From c1a851403d6b241bdec48685fa835c9f2cf3681b Mon Sep 17 00:00:00 2001
From: Aaron Jacobs <jacobsa@google.com>
Date: Wed, 25 Mar 2015 09:59:24 +1100
Subject: [PATCH] Added a RespondToOp helper.

---
 fuseutil/file_system.go     | 23 +++++++++++++++++++++++
 samples/hellofs/hello_fs.go | 14 +++++++-------
 2 files changed, 30 insertions(+), 7 deletions(-)

diff --git a/fuseutil/file_system.go b/fuseutil/file_system.go
index 6b65b50..fb359cb 100644
--- a/fuseutil/file_system.go
+++ b/fuseutil/file_system.go
@@ -64,6 +64,29 @@ func NewFileSystemServer(fs FileSystem) fuse.Server {
 	return fileSystemServer{fs}
 }
 
+// A convenience function that makes it easy to ensure you respond to an
+// operation when a FileSystem method returns. Responds to op with the current
+// value of *err.
+//
+// For example:
+//
+//     func (fs *myFS) ReadFile(op *fuseops.ReadFileOp) {
+//       var err error
+//       defer fuseutil.RespondToOp(op, &err)
+//
+//       if err = fs.frobnicate(); err != nil {
+//         err = fmt.Errorf("frobnicate: %v", err)
+//         return
+//       }
+//
+//       // Lots more manipulation of err, and return paths.
+//       // [...]
+//     }
+//
+func RespondToOp(op fuseops.Op, err *error) {
+	op.Respond(*err)
+}
+
 type fileSystemServer struct {
 	fs FileSystem
 }
diff --git a/samples/hellofs/hello_fs.go b/samples/hellofs/hello_fs.go
index 2957ce0..d33769c 100644
--- a/samples/hellofs/hello_fs.go
+++ b/samples/hellofs/hello_fs.go
@@ -149,14 +149,14 @@ func (fs *helloFS) patchAttributes(
 
 func (fs *helloFS) Init(op *fuseops.InitOp) {
 	var err error
-	defer func() { op.Respond(err) }()
+	defer fuseutil.RespondToOp(op, &err)
 
 	return
 }
 
 func (fs *helloFS) LookUpInode(op *fuseops.LookUpInodeOp) {
 	var err error
-	defer func() { op.Respond(err) }()
+	defer fuseutil.RespondToOp(op, &err)
 
 	// Find the info for the parent.
 	parentInfo, ok := gInodeInfo[op.Parent]
@@ -184,7 +184,7 @@ func (fs *helloFS) LookUpInode(op *fuseops.LookUpInodeOp) {
 func (fs *helloFS) GetInodeAttributes(
 	op *fuseops.GetInodeAttributesOp) {
 	var err error
-	defer func() { op.Respond(err) }()
+	defer fuseutil.RespondToOp(op, &err)
 
 	// Find the info for this inode.
 	info, ok := gInodeInfo[op.Inode]
@@ -205,7 +205,7 @@ func (fs *helloFS) GetInodeAttributes(
 func (fs *helloFS) OpenDir(
 	op *fuseops.OpenDirOp) {
 	var err error
-	defer func() { op.Respond(err) }()
+	defer fuseutil.RespondToOp(op, &err)
 
 	// Allow opening any directory.
 	return
@@ -214,7 +214,7 @@ func (fs *helloFS) OpenDir(
 func (fs *helloFS) ReadDir(
 	op *fuseops.ReadDirOp) {
 	var err error
-	defer func() { op.Respond(err) }()
+	defer fuseutil.RespondToOp(op, &err)
 
 	// Find the info for this inode.
 	info, ok := gInodeInfo[op.Inode]
@@ -253,7 +253,7 @@ func (fs *helloFS) ReadDir(
 func (fs *helloFS) OpenFile(
 	op *fuseops.OpenFileOp) {
 	var err error
-	defer func() { op.Respond(err) }()
+	defer fuseutil.RespondToOp(op, &err)
 
 	// Allow opening any file.
 	return
@@ -262,7 +262,7 @@ func (fs *helloFS) OpenFile(
 func (fs *helloFS) ReadFile(
 	op *fuseops.ReadFileOp) {
 	var err error
-	defer func() { op.Respond(err) }()
+	defer fuseutil.RespondToOp(op, &err)
 
 	// Let io.ReaderAt deal with the semantics.
 	reader := strings.NewReader("Hello, world!")