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// 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_INTERNAL_API_PUBLIC_MODEL_TYPE_STORE_BACKEND_H_
#define SYNC_INTERNAL_API_PUBLIC_MODEL_TYPE_STORE_BACKEND_H_
#include <string>
#include "base/macros.h"
#include "base/memory/scoped_ptr.h"
#include "base/threading/non_thread_safe.h"
#include "sync/api/model_type_store.h"
#include "sync/base/sync_export.h"
namespace leveldb {
class DB;
class Env;
class WriteBatch;
} // namespace leveldb
namespace syncer_v2 {
// ModelTypeStoreBackend handles operations with leveldb. It is oblivious of the
// fact that it is called from separate thread (with the exception of ctor),
// meaning it shouldn't deal with callbacks and task_runners.
class SYNC_EXPORT_PRIVATE ModelTypeStoreBackend : public base::NonThreadSafe {
public:
ModelTypeStoreBackend();
~ModelTypeStoreBackend();
// Helper function to create in memory environment for leveldb.
static scoped_ptr<leveldb::Env> CreateInMemoryEnv();
// Take ownership of env from consumer of ModelTypeStoreBackend object. env
// will be deleted right after db_ is deleted. This function allows tests to
// create in-memory store without requiring them to manage env ownership.
void TakeEnvOwnership(scoped_ptr<leveldb::Env> env);
// Init opens database at |path|. If database doesn't exist it creates one.
// Normally |env| should be nullptr, this causes leveldb to use default disk
// based environment from leveldb::Env::Default().
// Providing |env| allows to override environment used by leveldb for tests
// with in-memory or faulty environment.
ModelTypeStore::Result Init(const std::string& path, leveldb::Env* env);
// Reads records with keys formed by prepending ids from |id_list| with
// |prefix|. If the record is found its id (without prefix) and value is
// appended to record_list. If record is not found its id is appended to
// |missing_id_list|. It is not an error that records for ids are not found so
// function will still return success in this case.
ModelTypeStore::Result ReadRecordsWithPrefix(
const std::string& prefix,
const ModelTypeStore::IdList& id_list,
ModelTypeStore::RecordList* record_list,
ModelTypeStore::IdList* missing_id_list);
// Reads all records with keys starting with |prefix|. Prefix is removed from
// key before it is added to |record_list|.
ModelTypeStore::Result ReadAllRecordsWithPrefix(
const std::string& prefix,
ModelTypeStore::RecordList* record_list);
// Writes modifications accumulated in |write_batch| to database.
ModelTypeStore::Result WriteModifications(
scoped_ptr<leveldb::WriteBatch> write_batch);
private:
// In some scenarios ModelTypeStoreBackend holds ownership of env. Typical
// example is when test creates in memory environment with CreateInMemoryEnv
// and wants it to be destroyed along with backend. This is achieved by
// passing ownership of env to TakeEnvOwnership function.
//
// env_ declaration should appear before declaration of db_ because
// environment object should still be valid when db_'s destructor is called.
scoped_ptr<leveldb::Env> env_;
scoped_ptr<leveldb::DB> db_;
DISALLOW_COPY_AND_ASSIGN(ModelTypeStoreBackend);
};
} // namespace syncer_v2
#endif // SYNC_INTERNAL_API_PUBLIC_MODEL_TYPE_STORE_BACKEND_H_
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