1// Copyright (c) 2010 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_PREF_NOTIFIER_IMPL_H_
6#define CHROME_BROWSER_PREFS_PREF_NOTIFIER_IMPL_H_
7#pragma once
8
9#include <string>
10
11#include "base/hash_tables.h"
12#include "base/observer_list.h"
13#include "base/threading/non_thread_safe.h"
14#include "chrome/browser/prefs/pref_notifier.h"
15
16class PrefService;
17class NotificationObserver;
18
19// The PrefNotifier implementation used by the PrefService.
20class PrefNotifierImpl : public PrefNotifier,
21                         public base::NonThreadSafe {
22 public:
23  explicit PrefNotifierImpl(PrefService* pref_service);
24  virtual ~PrefNotifierImpl();
25
26  // If the pref at the given path changes, we call the observer's Observe
27  // method with PREF_CHANGED.
28  void AddPrefObserver(const char* path, NotificationObserver* obs);
29  void RemovePrefObserver(const char* path, NotificationObserver* obs);
30
31  // PrefNotifier overrides.
32  virtual void OnPreferenceChanged(const std::string& pref_name);
33  virtual void OnInitializationCompleted();
34
35 protected:
36  // A map from pref names to a list of observers. Observers get fired in the
37  // order they are added. These should only be accessed externally for unit
38  // testing.
39  typedef ObserverList<NotificationObserver> NotificationObserverList;
40  typedef base::hash_map<std::string, NotificationObserverList*>
41      PrefObserverMap;
42
43  const PrefObserverMap* pref_observers() const { return &pref_observers_; }
44
45 private:
46  // For the given pref_name, fire any observer of the pref. Virtual so it can
47  // be mocked for unit testing.
48  virtual void FireObservers(const std::string& path);
49
50  // Weak reference; the notifier is owned by the PrefService.
51  PrefService* pref_service_;
52
53  PrefObserverMap pref_observers_;
54
55  DISALLOW_COPY_AND_ASSIGN(PrefNotifierImpl);
56};
57
58#endif  // CHROME_BROWSER_PREFS_PREF_NOTIFIER_IMPL_H_
59