local: Automatically detect layout

src/restic/backend/local/local.go

@@ -22,9 +22,12 @@ type Local struct {
 // ensure statically that *Local implements restic.Backend.
 var _ restic.Backend = &Local{}
 
+const defaultLayout = "default"
+
 // Open opens the local backend as specified by config.
 func Open(cfg Config) (*Local, error) {
-	l, err := backend.ParseLayout(nil, cfg.Layout, cfg.Path)
+	debug.Log("open local backend at %v (layout %q)", cfg.Path, cfg.Layout)
+	l, err := backend.ParseLayout(&backend.LocalFilesystem{}, cfg.Layout, defaultLayout, cfg.Path)
 	if err != nil {
 		return nil, err
 	}
@@ -44,16 +47,20 @@ func Open(cfg Config) (*Local, error) {
 // Create creates all the necessary files and directories for a new local
 // backend at dir. Afterwards a new config blob should be created.
 func Create(cfg Config) (*Local, error) {
+	debug.Log("create local backend at %v (layout %q)", cfg.Path, cfg.Layout)
+
+	l, err := backend.ParseLayout(&backend.LocalFilesystem{}, cfg.Layout, defaultLayout, cfg.Path)
+	if err != nil {
+		return nil, err
+	}
+
 	be := &Local{
 		Config: cfg,
-		Layout: &backend.DefaultLayout{
-			Path: cfg.Path,
-			Join: filepath.Join,
-		},
+		Layout: l,
 	}
 
 	// test if config file already exists
-	_, err := fs.Lstat(be.Filename(restic.Handle{Type: restic.ConfigFile}))
+	_, err = fs.Lstat(be.Filename(restic.Handle{Type: restic.ConfigFile}))
 	if err == nil {
 		return nil, errors.New("config file already exists")
 	}