add samples/mount_hello executable

This is a simple program to verify that the FUSE library itself works,
easier to run than the existing samples/mount with flushfs.

samples/mount_hello/mount.go

@@ -0,0 +1,68 @@
+// 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.
+
+// A simple tool for mounting sample file systems, used by the tests in
+// samples/.
+package main
+
+import (
+	"context"
+	"flag"
+	"log"
+	"os"
+
+	"github.com/jacobsa/fuse"
+	"github.com/jacobsa/fuse/samples/hellofs"
+	"github.com/jacobsa/timeutil"
+)
+
+var fType = flag.String("type", "", "The name of the samples/ sub-dir.")
+var fMountPoint = flag.String("mount_point", "", "Path to mount point.")
+var fReadyFile = flag.Uint64("ready_file", 0, "FD to signal when ready.")
+
+var fReadOnly = flag.Bool("read_only", false, "Mount in read-only mode.")
+var fDebug = flag.Bool("debug", false, "Enable debug logging.")
+
+func main() {
+	flag.Parse()
+
+	// Create an appropriate file system.
+	server, err := hellofs.NewHelloFS(timeutil.RealClock())
+	if err != nil {
+		log.Fatalf("makeFS: %v", err)
+	}
+
+	// Mount the file system.
+	if *fMountPoint == "" {
+		log.Fatalf("You must set --mount_point.")
+	}
+
+	cfg := &fuse.MountConfig{
+		ReadOnly: *fReadOnly,
+	}
+
+	if *fDebug {
+		cfg.DebugLogger = log.New(os.Stderr, "fuse: ", 0)
+	}
+
+	mfs, err := fuse.Mount(*fMountPoint, server, cfg)
+	if err != nil {
+		log.Fatalf("Mount: %v", err)
+	}
+
+	// Wait for it to be unmounted.
+	if err = mfs.Join(context.Background()); err != nil {
+		log.Fatalf("Join: %v", err)
+	}
+}