blob: 0baf02ac8916713b3557f226a32dcdb9639958d2 [file] [log] [blame]
// 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.
#include <string>
#include "base/prefs/base_prefs_export.h"
#include "base/prefs/pref_store.h"
// This interface is complementary to the PrefStore interface, declaring
// additional functionality that adds support for setting values and persisting
// the data to some backing store.
class BASE_PREFS_EXPORT PersistentPrefStore : public PrefStore {
// Unique integer code for each type of error so we can report them
// distinctly in a histogram.
// NOTE: Don't change the order here as it will change the server's meaning
// of the histogram.
enum PrefReadError {
class ReadErrorDelegate {
virtual ~ReadErrorDelegate() {}
virtual void OnError(PrefReadError error) = 0;
// Equivalent to PrefStore::GetValue but returns a mutable value.
virtual bool GetMutableValue(const std::string& key,
base::Value** result) = 0;
// Triggers a value changed notification. This function needs to be called
// if one retrieves a list or dictionary with GetMutableValue and change its
// value. SetValue takes care of notifications itself. Note that
// ReportValueChanged will trigger notifications even if nothing has changed.
virtual void ReportValueChanged(const std::string& key) = 0;
// Sets a |value| for |key| in the store. Assumes ownership of |value|, which
// must be non-NULL.
virtual void SetValue(const std::string& key, base::Value* value) = 0;
// Same as SetValue, but doesn't generate notifications. This is used by
// PrefService::GetMutableUserPref() in order to put empty entries
// into the user pref store. Using SetValue is not an option since existing
// tests rely on the number of notifications generated.
virtual void SetValueSilently(const std::string& key, base::Value* value) = 0;
// Removes the value for |key|.
virtual void RemoveValue(const std::string& key) = 0;
// Marks that the |key| with empty ListValue/DictionaryValue needs to be
// persisted.
virtual void MarkNeedsEmptyValue(const std::string& key) = 0;
// Whether the store is in a pseudo-read-only mode where changes are not
// actually persisted to disk. This happens in some cases when there are
// read errors during startup.
virtual bool ReadOnly() const = 0;
// Gets the read error. Only valid if IsInitializationComplete() returns true.
virtual PrefReadError GetReadError() const = 0;
// Reads the preferences from disk. Notifies observers via
// "PrefStore::OnInitializationCompleted" when done.
virtual PrefReadError ReadPrefs() = 0;
// Reads the preferences from disk asynchronously. Notifies observers via
// "PrefStore::OnInitializationCompleted" when done. Also it fires
// |error_delegate| if it is not NULL and reading error has occurred.
// Owns |error_delegate|.
virtual void ReadPrefsAsync(ReadErrorDelegate* error_delegate) = 0;
// Lands any pending writes to disk.
virtual void CommitPendingWrite() = 0;
virtual ~PersistentPrefStore() {}