1// Copyright (c) 2012 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 CONTENT_PUBLIC_BROWSER_NOTIFICATION_SERVICE_IMPL_H_
6#define CONTENT_PUBLIC_BROWSER_NOTIFICATION_SERVICE_IMPL_H_
7
8#include <map>
9
10#include "base/observer_list.h"
11#include "content/common/content_export.h"
12#include "content/public/browser/notification_service.h"
13
14namespace content {
15
16class NotificationObserver;
17class NotificationRegistrar;
18
19class CONTENT_EXPORT NotificationServiceImpl : public NotificationService {
20 public:
21  static NotificationServiceImpl* current();
22
23  // Normally instantiated when the thread is created.  Not all threads have
24  // a NotificationService.  Only one instance should be created per thread.
25  NotificationServiceImpl();
26  virtual ~NotificationServiceImpl();
27
28  // NotificationService:
29  virtual void Notify(int type,
30                      const NotificationSource& source,
31                      const NotificationDetails& details) OVERRIDE;
32
33 private:
34  friend class NotificationRegistrar;
35
36  typedef ObserverList<NotificationObserver> NotificationObserverList;
37  typedef std::map<uintptr_t, NotificationObserverList*> NotificationSourceMap;
38  typedef std::map<int, NotificationSourceMap> NotificationObserverMap;
39  typedef std::map<int, int> NotificationObserverCount;
40
41  // Convenience function to determine whether a source has a
42  // NotificationObserverList in the given map;
43  static bool HasKey(const NotificationSourceMap& map,
44                     const NotificationSource& source);
45
46  // NOTE: Rather than using this directly, you should use a
47  // NotificationRegistrar.
48  //
49  // Registers a NotificationObserver to be called whenever a matching
50  // notification is posted.  Observer is a pointer to an object subclassing
51  // NotificationObserver to be notified when an event matching the other two
52  // parameters is posted to this service.  Type is the type of events to be
53  // notified about (or NOTIFICATION_ALL to receive events of all
54  // types).
55  // Source is a NotificationSource object (created using
56  // "Source<classname>(pointer)"), if this observer only wants to
57  // receive events from that object, or NotificationService::AllSources()
58  // to receive events from all sources.
59  //
60  // A given observer can be registered only once for each combination of
61  // type and source.  If the same object is registered more than once,
62  // it must be removed for each of those combinations of type and source later.
63  //
64  // The caller retains ownership of the object pointed to by observer.
65  void AddObserver(NotificationObserver* observer,
66                   int type,
67                   const NotificationSource& source);
68
69  // NOTE: Rather than using this directly, you should use a
70  // NotificationRegistrar.
71  //
72  // Removes the object pointed to by observer from receiving notifications
73  // that match type and source.  If no object matching the parameters is
74  // currently registered, this method is a no-op.
75  void RemoveObserver(NotificationObserver* observer,
76                      int type,
77                      const NotificationSource& source);
78
79  // Keeps track of the observers for each type of notification.
80  // Until we get a prohibitively large number of notification types,
81  // a simple array is probably the fastest way to dispatch.
82  NotificationObserverMap observers_;
83
84#ifndef NDEBUG
85  // Used to check to see that AddObserver and RemoveObserver calls are
86  // balanced.
87  NotificationObserverCount observer_counts_;
88#endif
89
90  DISALLOW_COPY_AND_ASSIGN(NotificationServiceImpl);
91};
92
93}  // namespace content
94
95#endif  // CONTENT_PUBLIC_BROWSER_NOTIFICATION_SERVICE_IMPL_H_
96