blob: 7ad2cccebe9ef0cc8ac73c2f0af744c67a4bf5ee [file] [log] [blame]
// Copyright 2015 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_API_MODEL_TYPE_SERVICE_H_
#define SYNC_API_MODEL_TYPE_SERVICE_H_
#include <memory>
#include <string>
#include <vector>
#include "base/callback.h"
#include "sync/api/conflict_resolution.h"
#include "sync/api/entity_change.h"
#include "sync/api/entity_data.h"
#include "sync/api/model_type_change_processor.h"
#include "sync/api/sync_error.h"
#include "sync/base/sync_export.h"
#include "sync/internal_api/public/activation_context.h"
namespace syncer_v2 {
class DataBatch;
class MetadataChangeList;
// Interface implemented by model types to receive updates from sync via the
// SharedModelTypeProcessor. Provides a way for sync to update the data and
// metadata for entities, as well as the model type state.
class SYNC_EXPORT ModelTypeService {
public:
typedef base::Callback<void(syncer::SyncError, std::unique_ptr<DataBatch>)>
DataCallback;
typedef std::vector<std::string> ClientTagList;
typedef base::Callback<std::unique_ptr<ModelTypeChangeProcessor>(
syncer::ModelType type,
ModelTypeService* service)>
ChangeProcessorFactory;
ModelTypeService(const ChangeProcessorFactory& change_processor_factory,
syncer::ModelType type);
virtual ~ModelTypeService();
// Creates an object used to communicate changes in the sync metadata to the
// model type store.
virtual std::unique_ptr<MetadataChangeList> CreateMetadataChangeList() = 0;
// Perform the initial merge between local and sync data. This should only be
// called when a data type is first enabled to start syncing, and there is no
// sync metadata. Best effort should be made to match local and sync data. The
// keys in the |entity_data_map| will have been created via GetClientTag(...),
// and if a local and sync data should match/merge but disagree on tags, the
// service should use the sync data's tag. Any local pieces of data that are
// not present in sync should immediately be Put(...) to the processor before
// returning. The same MetadataChangeList that was passed into this function
// can be passed to Put(...) calls. Delete(...) can also be called but should
// not be needed for most model types. Durable storage writes, if not able to
// combine all change atomically, should save the metadata after the data
// changes, so that this merge will be re-driven by sync if is not completely
// saved during the current run.
virtual syncer::SyncError MergeSyncData(
std::unique_ptr<MetadataChangeList> metadata_change_list,
EntityDataMap entity_data_map) = 0;
// Apply changes from the sync server locally.
// Please note that |entity_changes| might have fewer entries than
// |metadata_change_list| in case when some of the data changes are filtered
// out, or even be empty in case when a commit confirmation is processed and
// only the metadata needs to persisted.
virtual syncer::SyncError ApplySyncChanges(
std::unique_ptr<MetadataChangeList> metadata_change_list,
EntityChangeList entity_changes) = 0;
// Asynchronously retrieve the corresponding sync data for |client_tags|.
virtual void GetData(ClientTagList client_tags, DataCallback callback) = 0;
// Asynchronously retrieve all of the local sync data.
virtual void GetAllData(DataCallback callback) = 0;
// Get or generate a client tag for |entity_data|.
virtual std::string GetClientTag(const EntityData& entity_data) = 0;
// Overridable notification for when the processor is set. This is typically
// when the service should start loading metadata and then subsequently giving
// it to the processor.
virtual void OnChangeProcessorSet() = 0;
// Resolve a conflict between the client and server versions of data. They are
// guaranteed not to match (both be deleted or have identical specifics). A
// default implementation chooses the server data unless it is a deletion.
virtual ConflictResolution ResolveConflict(
const EntityData& local_data,
const EntityData& remote_data) const;
void clear_change_processor();
void OnSyncStarting(const ModelTypeChangeProcessor::StartCallback& callback);
protected:
// TODO(skym): See crbug/547087, do we need all these accessors?
ModelTypeChangeProcessor* change_processor() const;
ModelTypeChangeProcessor* GetOrCreateChangeProcessor();
// Model type for this service.
syncer::ModelType type() const;
private:
std::unique_ptr<ModelTypeChangeProcessor> change_processor_;
ChangeProcessorFactory change_processor_factory_;
const syncer::ModelType type_;
};
} // namespace syncer_v2
#endif // SYNC_API_MODEL_TYPE_SERVICE_H_