1 // Copyright (c) 2006-2009 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_SYNC_ENGINE_DOWNLOAD_UPDATES_COMMAND_H_ 6 #define CHROME_BROWSER_SYNC_ENGINE_DOWNLOAD_UPDATES_COMMAND_H_ 7 #pragma once 8 9 #include "base/basictypes.h" 10 #include "chrome/browser/sync/engine/model_safe_worker.h" 11 #include "chrome/browser/sync/engine/syncer_command.h" 12 #include "chrome/browser/sync/syncable/model_type.h" 13 14 namespace sync_pb { 15 class EntitySpecifics; 16 } 17 18 namespace browser_sync { 19 20 // Determine the enabled datatypes, download a batch of updates for them 21 // from the server, place the result in the SyncSession for further processing. 22 // 23 // The main inputs to this operation are the download_progress state 24 // in the syncable::Directory, and the set of enabled types as indicated by 25 // the SyncSession. DownloadUpdatesCommand will fetch updates for 26 // all the enabled types, using download_progress to indicate the starting 27 // point to the server. DownloadUpdatesCommand stores the server response 28 // in the SyncSession. Only one server request is performed per Execute 29 // operation. A loop that causes multiple Execute operations within a sync 30 // session can be found in the Syncer logic. When looping, the 31 // DownloadUpdatesCommand consumes the information stored by the 32 // StoreTimestampsCommand. 33 // 34 // In practice, DownloadUpdatesCommand should loop until all updates are 35 // downloaded for all enabled datatypes (i.e., until the server indicates 36 // changes_remaining == 0 in the GetUpdates response), or until an error 37 // is encountered. 38 class DownloadUpdatesCommand : public SyncerCommand { 39 public: 40 DownloadUpdatesCommand(); 41 virtual ~DownloadUpdatesCommand(); 42 43 // SyncerCommand implementation. 44 virtual void ExecuteImpl(sessions::SyncSession* session); 45 46 void SetRequestedTypes(const syncable::ModelTypeBitSet& target_datatypes, 47 sync_pb::EntitySpecifics* filter_protobuf); 48 49 private: 50 DISALLOW_COPY_AND_ASSIGN(DownloadUpdatesCommand); 51 }; 52 53 } // namespace browser_sync 54 55 #endif // CHROME_BROWSER_SYNC_ENGINE_DOWNLOAD_UPDATES_COMMAND_H_ 56 57