chrome/browser/chromeos/drive/file_write_watcher.h

   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 #ifndef CHROME_BROWSER_CHROMEOS_DRIVE_FILE_WRITE_WATCHER_H_
   6 #define CHROME_BROWSER_CHROMEOS_DRIVE_FILE_WRITE_WATCHER_H_
   7
   8 #include "base/callback_forward.h"
   9 #include "base/memory/scoped_ptr.h"
  10 #include "chrome/browser/chromeos/drive/file_system_util.h"
  11
  12 namespace base {
  13 class FilePath;
  14 }  // namespace base
  15
  16 namespace drive {
  17
  18 namespace internal {
  19
  20 typedef base::Callback<void(bool)> StartWatchCallback;
  21
  22 // The class watches modification to Drive files in the cache directory.
  23 // This is used for returning a local writable snapshot of Drive files from the
  24 // Save-As file dialog, so that the callers of the dialog can save to Drive
  25 // without any special handling about Drive.
  26 class FileWriteWatcher {
  27  public:
  28   FileWriteWatcher();
  29   ~FileWriteWatcher();
  30
  31   // Starts watching the modification to |path|. When it successfully started
  32   // watching, it runs |on_start_callback| by passing true as the argument.
  33   // Or if it failed, the callback is run with false.
  34   // Detected modification is notified by calling |on_write_callback|.
  35   //
  36   // Currently, the modification is watched in "one-shot" manner. That is, once
  37   // a modification is notified, the watch is deactivated for freeing system
  38   // resources. As a heuristic to capture the real end of write operations that
  39   // might be done by several chunked writes, the notification is fired after
  40   // 5 seconds has passed after the last write operation is detected.
  41   //
  42   // TODO(kinaba): investigate the possibility to continuously watch the whole
  43   // cache directory. http://crbug.com/269424
  44   void StartWatch(const base::FilePath& path,
  45                   const StartWatchCallback& on_start_callback,
  46                   const base::Closure& on_write_callback);
  47
  48   // For testing purpose, stops inserting delay between the write detection and
  49   // notification to the |on_write_callback|.
  50   void DisableDelayForTesting();
  51
  52  private:
  53   class FileWriteWatcherImpl;
  54   scoped_ptr<FileWriteWatcherImpl, util::DestroyHelper> watcher_impl_;
  55
  56   DISALLOW_COPY_AND_ASSIGN(FileWriteWatcher);
  57 };
  58
  59 }  // namespace internal
  60 }  // namespace drive
  61
  62 #endif  // CHROME_BROWSER_CHROMEOS_DRIVE_FILE_WRITE_WATCHER_H_