1// Copyright 2013 The Chromium Authors. All rights reserved. 2// Use of this source code is governed by a BSD-style license that can be 3// found in the LICENSE file. 4 5#ifndef CHROME_BROWSER_PREFS_SYNCED_PREF_CHANGE_REGISTRAR_H_ 6#define CHROME_BROWSER_PREFS_SYNCED_PREF_CHANGE_REGISTRAR_H_ 7 8#include <map> 9#include <string> 10 11#include "base/callback.h" 12#include "chrome/browser/prefs/pref_service_syncable.h" 13#include "chrome/browser/prefs/synced_pref_observer.h" 14 15// Manages the registration of one or more SyncedPrefObservers on a 16// PrefServiceSyncable. This is modeled after base::PrefChangeRegistrar, and 17// it should be used whenever it's necessary to determine whether a pref change 18// has come from sync or from some other mechanism (managed, UI, external, etc.) 19class SyncedPrefChangeRegistrar : public SyncedPrefObserver { 20 public: 21 // Registered callbacks may optionally take a path argument. 22 // The boolean argument indicates whether (true) or not (false) 23 // the change was a result of syncing. 24 typedef base::Callback<void(bool)> ChangeCallback; 25 typedef base::Callback<void(const std::string&, bool)> NamedChangeCallback; 26 27 explicit SyncedPrefChangeRegistrar(PrefServiceSyncable* pref_service); 28 virtual ~SyncedPrefChangeRegistrar(); 29 30 // Register an observer callback for sync change events on the pref at 31 // |path|. Only one callback may be registered per pref. 32 void Add(const char* path, const ChangeCallback& callback); 33 void Add(const char* path, const NamedChangeCallback& callback); 34 35 // Remove the registered observer for |path|. 36 void Remove(const char* path); 37 38 // Remove all registered observers. 39 void RemoveAll(); 40 41 // Indicates whether or not an observer is already registered for |path|. 42 bool IsObserved(const char* path) const; 43 44 private: 45 // SyncedPrefObserver implementation 46 virtual void OnSyncedPrefChanged(const std::string& path, bool from_sync) 47 OVERRIDE; 48 49 typedef std::map<std::string, NamedChangeCallback> ObserverMap; 50 51 PrefServiceSyncable* pref_service_; 52 ObserverMap observers_; 53 54 DISALLOW_COPY_AND_ASSIGN(SyncedPrefChangeRegistrar); 55}; 56 57#endif // CHROME_BROWSER_PREFS_SYNCED_PREF_CHANGE_REGISTRAR_H_ 58