mount: factor filesystem code into mountlib and mounttest

cmd/mountlib/fs.go

@@ -0,0 +1,116 @@
+package mountlib
+
+import (
+	"strings"
+	"sync/atomic"
+	"time"
+
+	"github.com/ncw/rclone/fs"
+)
+
+// Node represents either a *Dir or a *File
+type Node interface {
+	IsFile() bool
+	Inode() uint64
+}
+
+var (
+	_ Node = (*File)(nil)
+	_ Node = (*Dir)(nil)
+)
+
+// Noder represents something which can return a node
+type Noder interface {
+	Node() Node
+}
+
+var (
+	_ Noder = (*File)(nil)
+	_ Noder = (*Dir)(nil)
+	_ Noder = (*ReadFileHandle)(nil)
+	_ Noder = (*WriteFileHandle)(nil)
+)
+
+// FS represents the top level filing system
+type FS struct {
+	f      fs.Fs
+	root   *Dir
+	noSeek bool // don't allow seeking if set
+}
+
+// NewFS creates a new filing system and root directory
+func NewFS(f fs.Fs) *FS {
+	fsDir := &fs.Dir{
+		Name: "",
+		When: time.Now(),
+	}
+	fsys := &FS{
+		f: f,
+	}
+	fsys.root = newDir(fsys, f, fsDir)
+	return fsys
+}
+
+// NoSeek disables seeking of files
+func (fsys *FS) NoSeek() *FS {
+	fsys.noSeek = true
+	return fsys
+}
+
+// Root returns the root node
+func (fsys *FS) Root() (*Dir, error) {
+	fs.Debugf(fsys.f, "Root()")
+	return fsys.root, nil
+}
+
+var inodeCount uint64
+
+// NewInode creates a new unique inode number
+func NewInode() (inode uint64) {
+	return atomic.AddUint64(&inodeCount, 1)
+}
+
+// Lookup finds the Node by path starting from the root
+func (f *FS) Lookup(path string) (node Node, err error) {
+	node = f.root
+	for path != "" {
+		i := strings.IndexRune(path, '/')
+		var name string
+		if i < 0 {
+			name, path = path, ""
+		} else {
+			name, path = path[:i], path[i+1:]
+		}
+		if name == "" {
+			continue
+		}
+		dir, ok := node.(*Dir)
+		if !ok {
+			// We need to look in a directory, but found a file
+			return nil, ENOENT
+		}
+		node, err = dir.Lookup(name)
+		if err != nil {
+			return nil, err
+		}
+	}
+	return
+}
+
+// Statfs is called to obtain file system metadata.
+// It should write that data to resp.
+func (f *FS) Statfs() error {
+	/* FIXME
+	const blockSize = 4096
+	const fsBlocks = (1 << 50) / blockSize
+	resp.Blocks = fsBlocks  // Total data blocks in file system.
+	resp.Bfree = fsBlocks   // Free blocks in file system.
+	resp.Bavail = fsBlocks  // Free blocks in file system if you're not root.
+	resp.Files = 1E9        // Total files in file system.
+	resp.Ffree = 1E9        // Free files in file system.
+	resp.Bsize = blockSize  // Block size
+	resp.Namelen = 255      // Maximum file name length?
+	resp.Frsize = blockSize // Fragment size, smallest addressable data size in the file system.
+	*/
+	return nil
+}