/*
 * Copyright (C) 2010 Google Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *     * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *     * 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.
 *     * Neither the name of Google Inc. nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "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 THE COPYRIGHT
 * OWNER 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 "config.h"
#include "ScopedEventQueue.h"

#include "Event.h"
#include "Node.h"
#include <wtf/NeverDestroyed.h>

namespace WebCore {

ScopedEventQueue& ScopedEventQueue::singleton()
{
    static NeverDestroyed<ScopedEventQueue> scopedEventQueue;
    return scopedEventQueue;
}

void ScopedEventQueue::enqueueEvent(Ref<Event>&& event)
{
    ASSERT(is<Node>(event->target()));
    auto& target = downcast<Node>(*event->target());
    ScopedEvent scopedEvent = { WTFMove(event), target };
    if (m_scopingLevel)
        m_queuedEvents.append(WTFMove(scopedEvent));
    else
        dispatchEvent(scopedEvent);
}

void ScopedEventQueue::dispatchEvent(const ScopedEvent& event) const
{
    event.target->dispatchEvent(event.event);
}

void ScopedEventQueue::dispatchAllEvents()
{
    auto queuedEvents = std::exchange(m_queuedEvents, { });
    for (auto& queuedEvent : queuedEvents)
        dispatchEvent(queuedEvent);
}

void ScopedEventQueue::incrementScopingLevel()
{
    ++m_scopingLevel;
}

void ScopedEventQueue::decrementScopingLevel()
{
    ASSERT(m_scopingLevel);
    --m_scopingLevel;
    if (!m_scopingLevel)
        dispatchAllEvents();
}

}