1
2/*
3 * Copyright (C) 2013 Google Inc. All Rights Reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
15 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
17 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
18 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
19 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
20 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
21 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
22 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
24 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 *
26 */
27
28#ifndef LifecycleContext_h
29#define LifecycleContext_h
30
31#include "platform/LifecycleNotifier.h"
32#include "platform/LifecycleObserver.h"
33#include "wtf/HashSet.h"
34#include "wtf/OwnPtr.h"
35#include "wtf/PassOwnPtr.h"
36
37namespace WebCore {
38
39template <typename T>
40class LifecycleContext {
41public:
42    typedef LifecycleNotifier<T> Notifier;
43    typedef LifecycleObserver<T> Observer;
44
45    LifecycleContext() { }
46    virtual ~LifecycleContext() { }
47
48    virtual bool isContextThread() const { return true; }
49
50    // Called from the constructor of observers.
51    void wasObservedBy(Observer*);
52
53    // Called from the destructor of observers.
54    void wasUnobservedBy(Observer*);
55
56protected:
57    Notifier& lifecycleNotifier();
58
59private:
60    PassOwnPtr<Notifier> createLifecycleNotifier();
61
62    OwnPtr<Notifier> m_lifecycleNotifier;
63};
64
65template<typename T>
66inline void LifecycleContext<T>::wasObservedBy(typename LifecycleContext<T>::Observer* observer)
67{
68    ASSERT(isContextThread());
69    lifecycleNotifier().addObserver(observer);
70}
71
72template<typename T>
73inline void LifecycleContext<T>::wasUnobservedBy(typename LifecycleContext<T>::Observer* observer)
74{
75    ASSERT(isContextThread());
76    lifecycleNotifier().removeObserver(observer);
77}
78
79template<typename T>
80inline typename LifecycleContext<T>::Notifier& LifecycleContext<T>::lifecycleNotifier()
81{
82    if (!m_lifecycleNotifier)
83        m_lifecycleNotifier = static_cast<T*>(this)->createLifecycleNotifier();
84    return *m_lifecycleNotifier;
85}
86
87template<typename T>
88inline PassOwnPtr<typename LifecycleContext<T>::Notifier> LifecycleContext<T>::createLifecycleNotifier()
89{
90    return LifecycleContext<T>::Notifier::create(static_cast<T*>(this));
91}
92
93} // namespace WebCore
94
95#endif // LifecycleContext_h
96