third_party/WebKit/Source/core/dom/TreeScopeAdopter.cpp

/*
 * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
 *           (C) 1999 Antti Koivisto (koivisto@kde.org)
 *           (C) 2001 Dirk Mueller (mueller@kde.org)
 * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
 * Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies)
 * Copyright (C) 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
 * Copyright (C) 2011 Google Inc. All rights reserved.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public License
 * along with this library; see the file COPYING.LIB.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 */
#include "core/dom/TreeScopeAdopter.h"

#include "core/dom/Attr.h"
#include "core/dom/Node.h"
#include "core/dom/NodeRareData.h"
#include "core/dom/NodeTraversal.h"
#include "core/dom/custom/CustomElement.h"
#include "core/dom/shadow/ElementShadow.h"
#include "core/dom/shadow/ShadowRoot.h"

namespace blink {

void TreeScopeAdopter::moveTreeToNewScope(Node& root) const
{
    DCHECK(needsScopeChange());

    // If an element is moved from a document and then eventually back again the collection cache for
    // that element may contain stale data as changes made to it will have updated the DOMTreeVersion
    // of the document it was moved to. By increasing the DOMTreeVersion of the donating document here
    // we ensure that the collection cache will be invalidated as needed when the element is moved back.
    Document& oldDocument = oldScope().document();
    Document& newDocument = newScope().document();
    bool willMoveToNewDocument = oldDocument != newDocument;
    if (willMoveToNewDocument)
        oldDocument.incDOMTreeVersion();

    for (Node& node : NodeTraversal::inclusiveDescendantsOf(root)) {
        updateTreeScope(node);

        if (willMoveToNewDocument) {
            moveNodeToNewDocument(node, oldDocument, newDocument);
        } else if (node.hasRareData()) {
            NodeRareData* rareData = node.rareData();
            if (rareData->nodeLists())
                rareData->nodeLists()->adoptTreeScope();
        }

        if (!node.isElementNode())
            continue;
        Element& element = toElement(node);

        if (HeapVector<Member<Attr>>* attrs = element.attrNodeList()) {
            for (const auto& attr : *attrs)
                moveTreeToNewScope(*attr);
        }

        for (ShadowRoot* shadow = element.youngestShadowRoot(); shadow; shadow = shadow->olderShadowRoot()) {
            shadow->setParentTreeScope(newScope());
            if (willMoveToNewDocument)
                moveTreeToNewDocument(*shadow, oldDocument, newDocument);
        }
    }
    if (!willMoveToNewDocument)
        return;
    oldDocument.didMoveTreeToNewDocument(root);
}

void TreeScopeAdopter::moveTreeToNewDocument(Node& root, Document& oldDocument, Document& newDocument) const
{
    DCHECK_NE(oldDocument, newDocument);
    for (Node& node : NodeTraversal::inclusiveDescendantsOf(root)) {
        moveNodeToNewDocument(node, oldDocument, newDocument);

        if (!node.isElementNode())
            continue;
        Element& element = toElement(node);

        if (HeapVector<Member<Attr>>* attrs = element.attrNodeList()) {
            for (const auto& attr : *attrs)
                moveTreeToNewDocument(*attr, oldDocument, newDocument);
        }

        for (ShadowRoot* shadow = element.youngestShadowRoot(); shadow; shadow = shadow->olderShadowRoot())
            moveTreeToNewDocument(*shadow, oldDocument, newDocument);
    }
}

#if DCHECK_IS_ON()
static bool didMoveToNewDocumentWasCalled = false;
static Document* oldDocumentDidMoveToNewDocumentWasCalledWith = 0;

void TreeScopeAdopter::ensureDidMoveToNewDocumentWasCalled(Document& oldDocument)
{
    DCHECK(!didMoveToNewDocumentWasCalled);
    ASSERT_UNUSED(oldDocument, oldDocument == oldDocumentDidMoveToNewDocumentWasCalledWith);
    didMoveToNewDocumentWasCalled = true;
}
#endif

inline void TreeScopeAdopter::updateTreeScope(Node& node) const
{
    DCHECK(!node.isTreeScope());
    DCHECK(node.treeScope() == oldScope());
    node.setTreeScope(m_newScope);
}

inline void TreeScopeAdopter::moveNodeToNewDocument(Node& node, Document& oldDocument, Document& newDocument) const
{
    DCHECK_NE(oldDocument, newDocument);

    if (node.hasRareData()) {
        NodeRareData* rareData = node.rareData();
        if (rareData->nodeLists())
            rareData->nodeLists()->adoptDocument(oldDocument, newDocument);
    }

    oldDocument.moveNodeIteratorsToNewDocument(node, newDocument);

    if (node.getCustomElementState() == CustomElementState::Custom) {
        Element& element = toElement(node);
        CustomElement::enqueueAdoptedCallback(&element);
    }

    if (node.isShadowRoot())
        toShadowRoot(node).setDocument(newDocument);

#if DCHECK_IS_ON()
    didMoveToNewDocumentWasCalled = false;
    oldDocumentDidMoveToNewDocumentWasCalledWith = &oldDocument;
#endif

    node.didMoveToNewDocument(oldDocument);
#if DCHECK_IS_ON()
    DCHECK(didMoveToNewDocumentWasCalled);
#endif
}

} // namespace blink