtime"
 	"math/rand"
+	"net"
+	"os"
+	"path"
+	"runtime"
+	"strings"
+	"time"
+	"sync"
 
-    "golang.org/x/crypto/ssh"
 	"github.com/pkg/sftp"
+	"golang.org/x/crypto/ssh"
 )
 
 type SFTPStorage struct {
-    RateLimitedStorage
+	StorageBase
 
 	client          *sftp.Client
+	clientLock      sync.Mutex
+	minimumNesting  int // The minimum level of directories to dive into before searching for the chunk file.
 	storageDir      string
 	numberOfThreads int
+	numberOfTries   int
+	serverAddress   string
+	sftpConfig      *ssh.ClientConfig
 }
 
 func CreateSFTPStorageWithPassword(server string, port int, username string, storageDir string,
-                                   password string, threads int) (storage *SFTPStorage, err error) {
+	minimumNesting int, password string, threads int) (storage *SFTPStorage, err error) {
 
 	authMethods := []ssh.AuthMethod{ssh.Password(password)}
 
-
 	hostKeyCallback := func(hostname string, remote net.Addr,
 		key ssh.PublicKey) error {
 		return nil
 	}
 
-    return CreateSFTPStorage(server, port, username, storageDir, authMethods, hostKeyCallback, threads)
+	return CreateSFTPStorage(false, server, port, username, storageDir, minimumNesting, authMethods, hostKeyCallback, threads)
 }
 
-func CreateSFTPStorage(server string, port int, username string, storageDir string,
+func CreateSFTPStorage(compatibilityMode bool, server string, port int, username string, storageDir string, minimumNesting int,
 	authMethods []ssh.AuthMethod,
 	hostKeyCallback func(hostname string, remote net.Addr,
 		key ssh.PublicKey) error, threads int) (storage *SFTPStorage, err error) {
 
-    config := &ssh.ClientConfig{
+	sftpConfig := &ssh.ClientConfig{
 		User:            username,
 		Auth:            authMethods,
 		HostKeyCallback: hostKeyCallback,
 	}
 
-    if server == "sftp.hidrive.strato.com" {
-        config.Ciphers = []string {"aes128-cbc", "aes128-ctr", "aes256-ctr"}
+	if compatibilityMode {
+		sftpConfig.Ciphers = []string{
+			"aes128-ctr", "aes192-ctr", "aes256-ctr",
+			"aes128-gcm@openssh.com",
+			"chacha20-poly1305@openssh.com",
+			"arcfour256", "arcfour128", "arcfour",
+			"aes128-cbc",
+			"3des-cbc",
+		}
+		sftpConfig.KeyExchanges = [] string {
+			"curve25519-sha256@libssh.org",
+			"ecdh-sha2-nistp256", "ecdh-sha2-nistp384", "ecdh-sha2-nistp521",
+			"diffie-hellman-group1-sha1", "diffie-hellman-group14-sha1",
+			"diffie-hellman-group-exchange-sha1", "diffie-hellman-group-exchange-sha256",
+		}
 	}
 
 	serverAddress := fmt.Sprintf("%s:%d", server, port)
-    connection, err := ssh.Dial("tcp", serverAddress, config)
+	connection, err := ssh.Dial("tcp", serverAddress, sftpConfig)
 	if err != nil {
 		return nil, err
 	}
@@ -83,7 +102,11 @@ func CreateSFTPStorage(server string, port int, username string, storageDir stri
 	storage = &SFTPStorage{
 		client:          client,
 		storageDir:      storageDir,
+		minimumNesting:  minimumNesting,
 		numberOfThreads: threads,
+		numberOfTries:   8,
+		serverAddress:   serverAddress,
+		sftpConfig:      sftpConfig,
 	}
 
 	// Random number fo generating the temporary chunk file suffix.
@@ -91,17 +114,63 @@ func CreateSFTPStorage(server string, port int, username string, storageDir stri
 
 	runtime.SetFinalizer(storage, CloseSFTPStorage)
 
+	storage.DerivedStorage = storage
+	storage.SetDefaultNestingLevels([]int{2, 3}, 2)
 	return storage, nil
 }
 
 func CloseSFTPStorage(storage *SFTPStorage) {
+	if storage.client != nil {
 		storage.client.Close()
+		storage.client = nil
+	}
 }
 
+func (storage *SFTPStorage) getSFTPClient() *sftp.Client {
+	storage.clientLock.Lock()
+	defer storage.clientLock.Unlock()
+	return storage.client
+}
+
+func (storage *SFTPStorage) retry(f func () error) error {
+	delay := time.Second
+	for i := 0;; i++ {
+		err := f()
+		if err != nil && strings.Contains(err.Error(), "EOF") && i < storage.numberOfTries {
+			LOG_WARN("SFTP_RETRY", "Encountered an error (%v); retry after %d second(s)", err, delay/time.Second)
+			time.Sleep(delay)
+			delay *= 2
+
+			storage.clientLock.Lock()
+			connection, err := ssh.Dial("tcp", storage.serverAddress, storage.sftpConfig)
+			if err != nil {
+				LOG_WARN("SFTP_RECONNECT", "Failed to connect to %s: %v; retrying", storage.serverAddress, err)
+				storage.clientLock.Unlock()
+				continue
+			}
+
+			client, err := sftp.NewClient(connection)
+			if err != nil {
+				LOG_WARN("SFTP_RECONNECT", "Failed to create a new SFTP client to %s: %v; retrying", storage.serverAddress, err)
+				connection.Close()
+				storage.clientLock.Unlock()
+				continue
+			}
+			storage.client = client
+			storage.clientLock.Unlock()
+			continue
+		}
+		return err
+	}
+}
 // ListFiles return the list of files and subdirectories under 'file' (non-recursively)
 func (storage *SFTPStorage) ListFiles(threadIndex int, dirPath string) (files []string, sizes []int64, err error) {
 
-    entries, err := storage.client.ReadDir(path.Join(storage.storageDir, dirPath))
+	var entries []os.FileInfo
+	err = storage.retry(func() error {
+		entries, err = storage.getSFTPClient().ReadDir(path.Join(storage.storageDir, dirPath))
+		return err
+	})
 	if err != nil {
 		return nil, nil, err
 	}
@@ -122,7 +191,11 @@ func (storage *SFTPStorage) ListFiles(threadIndex int, dirPath string) (files []
 // DeleteFile deletes the file or directory at 'filePath'.
 func (storage *SFTPStorage) DeleteFile(threadIndex int, filePath string) (err error) {
 	fullPath := path.Join(storage.storageDir, filePath)
-    fileInfo, err := storage.client.Stat(fullPath)
+	var fileInfo os.FileInfo
+	err = storage.retry(func() error {
+		fileInfo, err = storage.getSFTPClient().Stat(fullPath)
+		return err
+	})
 	if err != nil {
 		if os.IsNotExist(err) {
 			LOG_TRACE("SFTP_STORAGE", "File %s has disappeared before deletion", filePath)
@@ -133,33 +206,47 @@ func (storage *SFTPStorage) DeleteFile(threadIndex int, filePath string) (err er
 	if fileInfo == nil {
 		return nil
 	}
-    return storage.client.Remove(path.Join(storage.storageDir, filePath))
+	return storage.retry(func() error { return storage.getSFTPClient().Remove(path.Join(storage.storageDir, filePath)) })
 }
 
 // MoveFile renames the file.
 func (storage *SFTPStorage) MoveFile(threadIndex int, from string, to string) (err error) {
 	toPath := path.Join(storage.storageDir, to)
-    fileInfo, err := storage.client.Stat(toPath)
+	var fileInfo os.FileInfo
+	err = storage.retry(func() error {
+		fileInfo, err = storage.getSFTPClient().Stat(toPath)
+		return err
+	})
 	if fileInfo != nil {
 		return fmt.Errorf("The destination file %s already exists", toPath)
 	}
-    return storage.client.Rename(path.Join(storage.storageDir, from),
-                                 path.Join(storage.storageDir, to))
+	err = storage.retry(func() error { return storage.getSFTPClient().Rename(path.Join(storage.storageDir, from),
+		path.Join(storage.storageDir, to)) })
+	return err
 }
 
 // CreateDirectory creates a new directory.
 func (storage *SFTPStorage) CreateDirectory(threadIndex int, dirPath string) (err error) {
 	fullPath := path.Join(storage.storageDir, dirPath)
-    fileInfo, err := storage.client.Stat(fullPath)
+	var fileInfo os.FileInfo
+	err = storage.retry(func() error {
+		fileInfo, err = storage.getSFTPClient().Stat(fullPath)
+		return err
+	})
 	if fileInfo != nil && fileInfo.IsDir() {
 		return nil
 	}
-    return storage.client.Mkdir(path.Join(storage.storageDir, dirPath))
+	return storage.retry(func() error { return storage.getSFTPClient().Mkdir(path.Join(storage.storageDir, dirPath)) })
 }
 
 // GetFileInfo returns the information about the file or directory at 'filePath'.
 func (storage *SFTPStorage) GetFileInfo(threadIndex int, filePath string) (exist bool, isDir bool, size int64, err error) {
-    fileInfo, err := storage.client.Stat(path.Join(storage.storageDir, filePath))
+	var fileInfo os.FileInfo
+	err = storage.retry(func() error {
+		fileInfo, err = storage.getSFTPClient().Stat(path.Join(storage.storageDir, filePath))
+		return err
+	})
+
 	if err != nil {
 		if os.IsNotExist(err) {
 			return false, false, 0, nil
@@ -175,70 +262,10 @@ func (storage *SFTPStorage) GetFileInfo(threadIndex int, filePath string) (exist
 	return true, fileInfo.IsDir(), fileInfo.Size(), nil
 }
 
-// FindChunk finds the chunk with the specified id.  If 'isFossil' is true, it will search for chunk files with
-// the suffix '.fsl'.
-func (storage *SFTPStorage) FindChunk(threadIndex int, chunkID string, isFossil bool) (filePath string, exist bool, size int64, err error) {
-     dir := path.Join(storage.storageDir, "chunks")
-
-    suffix := ""
-    if isFossil {
-        suffix = ".fsl"
-    }
-
-    // The minimum level of directories to dive into before searching for the chunk file.
-    minimumLevel := 2
-
-    for level := 0; level * 2 < len(chunkID); level ++ {
-        if level >= minimumLevel {
-            filePath = path.Join(dir, chunkID[2 * level:]) + suffix
-            if stat, err := storage.client.Stat(filePath); err == nil && !stat.IsDir() {
-                return filePath[len(storage.storageDir) + 1:], true, stat.Size(), nil
-            } else if err == nil && stat.IsDir() {
-                return filePath[len(storage.storageDir) + 1:], true, 0, fmt.Errorf("The path %s is a directory", filePath)
-            }
-        }
-
-        // Find the subdirectory the chunk file may reside.
-        subDir := path.Join(dir, chunkID[2 * level: 2 * level + 2])
-        stat, err := storage.client.Stat(subDir)
-        if err == nil && stat.IsDir() {
-            dir = subDir
-            continue
-        }
-
-        if level < minimumLevel {
-            // Create the subdirectory if is doesn't exist.
-
-            if err == nil && !stat.IsDir() {
-                return "", false, 0, fmt.Errorf("The path %s is not a directory", subDir)
-            }
-
-            err = storage.client.Mkdir(subDir)
-            if err != nil {
-                // The directory may have been created by other threads so check it again.
-                stat, _ := storage.client.Stat(subDir)
-                if stat == nil || !stat.IsDir() {
-                    return "", false, 0, fmt.Errorf("Failed to create the directory %s: %v", subDir, err)
-                }
-            }
-
-            dir = subDir
-            continue
-        }
-
-        // Teh chunk must be under this subdirectory but it doesn't exist.
-        return path.Join(dir, chunkID[2 * level:])[len(storage.storageDir) + 1:] + suffix, false, 0, nil
-
-    }
-
-    LOG_FATAL("CHUNK_FIND", "Chunk %s is still not found after having searched a maximum level of directories",
-              chunkID)
-    return "", false, 0, nil
-}
-
 // DownloadFile reads the file at 'filePath' into the chunk.
 func (storage *SFTPStorage) DownloadFile(threadIndex int, filePath string, chunk *Chunk) (err error) {
-    file, err := storage.client.Open(path.Join(storage.storageDir, filePath))
+	return storage.retry(func() error {
+		file, err := storage.getSFTPClient().Open(path.Join(storage.storageDir, filePath))
 
 		if err != nil {
 			return err
@@ -248,8 +275,8 @@ func (storage *SFTPStorage) DownloadFile(threadIndex int, filePath string, chunk
 		if _, err = RateLimitedCopy(chunk, file, storage.DownloadRateLimit/storage.numberOfThreads); err != nil {
 			return err
 		}
-
 		return nil
+	})
 }
 
 // UploadFile writes 'content' to the file at 'filePath'.
@@ -257,6 +284,21 @@ func (storage *SFTPStorage) UploadFile(threadIndex int, filePath string, content
 
 	fullPath := path.Join(storage.storageDir, filePath)
 
+	dirs := strings.Split(filePath, "/")
+	fullDir := path.Dir(fullPath)
+	return storage.retry(func() error {
+
+		if len(dirs) > 1 {
+			_, err := storage.getSFTPClient().Stat(fullDir)
+			if os.IsNotExist(err) {
+				for i := range dirs[1 : len(dirs)-1] {
+					subDir := path.Join(storage.storageDir, path.Join(dirs[0:i+2]...))
+					// We don't check the error; just keep going blindly
+					storage.getSFTPClient().Mkdir(subDir)
+				}
+			}
+		}
+
 		letters := "abcdefghijklmnopqrstuvwxyz"
 		suffix := make([]byte, 8)
 		for i := range suffix {
@@ -265,7 +307,7 @@ func (storage *SFTPStorage) UploadFile(threadIndex int, filePath string, content
 
 		temporaryFile := fullPath + "." + string(suffix) + ".tmp"
 
-    file, err := storage.client.OpenFile(temporaryFile, os.O_WRONLY | os.O_CREATE | os.O_TRUNC)
+		file, err := storage.getSFTPClient().OpenFile(temporaryFile, os.O_WRONLY|os.O_CREATE|os.O_TRUNC)
 		if err != nil {
 			return err
 		}
@@ -276,13 +318,16 @@ func (storage *SFTPStorage) UploadFile(threadIndex int, filePath string, content
 			file.Close()
 			return err
 		}
-    file.Close()
 
-    err = storage.client.Rename(temporaryFile, fullPath)
+		err = file.Close()
 		if err != nil {
+			return err
+		}
 
-        if _, err = storage.client.Stat(fullPath); err == nil {
-            storage.client.Remove(temporaryFile)
+		err = storage.getSFTPClient().Rename(temporaryFile, fullPath)
+		if err != nil {
+			if _, err = storage.getSFTPClient().Stat(fullPath); err == nil {
+				storage.getSFTPClient().Remove(temporaryFile)
 				return nil
 			} else {
 				return fmt.Errorf("Uploaded file but failed to store it at %s: %v", fullPath, err)
@@ -290,20 +335,28 @@ func (storage *SFTPStorage) UploadFile(threadIndex int, filePath string, content
 		}
 
 		return nil
+	})
 }
 
 // If a local snapshot cache is needed for the storage to avoid downloading/uploading chunks too often when
 // managing snapshots.
-func (storage *SFTPStorage) IsCacheNeeded () (bool) { return true }
+func (storage *SFTPStorage) IsCacheNeeded() bool { return true }
 
 // If the 'MoveFile' method is implemented.
-func (storage *SFTPStorage) IsMoveFileImplemented() (bool) { return true }
+func (storage *SFTPStorage) IsMoveFileImplemented() bool { return true }
 
 // If the storage can guarantee strong consistency.
-func (storage *SFTPStorage) IsStrongConsistent() (bool) { return true }
+func (storage *SFTPStorage) IsStrongConsistent() bool { return true }
 
 // If the storage supports fast listing of files names.
-func (storage *SFTPStorage) IsFastListing() (bool) { return false }
+func (storage *SFTPStorage) IsFastListing() bool {
+	for _, level := range storage.readLevels {
+		if level > 1 {
+			return false
+		}
+	}
+	return true
+}
 
 // Enable the test mode.
 func (storage *SFTPStorage) EnableTestMode() {}

src/duplicacy_shadowcopy.go

@@ -3,10 +3,11 @@
 // Commercial use requires per-user licenses available from https://duplicacy.com
 
 // +build !windows
+// +build !darwin
 
 package duplicacy
 
-func CreateShadowCopy(top string, shadowCopy bool) (shadowTop string) {
+func CreateShadowCopy(top string, shadowCopy bool, timeoutInSeconds int) (shadowTop string) {
 	return top
 }
 

src/duplicacy_shadowcopy_darwin.go

@@ -0,0 +1,186 @@
+//
+// Shadow copy module for Mac OSX using APFS snapshot
+//
+//
+// This module copyright 2018 Adam Marcus (https://github.com/amarcu5)
+// and may be distributed under the same terms as Duplicacy.
+
+package duplicacy
+
+import (
+	"context"
+	"errors"
+	"io/ioutil"
+	"os"
+	"os/exec"
+	"regexp"
+	"syscall"
+	"time"
+)
+
+var snapshotPath string
+var snapshotDate string
+
+// Converts char array to string
+func CharsToString(ca []int8) string {
+
+	len := len(ca)
+	ba := make([]byte, len)
+
+	for i, v := range ca {
+		ba[i] = byte(v)
+		if ba[i] == 0 {
+			len = i
+			break
+		}
+	}
+
+	return string(ba[:len])
+}
+
+// Get ID of device containing path
+func GetPathDeviceId(path string) (deviceId int32, err error) {
+
+	stat := syscall.Stat_t{}
+
+	err = syscall.Stat(path, &stat)
+	if err != nil {
+		return 0, err
+	}
+
+	return stat.Dev, nil
+}
+
+// Executes shell command with timeout and returns stdout
+func CommandWithTimeout(timeoutInSeconds int, name string, arg ...string) (output string, err error) {
+
+	ctx, cancel := context.WithTimeout(context.Background(), time.Duration(timeoutInSeconds)*time.Second)
+	defer cancel()
+
+	cmd := exec.CommandContext(ctx, name, arg...)
+	out, err := cmd.Output()
+
+	if ctx.Err() == context.DeadlineExceeded {
+		err = errors.New("Command '" + name + "' timed out")
+	}
+
+	output = string(out)
+	return output, err
+}
+
+func DeleteShadowCopy() {
+
+	if snapshotPath == "" {
+		return
+	}
+
+	err := exec.Command("/sbin/umount", "-f", snapshotPath).Run()
+	if err != nil {
+		LOG_WARN("VSS_DELETE", "Error while unmounting snapshot: %v", err)
+		return
+	}
+
+	err = exec.Command("tmutil", "deletelocalsnapshots", snapshotDate).Run()
+	if err != nil {
+		LOG_WARN("VSS_DELETE", "Error while deleting local snapshot: %v", err)
+		return
+	}
+
+	err = os.RemoveAll(snapshotPath)
+	if err != nil {
+		LOG_WARN("VSS_DELETE", "Error while deleting temporary mount directory: %v", err)
+		return
+	}
+
+	LOG_INFO("VSS_DELETE", "Shadow copy unmounted and deleted at %s", snapshotPath)
+
+	snapshotPath = ""
+}
+
+func CreateShadowCopy(top string, shadowCopy bool, timeoutInSeconds int) (shadowTop string) {
+
+	if !shadowCopy {
+		return top
+	}
+
+	// Check repository filesystem is APFS
+	stat := syscall.Statfs_t{}
+	err := syscall.Statfs(top, &stat)
+	if err != nil {
+		LOG_ERROR("VSS_INIT", "Unable to determine filesystem of repository path")
+		return top
+	}
+	if CharsToString(stat.Fstypename[:]) != "apfs" {
+		LOG_WARN("VSS_INIT", "VSS requires APFS filesystem")
+		return top
+	}
+
+	// Check path is local as tmutil snapshots will not support APFS formatted external drives
+	deviceIdLocal, err := GetPathDeviceId("/")
+	if err != nil {
+		LOG_ERROR("VSS_INIT", "Unable to get device ID of path: /")
+		return top
+	}
+	deviceIdRepository, err := GetPathDeviceId(top)
+	if err != nil {
+		LOG_ERROR("VSS_INIT", "Unable to get device ID of path: %s", top)
+		return top
+	}
+	if deviceIdLocal != deviceIdRepository {
+		LOG_WARN("VSS_PATH", "VSS not supported for non-local repository path: %s", top)
+		return top
+	}
+
+	if timeoutInSeconds <= 60 {
+		timeoutInSeconds = 60
+	}
+
+	// Create mount point
+	snapshotPath, err = ioutil.TempDir("/tmp/", "snp_")
+	if err != nil {
+		LOG_ERROR("VSS_CREATE", "Failed to create temporary mount directory")
+		return top
+	}
+
+	// Use tmutil to create snapshot
+	tmutilOutput, err := CommandWithTimeout(timeoutInSeconds, "tmutil", "snapshot")
+	if err != nil {
+		LOG_ERROR("VSS_CREATE", "Error while calling tmutil: %v", err)
+		return top
+	}
+
+	snapshotDateRegex := regexp.MustCompile(`:\s+([0-9\-]+)`)
+	matched := snapshotDateRegex.FindStringSubmatch(tmutilOutput)
+	if matched == nil {
+		LOG_ERROR("VSS_CREATE", "Snapshot creation failed: %s", tmutilOutput)
+		return top
+	}
+	snapshotDate = matched[1]
+
+	tmutilOutput, err = CommandWithTimeout(timeoutInSeconds, "tmutil", "listlocalsnapshots", ".")
+	if err != nil {
+		LOG_ERROR("VSS_CREATE", "Error while calling 'tmutil listlocalsnapshots': %v", err)
+		return top
+	}
+	snapshotName := "com.apple.TimeMachine." + snapshotDate
+ 
+	snapshotNameRegex := regexp.MustCompile(`(?m)^(.+` + snapshotDate + `.*)$`)
+	matched = snapshotNameRegex.FindStringSubmatch(tmutilOutput)
+	if len(matched) > 0 {
+		snapshotName = matched[0]
+	} else {
+		LOG_INFO("VSS_CREATE", "Can't find the snapshot name with 'tmutil listlocalsnapshots'; fallback to %s", snapshotName)
+	}
+ 
+	// Mount snapshot as readonly and hide from GUI i.e. Finder
+	_, err = CommandWithTimeout(timeoutInSeconds,
+		"/sbin/mount", "-t", "apfs", "-o", "nobrowse,-r,-s="+snapshotName, "/System/Volumes/Data", snapshotPath)
+	if err != nil {
+		LOG_ERROR("VSS_CREATE", "Error while mounting snapshot: %v", err)
+		return top
+	}
+
+	LOG_INFO("VSS_DONE", "Shadow copy created and mounted at %s", snapshotPath)
+
+	return snapshotPath + top
+}

src/duplicacy_shadowcopy_windows.go

@@ -5,11 +5,11 @@
 package duplicacy
 
 import (
-    "syscall"
-    "unsafe"
-    "time"
 	"os"
 	"runtime"
+	"syscall"
+	"time"
+	"unsafe"
 
 	ole "github.com/gilbertchen/go-ole"
 )
@@ -77,7 +77,6 @@ func getIVSSAsync(unknown *ole.IUnknown, iid *ole.GUID) (async *IVSSAsync) {
 	return
 }
 
-
 //665c1d5f-c218-414d-a05d-7fef5f9d5c86
 var IID_IVSS = &ole.GUID{0x665c1d5f, 0xc218, 0x414d, [8]byte{0xa0, 0x5d, 0x7f, 0xef, 0x5f, 0x9d, 0x5c, 0x86}}
 
@@ -238,7 +237,7 @@ type SnapshotProperties struct {
 	Status               int
 }
 
-func (vss *IVSS) GetSnapshotProperties(snapshotSetID ole.GUID, properties *SnapshotProperties) (int) {
+func (vss *IVSS) GetSnapshotProperties(snapshotSetID ole.GUID, properties *SnapshotProperties) int {
 	var ret uintptr
 	if runtime.GOARCH == "386" {
 		address := uint(uintptr(unsafe.Pointer(&snapshotSetID)))
@@ -292,8 +291,7 @@ func (vss *IVSS) DeleteSnapshots(snapshotID ole.GUID) (int, int, ole.GUID) {
 	return int(ret), int(deleted), deletedGUID
 }
 
-
-func uint16ArrayToString(p *uint16) (string) {
+func uint16ArrayToString(p *uint16) string {
 	if p == nil {
 		return ""
 	}
@@ -355,12 +353,15 @@ func DeleteShadowCopy() {
 	ole.CoUninitialize()
 }
 
-func CreateShadowCopy(top string, shadowCopy bool) (shadowTop string) {
+func CreateShadowCopy(top string, shadowCopy bool, timeoutInSeconds int) (shadowTop string) {
 
 	if !shadowCopy {
 		return top
 	}
 
+	if timeoutInSeconds <= 60 {
+		timeoutInSeconds = 60
+	}
 	ole.CoInitialize(0)
 	defer ole.CoUninitialize()
 
@@ -418,7 +419,7 @@ func CreateShadowCopy(top string, shadowCopy bool) (shadowTop string) {
 		return top
 	}
 
-    if !async.Wait(20) {
+	if !async.Wait(timeoutInSeconds) {
 		LOG_ERROR("VSS_GATHER", "Shadow copy creation failed: GatherWriterMetadata didn't finish properly")
 		return top
 	}
@@ -458,7 +459,7 @@ func CreateShadowCopy(top string, shadowCopy bool) (shadowTop string) {
 		return top
 	}
 
-    if !async.Wait(20) {
+	if !async.Wait(timeoutInSeconds) {
 		LOG_ERROR("VSS_PREPARE", "Shadow copy creation failed: PrepareForBackup didn't finish properly")
 		return top
 	}
@@ -475,15 +476,13 @@ func CreateShadowCopy(top string, shadowCopy bool) (shadowTop string) {
 		return top
 	}
 
-    if !async.Wait(60) {
+	if !async.Wait(timeoutInSeconds) {
 		LOG_ERROR("VSS_SNAPSHOT", "Shadow copy creation failed: DoSnapshotSet didn't finish properly")
 		return top
 	}
 	async.Release()
 
-
-    properties := SnapshotProperties {
-    }
+	properties := SnapshotProperties{}
 
 	ret = vssBackupComponent.GetSnapshotProperties(snapshotID, &properties)
 	if ret != 0 {
@@ -521,5 +520,3 @@ func CreateShadowCopy(top string, shadowCopy bool) (shadowTop string) {
 	return shadowLink + "\\" + top[2:]
 
 }
-
-

src/duplicacy_snapshot.go

@@ -5,19 +5,24 @@
 package duplicacy
 
 import (
-    "os"
-    "fmt"
-    "time"
-    "path"
-    "strings"
-    "strconv"
-    "io/ioutil"
-    "encoding/json"
 	"encoding/hex"
+	"encoding/json"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"strings"
+	"time"
+	"sort"
+
+    "github.com/vmihailenco/msgpack"
+
 )
 
 // Snapshot represents a backup of the repository.
 type Snapshot struct {
+	Version       int
 	ID            string // the snapshot id; must be different for different repositories
 	Revision      int    // the revision number
 	Options       string // options used to create this snapshot (some not included)
@@ -36,199 +41,266 @@ type Snapshot struct {
 	// A sequence of chunks whose aggregated content is the json representation of 'ChunkLengths'.
 	LengthSequence []string
 
-    Files          []*Entry    // list of files and subdirectories
-
 	ChunkHashes  []string // a sequence of chunks representing the file content
 	ChunkLengths []int    // the length of each chunk
 
 	Flag bool // used to mark certain snapshots for deletion or copy
 
-    discardAttributes bool
 }
 
 // CreateEmptySnapshot creates an empty snapshot.
 func CreateEmptySnapshot(id string) (snapshto *Snapshot) {
 	return &Snapshot{
+		Version:   1,
 		ID:        id,
 		Revision:  0,
 		StartTime: time.Now().Unix(),
 	}
 }
 
-// CreateSnapshotFromDirectory creates a snapshot from the local directory 'top'.  Only 'Files'
-// will be constructed, while 'ChunkHashes' and 'ChunkLengths' can only be populated after uploading.
-func CreateSnapshotFromDirectory(id string, top string) (snapshot *Snapshot, skippedDirectories []string,
-                                                         skippedFiles []string, err error) {
-
-    snapshot = &Snapshot {
-        ID : id,
-        Revision: 0,
-        StartTime: time.Now().Unix(),
+type DirectoryListing struct {
+	directory string
+	files *[]Entry
 }
 
+func (snapshot *Snapshot) ListLocalFiles(top string, nobackupFile string,
+								         filtersFile string, excludeByAttribute bool, listingChannel chan *Entry,
+								         skippedDirectories *[]string, skippedFiles *[]string) {
+
 	var patterns []string
 
-    patternFile, err := ioutil.ReadFile(path.Join(GetDuplicacyPreferencePath(), "filters"))
-    if err == nil {
-        for _, pattern := range strings.Split(string(patternFile), "\n") {
-            pattern = strings.TrimSpace(pattern)
-            if len(pattern) == 0 {
+	if filtersFile == "" {
+		filtersFile = joinPath(GetDuplicacyPreferencePath(), "filters")
+	}
+	patterns = ProcessFilters(filtersFile)
+
+	directories := make([]*Entry, 0, 256)
+	directories = append(directories, CreateEntry("", 0, 0, 0))
+
+	for len(directories) > 0 {
+
+		directory := directories[len(directories)-1]
+		directories = directories[:len(directories)-1]
+		subdirectories, skipped, err := ListEntries(top, directory.Path, patterns, nobackupFile, excludeByAttribute, listingChannel)
+		if err != nil {
+			if directory.Path == "" {
+				LOG_ERROR("LIST_FAILURE", "Failed to list the repository root: %v", err)
+				return
+			}
+			LOG_WARN("LIST_FAILURE", "Failed to list subdirectory %s: %v", directory.Path, err)
+			if skippedDirectories != nil {
+				*skippedDirectories = append(*skippedDirectories, directory.Path)
+			}
 			continue
 		}
 
-            if pattern[0] != '+' && pattern[0] != '-' {
-                pattern = "+" + pattern
+		directories = append(directories, subdirectories...)
+
+		if skippedFiles != nil {
+			*skippedFiles = append(*skippedFiles, skipped...)
 		}
 
-            if pattern == "+" || pattern == "-" {
-                continue
+	}
+	close(listingChannel)
 }
 
-            patterns = append(patterns, pattern)
+func (snapshot *Snapshot)ListRemoteFiles(config *Config, chunkOperator *ChunkOperator, entryOut func(*Entry) bool) {
+
+	var chunks []string
+	for _, chunkHash := range snapshot.FileSequence {
+		chunks = append(chunks, chunkOperator.config.GetChunkIDFromHash(chunkHash))
 	}
 
+	var chunk *Chunk
+	reader := NewSequenceReader(snapshot.FileSequence, func(chunkHash string) []byte {
+		if chunk != nil {
+			config.PutChunk(chunk)
+		}
+		chunk = chunkOperator.Download(chunkHash, 0, true)
+		return chunk.GetBytes()
+	})
+
+	defer func() {
+		if chunk != nil {
+			config.PutChunk(chunk)
+		}
+	} ()
+
+	// Normally if Version is 0 then the snapshot is created by CLI v2 but unfortunately CLI 3.0.1 does not set the
+	// version bit correctly when copying old backups.  So we need to check the first byte -- if it is '[' then it is
+	// the old format.  The new format starts with a string encoded in msgpack and the first byte can't be '['.
+	if snapshot.Version == 0 || reader.GetFirstByte() == '['{
+		LOG_INFO("SNAPSHOT_VERSION", "snapshot %s at revision %d is encoded in an old version format", snapshot.ID, snapshot.Revision)
+		files := make([]*Entry, 0)
+		decoder := json.NewDecoder(reader)
+
+		// read open bracket
+		_, err := decoder.Token()
+		if err != nil {
+			LOG_ERROR("SNAPSHOT_PARSE", "Failed to open the snapshot %s at revision %d: not a list of entries",
+				snapshot.ID, snapshot.Revision)
+			return
+		}
+
+		for decoder.More() {
+			var entry Entry
+			err = decoder.Decode(&entry)
+			if err != nil {
+				LOG_ERROR("SNAPSHOT_PARSE", "Failed to load files specified in the snapshot %s at revision %d: %v",
+					snapshot.ID, snapshot.Revision, err)
+				return
+			}
+			files = append(files, &entry)
+		}
+
+		sort.Sort(ByName(files))
+
+		for _, file := range files {
+			if !entryOut(file) {
+				return
+			}
+		}
+	} else if snapshot.Version == 1 {
+		decoder := msgpack.NewDecoder(reader)
+
+		lastEndChunk := 0
+
+		// while the array contains values
+		for _, err := decoder.PeekCode(); err != io.EOF; _, err = decoder.PeekCode() {
+			if err != nil {
+				LOG_ERROR("SNAPSHOT_PARSE", "Failed to parse the snapshot %s at revision %d: %v",
+					snapshot.ID, snapshot.Revision, err)
+				return
+			}
+			var entry Entry
+			err = decoder.Decode(&entry)
+			if err != nil {
+				LOG_ERROR("SNAPSHOT_PARSE", "Failed to load the snapshot %s at revision %d: %v",
+					snapshot.ID, snapshot.Revision, err)
+				return
+			}
+
+			if entry.IsFile() {
+				entry.StartChunk += lastEndChunk
+				entry.EndChunk += entry.StartChunk
+				lastEndChunk = entry.EndChunk
+			}
+
+			err = entry.check(snapshot.ChunkLengths)
+			if err != nil {
+				LOG_ERROR("SNAPSHOT_ENTRY", "Failed to load the snapshot %s at revision %d: %v",
+					snapshot.ID, snapshot.Revision, err)
+				return
+			}
+
+			if !entryOut(&entry) {
+				return
+			}
+		}
+
+	} else {
+		LOG_ERROR("SNAPSHOT_VERSION", "snapshot %s at revision %d is encoded in unsupported version %d format",
+				  snapshot.ID, snapshot.Revision, snapshot.Version)
+		return
+	}
+
+}
+
+func AppendPattern(patterns []string, new_pattern string) (new_patterns []string) {
+	for _, pattern := range patterns {
+		if pattern == new_pattern {
+			LOG_INFO("SNAPSHOT_FILTER", "Ignoring duplicate pattern: %s ...", new_pattern)
+			return patterns
+		}
+	}
+	new_patterns = append(patterns, new_pattern)
+	return new_patterns
+}
+func ProcessFilters(filtersFile string) (patterns []string) {
+	patterns = ProcessFilterFile(filtersFile, make([]string, 0))
+
+	LOG_DEBUG("REGEX_DEBUG", "There are %d compiled regular expressions stored", len(RegexMap))
+
 	LOG_INFO("SNAPSHOT_FILTER", "Loaded %d include/exclude pattern(s)", len(patterns))
 
 	if IsTracing() {
 		for _, pattern := range patterns {
 			LOG_TRACE("SNAPSHOT_PATTERN", "Pattern: %s", pattern)
 		}
-        }
 
 	}
 
-    directories := make([]*Entry, 0, 256)
-    directories = append(directories, CreateEntry("", 0, 0, 0))
-
-    snapshot.Files = make([]*Entry, 0, 256)
-
-    attributeThreshold := 1024 * 1024
-    if attributeThresholdValue, found := os.LookupEnv("DUPLICACY_ATTRIBUTE_THRESHOLD"); found && attributeThresholdValue != "" {
-        attributeThreshold, _ = strconv.Atoi(attributeThresholdValue)
+	return patterns
 }
 
-    for len(directories) > 0 {
+func ProcessFilterFile(patternFile string, includedFiles []string) (patterns []string) {
+	for _, file := range includedFiles {
+		if file == patternFile {
+			// cycle in include mechanism discovered.
+			LOG_ERROR("SNAPSHOT_FILTER", "The filter file %s has already been included", patternFile)
+			return patterns
+		}
+	}
+	includedFiles = append(includedFiles, patternFile)
+	LOG_INFO("SNAPSHOT_FILTER", "Parsing filter file %s", patternFile)
+	patternFileContent, err := ioutil.ReadFile(patternFile)
+	if err == nil {
+		patternFileLines := strings.Split(string(patternFileContent), "\n")
+		patterns = ProcessFilterLines(patternFileLines, includedFiles)
+	}
+	return patterns
+}
 
-        directory := directories[len(directories) - 1]
-        directories = directories[:len(directories) - 1]
-        snapshot.Files = append(snapshot.Files, directory)
-        subdirectories, skipped, err := ListEntries(top, directory.Path, &snapshot.Files, patterns, snapshot.discardAttributes)
-        if err != nil {
-            LOG_WARN("LIST_FAILURE", "Failed to list subdirectory: %v", err)
-            skippedDirectories = append(skippedDirectories, directory.Path)
+func ProcessFilterLines(patternFileLines []string, includedFiles []string) (patterns []string) {
+	for _, pattern := range patternFileLines {
+		pattern = strings.TrimSpace(pattern)
+		if len(pattern) == 0 {
 			continue
 		}
 
-        directories = append(directories, subdirectories...)
-        skippedFiles = append(skippedFiles, skipped...)
-
-        if !snapshot.discardAttributes && len(snapshot.Files) > attributeThreshold {
-            LOG_INFO("LIST_ATTRIBUTES", "Discarding file attributes")
-            snapshot.discardAttributes = true
-            for _, file := range snapshot.Files {
-                file.Attributes = nil
+		if strings.HasPrefix(pattern, "@") {
+			patternIncludeFile := strings.TrimSpace(pattern[1:])
+			if patternIncludeFile == "" {
+				continue
 			}
-        }
-    }
-
-    // Remove the root entry
-    snapshot.Files = snapshot.Files[1:]
-
-    return snapshot, skippedDirectories, skippedFiles, nil
-}
-
-// This is the struct used to save/load incomplete snapshots
-type IncompleteSnapshot struct {
-    Files [] *Entry
-    ChunkHashes []string
-    ChunkLengths [] int
-}
-
-// LoadIncompleteSnapshot loads the incomplete snapshot if it exists
-func LoadIncompleteSnapshot() (snapshot *Snapshot) {
-    snapshotFile := path.Join(GetDuplicacyPreferencePath(), "incomplete")
-    description, err := ioutil.ReadFile(snapshotFile)    
-    if err != nil {
-        LOG_DEBUG("INCOMPLETE_LOCATE", "Failed to locate incomplete snapshot: %v", err)
-        return nil
-    }
-
-    var incompleteSnapshot IncompleteSnapshot
-
-    err = json.Unmarshal(description, &incompleteSnapshot)
-    if err != nil {
-        LOG_DEBUG("INCOMPLETE_PARSE", "Failed to parse incomplete snapshot: %v", err)
-        return nil
-    }
-
-    var chunkHashes []string
-    for _, chunkHash := range incompleteSnapshot.ChunkHashes {
-        hash, err := hex.DecodeString(chunkHash)
-        if err != nil {
-            LOG_DEBUG("INCOMPLETE_DECODE", "Failed to decode incomplete snapshot: %v", err)
-            return nil
-        }
-        chunkHashes = append(chunkHashes, string(hash))
-    }
-
-    snapshot = &Snapshot {
-        Files: incompleteSnapshot.Files,
-        ChunkHashes: chunkHashes,
-        ChunkLengths: incompleteSnapshot.ChunkLengths,
-    }      
-    LOG_INFO("INCOMPLETE_LOAD", "Incomplete snpashot loaded from %s", snapshotFile)
-    return snapshot
-}
-
-// SaveIncompleteSnapshot saves the incomplete snapshot under the preference directory
-func SaveIncompleteSnapshot(snapshot *Snapshot) {
-    var files []*Entry
-    for _, file := range snapshot.Files {
-        // All unprocessed files will have a size of -1
-        if file.Size >= 0 {
-            file.Attributes = nil
-            files = append(files, file)
+			if ! filepath.IsAbs(patternIncludeFile) {
+				basePath := ""
+				if len(includedFiles) == 0 {
+					basePath, _ = os.Getwd()
 				} else {
-            break
+					basePath = filepath.Dir(includedFiles[len(includedFiles)-1])
 				}
+				patternIncludeFile = joinPath(basePath, patternIncludeFile)
 			}
-    var chunkHashes []string
-    for _, chunkHash := range snapshot.ChunkHashes {
-        chunkHashes = append(chunkHashes, hex.EncodeToString([]byte(chunkHash)))
+			for _, pattern := range ProcessFilterFile(patternIncludeFile, includedFiles) {
+				patterns = AppendPattern(patterns, pattern)
+			}
+			continue
 		}
 
-    incompleteSnapshot := IncompleteSnapshot {
-        Files: files,
-        ChunkHashes: chunkHashes,
-        ChunkLengths: snapshot.ChunkLengths,
+		if pattern[0] == '#' {
+			continue
 		}
 
-    description, err := json.MarshalIndent(incompleteSnapshot, "", "  ")
-    if err != nil {
-        LOG_WARN("INCOMPLETE_ENCODE", "Failed to encode the incomplete snapshot: %v", err)
-        return
+		if IsUnspecifiedFilter(pattern) {
+			pattern = "+" + pattern
 		}
 
-    snapshotFile := path.Join(GetDuplicacyPreferencePath(), "incomplete")    
-    err = ioutil.WriteFile(snapshotFile, description, 0644)
-    if err != nil {
-        LOG_WARN("INCOMPLETE_WRITE", "Failed to save the incomplete snapshot: %v", err)        
-        return
+		if IsEmptyFilter(pattern) {
+			continue
 		}
 
-    LOG_INFO("INCOMPLETE_SAVE", "Incomplete snapshot saved to %s", snapshotFile)
+		if strings.HasPrefix(pattern, "i:") || strings.HasPrefix(pattern, "e:") {
+			valid, err := IsValidRegex(pattern[2:])
+			if !valid || err != nil {
+				LOG_ERROR("SNAPSHOT_FILTER", "Invalid regular expression encountered for filter: \"%s\", error: %v", pattern, err)
+			}
 		}
 
-func RemoveIncompleteSnapshot() {
-    snapshotFile := path.Join(GetDuplicacyPreferencePath(), "incomplete")    
-    if stat, err := os.Stat(snapshotFile); err == nil && !stat.IsDir() {
-        err = os.Remove(snapshotFile)
-        if err != nil {
-            LOG_INFO("INCOMPLETE_SAVE", "Failed to remove ncomplete snapshot: %v", err)
-        } else {
-            LOG_INFO("INCOMPLETE_SAVE", "Removed incomplete snapshot %s", snapshotFile)    
-        }
+		patterns = AppendPattern(patterns, pattern)
 	}
+
+	return patterns
 }
 
 // CreateSnapshotFromDescription creates a snapshot from json decription.
@@ -243,6 +315,14 @@ func CreateSnapshotFromDescription(description []byte) (snapshot *Snapshot, err
 
 	snapshot = &Snapshot{}
 
+	if value, ok := root["version"]; !ok {
+		snapshot.Version = 0
+	} else if version, ok := value.(float64); !ok {
+		return nil, fmt.Errorf("Invalid version is specified in the snapshot")
+	} else {
+		snapshot.Version = int(version)
+	}
+
 	if value, ok := root["id"]; !ok {
 		return nil, fmt.Errorf("No id is specified in the snapshot")
 	} else if snapshot.ID, ok = value.(string); !ok {
@@ -344,6 +424,11 @@ func (snapshot *Snapshot) LoadChunks(description []byte) (err error) {
 	return err
 }
 
+// ClearChunks removes loaded chunks from memory
+func (snapshot *Snapshot) ClearChunks() {
+	snapshot.ChunkHashes = nil
+}
+
 // LoadLengths construct 'ChunkLengths' from the json description.
 func (snapshot *Snapshot) LoadLengths(description []byte) (err error) {
 	return json.Unmarshal(description, &snapshot.ChunkLengths)
@@ -354,6 +439,7 @@ func (snapshot *Snapshot) MarshalJSON() ([] byte, error) {
 
 	object := make(map[string]interface{})
 
+	object["version"] = snapshot.Version
 	object["id"] = snapshot.ID
 	object["revision"] = snapshot.Revision
 	object["options"] = snapshot.Options
@@ -375,9 +461,7 @@ func (snapshot *Snapshot) MarshalJSON() ([] byte, error) {
 // MarshalSequence creates a json represetion for the specified chunk sequence.
 func (snapshot *Snapshot) MarshalSequence(sequenceType string) ([]byte, error) {
 
-    if sequenceType == "files" {
-        return json.Marshal(snapshot.Files)
-    } else if sequenceType == "chunks" {
+	if sequenceType == "chunks" {
 		return json.Marshal(encodeSequence(snapshot.ChunkHashes))
 	} else {
 		return json.Marshal(snapshot.ChunkLengths)
@@ -396,7 +480,7 @@ func (snapshot *Snapshot) SetSequence(sequenceType string, sequence [] string) {
 }
 
 // encodeSequence turns a sequence of binary hashes into a sequence of hex hashes.
-func encodeSequence(sequence[] string) ([] string) {
+func encodeSequence(sequence []string) []string {
 
 	sequenceInHex := make([]string, len(sequence))
 
@@ -407,4 +491,3 @@ func encodeSequence(sequence[] string) ([] string) {
 	return sequenceInHex
 }
 
-

src/duplicacy_snapshotmanager_test.go

@@ -5,15 +5,16 @@
 package duplicacy
 
 import (
-    "testing"
-    "os"
+	"crypto/rand"
+	"encoding/hex"
+	"encoding/json"
 	"fmt"
-    "time"
+	"io/ioutil"
+	"os"
 	"path"
 	"strings"
-    "crypto/rand"
-    "encoding/json"
-    "encoding/hex"
+	"testing"
+	"time"
 )
 
 func createDummySnapshot(snapshotID string, revision int, endTime int64) *Snapshot {
@@ -95,36 +96,38 @@ func createTestSnapshotManager(testDir string) *SnapshotManager {
 	os.RemoveAll(testDir)
 	os.MkdirAll(testDir, 0700)
 
-    storage, _ := CreateFileStorage(testDir, 1)
+	storage, _ := CreateFileStorage(testDir, false, 1)
 	storage.CreateDirectory(0, "chunks")
 	storage.CreateDirectory(0, "snapshots")
 	config := CreateConfig()
 	snapshotManager := CreateSnapshotManager(config, storage)
 
 	cacheDir := path.Join(testDir, "cache")
-    snapshotCache, _ := CreateFileStorage(cacheDir, 1)
+	snapshotCache, _ := CreateFileStorage(cacheDir, false, 1)
 	snapshotCache.CreateDirectory(0, "chunks")
 	snapshotCache.CreateDirectory(0, "snapshots")
 
 	snapshotManager.snapshotCache = snapshotCache
+
+	SetDuplicacyPreferencePath(testDir + "/.duplicacy")
+
 	return snapshotManager
 }
 
 func uploadTestChunk(manager *SnapshotManager, content []byte) string {
 
-    completionFunc := func(chunk *Chunk, chunkIndex int, skipped bool, chunkSize int, uploadSize int) {
+	chunkOperator := CreateChunkOperator(manager.config, manager.storage, nil, false, false, *testThreads, false)
+	chunkOperator.UploadCompletionFunc = func(chunk *Chunk, chunkIndex int, skipped bool, chunkSize int, uploadSize int) {
 		LOG_INFO("UPLOAD_CHUNK", "Chunk %s size %d uploaded", chunk.GetID(), chunkSize)
 	}
 
-    chunkUploader := CreateChunkUploader(manager.config, manager.storage, nil, testThreads, nil)
-    chunkUploader.completionFunc = completionFunc
-    chunkUploader.Start()
-
 	chunk := CreateChunk(manager.config, true)
 	chunk.Reset(true)
 	chunk.Write(content)
-    chunkUploader.StartChunk(chunk, 0)
-    chunkUploader.Stop()
+
+	chunkOperator.Upload(chunk, 0, false)
+	chunkOperator.WaitForCompletion()
+	chunkOperator.Stop()
 
 	return chunk.GetHash()
 }
@@ -140,7 +143,16 @@ func uploadRandomChunk(manager *SnapshotManager, chunkSize int) string {
 	return uploadTestChunk(manager, content)
 }
 
-func createTestSnapshot(manager *SnapshotManager, snapshotID string, revision int, startTime int64, endTime int64, chunkHashes []string) {
+func uploadRandomChunks(manager *SnapshotManager, chunkSize int, numberOfChunks int) []string {
+	chunkList := make([]string, 0)
+	for i := 0; i < numberOfChunks; i++ {
+		chunkHash := uploadRandomChunk(manager, chunkSize)
+		chunkList = append(chunkList, chunkHash)
+	}
+	return chunkList
+}
+
+func createTestSnapshot(manager *SnapshotManager, snapshotID string, revision int, startTime int64, endTime int64, chunkHashes []string, tag string) {
 
 	snapshot := &Snapshot{
 		ID:          snapshotID,
@@ -148,6 +160,7 @@ func createTestSnapshot(manager *SnapshotManager, snapshotID string, revision in
 		StartTime:   startTime,
 		EndTime:     endTime,
 		ChunkHashes: chunkHashes,
+		Tag:         tag,
 	}
 
 	var chunkHashesInHex []string
@@ -166,6 +179,12 @@ func createTestSnapshot(manager *SnapshotManager, snapshotID string, revision in
 
 func checkTestSnapshots(manager *SnapshotManager, expectedSnapshots int, expectedFossils int) {
 
+	manager.CreateChunkOperator(false, false, 1, false)
+	defer func() {
+		manager.chunkOperator.Stop()
+		manager.chunkOperator = nil
+	}()
+
 	var snapshotIDs []string
 	var err error
 
@@ -181,7 +200,7 @@ func checkTestSnapshots(manager *SnapshotManager, expectedSnapshots int, expecte
 
 	snapshotIDs, err = manager.ListSnapshotIDs()
 	if err != nil {
-        LOG_ERROR("SNAPSHOT_LIST", "Failed to list all snpashots: %v", err)
+		LOG_ERROR("SNAPSHOT_LIST", "Failed to list all snapshots: %v", err)
 		return
 	}
 
@@ -199,7 +218,7 @@ func checkTestSnapshots(manager *SnapshotManager, expectedSnapshots int, expecte
 			snapshot := manager.DownloadSnapshot(snapshotID, revision)
 			numberOfSnapshots++
 
-            for _, chunk := range manager.GetSnapshotChunks(snapshot) {
+			for _, chunk := range manager.GetSnapshotChunks(snapshot, false) {
 				chunks[chunk] = true
 			}
 		}
@@ -222,7 +241,7 @@ func checkTestSnapshots(manager *SnapshotManager, expectedSnapshots int, expecte
 	}
 }
 
-func TestSingleRepositoryPrune(t *testing.T) {
+func TestPruneSingleRepository(t *testing.T) {
 
 	setTestingT(t)
 
@@ -238,34 +257,35 @@ func TestSingleRepositoryPrune(t *testing.T) {
 
 	now := time.Now().Unix()
 	day := int64(24 * 3600)
-    t.Logf("Creating 1 snapshot")
-    createTestSnapshot(snapshotManager, "repository1", 1, now - 3 * day - 3600, now - 3 * day - 60, []string { chunkHash1, chunkHash2 })
-    checkTestSnapshots(snapshotManager, 1, 2)
+	t.Logf("Creating 2 snapshots")
+	createTestSnapshot(snapshotManager, "repository1", 1, now-4*day-3600, now-3*day-60, []string{chunkHash1, chunkHash2}, "tag")
+	createTestSnapshot(snapshotManager, "repository1", 2, now-4*day-3600, now-3*day-60, []string{chunkHash1, chunkHash2}, "tag")
+	checkTestSnapshots(snapshotManager, 2, 2)
 
 	t.Logf("Creating 2 snapshots")
-    createTestSnapshot(snapshotManager, "repository1", 2, now - 2 * day - 3600, now - 2 * day - 60, []string { chunkHash2, chunkHash3 })
-    createTestSnapshot(snapshotManager, "repository1", 3, now - 1 * day - 3600, now - 1 * day - 60, []string { chunkHash3, chunkHash4 })
-    checkTestSnapshots(snapshotManager, 3, 0)
+	createTestSnapshot(snapshotManager, "repository1", 3, now-2*day-3600, now-2*day-60, []string{chunkHash2, chunkHash3}, "tag")
+	createTestSnapshot(snapshotManager, "repository1", 4, now-1*day-3600, now-1*day-60, []string{chunkHash3, chunkHash4}, "tag")
+	checkTestSnapshots(snapshotManager, 4, 0)
 
-    t.Logf("Removing snapshot repository1 revision 1 with --exclusive")
-    snapshotManager.PruneSnapshots("repository1", "repository1", []int{1}, []string{}, []string{}, false, true, []string{}, false, false, false)
+	t.Logf("Removing snapshot repository1 revisions 1 and 2 with --exclusive")
+	snapshotManager.PruneSnapshots("repository1", "repository1", []int{1, 2}, []string{}, []string{}, false, true, []string{}, false, false, false, 1)
 	checkTestSnapshots(snapshotManager, 2, 0)
 
-    t.Logf("Removing snapshot repository1 revision 2 without --exclusive")
-    snapshotManager.PruneSnapshots("repository1", "repository1", []int{2}, []string{}, []string{}, false, false, []string{}, false, false, false)
+	t.Logf("Removing snapshot repository1 revision 3 without --exclusive")
+	snapshotManager.PruneSnapshots("repository1", "repository1", []int{3}, []string{}, []string{}, false, false, []string{}, false, false, false, 1)
 	checkTestSnapshots(snapshotManager, 1, 2)
 
 	t.Logf("Creating 1 snapshot")
 	chunkHash5 := uploadRandomChunk(snapshotManager, chunkSize)
-    createTestSnapshot(snapshotManager, "repository1", 4, now + 1 * day - 3600 , now + 1 * day, []string { chunkHash4, chunkHash5 })
+	createTestSnapshot(snapshotManager, "repository1", 5, now+1*day-3600, now+1*day, []string{chunkHash4, chunkHash5}, "tag")
 	checkTestSnapshots(snapshotManager, 2, 2)
 
 	t.Logf("Prune without removing any snapshots -- fossils will be deleted")
-    snapshotManager.PruneSnapshots("repository1", "repository1", []int{}, []string{}, []string{}, false, false, []string{}, false, false, false)
+	snapshotManager.PruneSnapshots("repository1", "repository1", []int{}, []string{}, []string{}, false, false, []string{}, false, false, false, 1)
 	checkTestSnapshots(snapshotManager, 2, 0)
 }
 
-func TestSingleHostPrune(t *testing.T) {
+func TestPruneSingleHost(t *testing.T) {
 
 	setTestingT(t)
 
@@ -282,31 +302,31 @@ func TestSingleHostPrune(t *testing.T) {
 	now := time.Now().Unix()
 	day := int64(24 * 3600)
 	t.Logf("Creating 3 snapshots")
-    createTestSnapshot(snapshotManager, "vm1@host1", 1, now - 3 * day - 3600, now - 3 * day - 60, []string { chunkHash1, chunkHash2 })
-    createTestSnapshot(snapshotManager, "vm1@host1", 2, now - 2 * day - 3600, now - 2 * day - 60, []string { chunkHash2, chunkHash3 })
-    createTestSnapshot(snapshotManager, "vm2@host1", 1, now - 3 * day - 3600, now - 3 * day - 60, []string { chunkHash3, chunkHash4 })
+	createTestSnapshot(snapshotManager, "vm1@host1", 1, now-3*day-3600, now-3*day-60, []string{chunkHash1, chunkHash2}, "tag")
+	createTestSnapshot(snapshotManager, "vm1@host1", 2, now-2*day-3600, now-2*day-60, []string{chunkHash2, chunkHash3}, "tag")
+	createTestSnapshot(snapshotManager, "vm2@host1", 1, now-3*day-3600, now-3*day-60, []string{chunkHash3, chunkHash4}, "tag")
 	checkTestSnapshots(snapshotManager, 3, 0)
 
 	t.Logf("Removing snapshot vm1@host1 revision 1 without --exclusive")
-    snapshotManager.PruneSnapshots("vm1@host1", "vm1@host1", []int{1}, []string{}, []string{}, false, false, []string{}, false, false, false)
+	snapshotManager.PruneSnapshots("vm1@host1", "vm1@host1", []int{1}, []string{}, []string{}, false, false, []string{}, false, false, false, 1)
 	checkTestSnapshots(snapshotManager, 2, 2)
 
 	t.Logf("Prune without removing any snapshots -- no fossils will be deleted")
-    snapshotManager.PruneSnapshots("vm1@host1", "vm1@host1", []int{}, []string{}, []string{}, false, false, []string{}, false, false, false)
+	snapshotManager.PruneSnapshots("vm1@host1", "vm1@host1", []int{}, []string{}, []string{}, false, false, []string{}, false, false, false, 1)
 	checkTestSnapshots(snapshotManager, 2, 2)
 
 	t.Logf("Creating 1 snapshot")
 	chunkHash5 := uploadRandomChunk(snapshotManager, chunkSize)
-    createTestSnapshot(snapshotManager, "vm2@host1", 2, now + 1 * day - 3600 , now + 1 * day, []string { chunkHash4, chunkHash5 })
+	createTestSnapshot(snapshotManager, "vm2@host1", 2, now+1*day-3600, now+1*day, []string{chunkHash4, chunkHash5}, "tag")
 	checkTestSnapshots(snapshotManager, 3, 2)
 
 	t.Logf("Prune without removing any snapshots -- fossils will be deleted")
-    snapshotManager.PruneSnapshots("vm1@host1", "vm1@host1", []int{}, []string{}, []string{}, false, false, []string{}, false, false, false)
+	snapshotManager.PruneSnapshots("vm1@host1", "vm1@host1", []int{}, []string{}, []string{}, false, false, []string{}, false, false, false, 1)
 	checkTestSnapshots(snapshotManager, 3, 0)
 
 }
 
-func TestMultipleHostPrune(t *testing.T) {
+func TestPruneMultipleHost(t *testing.T) {
 
 	setTestingT(t)
 
@@ -323,35 +343,35 @@ func TestMultipleHostPrune(t *testing.T) {
 	now := time.Now().Unix()
 	day := int64(24 * 3600)
 	t.Logf("Creating 3 snapshot")
-    createTestSnapshot(snapshotManager, "vm1@host1", 1, now - 3 * day - 3600, now - 3 * day - 60, []string { chunkHash1, chunkHash2 })
-    createTestSnapshot(snapshotManager, "vm1@host1", 2, now - 2 * day - 3600, now - 2 * day - 60, []string { chunkHash2, chunkHash3 })
-    createTestSnapshot(snapshotManager, "vm2@host2", 1, now - 3 * day - 3600, now - 3 * day - 60, []string { chunkHash3, chunkHash4 })
+	createTestSnapshot(snapshotManager, "vm1@host1", 1, now-3*day-3600, now-3*day-60, []string{chunkHash1, chunkHash2}, "tag")
+	createTestSnapshot(snapshotManager, "vm1@host1", 2, now-2*day-3600, now-2*day-60, []string{chunkHash2, chunkHash3}, "tag")
+	createTestSnapshot(snapshotManager, "vm2@host2", 1, now-3*day-3600, now-3*day-60, []string{chunkHash3, chunkHash4}, "tag")
 	checkTestSnapshots(snapshotManager, 3, 0)
 
 	t.Logf("Removing snapshot vm1@host1 revision 1 without --exclusive")
-    snapshotManager.PruneSnapshots("vm1@host1", "vm1@host1", []int{1}, []string{}, []string{}, false, false, []string{}, false, false, false)
+	snapshotManager.PruneSnapshots("vm1@host1", "vm1@host1", []int{1}, []string{}, []string{}, false, false, []string{}, false, false, false, 1)
 	checkTestSnapshots(snapshotManager, 2, 2)
 
 	t.Logf("Prune without removing any snapshots -- no fossils will be deleted")
-    snapshotManager.PruneSnapshots("vm1@host1", "vm1@host1", []int{}, []string{}, []string{}, false, false, []string{}, false, false, false)
+	snapshotManager.PruneSnapshots("vm1@host1", "vm1@host1", []int{}, []string{}, []string{}, false, false, []string{}, false, false, false, 1)
 	checkTestSnapshots(snapshotManager, 2, 2)
 
 	t.Logf("Creating 1 snapshot")
 	chunkHash5 := uploadRandomChunk(snapshotManager, chunkSize)
-    createTestSnapshot(snapshotManager, "vm2@host2", 2, now + 1 * day - 3600 , now + 1 * day, []string {chunkHash4, chunkHash5})
+	createTestSnapshot(snapshotManager, "vm2@host2", 2, now+1*day-3600, now+1*day, []string{chunkHash4, chunkHash5}, "tag")
 	checkTestSnapshots(snapshotManager, 3, 2)
 
 	t.Logf("Prune without removing any snapshots -- no fossils will be deleted")
-    snapshotManager.PruneSnapshots("vm1@host1", "vm1@host1", []int{}, []string{}, []string{}, false, false, []string{}, false, false, false)
+	snapshotManager.PruneSnapshots("vm1@host1", "vm1@host1", []int{}, []string{}, []string{}, false, false, []string{}, false, false, false, 1)
 	checkTestSnapshots(snapshotManager, 3, 2)
 
 	t.Logf("Creating 1 snapshot")
 	chunkHash6 := uploadRandomChunk(snapshotManager, chunkSize)
-    createTestSnapshot(snapshotManager, "vm1@host1", 3, now + 1 * day - 3600 , now + 1 * day, []string {chunkHash5, chunkHash6})
+	createTestSnapshot(snapshotManager, "vm1@host1", 3, now+1*day-3600, now+1*day, []string{chunkHash5, chunkHash6}, "tag")
 	checkTestSnapshots(snapshotManager, 4, 2)
 
 	t.Logf("Prune without removing any snapshots -- fossils will be deleted")
-    snapshotManager.PruneSnapshots("vm1@host1", "vm1@host1", []int{}, []string{}, []string{}, false, false, []string{}, false, false, false)
+	snapshotManager.PruneSnapshots("vm1@host1", "vm1@host1", []int{}, []string{}, []string{}, false, false, []string{}, false, false, false, 1)
 	checkTestSnapshots(snapshotManager, 4, 0)
 }
 
@@ -371,25 +391,25 @@ func TestPruneAndResurrect(t *testing.T) {
 	now := time.Now().Unix()
 	day := int64(24 * 3600)
 	t.Logf("Creating 2 snapshots")
-    createTestSnapshot(snapshotManager, "vm1@host1", 1, now - 3 * day - 3600, now - 3 * day - 60, []string { chunkHash1, chunkHash2})
-    createTestSnapshot(snapshotManager, "vm1@host1", 2, now - 2 * day - 3600, now - 2 * day - 60, []string { chunkHash2, chunkHash3})
+	createTestSnapshot(snapshotManager, "vm1@host1", 1, now-3*day-3600, now-3*day-60, []string{chunkHash1, chunkHash2}, "tag")
+	createTestSnapshot(snapshotManager, "vm1@host1", 2, now-2*day-3600, now-2*day-60, []string{chunkHash2, chunkHash3}, "tag")
 	checkTestSnapshots(snapshotManager, 2, 0)
 
 	t.Logf("Removing snapshot vm1@host1 revision 1 without --exclusive")
-    snapshotManager.PruneSnapshots("vm1@host1", "vm1@host1", []int{1}, []string{}, []string{}, false, false, []string{}, false, false, false)
+	snapshotManager.PruneSnapshots("vm1@host1", "vm1@host1", []int{1}, []string{}, []string{}, false, false, []string{}, false, false, false, 1)
 	checkTestSnapshots(snapshotManager, 1, 2)
 
 	t.Logf("Creating 1 snapshot")
 	chunkHash4 := uploadRandomChunk(snapshotManager, chunkSize)
-    createTestSnapshot(snapshotManager, "vm1@host1", 4, now + 1 * day - 3600 , now + 1 * day, []string { chunkHash4, chunkHash1})
+	createTestSnapshot(snapshotManager, "vm1@host1", 4, now+1*day-3600, now+1*day, []string{chunkHash4, chunkHash1}, "tag")
 	checkTestSnapshots(snapshotManager, 2, 2)
 
 	t.Logf("Prune without removing any snapshots -- one fossil will be resurrected")
-    snapshotManager.PruneSnapshots("vm1@host1", "vm1@host1", []int{}, []string{}, []string{}, false, false, []string{}, false, false, false)
+	snapshotManager.PruneSnapshots("vm1@host1", "vm1@host1", []int{}, []string{}, []string{}, false, false, []string{}, false, false, false, 1)
 	checkTestSnapshots(snapshotManager, 2, 0)
 }
 
-func TestInactiveHostPrune(t *testing.T) {
+func TestPruneWithInactiveHost(t *testing.T) {
 
 	setTestingT(t)
 
@@ -406,31 +426,31 @@ func TestInactiveHostPrune(t *testing.T) {
 	now := time.Now().Unix()
 	day := int64(24 * 3600)
 	t.Logf("Creating 3 snapshot")
-    createTestSnapshot(snapshotManager, "vm1@host1", 1, now - 3 * day - 3600, now - 3 * day - 60, []string { chunkHash1, chunkHash2} )
-    createTestSnapshot(snapshotManager, "vm1@host1", 2, now - 2 * day - 3600, now - 2 * day - 60, []string { chunkHash2, chunkHash3} )
+	createTestSnapshot(snapshotManager, "vm1@host1", 1, now-3*day-3600, now-3*day-60, []string{chunkHash1, chunkHash2}, "tag")
+	createTestSnapshot(snapshotManager, "vm1@host1", 2, now-2*day-3600, now-2*day-60, []string{chunkHash2, chunkHash3}, "tag")
 	// Host2 is inactive
-    createTestSnapshot(snapshotManager, "vm2@host2", 1, now - 7 * day - 3600, now - 7 * day - 60, []string { chunkHash3, chunkHash4} )
+	createTestSnapshot(snapshotManager, "vm2@host2", 1, now-7*day-3600, now-7*day-60, []string{chunkHash3, chunkHash4}, "tag")
 	checkTestSnapshots(snapshotManager, 3, 0)
 
 	t.Logf("Removing snapshot vm1@host1 revision 1")
-    snapshotManager.PruneSnapshots("vm1@host1", "vm1@host1", []int{1}, []string{}, []string{}, false, false, []string{}, false, false, false)
+	snapshotManager.PruneSnapshots("vm1@host1", "vm1@host1", []int{1}, []string{}, []string{}, false, false, []string{}, false, false, false, 1)
 	checkTestSnapshots(snapshotManager, 2, 2)
 
 	t.Logf("Prune without removing any snapshots -- no fossils will be deleted")
-    snapshotManager.PruneSnapshots("vm1@host1", "vm1@host1", []int{}, []string{}, []string{}, false, false, []string{}, false, false, false)
+	snapshotManager.PruneSnapshots("vm1@host1", "vm1@host1", []int{}, []string{}, []string{}, false, false, []string{}, false, false, false, 1)
 	checkTestSnapshots(snapshotManager, 2, 2)
 
 	t.Logf("Creating 1 snapshot")
 	chunkHash5 := uploadRandomChunk(snapshotManager, chunkSize)
-    createTestSnapshot(snapshotManager, "vm1@host1", 3, now + 1 * day - 3600 , now + 1 * day, []string { chunkHash4, chunkHash5} )
+	createTestSnapshot(snapshotManager, "vm1@host1", 3, now+1*day-3600, now+1*day, []string{chunkHash4, chunkHash5}, "tag")
 	checkTestSnapshots(snapshotManager, 3, 2)
 
 	t.Logf("Prune without removing any snapshots -- fossils will be deleted")
-    snapshotManager.PruneSnapshots("vm1@host1", "vm1@host1", []int{}, []string{}, []string{}, false, false, []string{}, false, false, false)
+	snapshotManager.PruneSnapshots("vm1@host1", "vm1@host1", []int{}, []string{}, []string{}, false, false, []string{}, false, false, false, 1)
 	checkTestSnapshots(snapshotManager, 3, 0)
 }
 
-func TestRetentionPolicy(t *testing.T) {
+func TestPruneWithRetentionPolicy(t *testing.T) {
 
 	setTestingT(t)
 
@@ -448,20 +468,225 @@ func TestRetentionPolicy(t *testing.T) {
 	day := int64(24 * 3600)
 	t.Logf("Creating 30 snapshots")
 	for i := 0; i < 30; i++ {
-        createTestSnapshot(snapshotManager, "vm1@host1", i + 1, now - int64(30 - i) * day - 3600, now - int64(30 - i) * day - 60, []string { chunkHashes[i] })
+		createTestSnapshot(snapshotManager, "vm1@host1", i+1, now-int64(30-i)*day-3600, now-int64(30-i)*day-60, []string{chunkHashes[i]}, "tag")
 	}
 
 	checkTestSnapshots(snapshotManager, 30, 0)
 
 	t.Logf("Removing snapshot vm1@host1 0:20 with --exclusive")
-    snapshotManager.PruneSnapshots("vm1@host1", "vm1@host1", []int{}, []string{}, []string{"0:20"}, false, true, []string{}, false, false, false)
+	snapshotManager.PruneSnapshots("vm1@host1", "vm1@host1", []int{}, []string{}, []string{"0:20"}, false, true, []string{}, false, false, false, 1)
 	checkTestSnapshots(snapshotManager, 19, 0)
 
 	t.Logf("Removing snapshot vm1@host1 -k 0:20 with --exclusive")
-    snapshotManager.PruneSnapshots("vm1@host1", "vm1@host1", []int{}, []string{}, []string{"0:20"}, false, true, []string{}, false, false, false)
+	snapshotManager.PruneSnapshots("vm1@host1", "vm1@host1", []int{}, []string{}, []string{"0:20"}, false, true, []string{}, false, false, false, 1)
 	checkTestSnapshots(snapshotManager, 19, 0)
 
 	t.Logf("Removing snapshot vm1@host1 -k 3:14 -k 2:7 with --exclusive")
-    snapshotManager.PruneSnapshots("vm1@host1", "vm1@host1", []int{}, []string{}, []string{"3:14", "2:7"}, false, true, []string{}, false, false, false)
+	snapshotManager.PruneSnapshots("vm1@host1", "vm1@host1", []int{}, []string{}, []string{"3:14", "2:7"}, false, true, []string{}, false, false, false, 1)
 	checkTestSnapshots(snapshotManager, 12, 0)
 }
+
+func TestPruneWithRetentionPolicyAndTag(t *testing.T) {
+
+	setTestingT(t)
+
+	testDir := path.Join(os.TempDir(), "duplicacy_test", "snapshot_test")
+
+	snapshotManager := createTestSnapshotManager(testDir)
+
+	chunkSize := 1024
+	var chunkHashes []string
+	for i := 0; i < 30; i++ {
+		chunkHashes = append(chunkHashes, uploadRandomChunk(snapshotManager, chunkSize))
+	}
+
+	now := time.Now().Unix()
+	day := int64(24 * 3600)
+	t.Logf("Creating 30 snapshots")
+	for i := 0; i < 30; i++ {
+		tag := "auto"
+		if i%3 == 0 {
+			tag = "manual"
+		}
+		createTestSnapshot(snapshotManager, "vm1@host1", i+1, now-int64(30-i)*day-3600, now-int64(30-i)*day-60, []string{chunkHashes[i]}, tag)
+	}
+
+	checkTestSnapshots(snapshotManager, 30, 0)
+
+	t.Logf("Removing snapshot vm1@host1 0:20 with --exclusive and --tag manual")
+	snapshotManager.PruneSnapshots("vm1@host1", "vm1@host1", []int{}, []string{"manual"}, []string{"0:7"}, false, true, []string{}, false, false, false, 1)
+	checkTestSnapshots(snapshotManager, 22, 0)
+}
+
+// Test that an unreferenced fossil shouldn't be removed as it may be the result of another prune job in-progress.
+func TestPruneWithFossils(t *testing.T) {
+	setTestingT(t)
+
+	testDir := path.Join(os.TempDir(), "duplicacy_test", "snapshot_test")
+
+	snapshotManager := createTestSnapshotManager(testDir)
+
+	chunkSize := 1024
+	chunkHash1 := uploadRandomChunk(snapshotManager, chunkSize)
+	chunkHash2 := uploadRandomChunk(snapshotManager, chunkSize)
+	chunkHash3 := uploadRandomChunk(snapshotManager, chunkSize)
+	// Create an unreferenced fossil
+	snapshotManager.storage.UploadFile(0, "chunks/113b6a2350dcfd836829c47304dd330fa6b58b93dd7ac696c6b7b913e6868662.fsl", []byte("this is a test fossil"))
+
+	now := time.Now().Unix()
+	day := int64(24 * 3600)
+	t.Logf("Creating 2 snapshots")
+	createTestSnapshot(snapshotManager, "vm1@host1", 1, now-3*day-3600, now-3*day-60, []string{chunkHash1, chunkHash2}, "tag")
+	createTestSnapshot(snapshotManager, "vm1@host1", 2, now-2*day-3600, now-2*day-60, []string{chunkHash2, chunkHash3}, "tag")
+	checkTestSnapshots(snapshotManager, 2, 1)
+
+	t.Logf("Prune without removing any snapshots but with --exhaustive")
+	// The unreferenced fossil shouldn't be removed
+	snapshotManager.PruneSnapshots("vm1@host1", "vm1@host1", []int{}, []string{}, []string{}, true, false, []string{}, false, false, false, 1)
+	checkTestSnapshots(snapshotManager, 2, 1)
+
+	t.Logf("Prune without removing any snapshots but with --exclusive")
+	// Now the unreferenced fossil should be removed
+	snapshotManager.PruneSnapshots("vm1@host1", "vm1@host1", []int{}, []string{}, []string{}, false, true, []string{}, false, false, false, 1)
+	checkTestSnapshots(snapshotManager, 2, 0)
+}
+
+func TestPruneMultipleThread(t *testing.T) {
+
+	setTestingT(t)
+
+	testDir := path.Join(os.TempDir(), "duplicacy_test", "snapshot_test")
+
+	snapshotManager := createTestSnapshotManager(testDir)
+
+	chunkSize := 1024
+	numberOfChunks := 256
+	numberOfThreads := 4
+
+	chunkList1 := uploadRandomChunks(snapshotManager, chunkSize, numberOfChunks)
+	chunkList2 := uploadRandomChunks(snapshotManager, chunkSize, numberOfChunks)
+
+	now := time.Now().Unix()
+	day := int64(24 * 3600)
+	t.Logf("Creating 2 snapshots")
+	createTestSnapshot(snapshotManager, "repository1", 1, now-4*day-3600, now-3*day-60, chunkList1, "tag")
+	createTestSnapshot(snapshotManager, "repository1", 2, now-3*day-3600, now-2*day-60, chunkList2, "tag")
+	checkTestSnapshots(snapshotManager, 2, 0)
+
+	t.Logf("Removing snapshot revisions 1 with --exclusive")
+	snapshotManager.PruneSnapshots("repository1", "repository1", []int{1}, []string{}, []string{}, false, true, []string{}, false, false, false, numberOfThreads)
+	checkTestSnapshots(snapshotManager, 1, 0)
+
+	t.Logf("Creating 1 more snapshot")
+	chunkList3 := uploadRandomChunks(snapshotManager, chunkSize, numberOfChunks)
+	createTestSnapshot(snapshotManager, "repository1", 3, now-2*day-3600, now-1*day-60, chunkList3, "tag")
+
+	t.Logf("Removing snapshot repository1 revision 2 without --exclusive")
+	snapshotManager.PruneSnapshots("repository1", "repository1", []int{2}, []string{}, []string{}, false, false, []string{}, false, false, false, numberOfThreads)
+
+	t.Logf("Prune without removing any snapshots but with --exclusive")
+	snapshotManager.PruneSnapshots("repository1", "repository1", []int{}, []string{}, []string{}, false, true, []string{}, false, false, false, numberOfThreads)
+	checkTestSnapshots(snapshotManager, 1, 0)
+}
+
+// A snapshot not seen by a fossil collection should always be consider a new snapshot in the fossil deletion step
+func TestPruneNewSnapshots(t *testing.T) {
+	setTestingT(t)
+
+	testDir := path.Join(os.TempDir(), "duplicacy_test", "snapshot_test")
+
+	snapshotManager := createTestSnapshotManager(testDir)
+
+	chunkSize := 1024
+	chunkHash1 := uploadRandomChunk(snapshotManager, chunkSize)
+	chunkHash2 := uploadRandomChunk(snapshotManager, chunkSize)
+	chunkHash3 := uploadRandomChunk(snapshotManager, chunkSize)
+	chunkHash4 := uploadRandomChunk(snapshotManager, chunkSize)
+
+	now := time.Now().Unix()
+	day := int64(24 * 3600)
+	t.Logf("Creating 3 snapshots")
+	createTestSnapshot(snapshotManager, "vm1@host1", 1, now-3*day-3600, now-3*day-60, []string{chunkHash1, chunkHash2}, "tag")
+	createTestSnapshot(snapshotManager, "vm1@host1", 2, now-2*day-3600, now-2*day-60, []string{chunkHash2, chunkHash3}, "tag")
+	createTestSnapshot(snapshotManager, "vm2@host1", 1, now-2*day-3600, now-2*day-60, []string{chunkHash3, chunkHash4}, "tag")
+	checkTestSnapshots(snapshotManager, 3, 0)
+
+	t.Logf("Prune snapshot 1")
+	// chunkHash1 should be marked as fossil
+	snapshotManager.PruneSnapshots("vm1@host1", "vm1@host1", []int{1}, []string{}, []string{}, false, false, []string{}, false, false, false, 1)
+	checkTestSnapshots(snapshotManager, 2, 2)
+
+	chunkHash5 := uploadRandomChunk(snapshotManager, chunkSize)
+	// Create another snapshot of vm1 that brings back chunkHash1
+	createTestSnapshot(snapshotManager, "vm1@host1", 3, now-0*day-3600, now-0*day-60, []string{chunkHash1, chunkHash3}, "tag")
+	// Create another snapshot of vm2 so the fossil collection will be processed by next prune
+	createTestSnapshot(snapshotManager, "vm2@host1", 2, now+3600, now+3600*2, []string{chunkHash4, chunkHash5}, "tag")
+
+	// Now chunkHash1 wil be resurrected
+	snapshotManager.PruneSnapshots("vm1@host1", "vm1@host1", []int{}, []string{}, []string{}, false, false, []string{}, false, false, false, 1)
+	checkTestSnapshots(snapshotManager, 4, 0)
+	snapshotManager.CheckSnapshots("vm1@host1", []int{2, 3}, "", false, false, false, false, false, false, false, 1, false)
+}
+
+// A fossil collection left by an aborted prune should be ignored if any supposedly deleted snapshot exists
+func TestPruneGhostSnapshots(t *testing.T) {
+	setTestingT(t)
+
+	EnableStackTrace()
+
+	testDir := path.Join(os.TempDir(), "duplicacy_test", "snapshot_test")
+
+	snapshotManager := createTestSnapshotManager(testDir)
+
+	chunkSize := 1024
+	chunkHash1 := uploadRandomChunk(snapshotManager, chunkSize)
+	chunkHash2 := uploadRandomChunk(snapshotManager, chunkSize)
+	chunkHash3 := uploadRandomChunk(snapshotManager, chunkSize)
+
+	now := time.Now().Unix()
+	day := int64(24 * 3600)
+	t.Logf("Creating 2 snapshots")
+	createTestSnapshot(snapshotManager, "vm1@host1", 1, now-3*day-3600, now-3*day-60, []string{chunkHash1, chunkHash2}, "tag")
+	createTestSnapshot(snapshotManager, "vm1@host1", 2, now-2*day-3600, now-2*day-60, []string{chunkHash2, chunkHash3}, "tag")
+	checkTestSnapshots(snapshotManager, 2, 0)
+
+	snapshot1, err := ioutil.ReadFile(path.Join(testDir, "snapshots", "vm1@host1", "1"))
+	if err != nil {
+		t.Errorf("Failed to read snapshot file: %v", err)
+	}
+
+	t.Logf("Prune snapshot 1")
+	// chunkHash1 should be marked as fossil
+	snapshotManager.PruneSnapshots("vm1@host1", "vm1@host1", []int{1}, []string{}, []string{}, false, false, []string{}, false, false, false, 1)
+	checkTestSnapshots(snapshotManager, 1, 2)
+
+	// Recover the snapshot file for revision 1; this is to simulate a scenario where prune may encounter a network error after
+	// leaving the fossil collection but before deleting any snapshots.
+	err = ioutil.WriteFile(path.Join(testDir, "snapshots", "vm1@host1", "1"), snapshot1, 0644)
+	if err != nil {
+		t.Errorf("Failed to write snapshot file: %v", err)
+	}
+
+	// Create another snapshot of vm1 so the fossil collection becomes eligible for processing.
+	chunkHash4 := uploadRandomChunk(snapshotManager, chunkSize)
+	createTestSnapshot(snapshotManager, "vm1@host1", 3, now-day-3600, now-day-60, []string{chunkHash3, chunkHash4}, "tag")
+
+	// Run the prune again but the fossil collection should be igored, since revision 1 still exists
+	snapshotManager.PruneSnapshots("vm1@host1", "vm1@host1", []int{}, []string{}, []string{}, false, false, []string{}, false, false, false, 1)
+	checkTestSnapshots(snapshotManager, 3, 2)
+	snapshotManager.CheckSnapshots("vm1@host1", []int{1, 2, 3}, "", false, false, false, false, true /*searchFossils*/, false, false, 1, false)
+
+	// Prune snapshot 1 again
+	snapshotManager.PruneSnapshots("vm1@host1", "vm1@host1", []int{1}, []string{}, []string{}, false, false, []string{}, false, false, false, 1)
+	checkTestSnapshots(snapshotManager, 2, 2)
+
+	// Create another snapshot
+	chunkHash5 := uploadRandomChunk(snapshotManager, chunkSize)
+	createTestSnapshot(snapshotManager, "vm1@host1", 4, now+3600, now+3600*2, []string{chunkHash5, chunkHash5}, "tag")
+	checkTestSnapshots(snapshotManager, 3, 2)
+
+	// Run the prune again and this time the fossil collection will be processed and the fossils removed
+	snapshotManager.PruneSnapshots("vm1@host1", "vm1@host1", []int{}, []string{}, []string{}, false, false, []string{}, false, false, false, 1)
+	checkTestSnapshots(snapshotManager, 3, 0)
+	snapshotManager.CheckSnapshots("vm1@host1", []int{2, 3, 4}, "", false, false, false, false, false, false, false, 1, false)
+}

src/duplicacy_storage.go

@@ -5,23 +5,26 @@
 package duplicacy
 
 import (
+	"encoding/json"
 	"fmt"
-    "regexp"
-    "strings"
-    "strconv"
-    "os"
-    "net"
-    "path"
 	"io/ioutil"
+	"net"
+	"os"
+	"path"
+	"regexp"
 	"runtime"
+	"strconv"
+	"strings"
 
 	"golang.org/x/crypto/ssh"
 	"golang.org/x/crypto/ssh/agent"
 )
 
 type Storage interface {
-    // ListFiles return the list of files and subdirectories under 'dir' (non-recursively)
-    ListFiles(threadIndex int, dir string) (files []string, size []int64, err error)
+	// ListFiles return the list of files and subdirectories under 'dir'.  A subdirectories returned must have a trailing '/', with
+	// a size of 0.  If 'dir' is 'snapshots', only subdirectories will be returned.  If 'dir' is 'snapshots/repository_id', then only
+	// files will be returned.  If 'dir' is 'chunks', the implementation can return the list either recusively or non-recusively.
+	ListFiles(threadIndex int, dir string) (files []string, sizes []int64, err error)
 
 	// DeleteFile deletes the file or directory at 'filePath'.
 	DeleteFile(threadIndex int, filePath string) (err error)
@@ -45,18 +48,21 @@ type Storage interface {
 	// UploadFile writes 'content' to the file at 'filePath'.
 	UploadFile(threadIndex int, filePath string, content []byte) (err error)
 
+	// SetNestingLevels sets up the chunk nesting structure.
+	SetNestingLevels(config *Config)
+
 	// If a local snapshot cache is needed for the storage to avoid downloading/uploading chunks too often when
 	// managing snapshots.
-    IsCacheNeeded() (bool)
+	IsCacheNeeded() bool
 
 	// If the 'MoveFile' method is implemented.
-    IsMoveFileImplemented() (bool)
+	IsMoveFileImplemented() bool
 
 	// If the storage can guarantee strong consistency.
-    IsStrongConsistent() (bool)
+	IsStrongConsistent() bool
 
 	// If the storage supports fast listing of files names.
-    IsFastListing() (bool)
+	IsFastListing() bool
 
 	// Enable the test mode.
 	EnableTestMode()
@@ -65,19 +71,102 @@ type Storage interface {
 	SetRateLimits(downloadRateLimit int, uploadRateLimit int)
 }
 
-type RateLimitedStorage struct {
-    DownloadRateLimit int
-    UploadRateLimit int
+// StorageBase is the base struct from which all storages are derived from
+type StorageBase struct {
+	DownloadRateLimit int // Maximum download rate (bytes/seconds)
+	UploadRateLimit   int // Maximum upload reate (bytes/seconds)
+
+	DerivedStorage Storage // Used as the pointer to the derived storage class
+
+	readLevels []int // At which nesting level to find the chunk with the given id
+	writeLevel int   // Store the uploaded chunk to this level
 }
 
-func (storage *RateLimitedStorage) SetRateLimits(downloadRateLimit int, uploadRateLimit int) {
+// SetRateLimits sets the maximum download and upload rates
+func (storage *StorageBase) SetRateLimits(downloadRateLimit int, uploadRateLimit int) {
 	storage.DownloadRateLimit = downloadRateLimit
 	storage.UploadRateLimit = uploadRateLimit
 }
 
+// SetDefaultNestingLevels sets the default read and write levels.  This is usually called by
+// derived storages to set the levels with old values so that storages initialized by earlier versions
+// will continue to work.
+func (storage *StorageBase) SetDefaultNestingLevels(readLevels []int, writeLevel int) {
+	storage.readLevels = readLevels
+	storage.writeLevel = writeLevel
+}
+
+// SetNestingLevels sets the new read and write levels (normally both at 1) if the 'config' file has
+// the 'fixed-nesting' key, or if a file named 'nesting' exists on the storage.
+func (storage *StorageBase) SetNestingLevels(config *Config) {
+
+	// 'FixedNesting' is true only for the 'config' file with the new format (2.0.10+)
+	if config.FixedNesting {
+
+		storage.readLevels = nil
+
+		// Check if the 'nesting' file exist
+		exist, _, _, err := storage.DerivedStorage.GetFileInfo(0, "nesting")
+		if err == nil && exist {
+			nestingFile := CreateChunk(CreateConfig(), true)
+			if storage.DerivedStorage.DownloadFile(0, "nesting", nestingFile) == nil {
+				var nesting struct {
+					ReadLevels []int `json:"read-levels"`
+					WriteLevel int   `json:"write-level"`
+				}
+				if json.Unmarshal(nestingFile.GetBytes(), &nesting) == nil {
+					storage.readLevels = nesting.ReadLevels
+					storage.writeLevel = nesting.WriteLevel
+				}
+			}
+		}
+
+		if len(storage.readLevels) == 0 {
+			storage.readLevels = []int{1}
+			storage.writeLevel = 1
+		}
+	}
+
+	LOG_DEBUG("STORAGE_NESTING", "Chunk read levels: %v, write level: %d", storage.readLevels, storage.writeLevel)
+	for _, level := range storage.readLevels {
+		if storage.writeLevel == level {
+			return
+		}
+	}
+	LOG_ERROR("STORAGE_NESTING", "The write level %d isn't in the read levels %v", storage.readLevels, storage.writeLevel)
+}
+
+// FindChunk finds the chunk with the specified id at the levels one by one as specified by 'readLevels'.
+func (storage *StorageBase) FindChunk(threadIndex int, chunkID string, isFossil bool) (filePath string, exist bool, size int64, err error) {
+	chunkPaths := make([]string, 0)
+	for _, level := range storage.readLevels {
+		chunkPath := "chunks/"
+		for i := 0; i < level; i++ {
+			chunkPath += chunkID[2*i:2*i+2] + "/"
+		}
+		chunkPath += chunkID[2*level:]
+		if isFossil {
+			chunkPath += ".fsl"
+		}
+		exist, _, size, err = storage.DerivedStorage.GetFileInfo(threadIndex, chunkPath)
+		if err == nil && exist {
+			return chunkPath, exist, size, err
+		}
+		chunkPaths = append(chunkPaths, chunkPath)
+	}
+	for i, level := range storage.readLevels {
+		if storage.writeLevel == level {
+			return chunkPaths[i], false, 0, nil
+		}
+	}
+	return "", false, 0, fmt.Errorf("Invalid chunk nesting setup")
+}
+
 func checkHostKey(hostname string, remote net.Addr, key ssh.PublicKey) error {
 
-    preferencePath := GetDuplicacyPreferencePath()
+	if preferencePath == "" {
+		return fmt.Errorf("Can't verify SSH host since the preference path is not set")
+	}
 	hostFile := path.Join(preferencePath, "known_hosts")
 	file, err := os.OpenFile(hostFile, os.O_RDWR|os.O_CREATE, 0600)
 	if err != nil {
@@ -127,6 +216,7 @@ func CreateStorage(preference Preference, resetPassword bool, threads int) (stor
 	storageURL := preference.StorageURL
 
 	isFileStorage := false
+	isCacheNeeded := false
 
 	if strings.HasPrefix(storageURL, "/") {
 		isFileStorage = true
@@ -140,11 +230,12 @@ func CreateStorage(preference Preference, resetPassword bool, threads int) (stor
 
 		if !isFileStorage && strings.HasPrefix(storageURL, `\\`) {
 			isFileStorage = true
+			isCacheNeeded = true
 		}
 	}
 
 	if isFileStorage {
-        fileStorage, err := CreateFileStorage(storageURL, threads)
+		fileStorage, err := CreateFileStorage(storageURL, isCacheNeeded, threads)
 		if err != nil {
 			LOG_ERROR("STORAGE_CREATE", "Failed to load the file storage at %s: %v", storageURL, err)
 			return nil
@@ -152,14 +243,33 @@ func CreateStorage(preference Preference, resetPassword bool, threads int) (stor
 		return fileStorage
 	}
 
-    urlRegex := regexp.MustCompile(`^(\w+)://([\w\-]+@)?([^/]+)(/(.+))?`)
+	if strings.HasPrefix(storageURL, "flat://") {
+		fileStorage, err := CreateFileStorage(storageURL[7:], false, threads)
+		if err != nil {
+			LOG_ERROR("STORAGE_CREATE", "Failed to load the file storage at %s: %v", storageURL, err)
+			return nil
+		}
+		return fileStorage
+	}
+
+	if strings.HasPrefix(storageURL, "samba://") {
+		fileStorage, err := CreateFileStorage(storageURL[8:], true, threads)
+		if err != nil {
+			LOG_ERROR("STORAGE_CREATE", "Failed to load the file storage at %s: %v", storageURL, err)
+			return nil
+		}
+		return fileStorage
+	}
+
+	// Added \! to matched[2] because OneDrive drive ids contain ! (e.g. "b!xxx")
+	urlRegex := regexp.MustCompile(`^([\w-]+)://([\w\-@\.\!]+@)?([^/]+)(/(.+))?`)
 
 	matched := urlRegex.FindStringSubmatch(storageURL)
 
 	if matched == nil {
 		LOG_ERROR("STORAGE_CREATE", "Unrecognizable storage URL: %s", storageURL)
 		return nil
-    } else if matched[1] == "sftp" {
+	} else if matched[1] == "sftp" || matched[1] == "sftpc" {
 		server := matched[3]
 		username := matched[2]
 		storageDir := matched[5]
@@ -180,6 +290,10 @@ func CreateStorage(preference Preference, resetPassword bool, threads int) (stor
 			username = username[:len(username)-1]
 		}
 
+		// If ssh_key_file is set, skip password-based login
+		keyFile := GetPasswordFromPreference(preference, "ssh_key_file")
+		passphrase := ""
+
 		password := ""
 		passwordCallback := func() (string, error) {
 			LOG_DEBUG("SSH_PASSWORD", "Attempting password login")
@@ -199,7 +313,6 @@ func CreateStorage(preference Preference, resetPassword bool, threads int) (stor
 			}
 		}
 
-        keyFile := ""
 		publicKeysCallback := func() ([]ssh.Signer, error) {
 			LOG_DEBUG("SSH_PUBLICKEY", "Attempting public key authentication")
 
@@ -215,6 +328,8 @@ func CreateStorage(preference Preference, resetPassword bool, threads int) (stor
 					signers, err = sshAgent.Signers()
 					if err != nil {
 						LOG_DEBUG("SSH_AGENT", "Can't log in using public key authentication via agent: %v", err)
+					} else if len(signers) == 0 {
+						LOG_DEBUG("SSH_AGENT", "SSH agent doesn't return any signer")
 					}
 				}
 			}
@@ -222,7 +337,7 @@ func CreateStorage(preference Preference, resetPassword bool, threads int) (stor
 			keyFile = GetPassword(preference, "ssh_key_file", "Enter the path of the private key file:",
 				true, resetPassword)
 
-            var key ssh.Signer
+			var keySigner ssh.Signer
 			var err error
 
 			if keyFile == "" {
@@ -233,15 +348,52 @@ func CreateStorage(preference Preference, resetPassword bool, threads int) (stor
 				if err != nil {
 					LOG_INFO("SSH_PUBLICKEY", "Failed to read the private key file: %v", err)
 				} else {
-                    key, err = ssh.ParsePrivateKey(content)
+					keySigner, err = ssh.ParsePrivateKey(content)
 					if err != nil {
+						if _, ok := err.(*ssh.PassphraseMissingError); ok {
+							LOG_TRACE("SSH_PUBLICKEY", "The private key file is encrypted")
+							passphrase = GetPassword(preference, "ssh_passphrase", "Enter the passphrase to decrypt the private key file:", false, resetPassword)
+							if len(passphrase) == 0 {
+								LOG_INFO("SSH_PUBLICKEY", "No passphrase to descrypt the private key file %s", keyFile)
+							} else {
+								keySigner, err = ssh.ParsePrivateKeyWithPassphrase(content, []byte(passphrase))
+								if err != nil {
+									LOG_INFO("SSH_PUBLICKEY", "Failed to parse the encrypted private key file %s: %v", keyFile, err)
+								}
+							}
+						} else {
 							LOG_INFO("SSH_PUBLICKEY", "Failed to parse the private key file %s: %v", keyFile, err)
 						}
 					}
+
+					if keySigner != nil {
+						certFile := keyFile + "-cert.pub"
+						if stat, err := os.Stat(certFile); err == nil && !stat.IsDir() {
+							LOG_DEBUG("SSH_CERTIFICATE", "Attempting to use ssh certificate from file %s", certFile)
+							var content []byte
+							content, err = ioutil.ReadFile(certFile)
+							if err != nil {
+								LOG_INFO("SSH_CERTIFICATE", "Failed to read ssh certificate file %s: %v", certFile, err)
+							} else {
+								pubKey, _, _, _, err := ssh.ParseAuthorizedKey(content)
+								if err != nil {
+									LOG_INFO("SSH_CERTIFICATE", "Failed parse ssh certificate file %s: %v", certFile, err)
+								} else {
+									certSigner, err := ssh.NewCertSigner(pubKey.(*ssh.Certificate), keySigner)
+									if err != nil {
+										LOG_INFO("SSH_CERTIFICATE", "Failed to create certificate signer: %v", err)
+									} else {
+										keySigner = certSigner
+									}
+								}
+							}
+						}
+					}
+				}
 			}
 
-            if key != nil {
-                signers = append(signers, key)
+			if keySigner != nil {
+				signers = append(signers, keySigner)
 			}
 
 			if len(signers) > 0 {
@@ -252,11 +404,19 @@ func CreateStorage(preference Preference, resetPassword bool, threads int) (stor
 
 		}
 
-        authMethods := [] ssh.AuthMethod {
+		authMethods := []ssh.AuthMethod{}
+		passwordAuthMethods := []ssh.AuthMethod{
 			ssh.PasswordCallback(passwordCallback),
 			ssh.KeyboardInteractive(keyboardInteractive),
+		}
+		keyFileAuthMethods := []ssh.AuthMethod{
 			ssh.PublicKeysCallback(publicKeysCallback),
 		}
+		if keyFile != "" {
+			authMethods = append(keyFileAuthMethods, passwordAuthMethods...)
+		} else {
+			authMethods = append(passwordAuthMethods, keyFileAuthMethods...)
+		}
 
 		if RunInBackground {
 
@@ -281,7 +441,7 @@ func CreateStorage(preference Preference, resetPassword bool, threads int) (stor
 			return checkHostKey(hostname, remote, key)
 		}
 
-        sftpStorage, err := CreateSFTPStorage(server, port, username, storageDir, authMethods, hostKeyChecker, threads)
+		sftpStorage, err := CreateSFTPStorage(matched[1] == "sftpc", server, port, username, storageDir, 2, authMethods, hostKeyChecker, threads)
 		if err != nil {
 			LOG_ERROR("STORAGE_CREATE", "Failed to load the SFTP storage at %s: %v", storageURL, err)
 			return nil
@@ -289,6 +449,9 @@ func CreateStorage(preference Preference, resetPassword bool, threads int) (stor
 
 		if keyFile != "" {
 			SavePassword(preference, "ssh_key_file", keyFile)
+			if passphrase != "" {
+				SavePassword(preference, "ssh_passphrase", passphrase)
+			}
 		} else if password != "" {
 			SavePassword(preference, "ssh_password", password)
 		}
@@ -340,10 +503,46 @@ func CreateStorage(preference Preference, resetPassword bool, threads int) (stor
 		SavePassword(preference, "s3_secret", secretKey)
 
 		return storage
+
+	} else if matched[1] == "wasabi" {
+
+		region := matched[2]
+		endpoint := matched[3]
+		bucket := matched[5]
+
+		if region != "" {
+			region = region[:len(region)-1]
+		}
+
+		key := GetPassword(preference, "wasabi_key",
+			"Enter Wasabi key:", true, resetPassword)
+		secret := GetPassword(preference, "wasabi_secret",
+			"Enter Wasabi secret:", true, resetPassword)
+
+		storageDir := ""
+		if strings.Contains(bucket, "/") {
+			firstSlash := strings.Index(bucket, "/")
+			storageDir = bucket[firstSlash+1:]
+			bucket = bucket[:firstSlash]
+		}
+
+		storage, err := CreateWasabiStorage(region, endpoint,
+			bucket, storageDir, key, secret, threads)
+
+		if err != nil {
+			LOG_ERROR("STORAGE_CREATE", "Failed to load the Wasabi storage at %s: %v", storageURL, err)
+			return nil
+		}
+
+		SavePassword(preference, "wasabi_key", key)
+		SavePassword(preference, "wasabi_secret", secret)
+
+		return storage
+
 	} else if matched[1] == "dropbox" {
 		storageDir := matched[3] + matched[5]
-        token := GetPassword(preference, "dropbox_token", "Enter Dropbox access token:", true, resetPassword)
-        dropboxStorage, err := CreateDropboxStorage(token, storageDir, threads)
+		token := GetPassword(preference, "dropbox_token", "Enter Dropbox refresh token:", true, resetPassword)
+		dropboxStorage, err := CreateDropboxStorage(token, storageDir, 1, threads)
 		if err != nil {
 			LOG_ERROR("STORAGE_CREATE", "Failed to load the dropbox storage: %v", err)
 			return nil
@@ -352,11 +551,30 @@ func CreateStorage(preference Preference, resetPassword bool, threads int) (stor
 		return dropboxStorage
 	} else if matched[1] == "b2" {
 		bucket := matched[3]
+		storageDir := matched[5]
 
-        accountID := GetPassword(preference, "b2_id", "Enter Backblaze Account ID:", true, resetPassword)
-        applicationKey := GetPassword(preference, "b2_key", "Enter Backblaze Application Key:", true, resetPassword)
+		accountID := GetPassword(preference, "b2_id", "Enter Backblaze account or application id:", true, resetPassword)
+		applicationKey := GetPassword(preference, "b2_key", "Enter corresponding Backblaze application key:", true, resetPassword)
 
-        b2Storage, err := CreateB2Storage(accountID, applicationKey, bucket, threads)
+		b2Storage, err := CreateB2Storage(accountID, applicationKey, "", bucket, storageDir, threads)
+		if err != nil {
+			LOG_ERROR("STORAGE_CREATE", "Failed to load the Backblaze B2 storage at %s: %v", storageURL, err)
+			return nil
+		}
+		SavePassword(preference, "b2_id", accountID)
+		SavePassword(preference, "b2_key", applicationKey)
+		return b2Storage
+	} else if matched[1] == "b2-custom" {
+		b2customUrlRegex := regexp.MustCompile(`^b2-custom://([^/]+)/([^/]+)(/(.+))?`)
+		matched := b2customUrlRegex.FindStringSubmatch(storageURL)
+		downloadURL := "https://" + matched[1]
+		bucket := matched[2]
+		storageDir := matched[4]
+
+		accountID := GetPassword(preference, "b2_id", "Enter Backblaze account or application id:", true, resetPassword)
+		applicationKey := GetPassword(preference, "b2_key", "Enter corresponding Backblaze application key:", true, resetPassword)
+
+		b2Storage, err := CreateB2Storage(accountID, applicationKey, downloadURL, bucket, storageDir, threads)
 		if err != nil {
 			LOG_ERROR("STORAGE_CREATE", "Failed to load the Backblaze B2 storage at %s: %v", storageURL, err)
 			return nil
@@ -407,26 +625,60 @@ func CreateStorage(preference Preference, resetPassword bool, threads int) (stor
 		SavePassword(preference, "gcs_token", tokenFile)
 		return gcsStorage
 	} else if matched[1] == "gcd" {
+		// Handle writing directly to the root of the drive
+		// For gcd://driveid@/, driveid@ is match[3] not match[2]
+		if matched[2] == "" && strings.HasSuffix(matched[3], "@") {
+			matched[2], matched[3]  = matched[3], matched[2]
+		}
+		driveID := matched[2]
+		if driveID != "" {
+			driveID = driveID[:len(driveID)-1]
+		}
 		storagePath := matched[3] + matched[4]
 		prompt := fmt.Sprintf("Enter the path of the Google Drive token file (downloadable from https://duplicacy.com/gcd_start):")
 		tokenFile := GetPassword(preference, "gcd_token", prompt, true, resetPassword)
-        gcdStorage, err := CreateGCDStorage(tokenFile, storagePath, threads)
+		gcdStorage, err := CreateGCDStorage(tokenFile, driveID, storagePath, threads)
 		if err != nil {
 			LOG_ERROR("STORAGE_CREATE", "Failed to load the Google Drive storage at %s: %v", storageURL, err)
 			return nil
 		}
 		SavePassword(preference, "gcd_token", tokenFile)
 		return gcdStorage
-    } else if matched[1] == "one" {
+	} else if matched[1] == "one" || matched[1] == "odb" {
+		// Handle writing directly to the root of the drive
+		// For odb://drive_id@/, drive_id@ is match[3] not match[2]
+		if matched[2] == "" && strings.HasSuffix(matched[3], "@") {
+			matched[2], matched[3]  = matched[3], matched[2]
+		}
+		drive_id := matched[2]
+		if len(drive_id) > 0 {
+			drive_id = drive_id[:len(drive_id)-1]
+		}
 		storagePath := matched[3] + matched[4]
 		prompt := fmt.Sprintf("Enter the path of the OneDrive token file (downloadable from https://duplicacy.com/one_start):")
-        tokenFile := GetPassword(preference, "one_token", prompt, true, resetPassword)
-        oneDriveStorage, err := CreateOneDriveStorage(tokenFile, storagePath, threads)
+		tokenFile := GetPassword(preference, matched[1] + "_token", prompt, true, resetPassword)
+
+		// client_id, just like tokenFile, can be stored in preferences
+		//prompt = fmt.Sprintf("Enter client_id for custom Azure app (if empty will use duplicacy.com one):")
+		client_id := GetPasswordFromPreference(preference, matched[1] + "_client_id")
+		client_secret := ""
+
+		if client_id != "" {
+			// client_secret should go into keyring
+			prompt = fmt.Sprintf("Enter client_secret for custom Azure app (if empty will use duplicacy.com one):")
+			client_secret = GetPassword(preference, matched[1] + "_client_secret", prompt, true, resetPassword)
+		}
+
+		oneDriveStorage, err := CreateOneDriveStorage(tokenFile, matched[1] == "odb", storagePath, threads, client_id, client_secret, drive_id)
 		if err != nil {
 			LOG_ERROR("STORAGE_CREATE", "Failed to load the OneDrive storage at %s: %v", storageURL, err)
 			return nil
 		}
-        SavePassword(preference, "one_token", tokenFile)
+
+		SavePassword(preference, matched[1] + "_token", tokenFile)
+		if client_id != "" {
+			SavePassword(preference, matched[1] + "_client_secret", client_secret)
+		}
 		return oneDriveStorage
 	} else if matched[1] == "hubic" {
 		storagePath := matched[3] + matched[4]
@@ -439,6 +691,111 @@ func CreateStorage(preference Preference, resetPassword bool, threads int) (stor
 		}
 		SavePassword(preference, "hubic_token", tokenFile)
 		return hubicStorage
+	} else if matched[1] == "swift" {
+		prompt := fmt.Sprintf("Enter the OpenStack Swift key:")
+		key := GetPassword(preference, "swift_key", prompt, true, resetPassword)
+		swiftStorage, err := CreateSwiftStorage(storageURL[8:], key, threads)
+		if err != nil {
+			LOG_ERROR("STORAGE_CREATE", "Failed to load the OpenStack Swift storage at %s: %v", storageURL, err)
+			return nil
+		}
+		SavePassword(preference, "swift_key", key)
+		return swiftStorage
+	} else if matched[1] == "webdav" || matched[1] == "webdav-http" {
+		server := matched[3]
+		username := matched[2]
+		if username == "" {
+			LOG_ERROR("STORAGE_CREATE", "No username is provided to access the WebDAV storage")
+			return nil
+		}
+		username = username[:len(username)-1]
+		storageDir := matched[5]
+		port := 0
+		useHTTP := matched[1] == "webdav-http"
+
+		if strings.Contains(server, ":") {
+			index := strings.Index(server, ":")
+			port, _ = strconv.Atoi(server[index+1:])
+			server = server[:index]
+		}
+
+		prompt := fmt.Sprintf("Enter the WebDAV password:")
+		password := GetPassword(preference, "webdav_password", prompt, true, resetPassword)
+		webDAVStorage, err := CreateWebDAVStorage(server, port, username, password, storageDir, useHTTP, threads)
+		if err != nil {
+			LOG_ERROR("STORAGE_CREATE", "Failed to load the WebDAV storage at %s: %v", storageURL, err)
+			return nil
+		}
+		SavePassword(preference, "webdav_password", password)
+		return webDAVStorage
+	} else if matched[1] == "fabric" {
+		endpoint := matched[3]
+		storageDir := matched[5]
+		prompt := fmt.Sprintf("Enter the token for accessing the Storage Made Easy File Fabric storage:")
+		token := GetPassword(preference, "fabric_token", prompt, true, resetPassword)
+		smeStorage, err := CreateFileFabricStorage(endpoint, token, storageDir, threads)
+		if err != nil {
+			LOG_ERROR("STORAGE_CREATE", "Failed to load the File Fabric storage at %s: %v", storageURL, err)
+			return nil
+		}
+		SavePassword(preference, "fabric_token", token)
+		return smeStorage
+	} else if matched[1] == "storj" {
+		satellite := matched[2] + matched[3]
+		bucket := matched[5]
+		storageDir := ""
+		index := strings.Index(bucket, "/")
+		if index >= 0 {
+			storageDir = bucket[index + 1:]
+			bucket = bucket[:index]
+		}
+		apiKey := GetPassword(preference, "storj_key", "Enter the API access key:", true, resetPassword)
+		passphrase := GetPassword(preference, "storj_passphrase", "Enter the passphrase:", true, resetPassword)
+		storjStorage, err := CreateStorjStorage(satellite, apiKey, passphrase, bucket, storageDir, threads)
+		if err != nil {
+			LOG_ERROR("STORAGE_CREATE", "Failed to load the Storj storage at %s: %v", storageURL, err)
+			return nil
+		}
+		SavePassword(preference, "storj_key", apiKey)
+		SavePassword(preference, "storj_passphrase", passphrase)
+		return storjStorage
+	} else if matched[1] == "smb" {
+		server := matched[3]
+		username := matched[2]
+		if username == "" {
+			LOG_ERROR("STORAGE_CREATE", "No username is provided to access the SAMBA storage")
+			return nil
+		}
+		username = username[:len(username)-1]
+		storageDir := matched[5]
+		port := 445
+
+		if strings.Contains(server, ":") {
+			index := strings.Index(server, ":")
+			port, _ = strconv.Atoi(server[index+1:])
+			server = server[:index]
+		}
+
+		if !strings.Contains(storageDir, "/") {
+			LOG_ERROR("STORAGE_CREATE", "No share name specified for the SAMBA storage")
+			return nil
+		}
+
+		index := strings.Index(storageDir, "/")
+		shareName := storageDir[:index]
+		storageDir = storageDir[index+1:]
+
+		prompt := fmt.Sprintf("Enter the SAMBA password:")
+		password := GetPassword(preference, "smb_password", prompt, true, resetPassword)
+		sambaStorage, err := CreateSambaStorage(server, port, username, password, shareName, storageDir, threads)
+		if err != nil {
+			LOG_ERROR("STORAGE_CREATE", "Failed to load the SAMBA storage at %s: %v", storageURL, err)
+			return nil
+		}
+		SavePassword(preference, "smb_password", password)
+		return sambaStorage
+
+
 	} else {
 		LOG_ERROR("STORAGE_CREATE", "The storage type '%s' is not supported", matched[1])
 		return nil

src/duplicacy_storage_test.go

@@ -5,96 +5,195 @@
 package duplicacy
 
 import (
-    "os"
-    "fmt"
-    "time"
-    "flag"
-    "path"
-    "testing"
-    "strings"
-    "strconv"
-    "io/ioutil"
 	"crypto/sha256"
 	"encoding/hex"
 	"encoding/json"
+	"flag"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"path"
 	"runtime/debug"
+	"strconv"
+	"testing"
+	"time"
 
 	crypto_rand "crypto/rand"
 	"math/rand"
 )
 
-var testStorageName string
-var testRateLimit int
-var testQuickMode bool
-var testThreads int
-var testFixedChunkSize bool
-
-func init() {
-    flag.StringVar(&testStorageName, "storage", "", "the test storage to use")
-    flag.IntVar(&testRateLimit, "limit-rate", 0, "maximum transfer speed in kbytes/sec")
-    flag.BoolVar(&testQuickMode, "quick", false, "quick test")
-    flag.IntVar(&testThreads, "threads", 1, "number of downloading/uploading threads")
-    flag.BoolVar(&testFixedChunkSize, "fixed-chunk-size", false, "fixed chunk size")
-    flag.Parse()
-}
+var testStorageName = flag.String("storage", "", "the test storage to use")
+var testRateLimit = flag.Int("limit-rate", 0, "maximum transfer speed in kbytes/sec")
+var testQuickMode = flag.Bool("quick", false, "quick test")
+var testThreads = flag.Int("threads", 1, "number of downloading/uploading threads")
+var testFixedChunkSize = flag.Bool("fixed-chunk-size", false, "fixed chunk size")
+var testRSAEncryption = flag.Bool("rsa", false, "enable RSA encryption")
+var testErasureCoding = flag.Bool("erasure-coding", false, "enable Erasure Coding")
 
 func loadStorage(localStoragePath string, threads int) (Storage, error) {
 
-    if testStorageName == "" || testStorageName == "file" {
-        return CreateFileStorage(localStoragePath, threads)
+	if *testStorageName == "" || *testStorageName == "file" {
+		storage, err := CreateFileStorage(localStoragePath, false, threads)
+		if storage != nil {
+			// Use a read level of at least 2 because this will catch more errors than a read level of 1.
+			storage.SetDefaultNestingLevels([]int{2, 3}, 2)
+		}
+		return storage, err
 	}
 
-    config, err := ioutil.ReadFile("test_storage.conf")
+	description, err := ioutil.ReadFile("test_storage.conf")
 	if err != nil {
 		return nil, err
 	}
 
-    storages := make(map[string]map[string]string)
+	configs := make(map[string]map[string]string)
 
-    err = json.Unmarshal(config, &storages)
+	err = json.Unmarshal(description, &configs)
 	if err != nil {
 		return nil, err
 	}
 
-    storage, found := storages[testStorageName]
+	config, found := configs[*testStorageName]
 	if !found {
-        return nil, fmt.Errorf("No storage named '%s' found", testStorageName)
+		return nil, fmt.Errorf("No storage named '%s' found", *testStorageName)
 	}
 
-    if testStorageName == "sftp" {
-        port, _ := strconv.Atoi(storage["port"])
-        return CreateSFTPStorageWithPassword(storage["server"], port, storage["username"], storage["directory"], storage["password"], threads)
-    } else if testStorageName == "s3" {
-        return CreateS3Storage(storage["region"], storage["endpoint"], storage["bucket"], storage["directory"], storage["access_key"], storage["secret_key"], threads, true, false)
-    } else if testStorageName == "s3c" {
-        return CreateS3CStorage(storage["region"], storage["endpoint"], storage["bucket"], storage["directory"], storage["access_key"], storage["secret_key"], threads)
-    } else if testStorageName == "minio" {
-        return CreateS3Storage(storage["region"], storage["endpoint"], storage["bucket"], storage["directory"], storage["access_key"], storage["secret_key"], threads, false, true)
-    } else if testStorageName == "minios" {
-        return CreateS3Storage(storage["region"], storage["endpoint"], storage["bucket"], storage["directory"], storage["access_key"], storage["secret_key"], threads, true, true)
-    } else if testStorageName == "dropbox" {
-        return CreateDropboxStorage(storage["token"], storage["directory"], threads)
-    } else if testStorageName == "b2" {
-        return CreateB2Storage(storage["account"], storage["key"], storage["bucket"], threads)
-    } else if testStorageName == "gcs-s3" {
-        return CreateS3Storage(storage["region"], storage["endpoint"], storage["bucket"], storage["directory"], storage["access_key"], storage["secret_key"], threads, true, false)
-    } else if testStorageName == "gcs" {
-        return CreateGCSStorage(storage["token_file"], storage["bucket"], storage["directory"], threads)
-    } else if testStorageName == "gcs-sa" {
-        return CreateGCSStorage(storage["token_file"], storage["bucket"], storage["directory"], threads)
-    } else if testStorageName == "azure" {
-        return CreateAzureStorage(storage["account"], storage["key"], storage["container"], threads)
-    } else if testStorageName == "acd" {
-        return CreateACDStorage(storage["token_file"], storage["storage_path"], threads)
-    } else if testStorageName == "gcd" {
-        return CreateGCDStorage(storage["token_file"], storage["storage_path"], threads)
-    } else if testStorageName == "one" {
-        return CreateOneDriveStorage(storage["token_file"], storage["storage_path"], threads)
-    } else if testStorageName == "hubic" {
-        return CreateHubicStorage(storage["token_file"], storage["storage_path"], threads)
-    } else {
-        return nil, fmt.Errorf("Invalid storage named: %s", testStorageName)
+	if *testStorageName == "flat" {
+		storage, err := CreateFileStorage(localStoragePath, false, threads)
+		storage.SetDefaultNestingLevels([]int{2, 3}, 2)
+		return storage, err
+	} else if *testStorageName == "samba" {
+		storage, err := CreateFileStorage(localStoragePath, true, threads)
+		storage.SetDefaultNestingLevels([]int{2, 3}, 2)
+		return storage, err
+	} else if *testStorageName == "sftp" {
+		port, _ := strconv.Atoi(config["port"])
+		storage, err := CreateSFTPStorageWithPassword(config["server"], port, config["username"], config["directory"], 2, config["password"], threads)
+		storage.SetDefaultNestingLevels([]int{2, 3}, 2)
+		return storage, err
+	} else if *testStorageName == "s3" {
+		storage, err := CreateS3Storage(config["region"], config["endpoint"], config["bucket"], config["directory"], config["access_key"], config["secret_key"], threads, true, false)
+		storage.SetDefaultNestingLevels([]int{2, 3}, 2)
+		return storage, err
+	} else if *testStorageName == "wasabi" {
+		storage, err := CreateWasabiStorage(config["region"], config["endpoint"], config["bucket"], config["directory"], config["access_key"], config["secret_key"], threads)
+		storage.SetDefaultNestingLevels([]int{2, 3}, 2)
+		return storage, err
+	} else if *testStorageName == "s3c" {
+		storage, err := CreateS3CStorage(config["region"], config["endpoint"], config["bucket"], config["directory"], config["access_key"], config["secret_key"], threads)
+		storage.SetDefaultNestingLevels([]int{2, 3}, 2)
+		return storage, err
+	} else if *testStorageName == "digitalocean" {
+		storage, err := CreateS3CStorage(config["region"], config["endpoint"], config["bucket"], config["directory"], config["access_key"], config["secret_key"], threads)
+		storage.SetDefaultNestingLevels([]int{2, 3}, 2)
+		return storage, err
+	} else if *testStorageName == "minio" {
+		storage, err := CreateS3Storage(config["region"], config["endpoint"], config["bucket"], config["directory"], config["access_key"], config["secret_key"], threads, false, true)
+		storage.SetDefaultNestingLevels([]int{2, 3}, 2)
+		return storage, err
+	} else if *testStorageName == "minios" {
+		storage, err := CreateS3Storage(config["region"], config["endpoint"], config["bucket"], config["directory"], config["access_key"], config["secret_key"], threads, true, true)
+		storage.SetDefaultNestingLevels([]int{2, 3}, 2)
+		return storage, err
+	} else if *testStorageName == "dropbox" {
+		storage, err := CreateDropboxStorage(config["token"], config["directory"], 1, threads)
+		storage.SetDefaultNestingLevels([]int{2, 3}, 2)
+		return storage, err
+	} else if *testStorageName == "b2" {
+		storage, err := CreateB2Storage(config["account"], config["key"], "", config["bucket"], config["directory"], threads)
+		storage.SetDefaultNestingLevels([]int{2, 3}, 2)
+		return storage, err
+	} else if *testStorageName == "gcs-s3" {
+		storage, err := CreateS3Storage(config["region"], config["endpoint"], config["bucket"], config["directory"], config["access_key"], config["secret_key"], threads, true, false)
+		storage.SetDefaultNestingLevels([]int{2, 3}, 2)
+		return storage, err
+	} else if *testStorageName == "gcs" {
+		storage, err := CreateGCSStorage(config["token_file"], config["bucket"], config["directory"], threads)
+		storage.SetDefaultNestingLevels([]int{2, 3}, 2)
+		return storage, err
+	} else if *testStorageName == "gcs-sa" {
+		storage, err := CreateGCSStorage(config["token_file"], config["bucket"], config["directory"], threads)
+		storage.SetDefaultNestingLevels([]int{2, 3}, 2)
+		return storage, err
+	} else if *testStorageName == "azure" {
+		storage, err := CreateAzureStorage(config["account"], config["key"], config["container"], threads)
+		storage.SetDefaultNestingLevels([]int{2, 3}, 2)
+		return storage, err
+	} else if *testStorageName == "acd" {
+		storage, err := CreateACDStorage(config["token_file"], config["storage_path"], threads)
+		storage.SetDefaultNestingLevels([]int{2, 3}, 2)
+		return storage, err
+	} else if *testStorageName == "gcd" {
+		storage, err := CreateGCDStorage(config["token_file"], "", config["storage_path"], threads)
+		storage.SetDefaultNestingLevels([]int{2, 3}, 2)
+		return storage, err
+	} else if *testStorageName == "gcd-shared" {
+		storage, err := CreateGCDStorage(config["token_file"], config["drive"], config["storage_path"], threads)
+		storage.SetDefaultNestingLevels([]int{2, 3}, 2)
+		return storage, err
+	} else if *testStorageName == "gcd-impersonate" {
+		storage, err := CreateGCDStorage(config["token_file"], config["drive"], config["storage_path"], threads)
+		storage.SetDefaultNestingLevels([]int{2, 3}, 2)
+		return storage, err
+	} else if *testStorageName == "one" {
+		storage, err := CreateOneDriveStorage(config["token_file"], false, config["storage_path"], threads, "", "", "")
+		storage.SetDefaultNestingLevels([]int{2, 3}, 2)
+		return storage, err
+	} else if *testStorageName == "odb" {
+		storage, err := CreateOneDriveStorage(config["token_file"], true, config["storage_path"], threads, "", "", "")
+		storage.SetDefaultNestingLevels([]int{2, 3}, 2)
+		return storage, err
+	} else if *testStorageName == "one" {
+		storage, err := CreateOneDriveStorage(config["token_file"], false, config["storage_path"], threads, "", "", "")
+		storage.SetDefaultNestingLevels([]int{2, 3}, 2)
+		return storage, err
+	} else if *testStorageName == "hubic" {
+		storage, err := CreateHubicStorage(config["token_file"], config["storage_path"], threads)
+		storage.SetDefaultNestingLevels([]int{2, 3}, 2)
+		return storage, err
+	} else if *testStorageName == "memset" {
+		storage, err := CreateSwiftStorage(config["storage_url"], config["key"], threads)
+		storage.SetDefaultNestingLevels([]int{2, 3}, 2)
+		return storage, err
+	} else if *testStorageName == "pcloud" || *testStorageName == "box" {
+		storage, err := CreateWebDAVStorage(config["host"], 0, config["username"], config["password"], config["storage_path"], false, threads)
+		if err != nil {
+			return nil, err
 		}
+		storage.SetDefaultNestingLevels([]int{2, 3}, 2)
+		return storage, err
+	} else if *testStorageName == "fabric" {
+		storage, err := CreateFileFabricStorage(config["endpoint"], config["token"], config["storage_path"], threads)
+		if err != nil {
+			return nil, err
+		}
+		storage.SetDefaultNestingLevels([]int{2, 3}, 2)
+		return storage, err
+	} else if *testStorageName == "storj" {
+		storage, err := CreateStorjStorage(config["satellite"], config["key"], config["passphrase"], config["bucket"], config["storage_path"], threads)
+		if err != nil {
+			return nil, err
+		}
+		storage.SetDefaultNestingLevels([]int{2, 3}, 2)
+		return storage, err
+	} else if *testStorageName == "storj" {
+		storage, err := CreateStorjStorage(config["satellite"], config["key"], config["passphrase"], config["bucket"], config["storage_path"], threads)
+		if err != nil {
+			return nil, err
+		}
+		storage.SetDefaultNestingLevels([]int{2, 3}, 2)
+		return storage, err
+	} else if *testStorageName == "smb" {
+		port, _ := strconv.Atoi(config["port"])
+		storage, err := CreateSambaStorage(config["server"], port, config["username"], config["password"], config["share"], config["storage_path"], threads)
+		if err != nil {
+			return nil, err
+		}
+		storage.SetDefaultNestingLevels([]int{2, 3}, 2)
+		return storage, err
+	}
+
+	return nil, fmt.Errorf("Invalid storage named: %s", *testStorageName)
 }
 
 func cleanStorage(storage Storage) {
@@ -234,15 +333,16 @@ func TestStorage(t *testing.T) {
 	os.RemoveAll(testDir)
 	os.MkdirAll(testDir, 0700)
 
-    LOG_INFO("STORAGE_TEST", "storage: %s", testStorageName)
+	LOG_INFO("STORAGE_TEST", "storage: %s", *testStorageName)
 
-    storage, err := loadStorage(testDir, 1)
+	threads := 8
+	storage, err := loadStorage(testDir, threads)
 	if err != nil {
 		t.Errorf("Failed to create storage: %v", err)
 		return
 	}
 	storage.EnableTestMode()
-    storage.SetRateLimits(testRateLimit, testRateLimit)
+	storage.SetRateLimits(*testRateLimit, *testRateLimit)
 
 	delay := 0
 	if _, ok := storage.(*ACDStorage); ok {
@@ -262,6 +362,33 @@ func TestStorage(t *testing.T) {
 
 	storage.CreateDirectory(0, "snapshots/repository1")
 	storage.CreateDirectory(0, "snapshots/repository2")
+
+	storage.CreateDirectory(0, "shared")
+
+	// Upload to the same directory by multiple goroutines
+	count := threads
+	finished := make(chan int, count)
+	for i := 0; i < count; i++ {
+		go func(threadIndex int, name string) {
+			err := storage.UploadFile(threadIndex, name, []byte("this is a test file"))
+			if err != nil {
+				t.Errorf("Error to upload '%s': %v", name, err)
+			}
+			finished <- 0
+		}(i, fmt.Sprintf("shared/a/b/c/%d", i))
+	}
+
+	for i := 0; i < count; i++ {
+		<-finished
+	}
+
+	for i := 0; i < count; i++ {
+		storage.DeleteFile(0, fmt.Sprintf("shared/a/b/c/%d", i))
+	}
+	storage.DeleteFile(0, "shared/a/b/c")
+	storage.DeleteFile(0, "shared/a/b")
+	storage.DeleteFile(0, "shared/a")
+
 	time.Sleep(time.Duration(delay) * time.Second)
 	{
 
@@ -334,10 +461,10 @@ func TestStorage(t *testing.T) {
 		}
 	}
 
-    numberOfFiles := 20
+	numberOfFiles := 10
 	maxFileSize := 64 * 1024
 
-    if testQuickMode {
+	if *testQuickMode {
 		numberOfFiles = 2
 	}
 
@@ -370,15 +497,7 @@ func TestStorage(t *testing.T) {
 			t.Errorf("Failed to upload the file %s: %v", filePath, err)
 			return
 		}
-        LOG_INFO("STORAGE_CHUNK", "Uploaded chunk: %s, size: %d", chunkID, len(content))
-    }
-
-    allChunks := [] string {}
-    for _, file := range listChunks(storage) {
-        file = strings.Replace(file, "/", "", -1)
-        if len(file) == 64 {
-            allChunks = append(allChunks, file)
-        }
+		LOG_INFO("STORAGE_CHUNK", "Uploaded chunk: %s, size: %d", filePath, len(content))
 	}
 
 	LOG_INFO("STORAGE_FOSSIL", "Making %s a fossil", chunks[0])
@@ -392,7 +511,6 @@ func TestStorage(t *testing.T) {
 
 	chunk := CreateChunk(config, true)
 
-
 	for _, chunkID := range chunks {
 
 		chunk.Reset(false)
@@ -409,7 +527,7 @@ func TestStorage(t *testing.T) {
 				t.Errorf("Error downloading file %s: %v", filePath, err)
 				continue
 			}
-            LOG_INFO("STORAGE_CHUNK", "Downloaded chunk: %s, size: %d", chunkID, chunk.GetLength())
+			LOG_INFO("STORAGE_CHUNK", "Downloaded chunk: %s, size: %d", filePath, chunk.GetLength())
 		}
 
 		hasher := sha256.New()
@@ -432,7 +550,7 @@ func TestStorage(t *testing.T) {
 	} else {
 		err = storage.DeleteFile(0, filePath)
 		if err != nil {
-            t.Errorf("Failed to delete file %s: %v", filePath)
+			t.Errorf("Failed to delete file %s: %v", filePath, err)
 		} else {
 			time.Sleep(time.Duration(delay) * time.Second)
 			filePath, exist, _, err = storage.FindChunk(0, chunks[1], true)
@@ -444,6 +562,11 @@ func TestStorage(t *testing.T) {
 		}
 	}
 
+	allChunks := []string{}
+	for _, file := range listChunks(storage) {
+		allChunks = append(allChunks, file)
+	}
+
 	for _, file := range allChunks {
 
 		err = storage.DeleteFile(0, "chunks/"+file)
@@ -454,3 +577,71 @@ func TestStorage(t *testing.T) {
 	}
 
 }
+
+func TestCleanStorage(t *testing.T) {
+	setTestingT(t)
+	SetLoggingLevel(INFO)
+
+	defer func() {
+		if r := recover(); r != nil {
+			switch e := r.(type) {
+			case Exception:
+				t.Errorf("%s %s", e.LogID, e.Message)
+				debug.PrintStack()
+			default:
+				t.Errorf("%v", e)
+				debug.PrintStack()
+			}
+		}
+	}()
+
+	testDir := path.Join(os.TempDir(), "duplicacy_test", "storage_test")
+	os.RemoveAll(testDir)
+	os.MkdirAll(testDir, 0700)
+
+	LOG_INFO("STORAGE_TEST", "storage: %s", *testStorageName)
+
+	storage, err := loadStorage(testDir, 1)
+	if err != nil {
+		t.Errorf("Failed to create storage: %v", err)
+		return
+	}
+
+	directories := make([]string, 0, 1024)
+	directories = append(directories, "snapshots/")
+	directories = append(directories, "chunks/")
+
+	for len(directories) > 0 {
+
+		dir := directories[len(directories)-1]
+		directories = directories[:len(directories)-1]
+
+		LOG_INFO("LIST_FILES", "Listing %s", dir)
+
+		files, _, err := storage.ListFiles(0, dir)
+		if err != nil {
+			LOG_ERROR("LIST_FILES", "Failed to list the directory %s: %v", dir, err)
+			return
+		}
+
+		for _, file := range files {
+			if len(file) > 0 && file[len(file)-1] == '/' {
+				directories = append(directories, dir+file)
+			} else {
+				storage.DeleteFile(0, dir+file)
+				LOG_INFO("DELETE_FILE", "Deleted file %s", file)
+			}
+		}
+	}
+
+	storage.DeleteFile(0, "config")
+	LOG_INFO("DELETE_FILE", "Deleted config")
+
+	files, _, err := storage.ListFiles(0, "chunks/")
+	for _, file := range files {
+		if len(file) > 0 && file[len(file)-1] != '/' {
+			LOG_DEBUG("FILE_EXIST", "File %s exists after deletion", file)
+		}
+	}
+
+}

src/duplicacy_storjstorage.go

@@ -0,0 +1,184 @@
+// Copyright (c) Acrosync LLC. All rights reserved.
+// Free for personal use and commercial trial
+// Commercial use requires per-user licenses available from https://duplicacy.com
+
+package duplicacy
+
+import (
+    "fmt"
+    "io"
+    "context"
+
+    "storj.io/uplink"
+)
+
+// StorjStorage is a storage backend for Storj.
+type StorjStorage struct {
+    StorageBase
+
+    project         *uplink.Project
+    bucket          string
+    storageDir      string
+    numberOfThreads int
+}
+
+// CreateStorjStorage creates a Storj storage.
+func CreateStorjStorage(satellite string, apiKey string, passphrase string,
+                        bucket string, storageDir string, threads int) (storage *StorjStorage, err error) {
+
+    ctx := context.Background()
+    access, err := uplink.RequestAccessWithPassphrase(ctx, satellite, apiKey, passphrase)
+    if err != nil {
+        return nil, fmt.Errorf("cannot request the access grant: %v", err)
+    }
+
+    project, err := uplink.OpenProject(ctx, access)
+    if err != nil {
+        return nil, fmt.Errorf("cannot open the project: %v", err)
+    }
+
+    _, err = project.StatBucket(ctx, bucket)
+    if err != nil {
+        return nil, fmt.Errorf("cannot found the bucket: %v", err)
+    }
+
+    if storageDir != "" && storageDir[len(storageDir) - 1] != '/' {
+        storageDir += "/"
+    }
+
+    storage = &StorjStorage {
+        project: project,
+        bucket: bucket,
+        storageDir: storageDir,
+        numberOfThreads: threads,
+    }
+
+    storage.DerivedStorage = storage
+    storage.SetDefaultNestingLevels([]int{2, 3}, 2)
+    return storage, nil
+}
+
+// ListFiles return the list of files and subdirectories under 'dir' (non-recursively).
+func (storage *StorjStorage) ListFiles(threadIndex int, dir string) (
+                                         files []string, sizes []int64, err error) {
+
+    fullPath := storage.storageDir + dir
+    if fullPath != "" && fullPath[len(fullPath) - 1] != '/' {
+        fullPath += "/"
+    }
+
+    options := uplink.ListObjectsOptions {
+        Prefix: fullPath,
+        System: true, // request SystemMetadata which includes ContentLength 
+    }
+    objects := storage.project.ListObjects(context.Background(), storage.bucket, &options)
+    for objects.Next() {
+        if objects.Err() != nil {
+            return nil, nil, objects.Err()
+        }
+        item := objects.Item()
+        name := item.Key[len(fullPath):]
+        size := item.System.ContentLength
+        if item.IsPrefix {
+            if name != "" && name[len(name) - 1] != '/' {
+                name += "/"
+                size = 0
+            }
+        }
+        files = append(files, name)
+        sizes = append(sizes, size)
+    }
+
+    return files, sizes, nil
+}
+
+// DeleteFile deletes the file or directory at 'filePath'.
+func (storage *StorjStorage) DeleteFile(threadIndex int, filePath string) (err error) {
+
+    _, err = storage.project.DeleteObject(context.Background(), storage.bucket,
+                                          storage.storageDir + filePath)
+    return err
+}
+
+// MoveFile renames the file.
+func (storage *StorjStorage) MoveFile(threadIndex int, from string, to string) (err error) {
+    err = storage.project.MoveObject(context.Background(), storage.bucket,
+                                     storage.storageDir + from, storage.bucket, storage.storageDir + to, nil)
+
+    return err
+}
+
+// CreateDirectory creates a new directory.
+func (storage *StorjStorage) CreateDirectory(threadIndex int, dir string) (err error) {
+    return nil
+}
+
+// GetFileInfo returns the information about the file or directory at 'filePath'.
+func (storage *StorjStorage) GetFileInfo(threadIndex int, filePath string) (
+                                         exist bool, isDir bool, size int64, err error) {
+    info, err := storage.project.StatObject(context.Background(), storage.bucket,
+                                            storage.storageDir + filePath)
+
+    if info == nil {
+        return false, false, 0, nil
+    } else if err != nil {
+        return false, false, 0, err
+    } else {
+        return true, info.IsPrefix, info.System.ContentLength, nil
+    }
+}
+
+// DownloadFile reads the file at 'filePath' into the chunk.
+func (storage *StorjStorage) DownloadFile(threadIndex int, filePath string, chunk *Chunk) (err error) {
+    file, err := storage.project.DownloadObject(context.Background(), storage.bucket,
+                                                storage.storageDir + filePath, nil)
+    if err != nil {
+        return err
+    }
+    defer file.Close()
+    
+    if _, err = RateLimitedCopy(chunk, file, storage.DownloadRateLimit/storage.numberOfThreads); err != nil {
+        return err
+    }
+
+    return nil    
+}
+
+// UploadFile writes 'content' to the file at 'filePath'
+func (storage *StorjStorage) UploadFile(threadIndex int, filePath string, content []byte) (err error) {
+
+    file, err := storage.project.UploadObject(context.Background(), storage.bucket,
+                                              storage.storageDir + filePath, nil)
+    if err != nil {
+        return err
+    }
+                                
+    reader := CreateRateLimitedReader(content, storage.UploadRateLimit/storage.numberOfThreads)
+    _, err = io.Copy(file, reader)
+    if err != nil {
+        return err
+    }
+
+    err = file.Commit()
+    if err != nil {
+        return err
+    }
+
+    return nil
+}
+
+// If a local snapshot cache is needed for the storage to avoid downloading/uploading chunks too often when
+// managing snapshots.
+func (storage *StorjStorage) IsCacheNeeded() bool { return true }
+
+// If the 'MoveFile' method is implemented.
+func (storage *StorjStorage) IsMoveFileImplemented() bool { return true }
+
+// If the storage can guarantee strong consistency.
+func (storage *StorjStorage) IsStrongConsistent() bool { return false }
+
+// If the storage supports fast listing of files names.
+func (storage *StorjStorage) IsFastListing() bool { return true }
+
+// Enable the test mode.
+func (storage *StorjStorage) EnableTestMode() {}

src/duplicacy_swiftstorage.go

@@ -0,0 +1,261 @@
+// Copyright (c) Acrosync LLC. All rights reserved.
+// Free for personal use and commercial trial
+// Commercial use requires per-user licenses available from https://duplicacy.com
+
+package duplicacy
+
+import (
+	"context"
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/ncw/swift/v2"
+)
+
+type SwiftStorage struct {
+	StorageBase
+
+	ctx        context.Context
+	connection *swift.Connection
+	container  string
+	storageDir string
+	threads    int
+}
+
+// CreateSwiftStorage creates an OpenStack Swift storage object.  storageURL is in the form of
+// `user@authURL/container/path?arg1=value1&arg2=value2``
+func CreateSwiftStorage(storageURL string, key string, threads int) (storage *SwiftStorage, err error) {
+
+	// This is the map to store all arguments
+	arguments := make(map[string]string)
+
+	// Check if there are arguments provided as a query string
+	if strings.Contains(storageURL, "?") {
+		urlAndArguments := strings.SplitN(storageURL, "?", 2)
+		storageURL = urlAndArguments[0]
+		for _, pair := range strings.Split(urlAndArguments[1], "&") {
+			if strings.Contains(pair, "=") {
+				keyAndValue := strings.Split(pair, "=")
+				arguments[keyAndValue[0]] = keyAndValue[1]
+			}
+		}
+	}
+
+	// Take out the user name if there is one
+	if strings.Contains(storageURL, "@") {
+		userAndURL := strings.Split(storageURL, "@")
+		arguments["user"] = userAndURL[0]
+		storageURL = userAndURL[1]
+	}
+
+	// The version is used to split authURL and container/path
+	versions := []string{"/v1/", "/v1.0/", "/v2/", "/v2.0/", "/v3/", "/v3.0/", "/v4/", "/v4.0/"}
+	storageDir := ""
+	for _, version := range versions {
+		if strings.Contains(storageURL, version) {
+			urlAndStorageDir := strings.SplitN(storageURL, version, 2)
+			storageURL = urlAndStorageDir[0] + version[0:len(version)-1]
+			storageDir = urlAndStorageDir[1]
+		}
+	}
+
+	// If no container/path is specified, find them from the arguments
+	if storageDir == "" {
+		storageDir = arguments["storage_dir"]
+	}
+
+	// Now separate the container name from the storage path
+	container := ""
+	if strings.Contains(storageDir, "/") {
+		containerAndStorageDir := strings.SplitN(storageDir, "/", 2)
+		container = containerAndStorageDir[0]
+		storageDir = containerAndStorageDir[1]
+		if len(storageDir) > 0 && storageDir[len(storageDir)-1] != '/' {
+			storageDir += "/"
+		}
+	} else {
+		container = storageDir
+		storageDir = ""
+	}
+
+	// Number of retries on err
+	retries := 4
+	if value, ok := arguments["retries"]; ok {
+		retries, _ = strconv.Atoi(value)
+	}
+
+	// Connect channel timeout
+	connectionTimeout := 10
+	if value, ok := arguments["connection_timeout"]; ok {
+		connectionTimeout, _ = strconv.Atoi(value)
+	}
+
+	// Data channel timeout
+	timeout := 60
+	if value, ok := arguments["timeout"]; ok {
+		timeout, _ = strconv.Atoi(value)
+	}
+
+	// Auth version; default to auto-detect
+	authVersion := 0
+	if value, ok := arguments["auth_version"]; ok {
+		authVersion, _ = strconv.Atoi(value)
+	}
+
+	// Allow http to be used by setting "protocol=http" in arguments
+	if _, ok := arguments["protocol"]; !ok {
+		arguments["protocol"] = "https"
+	}
+
+	ctx, _ := context.WithTimeout(context.Background(), time.Duration(timeout)*time.Second)
+
+	// Please refer to https://godoc.org/github.com/ncw/swift#Connection
+	connection := swift.Connection{
+		Domain:         arguments["domain"],
+		DomainId:       arguments["domain_id"],
+		UserName:       arguments["user"],
+		UserId:         arguments["user_id"],
+		ApiKey:         key,
+		AuthUrl:        arguments["protocol"] + "://" + storageURL,
+		Retries:        retries,
+		UserAgent:      arguments["user_agent"],
+		ConnectTimeout: time.Duration(connectionTimeout) * time.Second,
+		Timeout:        time.Duration(timeout) * time.Second,
+		Region:         arguments["region"],
+		AuthVersion:    authVersion,
+		Internal:       false,
+		Tenant:         arguments["tenant"],
+		TenantId:       arguments["tenant_id"],
+		EndpointType:   swift.EndpointType(arguments["endpiont_type"]),
+		TenantDomain:   arguments["tenant_domain"],
+		TenantDomainId: arguments["tenant_domain_id"],
+		TrustId:        arguments["trust_id"],
+	}
+
+	err = connection.Authenticate(ctx)
+	if err != nil {
+		return nil, err
+	}
+
+	_, _, err = connection.Container(ctx, container)
+	if err != nil {
+		return nil, err
+	}
+
+	storage = &SwiftStorage{
+		ctx:        ctx,
+		connection: &connection,
+		container:  container,
+		storageDir: storageDir,
+		threads:    threads,
+	}
+
+	storage.DerivedStorage = storage
+	storage.SetDefaultNestingLevels([]int{1}, 1)
+	return storage, nil
+}
+
+// ListFiles return the list of files and subdirectories under 'dir' (non-recursively)
+func (storage *SwiftStorage) ListFiles(threadIndex int, dir string) (files []string, sizes []int64, err error) {
+	if len(dir) > 0 && dir[len(dir)-1] != '/' {
+		dir += "/"
+	}
+	isSnapshotDir := dir == "snapshots/"
+	dir = storage.storageDir + dir
+
+	options := swift.ObjectsOpts{
+		Prefix: dir,
+		Limit:  1000,
+	}
+
+	if isSnapshotDir {
+		options.Delimiter = '/'
+	}
+
+	objects, err := storage.connection.ObjectsAll(storage.ctx, storage.container, &options)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	for _, obj := range objects {
+		if isSnapshotDir {
+			if obj.SubDir != "" {
+				files = append(files, obj.SubDir[len(dir):])
+				sizes = append(sizes, 0)
+			}
+		} else {
+			files = append(files, obj.Name[len(dir):])
+			sizes = append(sizes, obj.Bytes)
+		}
+	}
+
+	return files, sizes, nil
+}
+
+// DeleteFile deletes the file or directory at 'filePath'.
+func (storage *SwiftStorage) DeleteFile(threadIndex int, filePath string) (err error) {
+	return storage.connection.ObjectDelete(storage.ctx, storage.container, storage.storageDir+filePath)
+}
+
+// MoveFile renames the file.
+func (storage *SwiftStorage) MoveFile(threadIndex int, from string, to string) (err error) {
+	return storage.connection.ObjectMove(storage.ctx, storage.container, storage.storageDir+from,
+		storage.container, storage.storageDir+to)
+}
+
+// CreateDirectory creates a new directory.
+func (storage *SwiftStorage) CreateDirectory(threadIndex int, dir string) (err error) {
+	// Does nothing as directories do not exist in OpenStack Swift
+	return nil
+}
+
+// GetFileInfo returns the information about the file or directory at 'filePath'.
+func (storage *SwiftStorage) GetFileInfo(threadIndex int, filePath string) (exist bool, isDir bool, size int64, err error) {
+	object, _, err := storage.connection.Object(storage.ctx, storage.container, storage.storageDir+filePath)
+
+	if err != nil {
+		if err == swift.ObjectNotFound {
+			return false, false, 0, nil
+		} else {
+			return false, false, 0, err
+		}
+	}
+
+	return true, false, object.Bytes, nil
+}
+
+// DownloadFile reads the file at 'filePath' into the chunk.
+func (storage *SwiftStorage) DownloadFile(threadIndex int, filePath string, chunk *Chunk) (err error) {
+
+	file, _, err := storage.connection.ObjectOpen(storage.ctx, storage.container, storage.storageDir+filePath, false, nil)
+	if err != nil {
+		return err
+	}
+	_, err = RateLimitedCopy(chunk, file, storage.DownloadRateLimit/storage.threads)
+	return err
+}
+
+// UploadFile writes 'content' to the file at 'filePath'.
+func (storage *SwiftStorage) UploadFile(threadIndex int, filePath string, content []byte) (err error) {
+	reader := CreateRateLimitedReader(content, storage.UploadRateLimit/storage.threads)
+	_, err = storage.connection.ObjectPut(storage.ctx, storage.container, storage.storageDir+filePath, reader, true, "", "application/duplicacy", nil)
+	return err
+}
+
+// If a local snapshot cache is needed for the storage to avoid downloading/uploading chunks too often when
+// managing snapshots.
+func (storage *SwiftStorage) IsCacheNeeded() bool { return true }
+
+// If the 'MoveFile' method is implemented.
+func (storage *SwiftStorage) IsMoveFileImplemented() bool { return true }
+
+// If the storage can guarantee strong consistency.
+func (storage *SwiftStorage) IsStrongConsistent() bool { return false }
+
+// If the storage supports fast listing of files names.
+func (storage *SwiftStorage) IsFastListing() bool { return true }
+
+// Enable the test mode.
+func (storage *SwiftStorage) EnableTestMode() {
+}

src/duplicacy_utils.go

@@ -5,22 +5,19 @@
 package duplicacy
 
 import (
-    "fmt"
-    "os"
 	"bufio"
-    "io"
-    "io/ioutil"
-    "time"
-    "path"
-    "path/filepath"
-    "regexp"
-    "strings"
-    "strconv"
-    "runtime"
 	"crypto/sha256"
+	"fmt"
+	"io"
+	"os"
+	"regexp"
+	"strconv"
+	"strings"
+	"time"
+	"runtime"
 
-    "golang.org/x/crypto/pbkdf2"
 	"github.com/gilbertchen/gopass"
+	"golang.org/x/crypto/pbkdf2"
 )
 
 var RunInBackground bool = false
@@ -32,7 +29,17 @@ type RateLimitedReader struct {
 	StartTime time.Time
 }
 
-func CreateRateLimitedReader(content []byte, rate int) (*RateLimitedReader) {
+var RegexMap map[string]*regexp.Regexp
+
+func init() {
+
+	if RegexMap == nil {
+		RegexMap = make(map[string]*regexp.Regexp)
+	}
+
+}
+
+func CreateRateLimitedReader(content []byte, rate int) *RateLimitedReader {
 	return &RateLimitedReader{
 		Content: content,
 		Rate:    float64(rate * 1024),
@@ -40,7 +47,42 @@ func CreateRateLimitedReader(content []byte, rate int) (*RateLimitedReader) {
 	}
 }
 
-func (reader *RateLimitedReader) Length() (int64) {
+func IsEmptyFilter(pattern string) bool {
+	if pattern == "+" || pattern == "-" || pattern == "i:" || pattern == "e:" {
+		return true
+	} else {
+		return false
+	}
+}
+
+func IsUnspecifiedFilter(pattern string) bool {
+	if pattern[0] != '+' && pattern[0] != '-' && !strings.HasPrefix(pattern, "i:") && !strings.HasPrefix(pattern, "e:")  {
+		return true
+	} else {
+		return false
+	}
+}
+
+func IsValidRegex(pattern string) (valid bool, err error) {
+
+	var re *regexp.Regexp = nil
+
+	if re, valid = RegexMap[pattern]; valid && re != nil {
+		return true, nil
+	}
+
+	re, err = regexp.Compile(pattern)
+
+	if err != nil {
+		return false, err
+	} else {
+		RegexMap[pattern] = re
+		LOG_DEBUG("REGEX_STORED", "Saved compiled regex for pattern \"%s\", regex=%#v", pattern, re)
+		return true, err
+	}
+}
+
+func (reader *RateLimitedReader) Length() int64 {
 	return int64(len(reader.Content))
 }
 
@@ -115,14 +157,12 @@ func RateLimitedCopy(writer io.Writer, reader io.Reader, rate int) (written int6
 }
 
 // GenerateKeyFromPassword generates a key from the password.
-func GenerateKeyFromPassword(password string) []byte {
-    return pbkdf2.Key([]byte(password), DEFAULT_KEY, 16384, 32, sha256.New)
+func GenerateKeyFromPassword(password string, salt []byte, iterations int) []byte {
+	return pbkdf2.Key([]byte(password), salt, iterations, 32, sha256.New)
 }
 
-// GetPassword attempts to get the password from KeyChain/KeyRing, environment variables, or keyboard input.
-func GetPassword(preference Preference, passwordType string, prompt string,
-                 showPassword bool, resetPassword bool) (string) {
-
+// Get password from preference, env, but don't start any keyring request
+func GetPasswordFromPreference(preference Preference, passwordType string) string {
 	passwordID := passwordType
 	if preference.Name != "default" {
 		passwordID = preference.Name + "_" + passwordID
@@ -134,18 +174,53 @@ func GetPassword(preference Preference, passwordType string, prompt string,
 		if password, found := os.LookupEnv(name); found && password != "" {
 			return password
 		}
+
+		re := regexp.MustCompile(`[^a-zA-Z0-9_]`)
+		namePlain := re.ReplaceAllString(name, "_")
+		if namePlain != name {
+			LOG_DEBUG("PASSWORD_ENV_VAR", "Reading the environment variable %s", namePlain)
+			if password, found := os.LookupEnv(namePlain); found && password != "" {
+				return password
+			}
+		}
 	}
 
+	// If the password is stored in the preference, there is no need to include the storage name
+	// (i.e., preference.Name) in the key, so the key name should really be passwordType rather
+	// than passwordID; we're using passwordID here only for backward compatibility
 	if len(preference.Keys) > 0 && len(preference.Keys[passwordID]) > 0 {
-        LOG_DEBUG("PASSWORD_KEYCHAIN", "Reading %s from preferences", passwordID)
+		LOG_DEBUG("PASSWORD_PREFERENCE", "Reading %s from preferences", passwordID)
 		return preference.Keys[passwordID]
 	}
 
+	if len(preference.Keys) > 0 && len(preference.Keys[passwordType]) > 0 {
+		LOG_DEBUG("PASSWORD_PREFERENCE", "Reading %s from preferences", passwordType)
+		return preference.Keys[passwordType]
+	}
+
+	return ""
+}
+
+// GetPassword attempts to get the password from KeyChain/KeyRing, environment variables, or keyboard input.
+func GetPassword(preference Preference, passwordType string, prompt string,
+	showPassword bool, resetPassword bool) string {
+	passwordID := passwordType
+
+	preferencePassword := GetPasswordFromPreference(preference, passwordType)
+	if preferencePassword != "" {
+		return preferencePassword
+	}
+
+	if preference.Name != "default" {
+		passwordID = preference.Name + "_" + passwordID
+	}
+
 	if resetPassword && !RunInBackground {
 		keyringSet(passwordID, "")
 	} else {
 		password := keyringGet(passwordID)
 		if password != "" {
+			LOG_DEBUG("PASSWORD_KEYCHAIN", "Reading %s from keychain/keyring", passwordType)
 			return password
 		}
 
@@ -176,6 +251,7 @@ func GetPassword(preference Preference, passwordType string, prompt string,
 
 // SavePassword saves the specified password in the keyring/keychain.
 func SavePassword(preference Preference, passwordType string, password string) {
+
 	if password == "" || RunInBackground {
 		return
 	}
@@ -183,6 +259,12 @@ func SavePassword(preference Preference, passwordType string, password string) {
 	if preference.DoNotSavePassword {
 		return
 	}
+
+	// If the password is retrieved from env or preference, don't save it to keyring
+	if GetPasswordFromPreference(preference, passwordType) == password {
+		return
+	}
+
 	passwordID := passwordType
 	if preference.Name != "default" {
 		passwordID = preference.Name + "_" + passwordID
@@ -190,54 +272,6 @@ func SavePassword(preference Preference, passwordType string, password string) {
 	keyringSet(passwordID, password)
 }
 
-// RemoveEmptyDirectories remove all empty subdirectoreies under top.
-func RemoveEmptyDirectories(top string) {
-
-    stack := make([]string, 0, 256)
-
-    stack = append(stack, top)
-
-    for len(stack) > 0 {
-
-        dir := stack[len(stack) - 1]
-        stack = stack[:len(stack) - 1]
-
-        files, err := ioutil.ReadDir(dir)
-
-        if err != nil {
-            continue
-        }
-
-        for _, file := range files {
-            if file.IsDir() && file.Name()[0] != '.' {
-                stack = append(stack, path.Join(dir, file.Name()))
-            }
-        }
-
-        if len(files) == 0 {
-            if os.Remove(dir) != nil {
-                continue
-            }
-
-            dir = path.Dir(dir)
-            for (len(dir) > len(top)) {
-                files, err := ioutil.ReadDir(dir)
-                if err != nil {
-                    break
-                }
-
-                if len(files) == 0 {
-                    if os.Remove(dir) != nil {
-                        break;
-                    }
-                }
-                dir = path.Dir(dir)
-            }
-        }
-    }
-}
-
-
 // The following code was modified from the online article  'Matching Wildcards: An Algorithm', by Kirk J. Krauss,
 // Dr. Dobb's, August 26, 2008. However, the version in the article doesn't handle cases like matching 'abcccd'
 // against '*ccd', and the version here fixed that issue.
@@ -308,34 +342,62 @@ func matchPattern(text string, pattern string) bool {
 // include patterns, and included otherwise.
 func MatchPath(filePath string, patterns []string) (included bool) {
 
-    allIncludes := true
-    for _, pattern := range patterns {
+	var re *regexp.Regexp = nil
+	var found bool
+	var matched bool
 
+	allIncludes := true
+
+	for _, pattern := range patterns {
 		if pattern[0] == '+' {
 			if matchPattern(filePath, pattern[1:]) {
+				LOG_DEBUG("PATTERN_INCLUDE", "%s is included by pattern %s", filePath, pattern)
 				return true
 			}
 		} else if pattern[0] == '-' {
 			allIncludes = false
 			if matchPattern(filePath, pattern[1:]) {
+				LOG_DEBUG("PATTERN_EXCLUDE", "%s is excluded by pattern %s", filePath, pattern)
 				return false
 			}
+		} else if strings.HasPrefix(pattern, "i:") || strings.HasPrefix(pattern, "e:") {
+			if re, found = RegexMap[pattern[2:]]; found {
+				matched = re.MatchString(filePath)
+			} else {
+				re, err := regexp.Compile(pattern)
+				if err != nil {
+					LOG_ERROR("REGEX_ERROR", "Invalid regex encountered for pattern \"%s\" - %v", pattern[2:], err)
+				}
+				RegexMap[pattern] = re
+				matched = re.MatchString(filePath)
+			}
+			if matched {
+				if strings.HasPrefix(pattern, "i:") {
+					LOG_DEBUG("PATTERN_INCLUDE", "%s is included by pattern %s", filePath, pattern)
+					return true
+				} else {
+					LOG_DEBUG("PATTERN_EXCLUDE", "%s is excluded by pattern %s", filePath, pattern)
+					return false
+
+				}
+			} else {
+				if strings.HasPrefix(pattern, "e:") {
+					allIncludes = false
+				}
+			}
 		}
 	}
 
-    return !allIncludes
+	if allIncludes {
+		LOG_DEBUG("PATTERN_EXCLUDE", "%s is excluded", filePath)
+		return false
+	} else {
+		LOG_DEBUG("PATTERN_INCLUDE", "%s is included", filePath)
+		return true
+	}
 }
 
-func joinPath(components ...string) string {
-
-    combinedPath := path.Join(components...)
-    if len(combinedPath) > 257 && runtime.GOOS == "windows" {
-        combinedPath = `\\?\` + filepath.Join(components...)
-    }
-    return combinedPath
-}
-
-func PrettyNumber(number int64) (string) {
+func PrettyNumber(number int64) string {
 
 	G := int64(1024 * 1024 * 1024)
 	M := int64(1024 * 1024)
@@ -354,7 +416,7 @@ func PrettyNumber(number int64) (string) {
 	}
 }
 
-func PrettySize(size int64) (string) {
+func PrettySize(size int64) string {
 	if size > 1024*1024 {
 		return fmt.Sprintf("%.2fM", float64(size)/(1024.0*1024.0))
 	} else if size > 1024 {
@@ -364,7 +426,7 @@ func PrettySize(size int64) (string) {
 	}
 }
 
-func PrettyTime(seconds int64) (string) {
+func PrettyTime(seconds int64) string {
 
 	day := int64(3600 * 24)
 
@@ -373,14 +435,14 @@ func PrettyTime(seconds int64) (string) {
 			seconds/day, (seconds%day)/3600, (seconds%3600)/60, seconds%60)
 	} else if seconds > day {
 		return fmt.Sprintf("1 day %02d:%02d:%02d", (seconds%day)/3600, (seconds%3600)/60, seconds%60)
-    } else if seconds > 0 {
+	} else if seconds >= 0 {
 		return fmt.Sprintf("%02d:%02d:%02d", seconds/3600, (seconds%3600)/60, seconds%60)
 	} else {
 		return "n/a"
 	}
 }
 
-func AtoSize(sizeString string) (int) {
+func AtoSize(sizeString string) int {
 	sizeString = strings.ToLower(sizeString)
 
 	sizeRegex := regexp.MustCompile(`^([0-9]+)([mk])?$`)
@@ -399,3 +461,16 @@ func AtoSize(sizeString string) (int) {
 
 	return size
 }
+
+func PrintMemoryUsage() {
+
+	for {
+		var m runtime.MemStats
+		runtime.ReadMemStats(&m)
+
+		LOG_INFO("MEMORY_STATS", "Currently allocated: %s, total allocated: %s, system memory: %s, number of GCs: %d",
+		         PrettySize(int64(m.Alloc)), PrettySize(int64(m.TotalAlloc)), PrettySize(int64(m.Sys)), m.NumGC)
+
+		time.Sleep(time.Second)
+	}
+}

src/duplicacy_utils_darwin.go

@@ -0,0 +1,14 @@
+// Copyright (c) Acrosync LLC. All rights reserved.
+// Free for personal use and commercial trial
+// Commercial use requires per-user licenses available from https://duplicacy.com
+
+package duplicacy
+
+import (
+	"strings"
+)
+
+func excludedByAttribute(attirbutes map[string][]byte) bool {
+	value, ok := attirbutes["com.apple.metadata:com_apple_backup_excludeItem"]
+	return ok && strings.Contains(string(value), "com.apple.backupd")
+}

src/duplicacy_utils_freebsd.go

@@ -0,0 +1,13 @@
+// Copyright (c) Acrosync LLC. All rights reserved.
+// Free for personal use and commercial trial
+// Commercial use requires per-user licenses available from https://duplicacy.com
+
+package duplicacy
+
+import (
+)
+
+func excludedByAttribute(attirbutes map[string][]byte) bool {
+	_, ok := attirbutes["duplicacy_exclude"]
+	return ok
+}

src/duplicacy_utils_linux.go

@@ -0,0 +1,13 @@
+// Copyright (c) Acrosync LLC. All rights reserved.
+// Free for personal use and commercial trial
+// Commercial use requires per-user licenses available from https://duplicacy.com
+
+package duplicacy
+
+import (
+)
+
+func excludedByAttribute(attirbutes map[string][]byte) bool {
+	_, ok := attirbutes["duplicacy_exclude"]
+	return ok
+}

src/duplicacy_utils_others.go

@@ -7,12 +7,13 @@
 package duplicacy
 
 import (
-    "os"
 	"bytes"
-    "syscall"
+	"os"
+	"path"
 	"path/filepath"
+	"syscall"
 
-    "github.com/gilbertchen/xattr"
+	"github.com/pkg/xattr"
 )
 
 func Readlink(path string) (isRegular bool, s string, err error) {
@@ -31,11 +32,11 @@ func GetOwner(entry *Entry, fileInfo *os.FileInfo) {
 	}
 }
 
-func SetOwner(fullPath string, entry *Entry, fileInfo *os.FileInfo) (bool) {
+func SetOwner(fullPath string, entry *Entry, fileInfo *os.FileInfo) bool {
 	stat, ok := (*fileInfo).Sys().(*syscall.Stat_t)
 	if ok && stat != nil && (int(stat.Uid) != entry.UID || int(stat.Gid) != entry.GID) {
 		if entry.UID != -1 && entry.GID != -1 {
-            err := os.Chown(fullPath, entry.UID, entry.GID)
+			err := os.Lchown(fullPath, entry.UID, entry.GID)
 			if err != nil {
 				LOG_ERROR("RESTORE_CHOWN", "Failed to change uid or gid: %v", err)
 				return false
@@ -49,37 +50,46 @@ func SetOwner(fullPath string, entry *Entry, fileInfo *os.FileInfo) (bool) {
 func (entry *Entry) ReadAttributes(top string) {
 
 	fullPath := filepath.Join(top, entry.Path)
-    attributes, _ := xattr.Listxattr(fullPath)
+	attributes, _ := xattr.List(fullPath)
 	if len(attributes) > 0 {
-        entry.Attributes = make(map[string][]byte)
+		entry.Attributes = &map[string][]byte{}
 		for _, name := range attributes {
-            attribute, err := xattr.Getxattr(fullPath, name)
+			attribute, err := xattr.Get(fullPath, name)
 			if err == nil {
-                entry.Attributes[name] = attribute
+				(*entry.Attributes)[name] = attribute
 			}
 		}
 	}
 }
 
 func (entry *Entry) SetAttributesToFile(fullPath string) {
-    names, _ := xattr.Listxattr(fullPath)
+	names, _ := xattr.List(fullPath)
 
 	for _, name := range names {
 
-        newAttribute, found := entry.Attributes[name]
+
+		newAttribute, found := (*entry.Attributes)[name]
 		if found {
-            oldAttribute, _ := xattr.Getxattr(fullPath, name)
-            if bytes.Equal(oldAttribute, newAttribute) {
-                xattr.Setxattr(fullPath, name, newAttribute)
+			oldAttribute, _ := xattr.Get(fullPath, name)
+			if !bytes.Equal(oldAttribute, newAttribute) {
+				xattr.Set(fullPath, name, newAttribute)
 			}
-            delete(entry.Attributes, name)
+			delete(*entry.Attributes, name)
 		} else {
-            xattr.Removexattr(fullPath, name)
+			xattr.Remove(fullPath, name)
 		}
 	}
 
-    for name, attribute := range entry.Attributes {
-        xattr.Setxattr(fullPath, name, attribute)
+	for name, attribute := range *entry.Attributes {
+		xattr.Set(fullPath, name, attribute)
 	}
 
 }
+
+func joinPath(components ...string) string {
+	return path.Join(components...)
+}
+
+func SplitDir(fullPath string) (dir string, file string) {
+	return path.Split(fullPath)
+}

src/duplicacy_utils_test.go

@@ -5,15 +5,14 @@
 package duplicacy
 
 import (
+	"bytes"
 	"io"
 	"io/ioutil"
 	"time"
-    "bytes"
 
 	crypto_rand "crypto/rand"
 
 	"testing"
-
 )
 
 func TestMatchPattern(t *testing.T) {
@@ -93,6 +92,17 @@ func TestMatchPattern(t *testing.T) {
 		}
 	}
 
+	for _, pattern := range []string{ "+", "-", "i:", "e:", "+a", "-a", "i:a", "e:a"} {
+		if IsUnspecifiedFilter(pattern) {
+			t.Errorf("pattern %s has a specified filter", pattern)
+		}
+	}
+
+	for _, pattern := range []string{ "i", "e", "ia", "ib", "a", "b"} {
+		if !IsUnspecifiedFilter(pattern) {
+			t.Errorf("pattern %s does not have a specified filter", pattern)
+		}
+	}
 }
 
 func TestRateLimit(t *testing.T) {
@@ -113,7 +123,7 @@ func TestRateLimit(t *testing.T) {
 		return
 	}
 	if int(n) != len(content) {
-        t.Errorf("Wrote %s bytes instead of %s", n, len(content))
+		t.Errorf("Wrote %d bytes instead of %d", n, len(content))
 		return
 	}
 
@@ -128,7 +138,7 @@ func TestRateLimit(t *testing.T) {
 		return
 	}
 	if int(n) != len(content) {
-        t.Errorf("Copied %s bytes instead of %s", n, len(content))
+		t.Errorf("Copied %d bytes instead of %d", n, len(content))
 		return
 	}
 

src/duplicacy_utils_windows.go

@@ -5,8 +5,10 @@
 package duplicacy
 
 import (
-    "os"
 	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
 	"syscall"
 	"unsafe"
 )
@@ -36,6 +38,7 @@ type reparseDataBuffer struct {
 	// GenericReparseBuffer
 	reparseBuffer byte
 }
+
 const (
 	FSCTL_GET_REPARSE_POINT          = 0x900A8
 	MAXIMUM_REPARSE_DATA_BUFFER_SIZE = 16 * 1024
@@ -103,7 +106,7 @@ func GetOwner(entry *Entry, fileInfo *os.FileInfo) {
 	entry.GID = -1
 }
 
-func SetOwner(fullPath string, entry *Entry, fileInfo *os.FileInfo) (bool) {
+func SetOwner(fullPath string, entry *Entry, fileInfo *os.FileInfo) bool {
 	return true
 }
 
@@ -113,3 +116,22 @@ func (entry *Entry) ReadAttributes(top string) {
 func (entry *Entry) SetAttributesToFile(fullPath string) {
 
 }
+
+func joinPath(components ...string) string {
+
+	combinedPath := `\\?\` + filepath.Join(components...)
+	// If the path is on a samba drive we must use the UNC format
+	if strings.HasPrefix(combinedPath, `\\?\\\`) {
+		combinedPath = `\\?\UNC\` + combinedPath[6:]
+	}
+	return combinedPath
+}
+
+func SplitDir(fullPath string) (dir string, file string) {
+	i := strings.LastIndex(fullPath, "\\")
+	return fullPath[:i+1], fullPath[i+1:]
+}
+
+func excludedByAttribute(attirbutes map[string][]byte) bool {
+	return false
+}

src/duplicacy_wasabistorage.go

@@ -0,0 +1,192 @@
+//
+// Storage module for Wasabi (https://www.wasabi.com)
+//
+
+// Wasabi is nominally compatible with AWS S3, but the copy-and-delete
+// method used for renaming objects creates additional expense under
+// Wasabi's billing system.  This module is a pass-through to the
+// existing S3 module for everything other than that one operation.
+//
+// This module copyright 2017 Mark Feit (https://github.com/markfeit)
+// and may be distributed under the same terms as Duplicacy.
+
+package duplicacy
+
+import (
+	"crypto/hmac"
+	"crypto/sha1"
+	"encoding/base64"
+	"errors"
+	"fmt"
+	"net/http"
+	"time"
+)
+
+type WasabiStorage struct {
+	StorageBase
+
+	s3         *S3Storage
+	region     string
+	endpoint   string
+	bucket     string
+	storageDir string
+	key        string
+	secret     string
+	client     *http.Client
+}
+
+// See the Storage interface in duplicacy_storage.go for function
+// descriptions.
+
+func CreateWasabiStorage(
+	regionName string, endpoint string,
+	bucketName string, storageDir string,
+	accessKey string, secretKey string,
+	threads int,
+) (storage *WasabiStorage, err error) {
+
+	s3storage, error := CreateS3Storage(regionName, endpoint, bucketName,
+		storageDir, accessKey, secretKey, threads,
+		true,  // isSSLSupported
+		false, // isMinioCompatible
+	)
+
+	if err != nil {
+		return nil, error
+	}
+
+	wasabi := &WasabiStorage{
+
+		// Pass-through to existing S3 module
+		s3: s3storage,
+
+		// Local copies required for renaming
+		region:     regionName,
+		endpoint:   endpoint,
+		bucket:     bucketName,
+		storageDir: storageDir,
+		key:        accessKey,
+		secret:     secretKey,
+		client:     &http.Client{},
+	}
+
+	wasabi.DerivedStorage = wasabi
+	wasabi.SetDefaultNestingLevels([]int{0}, 0)
+
+	return wasabi, nil
+}
+
+func (storage *WasabiStorage) ListFiles(
+	threadIndex int, dir string,
+) (files []string, sizes []int64, err error) {
+	return storage.s3.ListFiles(threadIndex, dir)
+}
+
+func (storage *WasabiStorage) DeleteFile(
+	threadIndex int, filePath string,
+) (err error) {
+	return storage.s3.DeleteFile(threadIndex, filePath)
+
+}
+
+// This is a lightweight implementation of a call to Wasabi for a
+// rename.  It's designed to get the job done with as few dependencies
+// on other packages as possible rather than being somethng
+// general-purpose and reusable.
+func (storage *WasabiStorage) MoveFile(threadIndex int, from string, to string) (err error) {
+
+	var fromPath string
+	// The from path includes the bucket.  Take care not to include an empty storageDir
+	// string as Wasabi's backend will return 404 on URLs with double slashes.
+	if storage.storageDir == "" {
+		fromPath = fmt.Sprintf("/%s/%s", storage.bucket, from)
+	} else {
+		fromPath = fmt.Sprintf("/%s/%s/%s", storage.bucket, storage.storageDir, from)
+	}
+
+	object := fmt.Sprintf("https://%s@%s%s", storage.region, storage.endpoint, fromPath)
+
+	toPath := to
+	// The object's new name is relative to the top of the bucket.
+	if storage.storageDir != "" {
+		toPath = fmt.Sprintf("%s/%s", storage.storageDir, to)
+	}
+
+	timestamp := time.Now().Format(time.RFC1123Z)
+
+	signingString := fmt.Sprintf("MOVE\n\n\n%s\n%s", timestamp, fromPath)
+
+	signer := hmac.New(sha1.New, []byte(storage.secret))
+	signer.Write([]byte(signingString))
+
+	signature := base64.StdEncoding.EncodeToString(signer.Sum(nil))
+
+	authorization := fmt.Sprintf("AWS %s:%s", storage.key, signature)
+
+	request, err := http.NewRequest("MOVE", object, nil)
+	if err != nil {
+		return err
+	}
+	request.Header.Add("Authorization", authorization)
+	request.Header.Add("Date", timestamp)
+	request.Header.Add("Destination", toPath)
+	request.Header.Add("Host", storage.endpoint)
+	request.Header.Add("Overwrite", "true")
+
+	response, err := storage.client.Do(request)
+	if err != nil {
+		return err
+	}
+	defer response.Body.Close()
+
+	if response.StatusCode != 200 {
+		return errors.New(response.Status)
+	}
+
+	return nil
+}
+
+func (storage *WasabiStorage) CreateDirectory(
+	threadIndex int, dir string,
+) (err error) {
+	return storage.s3.CreateDirectory(threadIndex, dir)
+}
+
+func (storage *WasabiStorage) GetFileInfo(
+	threadIndex int, filePath string,
+) (exist bool, isDir bool, size int64, err error) {
+	return storage.s3.GetFileInfo(threadIndex, filePath)
+}
+
+func (storage *WasabiStorage) DownloadFile(
+	threadIndex int, filePath string, chunk *Chunk,
+) (err error) {
+	return storage.s3.DownloadFile(threadIndex, filePath, chunk)
+}
+
+func (storage *WasabiStorage) UploadFile(
+	threadIndex int, filePath string, content []byte,
+) (err error) {
+	return storage.s3.UploadFile(threadIndex, filePath, content)
+}
+
+func (storage *WasabiStorage) IsCacheNeeded() bool {
+	return storage.s3.IsCacheNeeded()
+}
+
+func (storage *WasabiStorage) IsMoveFileImplemented() bool {
+	// This is implemented locally since S3 does a copy and delete
+	return true
+}
+
+func (storage *WasabiStorage) IsStrongConsistent() bool {
+	// Wasabi has it, S3 doesn't.
+	return true
+}
+
+func (storage *WasabiStorage) IsFastListing() bool {
+	return storage.s3.IsFastListing()
+}
+
+func (storage *WasabiStorage) EnableTestMode() {
+}

src/duplicacy_webdavstorage.go

@@ -0,0 +1,485 @@
+// Copyright (c) Acrosync LLC. All rights reserved.
+// Free for personal use and commercial trial
+// Commercial use requires per-user licenses available from https://duplicacy.com
+//
+//
+// This storage backend is based on the work by Yuri Karamani from https://github.com/karamani/webdavclnt,
+// released under the MIT license.
+//
+package duplicacy
+
+import (
+	"bytes"
+	"encoding/xml"
+	"errors"
+	"fmt"
+	"io"
+	"math/rand"
+	"net/http"
+	//"net/http/httputil"
+	"strconv"
+	"strings"
+	"sync"
+	"time"
+	"io/ioutil"
+)
+
+type WebDAVStorage struct {
+	StorageBase
+
+	host       string
+	port       int
+	username   string
+	password   string
+	storageDir string
+	useHTTP    bool
+
+	client             *http.Client
+	threads            int
+	directoryCache     map[string]int // stores directories known to exist by this backend
+	directoryCacheLock sync.Mutex     // lock for accessing directoryCache
+}
+
+var (
+	errWebDAVAuthorizationFailure = errors.New("Authentication failed")
+	errWebDAVMovedPermanently     = errors.New("Moved permanently")
+	errWebDAVNotExist             = errors.New("Path does not exist")
+	errWebDAVMaximumBackoff       = errors.New("Maximum backoff reached")
+	errWebDAVMethodNotAllowed     = errors.New("Method not allowed")
+)
+
+func CreateWebDAVStorage(host string, port int, username string, password string, storageDir string, useHTTP bool, threads int) (storage *WebDAVStorage, err error) {
+	if len(storageDir) > 0 && storageDir[len(storageDir)-1] != '/' {
+		storageDir += "/"
+	}
+
+	storage = &WebDAVStorage{
+		host:       host,
+		port:       port,
+		username:   username,
+		password:   password,
+		storageDir: "",
+		useHTTP:    useHTTP,
+
+		client:         http.DefaultClient,
+		threads:        threads,
+		directoryCache: make(map[string]int),
+	}
+
+	// Make sure it doesn't follow redirect
+	storage.client.CheckRedirect = func(req *http.Request, via []*http.Request) error {
+		return http.ErrUseLastResponse
+	}
+
+	exist, isDir, _, err := storage.GetFileInfo(0, storageDir)
+	if err != nil {
+		return nil, err
+	}
+	if !exist {
+		return nil, fmt.Errorf("Storage path %s does not exist", storageDir)
+	}
+	if !isDir {
+		return nil, fmt.Errorf("Storage path %s is not a directory", storageDir)
+	}
+	storage.storageDir = storageDir
+
+	for _, dir := range []string{"snapshots", "chunks"} {
+		storage.CreateDirectory(0, dir)
+	}
+
+	storage.DerivedStorage = storage
+	storage.SetDefaultNestingLevels([]int{0}, 0)
+	return storage, nil
+}
+
+func (storage *WebDAVStorage) createConnectionString(uri string) string {
+
+	url := storage.host
+
+	if storage.useHTTP {
+		url = "http://" + url
+	} else {
+		url = "https://" + url
+	}
+
+	if storage.port > 0 {
+		url += fmt.Sprintf(":%d", storage.port)
+	}
+	return url + "/" + storage.storageDir + uri
+}
+
+func (storage *WebDAVStorage) retry(backoff int) int {
+	delay := rand.Intn(backoff*500) + backoff*500
+	time.Sleep(time.Duration(delay) * time.Millisecond)
+	backoff *= 2
+	return backoff
+}
+
+func (storage *WebDAVStorage) sendRequest(method string, uri string, depth int, data []byte) (io.ReadCloser, http.Header, error) {
+
+	backoff := 1
+	for i := 0; i < 8; i++ {
+
+		var dataReader io.Reader
+		headers := make(map[string]string)
+		if method == "PROPFIND" {
+			headers["Content-Type"] = "application/xml"
+			headers["Depth"] = fmt.Sprintf("%d", depth)
+			dataReader = bytes.NewReader(data)
+		} else if method == "PUT" {
+			headers["Content-Type"] = "application/octet-stream"
+			headers["Content-Length"] = fmt.Sprintf("%d", len(data))
+			if storage.UploadRateLimit <= 0 {
+				dataReader = bytes.NewReader(data)
+			} else {
+				dataReader = CreateRateLimitedReader(data, storage.UploadRateLimit/storage.threads)
+			}
+		} else if method == "MOVE" {
+			headers["Destination"] = storage.createConnectionString(string(data))
+			headers["Content-Type"] = "application/octet-stream"
+			dataReader = bytes.NewReader([]byte(""))
+		} else {
+			headers["Content-Type"] = "application/octet-stream"
+			dataReader = bytes.NewReader(data)
+		}
+
+		request, err := http.NewRequest(method, storage.createConnectionString(uri), dataReader)
+		if err != nil {
+			return nil, nil, err
+		}
+
+		if len(storage.username) > 0 {
+			request.SetBasicAuth(storage.username, storage.password)
+		}
+
+		for key, value := range headers {
+			request.Header.Set(key, value)
+		}
+
+		if method == "PUT" {
+			request.ContentLength = int64(len(data))
+		}
+
+		//requestDump, err := httputil.DumpRequest(request, true)
+		//LOG_INFO("debug", "Request: %s", requestDump)
+
+		response, err := storage.client.Do(request)
+		if err != nil {
+			LOG_TRACE("WEBDAV_ERROR", "URL request '%s %s' returned an error (%v)", method, uri, err)
+			backoff = storage.retry(backoff)
+			continue
+		}
+
+		if response.StatusCode < 300 {
+			return response.Body, response.Header, nil
+		}
+
+		io.Copy(ioutil.Discard, response.Body)
+		response.Body.Close()
+
+		if response.StatusCode == 301 {
+			return nil, nil, errWebDAVMovedPermanently
+		}
+
+		if response.StatusCode == 404 {
+			// Retry if it is UPLOAD, otherwise return immediately
+			if method != "PUT" {
+				return nil, nil, errWebDAVNotExist
+			}
+		} else if response.StatusCode == 405 {
+			return nil, nil, errWebDAVMethodNotAllowed
+		}
+		LOG_INFO("WEBDAV_RETRY", "URL request '%s %s' returned status code %d", method, uri, response.StatusCode)
+		backoff = storage.retry(backoff)
+	}
+	return nil, nil, errWebDAVMaximumBackoff
+}
+
+type WebDAVProperties map[string]string
+
+type WebDAVPropValue struct {
+	XMLName xml.Name `xml:""`
+	Value   string   `xml:",innerxml"`
+}
+
+type WebDAVProp struct {
+	PropList []WebDAVPropValue `xml:",any"`
+}
+
+type WebDAVPropStat struct {
+	Prop *WebDAVProp `xml:"prop"`
+}
+
+type WebDAVResponse struct {
+	Href     string          `xml:"href"`
+	PropStat *WebDAVPropStat `xml:"propstat"`
+}
+
+type WebDAVMultiStatus struct {
+	Responses []WebDAVResponse `xml:"response"`
+}
+
+func (storage *WebDAVStorage) getProperties(uri string, depth int, properties ...string) (map[string]WebDAVProperties, error) {
+
+	maxTries := 3
+	for tries := 0; ; tries++ {
+		propfind := "<prop>"
+		for _, p := range properties {
+			propfind += fmt.Sprintf("<%s/>", p)
+		}
+		propfind += "</prop>"
+
+		body := fmt.Sprintf(`<?xml version="1.0" encoding="utf-8" ?><propfind xmlns="DAV:">%s</propfind>`, propfind)
+
+		readCloser, _, err := storage.sendRequest("PROPFIND", uri, depth, []byte(body))
+		if err != nil {
+			return nil, err
+		}
+		defer readCloser.Close()
+		defer io.Copy(ioutil.Discard, readCloser)
+
+		object := WebDAVMultiStatus{}
+		err = xml.NewDecoder(readCloser).Decode(&object)
+		if err != nil {
+			if strings.Contains(err.Error(), "unexpected EOF") && tries < maxTries {
+				LOG_WARN("WEBDAV_RETRY", "Retrying on %v", err)
+				continue
+			}
+			return nil, err
+		}
+
+		if object.Responses == nil || len(object.Responses) == 0 {
+			return nil, errors.New("no WebDAV responses")
+		}
+
+		responses := make(map[string]WebDAVProperties)
+
+		for _, responseTag := range object.Responses {
+
+			if responseTag.PropStat == nil || responseTag.PropStat.Prop == nil || responseTag.PropStat.Prop.PropList == nil {
+				return nil, errors.New("no WebDAV properties")
+			}
+
+			properties := make(WebDAVProperties)
+			for _, prop := range responseTag.PropStat.Prop.PropList {
+				properties[prop.XMLName.Local] = prop.Value
+			}
+
+			responseKey := responseTag.Href
+			responses[responseKey] = properties
+
+		}
+
+		return responses, nil
+	}
+}
+
+// ListFiles return the list of files and subdirectories under 'dir'.  A subdirectories returned must have a trailing '/', with
+// a size of 0.  If 'dir' is 'snapshots', only subdirectories will be returned.  If 'dir' is 'snapshots/repository_id', then only
+// files will be returned.  If 'dir' is 'chunks', the implementation can return the list either recusively or non-recusively.
+func (storage *WebDAVStorage) ListFiles(threadIndex int, dir string) (files []string, sizes []int64, err error) {
+	if dir[len(dir)-1] != '/' {
+		dir += "/"
+	}
+	properties, err := storage.getProperties(dir, 1, "getcontentlength", "resourcetype")
+	if err != nil {
+		return nil, nil, err
+	}
+
+	prefixLength := len(storage.storageDir) + len(dir) + 1
+
+	for file, m := range properties {
+		if len(file) <= prefixLength {
+			continue
+		}
+
+		isDir := false
+		size := 0
+		if resourceType, exist := m["resourcetype"]; exist && strings.Contains(resourceType, "collection") {
+			isDir = true
+		} else if length, exist := m["getcontentlength"]; exist {
+			if length == "" {
+				isDir = true
+			} else {
+				size, _ = strconv.Atoi(length)
+			}
+		} else {
+			continue
+		}
+
+		if !isDir {
+			if dir != "snapshots/" {
+				files = append(files, file[prefixLength:])
+				sizes = append(sizes, int64(size))
+			}
+		} else {
+			// This is a dir
+			file := file[prefixLength:]
+			if file[len(file)-1] != '/' {
+				file += "/"
+			}
+			files = append(files, file)
+			sizes = append(sizes, int64(0))
+
+			// Add the directory to the directory cache
+			storage.directoryCacheLock.Lock()
+			storage.directoryCache[dir + file] = 1
+			storage.directoryCacheLock.Unlock()
+
+		}
+	}
+
+	return files, sizes, nil
+}
+
+// GetFileInfo returns the information about the file or directory at 'filePath'.
+func (storage *WebDAVStorage) GetFileInfo(threadIndex int, filePath string) (exist bool, isDir bool, size int64, err error) {
+
+	properties, err := storage.getProperties(filePath, 0, "getcontentlength", "resourcetype")
+	if err != nil {
+		if err == errWebDAVNotExist {
+			return false, false, 0, nil
+		}
+		if err == errWebDAVMovedPermanently {
+			// This must be a directory
+			return true, true, 0, nil
+		}
+		return false, false, 0, err
+	}
+
+	m, exist := properties["/"+storage.storageDir+filePath]
+
+	// If no properties exist for the given filePath, remove the trailing / from filePath and search again
+	if !exist && filePath != "" && filePath[len(filePath) - 1] == '/' {
+		m, exist = properties["/"+storage.storageDir+filePath[:len(filePath) - 1]]
+	}
+
+	if !exist {
+		return false, false, 0, nil
+	} else if resourceType, exist := m["resourcetype"]; exist && strings.Contains(resourceType, "collection") {
+		return true, true, 0, nil
+	} else if length, exist := m["getcontentlength"]; exist && length != "" {
+		value, _ := strconv.Atoi(length)
+		return true, false, int64(value), nil
+	} else {
+		return true, true, 0, nil
+	}
+}
+
+// DeleteFile deletes the file or directory at 'filePath'.
+func (storage *WebDAVStorage) DeleteFile(threadIndex int, filePath string) (err error) {
+	readCloser, _, err := storage.sendRequest("DELETE", filePath, 0, []byte(""))
+	if err != nil {
+		return err
+	}
+	io.Copy(ioutil.Discard, readCloser)
+	readCloser.Close()
+	return nil
+}
+
+// MoveFile renames the file.
+func (storage *WebDAVStorage) MoveFile(threadIndex int, from string, to string) (err error) {
+	readCloser, _, err := storage.sendRequest("MOVE", from, 0, []byte(to))
+	if err != nil {
+		return err
+	}
+	io.Copy(ioutil.Discard, readCloser)
+	readCloser.Close()
+	return nil
+}
+
+// createParentDirectory creates the parent directory if it doesn't exist in the cache
+func (storage *WebDAVStorage) createParentDirectory(threadIndex int, dir string) (err error) {
+
+	found := strings.LastIndex(dir, "/")
+	if found == -1 {
+		return nil
+	}
+	parent := dir[:found]
+
+	return storage.CreateDirectory(threadIndex, parent)
+}
+
+// CreateDirectory creates a new directory.
+func (storage *WebDAVStorage) CreateDirectory(threadIndex int, dir string) (err error) {
+	for dir != "" && dir[len(dir)-1] == '/' {
+		dir = dir[:len(dir)-1]
+	}
+
+	if dir == "" {
+		return nil
+	}
+
+	storage.directoryCacheLock.Lock()
+	_, exist := storage.directoryCache[dir]
+	storage.directoryCacheLock.Unlock()
+
+	if exist {
+		return nil
+	}
+
+	// If there is an error in creating the parent directory, proceed anyway
+	storage.createParentDirectory(threadIndex, dir)
+
+	readCloser, _, err := storage.sendRequest("MKCOL", dir, 0, []byte(""))
+	if err != nil {
+		if err == errWebDAVMethodNotAllowed || err == errWebDAVMovedPermanently || err == io.EOF {
+			// We simply ignore these errors and assume that the directory already exists
+			LOG_TRACE("WEBDAV_MKDIR", "Can't create directory %s: %v; error ignored", dir, err)
+			storage.directoryCacheLock.Lock()
+			storage.directoryCache[dir] = 1
+			storage.directoryCacheLock.Unlock()
+			return nil
+		}
+		return err
+	}
+	io.Copy(ioutil.Discard, readCloser)
+	readCloser.Close()
+
+	storage.directoryCacheLock.Lock()
+	storage.directoryCache[dir] = 1
+	storage.directoryCacheLock.Unlock()
+	return nil
+}
+
+// DownloadFile reads the file at 'filePath' into the chunk.
+func (storage *WebDAVStorage) DownloadFile(threadIndex int, filePath string, chunk *Chunk) (err error) {
+	readCloser, _, err := storage.sendRequest("GET", filePath, 0, nil)
+	if err != nil {
+		return err
+	}
+
+	_, err = RateLimitedCopy(chunk, readCloser, storage.DownloadRateLimit/storage.threads)
+	return err
+}
+
+// UploadFile writes 'content' to the file at 'filePath'.
+func (storage *WebDAVStorage) UploadFile(threadIndex int, filePath string, content []byte) (err error) {
+
+	// If there is an error in creating the parent directory, proceed anyway
+	storage.createParentDirectory(threadIndex, filePath)
+
+	readCloser, _, err := storage.sendRequest("PUT", filePath, 0, content)
+	if err != nil {
+		return err
+	}
+	io.Copy(ioutil.Discard, readCloser)
+	readCloser.Close()
+	return nil
+}
+
+// If a local snapshot cache is needed for the storage to avoid downloading/uploading chunks too often when
+// managing snapshots.
+func (storage *WebDAVStorage) IsCacheNeeded() bool { return true }
+
+// If the 'MoveFile' method is implemented.
+func (storage *WebDAVStorage) IsMoveFileImplemented() bool { return true }
+
+// If the storage can guarantee strong consistency.
+func (storage *WebDAVStorage) IsStrongConsistent() bool { return false }
+
+// If the storage supports fast listing of files names.
+func (storage *WebDAVStorage) IsFastListing() bool { return false }
+
+// Enable the test mode.
+func (storage *WebDAVStorage) EnableTestMode() {}