Source/core/dom/CustomElementCallbackDispatcher.cpp

/*
 * Copyright (C) 2013 Google Inc. All rights reserved.
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 * modification, are permitted provided that the following conditions
 * are met:
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 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
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 *    notice, this list of conditions and the following disclaimer
 *    in the documentation and/or other materials provided with the
 *    distribution.
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 *    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
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#include "config.h"
#include "core/dom/CustomElementCallbackDispatcher.h"

#include "core/dom/CustomElementCallbackQueue.h"
#include "core/dom/CustomElementCallbackScheduler.h"
#include "wtf/MainThread.h"

namespace WebCore {

size_t CustomElementCallbackDispatcher::s_elementQueueStart = 0;

// The base of the stack has a null sentinel value.
size_t CustomElementCallbackDispatcher::s_elementQueueEnd = kNumSentinels;

CustomElementCallbackDispatcher& CustomElementCallbackDispatcher::instance()
{
    DEFINE_STATIC_LOCAL(CustomElementCallbackDispatcher, instance, ());
    return instance;
}

// Dispatches callbacks at microtask checkpoint.
bool CustomElementCallbackDispatcher::dispatch()
{
    ASSERT(isMainThread());
    if (inCallbackDeliveryScope())
        return false;

    size_t start = kNumSentinels; // skip null sentinel
    size_t end = s_elementQueueEnd;
    ElementQueue thisQueue = currentElementQueue();

    for (size_t i = start; i < end; i++) {
        {
            // The created callback may schedule entered document
            // callbacks.
            CallbackDeliveryScope deliveryScope;
            m_flattenedProcessingStack[i]->processInElementQueue(thisQueue);
        }

        ASSERT(!s_elementQueueStart);
        ASSERT(s_elementQueueEnd == end);
    }

    s_elementQueueEnd = kNumSentinels;
    m_flattenedProcessingStack.resize(s_elementQueueEnd);

    CustomElementCallbackScheduler::clearElementCallbackQueueMap();

    bool didWork = start < end;
    return didWork;
}

// Dispatches callbacks when popping the processing stack.
void CustomElementCallbackDispatcher::processElementQueueAndPop()
{
    instance().processElementQueueAndPop(s_elementQueueStart, s_elementQueueEnd);
}

void CustomElementCallbackDispatcher::processElementQueueAndPop(size_t start, size_t end)
{
    ASSERT(isMainThread());
    ElementQueue thisQueue = currentElementQueue();

    for (size_t i = start; i < end; i++) {
        {
            // The created callback may schedule entered document
            // callbacks.
            CallbackDeliveryScope deliveryScope;
            m_flattenedProcessingStack[i]->processInElementQueue(thisQueue);
        }

        ASSERT(start == s_elementQueueStart);
        ASSERT(end == s_elementQueueEnd);
    }

    // Pop the element queue from the processing stack
    m_flattenedProcessingStack.resize(start);
    s_elementQueueEnd = start;

    if (start == kNumSentinels)
        CustomElementCallbackScheduler::clearElementCallbackQueueMap();
}

void CustomElementCallbackDispatcher::enqueue(CustomElementCallbackQueue* callbackQueue)
{
    if (callbackQueue->owner() == currentElementQueue())
        return;

    callbackQueue->setOwner(currentElementQueue());
    m_flattenedProcessingStack.append(callbackQueue);
    ++s_elementQueueEnd;
}

} // namespace WebCore