1 /*
2 * Copyright (C) 2012 Apple Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
14 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
15 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
17 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
18 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
19 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
20 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
21 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
22 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
23 * THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26 #ifndef EventSender_h
27 #define EventSender_h
28
29 #include "platform/Timer.h"
30 #include "wtf/Vector.h"
31 #include "wtf/text/AtomicString.h"
32
33 namespace WebCore {
34
35 template<typename T> class EventSender {
36 WTF_MAKE_NONCOPYABLE(EventSender); WTF_MAKE_FAST_ALLOCATED;
37 public:
38 explicit EventSender(const AtomicString& eventType);
39
eventType()40 const AtomicString& eventType() const { return m_eventType; }
41 void dispatchEventSoon(T*);
42 void cancelEvent(T*);
43 void dispatchPendingEvents();
44
45 #ifndef NDEBUG
hasPendingEvents(T * sender)46 bool hasPendingEvents(T* sender) const
47 {
48 return m_dispatchSoonList.find(sender) != kNotFound || m_dispatchingList.find(sender) != kNotFound;
49 }
50 #endif
51
52 private:
timerFired(Timer<EventSender<T>> *)53 void timerFired(Timer<EventSender<T> >*) { dispatchPendingEvents(); }
54
55 AtomicString m_eventType;
56 Timer<EventSender<T> > m_timer;
57 Vector<T*> m_dispatchSoonList;
58 Vector<T*> m_dispatchingList;
59 };
60
EventSender(const AtomicString & eventType)61 template<typename T> EventSender<T>::EventSender(const AtomicString& eventType)
62 : m_eventType(eventType)
63 , m_timer(this, &EventSender::timerFired)
64 {
65 }
66
dispatchEventSoon(T * sender)67 template<typename T> void EventSender<T>::dispatchEventSoon(T* sender)
68 {
69 m_dispatchSoonList.append(sender);
70 if (!m_timer.isActive())
71 m_timer.startOneShot(0);
72 }
73
cancelEvent(T * sender)74 template<typename T> void EventSender<T>::cancelEvent(T* sender)
75 {
76 // Remove instances of this sender from both lists.
77 // Use loops because we allow multiple instances to get into the lists.
78 size_t size = m_dispatchSoonList.size();
79 for (size_t i = 0; i < size; ++i) {
80 if (m_dispatchSoonList[i] == sender)
81 m_dispatchSoonList[i] = 0;
82 }
83 size = m_dispatchingList.size();
84 for (size_t i = 0; i < size; ++i) {
85 if (m_dispatchingList[i] == sender)
86 m_dispatchingList[i] = 0;
87 }
88 }
89
dispatchPendingEvents()90 template<typename T> void EventSender<T>::dispatchPendingEvents()
91 {
92 // Need to avoid re-entering this function; if new dispatches are
93 // scheduled before the parent finishes processing the list, they
94 // will set a timer and eventually be processed.
95 if (!m_dispatchingList.isEmpty())
96 return;
97
98 m_timer.stop();
99
100 m_dispatchingList.swap(m_dispatchSoonList);
101 size_t size = m_dispatchingList.size();
102 for (size_t i = 0; i < size; ++i) {
103 if (T* sender = m_dispatchingList[i]) {
104 m_dispatchingList[i] = 0;
105 sender->dispatchPendingEvent(this);
106 }
107 }
108 m_dispatchingList.clear();
109 }
110
111 } // namespace WebCore
112
113 #endif // EventSender_h
114