1// Copyright 2013 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#include "chrome/browser/media_galleries/fileapi/file_path_watcher_util.h"
6
7#include "base/bind.h"
8#include "base/callback.h"
9#include "base/location.h"
10#include "base/logging.h"
11#include "chrome/browser/media_galleries/fileapi/media_file_system_backend.h"
12#include "content/public/browser/browser_thread.h"
13
14namespace {
15
16// Bounces |path| and |error| to |callback| from the FILE thread to the media
17// task runner.
18void OnFilePathChangedOnFileThread(
19    const base::FilePathWatcher::Callback& callback,
20    const base::FilePath& path,
21    bool error) {
22  DCHECK_CURRENTLY_ON(content::BrowserThread::FILE);
23  MediaFileSystemBackend::MediaTaskRunner()->PostTask(
24      FROM_HERE, base::Bind(callback, path, error));
25}
26
27// The watch has to be started on the FILE thread, and the callback called by
28// the FilePathWatcher also needs to run on the FILE thread.
29void StartFilePathWatchOnFileThread(
30    const base::FilePath& path,
31    const FileWatchStartedCallback& watch_started_callback,
32    const base::FilePathWatcher::Callback& path_changed_callback) {
33  DCHECK_CURRENTLY_ON(content::BrowserThread::FILE);
34  // The watcher is created on the FILE thread because it is very difficult
35  // to safely pass an already-created file watcher to a different thread.
36  scoped_ptr<base::FilePathWatcher> watcher(new base::FilePathWatcher);
37  bool success = watcher->Watch(
38      path,
39      false /* recursive */,
40      base::Bind(&OnFilePathChangedOnFileThread, path_changed_callback));
41  if (!success)
42    LOG(ERROR) << "Adding watch for " << path.value() << " failed";
43  MediaFileSystemBackend::MediaTaskRunner()->PostTask(
44      FROM_HERE, base::Bind(watch_started_callback, base::Passed(&watcher)));
45}
46
47}  // namespace
48
49void StartFilePathWatchOnMediaTaskRunner(
50    const base::FilePath& path,
51    const FileWatchStartedCallback& watch_started_callback,
52    const base::FilePathWatcher::Callback& path_changed_callback) {
53  DCHECK(MediaFileSystemBackend::CurrentlyOnMediaTaskRunnerThread());
54  content::BrowserThread::PostTask(content::BrowserThread::FILE,
55                                   FROM_HERE,
56                                   base::Bind(&StartFilePathWatchOnFileThread,
57                                              path,
58                                              watch_started_callback,
59                                              path_changed_callback));
60}
61