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 "Timer.h"
30#include <wtf/Vector.h>
31
32namespace WebCore {
33
34template<typename T> class EventSender {
35    WTF_MAKE_NONCOPYABLE(EventSender); WTF_MAKE_FAST_ALLOCATED;
36public:
37    explicit EventSender(const AtomicString& eventType);
38
39    const AtomicString& eventType() const { return m_eventType; }
40    void dispatchEventSoon(T*);
41    void cancelEvent(T*);
42    void dispatchPendingEvents();
43
44#ifndef NDEBUG
45    bool hasPendingEvents(T* sender) const
46    {
47        return m_dispatchSoonList.find(sender) != notFound || m_dispatchingList.find(sender) != notFound;
48    }
49#endif
50
51private:
52    void timerFired(Timer<EventSender<T>>&) { dispatchPendingEvents(); }
53
54    AtomicString m_eventType;
55    Timer<EventSender<T>> m_timer;
56    Vector<T*> m_dispatchSoonList;
57    Vector<T*> m_dispatchingList;
58};
59
60template<typename T> EventSender<T>::EventSender(const AtomicString& eventType)
61    : m_eventType(eventType)
62    , m_timer(this, &EventSender::timerFired)
63{
64}
65
66template<typename T> void EventSender<T>::dispatchEventSoon(T* sender)
67{
68    m_dispatchSoonList.append(sender);
69    if (!m_timer.isActive())
70        m_timer.startOneShot(0);
71}
72
73template<typename T> void EventSender<T>::cancelEvent(T* sender)
74{
75    // Remove instances of this sender from both lists.
76    // Use loops because we allow multiple instances to get into the lists.
77    size_t size = m_dispatchSoonList.size();
78    for (size_t i = 0; i < size; ++i) {
79        if (m_dispatchSoonList[i] == sender)
80            m_dispatchSoonList[i] = 0;
81    }
82    size = m_dispatchingList.size();
83    for (size_t i = 0; i < size; ++i) {
84        if (m_dispatchingList[i] == sender)
85            m_dispatchingList[i] = 0;
86    }
87}
88
89template<typename T> void EventSender<T>::dispatchPendingEvents()
90{
91    // Need to avoid re-entering this function; if new dispatches are
92    // scheduled before the parent finishes processing the list, they
93    // will set a timer and eventually be processed.
94    if (!m_dispatchingList.isEmpty())
95        return;
96
97    m_timer.stop();
98
99    m_dispatchSoonList.checkConsistency();
100
101    m_dispatchingList.swap(m_dispatchSoonList);
102    size_t size = m_dispatchingList.size();
103    for (size_t i = 0; i < size; ++i) {
104        if (T* sender = m_dispatchingList[i]) {
105            m_dispatchingList[i] = 0;
106            sender->dispatchPendingEvent(this);
107        }
108    }
109    m_dispatchingList.clear();
110}
111
112} // namespace WebCore
113
114#endif // EventSender_h
115