fix putMany error handling and types

1. Use []byte instead of interface{}.
2. Handle rename errors.
3. Correctly temporary files.

flatfs.go

@@ -476,7 +476,7 @@ func (fs *Datastore) doPut(key datastore.Key, val []byte) error {
 	return nil
 }
 
-func (fs *Datastore) putMany(data map[datastore.Key]interface{}) error {
+func (fs *Datastore) putMany(data map[datastore.Key][]byte) error {
 	fs.shutdownLock.RLock()
 	defer fs.shutdownLock.RUnlock()
 	if fs.shutdown {
@@ -484,13 +484,24 @@ func (fs *Datastore) putMany(data map[datastore.Key]interface{}) error {
 	}
 
 	var dirsToSync []string
-	files := make(map[*os.File]*op)
 
-	for key, value := range data {
-		val, ok := value.([]byte)
-		if !ok {
-			return datastore.ErrInvalidType
+	files := make(map[*os.File]*op, len(data))
+	ops := make(map[*os.File]int, len(data))
+
+	defer func() {
+		for fi := range files {
+			val, _ := ops[fi]
+			switch val {
+			case 0:
+				_ = fi.Close()
+				fallthrough
+			case 1:
+				_ = os.Remove(fi.Name())
+			}
 		}
+	}()
+
+	for key, value := range data {
 		dir, path := fs.encode(key)
 		if err := fs.makeDirNoSync(dir); err != nil {
 			return err
@@ -502,7 +513,7 @@ func (fs *Datastore) putMany(data map[datastore.Key]interface{}) error {
 			return err
 		}
 
-		if _, err := tmp.Write(val); err != nil {
+		if _, err := tmp.Write(value); err != nil {
 			return err
 		}
 
@@ -514,24 +525,9 @@ func (fs *Datastore) putMany(data map[datastore.Key]interface{}) error {
 		}
 	}
 
-	ops := make(map[*os.File]int)
-
-	defer func() {
-		for fi, _ := range files {
-			val, _ := ops[fi]
-			switch val {
-			case 0:
-				_ = fi.Close()
-				fallthrough
-			case 1:
-				_ = os.Remove(fi.Name())
-			}
-		}
-	}()
-
 	// Now we sync everything
 	// sync and close files
-	for fi, _ := range files {
+	for fi := range files {
 		if fs.sync {
 			if err := syncFile(fi); err != nil {
 				return err
@@ -548,7 +544,10 @@ func (fs *Datastore) putMany(data map[datastore.Key]interface{}) error {
 
 	// move files to their proper places
 	for fi, op := range files {
-		fs.doWriteOp(op)
+		err := fs.doWriteOp(op)
+		if err != nil {
+			return err
+		}
 		// signify removed
 		ops[fi] = 2
 	}
@@ -1063,7 +1062,7 @@ func (fs *Datastore) Close() error {
 }
 
 type flatfsBatch struct {
-	puts    map[datastore.Key]interface{}
+	puts    map[datastore.Key][]byte
 	deletes map[datastore.Key]struct{}
 
 	ds *Datastore
@@ -1071,7 +1070,7 @@ type flatfsBatch struct {
 
 func (fs *Datastore) Batch() (datastore.Batch, error) {
 	return &flatfsBatch{
-		puts:    make(map[datastore.Key]interface{}),
+		puts:    make(map[datastore.Key][]byte),
 		deletes: make(map[datastore.Key]struct{}),
 		ds:      fs,
 	}, nil