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
37 namespace blink {
38
39 class Visitor;
40
41 template <typename T>
42 class LifecycleContext {
43 public:
44 typedef LifecycleNotifier<T> Notifier;
45 typedef LifecycleObserver<T> Observer;
46
LifecycleContext()47 LifecycleContext() { }
~LifecycleContext()48 virtual ~LifecycleContext() { }
49
isContextThread()50 virtual bool isContextThread() const { return true; }
51
52 // Called from the constructor of observers.
53 void wasObservedBy(Observer*);
54
55 // Called from the destructor of observers.
56 void wasUnobservedBy(Observer*);
57
trace(Visitor *)58 virtual void trace(Visitor*) { }
59
60 protected:
61 Notifier& lifecycleNotifier();
62
63 private:
64 PassOwnPtr<Notifier> createLifecycleNotifier();
65
66 OwnPtr<Notifier> m_lifecycleNotifier;
67 };
68
69 template<typename T>
wasObservedBy(typename LifecycleContext<T>::Observer * observer)70 inline void LifecycleContext<T>::wasObservedBy(typename LifecycleContext<T>::Observer* observer)
71 {
72 ASSERT(isContextThread());
73 lifecycleNotifier().addObserver(observer);
74 }
75
76 template<typename T>
wasUnobservedBy(typename LifecycleContext<T>::Observer * observer)77 inline void LifecycleContext<T>::wasUnobservedBy(typename LifecycleContext<T>::Observer* observer)
78 {
79 ASSERT(isContextThread());
80 lifecycleNotifier().removeObserver(observer);
81 }
82
83 template<typename T>
lifecycleNotifier()84 inline typename LifecycleContext<T>::Notifier& LifecycleContext<T>::lifecycleNotifier()
85 {
86 if (!m_lifecycleNotifier)
87 m_lifecycleNotifier = static_cast<T*>(this)->createLifecycleNotifier();
88 return *m_lifecycleNotifier;
89 }
90
91 template<typename T>
createLifecycleNotifier()92 inline PassOwnPtr<typename LifecycleContext<T>::Notifier> LifecycleContext<T>::createLifecycleNotifier()
93 {
94 return LifecycleContext<T>::Notifier::create(static_cast<T*>(this));
95 }
96
97 } // namespace blink
98
99 #endif // LifecycleContext_h
100