Added a FileSystem interface and declared a function that transforms it.

fuseutil/file_system.go

+// 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
+
+import (
+	"github.com/jacobsa/fuse"
+	"github.com/jacobsa/fuse/fuseops"
+)
+
+// An interface with a method for each op type in the fuseops package. This can
+// be used in conjunction with NewFileSystemServer to avoid writing a "dispatch
+// loop" that switches on op types, instead receiving typed method calls
+// directly.
+//
+// Each method should fill in appropriate response fields for the supplied op
+// and return an error status, but not call Repand.
+type FileSystem interface {
+	Init(*fuseops.InitOp) error
+	LookUpInode(*fuseops.LookUpInodeOp) error
+	GetInodeAttributes(*fuseops.GetInodeAttributesOp) error
+	SetInodeAttributes(*fuseops.SetInodeAttributesOp) error
+	ForgetInode(*fuseops.ForgetInodeOp) error
+	MkDir(*fuseops.MkDirOp) error
+	CreateFile(*fuseops.CreateFileOp) error
+	RmDir(*fuseops.RmDirOp) error
+	Unlink(*fuseops.UnlinkOp) error
+	OpenDir(*fuseops.OpenDirOp) error
+	ReadDir(*fuseops.ReadDirOp) error
+	ReleaseDirHandle(*fuseops.ReleaseDirHandleOp) error
+	OpenFile(*fuseops.OpenFileOp) error
+	ReadFile(*fuseops.ReadFileOp) error
+	WriteFile(*fuseops.WriteFileOp) error
+	SyncFile(*fuseops.SyncFileOp) error
+	FlushFile(*fuseops.FlushFileOp) error
+	ReleaseFileHandle(*fuseops.ReleaseFileHandleOp) error
+}
+
+// Create a fuse.Server that serves ops by calling the associated FileSystem
+// method and then calling Op.Respond with the resulting error. Unsupported ops
+// are responded to directly with ENOSYS.
+func NewFileSystemServer(fs FileSystem) fuse.Server