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
33namespace blink {
34
35template<typename T> class EventSender {
36    WTF_MAKE_NONCOPYABLE(EventSender); WTF_MAKE_FAST_ALLOCATED;
37public:
38    explicit EventSender(const AtomicString& eventType);
39
40    const AtomicString& eventType() const { return m_eventType; }
41    void dispatchEventSoon(T*);
42    void cancelEvent(T*);
43    void dispatchPendingEvents();
44
45#if ENABLE(ASSERT)
46    bool hasPendingEvents(T* sender) const
47    {
48        return m_dispatchSoonList.find(sender) != kNotFound || m_dispatchingList.find(sender) != kNotFound;
49    }
50#endif
51
52private:
53    void timerFired(Timer<EventSender<T> >*) { dispatchPendingEvents(); }
54
55    AtomicString m_eventType;
56    Timer<EventSender<T> > m_timer;
57    WillBePersistentHeapVector<RawPtrWillBeMember<T> > m_dispatchSoonList;
58    WillBePersistentHeapVector<RawPtrWillBeMember<T> > m_dispatchingList;
59};
60
61template<typename T> EventSender<T>::EventSender(const AtomicString& eventType)
62    : m_eventType(eventType)
63    , m_timer(this, &EventSender::timerFired)
64{
65}
66
67template<typename T> void EventSender<T>::dispatchEventSoon(T* sender)
68{
69    m_dispatchSoonList.append(sender);
70    if (!m_timer.isActive())
71        m_timer.startOneShot(0, FROM_HERE);
72}
73
74template<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] = nullptr;
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] = nullptr;
87    }
88}
89
90template<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] = nullptr;
105            sender->dispatchPendingEvent(this);
106        }
107    }
108    m_dispatchingList.clear();
109}
110
111} // namespace blink
112
113#endif // EventSender_h
114