Source/core/dom/NodeRareData.cpp

/*
 * Copyright (C) 2012 Google Inc. All rights reserved.
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#include "config.h"
#include "core/dom/NodeRareData.h"
#include "core/dom/Element.h"
#include "core/dom/ElementRareData.h"
#include "core/frame/FrameHost.h"
#include "core/rendering/RenderObject.h"
#include "platform/heap/Handle.h"

namespace blink {

struct SameSizeAsNodeRareData {
    void* m_pointer[2];
    OwnPtrWillBeMember<NodeMutationObserverData> m_mutationObserverData;
    unsigned m_bitfields;
};

static_assert(sizeof(NodeRareData) == sizeof(SameSizeAsNodeRareData), "NodeRareData should stay small");

void NodeRareData::traceAfterDispatch(Visitor* visitor)
{
#if ENABLE(OILPAN)
    visitor->trace(m_renderer);
#endif
    visitor->trace(m_mutationObserverData);
    // Do not keep empty NodeListsNodeData objects around.
    if (m_nodeLists && m_nodeLists->isEmpty())
        m_nodeLists.clear();
    else
        visitor->trace(m_nodeLists);
}

void NodeRareData::trace(Visitor* visitor)
{
    if (m_isElementRareData)
        static_cast<ElementRareData*>(this)->traceAfterDispatch(visitor);
    else
        traceAfterDispatch(visitor);
}

void NodeRareData::finalizeGarbageCollectedObject()
{
    RELEASE_ASSERT(!renderer());
    if (m_isElementRareData)
        static_cast<ElementRareData*>(this)->~ElementRareData();
    else
        this->~NodeRareData();
}

// Ensure the 10 bits reserved for the m_connectedFrameCount cannot overflow
static_assert(FrameHost::maxNumberOfFrames < (1 << NodeRareData::ConnectedFrameCountBits), "Frame limit should fit in rare data count");

} // namespace blink