| // Copyright (c) 2010 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| // This module provides a way to monitor a file for changes. |
| |
| #ifndef CHROME_BROWSER_FILE_WATCHER_H_ |
| #define CHROME_BROWSER_FILE_WATCHER_H_ |
| |
| #include "base/basictypes.h" |
| #include "base/ref_counted.h" |
| #include "chrome/browser/chrome_thread.h" |
| |
| class FilePath; |
| // This class lets you register interest in changes on a file. The delegate |
| // will get called whenever the file is changed, including created or deleted. |
| // WARNING: To be able to get create/delete notifications and to work cross |
| // platform, we actually listen for changes to the directory containing |
| // the file. |
| // WARNING: On OSX and Windows, the OS API doesn't tell us which file in the |
| // directory changed. We work around this by watching the file time, but this |
| // can result in some extra notifications if we get other notifications within |
| // 2s of the file having changed. |
| class FileWatcher { |
| public: |
| class Delegate { |
| public: |
| virtual ~Delegate() {} |
| virtual void OnFileChanged(const FilePath& path) = 0; |
| }; |
| |
| FileWatcher(); |
| ~FileWatcher() {} |
| |
| // Register interest in any changes on the file |path|. |
| // OnFileChanged will be called back for each change to the file. Any |
| // background operations will be ran on |backend_thread_id|. Note: The |
| // directory containing |path| must exist before you try to watch the file. |
| // Returns false if the watch can't be added. |
| bool Watch(const FilePath& path, Delegate* delegate) { |
| DCHECK(ChromeThread::CurrentlyOn(ChromeThread::FILE)); |
| return impl_->Watch(path, delegate); |
| } |
| |
| // Used internally to encapsulate different members on different platforms. |
| class PlatformDelegate |
| : public base::RefCountedThreadSafe<PlatformDelegate, |
| ChromeThread::DeleteOnFileThread> { |
| public: |
| virtual ~PlatformDelegate() {} |
| |
| virtual bool Watch(const FilePath& path, Delegate* delegate) = 0; |
| }; |
| |
| private: |
| scoped_refptr<PlatformDelegate> impl_; |
| |
| DISALLOW_COPY_AND_ASSIGN(FileWatcher); |
| }; |
| |
| #endif // CHROME_BROWSER_FILE_WATCHER_H_ |