/*
 * 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 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/)
 *
 * 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 "config.h"
#include "Node.h"

#include "AXObjectCache.h"
#include "Attr.h"
#include "Attribute.h"
#include "CSSParser.h"
#include "CSSRule.h"
#include "CSSRuleList.h"
#include "CSSSelector.h"
#include "CSSSelectorList.h"
#include "CSSStyleRule.h"
#include "CSSStyleSelector.h"
#include "CSSStyleSheet.h"
#include "ChildNodeList.h"
#include "ClassNodeList.h"
#include "ContextMenuController.h"
#include "DOMImplementation.h"
#include "Document.h"
#include "DocumentType.h"
#include "DynamicNodeList.h"
#include "Element.h"
#include "Event.h"
#include "EventContext.h"
#include "EventDispatcher.h"
#include "EventException.h"
#include "EventHandler.h"
#include "EventListener.h"
#include "EventNames.h"
#include "ExceptionCode.h"
#include "Frame.h"
#include "FrameView.h"
#include "HTMLElement.h"
#include "HTMLNames.h"
#include "InspectorInstrumentation.h"
#include "KeyboardEvent.h"
#include "LabelsNodeList.h"
#include "Logging.h"
#include "MouseEvent.h"
#include "MutationEvent.h"
#include "NameNodeList.h"
#include "NamedNodeMap.h"
#include "NodeRareData.h"
#include "Page.h"
#include "PlatformMouseEvent.h"
#include "PlatformWheelEvent.h"
#include "ProcessingInstruction.h"
#include "ProgressEvent.h"
#include "RegisteredEventListener.h"
#include "RenderBlock.h"
#include "RenderBox.h"
#include "RenderFullScreen.h"
#include "RenderTextControl.h"
#include "RenderView.h"
#include "ScopedEventQueue.h"
#include "SelectorNodeList.h"
#include "ShadowRoot.h"
#include "StaticNodeList.h"
#include "TagNodeList.h"
#include "Text.h"
#include "TextEvent.h"
#include "UIEvent.h"
#include "UIEventWithKeyState.h"
#include "WebKitAnimationEvent.h"
#include "WebKitTransitionEvent.h"
#include "WheelEvent.h"
#include "WindowEventContext.h"
#include "XMLNames.h"
#include "htmlediting.h"
#include <wtf/HashSet.h>
#include <wtf/PassOwnPtr.h>
#include <wtf/RefCountedLeakCounter.h>
#include <wtf/UnusedParam.h>
#include <wtf/text/CString.h>
#include <wtf/text/StringBuilder.h>

#if ENABLE(DOM_STORAGE)
#include "StorageEvent.h"
#endif

#if ENABLE(SVG)
#include "SVGElementInstance.h"
#include "SVGUseElement.h"
#endif

#if ENABLE(XHTMLMP)
#include "HTMLNoScriptElement.h"
#endif

#if USE(JSC)
#include <runtime/JSGlobalData.h>
#endif

#define DUMP_NODE_STATISTICS 0

using namespace std;

namespace WebCore {

using namespace HTMLNames;

bool Node::isSupported(const String& feature, const String& version)
{
    return DOMImplementation::hasFeature(feature, version);
}

#if DUMP_NODE_STATISTICS
static HashSet<Node*> liveNodeSet;
#endif

void Node::dumpStatistics()
{
#if DUMP_NODE_STATISTICS
    size_t nodesWithRareData = 0;

    size_t elementNodes = 0;
    size_t attrNodes = 0;
    size_t textNodes = 0;
    size_t cdataNodes = 0;
    size_t commentNodes = 0;
    size_t entityReferenceNodes = 0;
    size_t entityNodes = 0;
    size_t piNodes = 0;
    size_t documentNodes = 0;
    size_t docTypeNodes = 0;
    size_t fragmentNodes = 0;
    size_t notationNodes = 0;
    size_t xpathNSNodes = 0;
    size_t shadowRootNodes = 0;

    HashMap<String, size_t> perTagCount;

    size_t attributes = 0;
    size_t mappedAttributes = 0;
    size_t mappedAttributesWithStyleDecl = 0;
    size_t attributesWithAttr = 0;
    size_t attrMaps = 0;

    for (HashSet<Node*>::iterator it = liveNodeSet.begin(); it != liveNodeSet.end(); ++it) {
        Node* node = *it;

        if (node->hasRareData())
            ++nodesWithRareData;

        switch (node->nodeType()) {
            case ELEMENT_NODE: {
                ++elementNodes;

                // Tag stats
                Element* element = static_cast<Element*>(node);
                pair<HashMap<String, size_t>::iterator, bool> result = perTagCount.add(element->tagName(), 1);
                if (!result.second)
                    result.first->second++;

                // AttributeMap stats
                if (NamedNodeMap* attrMap = element->attributes(true)) {
                    attributes += attrMap->length();
                    ++attrMaps;
                    for (unsigned i = 0; i < attrMap->length(); ++i) {
                        Attribute* attr = attrMap->attributeItem(i);
                        if (attr->attr())
                            ++attributesWithAttr;
                        if (attr->isMappedAttribute()) {
                            ++mappedAttributes;
                            if (attr->style())
                                ++mappedAttributesWithStyleDecl;
                        }
                    }
                }
                break;
            }
            case ATTRIBUTE_NODE: {
                ++attrNodes;
                break;
            }
            case TEXT_NODE: {
                ++textNodes;
                break;
            }
            case CDATA_SECTION_NODE: {
                ++cdataNodes;
                break;
            }
            case COMMENT_NODE: {
                ++commentNodes;
                break;
            }
            case ENTITY_REFERENCE_NODE: {
                ++entityReferenceNodes;
                break;
            }
            case ENTITY_NODE: {
                ++entityNodes;
                break;
            }
            case PROCESSING_INSTRUCTION_NODE: {
                ++piNodes;
                break;
            }
            case DOCUMENT_NODE: {
                ++documentNodes;
                break;
            }
            case DOCUMENT_TYPE_NODE: {
                ++docTypeNodes;
                break;
            }
            case DOCUMENT_FRAGMENT_NODE: {
                ++fragmentNodes;
                break;
            }
            case NOTATION_NODE: {
                ++notationNodes;
                break;
            }
            case XPATH_NAMESPACE_NODE: {
                ++xpathNSNodes;
                break;
            }
            case SHADOW_ROOT_NODE: {
                ++shadowRootNodes;
                break;
            }
        }
    }

    printf("Number of Nodes: %d\n\n", liveNodeSet.size());
    printf("Number of Nodes with RareData: %zu\n\n", nodesWithRareData);

    printf("NodeType distrubution:\n");
    printf("  Number of Element nodes: %zu\n", elementNodes);
    printf("  Number of Attribute nodes: %zu\n", attrNodes);
    printf("  Number of Text nodes: %zu\n", textNodes);
    printf("  Number of CDATASection nodes: %zu\n", cdataNodes);
    printf("  Number of Comment nodes: %zu\n", commentNodes);
    printf("  Number of EntityReference nodes: %zu\n", entityReferenceNodes);
    printf("  Number of Entity nodes: %zu\n", entityNodes);
    printf("  Number of ProcessingInstruction nodes: %zu\n", piNodes);
    printf("  Number of Document nodes: %zu\n", documentNodes);
    printf("  Number of DocumentType nodes: %zu\n", docTypeNodes);
    printf("  Number of DocumentFragment nodes: %zu\n", fragmentNodes);
    printf("  Number of Notation nodes: %zu\n", notationNodes);
    printf("  Number of XPathNS nodes: %zu\n", xpathNSNodes);
    printf("  Number of ShadowRoot nodes: %zu\n", shadowRootNodes);

    printf("Element tag name distibution:\n");
    for (HashMap<String, size_t>::iterator it = perTagCount.begin(); it != perTagCount.end(); ++it)
        printf("  Number of <%s> tags: %zu\n", it->first.utf8().data(), it->second);

    printf("Attribute Maps:\n");
    printf("  Number of Attributes (non-Node and Node): %zu [%zu]\n", attributes, sizeof(Attribute));
    printf("  Number of Attributes that are mapped: %zu\n", mappedAttributes);
    printf("  Number of Attributes with a StyleDeclaration: %zu\n", mappedAttributesWithStyleDecl);
    printf("  Number of Attributes with an Attr: %zu\n", attributesWithAttr);
    printf("  Number of NamedNodeMaps: %zu [%zu]\n", attrMaps, sizeof(NamedNodeMap));
#endif
}

#ifndef NDEBUG
static WTF::RefCountedLeakCounter nodeCounter("WebCoreNode");

static bool shouldIgnoreLeaks = false;
static HashSet<Node*> ignoreSet;
#endif

void Node::startIgnoringLeaks()
{
#ifndef NDEBUG
    shouldIgnoreLeaks = true;
#endif
}

void Node::stopIgnoringLeaks()
{
#ifndef NDEBUG
    shouldIgnoreLeaks = false;
#endif
}

Node::StyleChange Node::diff(const RenderStyle* s1, const RenderStyle* s2)
{
    // FIXME: The behavior of this function is just totally wrong.  It doesn't handle
    // explicit inheritance of non-inherited properties and so you end up not re-resolving
    // style in cases where you need to.
    StyleChange ch = NoInherit;
    EDisplay display1 = s1 ? s1->display() : NONE;
    bool fl1 = s1 && s1->hasPseudoStyle(FIRST_LETTER);
    EDisplay display2 = s2 ? s2->display() : NONE;
    bool fl2 = s2 && s2->hasPseudoStyle(FIRST_LETTER);
    
    // We just detach if a renderer acquires or loses a column-span, since spanning elements
    // typically won't contain much content.
    bool colSpan1 = s1 && s1->columnSpan();
    bool colSpan2 = s2 && s2->columnSpan();
    
    if (display1 != display2 || fl1 != fl2 || colSpan1 != colSpan2 || (s1 && s2 && !s1->contentDataEquivalent(s2)))
        ch = Detach;
    else if (!s1 || !s2)
        ch = Inherit;
    else if (*s1 == *s2)
        ch = NoChange;
    else if (s1->inheritedNotEqual(s2))
        ch = Inherit;
    
    // For nth-child and other positional rules, treat styles as different if they have
    // changed positionally in the DOM. This way subsequent sibling resolutions won't be confused
    // by the wrong child index and evaluate to incorrect results.
    if (ch == NoChange && s1->childIndex() != s2->childIndex())
        ch = NoInherit;

    // If the pseudoStyles have changed, we want any StyleChange that is not NoChange
    // because setStyle will do the right thing with anything else.
    if (ch == NoChange && s1->hasAnyPublicPseudoStyles()) {
        for (PseudoId pseudoId = FIRST_PUBLIC_PSEUDOID; ch == NoChange && pseudoId < FIRST_INTERNAL_PSEUDOID; pseudoId = static_cast<PseudoId>(pseudoId + 1)) {
            if (s1->hasPseudoStyle(pseudoId)) {
                RenderStyle* ps2 = s2->getCachedPseudoStyle(pseudoId);
                if (!ps2)
                    ch = NoInherit;
                else {
                    RenderStyle* ps1 = s1->getCachedPseudoStyle(pseudoId);
                    ch = ps1 && *ps1 == *ps2 ? NoChange : NoInherit;
                }
            }
        }
    }

    // When text-combine property has been changed, we need to prepare a separate renderer object.
    // When text-combine is on, we use RenderCombineText, otherwise RenderText.
    // https://bugs.webkit.org/show_bug.cgi?id=55069
    if ((s1 && s2) && (s1->hasTextCombine() != s2->hasTextCombine()))
        ch = Detach;

    return ch;
}

void Node::trackForDebugging()
{
#ifndef NDEBUG
    if (shouldIgnoreLeaks)
        ignoreSet.add(this);
    else
        nodeCounter.increment();
#endif

#if DUMP_NODE_STATISTICS
    liveNodeSet.add(this);
#endif
}

Node::~Node()
{
#ifndef NDEBUG
    HashSet<Node*>::iterator it = ignoreSet.find(this);
    if (it != ignoreSet.end())
        ignoreSet.remove(it);
    else
        nodeCounter.decrement();
#endif

#if DUMP_NODE_STATISTICS
    liveNodeSet.remove(this);
#endif

    if (!hasRareData())
        ASSERT(!NodeRareData::rareDataMap().contains(this));
    else {
        if (m_document && rareData()->nodeLists())
            m_document->removeNodeListCache();
        
        NodeRareData::NodeRareDataMap& dataMap = NodeRareData::rareDataMap();
        NodeRareData::NodeRareDataMap::iterator it = dataMap.find(this);
        ASSERT(it != dataMap.end());
        delete it->second;
        dataMap.remove(it);
    }

    if (renderer())
        detach();

    if (AXObjectCache::accessibilityEnabled() && m_document && m_document->axObjectCacheExists())
        m_document->axObjectCache()->removeNodeForUse(this);
    
    if (m_previous)
        m_previous->setNextSibling(0);
    if (m_next)
        m_next->setPreviousSibling(0);

    if (m_document)
        m_document->guardDeref();
}

#ifdef NDEBUG

static inline void setWillMoveToNewOwnerDocumentWasCalled(bool)
{
}

static inline void setDidMoveToNewOwnerDocumentWasCalled(bool)
{
}

#else
    
static bool willMoveToNewOwnerDocumentWasCalled;
static bool didMoveToNewOwnerDocumentWasCalled;

static void setWillMoveToNewOwnerDocumentWasCalled(bool wasCalled)
{
    willMoveToNewOwnerDocumentWasCalled = wasCalled;
}

static void setDidMoveToNewOwnerDocumentWasCalled(bool wasCalled)
{
    didMoveToNewOwnerDocumentWasCalled = wasCalled;
}
    
#endif
    
void Node::setDocument(Document* document)
{
    ASSERT(!inDocument() || m_document == document);
    if (inDocument() || m_document == document)
        return;

    document->guardRef();

    setWillMoveToNewOwnerDocumentWasCalled(false);
    willMoveToNewOwnerDocument();
    ASSERT(willMoveToNewOwnerDocumentWasCalled);

    if (hasRareData() && rareData()->nodeLists()) {
        if (m_document)
            m_document->removeNodeListCache();
        document->addNodeListCache();
    }

    if (m_document) {
        m_document->moveNodeIteratorsToNewDocument(this, document);
        m_document->guardDeref();
    }

    m_document = document;

    setDidMoveToNewOwnerDocumentWasCalled(false);
    didMoveToNewOwnerDocument();
    ASSERT(didMoveToNewOwnerDocumentWasCalled);
}

TreeScope* Node::treeScope() const
{
    // FIXME: Using m_document directly is not good -> see comment with document() in the header file.
    if (!hasRareData())
        return m_document;
    TreeScope* scope = rareData()->treeScope();
    return scope ? scope : m_document;
}

void Node::setTreeScopeRecursively(TreeScope* newTreeScope, bool includeRoot)
{
    ASSERT(this);
    ASSERT(!includeRoot || !isDocumentNode());
    ASSERT(newTreeScope);
    ASSERT(!m_deletionHasBegun);

    TreeScope* currentTreeScope = treeScope();
    if (currentTreeScope == newTreeScope)
        return;

    Document* currentDocument = document();
    Document* newDocument = newTreeScope->document();
    // 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.
    if (currentDocument && currentDocument != newDocument)
        currentDocument->incDOMTreeVersion();

    for (Node* node = includeRoot ? this : traverseNextNode(this); node; node = node->traverseNextNode(this)) {
        if (newTreeScope == newDocument) {
            if (node->hasRareData())
                node->rareData()->setTreeScope(0);
            // Setting the new document tree scope will be handled implicitly
            // by setDocument() below.
        } else
            node->ensureRareData()->setTreeScope(newTreeScope);

        node->setDocument(newDocument);

        if (!node->isElementNode())
            continue;
        if (ShadowRoot* shadowRoot = toElement(node)->shadowRoot()) {
            shadowRoot->setParentTreeScope(newTreeScope);
            if (currentDocument != newDocument)
                shadowRoot->setDocumentRecursively(newDocument);
        }
    }
}

NodeRareData* Node::rareData() const
{
    ASSERT(hasRareData());
    return NodeRareData::rareDataFromMap(this);
}

NodeRareData* Node::ensureRareData()
{
    if (hasRareData())
        return rareData();
    
    ASSERT(!NodeRareData::rareDataMap().contains(this));
    NodeRareData* data = createRareData();
    NodeRareData::rareDataMap().set(this, data);
    setFlag(HasRareDataFlag);
    return data;
}
    
NodeRareData* Node::createRareData()
{
    return new NodeRareData;
}

Element* Node::shadowHost() const
{
    return toElement(getFlag(IsShadowRootFlag) ? parent() : 0);
}

void Node::setShadowHost(Element* host)
{
    ASSERT(!parentNode() && !isSVGShadowRoot());
    if (host)
        setFlag(IsShadowRootFlag);
    else
        clearFlag(IsShadowRootFlag);

    setParent(host);
}

InputElement* Node::toInputElement()
{
    // If one of the below ASSERTs trigger, you are calling this function
    // directly or indirectly from a constructor or destructor of this object.
    // Don't do this!
    ASSERT(!(isHTMLElement() && hasTagName(inputTag)));
    return 0;
}

short Node::tabIndex() const
{
    return hasRareData() ? rareData()->tabIndex() : 0;
}
    
void Node::setTabIndexExplicitly(short i)
{
    ensureRareData()->setTabIndexExplicitly(i);
}

void Node::clearTabIndexExplicitly()
{
    ensureRareData()->clearTabIndexExplicitly();
}

String Node::nodeValue() const
{
    return String();
}

void Node::setNodeValue(const String& /*nodeValue*/, ExceptionCode& ec)
{
    // NO_MODIFICATION_ALLOWED_ERR: Raised when the node is readonly
    if (isReadOnlyNode()) {
        ec = NO_MODIFICATION_ALLOWED_ERR;
        return;
    }

    // By default, setting nodeValue has no effect.
}

PassRefPtr<NodeList> Node::childNodes()
{
    NodeRareData* data = ensureRareData();
    if (!data->nodeLists()) {
        data->setNodeLists(NodeListsNodeData::create());
        if (document())
            document()->addNodeListCache();
    }

    return ChildNodeList::create(this, data->nodeLists()->m_childNodeListCaches.get());
}

Node *Node::lastDescendant() const
{
    Node *n = const_cast<Node *>(this);
    while (n && n->lastChild())
        n = n->lastChild();
    return n;
}

Node* Node::firstDescendant() const
{
    Node *n = const_cast<Node *>(this);
    while (n && n->firstChild())
        n = n->firstChild();
    return n;
}

bool Node::insertBefore(PassRefPtr<Node> newChild, Node* refChild, ExceptionCode& ec, bool shouldLazyAttach)
{
    if (!isContainerNode()) {
        ec = HIERARCHY_REQUEST_ERR;
        return false;
    }
    return toContainerNode(this)->insertBefore(newChild, refChild, ec, shouldLazyAttach);
}

bool Node::replaceChild(PassRefPtr<Node> newChild, Node* oldChild, ExceptionCode& ec, bool shouldLazyAttach)
{
    if (!isContainerNode()) {
        ec = HIERARCHY_REQUEST_ERR;
        return false;
    }
    return toContainerNode(this)->replaceChild(newChild, oldChild, ec, shouldLazyAttach);
}

bool Node::removeChild(Node* oldChild, ExceptionCode& ec)
{
    if (!isContainerNode()) {
        ec = NOT_FOUND_ERR;
        return false;
    }
    return toContainerNode(this)->removeChild(oldChild, ec);
}

bool Node::appendChild(PassRefPtr<Node> newChild, ExceptionCode& ec, bool shouldLazyAttach)
{
    if (!isContainerNode()) {
        ec = HIERARCHY_REQUEST_ERR;
        return false;
    }
    return toContainerNode(this)->appendChild(newChild, ec, shouldLazyAttach);
}

void Node::remove(ExceptionCode& ec)
{
    if (ContainerNode* parent = parentNode())
        parent->removeChild(this, ec);
    else
        ec = HIERARCHY_REQUEST_ERR;
}

void Node::normalize()
{
    // Go through the subtree beneath us, normalizing all nodes. This means that
    // any two adjacent text nodes are merged and any empty text nodes are removed.

    RefPtr<Node> node = this;
    while (Node* firstChild = node->firstChild())
        node = firstChild;
    while (node) {
        NodeType type = node->nodeType();
        if (type == ELEMENT_NODE)
            static_cast<Element*>(node.get())->normalizeAttributes();

        if (node == this)
            break;

        if (type != TEXT_NODE) {
            node = node->traverseNextNodePostOrder();
            continue;
        }

        Text* text = static_cast<Text*>(node.get());

        // Remove empty text nodes.
        if (!text->length()) {
            // Care must be taken to get the next node before removing the current node.
            node = node->traverseNextNodePostOrder();
            ExceptionCode ec;
            text->remove(ec);
            continue;
        }

        // Merge text nodes.
        while (Node* nextSibling = node->nextSibling()) {
            if (nextSibling->nodeType() != TEXT_NODE)
                break;
            RefPtr<Text> nextText = static_cast<Text*>(nextSibling);

            // Remove empty text nodes.
            if (!nextText->length()) {
                ExceptionCode ec;
                nextText->remove(ec);
                continue;
            }

            // Both non-empty text nodes. Merge them.
            unsigned offset = text->length();
            ExceptionCode ec;
            text->appendData(nextText->data(), ec);
            document()->textNodesMerged(nextText.get(), offset);
            nextText->remove(ec);
        }

        node = node->traverseNextNodePostOrder();
    }
}

const AtomicString& Node::virtualPrefix() const
{
    // For nodes other than elements and attributes, the prefix is always null
    return nullAtom;
}

void Node::setPrefix(const AtomicString& /*prefix*/, ExceptionCode& ec)
{
    // The spec says that for nodes other than elements and attributes, prefix is always null.
    // It does not say what to do when the user tries to set the prefix on another type of
    // node, however Mozilla throws a NAMESPACE_ERR exception.
    ec = NAMESPACE_ERR;
}

const AtomicString& Node::virtualLocalName() const
{
    return nullAtom;
}

const AtomicString& Node::virtualNamespaceURI() const
{
    return nullAtom;
}

void Node::deprecatedParserAddChild(PassRefPtr<Node>)
{
}

bool Node::isContentEditable() const
{
    document()->updateLayoutIgnorePendingStylesheets();
    return rendererIsEditable(Editable);
}

bool Node::rendererIsEditable(EditableLevel editableLevel) const
{
    if (document()->frame() && document()->frame()->page() && document()->frame()->page()->isEditable())
        return true;

    // Ideally we'd call ASSERT(!needsStyleRecalc()) here, but
    // ContainerNode::setFocus() calls setNeedsStyleRecalc(), so the assertion
    // would fire in the middle of Document::setFocusedNode().

    for (const Node* node = this; node; node = node->parentNode()) {
        if ((node->isHTMLElement() || node->isDocumentNode()) && node->renderer()) {
            switch (node->renderer()->style()->userModify()) {
            case READ_ONLY:
                return false;
            case READ_WRITE:
                return true;
            case READ_WRITE_PLAINTEXT_ONLY:
                return editableLevel != RichlyEditable;
            }
            ASSERT_NOT_REACHED();
            return false;
        }
    }

    return false;
}

bool Node::shouldUseInputMethod() const
{
    return isContentEditable();
}

RenderBox* Node::renderBox() const
{
    return m_renderer && m_renderer->isBox() ? toRenderBox(m_renderer) : 0;
}

RenderBoxModelObject* Node::renderBoxModelObject() const
{
    return m_renderer && m_renderer->isBoxModelObject() ? toRenderBoxModelObject(m_renderer) : 0;
}

IntRect Node::getRect() const
{
    if (renderer())
        return renderer()->absoluteBoundingBoxRect(true);
    return IntRect();
}
    
IntRect Node::renderRect(bool* isReplaced)
{    
    RenderObject* hitRenderer = this->renderer();
    ASSERT(hitRenderer);
    RenderObject* renderer = hitRenderer;
    while (renderer && !renderer->isBody() && !renderer->isRoot()) {
        if (renderer->isRenderBlock() || renderer->isInlineBlockOrInlineTable() || renderer->isReplaced()) {
            *isReplaced = renderer->isReplaced();
            return renderer->absoluteBoundingBoxRect(true);
        }
        renderer = renderer->parent();
    }
    return IntRect();    
}

bool Node::hasNonEmptyBoundingBox() const
{
    // Before calling absoluteRects, check for the common case where the renderer
    // is non-empty, since this is a faster check and almost always returns true.
    RenderBoxModelObject* box = renderBoxModelObject();
    if (!box)
        return false;
    if (!box->borderBoundingBox().isEmpty())
        return true;

    Vector<IntRect> rects;
    FloatPoint absPos = renderer()->localToAbsolute();
    renderer()->absoluteRects(rects, absPos.x(), absPos.y());
    size_t n = rects.size();
    for (size_t i = 0; i < n; ++i)
        if (!rects[i].isEmpty())
            return true;

    return false;
}

inline static ShadowRoot* shadowRoot(Node* node)
{
    return node->isElementNode() ? toElement(node)->shadowRoot() : 0;
}

void Node::setDocumentRecursively(Document* newDocument)
{
    ASSERT(document() != newDocument);

    for (Node* node = this; node; node = node->traverseNextNode(this)) {
        node->setDocument(newDocument);
        if (!node->isElementNode())
            continue;
        if (ShadowRoot* shadow = shadowRoot(node))
            shadow->setDocumentRecursively(newDocument);
    }
}

inline void Node::setStyleChange(StyleChangeType changeType)
{
    m_nodeFlags = (m_nodeFlags & ~StyleChangeMask) | changeType;
}

inline void Node::markAncestorsWithChildNeedsStyleRecalc()
{
    for (ContainerNode* p = parentOrHostNode(); p && !p->childNeedsStyleRecalc(); p = p->parentOrHostNode())
        p->setChildNeedsStyleRecalc();

    if (document()->childNeedsStyleRecalc())
        document()->scheduleStyleRecalc();
}

void Node::refEventTarget()
{
    ref();
}

void Node::derefEventTarget()
{
    deref();
}

void Node::setNeedsStyleRecalc(StyleChangeType changeType)
{
    ASSERT(changeType != NoStyleChange);
    if (!attached()) // changed compared to what?
        return;

    StyleChangeType existingChangeType = styleChangeType();
    if (changeType > existingChangeType)
        setStyleChange(changeType);

    if (existingChangeType == NoStyleChange)
        markAncestorsWithChildNeedsStyleRecalc();
}

void Node::lazyAttach(ShouldSetAttached shouldSetAttached)
{
    for (Node* n = this; n; n = n->traverseNextNode(this)) {
        if (n->firstChild())
            n->setChildNeedsStyleRecalc();
        n->setStyleChange(FullStyleChange);
        if (shouldSetAttached == SetAttached)
            n->setAttached();
    }
    markAncestorsWithChildNeedsStyleRecalc();
}

void Node::setFocus(bool b)
{ 
    if (b || hasRareData())
        ensureRareData()->setFocused(b);
}

bool Node::rareDataFocused() const
{
    ASSERT(hasRareData());
    return rareData()->isFocused();
}

bool Node::supportsFocus() const
{
    return hasRareData() && rareData()->tabIndexSetExplicitly();
}
    
bool Node::isFocusable() const
{
    if (!inDocument() || !supportsFocus())
        return false;
    
    if (renderer())
        ASSERT(!renderer()->needsLayout());
    else
        // If the node is in a display:none tree it might say it needs style recalc but
        // the whole document is actually up to date.
        ASSERT(!document()->childNeedsStyleRecalc());
    
    // FIXME: Even if we are not visible, we might have a child that is visible.
    // Hyatt wants to fix that some day with a "has visible content" flag or the like.
    if (!renderer() || renderer()->style()->visibility() != VISIBLE)
        return false;

    return true;
}

bool Node::isKeyboardFocusable(KeyboardEvent*) const
{
    return isFocusable() && tabIndex() >= 0;
}

bool Node::isMouseFocusable() const
{
    return isFocusable();
}

unsigned Node::nodeIndex() const
{
    Node *_tempNode = previousSibling();
    unsigned count=0;
    for ( count=0; _tempNode; count++ )
        _tempNode = _tempNode->previousSibling();
    return count;
}

void Node::registerDynamicNodeList(DynamicNodeList* list)
{
    NodeRareData* data = ensureRareData();
    if (!data->nodeLists()) {
        data->setNodeLists(NodeListsNodeData::create());
        document()->addNodeListCache();
    } else if (!m_document || !m_document->hasNodeListCaches()) {
        // We haven't been receiving notifications while there were no registered lists, so the cache is invalid now.
        data->nodeLists()->invalidateCaches();
    }

    if (list->hasOwnCaches())
        data->nodeLists()->m_listsWithCaches.add(list);
}

void Node::unregisterDynamicNodeList(DynamicNodeList* list)
{
    ASSERT(rareData());
    ASSERT(rareData()->nodeLists());
    if (list->hasOwnCaches()) {
        NodeRareData* data = rareData();
        data->nodeLists()->m_listsWithCaches.remove(list);
        if (data->nodeLists()->isEmpty()) {
            data->clearNodeLists();
            if (document())
                document()->removeNodeListCache();
        }
    }
}

void Node::notifyLocalNodeListsAttributeChanged()
{
    if (!hasRareData())
        return;
    NodeRareData* data = rareData();
    if (!data->nodeLists())
        return;

    if (!isAttributeNode())
        data->nodeLists()->invalidateCachesThatDependOnAttributes();
    else
        data->nodeLists()->invalidateCaches();

    if (data->nodeLists()->isEmpty()) {
        data->clearNodeLists();
        document()->removeNodeListCache();
    }
}

void Node::notifyNodeListsAttributeChanged()
{
    for (Node *n = this; n; n = n->parentNode())
        n->notifyLocalNodeListsAttributeChanged();
}

void Node::notifyLocalNodeListsChildrenChanged()
{
    if (!hasRareData())
        return;
    NodeRareData* data = rareData();
    if (!data->nodeLists())
        return;

    data->nodeLists()->invalidateCaches();

    NodeListsNodeData::NodeListSet::iterator end = data->nodeLists()->m_listsWithCaches.end();
    for (NodeListsNodeData::NodeListSet::iterator i = data->nodeLists()->m_listsWithCaches.begin(); i != end; ++i)
        (*i)->invalidateCache();

    if (data->nodeLists()->isEmpty()) {
        data->clearNodeLists();
        document()->removeNodeListCache();
    }
}

void Node::notifyNodeListsChildrenChanged()
{
    for (Node* n = this; n; n = n->parentNode())
        n->notifyLocalNodeListsChildrenChanged();
}

void Node::notifyLocalNodeListsLabelChanged()
{
    if (!hasRareData())
        return;
    NodeRareData* data = rareData();
    if (!data->nodeLists())
        return;

    if (data->nodeLists()->m_labelsNodeListCache)
        data->nodeLists()->m_labelsNodeListCache->invalidateCache();
}

void Node::removeCachedClassNodeList(ClassNodeList* list, const String& className)
{
    ASSERT(rareData());
    ASSERT(rareData()->nodeLists());
    ASSERT_UNUSED(list, list->hasOwnCaches());

    NodeListsNodeData* data = rareData()->nodeLists();
    ASSERT_UNUSED(list, list == data->m_classNodeListCache.get(className));
    data->m_classNodeListCache.remove(className);
}

void Node::removeCachedNameNodeList(NameNodeList* list, const String& nodeName)
{
    ASSERT(rareData());
    ASSERT(rareData()->nodeLists());
    ASSERT_UNUSED(list, list->hasOwnCaches());

    NodeListsNodeData* data = rareData()->nodeLists();
    ASSERT_UNUSED(list, list == data->m_nameNodeListCache.get(nodeName));
    data->m_nameNodeListCache.remove(nodeName);
}

void Node::removeCachedTagNodeList(TagNodeList* list, const AtomicString& name)
{
    ASSERT(rareData());
    ASSERT(rareData()->nodeLists());
    ASSERT_UNUSED(list, list->hasOwnCaches());

    NodeListsNodeData* data = rareData()->nodeLists();
    ASSERT_UNUSED(list, list == data->m_tagNodeListCache.get(name.impl()));
    data->m_tagNodeListCache.remove(name.impl());
}

void Node::removeCachedTagNodeList(TagNodeList* list, const QualifiedName& name)
{
    ASSERT(rareData());
    ASSERT(rareData()->nodeLists());
    ASSERT_UNUSED(list, list->hasOwnCaches());

    NodeListsNodeData* data = rareData()->nodeLists();
    ASSERT_UNUSED(list, list == data->m_tagNodeListCacheNS.get(name.impl()));
    data->m_tagNodeListCacheNS.remove(name.impl());
}

void Node::removeCachedLabelsNodeList(DynamicNodeList* list)
{
    ASSERT(rareData());
    ASSERT(rareData()->nodeLists());
    ASSERT_UNUSED(list, list->hasOwnCaches());
    
    NodeListsNodeData* data = rareData()->nodeLists();
    data->m_labelsNodeListCache = 0;
}

Node* Node::traverseNextNode(const Node* stayWithin) const
{
    if (firstChild())
        return firstChild();
    if (this == stayWithin)
        return 0;
    if (nextSibling())
        return nextSibling();
    const Node *n = this;
    while (n && !n->nextSibling() && (!stayWithin || n->parentNode() != stayWithin))
        n = n->parentNode();
    if (n)
        return n->nextSibling();
    return 0;
}

Node* Node::traverseNextSibling(const Node* stayWithin) const
{
    if (this == stayWithin)
        return 0;
    if (nextSibling())
        return nextSibling();
    const Node *n = this;
    while (n && !n->nextSibling() && (!stayWithin || n->parentNode() != stayWithin))
        n = n->parentNode();
    if (n)
        return n->nextSibling();
    return 0;
}

Node* Node::traverseNextNodePostOrder() const
{
    Node* next = nextSibling();
    if (!next)
        return parentNode();
    while (Node* firstChild = next->firstChild())
        next = firstChild;
    return next;
}

Node* Node::traversePreviousNode(const Node* stayWithin) const
{
    if (this == stayWithin)
        return 0;
    if (previousSibling()) {
        Node *n = previousSibling();
        while (n->lastChild())
            n = n->lastChild();
        return n;
    }
    return parentNode();
}

Node* Node::traversePreviousNodePostOrder(const Node* stayWithin) const
{
    if (lastChild())
        return lastChild();
    if (this == stayWithin)
        return 0;
    if (previousSibling())
        return previousSibling();
    const Node *n = this;
    while (n && !n->previousSibling() && (!stayWithin || n->parentNode() != stayWithin))
        n = n->parentNode();
    if (n)
        return n->previousSibling();
    return 0;
}

Node* Node::traversePreviousSiblingPostOrder(const Node* stayWithin) const
{
    if (this == stayWithin)
        return 0;
    if (previousSibling())
        return previousSibling();
    const Node *n = this;
    while (n && !n->previousSibling() && (!stayWithin || n->parentNode() != stayWithin))
        n = n->parentNode();
    if (n)
        return n->previousSibling();
    return 0;
}

void Node::checkSetPrefix(const AtomicString& prefix, ExceptionCode& ec)
{
    // Perform error checking as required by spec for setting Node.prefix. Used by
    // Element::setPrefix() and Attr::setPrefix()

    // FIXME: Implement support for INVALID_CHARACTER_ERR: Raised if the specified prefix contains an illegal character.
    
    if (isReadOnlyNode()) {
        ec = NO_MODIFICATION_ALLOWED_ERR;
        return;
    }

    // FIXME: Raise NAMESPACE_ERR if prefix is malformed per the Namespaces in XML specification.

    const AtomicString& nodeNamespaceURI = namespaceURI();
    if ((nodeNamespaceURI.isEmpty() && !prefix.isEmpty())
        || (prefix == xmlAtom && nodeNamespaceURI != XMLNames::xmlNamespaceURI)) {
        ec = NAMESPACE_ERR;
        return;
    }
    // Attribute-specific checks are in Attr::setPrefix().
}

static bool isChildTypeAllowed(Node* newParent, Node* child)
{
    if (child->nodeType() != Node::DOCUMENT_FRAGMENT_NODE) {
        if (!newParent->childTypeAllowed(child->nodeType()))
            return false;
        return true;
    }
    
    for (Node *n = child->firstChild(); n; n = n->nextSibling()) {
        if (!newParent->childTypeAllowed(n->nodeType()))
            return false;
    }
    return true;
}

bool Node::canReplaceChild(Node* newChild, Node*)
{
    return isChildTypeAllowed(this, newChild);
}

static void checkAcceptChild(Node* newParent, Node* newChild, ExceptionCode& ec)
{
    // Not mentioned in spec: throw NOT_FOUND_ERR if newChild is null
    if (!newChild) {
        ec = NOT_FOUND_ERR;
        return;
    }
    
    if (newParent->isReadOnlyNode()) {
        ec = NO_MODIFICATION_ALLOWED_ERR;
        return;
    }

    if (newChild->inDocument() && newChild->nodeType() == Node::DOCUMENT_TYPE_NODE) {
        ec = HIERARCHY_REQUEST_ERR;
        return;
    }

    // HIERARCHY_REQUEST_ERR: Raised if this node is of a type that does not allow children of the type of the
    // newChild node, or if the node to append is one of this node's ancestors.

    if (newChild == newParent || newParent->isDescendantOf(newChild)) {
        ec = HIERARCHY_REQUEST_ERR;
        return;
    }
}

void Node::checkReplaceChild(Node* newChild, Node* oldChild, ExceptionCode& ec)
{
    if (!oldChild) {
        ec = NOT_FOUND_ERR;
        return;
    }

    checkAcceptChild(this, newChild, ec);
    if (ec)
        return;

    if (!canReplaceChild(newChild, oldChild)) {
        ec = HIERARCHY_REQUEST_ERR;
        return;
    }
}

void Node::checkAddChild(Node *newChild, ExceptionCode& ec)
{
    checkAcceptChild(this, newChild, ec);
    if (ec)
        return;
    
    if (!isChildTypeAllowed(this, newChild)) {
        ec = HIERARCHY_REQUEST_ERR;
        return;
    }
}

bool Node::isDescendantOf(const Node *other) const
{
    // Return true if other is an ancestor of this, otherwise false
    if (!other)
        return false;
    for (const ContainerNode* n = parentNode(); n; n = n->parentNode()) {
        if (n == other)
            return true;
    }
    return false;
}

bool Node::contains(const Node* node) const
{
    if (!node)
        return false;
    return this == node || node->isDescendantOf(this);
}

bool Node::containsIncludingShadowDOM(Node* node)
{
    if (!node)
        return false;
    for (Node* n = node; n; n = n->parentOrHostNode()) {
        if (n == this)
            return true;
    }
    return false;
}

void Node::attach()
{
    ASSERT(!attached());
    ASSERT(!renderer() || (renderer()->style() && renderer()->parent()));

    // FIXME: This is O(N^2) for the innerHTML case, where all children are replaced at once (and not attached).
    // If this node got a renderer it may be the previousRenderer() of sibling text nodes and thus affect the
    // result of Text::rendererIsNeeded() for those nodes.
    if (renderer()) {
        for (Node* next = nextSibling(); next; next = next->nextSibling()) {
            if (next->renderer())
                break;
            if (!next->attached())
                break;  // Assume this means none of the following siblings are attached.
            if (next->isTextNode())
                next->createRendererIfNeeded();
        }
    }

    setAttached();
    clearNeedsStyleRecalc();
}

void Node::willRemove()
{
}

void Node::detach()
{
    setFlag(InDetachFlag);

    if (renderer())
        renderer()->destroy();
    setRenderer(0);

    Document* doc = document();
    if (hovered())
        doc->hoveredNodeDetached(this);
    if (inActiveChain())
        doc->activeChainNodeDetached(this);

    clearFlag(IsActiveFlag);
    clearFlag(IsHoveredFlag);
    clearFlag(InActiveChainFlag);
    clearFlag(IsAttachedFlag);

    clearFlag(InDetachFlag);
}

RenderObject* Node::previousRenderer()
{
    // FIXME: We should have the same O(N^2) avoidance as nextRenderer does
    // however, when I tried adding it, several tests failed.
    for (Node* n = previousSibling(); n; n = n->previousSibling()) {
        if (n->renderer())
            return n->renderer();
    }
    return 0;
}

RenderObject* Node::nextRenderer()
{
    // Avoid an O(n^2) problem with this function by not checking for
    // nextRenderer() when the parent element hasn't attached yet.
    if (parentOrHostNode() && !parentOrHostNode()->attached())
        return 0;

    for (Node* n = nextSibling(); n; n = n->nextSibling()) {
        if (n->renderer())
            return n->renderer();
    }
    return 0;
}

// FIXME: This code is used by editing.  Seems like it could move over there and not pollute Node.
Node *Node::previousNodeConsideringAtomicNodes() const
{
    if (previousSibling()) {
        Node *n = previousSibling();
        while (!isAtomicNode(n) && n->lastChild())
            n = n->lastChild();
        return n;
    }
    else if (parentNode()) {
        return parentNode();
    }
    else {
        return 0;
    }
}

Node *Node::nextNodeConsideringAtomicNodes() const
{
    if (!isAtomicNode(this) && firstChild())
        return firstChild();
    if (nextSibling())
        return nextSibling();
    const Node *n = this;
    while (n && !n->nextSibling())
        n = n->parentNode();
    if (n)
        return n->nextSibling();
    return 0;
}

Node *Node::previousLeafNode() const
{
    Node *node = previousNodeConsideringAtomicNodes();
    while (node) {
        if (isAtomicNode(node))
            return node;
        node = node->previousNodeConsideringAtomicNodes();
    }
    return 0;
}

Node *Node::nextLeafNode() const
{
    Node *node = nextNodeConsideringAtomicNodes();
    while (node) {
        if (isAtomicNode(node))
            return node;
        node = node->nextNodeConsideringAtomicNodes();
    }
    return 0;
}


class NodeRendererFactory {
public:
    enum Type {
        NotFound,
        AsLightChild,
        AsShadowChild,
        AsContentChild
    };

    NodeRendererFactory(Node* node)
        : m_type(NotFound)
        , m_node(node)
        , m_visualParentShadowRoot(0)
    {
        m_parentNodeForRenderingAndStyle = findVisualParent();
    }
  
    ContainerNode* parentNodeForRenderingAndStyle() const { return m_parentNodeForRenderingAndStyle; }
    void createRendererIfNeeded();

private:
    Document* document() { return m_node->document(); }
    ContainerNode* findVisualParent();
    RenderObject* nextRenderer() const { return m_node->nextRenderer(); }
    RenderObject* createRendererAndStyle();
    bool shouldCreateRenderer() const;

    Type m_type;
    Node* m_node;
    ContainerNode* m_parentNodeForRenderingAndStyle;
    ShadowRoot* m_visualParentShadowRoot;
};

ContainerNode* NodeRendererFactory::findVisualParent()
{
    ContainerNode* parent = m_node->parentOrHostNode();
    if (!parent)
        return 0;

    if (parent->isShadowBoundary()) {
        m_type = AsShadowChild;
        return parent->shadowHost();
    }

    if (parent->isElementNode()) {
        m_visualParentShadowRoot = toElement(parent)->shadowRoot();
        if (m_visualParentShadowRoot) {
            if (ContainerNode* contentContainer = m_visualParentShadowRoot->contentContainerFor(m_node)) {
                m_type = AsContentChild;
                return NodeRendererFactory(contentContainer).parentNodeForRenderingAndStyle();
            }

            // FIXME: should be not found once light/shadow is mutual exclusive.
        }
    }

    m_type = AsLightChild;
    return parent;
}

bool NodeRendererFactory::shouldCreateRenderer() const
{
    ASSERT(m_parentNodeForRenderingAndStyle);

    RenderObject* parentRenderer = m_parentNodeForRenderingAndStyle->renderer();
    if (!parentRenderer)
        return false;

    if (m_type == AsLightChild) {
        // FIXME: Ignoring canHaveChildren() in a case of shadow children might be wrong.
        // See https://bugs.webkit.org/show_bug.cgi?id=52423
        if (!parentRenderer->canHaveChildren())
            return false;
    
        if (m_visualParentShadowRoot && !m_parentNodeForRenderingAndStyle->canHaveLightChildRendererWithShadow())
            return false;
    }

    if (!m_parentNodeForRenderingAndStyle->childShouldCreateRenderer(m_node))
        return false;

    return true;
}

RenderObject* NodeRendererFactory::createRendererAndStyle()
{
    ASSERT(!m_node->renderer());
    ASSERT(document()->shouldCreateRenderers());

    if (!shouldCreateRenderer())
        return 0;

    RefPtr<RenderStyle> style = m_node->styleForRenderer();
    if (!m_node->rendererIsNeeded(style.get()))
        return 0;

    RenderObject* newRenderer = m_node->createRenderer(document()->renderArena(), style.get());
    if (!newRenderer)
        return 0;

    if (!m_parentNodeForRenderingAndStyle->renderer()->isChildAllowed(newRenderer, style.get())) {
        newRenderer->destroy();
        return 0;
    }

    m_node->setRenderer(newRenderer);
    newRenderer->setAnimatableStyle(style.release()); // setAnimatableStyle() can depend on renderer() already being set.
    return newRenderer;
}

#if ENABLE(FULLSCREEN_API)
static RenderFullScreen* wrapWithRenderFullScreen(RenderObject* object, Document* document)
{
    RenderFullScreen* fullscreenRenderer = new (document->renderArena()) RenderFullScreen(document);
    fullscreenRenderer->setStyle(RenderFullScreen::createFullScreenStyle());
    // It's possible that we failed to create the new render and end up wrapping nothing.
    // We'll end up displaying a black screen, but Jer says this is expected.
    if (object)
        fullscreenRenderer->addChild(object);
    document->setFullScreenRenderer(fullscreenRenderer);
    return fullscreenRenderer;
}
#endif

void NodeRendererFactory::createRendererIfNeeded()
{
    if (!document()->shouldCreateRenderers())
        return;

    ASSERT(!m_node->renderer());

    RenderObject* newRenderer = createRendererAndStyle();

#if ENABLE(FULLSCREEN_API)
    if (document()->webkitIsFullScreen() && document()->webkitCurrentFullScreenElement() == m_node)
        newRenderer = wrapWithRenderFullScreen(newRenderer, document());
#endif

    if (!newRenderer)
        return;

    // Note: Adding newRenderer instead of renderer(). renderer() may be a child of newRenderer.
    m_parentNodeForRenderingAndStyle->renderer()->addChild(newRenderer, nextRenderer());
}

ContainerNode* Node::parentNodeForRenderingAndStyle()
{
    return NodeRendererFactory(this).parentNodeForRenderingAndStyle();
}

void Node::createRendererIfNeeded()
{
    NodeRendererFactory(this).createRendererIfNeeded();
}

PassRefPtr<RenderStyle> Node::styleForRenderer()
{
    if (isElementNode()) {
        bool allowSharing = true;
#if ENABLE(XHTMLMP)
        // noscript needs the display property protected - it's a special case
        allowSharing = localName() != HTMLNames::noscriptTag.localName();
#endif
        return document()->styleSelector()->styleForElement(static_cast<Element*>(this), 0, allowSharing);
    }
    return parentNode() && parentNode()->renderer() ? parentNode()->renderer()->style() : 0;
}

bool Node::rendererIsNeeded(RenderStyle *style)
{
    return (document()->documentElement() == this) || (style->display() != NONE);
}

RenderObject* Node::createRenderer(RenderArena*, RenderStyle*)
{
    ASSERT(false);
    return 0;
}
    
RenderStyle* Node::nonRendererRenderStyle() const
{ 
    return 0; 
}   

void Node::setRenderStyle(PassRefPtr<RenderStyle> s)
{
    if (m_renderer)
        m_renderer->setAnimatableStyle(s); 
}

RenderStyle* Node::virtualComputedStyle(PseudoId pseudoElementSpecifier)
{
    return parentOrHostNode() ? parentOrHostNode()->computedStyle(pseudoElementSpecifier) : 0;
}

int Node::maxCharacterOffset() const
{
    ASSERT_NOT_REACHED();
    return 0;
}

// FIXME: Shouldn't these functions be in the editing code?  Code that asks questions about HTML in the core DOM class
// is obviously misplaced.
bool Node::canStartSelection() const
{
    if (rendererIsEditable())
        return true;

    if (renderer()) {
        RenderStyle* style = renderer()->style();
        // We allow selections to begin within an element that has -webkit-user-select: none set,
        // but if the element is draggable then dragging should take priority over selection.
        if (style->userDrag() == DRAG_ELEMENT && style->userSelect() == SELECT_NONE)
            return false;
    }
    return parentOrHostNode() ? parentOrHostNode()->canStartSelection() : true;
}

#if ENABLE(SVG)
SVGUseElement* Node::svgShadowHost() const
{
    return isSVGShadowRoot() ? static_cast<SVGUseElement*>(parent()) : 0;
}
#endif

Node* Node::shadowAncestorNode()
{
#if ENABLE(SVG)
    // SVG elements living in a shadow tree only occur when <use> created them.
    // For these cases we do NOT want to return the shadowParentNode() here
    // but the actual shadow tree element - as main difference to the HTML forms
    // shadow tree concept. (This function _could_ be made virtual - opinions?)
    if (isSVGElement())
        return this;
#endif

    Node* root = shadowTreeRootNode();
    if (root)
        return root->shadowHost();
    return this;
}

Node* Node::shadowTreeRootNode()
{
    Node* root = this;
    while (root) {
        if (root->isShadowRoot() || root->isSVGShadowRoot())
            return root;
        root = root->parentNodeGuaranteedHostFree();
    }
    return 0;
}

bool Node::isInShadowTree()
{
    for (Node* n = this; n; n = n->parentNode())
        if (n->isShadowRoot())
            return true;
    return false;
}

Element* Node::parentOrHostElement() const
{
    ContainerNode* parent = parentOrHostNode();
    if (!parent)
        return 0;

    if (parent->isShadowRoot())
        parent = parent->shadowHost();

    if (!parent->isElementNode())
        return 0;

    return toElement(parent);
}


bool Node::isBlockFlow() const
{
    return renderer() && renderer()->isBlockFlow();
}

bool Node::isBlockFlowOrBlockTable() const
{
    return renderer() && (renderer()->isBlockFlow() || (renderer()->isTable() && !renderer()->isInline()));
}

Element *Node::enclosingBlockFlowElement() const
{…