data_type_store.h | Explore in Territory

// Copyright 2015 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef COMPONENTS_SYNC_MODEL_DATA_TYPE_STORE_H_
#define COMPONENTS_SYNC_MODEL_DATA_TYPE_STORE_H_

#include <memory>
#include <optional>

#include "base/functional/callback.h"
#include "components/sync/base/data_type.h"
#include "components/sync/model/data_type_store_base.h"
#include "components/sync/model/model_error.h"

namespace syncer {

class MetadataBatch;

// DataTypeStore is leveldb backed store for data type's data, metadata and
// global metadata.
//
// Store keeps records for entries identified by ids. For each entry store keeps
// data and metadata. Also store keeps one record for global metadata.
//
// To create store call one of Create*Store static factory functions. Data type
// controls store's lifetime with returned unique_ptr. Call to Create*Store
// function triggers asynchronous store backend initialization, callback will be
// called with results when initialization is done.
//
// Read operations are asynchronous, initiated with one of Read* functions,
// provided callback will be called with result code and output of read
// operation.
//
// Write operations are done in context of write batch. To get one call
// CreateWriteBatch(). After that pass write batch object to Write/Delete
// functions. WriteBatch only accumulates pending changes, doesn't actually do
// data modification. Calling CommitWriteBatch writes all accumulated changes to
// disk atomically. Callback passed to CommitWriteBatch will be called with
// result of write operation. If write batch object is destroyed without
// comitting accumulated write operations will not be persisted.
//
// Destroying store object doesn't necessarily cancel asynchronous operations
// issued previously. You should be prepared to handle callbacks from those
// operations.
class DataTypeStore : public DataTypeStoreBase { … };

// Typedef for a store factory that has all params bound except InitCallback.
RepeatingDataTypeStoreFactory;

// Same as above but as a OnceCallback.
OnceDataTypeStoreFactory;

}  // namespace syncer

#endif  // COMPONENTS_SYNC_MODEL_DATA_TYPE_STORE_H_
chromium/components/sync/model/data_type_store.h
