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// Copyright 2014 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 EXTENSIONS_BROWSER_VALUE_STORE_LEVELDB_VALUE_STORE_H_
#define EXTENSIONS_BROWSER_VALUE_STORE_LEVELDB_VALUE_STORE_H_
#include <stddef.h>
#include <string>
#include <vector>
#include "base/compiler_specific.h"
#include "base/files/file_path.h"
#include "base/macros.h"
#include "base/memory/scoped_ptr.h"
#include "base/trace_event/memory_dump_provider.h"
#include "extensions/browser/value_store/value_store.h"
#include "third_party/leveldatabase/src/include/leveldb/db.h"
namespace base {
class HistogramBase;
} // namespace base
// Value store area, backed by a leveldb database.
// All methods must be run on the FILE thread.
class LeveldbValueStore : public ValueStore,
public base::trace_event::MemoryDumpProvider {
public:
// Creates a database bound to |path|. The underlying database won't be
// opened (i.e. may not be created) until one of the get/set/etc methods are
// called - this is because opening the database may fail, and extensions
// need to be notified of that, but we don't want to permanently give up.
//
// Must be created on the FILE thread.
LeveldbValueStore(const std::string& uma_client_name,
const base::FilePath& path);
// Must be deleted on the FILE thread.
~LeveldbValueStore() override;
// ValueStore implementation.
size_t GetBytesInUse(const std::string& key) override;
size_t GetBytesInUse(const std::vector<std::string>& keys) override;
size_t GetBytesInUse() override;
ReadResult Get(const std::string& key) override;
ReadResult Get(const std::vector<std::string>& keys) override;
ReadResult Get() override;
WriteResult Set(WriteOptions options,
const std::string& key,
const base::Value& value) override;
WriteResult Set(WriteOptions options,
const base::DictionaryValue& values) override;
WriteResult Remove(const std::string& key) override;
WriteResult Remove(const std::vector<std::string>& keys) override;
WriteResult Clear() override;
// Write directly to the backing levelDB. Only used for testing to cause
// corruption in the database.
bool WriteToDbForTest(leveldb::WriteBatch* batch);
// base::trace_event::MemoryDumpProvider implementation.
bool OnMemoryDump(const base::trace_event::MemoryDumpArgs& args,
base::trace_event::ProcessMemoryDump* pmd) override;
private:
// Fix the |key| or database. If |key| is not null and the database is open
// then the key will be deleted. Otherwise the database will be repaired, and
// failing that will be deleted.
BackingStoreRestoreStatus FixCorruption(const std::string* key);
// Log, to UMA, the status of an attempt to restore a database.
BackingStoreRestoreStatus LogRestoreStatus(
BackingStoreRestoreStatus restore_status);
// Tries to open the database if it hasn't been opened already.
ValueStore::Status EnsureDbIsOpen();
// Reads a setting from the database.
ValueStore::Status ReadFromDb(const std::string& key,
// Will be reset() with the result, if any.
scoped_ptr<base::Value>* setting);
// Adds a setting to a WriteBatch, and logs the change in |changes|. For use
// with WriteToDb.
ValueStore::Status 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.
ValueStore::Status WriteToDb(leveldb::WriteBatch* batch);
// Converts an error leveldb::Status to a ValueStore::Error.
ValueStore::Status ToValueStoreError(const leveldb::Status& status);
// Delete a value (identified by |key|) from the value store.
leveldb::Status Delete(const std::string& key);
// Removes the on-disk database at |db_path_|. Any file system locks should
// be released before calling this method.
bool DeleteDbFile();
// Returns whether the database is empty.
bool IsEmpty();
// The location of the leveldb backend.
const base::FilePath db_path_;
leveldb::Options open_options_;
leveldb::ReadOptions read_options_;
// leveldb backend.
scoped_ptr<leveldb::DB> db_;
// Database is corrupt - restoration failed.
bool db_unrecoverable_;
base::HistogramBase* open_histogram_;
base::HistogramBase* db_restore_histogram_;
base::HistogramBase* value_restore_histogram_;
DISALLOW_COPY_AND_ASSIGN(LeveldbValueStore);
};
#endif // EXTENSIONS_BROWSER_VALUE_STORE_LEVELDB_VALUE_STORE_H_
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