Source/WebCore/page/DOMWindowProperty.cpp

/*
 * Copyright (C) 2011 Google, Inc. All Rights Reserved.
 * Copyright (C) 2012 Apple Inc. All Rights Reserved.
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 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
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 *    notice, this list of conditions and the following disclaimer in the
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 * 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 INC. OR
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#include "config.h"
#include "DOMWindowProperty.h"

#include "DOMWindow.h"
#include "Document.h"
#include "Frame.h"

namespace WebCore {

DOMWindowProperty::DOMWindowProperty(Frame* frame)
    : m_frame(frame)
    , m_associatedDOMWindow(nullptr)
{
    // FIXME: For now it *is* acceptable for a DOMWindowProperty to be created with a null frame.
    // See fast/dom/navigator-detached-no-crash.html for the recipe.
    // We should fix that.  <rdar://problem/11567132>
    if (m_frame) {
        m_associatedDOMWindow = m_frame->document()->domWindow();
        m_associatedDOMWindow->registerProperty(*this);
    }
}

DOMWindowProperty::~DOMWindowProperty()
{
    if (m_associatedDOMWindow)
        m_associatedDOMWindow->unregisterProperty(*this);

    m_associatedDOMWindow = nullptr;
    m_frame = nullptr;
}

void DOMWindowProperty::disconnectFrameForDocumentSuspension()
{
    // If this property is being disconnected from its Frame to enter the PageCache, it must have
    // been created with a Frame in the first place.
    ASSERT(m_frame);
    ASSERT(m_associatedDOMWindow);

    m_frame = nullptr;
}

void DOMWindowProperty::reconnectFrameFromDocumentSuspension(Frame* frame)
{
    // If this property is being reconnected to its Frame to enter the PageCache, it must have
    // been disconnected from its Frame in the first place and it should still have an associated DOMWindow.
    ASSERT(frame);
    ASSERT(!m_frame);
    ASSERT(frame->document()->domWindow() == m_associatedDOMWindow);

    m_frame = frame;
}

void DOMWindowProperty::willDestroyGlobalObjectInCachedFrame()
{
    // If the property has been disconnected from its Frame for the page cache, then it must have originally had a Frame
    // and therefore should still have an associated DOMWindow.
    ASSERT(!m_frame);
    ASSERT(m_associatedDOMWindow);

    // DOMWindowProperty lifetime isn't tied directly to the DOMWindow itself so it is important that it unregister
    // itself from any DOMWindow it is associated with if that DOMWindow is going away.
    if (m_associatedDOMWindow)
        m_associatedDOMWindow->unregisterProperty(*this);
    m_associatedDOMWindow = nullptr;
    m_frame = nullptr;
}

void DOMWindowProperty::willDestroyGlobalObjectInFrame()
{
    // If the property is getting this callback it must have been created with a Frame/DOMWindow and it should still have them.
    ASSERT(m_frame);
    ASSERT(m_associatedDOMWindow);

    // DOMWindowProperty lifetime isn't tied directly to the DOMWindow itself so it is important that it unregister
    // itself from any DOMWindow it is associated with if that DOMWindow is going away.
    if (m_associatedDOMWindow)
        m_associatedDOMWindow->unregisterProperty(*this);
    m_associatedDOMWindow = nullptr;
    m_frame = nullptr;
}

void DOMWindowProperty::willDetachGlobalObjectFromFrame()
{
    // If the property is getting this callback it must have been created with a Frame/DOMWindow and it should still have them.
    ASSERT(m_frame);
    ASSERT(m_associatedDOMWindow);
}

}