third_party/WebKit/Source/core/dom/custom/CustomElementReactionStack.cpp

// Copyright 2016 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "core/dom/custom/CustomElementReactionStack.h"

#include "bindings/core/v8/Microtask.h"
#include "core/dom/Element.h"
#include "core/dom/custom/CEReactionsScope.h"
#include "core/dom/custom/CustomElementReactionQueue.h"
#include "core/frame/FrameHost.h"

namespace blink {

// TODO(dominicc): Consider using linked heap structures, avoiding
// finalizers, to make short-lived entries fast.

CustomElementReactionStack::CustomElementReactionStack()
{
}

DEFINE_TRACE(CustomElementReactionStack)
{
    visitor->trace(m_map);
    visitor->trace(m_stack);
    visitor->trace(m_backupQueue);
}

void CustomElementReactionStack::push()
{
    m_stack.append(nullptr);
}

void CustomElementReactionStack::popInvokingReactions()
{
    ElementQueue* queue = m_stack.last();
    if (queue)
        invokeReactions(*queue);
    m_stack.removeLast();
}

void CustomElementReactionStack::invokeReactions(ElementQueue& queue)
{
    for (size_t i = 0; i < queue.size(); ++i) {
        Element* element = queue[i];
        if (CustomElementReactionQueue* reactions = m_map.get(element)) {
            reactions->invokeReactions(element);
            CHECK(reactions->isEmpty());
            m_map.remove(element);
        }
    }
}

void CustomElementReactionStack::enqueueToCurrentQueue(
    Element* element,
    CustomElementReaction* reaction)
{
    enqueue(m_stack.last(), element, reaction);
}

void CustomElementReactionStack::enqueue(
    Member<ElementQueue>& queue,
    Element* element,
    CustomElementReaction* reaction)
{
    if (!queue)
        queue = new ElementQueue();
    queue->append(element);

    CustomElementReactionQueue* reactions = m_map.get(element);
    if (!reactions) {
        reactions = new CustomElementReactionQueue();
        m_map.add(element, reactions);
    }

    reactions->add(reaction);
}

void CustomElementReactionStack::enqueueToBackupQueue(
    Element* element,
    CustomElementReaction* reaction)
{
    // https://html.spec.whatwg.org/multipage/scripting.html#backup-element-queue

    DCHECK(!CEReactionsScope::current());
    DCHECK(m_stack.isEmpty());
    DCHECK(isMainThread());

    // If the processing the backup element queue is not set:
    if (!m_backupQueue || m_backupQueue->isEmpty()) {
        Microtask::enqueueMicrotask(WTF::bind(
            &CustomElementReactionStack::invokeBackupQueue,
            Persistent<CustomElementReactionStack>(this)));
    }

    enqueue(m_backupQueue, element, reaction);
}

void CustomElementReactionStack::invokeBackupQueue()
{
    DCHECK(isMainThread());
    invokeReactions(*m_backupQueue);
    m_backupQueue->clear();
}

} // namespace blink