third_party/WebKit/Source/core/events/GenericEventQueue.cpp

/*
 * Copyright (C) 2012 Victor Carbune (victor@rosedu.org)
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "core/events/GenericEventQueue.h"

#include "core/events/Event.h"
#include "core/inspector/InspectorInstrumentation.h"
#include "platform/tracing/TraceEvent.h"

namespace blink {

GenericEventQueue* GenericEventQueue::create(EventTarget* owner) {
  return new GenericEventQueue(owner);
}

GenericEventQueue::GenericEventQueue(EventTarget* owner)
    : m_owner(owner),
      m_timer(this, &GenericEventQueue::timerFired),
      m_isClosed(false) {}

GenericEventQueue::~GenericEventQueue() {}

DEFINE_TRACE(GenericEventQueue) {
  visitor->trace(m_owner);
  visitor->trace(m_pendingEvents);
  EventQueue::trace(visitor);
}

bool GenericEventQueue::enqueueEvent(Event* event) {
  if (m_isClosed)
    return false;

  if (event->target() == m_owner)
    event->setTarget(nullptr);

  TRACE_EVENT_ASYNC_BEGIN1("event", "GenericEventQueue:enqueueEvent", event,
                           "type", event->type().ascii());
  EventTarget* target = event->target() ? event->target() : m_owner.get();
  InspectorInstrumentation::asyncTaskScheduled(target->getExecutionContext(),
                                               event->type(), event);
  m_pendingEvents.append(event);

  if (!m_timer.isActive())
    m_timer.startOneShot(0, BLINK_FROM_HERE);

  return true;
}

bool GenericEventQueue::cancelEvent(Event* event) {
  bool found = m_pendingEvents.contains(event);

  if (found) {
    EventTarget* target = event->target() ? event->target() : m_owner.get();
    InspectorInstrumentation::asyncTaskCanceled(target->getExecutionContext(),
                                                event);
    m_pendingEvents.remove(m_pendingEvents.find(event));
    TRACE_EVENT_ASYNC_END2("event", "GenericEventQueue:enqueueEvent", event,
                           "type", event->type().ascii(), "status",
                           "cancelled");
  }

  if (m_pendingEvents.isEmpty())
    m_timer.stop();

  return found;
}

void GenericEventQueue::timerFired(TimerBase*) {
  DCHECK(!m_timer.isActive());
  DCHECK(!m_pendingEvents.isEmpty());

  HeapVector<Member<Event>> pendingEvents;
  m_pendingEvents.swap(pendingEvents);

  for (const auto& pendingEvent : pendingEvents) {
    Event* event = pendingEvent.get();
    EventTarget* target = event->target() ? event->target() : m_owner.get();
    CString type(event->type().ascii());
    InspectorInstrumentation::AsyncTask asyncTask(target->getExecutionContext(),
                                                  event);
    TRACE_EVENT_ASYNC_STEP_INTO1("event", "GenericEventQueue:enqueueEvent",
                                 event, "dispatch", "type", type);
    target->dispatchEvent(pendingEvent);
    TRACE_EVENT_ASYNC_END1("event", "GenericEventQueue:enqueueEvent", event,
                           "type", type);
  }
}

void GenericEventQueue::close() {
  m_isClosed = true;
  cancelAllEvents();
}

void GenericEventQueue::cancelAllEvents() {
  m_timer.stop();

  for (const auto& pendingEvent : m_pendingEvents) {
    Event* event = pendingEvent.get();
    TRACE_EVENT_ASYNC_END2("event", "GenericEventQueue:enqueueEvent", event,
                           "type", event->type().ascii(), "status",
                           "cancelled");
    EventTarget* target = event->target() ? event->target() : m_owner.get();
    InspectorInstrumentation::asyncTaskCanceled(target->getExecutionContext(),
                                                event);
  }
  m_pendingEvents.clear();
}

bool GenericEventQueue::hasPendingEvents() const {
  return m_pendingEvents.size();
}

}  // namespace blink