Declared NotImplementedFileSystem.

fuseutil/file_system.go

@@ -26,6 +26,9 @@ import (
 //
 // Each method should fill in appropriate response fields for the supplied op
 // and return an error status, but not call Repand.
+//
+// See NotImplementedFileSystem for a convenient way to embed default
+// implementations for methods you don't care about.
 type FileSystem interface {
 	Init(*fuseops.InitOp) error
 	LookUpInode(*fuseops.LookUpInodeOp) error

fuseutil/not_implemented_file_system.go

@@ -0,0 +1,24 @@
+// Copyright 2015 Google Inc. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package fuseutil
+
+// A FileSystem that returns ENOSYS for all methods. Embed this in your struct
+// to inherit default implementations for the methods you don't care about,
+// ensuring your struct will continue to implement FileSystem even as new
+// methods are added.
+type NotImplementedFileSystem struct {
+}
+
+var _ FileSystem = &NotImplementedFileSystem{}