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 14namespace sync_pb { 15class EntitySpecifics; 16} 17 18namespace 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. 38class 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