backend/layout: Add Basedir()

src/restic/backend/layout.go

@@ -15,6 +15,7 @@ import (
 type Layout interface {
 	Filename(restic.Handle) string
 	Dirname(restic.Handle) string
+	Basedir(restic.FileType) string
 	Paths() []string
 }
 

src/restic/backend/layout_cloud.go

@@ -34,3 +34,8 @@ func (l *CloudLayout) Paths() (dirs []string) {
 	}
 	return dirs
 }
+
+// Basedir returns the base dir name for files of type t.
+func (l *CloudLayout) Basedir(t restic.FileType) string {
+	return l.Join(l.Path, cloudLayoutPaths[t])
+}

src/restic/backend/layout_default.go

@@ -47,3 +47,8 @@ func (l *DefaultLayout) Paths() (dirs []string) {
 	}
 	return dirs
 }
+
+// Basedir returns the base dir name for type t.
+func (l *DefaultLayout) Basedir(t restic.FileType) string {
+	return l.Join(l.Path, defaultLayoutPaths[t])
+}

src/restic/backend/layout_s3.go

@@ -40,3 +40,8 @@ func (l *S3Layout) Paths() (dirs []string) {
 	}
 	return dirs
 }
+
+// Basedir returns the base dir name for type t.
+func (l *S3Layout) Basedir(t restic.FileType) string {
+	return l.Join(l.Path, s3LayoutPaths[t])
+}