Provide easier way for locking file storage

cmd/tusd/main.go

@@ -44,9 +44,7 @@ func main() {
 	}
 
 	var store tusd.DataStore
-	store = filestore.FileStore{
+	store = filestore.New(dir)
-		Path: dir,
-	}
 
 	if storeSize > 0 {
 		store = limitedstore.New(storeSize, store)

filestore/filestore.go

@@ -15,6 +15,7 @@ import (
 	"os"
 
 	"github.com/tus/tusd"
+	"github.com/tus/tusd/lockingstore"
 	"github.com/tus/tusd/uid"
 )
 
@@ -24,10 +25,25 @@ var defaultFilePerm = os.FileMode(0775)
 // methods.
 type FileStore struct {
 	// Relative or absolute path to store files in. FileStore does not check
-	// whether the path exists, you os.MkdirAll in this case on your own.
+	// whether the path exists, use os.MkdirAll in this case on your own.
 	Path string
 }
 
+// New creates a new file based storage backend. The directory specified will
+// be used as the only storage entry. This method does not check
+// whether the path exists, use os.MkdirAll to ensure.
+// In addition, a locking mechanism is provided using lockingstore.LockingStore
+// and FileLocker.
+func New(path string) tusd.DataStore {
+	store := FileStore{path}
+	locker := FileLocker{path}
+
+	return lockingstore.LockingStore{
+		DataStore: &store,
+		Locker:    &locker,
+	}
+}
+
 func (store FileStore) NewUpload(info tusd.FileInfo) (id string, err error) {
 	id = uid.Uid()
 	info.ID = id