vendor: update all dependencies to latest versions

vendor/github.com/coreos/bbolt/db.go

@@ -40,6 +40,9 @@ const (
 // default page size for db is set to the OS page size.
 var defaultPageSize = os.Getpagesize()
 
+// The time elapsed between consecutive file locking attempts.
+const flockRetryTimeout = 50 * time.Millisecond
+
 // DB represents a collection of buckets persisted to a file on disk.
 // All data access is performed through transactions which can be obtained through the DB.
 // All the functions on DB will return a ErrDatabaseNotOpen if accessed before Open() is called.
@@ -113,9 +116,11 @@ type DB struct {
 	opened   bool
 	rwtx     *Tx
 	txs      []*Tx
-	freelist *freelist
 	stats    Stats
 
+	freelist     *freelist
+	freelistLoad sync.Once
+
 	pagePool sync.Pool
 
 	batchMu sync.Mutex
@@ -154,8 +159,9 @@ func (db *DB) String() string {
 // If the file does not exist then it will be created automatically.
 // Passing in nil options will cause Bolt to open the database with the default options.
 func Open(path string, mode os.FileMode, options *Options) (*DB, error) {
-	var db = &DB{opened: true}
-
+	db := &DB{
+		opened: true,
+	}
 	// Set default options if no options are provided.
 	if options == nil {
 		options = DefaultOptions
@@ -251,20 +257,11 @@ func Open(path string, mode os.FileMode, options *Options) (*DB, error) {
 		return db, nil
 	}
 
-	db.freelist = newFreelist()
-	noFreeList := db.meta().freelist == pgidNoFreelist
-	if noFreeList {
-		// Reconstruct free list by scanning the DB.
-		db.freelist.readIDs(db.freepages())
-	} else {
-		// Read free list from freelist page.
-		db.freelist.read(db.page(db.meta().freelist))
-	}
-	db.stats.FreePageN = len(db.freelist.ids)
+	db.loadFreelist()
 
 	// Flush freelist when transitioning from no sync to sync so
 	// NoFreelistSync unaware boltdb can open the db later.
-	if !db.NoFreelistSync && noFreeList {
+	if !db.NoFreelistSync && !db.hasSyncedFreelist() {
 		tx, err := db.Begin(true)
 		if tx != nil {
 			err = tx.Commit()
@@ -279,6 +276,27 @@ func Open(path string, mode os.FileMode, options *Options) (*DB, error) {
 	return db, nil
 }
 
+// loadFreelist reads the freelist if it is synced, or reconstructs it
+// by scanning the DB if it is not synced. It assumes there are no
+// concurrent accesses being made to the freelist.
+func (db *DB) loadFreelist() {
+	db.freelistLoad.Do(func() {
+		db.freelist = newFreelist()
+		if !db.hasSyncedFreelist() {
+			// Reconstruct free list by scanning the DB.
+			db.freelist.readIDs(db.freepages())
+		} else {
+			// Read free list from freelist page.
+			db.freelist.read(db.page(db.meta().freelist))
+		}
+		db.stats.FreePageN = len(db.freelist.ids)
+	})
+}
+
+func (db *DB) hasSyncedFreelist() bool {
+	return db.meta().freelist != pgidNoFreelist
+}
+
 // mmap opens the underlying memory-mapped file and initializes the meta references.
 // minsz is the minimum size that the new mmap can be.
 func (db *DB) mmap(minsz int) error {
@@ -684,11 +702,7 @@ func (db *DB) View(fn func(*Tx) error) error {
 		return err
 	}
 
-	if err := t.Rollback(); err != nil {
-		return err
-	}
-
-	return nil
+	return t.Rollback()
 }
 
 // Batch calls fn as part of a batch. It behaves similar to Update,
@@ -788,9 +802,7 @@ retry:
 
 		// pass success, or bolt internal errors, to all callers
 		for _, c := range b.calls {
-			if c.err != nil {
-				c.err <- err
-			}
+			c.err <- err
 		}
 		break retry
 	}