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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 BASE_PREFS_JSON_PREF_STORE_H_
#define BASE_PREFS_JSON_PREF_STORE_H_
#include <set>
#include <string>
#include "base/basictypes.h"
#include "base/compiler_specific.h"
#include "base/files/file_path.h"
#include "base/files/important_file_writer.h"
#include "base/memory/scoped_ptr.h"
#include "base/message_loop/message_loop_proxy.h"
#include "base/observer_list.h"
#include "base/prefs/base_prefs_export.h"
#include "base/prefs/persistent_pref_store.h"
namespace base {
class DictionaryValue;
class FilePath;
class SequencedTaskRunner;
class SequencedWorkerPool;
class Value;
}
// A writable PrefStore implementation that is used for user preferences.
class BASE_PREFS_EXPORT JsonPrefStore
: public PersistentPrefStore,
public base::ImportantFileWriter::DataSerializer {
public:
// Returns instance of SequencedTaskRunner which guarantees that file
// operations on the same file will be executed in sequenced order.
static scoped_refptr<base::SequencedTaskRunner> GetTaskRunnerForFile(
const base::FilePath& pref_filename,
base::SequencedWorkerPool* worker_pool);
// |sequenced_task_runner| is must be a shutdown-blocking task runner, ideally
// created by GetTaskRunnerForFile() method above.
JsonPrefStore(const base::FilePath& pref_filename,
base::SequencedTaskRunner* sequenced_task_runner);
// PrefStore overrides:
virtual bool GetValue(const std::string& key,
const base::Value** result) const OVERRIDE;
virtual void AddObserver(PrefStore::Observer* observer) OVERRIDE;
virtual void RemoveObserver(PrefStore::Observer* observer) OVERRIDE;
virtual bool HasObservers() const OVERRIDE;
virtual bool IsInitializationComplete() const OVERRIDE;
// PersistentPrefStore overrides:
virtual bool GetMutableValue(const std::string& key,
base::Value** result) OVERRIDE;
virtual void SetValue(const std::string& key, base::Value* value) OVERRIDE;
virtual void SetValueSilently(const std::string& key,
base::Value* value) OVERRIDE;
virtual void RemoveValue(const std::string& key) OVERRIDE;
virtual bool ReadOnly() const OVERRIDE;
virtual PrefReadError GetReadError() const OVERRIDE;
virtual PrefReadError ReadPrefs() OVERRIDE;
virtual void ReadPrefsAsync(ReadErrorDelegate* error_delegate) OVERRIDE;
virtual void CommitPendingWrite() OVERRIDE;
virtual void ReportValueChanged(const std::string& key) OVERRIDE;
// This method is called after JSON file has been read. Method takes
// ownership of the |value| pointer. Note, this method is used with
// asynchronous file reading, so class exposes it only for the internal needs.
// (read: do not call it manually).
void OnFileRead(base::Value* value_owned, PrefReadError error, bool no_dir);
private:
virtual ~JsonPrefStore();
// ImportantFileWriter::DataSerializer overrides:
virtual bool SerializeData(std::string* output) OVERRIDE;
base::FilePath path_;
const scoped_refptr<base::SequencedTaskRunner> sequenced_task_runner_;
scoped_ptr<base::DictionaryValue> prefs_;
bool read_only_;
// Helper for safely writing pref data.
base::ImportantFileWriter writer_;
ObserverList<PrefStore::Observer, true> observers_;
scoped_ptr<ReadErrorDelegate> error_delegate_;
bool initialized_;
PrefReadError read_error_;
std::set<std::string> keys_need_empty_value_;
DISALLOW_COPY_AND_ASSIGN(JsonPrefStore);
};
#endif // BASE_PREFS_JSON_PREF_STORE_H_
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