sync: Add interfaces for per-type sync

sync/engine/sync_directory_update_handler.h

-// Copyright 2013 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.
-
-#ifndef SYNC_ENGINE_SYNC_DIRECTORY_UPDATE_HANDLER_H_
-#define SYNC_ENGINE_SYNC_DIRECTORY_UPDATE_HANDLER_H_
-
-#include <map>
-
-#include "base/basictypes.h"
-#include "base/memory/ref_counted.h"
-#include "sync/base/sync_export.h"
-#include "sync/engine/process_updates_util.h"
-#include "sync/internal_api/public/base/model_type.h"
-#include "sync/internal_api/public/util/syncer_error.h"
-
-namespace sync_pb {
-class DataTypeProgressMarker;
-class GetUpdatesResponse;
-}
-
-namespace syncer {
-
-namespace sessions {
-class StatusController;
-}
-
-namespace syncable {
-class Directory;
-}
-
-class ModelSafeWorker;
-
-// This class represents the syncable::Directory's processes for requesting and
-// processing updates from the sync server.
-//
-// Each instance of this class represents a particular type in the
-// syncable::Directory.  It can store and retreive that type's progress markers.
-// It can also process a set of received SyncEntities and store their data.
-class SYNC_EXPORT_PRIVATE SyncDirectoryUpdateHandler {
- public:
-  SyncDirectoryUpdateHandler(syncable::Directory* dir,
-                             ModelType type,
-                             scoped_refptr<ModelSafeWorker> worker);
-  ~SyncDirectoryUpdateHandler();
-
-  // Fills the given parameter with the stored progress marker for this type.
-  void GetDownloadProgress(
-      sync_pb::DataTypeProgressMarker* progress_marker) const;
-
-  // Processes the contents of a GetUpdates response message.
-  //
-  // Should be invoked with the progress marker and set of SyncEntities from a
-  // single GetUpdates response message.  The progress marker's type must match
-  // this update handler's type, and the set of SyncEntities must include all
-  // entities of this type found in the response message.
-  void ProcessGetUpdatesResponse(
-      const sync_pb::DataTypeProgressMarker& progress_marker,
-      const SyncEntityList& applicable_updates,
-      sessions::StatusController* status);
-
-  // If there are updates to apply, apply them on the proper thread.
-  // Delegates to ApplyUpdatesImpl().
-  void ApplyUpdates(sessions::StatusController* status);
-
-  // Apply updates on the sync thread.  This is for use during initial sync
-  // prior to model association.
-  void PassiveApplyUpdates(sessions::StatusController* status);
-
- private:
-  friend class SyncDirectoryUpdateHandlerApplyUpdateTest;
-  friend class SyncDirectoryUpdateHandlerProcessUpdateTest;
-
-  // Sometimes there is nothing to do, so we can return without doing anything.
-  bool IsApplyUpdatesRequired();
-
-  // Processes the given SyncEntities and stores their data in the directory.
-  // Their types must match this update handler's type.
-  void UpdateSyncEntities(
-      syncable::ModelNeutralWriteTransaction* trans,
-      const SyncEntityList& applicable_updates,
-      sessions::StatusController* status);
-
-  // Stores the given progress marker in the directory.
-  // Its type must match this update handler's type.
-  void UpdateProgressMarker(
-      const sync_pb::DataTypeProgressMarker& progress_marker);
-
-  // Skips all checks and goes straight to applying the updates.
-  SyncerError ApplyUpdatesImpl(sessions::StatusController* status);
-
-  syncable::Directory* dir_;
-  ModelType type_;
-  scoped_refptr<ModelSafeWorker> worker_;
-
-  DISALLOW_COPY_AND_ASSIGN(SyncDirectoryUpdateHandler);
-};
-
-}  // namespace syncer
-
-#endif  // SYNC_ENGINE_SYNC_DIRECTORY_UPDATE_HANDLER_H_