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      1 /*
      2  * Copyright (C) 2010 Google 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 COMPUTER, INC. ``AS IS'' AND ANY
     14  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     16  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
     17  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
     18  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
     19  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
     20  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
     21  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     23  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     24  *
     25  */
     26 
     27 #include "config.h"
     28 #include "EventQueue.h"
     29 
     30 #include "DOMWindow.h"
     31 #include "Document.h"
     32 #include "Event.h"
     33 #include "EventNames.h"
     34 #include "RuntimeApplicationChecks.h"
     35 #include "ScriptExecutionContext.h"
     36 #include "SuspendableTimer.h"
     37 
     38 namespace WebCore {
     39 
     40 static inline bool shouldDispatchScrollEventSynchronously(Document* document)
     41 {
     42     ASSERT_ARG(document, document);
     43     return applicationIsSafari() && (document->url().protocolIs("feed") || document->url().protocolIs("feeds"));
     44 }
     45 
     46 class EventQueueTimer : public SuspendableTimer {
     47     WTF_MAKE_NONCOPYABLE(EventQueueTimer);
     48 public:
     49     EventQueueTimer(EventQueue* eventQueue, ScriptExecutionContext* context)
     50         : SuspendableTimer(context)
     51         , m_eventQueue(eventQueue) { }
     52 
     53 private:
     54     virtual void fired() { m_eventQueue->pendingEventTimerFired(); }
     55     EventQueue* m_eventQueue;
     56 };
     57 
     58 PassRefPtr<EventQueue> EventQueue::create(ScriptExecutionContext* context)
     59 {
     60     return adoptRef(new EventQueue(context));
     61 }
     62 
     63 EventQueue::EventQueue(ScriptExecutionContext* context)
     64     : m_pendingEventTimer(adoptPtr(new EventQueueTimer(this, context)))
     65 {
     66 }
     67 
     68 EventQueue::~EventQueue()
     69 {
     70 }
     71 
     72 void EventQueue::enqueueEvent(PassRefPtr<Event> event)
     73 {
     74     ASSERT(event->target());
     75     bool wasAdded = m_queuedEvents.add(event).second;
     76     ASSERT_UNUSED(wasAdded, wasAdded); // It should not have already been in the list.
     77 
     78     if (!m_pendingEventTimer->isActive())
     79         m_pendingEventTimer->startOneShot(0);
     80 }
     81 
     82 void EventQueue::enqueueOrDispatchScrollEvent(PassRefPtr<Node> target, ScrollEventTargetType targetType)
     83 {
     84     // Per the W3C CSSOM View Module, scroll events fired at the document should bubble, others should not.
     85     bool canBubble = targetType == ScrollEventDocumentTarget;
     86     RefPtr<Event> scrollEvent = Event::create(eventNames().scrollEvent, canBubble, false /* non cancelleable */);
     87 
     88     if (shouldDispatchScrollEventSynchronously(target->document())) {
     89         target->dispatchEvent(scrollEvent.release());
     90         return;
     91     }
     92 
     93     if (!m_nodesWithQueuedScrollEvents.add(target.get()).second)
     94         return;
     95 
     96     scrollEvent->setTarget(target);
     97     enqueueEvent(scrollEvent.release());
     98 }
     99 
    100 bool EventQueue::cancelEvent(Event* event)
    101 {
    102     bool found = m_queuedEvents.contains(event);
    103     m_queuedEvents.remove(event);
    104     if (m_queuedEvents.isEmpty())
    105         m_pendingEventTimer->stop();
    106     return found;
    107 }
    108 
    109 void EventQueue::cancelQueuedEvents()
    110 {
    111     m_pendingEventTimer->stop();
    112     m_queuedEvents.clear();
    113 }
    114 
    115 void EventQueue::pendingEventTimerFired()
    116 {
    117     ASSERT(!m_pendingEventTimer->isActive());
    118     ASSERT(!m_queuedEvents.isEmpty());
    119 
    120     m_nodesWithQueuedScrollEvents.clear();
    121 
    122     // Insert a marker for where we should stop.
    123     ASSERT(!m_queuedEvents.contains(0));
    124     bool wasAdded = m_queuedEvents.add(0).second;
    125     ASSERT_UNUSED(wasAdded, wasAdded); // It should not have already been in the list.
    126 
    127     RefPtr<EventQueue> protector(this);
    128 
    129     while (!m_queuedEvents.isEmpty()) {
    130         ListHashSet<RefPtr<Event> >::iterator iter = m_queuedEvents.begin();
    131         RefPtr<Event> event = *iter;
    132         m_queuedEvents.remove(iter);
    133         if (!event)
    134             break;
    135         dispatchEvent(event.get());
    136     }
    137 }
    138 
    139 void EventQueue::dispatchEvent(PassRefPtr<Event> event)
    140 {
    141     EventTarget* eventTarget = event->target();
    142     if (eventTarget->toDOMWindow())
    143         eventTarget->toDOMWindow()->dispatchEvent(event, 0);
    144     else
    145         eventTarget->dispatchEvent(event);
    146 }
    147 
    148 }
    149