storage/browser/fileapi/watcher_manager.h

   1 // Copyright 2014 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 STORAGE_BROWSER_FILEAPI_WATCHER_MANAGER_H_
   6 #define STORAGE_BROWSER_FILEAPI_WATCHER_MANAGER_H_
   7
   8 #include <vector>
   9
  10 #include "base/basictypes.h"
  11 #include "base/callback_forward.h"
  12 #include "base/files/file.h"
  13
  14 namespace storage {
  15
  16 class FileSystemOperationContext;
  17 class FileSystemURL;
  18
  19 // An interface for providing entry observing capability for file system
  20 // backends.
  21 //
  22 // It is NOT valid to give null callback to this class, and implementors
  23 // can assume that they don't get any null callbacks.
  24 class WatcherManager {
  25  public:
  26   enum ChangeType { CHANGED, DELETED };
  27
  28   typedef base::Callback<void(base::File::Error result)> StatusCallback;
  29   typedef base::Callback<void(ChangeType change_type)> NotificationCallback;
  30
  31   virtual ~WatcherManager() {}
  32
  33   // Adds an entry watcher. If the |recursive| mode is not supported then
  34   // FILE_ERROR_INVALID_OPERATION must be returned as an error. If the |url| is
  35   // already watched with the same |recursive|, or setting up the watcher fails,
  36   // then |callback| must be called with a specific error code.
  37   //
  38   // There may be up to two watchers for the same |url| as well as one of them
  39   // is recursive, and the other one is not.
  40   //
  41   // In case of a success |callback| must be called with the FILE_OK error code.
  42   // |notification_callback| is called for every change related to the watched
  43   // directory.
  44   virtual void AddWatcher(
  45       const FileSystemURL& url,
  46       bool recursive,
  47       const StatusCallback& callback,
  48       const NotificationCallback& notification_callback) = 0;
  49
  50   // Removes a watcher represented by |url| in |recursive| mode.
  51   virtual void RemoveWatcher(const FileSystemURL& url,
  52                              bool recursive,
  53                              const StatusCallback& callback) = 0;
  54 };
  55
  56 }  // namespace storage
  57
  58 #endif  // STORAGE_BROWSER_FILEAPI_WATCHER_MANAGER_H_