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// Copyright (c) 2012 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 CHROME_BROWSER_VALUE_STORE_LEVELDB_VALUE_STORE_H_
#define CHROME_BROWSER_VALUE_STORE_LEVELDB_VALUE_STORE_H_
#include <string>
#include <vector>
#include "base/compiler_specific.h"
#include "base/file_path.h"
#include "base/memory/scoped_ptr.h"
#include "chrome/browser/value_store/value_store.h"
#include "third_party/leveldatabase/src/include/leveldb/db.h"
// Value store area, backed by a leveldb database.
// All methods must be run on the FILE thread.
class LeveldbValueStore : public ValueStore {
public:
// Must be deleted on the FILE thread.
virtual ~LeveldbValueStore();
// Create and open the database at the given path.
static LeveldbValueStore* Create(const FilePath& path);
// ValueStore implementation.
virtual size_t GetBytesInUse(const std::string& key) OVERRIDE;
virtual size_t GetBytesInUse(const std::vector<std::string>& keys) OVERRIDE;
virtual size_t GetBytesInUse() OVERRIDE;
virtual ReadResult Get(const std::string& key) OVERRIDE;
virtual ReadResult Get(const std::vector<std::string>& keys) OVERRIDE;
virtual ReadResult Get() OVERRIDE;
virtual WriteResult Set(
WriteOptions options,
const std::string& key,
const Value& value) OVERRIDE;
virtual WriteResult Set(
WriteOptions options, const DictionaryValue& values) OVERRIDE;
virtual WriteResult Remove(const std::string& key) OVERRIDE;
virtual WriteResult Remove(const std::vector<std::string>& keys) OVERRIDE;
virtual WriteResult Clear() OVERRIDE;
private:
// Ownership of db is taken.
LeveldbValueStore(const FilePath& db_path, leveldb::DB* db);
// Reads a setting from the database. Returns the error message on failure,
// or "" on success in which case |setting| will be reset to the Value read
// from the database. This value may be NULL.
std::string ReadFromDb(
leveldb::ReadOptions options,
const std::string& key,
// Will be reset() with the result, if any.
scoped_ptr<Value>* setting);
// Adds a setting to a WriteBatch, and logs the change in |changes|. For use
// with WriteToDb. Returns the error message on failure, or "" on success.
std::string AddToBatch(
ValueStore::WriteOptions options,
const std::string& key,
const base::Value& value,
leveldb::WriteBatch* batch,
ValueStoreChangeList* changes);
// Commits the changes in |batch| to the database, returning the error message
// on failure or "" on success.
std::string WriteToDb(leveldb::WriteBatch* batch);
// Returns whether the database is empty.
bool IsEmpty();
// The location of the leveldb backend.
const FilePath db_path_;
// leveldb backend.
scoped_ptr<leveldb::DB> db_;
DISALLOW_COPY_AND_ASSIGN(LeveldbValueStore);
};
#endif // CHROME_BROWSER_VALUE_STORE_LEVELDB_VALUE_STORE_H_
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