WebCore/dom/Document.cpp - WebKit - Git at Google

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2008, 2009 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 "config.h"
 #include "Document.h"

 #include "AXObjectCache.h"
 #include "AnimationController.h"
 #include "Attr.h"
 #include "CDATASection.h"
 #include "CSSHelper.h"
 #include "CSSStyleSelector.h"
 #include "CSSStyleSheet.h"
 #include "CSSValueKeywords.h"
 #include "CString.h"
 #include "CachedCSSStyleSheet.h"
 #include "Comment.h"
 #include "Console.h"
 #include "CookieJar.h"
 #include "DOMImplementation.h"
 #include "DOMWindow.h"
 #include "DocLoader.h"
 #include "DocumentFragment.h"
 #include "DocumentLoader.h"
 #include "DocumentType.h"
 #include "EditingText.h"
 #include "Editor.h"
 #include "EntityReference.h"
 #include "Event.h"
 #include "EventHandler.h"
 #include "EventListener.h"
 #include "EventNames.h"
 #include "ExceptionCode.h"
 #include "FocusController.h"
 #include "Frame.h"
 #include "FrameLoader.h"
 #include "FrameTree.h"
 #include "FrameView.h"
 #include "HTMLAnchorElement.h"
 #include "HTMLBodyElement.h"
 #include "HTMLCanvasElement.h"
 #include "HTMLCollection.h"
 #include "HTMLDocument.h"
 #include "HTMLElementFactory.h"
 #include "HTMLFrameOwnerElement.h"
 #include "HTMLHeadElement.h"
 #include "HTMLInputElement.h"
 #include "HTMLLinkElement.h"
 #include "HTMLMapElement.h"
 #include "HTMLNameCollection.h"
 #include "HTMLNames.h"
 #include "HTMLParser.h"
 #include "HTMLStyleElement.h"
 #include "HTMLTitleElement.h"
 #include "HTTPParsers.h"
 #include "HistoryItem.h"
 #include "HitTestRequest.h"
 #include "HitTestResult.h"
 #include "ImageLoader.h"
 #include "InspectorController.h"
 #include "ScriptEventListener.h"
 #include "KeyboardEvent.h"
 #include "Logging.h"
 #include "MappedAttribute.h"
 #include "MessageEvent.h"
 #include "MouseEvent.h"
 #include "MouseEventWithHitTestResults.h"
 #include "MutationEvent.h"
 #include "NameNodeList.h"
 #include "NodeFilter.h"
 #include "NodeIterator.h"
 #include "NodeWithIndex.h"
 #include "OverflowEvent.h"
 #include "Page.h"
 #include "PlatformKeyboardEvent.h"
 #include "ProcessingInstruction.h"
 #include "ProgressEvent.h"
 #include "RegisteredEventListener.h"
 #include "RenderArena.h"
 #include "RenderTextControl.h"
 #include "RenderView.h"
 #include "RenderWidget.h"
 #include "ScriptController.h"
 #include "ScriptElement.h"
 #include "SecurityOrigin.h"
 #include "SegmentedString.h"
 #include "SelectionController.h"
 #include "Settings.h"
 #include "StyleSheetList.h"
 #include "TextEvent.h"
 #include "TextIterator.h"
 #include "TextResourceDecoder.h"
 #include "Timer.h"
 #include "TreeWalker.h"
 #include "UIEvent.h"
 #include "WebKitAnimationEvent.h"
 #include "WebKitTransitionEvent.h"
 #include "WheelEvent.h"
 #include "XMLHttpRequest.h"
 #include "XMLNames.h"
 #include "XMLTokenizer.h"
 #include <wtf/CurrentTime.h>
 #include <wtf/HashFunctions.h>
 #include <wtf/MainThread.h>
 #include <wtf/PassRefPtr.h>
 #include <wtf/StdLibExtras.h>

 #if ENABLE(DATABASE)
 #include "Database.h"
 #include "DatabaseThread.h"
 #endif

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

 #if ENABLE(XPATH)
 #include "XPathEvaluator.h"
 #include "XPathExpression.h"
 #include "XPathNSResolver.h"
 #include "XPathResult.h"
 #endif

 #if ENABLE(XSLT)
 #include "XSLTProcessor.h"
 #endif

 #if ENABLE(XBL)
 #include "XBLBindingManager.h"
 #endif

 #if ENABLE(SVG)
 #include "SVGDocumentExtensions.h"
 #include "SVGElementFactory.h"
 #include "SVGZoomEvent.h"
 #include "SVGStyleElement.h"
 #endif

 #if ENABLE(WML)
 #include "WMLDocument.h"
 #include "WMLElement.h"
 #include "WMLElementFactory.h"
 #include "WMLNames.h"
 #endif

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

 using namespace std;
 using namespace WTF;
 using namespace Unicode;

 namespace WebCore {

 using namespace HTMLNames;

 // #define INSTRUMENT_LAYOUT_SCHEDULING 1

 // This amount of time must have elapsed before we will even consider scheduling a layout without a delay.
 // FIXME: For faster machines this value can really be lowered to 200.  250 is adequate, but a little high
 // for dual G5s. :)
 static const int cLayoutScheduleThreshold = 250;

 // Use 1 to represent the document's default form.
 static HTMLFormElement* const defaultForm = reinterpret_cast<HTMLFormElement*>(1);

 // DOM Level 2 says (letters added):
 //
 // a) Name start characters must have one of the categories Ll, Lu, Lo, Lt, Nl.
 // b) Name characters other than Name-start characters must have one of the categories Mc, Me, Mn, Lm, or Nd.
 // c) Characters in the compatibility area (i.e. with character code greater than #xF900 and less than #xFFFE) are not allowed in XML names.
 // d) Characters which have a font or compatibility decomposition (i.e. those with a "compatibility formatting tag" in field 5 of the database -- marked by field 5 beginning with a "<") are not allowed.
 // e) The following characters are treated as name-start characters rather than name characters, because the property file classifies them as Alphabetic: [#x02BB-#x02C1], #x0559, #x06E5, #x06E6.
 // f) Characters #x20DD-#x20E0 are excluded (in accordance with Unicode, section 5.14).
 // g) Character #x00B7 is classified as an extender, because the property list so identifies it.
 // h) Character #x0387 is added as a name character, because #x00B7 is its canonical equivalent.
 // i) Characters ':' and '_' are allowed as name-start characters.
 // j) Characters '-' and '.' are allowed as name characters.
 //
 // It also contains complete tables. If we decide it's better, we could include those instead of the following code.

 static inline bool isValidNameStart(UChar32 c)
 {
     // rule (e) above
     if ((c >= 0x02BB && c <= 0x02C1) || c == 0x559 || c == 0x6E5 || c == 0x6E6)
         return true;

     // rule (i) above
     if (c == ':' || c == '_')
         return true;

     // rules (a) and (f) above
     const uint32_t nameStartMask = Letter_Lowercase | Letter_Uppercase | Letter_Other | Letter_Titlecase | Number_Letter;
     if (!(Unicode::category(c) & nameStartMask))
         return false;

     // rule (c) above
     if (c >= 0xF900 && c < 0xFFFE)
         return false;

     // rule (d) above
     DecompositionType decompType = decompositionType(c);
     if (decompType == DecompositionFont || decompType == DecompositionCompat)
         return false;

     return true;
 }

 static inline bool isValidNamePart(UChar32 c)
 {
     // rules (a), (e), and (i) above
     if (isValidNameStart(c))
         return true;

     // rules (g) and (h) above
     if (c == 0x00B7 || c == 0x0387)
         return true;

     // rule (j) above
     if (c == '-' || c == '.')
         return true;

     // rules (b) and (f) above
     const uint32_t otherNamePartMask = Mark_NonSpacing | Mark_Enclosing | Mark_SpacingCombining | Letter_Modifier | Number_DecimalDigit;
     if (!(Unicode::category(c) & otherNamePartMask))
         return false;

     // rule (c) above
     if (c >= 0xF900 && c < 0xFFFE)
         return false;

     // rule (d) above
     DecompositionType decompType = decompositionType(c);
     if (decompType == DecompositionFont || decompType == DecompositionCompat)
         return false;

     return true;
 }

 static Widget* widgetForNode(Node* focusedNode)
 {
     if (!focusedNode)
         return 0;
     RenderObject* renderer = focusedNode->renderer();
     if (!renderer || !renderer->isWidget())
         return 0;
     return static_cast<RenderWidget*>(renderer)->widget();
 }

 static bool acceptsEditingFocus(Node *node)
 {
     ASSERT(node);
     ASSERT(node->isContentEditable());

     Node *root = node->rootEditableElement();
     Frame* frame = node->document()->frame();
     if (!frame || !root)
         return false;

     return frame->editor()->shouldBeginEditing(rangeOfContents(root).get());
 }

 static bool disableRangeMutation(Page* page)
 {
 #if PLATFORM(MAC)
     // Disable Range mutation on document modifications in Tiger and Leopard Mail
     // See <rdar://problem/5865171>
     return page && (page->settings()->needsLeopardMailQuirks() || page->settings()->needsTigerMailQuirks());
 #else
     return false;
 #endif
 }

 static HashSet<Document*>* documentsThatNeedStyleRecalc = 0;

 Document::Document(Frame* frame, bool isXHTML)
     : ContainerNode(0)
     , m_domtree_version(0)
     , m_styleSheets(StyleSheetList::create(this))
     , m_styleRecalcTimer(this, &Document::styleRecalcTimerFired)
     , m_frameElementsShouldIgnoreScrolling(false)
     , m_title("")
     , m_titleSetExplicitly(false)
     , m_updateFocusAppearanceTimer(this, &Document::updateFocusAppearanceTimerFired)
     , m_executeScriptSoonTimer(this, &Document::executeScriptSoonTimerFired)
 #if ENABLE(XSLT)
     , m_transformSource(0)
 #endif
     , m_xmlVersion("1.0")
     , m_xmlStandalone(false)
 #if ENABLE(XBL)
     , m_bindingManager(new XBLBindingManager(this))
 #endif
     , m_savedRenderer(0)
     , m_secureForms(0)
     , m_designMode(inherit)
     , m_selfOnlyRefCount(0)
 #if ENABLE(SVG)
     , m_svgExtensions(0)
 #endif
 #if ENABLE(DASHBOARD_SUPPORT)
     , m_hasDashboardRegions(false)
     , m_dashboardRegionsDirty(false)
 #endif
     , m_accessKeyMapValid(false)
     , m_createRenderers(true)
     , m_inPageCache(false)
     , m_useSecureKeyboardEntryWhenActive(false)
     , m_isXHTML(isXHTML)
     , m_numNodeListCaches(0)
 #if ENABLE(DATABASE)
     , m_hasOpenDatabases(false)
 #endif
     , m_usingGeolocation(false)
 {
     m_document.resetSkippingRef(this);

     m_printing = false;

     m_ignoreAutofocus = false;

     m_frame = frame;
     m_renderArena = 0;

     m_axObjectCache = 0;

     m_docLoader = new DocLoader(this);

     visuallyOrdered = false;
     m_bParsing = false;
     m_tokenizer = 0;
     m_wellFormed = false;

     setParseMode(Strict);

     m_textColor = Color::black;
     m_listenerTypes = 0;
     m_inDocument = true;
     m_inStyleRecalc = false;
     m_closeAfterStyleRecalc = false;
     m_usesDescendantRules = false;
     m_usesSiblingRules = false;
     m_usesFirstLineRules = false;
     m_usesFirstLetterRules = false;
     m_usesBeforeAfterRules = false;
     m_gotoAnchorNeededAfterStylesheetsLoad = false;

     m_styleSelector = 0;
     m_didCalculateStyleSelector = false;
     m_pendingStylesheets = 0;
     m_ignorePendingStylesheets = false;
     m_hasNodesWithPlaceholderStyle = false;
     m_pendingSheetLayout = NoLayoutWithPendingSheets;

     m_cssTarget = 0;

     resetLinkColor();
     resetVisitedLinkColor();
     resetActiveLinkColor();

     m_processingLoadEvent = false;
     m_startTime = currentTime();
     m_overMinimumLayoutThreshold = false;

     initSecurityContext();
     initDNSPrefetch();

     static int docID = 0;
     m_docID = docID++;
 #if ENABLE(XHTMLMP)
     m_shouldProcessNoScriptElement = settings() && !settings()->isJavaScriptEnabled();
 #endif
 }

 void Document::removedLastRef()
 {
     ASSERT(!m_deletionHasBegun);
     if (m_selfOnlyRefCount) {
         // If removing a child removes the last self-only ref, we don't
         // want the document to be destructed until after
         // removeAllChildren returns, so we guard ourselves with an
         // extra self-only ref.

         DocPtr<Document> guard(this);

         // We must make sure not to be retaining any of our children through
         // these extra pointers or we will create a reference cycle.
         m_docType = 0;
         m_focusedNode = 0;
         m_hoverNode = 0;
         m_activeNode = 0;
         m_titleElement = 0;
         m_documentElement = 0;

         removeAllChildren();

         deleteAllValues(m_markers);
         m_markers.clear();

         delete m_tokenizer;
         m_tokenizer = 0;

         m_cssCanvasElements.clear();

 #ifndef NDEBUG
         m_inRemovedLastRefFunction = false;
 #endif
     } else {
 #ifndef NDEBUG
         m_deletionHasBegun = true;
 #endif
         delete this;
     }
 }

 Document::~Document()
 {
     ASSERT(!renderer());
     ASSERT(!m_inPageCache);
     ASSERT(!m_savedRenderer);
     ASSERT(m_ranges.isEmpty());
     ASSERT(!m_styleRecalcTimer.isActive());

     for (size_t i = 0; i < m_scriptsToExecuteSoon.size(); ++i)
         m_scriptsToExecuteSoon[i].first->element()->deref(); // Balances ref() in executeScriptSoon().

     removeAllEventListeners();

 #if USE(JSC)
     forgetAllDOMNodesForDocument(this);
 #endif

     delete m_tokenizer;
     m_document.resetSkippingRef(0);
     delete m_styleSelector;
     delete m_docLoader;

     if (m_renderArena) {
         delete m_renderArena;
         m_renderArena = 0;
     }

 #if ENABLE(XSLT)
     xmlFreeDoc((xmlDocPtr)m_transformSource);
 #endif

 #if ENABLE(XBL)
     delete m_bindingManager;
 #endif

     deleteAllValues(m_markers);

     clearAXObjectCache();

     m_decoder = 0;

     unsigned count = sizeof(m_nameCollectionInfo) / sizeof(m_nameCollectionInfo[0]);
     for (unsigned i = 0; i < count; i++)
         deleteAllValues(m_nameCollectionInfo[i]);

 #if ENABLE(DATABASE)
     if (m_databaseThread) {
         ASSERT(m_databaseThread->terminationRequested());
         m_databaseThread = 0;
     }
 #endif

     if (m_styleSheets)
         m_styleSheets->documentDestroyed();

     m_document = 0;
 }

 void Document::resetLinkColor()
 {
     m_linkColor = Color(0, 0, 238);
 }

 void Document::resetVisitedLinkColor()
 {
     m_visitedLinkColor = Color(85, 26, 139);
 }

 void Document::resetActiveLinkColor()
 {
     m_activeLinkColor.setNamedColor("red");
 }

 void Document::setDocType(PassRefPtr<DocumentType> docType)
 {
     // This should never be called more than once.
     // Note: This is not a public DOM method and can only be called by the parser.
     ASSERT(!m_docType || !docType);
     if (m_docType && docType)
         return;
     m_docType = docType;
     if (m_docType)
         m_docType->setDocument(this);
     determineParseMode();
 }

 DOMImplementation* Document::implementation() const
 {
     if (!m_implementation)
         m_implementation = DOMImplementation::create();
     return m_implementation.get();
 }

 void Document::childrenChanged(bool changedByParser, Node* beforeChange, Node* afterChange, int childCountDelta)
 {
     ContainerNode::childrenChanged(changedByParser, beforeChange, afterChange, childCountDelta);

     // Invalidate the document element we have cached in case it was replaced.
     m_documentElement = 0;
 }

 void Document::cacheDocumentElement() const
 {
     ASSERT(!m_documentElement);
     Node* n = firstChild();
     while (n && !n->isElementNode())
         n = n->nextSibling();
     m_documentElement = static_cast<Element*>(n);
 }

 PassRefPtr<Element> Document::createElement(const AtomicString& name, ExceptionCode& ec)
 {
     if (!isValidName(name)) {
         ec = INVALID_CHARACTER_ERR;
         return 0;
     }

     if (m_isXHTML)
         return HTMLElementFactory::createHTMLElement(QualifiedName(nullAtom, name, xhtmlNamespaceURI), this, 0, false);

     return createElement(QualifiedName(nullAtom, name, nullAtom), false);
 }

 PassRefPtr<DocumentFragment> Document::createDocumentFragment()
 {
     return new DocumentFragment(document());
 }

 PassRefPtr<Text> Document::createTextNode(const String& data)
 {
     return new Text(this, data);
 }

 PassRefPtr<Comment> Document::createComment(const String& data)
 {
     return new Comment(this, data);
 }

 PassRefPtr<CDATASection> Document::createCDATASection(const String& data, ExceptionCode& ec)
 {
     if (isHTMLDocument()) {
         ec = NOT_SUPPORTED_ERR;
         return 0;
     }
     return new CDATASection(this, data);
 }

 PassRefPtr<ProcessingInstruction> Document::createProcessingInstruction(const String& target, const String& data, ExceptionCode& ec)
 {
     if (!isValidName(target)) {
         ec = INVALID_CHARACTER_ERR;
         return 0;
     }
     if (isHTMLDocument()) {
         ec = NOT_SUPPORTED_ERR;
         return 0;
     }
     return new ProcessingInstruction(this, target, data);
 }

 PassRefPtr<EntityReference> Document::createEntityReference(const String& name, ExceptionCode& ec)
 {
     if (!isValidName(name)) {
         ec = INVALID_CHARACTER_ERR;
         return 0;
     }
     if (isHTMLDocument()) {
         ec = NOT_SUPPORTED_ERR;
         return 0;
     }
     return new EntityReference(this, name);
 }

 PassRefPtr<EditingText> Document::createEditingTextNode(const String& text)
 {
     return new EditingText(this, text);
 }

 PassRefPtr<CSSStyleDeclaration> Document::createCSSStyleDeclaration()
 {
     return CSSMutableStyleDeclaration::create();
 }

 PassRefPtr<Node> Document::importNode(Node* importedNode, bool deep, ExceptionCode& ec)
 {
     ec = 0;

     if (!importedNode
 #if ENABLE(SVG) && ENABLE(DASHBOARD_SUPPORT)
         || (importedNode->isSVGElement() && page() && page()->settings()->usesDashboardBackwardCompatibilityMode())
 #endif
         ) {
         ec = NOT_SUPPORTED_ERR;
         return 0;
     }

     switch (importedNode->nodeType()) {
         case TEXT_NODE:
             return createTextNode(importedNode->nodeValue());
         case CDATA_SECTION_NODE:
             return createCDATASection(importedNode->nodeValue(), ec);
         case ENTITY_REFERENCE_NODE:
             return createEntityReference(importedNode->nodeName(), ec);
         case PROCESSING_INSTRUCTION_NODE:
             return createProcessingInstruction(importedNode->nodeName(), importedNode->nodeValue(), ec);
         case COMMENT_NODE:
             return createComment(importedNode->nodeValue());
         case ELEMENT_NODE: {
             Element* oldElement = static_cast<Element*>(importedNode);
             RefPtr<Element> newElement = createElementNS(oldElement->namespaceURI(), oldElement->tagQName().toString(), ec);

             if (ec)
                 return 0;

             NamedNodeMap* attrs = oldElement->attributes(true);
             if (attrs) {
                 unsigned length = attrs->length();
                 for (unsigned i = 0; i < length; i++) {
                     Attribute* attr = attrs->attributeItem(i);
                     newElement->setAttribute(attr->name(), attr->value().impl(), ec);
                     if (ec)
                         return 0;
                 }
             }

             newElement->copyNonAttributeProperties(oldElement);

             if (deep) {
                 for (Node* oldChild = oldElement->firstChild(); oldChild; oldChild = oldChild->nextSibling()) {
                     RefPtr<Node> newChild = importNode(oldChild, true, ec);
                     if (ec)
                         return 0;
                     newElement->appendChild(newChild.release(), ec);
                     if (ec)
                         return 0;
                 }
             }

             return newElement.release();
         }
         case ATTRIBUTE_NODE: {
             RefPtr<Attr> newAttr = new Attr(0, this, static_cast<Attr*>(importedNode)->attr()->clone());
             newAttr->createTextChild();
             return newAttr.release();
         }
         case DOCUMENT_FRAGMENT_NODE: {
             DocumentFragment* oldFragment = static_cast<DocumentFragment*>(importedNode);
             RefPtr<DocumentFragment> newFragment = createDocumentFragment();
             if (deep) {
                 for (Node* oldChild = oldFragment->firstChild(); oldChild; oldChild = oldChild->nextSibling()) {
                     RefPtr<Node> newChild = importNode(oldChild, true, ec);
                     if (ec)
                         return 0;
                     newFragment->appendChild(newChild.release(), ec);
                     if (ec)
                         return 0;
                 }
             }

             return newFragment.release();
         }
         case ENTITY_NODE:
         case NOTATION_NODE:
             // FIXME: It should be possible to import these node types, however in DOM3 the DocumentType is readonly, so there isn't much sense in doing that.
             // Ability to add these imported nodes to a DocumentType will be considered for addition to a future release of the DOM.
         case DOCUMENT_NODE:
         case DOCUMENT_TYPE_NODE:
         case XPATH_NAMESPACE_NODE:
             break;
     }

     ec = NOT_SUPPORTED_ERR;
     return 0;
 }


 PassRefPtr<Node> Document::adoptNode(PassRefPtr<Node> source, ExceptionCode& ec)
 {
     if (!source) {
         ec = NOT_SUPPORTED_ERR;
         return 0;
     }

     if (source->isReadOnlyNode()) {
         ec = NO_MODIFICATION_ALLOWED_ERR;
         return 0;
     }

     switch (source->nodeType()) {
         case ENTITY_NODE:
         case NOTATION_NODE:
         case DOCUMENT_NODE:
         case DOCUMENT_TYPE_NODE:
         case XPATH_NAMESPACE_NODE:
             ec = NOT_SUPPORTED_ERR;
             return 0;
         case ATTRIBUTE_NODE: {
             Attr* attr = static_cast<Attr*>(source.get());
             if (attr->ownerElement())
                 attr->ownerElement()->removeAttributeNode(attr, ec);
             attr->setSpecified(true);
             break;
         }
         default:
             if (source->parentNode())
                 source->parentNode()->removeChild(source.get(), ec);
     }

     for (Node* node = source.get(); node; node = node->traverseNextNode(source.get()))
         node->setDocument(this);

     return source;
 }

 bool Document::hasPrefixNamespaceMismatch(const QualifiedName& qName)
 {
     DEFINE_STATIC_LOCAL(const AtomicString, xmlnsNamespaceURI, ("http://www.w3.org/2000/xmlns/"));
     DEFINE_STATIC_LOCAL(const AtomicString, xmlns, ("xmlns"));
     DEFINE_STATIC_LOCAL(const AtomicString, xml, ("xml"));

     // These checks are from DOM Core Level 2, createElementNS
     // http://www.w3.org/TR/DOM-Level-2-Core/core.html#ID-DocCrElNS
     if (!qName.prefix().isEmpty() && qName.namespaceURI().isNull()) // createElementNS(null, "html:div")
         return true;
     if (qName.prefix() == xml && qName.namespaceURI() != XMLNames::xmlNamespaceURI) // createElementNS("http://www.example.com", "xml:lang")
         return true;

     // Required by DOM Level 3 Core and unspecified by DOM Level 2 Core:
     // http://www.w3.org/TR/2004/REC-DOM-Level-3-Core-20040407/core.html#ID-DocCrElNS
     // createElementNS("http://www.w3.org/2000/xmlns/", "foo:bar"), createElementNS(null, "xmlns:bar")
     if ((qName.prefix() == xmlns && qName.namespaceURI() != xmlnsNamespaceURI) || (qName.prefix() != xmlns && qName.namespaceURI() == xmlnsNamespaceURI))
         return true;

     return false;
 }

 // FIXME: This should really be in a possible ElementFactory class
 PassRefPtr<Element> Document::createElement(const QualifiedName& qName, bool createdByParser)
 {
     RefPtr<Element> e;

     // FIXME: Use registered namespaces and look up in a hash to find the right factory.
     if (qName.namespaceURI() == xhtmlNamespaceURI)
         e = HTMLElementFactory::createHTMLElement(qName, this, 0, createdByParser);
 #if ENABLE(SVG)
     else if (qName.namespaceURI() == SVGNames::svgNamespaceURI)
         e = SVGElementFactory::createSVGElement(qName, this, createdByParser);
 #endif
 #if ENABLE(WML)
     else if (qName.namespaceURI() == WMLNames::wmlNamespaceURI)
         e = WMLElementFactory::createWMLElement(qName, this, createdByParser);
     else if (isWMLDocument())
         e = WMLElementFactory::createWMLElement(QualifiedName(nullAtom, qName.localName(), WMLNames::wmlNamespaceURI), this, createdByParser);
 #endif

     if (!e)
         e = new Element(qName, document());

     // <image> uses imgTag so we need a special rule.
 #if ENABLE(WML)
     if (!isWMLDocument())
 #endif
     ASSERT((qName.matches(imageTag) && e->tagQName().matches(imgTag) && e->tagQName().prefix() == qName.prefix()) || qName == e->tagQName());

     return e.release();
 }

 PassRefPtr<Element> Document::createElementNS(const String& namespaceURI, const String& qualifiedName, ExceptionCode& ec)
 {
     String prefix, localName;
     if (!parseQualifiedName(qualifiedName, prefix, localName, ec))
         return 0;

     QualifiedName qName(prefix, localName, namespaceURI);
     if (hasPrefixNamespaceMismatch(qName)) {
         ec = NAMESPACE_ERR;
         return 0;
     }

     return createElement(qName, false);
 }

 Element* Document::getElementById(const AtomicString& elementId) const
 {
     if (elementId.isEmpty())
         return 0;

     Element* element = m_elementsById.get(elementId.impl());
     if (element)
         return element;

     if (m_duplicateIds.contains(elementId.impl())) {
         // We know there's at least one node with this id, but we don't know what the first one is.
         for (Node *n = traverseNextNode(); n != 0; n = n->traverseNextNode()) {
             if (n->isElementNode()) {
                 element = static_cast<Element*>(n);
                 if (element->hasID() && element->getAttribute(idAttr) == elementId) {
                     m_duplicateIds.remove(elementId.impl());
                     m_elementsById.set(elementId.impl(), element);
                     return element;
                 }
             }
         }
         ASSERT_NOT_REACHED();
     }
     return 0;
 }

 String Document::readyState() const
 {
     if (Frame* f = frame()) {
         if (f->loader()->isComplete())
             return "complete";
         if (parsing())
             return "loading";
       return "loaded";
       // FIXME: What does "interactive" mean?
       // FIXME: Missing support for "uninitialized".
     }
     return String();
 }

 String Document::encoding() const
 {
     if (TextResourceDecoder* d = decoder())
         return d->encoding().domName();
     return String();
 }

 String Document::defaultCharset() const
 {
     if (Settings* settings = this->settings())
         return settings->defaultTextEncodingName();
     return String();
 }

 void Document::setCharset(const String& charset)
 {
     if (!decoder())
         return;
     decoder()->setEncoding(charset, TextResourceDecoder::UserChosenEncoding);
 }

 void Document::setXMLVersion(const String& version, ExceptionCode& ec)
 {
     if (!implementation()->hasFeature("XML", String())) {
         ec = NOT_SUPPORTED_ERR;
         return;
     }

     // FIXME: Also raise NOT_SUPPORTED_ERR if the version is set to a value that is not supported by this Document.

     m_xmlVersion = version;
 }

 void Document::setXMLStandalone(bool standalone, ExceptionCode& ec)
 {
     if (!implementation()->hasFeature("XML", String())) {
         ec = NOT_SUPPORTED_ERR;
         return;
     }

     m_xmlStandalone = standalone;
 }

 void Document::setDocumentURI(const String& uri)
 {
     m_documentURI = uri;
     updateBaseURL();
 }

 KURL Document::baseURI() const
 {
     return m_baseURL;
 }

 Element* Document::elementFromPoint(int x, int y) const
 {
     if (!renderer())
         return 0;

     HitTestRequest request(HitTestRequest::ReadOnly |
                            HitTestRequest::Active);

     float zoomFactor = frame() ? frame()->pageZoomFactor() : 1.0f;

     HitTestResult result(roundedIntPoint(FloatPoint(x * zoomFactor, y * zoomFactor)));
     renderView()->layer()->hitTest(request, result);

     Node* n = result.innerNode();
     while (n && !n->isElementNode())
         n = n->parentNode();
     if (n)
         n = n->shadowAncestorNode();
     return static_cast<Element*>(n);
 }

 void Document::addElementById(const AtomicString& elementId, Element* element)
 {
     typedef HashMap<AtomicStringImpl*, Element*>::iterator iterator;
     if (!m_duplicateIds.contains(elementId.impl())) {
         // Fast path. The ID is not already in m_duplicateIds, so we assume that it's
         // also not already in m_elementsById and do an add. If that add succeeds, we're done.
         pair<iterator, bool> addResult = m_elementsById.add(elementId.impl(), element);
         if (addResult.second)
             return;
         // The add failed, so this ID was already cached in m_elementsById.
         // There are multiple elements with this ID. Remove the m_elementsById
         // cache for this ID so getElementById searches for it next time it is called.
         m_elementsById.remove(addResult.first);
         m_duplicateIds.add(elementId.impl());
     } else {
         // There are multiple elements with this ID. If it exists, remove the m_elementsById
         // cache for this ID so getElementById searches for it next time it is called.
         iterator cachedItem = m_elementsById.find(elementId.impl());
         if (cachedItem != m_elementsById.end()) {
             m_elementsById.remove(cachedItem);
             m_duplicateIds.add(elementId.impl());
         }
     }
     m_duplicateIds.add(elementId.impl());
 }

 void Document::removeElementById(const AtomicString& elementId, Element* element)
 {
     if (m_elementsById.get(elementId.impl()) == element)
         m_elementsById.remove(elementId.impl());
     else
         m_duplicateIds.remove(elementId.impl());
 }

 Element* Document::getElementByAccessKey(const String& key) const
 {
     if (key.isEmpty())
         return 0;
     if (!m_accessKeyMapValid) {
         for (Node* n = firstChild(); n; n = n->traverseNextNode()) {
             if (!n->isElementNode())
                 continue;
             Element* element = static_cast<Element*>(n);
             const AtomicString& accessKey = element->getAttribute(accesskeyAttr);
             if (!accessKey.isEmpty())
                 m_elementsByAccessKey.set(accessKey.impl(), element);
         }
         m_accessKeyMapValid = true;
     }
     return m_elementsByAccessKey.get(key.impl());
 }

 void Document::updateTitle()
 {
     if (Frame* f = frame())
         f->loader()->setTitle(m_title);
 }

 void Document::setTitle(const String& title, Element* titleElement)
 {
     if (!titleElement) {
         // Title set by JavaScript -- overrides any title elements.
         m_titleSetExplicitly = true;
         if (!isHTMLDocument())
             m_titleElement = 0;
         else if (!m_titleElement) {
             if (HTMLElement* headElement = head()) {
                 m_titleElement = createElement(titleTag, false);
                 ExceptionCode ec = 0;
                 headElement->appendChild(m_titleElement, ec);
                 ASSERT(!ec);
             }
         }
     } else if (titleElement != m_titleElement) {
         if (m_titleElement || m_titleSetExplicitly)
             // Only allow the first title element to change the title -- others have no effect.
             return;
         m_titleElement = titleElement;
     }

     if (m_title == title)
         return;

     m_title = title;
     updateTitle();

     if (m_titleSetExplicitly && m_titleElement && m_titleElement->hasTagName(titleTag))
         static_cast<HTMLTitleElement*>(m_titleElement.get())->setText(m_title);
 }

 void Document::removeTitle(Element* titleElement)
 {
     if (m_titleElement != titleElement)
         return;

     m_titleElement = 0;
     m_titleSetExplicitly = false;

     // Update title based on first title element in the head, if one exists.
     if (HTMLElement* headElement = head()) {
         for (Node* e = headElement->firstChild(); e; e = e->nextSibling())
             if (e->hasTagName(titleTag)) {
                 HTMLTitleElement* titleElement = static_cast<HTMLTitleElement*>(e);
                 setTitle(titleElement->text(), titleElement);
                 break;
             }
     }

     if (!m_titleElement && !m_title.isEmpty()) {
         m_title = "";
         updateTitle();
     }
 }

 String Document::nodeName() const
 {
     return "#document";
 }

 Node::NodeType Document::nodeType() const
 {
     return DOCUMENT_NODE;
 }

 FrameView* Document::view() const
 {
     return m_frame ? m_frame->view() : 0;
 }

 Page* Document::page() const
 {
     return m_frame ? m_frame->page() : 0;
 }

 Settings* Document::settings() const
 {
     return m_frame ? m_frame->settings() : 0;
 }

 PassRefPtr<Range> Document::createRange()
 {
     return Range::create(this);
 }

 PassRefPtr<NodeIterator> Document::createNodeIterator(Node* root, unsigned whatToShow,
     PassRefPtr<NodeFilter> filter, bool expandEntityReferences, ExceptionCode& ec)
 {
     if (!root) {
         ec = NOT_SUPPORTED_ERR;
         return 0;
     }
     return NodeIterator::create(root, whatToShow, filter, expandEntityReferences);
 }

 PassRefPtr<TreeWalker> Document::createTreeWalker(Node *root, unsigned whatToShow,
     PassRefPtr<NodeFilter> filter, bool expandEntityReferences, ExceptionCode& ec)
 {
     if (!root) {
         ec = NOT_SUPPORTED_ERR;
         return 0;
     }
     return TreeWalker::create(root, whatToShow, filter, expandEntityReferences);
 }

 void Document::scheduleStyleRecalc()
 {
     if (m_styleRecalcTimer.isActive() || inPageCache())
         return;

     ASSERT(childNeedsStyleRecalc());

     if (!documentsThatNeedStyleRecalc)
         documentsThatNeedStyleRecalc = new HashSet<Document*>;
     documentsThatNeedStyleRecalc->add(this);

     // FIXME: Why on earth is this here? This is clearly misplaced.
     if (m_accessKeyMapValid) {
         m_accessKeyMapValid = false;
         m_elementsByAccessKey.clear();
     }

     m_styleRecalcTimer.startOneShot(0);
 }

 void Document::unscheduleStyleRecalc()
 {
     ASSERT(!childNeedsStyleRecalc());

     if (documentsThatNeedStyleRecalc)
         documentsThatNeedStyleRecalc->remove(this);

     m_styleRecalcTimer.stop();
 }

 void Document::styleRecalcTimerFired(Timer<Document>*)
 {
     updateStyleIfNeeded();
 }

 void Document::recalcStyle(StyleChange change)
 {
     // we should not enter style recalc while painting
     if (view() && view()->isPainting()) {
         ASSERT(!view()->isPainting());
         return;
     }

     if (m_inStyleRecalc)
         return; // Guard against re-entrancy. -dwh

     m_inStyleRecalc = true;
     suspendPostAttachCallbacks();
     RenderWidget::suspendWidgetHierarchyUpdates();
     if (view())
         view()->pauseScheduledEvents();

     ASSERT(!renderer() || renderArena());
     if (!renderer() || !renderArena())
         goto bail_out;

     if (change == Force) {
         // style selector may set this again during recalc
         m_hasNodesWithPlaceholderStyle = false;

         RefPtr<RenderStyle> documentStyle = RenderStyle::create();
         documentStyle->setDisplay(BLOCK);
         documentStyle->setVisuallyOrdered(visuallyOrdered);
         documentStyle->setZoom(frame()->pageZoomFactor());
         m_styleSelector->setStyle(documentStyle);

         FontDescription fontDescription;
         fontDescription.setUsePrinterFont(printing());
         if (Settings* settings = this->settings()) {
             fontDescription.setRenderingMode(settings->fontRenderingMode());
             if (printing() && !settings->shouldPrintBackgrounds())
                 documentStyle->setForceBackgroundsToWhite(true);
             const AtomicString& stdfont = settings->standardFontFamily();
             if (!stdfont.isEmpty()) {
                 fontDescription.firstFamily().setFamily(stdfont);
                 fontDescription.firstFamily().appendFamily(0);
             }
             fontDescription.setKeywordSize(CSSValueMedium - CSSValueXxSmall + 1);
             m_styleSelector->setFontSize(fontDescription, m_styleSelector->fontSizeForKeyword(CSSValueMedium, inCompatMode(), false));
         }

         documentStyle->setFontDescription(fontDescription);
         documentStyle->font().update(m_styleSelector->fontSelector());
         if (inCompatMode())
             documentStyle->setHtmlHacks(true); // enable html specific rendering tricks

         StyleChange ch = diff(documentStyle.get(), renderer()->style());
         if (renderer() && ch != NoChange)
             renderer()->setStyle(documentStyle.release());
     }

     for (Node* n = firstChild(); n; n = n->nextSibling())
         if (change >= Inherit || n->childNeedsStyleRecalc() || n->needsStyleRecalc())
             n->recalcStyle(change);

 #if USE(ACCELERATED_COMPOSITING)
     if (view()) {
         bool layoutPending = view()->layoutPending() || renderer()->needsLayout();
         // If we didn't update compositing layers because of layout(), we need to do so here.
         if (!layoutPending)
             view()->updateCompositingLayers();
     }
 #endif

 bail_out:
     setNeedsStyleRecalc(NoStyleChange);
     setChildNeedsStyleRecalc(false);
     unscheduleStyleRecalc();

     if (view())
         view()->resumeScheduledEvents();
     RenderWidget::resumeWidgetHierarchyUpdates();
     resumePostAttachCallbacks();
     m_inStyleRecalc = false;

     // If we wanted to call implicitClose() during recalcStyle, do so now that we're finished.
     if (m_closeAfterStyleRecalc) {
         m_closeAfterStyleRecalc = false;
         implicitClose();
     }
 }

 void Document::updateStyleIfNeeded()
 {
     if (!childNeedsStyleRecalc() || inPageCache())
         return;

     if (m_frame)
         m_frame->animation()->beginAnimationUpdate();

     recalcStyle(NoChange);

     // Tell the animation controller that updateStyleIfNeeded is finished and it can do any post-processing
     if (m_frame)
         m_frame->animation()->endAnimationUpdate();
 }

 void Document::updateStyleForAllDocuments()
 {
     if (!documentsThatNeedStyleRecalc)
         return;

     while (documentsThatNeedStyleRecalc->size()) {
         HashSet<Document*>::iterator it = documentsThatNeedStyleRecalc->begin();
         Document* doc = *it;
         documentsThatNeedStyleRecalc->remove(doc);
         ASSERT(doc->childNeedsStyleRecalc() && !doc->inPageCache());
         doc->updateStyleIfNeeded();
     }
 }

 void Document::updateLayout()
 {
     if (Element* oe = ownerElement())
         oe->document()->updateLayout();

     updateStyleIfNeeded();

     // Only do a layout if changes have occurred that make it necessary.
     FrameView* v = view();
     if (v && renderer() && (v->layoutPending() || renderer()->needsLayout()))
         v->layout();
 }

 // FIXME: This is a bad idea and needs to be removed eventually.
 // Other browsers load stylesheets before they continue parsing the web page.
 // Since we don't, we can run JavaScript code that needs answers before the
 // stylesheets are loaded. Doing a layout ignoring the pending stylesheets
 // lets us get reasonable answers. The long term solution to this problem is
 // to instead suspend JavaScript execution.
 void Document::updateLayoutIgnorePendingStylesheets()
 {
     bool oldIgnore = m_ignorePendingStylesheets;

     if (!haveStylesheetsLoaded()) {
         m_ignorePendingStylesheets = true;
         // FIXME: We are willing to attempt to suppress painting with outdated style info only once.  Our assumption is that it would be
         // dangerous to try to stop it a second time, after page content has already been loaded and displayed
         // with accurate style information.  (Our suppression involves blanking the whole page at the
         // moment.  If it were more refined, we might be able to do something better.)
         // It's worth noting though that this entire method is a hack, since what we really want to do is
         // suspend JS instead of doing a layout with inaccurate information.
         if (body() && !body()->renderer() && m_pendingSheetLayout == NoLayoutWithPendingSheets) {
             m_pendingSheetLayout = DidLayoutWithPendingSheets;
             updateStyleSelector();
         } else if (m_hasNodesWithPlaceholderStyle)
             // If new nodes have been added or style recalc has been done with style sheets still pending, some nodes
             // may not have had their real style calculated yet. Normally this gets cleaned when style sheets arrive
             // but here we need up-to-date style immediatly.
             recalcStyle(Force);
     }

     updateLayout();

     m_ignorePendingStylesheets = oldIgnore;
 }

 void Document::attach()
 {
     ASSERT(!attached());
     ASSERT(!m_inPageCache);
     ASSERT(!m_axObjectCache);

     if (!m_renderArena)
         m_renderArena = new RenderArena();

     // Create the rendering tree
     setRenderer(new (m_renderArena) RenderView(this, view()));
 #if USE(ACCELERATED_COMPOSITING)
     renderView()->didMoveOnscreen();
 #endif

     if (!m_styleSelector) {
         bool matchAuthorAndUserStyles = true;
         if (Settings* docSettings = settings())
             matchAuthorAndUserStyles = docSettings->authorAndUserStylesEnabled();
         m_styleSelector = new CSSStyleSelector(this, userStyleSheet(), m_styleSheets.get(), m_mappedElementSheet.get(), !inCompatMode(), matchAuthorAndUserStyles);
     }

     recalcStyle(Force);

     RenderObject* render = renderer();
     setRenderer(0);

     ContainerNode::attach();

     setRenderer(render);
 }

 void Document::detach()
 {
     ASSERT(attached());
     ASSERT(!m_inPageCache);

     clearAXObjectCache();
     stopActiveDOMObjects();

     RenderObject* render = renderer();

     // Send out documentWillBecomeInactive() notifications to registered elements,
     // in order to stop media elements
     documentWillBecomeInactive();

     if (m_frame) {
         FrameView* view = m_frame->view();
         if (view)
             view->detachCustomScrollbars();
     }

     // indicate destruction mode,  i.e. attached() but renderer == 0
     setRenderer(0);

     m_hoverNode = 0;
     m_focusedNode = 0;
     m_activeNode = 0;

     ContainerNode::detach();

     unscheduleStyleRecalc();

     if (render)
         render->destroy();

     // This is required, as our Frame might delete itself as soon as it detaches
     // us. However, this violates Node::detach() symantics, as it's never
     // possible to re-attach. Eventually Document::detach() should be renamed,
     // or this setting of the frame to 0 could be made explicit in each of the
     // callers of Document::detach().
     m_frame = 0;

     if (m_renderArena) {
         delete m_renderArena;
         m_renderArena = 0;
     }
 }

 void Document::removeAllEventListeners()
 {
     if (DOMWindow* domWindow = this->domWindow())
         domWindow->removeAllEventListeners();
     removeAllDisconnectedNodeEventListeners();
     for (Node* node = this; node; node = node->traverseNextNode())
         node->removeAllEventListeners();
 }

 void Document::registerDisconnectedNodeWithEventListeners(Node* node)
 {
     m_disconnectedNodesWithEventListeners.add(node);
 }

 void Document::unregisterDisconnectedNodeWithEventListeners(Node* node)
 {
     m_disconnectedNodesWithEventListeners.remove(node);
 }

 void Document::removeAllDisconnectedNodeEventListeners()
 {
     HashSet<Node*>::iterator end = m_disconnectedNodesWithEventListeners.end();
     for (HashSet<Node*>::iterator i = m_disconnectedNodesWithEventListeners.begin(); i != end; ++i)
         (*i)->removeAllEventListeners();
     m_disconnectedNodesWithEventListeners.clear();
 }

 RenderView* Document::renderView() const
 {
     return toRenderView(renderer());
 }

 void Document::clearAXObjectCache()
 {
     // clear cache in top document
     if (m_axObjectCache) {
         delete m_axObjectCache;
         m_axObjectCache = 0;
         return;
     }

     // ask the top-level document to clear its cache
     Document* doc = topDocument();
     if (doc != this)
         doc->clearAXObjectCache();
 }

 AXObjectCache* Document::axObjectCache() const
 {
     // The only document that actually has a AXObjectCache is the top-level
     // document.  This is because we need to be able to get from any WebCoreAXObject
     // to any other WebCoreAXObject on the same page.  Using a single cache allows
     // lookups across nested webareas (i.e. multiple documents).

     if (m_axObjectCache) {
         // return already known top-level cache
         if (!ownerElement())
             return m_axObjectCache;

         // In some pages with frames, the cache is created before the sub-webarea is
         // inserted into the tree.  Here, we catch that case and just toss the old
         // cache and start over.
         // NOTE: This recovery may no longer be needed. I have been unable to trigger
         // it again. See rdar://5794454
         // FIXME: Can this be fixed when inserting the subframe instead of now?
         // FIXME: If this function was called to get the cache in order to remove
         // an AXObject, we are now deleting the cache as a whole and returning a
         // new empty cache that does not contain the AXObject! That should actually
         // be OK. I am concerned about other cases like this where accessing the
         // cache blows away the AXObject being operated on.
         delete m_axObjectCache;
         m_axObjectCache = 0;
     }

     // ask the top-level document for its cache
     Document* doc = topDocument();
     if (doc != this)
         return doc->axObjectCache();

     // this is the top-level document, so install a new cache
     m_axObjectCache = new AXObjectCache(this);
     return m_axObjectCache;
 }

 void Document::setVisuallyOrdered()
 {
     visuallyOrdered = true;
     if (renderer())
         renderer()->style()->setVisuallyOrdered(true);
 }

 Tokenizer* Document::createTokenizer()
 {
     // FIXME: this should probably pass the frame instead
     return new XMLTokenizer(this, view());
 }

 void Document::open(Document* ownerDocument)
 {
     if (ownerDocument) {
         setURL(ownerDocument->url());
         m_cookieURL = ownerDocument->cookieURL();
         ScriptExecutionContext::setSecurityOrigin(ownerDocument->securityOrigin());
     }

     if (m_frame) {
         if (m_frame->loader()->isLoadingMainResource() || (tokenizer() && tokenizer()->executingScript()))
             return;

         if (m_frame->loader()->state() == FrameStateProvisional)
             m_frame->loader()->stopAllLoaders();
     }

     implicitOpen();

     if (m_frame)
         m_frame->loader()->didExplicitOpen();
 }

 void Document::cancelParsing()
 {
     if (m_tokenizer) {
         // We have to clear the tokenizer to avoid possibly triggering
         // the onload handler when closing as a side effect of a cancel-style
         // change, such as opening a new document or closing the window while
         // still parsing
         delete m_tokenizer;
         m_tokenizer = 0;
         close();
     }
 }

 void Document::implicitOpen()
 {
     cancelParsing();

     clear();
     m_tokenizer = createTokenizer();
     setParsing(true);

     if (m_frame)
         m_tokenizer->setXSSAuditor(m_frame->script()->xssAuditor());

     // If we reload, the animation controller sticks around and has
     // a stale animation time. We need to update it here.
     if (m_frame && m_frame->animation())
         m_frame->animation()->beginAnimationUpdate();
 }

 HTMLElement* Document::body() const
 {
     Node* de = documentElement();
     if (!de)
         return 0;

     // try to prefer a FRAMESET element over BODY
     Node* body = 0;
     for (Node* i = de->firstChild(); i; i = i->nextSibling()) {
         if (i->hasTagName(framesetTag))
             return static_cast<HTMLElement*>(i);

         if (i->hasTagName(bodyTag) && !body)
             body = i;
     }
     return static_cast<HTMLElement*>(body);
 }

 void Document::setBody(PassRefPtr<HTMLElement> newBody, ExceptionCode& ec)
 {
     if (!newBody || !documentElement()) {
         ec = HIERARCHY_REQUEST_ERR;
         return;
     }

     HTMLElement* b = body();
     if (!b)
         documentElement()->appendChild(newBody, ec);
     else
         documentElement()->replaceChild(newBody, b, ec);
 }

 HTMLHeadElement* Document::head()
 {
     Node* de = documentElement();
     if (!de)
         return 0;

     for (Node* e = de->firstChild(); e; e = e->nextSibling())
         if (e->hasTagName(headTag))
             return static_cast<HTMLHeadElement*>(e);

     return 0;
 }

 void Document::close()
 {
     Frame* frame = this->frame();
     if (frame) {
         // This code calls implicitClose() if all loading has completed.
         FrameLoader* frameLoader = frame->loader();
         frameLoader->endIfNotLoadingMainResource();
         frameLoader->checkCompleted();
     } else {
         // Because we have no frame, we don't know if all loading has completed,
         // so we just call implicitClose() immediately. FIXME: This might fire
         // the load event prematurely <http://bugs.webkit.org/show_bug.cgi?id=14568>.
         implicitClose();
     }
 }

 void Document::implicitClose()
 {
     // If we're in the middle of recalcStyle, we need to defer the close until the style information is accurate and all elements are re-attached.
     if (m_inStyleRecalc) {
         m_closeAfterStyleRecalc = true;
         return;
     }

     bool wasLocationChangePending = frame() && frame()->loader()->isScheduledLocationChangePending();
     bool doload = !parsing() && m_tokenizer && !m_processingLoadEvent && !wasLocationChangePending;

     if (!doload)
         return;

     m_processingLoadEvent = true;

     m_wellFormed = m_tokenizer && m_tokenizer->wellFormed();

     // We have to clear the tokenizer, in case someone document.write()s from the
     // onLoad event handler, as in Radar 3206524.
     delete m_tokenizer;
     m_tokenizer = 0;

     // Parser should have picked up all preloads by now
     m_docLoader->clearPreloads();

     // Create a head and a body if we don't have those yet (e.g. for about:blank).
     if (!this->body() && isHTMLDocument()) {
         if (Node* documentElement = this->documentElement()) {
             ExceptionCode ec = 0;

             // The implicit <head> isn't expected in older versions of Mail - <rdar://problem/6863795>
             if (!head() && shouldCreateImplicitHead(this)) {
                 documentElement->appendChild(new HTMLHeadElement(headTag, this), ec);
                 ASSERT(!ec);
             }
             documentElement->appendChild(new HTMLBodyElement(bodyTag, this), ec);
             ASSERT(!ec);
         }
     }

     // FIXME: We kick off the icon loader when the Document is done parsing.
     // There are earlier opportunities we could start it:
     //  -When the <head> finishes parsing
     //  -When any new HTMLLinkElement is inserted into the document
     // But those add a dynamic component to the favicon that has UI
     // ramifications, and we need to decide what is the Right Thing To Do(tm)
     Frame* f = frame();
     if (f)
         f->loader()->startIconLoader();

     // Resume the animations (or start them)
     if (f)
         f->animation()->resumeAnimations(this);

     ImageLoader::dispatchPendingLoadEvents();
     dispatchLoadEvent();
     if (f)
         f->loader()->handledOnloadEvents();
 #ifdef INSTRUMENT_LAYOUT_SCHEDULING
     if (!ownerElement())
         printf("onload fired at %d\n", elapsedTime());
 #endif

     m_processingLoadEvent = false;

     // An event handler may have removed the frame
     if (!frame())
         return;

     // Make sure both the initial layout and reflow happen after the onload
     // fires. This will improve onload scores, and other browsers do it.
     // If they wanna cheat, we can too. -dwh

     if (frame()->loader()->isScheduledLocationChangePending() && elapsedTime() < cLayoutScheduleThreshold) {
         // Just bail out. Before or during the onload we were shifted to another page.
         // The old i-Bench suite does this. When this happens don't bother painting or laying out.
         view()->unscheduleRelayout();
         return;
     }

     frame()->loader()->checkCallImplicitClose();
     RenderObject* renderObject = renderer();

     // We used to force a synchronous display and flush here.  This really isn't
     // necessary and can in fact be actively harmful if pages are loading at a rate of > 60fps
     // (if your platform is syncing flushes and limiting them to 60fps).
     m_overMinimumLayoutThreshold = true;
     if (!ownerElement() || (ownerElement()->renderer() && !ownerElement()->renderer()->needsLayout())) {
         updateStyleIfNeeded();

         // Always do a layout after loading if needed.
         if (view() && renderObject && (!renderObject->firstChild() || renderObject->needsLayout()))
             view()->layout();
     }

 #if PLATFORM(MAC)
     if (f && renderObject && this == topDocument() && AXObjectCache::accessibilityEnabled())
         // The AX cache may have been cleared at this point, but we need to make sure it contains an
         // AX object to send the notification to. getOrCreate will make sure that an valid AX object
         // exists in the cache (we ignore the return value because we don't need it here). This is
         // only safe to call when a layout is not in progress, so it can not be used in postNotification.
         axObjectCache()->getOrCreate(renderObject);
         axObjectCache()->postNotification(renderObject, "AXLoadComplete", true);
 #endif

 #if ENABLE(SVG)
     // FIXME: Officially, time 0 is when the outermost <svg> receives its
     // SVGLoad event, but we don't implement those yet.  This is close enough
     // for now.  In some cases we should have fired earlier.
     if (svgExtensions())
         accessSVGExtensions()->startAnimations();
 #endif
 }

 void Document::setParsing(bool b)
 {
     m_bParsing = b;
     if (!m_bParsing && view())
         view()->scheduleRelayout();

 #ifdef INSTRUMENT_LAYOUT_SCHEDULING
     if (!ownerElement() && !m_bParsing)
         printf("Parsing finished at %d\n", elapsedTime());
 #endif
 }

 bool Document::shouldScheduleLayout()
 {
     // This function will only be called when FrameView thinks a layout is needed.
     // This enforces a couple extra rules.
     //
     //    (a) Only schedule a layout once the stylesheets are loaded.
     //    (b) Only schedule layout once we have a body element.

     return (haveStylesheetsLoaded() && body()) ||
         (documentElement() && !documentElement()->hasTagName(htmlTag));
 }

 int Document::minimumLayoutDelay()
 {
     if (m_overMinimumLayoutThreshold)
         return 0;

     int elapsed = elapsedTime();
     m_overMinimumLayoutThreshold = elapsed > cLayoutScheduleThreshold;

     // We'll want to schedule the timer to fire at the minimum layout threshold.
     return max(0, cLayoutScheduleThreshold - elapsed);
 }

 int Document::elapsedTime() const
 {
     return static_cast<int>((currentTime() - m_startTime) * 1000);
 }

 void Document::write(const SegmentedString& text, Document* ownerDocument)
 {
 #ifdef INSTRUMENT_LAYOUT_SCHEDULING
     if (!ownerElement())
         printf("Beginning a document.write at %d\n", elapsedTime());
 #endif

     if (!m_tokenizer)
         open(ownerDocument);

     ASSERT(m_tokenizer);
     m_tokenizer->write(text, false);

 #ifdef INSTRUMENT_LAYOUT_SCHEDULING
     if (!ownerElement())
         printf("Ending a document.write at %d\n", elapsedTime());
 #endif
 }

 void Document::write(const String& text, Document* ownerDocument)
 {
     write(SegmentedString(text), ownerDocument);
 }

 void Document::writeln(const String& text, Document* ownerDocument)
 {
     write(text, ownerDocument);
     write("\n", ownerDocument);
 }

 void Document::finishParsing()
 {
 #ifdef INSTRUMENT_LAYOUT_SCHEDULING
     if (!ownerElement())
         printf("Received all data at %d\n", elapsedTime());
 #endif

     // Let the tokenizer go through as much data as it can.  There will be three possible outcomes after
     // finish() is called:
     // (1) All remaining data is parsed, document isn't loaded yet
     // (2) All remaining data is parsed, document is loaded, tokenizer gets deleted
     // (3) Data is still remaining to be parsed.
     if (m_tokenizer)
         m_tokenizer->finish();
 }

 void Document::clear()
 {
     delete m_tokenizer;
     m_tokenizer = 0;

     removeChildren();
     if (DOMWindow* domWindow = this->domWindow())
         domWindow->removeAllEventListeners();
 }

 const KURL& Document::virtualURL() const
 {
     return m_url;
 }

 KURL Document::virtualCompleteURL(const String& url) const
 {
     return completeURL(url);
 }

 void Document::setURL(const KURL& url)
 {
     const KURL& newURL = url.isEmpty() ? blankURL() : url;
     if (newURL == m_url)
         return;

     m_url = newURL;
     m_documentURI = m_url.string();
     updateBaseURL();
 }

 void Document::setBaseElementURL(const KURL& baseElementURL)
 {
     m_baseElementURL = baseElementURL;
     updateBaseURL();
 }

 void Document::updateBaseURL()
 {
     // DOM 3 Core: When the Document supports the feature "HTML" [DOM Level 2 HTML], the base URI is computed using
     // first the value of the href attribute of the HTML BASE element if any, and the value of the documentURI attribute
     // from the Document interface otherwise.
     if (m_baseElementURL.isEmpty()) {
         // The documentURI attribute is an arbitrary string. DOM 3 Core does not specify how it should be resolved,
         // so we use a null base URL.
         m_baseURL = KURL(KURL(), documentURI());
     } else
         m_baseURL = m_baseElementURL;
     if (!m_baseURL.isValid())
         m_baseURL = KURL();

     if (m_elemSheet)
         m_elemSheet->setHref(m_baseURL.string());
     if (m_mappedElementSheet)
         m_mappedElementSheet->setHref(m_baseURL.string());
 }

 String Document::userAgent(const KURL& url) const
 {
     return frame() ? frame()->loader()->userAgent(url) : String();
 }

 void Document::setCSSStyleSheet(const String& url, const String& charset, const CachedCSSStyleSheet* sheet)
 {
     m_sheet = CSSStyleSheet::create(this, url, charset);
     m_sheet->parseString(sheet->sheetText());

     updateStyleSelector();
 }

 #if FRAME_LOADS_USER_STYLESHEET
 void Document::setUserStyleSheet(const String& sheet)
 {
     if (m_usersheet != sheet) {
         m_usersheet = sheet;
         updateStyleSelector();
     }
 }
 #endif

 String Document::userStyleSheet() const
 {
 #if FRAME_LOADS_USER_STYLESHEET
     return m_usersheet;
 #else
     Page* page = this->page();
     if (!page)
         return String();
     return page->userStyleSheet();
 #endif
 }

 CSSStyleSheet* Document::elementSheet()
 {
     if (!m_elemSheet)
         m_elemSheet = CSSStyleSheet::create(this, m_baseURL.string());
     return m_elemSheet.get();
 }

 CSSStyleSheet* Document::mappedElementSheet()
 {
     if (!m_mappedElementSheet)
         m_mappedElementSheet = CSSStyleSheet::create(this, m_baseURL.string());
     return m_mappedElementSheet.get();
 }

 static Node* nextNodeWithExactTabIndex(Node* start, int tabIndex, KeyboardEvent* event)
 {
     // Search is inclusive of start
     for (Node* n = start; n; n = n->traverseNextNode())
         if (n->isKeyboardFocusable(event) && n->tabIndex() == tabIndex)
             return n;

     return 0;
 }

 static Node* previousNodeWithExactTabIndex(Node* start, int tabIndex, KeyboardEvent* event)
 {
     // Search is inclusive of start
     for (Node* n = start; n; n = n->traversePreviousNode())
         if (n->isKeyboardFocusable(event) && n->tabIndex() == tabIndex)
             return n;

     return 0;
 }

 static Node* nextNodeWithGreaterTabIndex(Node* start, int tabIndex, KeyboardEvent* event)
 {
     // Search is inclusive of start
     int winningTabIndex = SHRT_MAX + 1;
     Node* winner = 0;
     for (Node* n = start; n; n = n->traverseNextNode())
         if (n->isKeyboardFocusable(event) && n->tabIndex() > tabIndex && n->tabIndex() < winningTabIndex) {
             winner = n;
             winningTabIndex = n->tabIndex();
         }

     return winner;
 }

 static Node* previousNodeWithLowerTabIndex(Node* start, int tabIndex, KeyboardEvent* event)
 {
     // Search is inclusive of start
     int winningTabIndex = 0;
     Node* winner = 0;
     for (Node* n = start; n; n = n->traversePreviousNode())
         if (n->isKeyboardFocusable(event) && n->tabIndex() < tabIndex && n->tabIndex() > winningTabIndex) {
             winner = n;
             winningTabIndex = n->tabIndex();
         }

     return winner;
 }

 Node* Document::nextFocusableNode(Node* start, KeyboardEvent* event)
 {
     if (start) {
         // If a node is excluded from the normal tabbing cycle, the next focusable node is determined by tree order
         if (start->tabIndex() < 0) {
             for (Node* n = start->traverseNextNode(); n; n = n->traverseNextNode())
                 if (n->isKeyboardFocusable(event) && n->tabIndex() >= 0)
                     return n;
         }

         // First try to find a node with the same tabindex as start that comes after start in the document.
         if (Node* winner = nextNodeWithExactTabIndex(start->traverseNextNode(), start->tabIndex(), event))
             return winner;

         if (start->tabIndex() == 0)
             // We've reached the last node in the document with a tabindex of 0. This is the end of the tabbing order.
             return 0;
     }

     // Look for the first node in the document that:
     // 1) has the lowest tabindex that is higher than start's tabindex (or 0, if start is null), and
     // 2) comes first in the document, if there's a tie.
     if (Node* winner = nextNodeWithGreaterTabIndex(this, start ? start->tabIndex() : 0, event))
         return winner;

     // There are no nodes with a tabindex greater than start's tabindex,
     // so find the first node with a tabindex of 0.
     return nextNodeWithExactTabIndex(this, 0, event);
 }

 Node* Document::previousFocusableNode(Node* start, KeyboardEvent* event)
 {
     Node* last;
     for (last = this; last->lastChild(); last = last->lastChild())
         ; // Empty loop.

     // First try to find the last node in the document that comes before start and has the same tabindex as start.
     // If start is null, find the last node in the document with a tabindex of 0.
     Node* startingNode;
     int startingTabIndex;
     if (start) {
         startingNode = start->traversePreviousNode();
         startingTabIndex = start->tabIndex();
     } else {
         startingNode = last;
         startingTabIndex = 0;
     }

     // However, if a node is excluded from the normal tabbing cycle, the previous focusable node is determined by tree order
     if (startingTabIndex < 0) {
         for (Node* n = startingNode; n; n = n->traversePreviousNode())
             if (n->isKeyboardFocusable(event) && n->tabIndex() >= 0)
                 return n;
     }

     if (Node* winner = previousNodeWithExactTabIndex(startingNode, startingTabIndex, event))
         return winner;

     // There are no nodes before start with the same tabindex as start, so look for a node that:
     // 1) has the highest non-zero tabindex (that is less than start's tabindex), and
     // 2) comes last in the document, if there's a tie.
     startingTabIndex = (start && start->tabIndex()) ? start->tabIndex() : SHRT_MAX;
     return previousNodeWithLowerTabIndex(last, startingTabIndex, event);
 }

 int Document::nodeAbsIndex(Node *node)
 {
     ASSERT(node->document() == this);

     int absIndex = 0;
     for (Node *n = node; n && n != this; n = n->traversePreviousNode())
         absIndex++;
     return absIndex;
 }

 Node *Document::nodeWithAbsIndex(int absIndex)
 {
     Node *n = this;
     for (int i = 0; n && (i < absIndex); i++) {
         n = n->traverseNextNode();
     }
     return n;
 }

 void Document::processHttpEquiv(const String& equiv, const String& content)
 {
     ASSERT(!equiv.isNull() && !content.isNull());

     Frame* frame = this->frame();

     if (equalIgnoringCase(equiv, "default-style")) {
         // The preferred style set has been overridden as per section
         // 14.3.2 of the HTML4.0 specification.  We need to update the
         // sheet used variable and then update our style selector.
         // For more info, see the test at:
         // http://www.hixie.ch/tests/evil/css/import/main/preferred.html
         // -dwh
         m_selectedStylesheetSet = content;
         m_preferredStylesheetSet = content;
         updateStyleSelector();
     } else if (equalIgnoringCase(equiv, "refresh")) {
         double delay;
         String url;
         if (frame && parseHTTPRefresh(content, true, delay, url)) {
             if (url.isEmpty())
                 url = frame->loader()->url().string();
             else
                 url = completeURL(url).string();
             frame->loader()->scheduleHTTPRedirection(delay, url);
         }
     } else if (equalIgnoringCase(equiv, "set-cookie")) {
         // FIXME: make setCookie work on XML documents too; e.g. in case of <html:meta .....>
         if (isHTMLDocument())
             static_cast<HTMLDocument*>(this)->setCookie(content);
     } else if (equalIgnoringCase(equiv, "content-language"))
         setContentLanguage(content);
     else if (equalIgnoringCase(equiv, "x-dns-prefetch-control"))
         parseDNSPrefetchControlHeader(content);
     else if (equalIgnoringCase(equiv, "x-frame-options")) {
         FrameLoader* frameLoader = frame->loader();
         if (frameLoader->shouldInterruptLoadForXFrameOptions(content, url())) {
             frameLoader->stopAllLoaders();
             frameLoader->scheduleHTTPRedirection(0, blankURL());
         }
     }
 }

 MouseEventWithHitTestResults Document::prepareMouseEvent(const HitTestRequest& request, const IntPoint& documentPoint, const PlatformMouseEvent& event)
 {
     ASSERT(!renderer() || renderer()->isRenderView());

     if (!renderer())
         return MouseEventWithHitTestResults(event, HitTestResult(IntPoint()));

     HitTestResult result(documentPoint);
     renderView()->layer()->hitTest(request, result);

     if (!request.readOnly())
         updateStyleIfNeeded();

     return MouseEventWithHitTestResults(event, result);
 }

 // DOM Section 1.1.1
 bool Document::childTypeAllowed(NodeType type)
 {
     switch (type) {
         case ATTRIBUTE_NODE:
         case CDATA_SECTION_NODE:
         case DOCUMENT_FRAGMENT_NODE:
         case DOCUMENT_NODE:
         case ENTITY_NODE:
         case ENTITY_REFERENCE_NODE:
         case NOTATION_NODE:
         case TEXT_NODE:
         case XPATH_NAMESPACE_NODE:
             return false;
         case COMMENT_NODE:
         case PROCESSING_INSTRUCTION_NODE:
             return true;
         case DOCUMENT_TYPE_NODE:
         case ELEMENT_NODE:
             // Documents may contain no more than one of each of these.
             // (One Element and one DocumentType.)
             for (Node* c = firstChild(); c; c = c->nextSibling())
                 if (c->nodeType() == type)
                     return false;
             return true;
     }
     return false;
 }

 bool Document::canReplaceChild(Node* newChild, Node* oldChild)
 {
     if (!oldChild)
         // ContainerNode::replaceChild will raise a NOT_FOUND_ERR.
         return true;

     if (oldChild->nodeType() == newChild->nodeType())
         return true;

     int numDoctypes = 0;
     int numElements = 0;

     // First, check how many doctypes and elements we have, not counting
     // the child we're about to remove.
     for (Node* c = firstChild(); c; c = c->nextSibling()) {
         if (c == oldChild)
             continue;

         switch (c->nodeType()) {
             case DOCUMENT_TYPE_NODE:
                 numDoctypes++;
                 break;
             case ELEMENT_NODE:
                 numElements++;
                 break;
             default:
                 break;
         }
     }

     // Then, see how many doctypes and elements might be added by the new child.
     if (newChild->nodeType() == DOCUMENT_FRAGMENT_NODE) {
         for (Node* c = firstChild(); c; c = c->nextSibling()) {
             switch (c->nodeType()) {
                 case ATTRIBUTE_NODE:
                 case CDATA_SECTION_NODE:
                 case DOCUMENT_FRAGMENT_NODE:
                 case DOCUMENT_NODE:
                 case ENTITY_NODE:
                 case ENTITY_REFERENCE_NODE:
                 case NOTATION_NODE:
                 case TEXT_NODE:
                 case XPATH_NAMESPACE_NODE:
                     return false;
                 case COMMENT_NODE:
                 case PROCESSING_INSTRUCTION_NODE:
                     break;
                 case DOCUMENT_TYPE_NODE:
                     numDoctypes++;
                     break;
                 case ELEMENT_NODE:
                     numElements++;
                     break;
             }
         }
     } else {
         switch (newChild->nodeType()) {
             case ATTRIBUTE_NODE:
             case CDATA_SECTION_NODE:
             case DOCUMENT_FRAGMENT_NODE:
             case DOCUMENT_NODE:
             case ENTITY_NODE:
             case ENTITY_REFERENCE_NODE:
             case NOTATION_NODE:
             case TEXT_NODE:
             case XPATH_NAMESPACE_NODE:
                 return false;
             case COMMENT_NODE:
             case PROCESSING_INSTRUCTION_NODE:
                 return true;
             case DOCUMENT_TYPE_NODE:
                 numDoctypes++;
                 break;
             case ELEMENT_NODE:
                 numElements++;
                 break;
         }
     }

     if (numElements > 1 || numDoctypes > 1)
         return false;

     return true;
 }

 PassRefPtr<Node> Document::cloneNode(bool /*deep*/)
 {
     // Spec says cloning Document nodes is "implementation dependent"
     // so we do not support it...
     return 0;
 }

 StyleSheetList* Document::styleSheets()
 {
     return m_styleSheets.get();
 }

 String Document::preferredStylesheetSet() const
 {
     return m_preferredStylesheetSet;
 }

 String Document::selectedStylesheetSet() const
 {
     return m_selectedStylesheetSet;
 }

 void Document::setSelectedStylesheetSet(const String& aString)
 {
     m_selectedStylesheetSet = aString;
     updateStyleSelector();
     if (renderer())
         renderer()->repaint();
 }

 // This method is called whenever a top-level stylesheet has finished loading.
 void Document::removePendingSheet()
 {
     // Make sure we knew this sheet was pending, and that our count isn't out of sync.
     ASSERT(m_pendingStylesheets > 0);

     m_pendingStylesheets--;

 #ifdef INSTRUMENT_LAYOUT_SCHEDULING
     if (!ownerElement())
         printf("Stylesheet loaded at time %d. %d stylesheets still remain.\n", elapsedTime(), m_pendingStylesheets);
 #endif

     updateStyleSelector();

     if (!m_pendingStylesheets && m_tokenizer)
         m_tokenizer->executeScriptsWaitingForStylesheets();

     if (!m_pendingStylesheets && m_gotoAnchorNeededAfterStylesheetsLoad && m_frame)
         m_frame->loader()->gotoAnchor();
 }

 void Document::updateStyleSelector()
 {
     // Don't bother updating, since we haven't loaded all our style info yet
     // and haven't calculated the style selector for the first time.
     if (!m_didCalculateStyleSelector && !haveStylesheetsLoaded())
         return;

     if (didLayoutWithPendingStylesheets() && m_pendingStylesheets <= 0) {
         m_pendingSheetLayout = IgnoreLayoutWithPendingSheets;
         if (renderer())
             renderer()->repaint();
     }

 #ifdef INSTRUMENT_LAYOUT_SCHEDULING
     if (!ownerElement())
         printf("Beginning update of style selector at time %d.\n", elapsedTime());
 #endif

     recalcStyleSelector();
     recalcStyle(Force);

 #ifdef INSTRUMENT_LAYOUT_SCHEDULING
     if (!ownerElement())
         printf("Finished update of style selector at time %d\n", elapsedTime());
 #endif

     if (renderer()) {
         renderer()->setNeedsLayoutAndPrefWidthsRecalc();
         if (view())
             view()->scheduleRelayout();
     }
 }

 void Document::addStyleSheetCandidateNode(Node* node, bool createdByParser)
 {
     // Until the <body> exists, we have no choice but to compare document positions,
     // since styles outside of the body and head continue to be shunted into the head
     // (and thus can shift to end up before dynamically added DOM content that is also
     // outside the body).
     if ((createdByParser && body()) || m_styleSheetCandidateNodes.isEmpty()) {
         m_styleSheetCandidateNodes.add(node);
         return;
     }

     // Determine an appropriate insertion point.
     ListHashSet<Node*>::iterator begin = m_styleSheetCandidateNodes.begin();
     ListHashSet<Node*>::iterator end = m_styleSheetCandidateNodes.end();
     ListHashSet<Node*>::iterator it = end;
     Node* followingNode = 0;
     do {
         --it;
         Node* n = *it;
         unsigned short position = n->compareDocumentPosition(node);
         if (position == DOCUMENT_POSITION_FOLLOWING) {
             m_styleSheetCandidateNodes.insertBefore(followingNode, node);
             return;
         }
         followingNode = n;
     } while (it != begin);

     m_styleSheetCandidateNodes.insertBefore(followingNode, node);
 }

 void Document::removeStyleSheetCandidateNode(Node* node)
 {
     m_styleSheetCandidateNodes.remove(node);
 }

 void Document::recalcStyleSelector()
 {
     if (!renderer() || !attached())
         return;

     StyleSheetVector sheets;

     bool matchAuthorAndUserStyles = true;
     if (Settings* settings = this->settings())
         matchAuthorAndUserStyles = settings->authorAndUserStylesEnabled();

     ListHashSet<Node*>::iterator begin = m_styleSheetCandidateNodes.begin();
     ListHashSet<Node*>::iterator end = m_styleSheetCandidateNodes.end();
     if (!matchAuthorAndUserStyles)
         end = begin;
     for (ListHashSet<Node*>::iterator it = begin; it != end; ++it) {
         Node* n = *it;

         StyleSheet* sheet = 0;

         if (n->nodeType() == PROCESSING_INSTRUCTION_NODE) {
             // Processing instruction (XML documents only)
             ProcessingInstruction* pi = static_cast<ProcessingInstruction*>(n);
             sheet = pi->sheet();
 #if ENABLE(XSLT)
             // Don't apply XSL transforms to already transformed documents -- <rdar://problem/4132806>
             if (pi->isXSL() && !transformSourceDocument()) {
                 // Don't apply XSL transforms until loading is finished.
                 if (!parsing())
                     applyXSLTransform(pi);
                 return;
             }
 #endif
             if (!sheet && !pi->localHref().isEmpty()) {
                 // Processing instruction with reference to an element in this document - e.g.
                 // <?xml-stylesheet href="#mystyle">, with the element
                 // <foo id="mystyle">heading { color: red; }</foo> at some location in
                 // the document
                 Element* elem = getElementById(pi->localHref().impl());
                 if (elem) {
                     String sheetText("");
                     for (Node* c = elem->firstChild(); c; c = c->nextSibling()) {
                         if (c->nodeType() == TEXT_NODE || c->nodeType() == CDATA_SECTION_NODE)
                             sheetText += c->nodeValue();
                     }

                     RefPtr<CSSStyleSheet> cssSheet = CSSStyleSheet::create(this);
                     cssSheet->parseString(sheetText);
                     pi->setCSSStyleSheet(cssSheet);
                     sheet = cssSheet.get();
                 }
             }
         } else if (n->isHTMLElement() && (n->hasTagName(linkTag) || n->hasTagName(styleTag))
 #if ENABLE(SVG)
             ||  (n->isSVGElement() && n->hasTagName(SVGNames::styleTag))
 #endif
         ) {
             Element* e = static_cast<Element*>(n);
             AtomicString title = e->getAttribute(titleAttr);
             bool enabledViaScript = false;
             if (e->hasLocalName(linkTag)) {
                 // <LINK> element
                 HTMLLinkElement* l = static_cast<HTMLLinkElement*>(n);
                 if (l->isDisabled())
                     continue;
                 enabledViaScript = l->isEnabledViaScript();
                 if (l->isLoading()) {
                     // it is loading but we should still decide which style sheet set to use
                     if (!enabledViaScript && !title.isEmpty() && m_preferredStylesheetSet.isEmpty()) {
                         const AtomicString& rel = e->getAttribute(relAttr);
                         if (!rel.contains("alternate")) {
                             m_preferredStylesheetSet = title;
                             m_selectedStylesheetSet = title;
                         }
                     }
                     continue;
                 }
                 if (!l->sheet())
                     title = nullAtom;
             }

             // Get the current preferred styleset.  This is the
             // set of sheets that will be enabled.
 #if ENABLE(SVG)
             if (n->isSVGElement() && n->hasTagName(SVGNames::styleTag))
                 sheet = static_cast<SVGStyleElement*>(n)->sheet();
             else
 #endif
             if (e->hasLocalName(linkTag))
                 sheet = static_cast<HTMLLinkElement*>(n)->sheet();
             else
                 // <STYLE> element
                 sheet = static_cast<HTMLStyleElement*>(n)->sheet();

             // Check to see if this sheet belongs to a styleset
             // (thus making it PREFERRED or ALTERNATE rather than
             // PERSISTENT).
             if (!enabledViaScript && !title.isEmpty()) {
                 // Yes, we have a title.
                 if (m_preferredStylesheetSet.isEmpty()) {
                     // No preferred set has been established.  If
                     // we are NOT an alternate sheet, then establish
                     // us as the preferred set.  Otherwise, just ignore
                     // this sheet.
                     AtomicString rel = e->getAttribute(relAttr);
                     if (e->hasLocalName(styleTag) || !rel.contains("alternate"))
                         m_preferredStylesheetSet = m_selectedStylesheetSet = title;
                 }

                 if (title != m_preferredStylesheetSet)
                     sheet = 0;
             }
         }

         if (sheet)
             sheets.append(sheet);
     }

     m_styleSheets->swap(sheets);

     // Create a new style selector
     delete m_styleSelector;
     m_styleSelector = new CSSStyleSelector(this, userStyleSheet(), m_styleSheets.get(), m_mappedElementSheet.get(), !inCompatMode(), matchAuthorAndUserStyles);
     m_didCalculateStyleSelector = true;
 }

 void Document::setHoverNode(PassRefPtr<Node> newHoverNode)
 {
     m_hoverNode = newHoverNode;
 }

 void Document::setActiveNode(PassRefPtr<Node> newActiveNode)
 {
     m_activeNode = newActiveNode;
 }

 void Document::focusedNodeRemoved()
 {
     setFocusedNode(0);
 }

 void Document::removeFocusedNodeOfSubtree(Node* node, bool amongChildrenOnly)
 {
     if (!m_focusedNode || this->inPageCache()) // If the document is in the page cache, then we don't need to clear out the focused node.
         return;

     bool nodeInSubtree = false;
     if (amongChildrenOnly)
         nodeInSubtree = m_focusedNode->isDescendantOf(node);
     else
         nodeInSubtree = (m_focusedNode == node) || m_focusedNode->isDescendantOf(node);

     if (nodeInSubtree)
         document()->focusedNodeRemoved();
 }

 void Document::hoveredNodeDetached(Node* node)
 {
     if (!m_hoverNode || (node != m_hoverNode && (!m_hoverNode->isTextNode() || node != m_hoverNode->parent())))
         return;

     m_hoverNode = node->parent();
     while (m_hoverNode && !m_hoverNode->renderer())
         m_hoverNode = m_hoverNode->parent();
     if (frame())
         frame()->eventHandler()->scheduleHoverStateUpdate();
 }

 void Document::activeChainNodeDetached(Node* node)
 {
     if (!m_activeNode || (node != m_activeNode && (!m_activeNode->isTextNode() || node != m_activeNode->parent())))
         return;

     m_activeNode = node->parent();
     while (m_activeNode && !m_activeNode->renderer())
         m_activeNode = m_activeNode->parent();
 }

 #if ENABLE(DASHBOARD_SUPPORT)
 const Vector<DashboardRegionValue>& Document::dashboardRegions() const
 {
     return m_dashboardRegions;
 }

 void Document::setDashboardRegions(const Vector<DashboardRegionValue>& regions)
 {
     m_dashboardRegions = regions;
     setDashboardRegionsDirty(false);
 }
 #endif

 bool Document::setFocusedNode(PassRefPtr<Node> newFocusedNode)
 {
     // Make sure newFocusedNode is actually in this document
     if (newFocusedNode && (newFocusedNode->document() != this))
         return true;

     if (m_focusedNode == newFocusedNode)
         return true;

     if (m_inPageCache)
         return false;

     bool focusChangeBlocked = false;
     RefPtr<Node> oldFocusedNode = m_focusedNode;
     m_focusedNode = 0;

     // Remove focus from the existing focus node (if any)
     if (oldFocusedNode && !oldFocusedNode->m_inDetach) {
         if (oldFocusedNode->active())
             oldFocusedNode->setActive(false);

         oldFocusedNode->setFocus(false);

         // Dispatch a change event for text fields or textareas that have been edited
         RenderObject* r = static_cast<RenderObject*>(oldFocusedNode.get()->renderer());
         if (r && r->isTextControl() && toRenderTextControl(r)->isEdited()) {
             oldFocusedNode->dispatchEvent(eventNames().changeEvent, true, false);
             if ((r = static_cast<RenderObject*>(oldFocusedNode.get()->renderer()))) {
                 if (r->isTextControl())
                     toRenderTextControl(r)->setEdited(false);
             }
         }

         // Dispatch the blur event and let the node do any other blur related activities (important for text fields)
         oldFocusedNode->dispatchBlurEvent();

         if (m_focusedNode) {
             // handler shifted focus
             focusChangeBlocked = true;
             newFocusedNode = 0;
         }
         oldFocusedNode->dispatchUIEvent(eventNames().DOMFocusOutEvent, 0, 0);
         if (m_focusedNode) {
             // handler shifted focus
             focusChangeBlocked = true;
             newFocusedNode = 0;
         }
         if ((oldFocusedNode.get() == this) && oldFocusedNode->hasOneRef())
             return true;

         if (oldFocusedNode.get() == oldFocusedNode->rootEditableElement())
             frame()->editor()->didEndEditing();
     }

     if (newFocusedNode) {
         if (newFocusedNode == newFocusedNode->rootEditableElement() && !acceptsEditingFocus(newFocusedNode.get())) {
             // delegate blocks focus change
             focusChangeBlocked = true;
             goto SetFocusedNodeDone;
         }
         // Set focus on the new node
         m_focusedNode = newFocusedNode.get();

         // Dispatch the focus event and let the node do any other focus related activities (important for text fields)
         m_focusedNode->dispatchFocusEvent();

         if (m_focusedNode != newFocusedNode) {
             // handler shifted focus
             focusChangeBlocked = true;
             goto SetFocusedNodeDone;
         }
         m_focusedNode->dispatchUIEvent(eventNames().DOMFocusInEvent, 0, 0);
         if (m_focusedNode != newFocusedNode) {
             // handler shifted focus
             focusChangeBlocked = true;
             goto SetFocusedNodeDone;
         }
         m_focusedNode->setFocus();

         if (m_focusedNode.get() == m_focusedNode->rootEditableElement())
             frame()->editor()->didBeginEditing();

         // eww, I suck. set the qt focus correctly
         // ### find a better place in the code for this
         if (view()) {
             Widget *focusWidget = widgetForNode(m_focusedNode.get());
             if (focusWidget) {
                 // Make sure a widget has the right size before giving it focus.
                 // Otherwise, we are testing edge cases of the Widget code.
                 // Specifically, in WebCore this does not work well for text fields.
                 updateLayout();
                 // Re-get the widget in case updating the layout changed things.
                 focusWidget = widgetForNode(m_focusedNode.get());
             }
             if (focusWidget)
                 focusWidget->setFocus();
             else
                 view()->setFocus();
         }
    }

 #if (PLATFORM(MAC) || PLATFORM(WIN)) && !PLATFORM(CHROMIUM)
     if (!focusChangeBlocked && m_focusedNode && AXObjectCache::accessibilityEnabled())
         axObjectCache()->handleFocusedUIElementChanged();
 #elif PLATFORM(GTK)
     if (!focusChangeBlocked && m_focusedNode && AXObjectCache::accessibilityEnabled()) {
         RenderObject* oldFocusedRenderer = 0;
         RenderObject* newFocusedRenderer = 0;

         if (oldFocusedNode)
             oldFocusedRenderer = oldFocusedNode.get()->renderer();
         if (newFocusedNode)
             newFocusedRenderer = newFocusedNode.get()->renderer();

         axObjectCache()->handleFocusedUIElementChangedWithRenderers(oldFocusedRenderer, newFocusedRenderer);
     }
 #endif

 SetFocusedNodeDone:
     updateStyleIfNeeded();
     return !focusChangeBlocked;
 }

 void Document::getFocusableNodes(Vector<RefPtr<Node> >& nodes)
 {
     updateLayout();

     for (Node* node = firstChild(); node; node = node->traverseNextNode()) {
         if (node->isFocusable())
             nodes.append(node);
     }
 }

 void Document::setCSSTarget(Element* n)
 {
     if (m_cssTarget)
         m_cssTarget->setNeedsStyleRecalc();
     m_cssTarget = n;
     if (n)
         n->setNeedsStyleRecalc();
 }

 void Document::attachNodeIterator(NodeIterator *ni)
 {
     m_nodeIterators.add(ni);
 }

 void Document::detachNodeIterator(NodeIterator *ni)
 {
     m_nodeIterators.remove(ni);
 }

 void Document::nodeChildrenChanged(ContainerNode* container)
 {
     if (!disableRangeMutation(page())) {
         HashSet<Range*>::const_iterator end = m_ranges.end();
         for (HashSet<Range*>::const_iterator it = m_ranges.begin(); it != end; ++it)
             (*it)->nodeChildrenChanged(container);
     }
 }

 void Document::nodeWillBeRemoved(Node* n)
 {
     HashSet<NodeIterator*>::const_iterator nodeIteratorsEnd = m_nodeIterators.end();
     for (HashSet<NodeIterator*>::const_iterator it = m_nodeIterators.begin(); it != nodeIteratorsEnd; ++it)
         (*it)->nodeWillBeRemoved(n);

     if (!disableRangeMutation(page())) {
         HashSet<Range*>::const_iterator rangesEnd = m_ranges.end();
         for (HashSet<Range*>::const_iterator it = m_ranges.begin(); it != rangesEnd; ++it)
             (*it)->nodeWillBeRemoved(n);
     }

     if (Frame* frame = this->frame()) {
         frame->selection()->nodeWillBeRemoved(n);
         frame->dragCaretController()->nodeWillBeRemoved(n);
     }
 }

 void Document::textInserted(Node* text, unsigned offset, unsigned length)
 {
     if (!disableRangeMutation(page())) {
         HashSet<Range*>::const_iterator end = m_ranges.end();
         for (HashSet<Range*>::const_iterator it = m_ranges.begin(); it != end; ++it)
             (*it)->textInserted(text, offset, length);
     }

     // Update the markers for spelling and grammar checking.
     shiftMarkers(text, offset, length);
 }

 void Document::textRemoved(Node* text, unsigned offset, unsigned length)
 {
     if (!disableRangeMutation(page())) {
         HashSet<Range*>::const_iterator end = m_ranges.end();
         for (HashSet<Range*>::const_iterator it = m_ranges.begin(); it != end; ++it)
             (*it)->textRemoved(text, offset, length);
     }

     // Update the markers for spelling and grammar checking.
     removeMarkers(text, offset, length);
     shiftMarkers(text, offset + length, 0 - length);
 }

 void Document::textNodesMerged(Text* oldNode, unsigned offset)
 {
     if (!disableRangeMutation(page())) {
         NodeWithIndex oldNodeWithIndex(oldNode);
         HashSet<Range*>::const_iterator end = m_ranges.end();
         for (HashSet<Range*>::const_iterator it = m_ranges.begin(); it != end; ++it)
             (*it)->textNodesMerged(oldNodeWithIndex, offset);
     }

     // FIXME: This should update markers for spelling and grammar checking.
 }

 void Document::textNodeSplit(Text* oldNode)
 {
     if (!disableRangeMutation(page())) {
         HashSet<Range*>::const_iterator end = m_ranges.end();
         for (HashSet<Range*>::const_iterator it = m_ranges.begin(); it != end; ++it)
             (*it)->textNodeSplit(oldNode);
     }

     // FIXME: This should update markers for spelling and grammar checking.
 }

 // FIXME: eventually, this should return a DOMWindow stored in the document.
 DOMWindow* Document::domWindow() const
 {
     if (!frame())
         return 0;

     // The m_frame pointer is not (not always?) zeroed out when the document is put into b/f cache, so the frame can hold an unrelated document/window pair.
     // FIXME: We should always zero out the frame pointer on navigation to avoid accidentally accessing the new frame content.
     if (m_frame->document() != this)
         return 0;

     return frame()->domWindow();
 }

 void Document::setWindowAttributeEventListener(const AtomicString& eventType, PassRefPtr<EventListener> listener)
 {
     DOMWindow* domWindow = this->domWindow();
     if (!domWindow)
         return;
     domWindow->setAttributeEventListener(eventType, listener);
 }

 EventListener* Document::getWindowAttributeEventListener(const AtomicString& eventType)
 {
     DOMWindow* domWindow = this->domWindow();
     if (!domWindow)
         return 0;
     return domWindow->getAttributeEventListener(eventType);
 }

 void Document::dispatchWindowEvent(PassRefPtr<Event> event)
 {
     ASSERT(!eventDispatchForbidden());
     DOMWindow* domWindow = this->domWindow();
     if (!domWindow)
         return;
     ExceptionCode ec;
     domWindow->dispatchEvent(event, ec);
 }

 void Document::dispatchWindowEvent(const AtomicString& eventType, bool canBubbleArg, bool cancelableArg)
 {
     ASSERT(!eventDispatchForbidden());
     DOMWindow* domWindow = this->domWindow();
     if (!domWindow)
         return;
     domWindow->dispatchEvent(eventType, canBubbleArg, cancelableArg);
 }

 void Document::dispatchLoadEvent()
 {
     ASSERT(!eventDispatchForbidden());
     DOMWindow* domWindow = this->domWindow();
     if (!domWindow)
         return;
     domWindow->dispatchLoadEvent();
 }

 PassRefPtr<Event> Document::createEvent(const String& eventType, ExceptionCode& ec)
 {
     if (eventType == "Event" || eventType == "Events" || eventType == "HTMLEvents")
         return Event::create();
     if (eventType == "KeyboardEvent" || eventType == "KeyboardEvents")
         return KeyboardEvent::create();
     if (eventType == "MessageEvent")
         return MessageEvent::create();
     if (eventType == "MouseEvent" || eventType == "MouseEvents")
         return MouseEvent::create();
     if (eventType == "MutationEvent" || eventType == "MutationEvents")
         return MutationEvent::create();
     if (eventType == "OverflowEvent")
         return OverflowEvent::create();
     if (eventType == "ProgressEvent")
         return ProgressEvent::create();
 #if ENABLE(DOM_STORAGE)
     if (eventType == "StorageEvent")
         return StorageEvent::create();
 #endif
     if (eventType == "TextEvent")
         return TextEvent::create();
     if (eventType == "UIEvent" || eventType == "UIEvents")
         return UIEvent::create();
     if (eventType == "WebKitAnimationEvent")
         return WebKitAnimationEvent::create();
     if (eventType == "WebKitTransitionEvent")
         return WebKitTransitionEvent::create();
     if (eventType == "WheelEvent")
         return WheelEvent::create();
 #if ENABLE(SVG)
     if (eventType == "SVGEvents")
         return Event::create();
     if (eventType == "SVGZoomEvents")
         return SVGZoomEvent::create();
 #endif
     ec = NOT_SUPPORTED_ERR;
     return 0;
 }

 void Document::addListenerTypeIfNeeded(const AtomicString& eventType)
 {
     if (eventType == eventNames().DOMSubtreeModifiedEvent)
         addListenerType(DOMSUBTREEMODIFIED_LISTENER);
     else if (eventType == eventNames().DOMNodeInsertedEvent)
         addListenerType(DOMNODEINSERTED_LISTENER);
     else if (eventType == eventNames().DOMNodeRemovedEvent)
         addListenerType(DOMNODEREMOVED_LISTENER);
     else if (eventType == eventNames().DOMNodeRemovedFromDocumentEvent)
         addListenerType(DOMNODEREMOVEDFROMDOCUMENT_LISTENER);
     else if (eventType == eventNames().DOMNodeInsertedIntoDocumentEvent)
         addListenerType(DOMNODEINSERTEDINTODOCUMENT_LISTENER);
     else if (eventType == eventNames().DOMAttrModifiedEvent)
         addListenerType(DOMATTRMODIFIED_LISTENER);
     else if (eventType == eventNames().DOMCharacterDataModifiedEvent)
         addListenerType(DOMCHARACTERDATAMODIFIED_LISTENER);
     else if (eventType == eventNames().overflowchangedEvent)
         addListenerType(OVERFLOWCHANGED_LISTENER);
     else if (eventType == eventNames().webkitAnimationStartEvent)
         addListenerType(ANIMATIONSTART_LISTENER);
     else if (eventType == eventNames().webkitAnimationEndEvent)
         addListenerType(ANIMATIONEND_LISTENER);
     else if (eventType == eventNames().webkitAnimationIterationEvent)
         addListenerType(ANIMATIONITERATION_LISTENER);
     else if (eventType == eventNames().webkitTransitionEndEvent)
         addListenerType(TRANSITIONEND_LISTENER);
 }

 CSSStyleDeclaration* Document::getOverrideStyle(Element*, const String&)
 {
     return 0;
 }

 Element* Document::ownerElement() const
 {
     if (!frame())
         return 0;
     return frame()->ownerElement();
 }

 String Document::cookie() const
 {
     if (page() && !page()->cookieEnabled())
         return String();

     KURL cookieURL = this->cookieURL();
     if (cookieURL.isEmpty())
         return String();

     return cookies(this, cookieURL);
 }

 void Document::setCookie(const String& value)
 {
     if (page() && !page()->cookieEnabled())
         return;

     KURL cookieURL = this->cookieURL();
     if (cookieURL.isEmpty())
         return;

     setCookies(this, cookieURL, value);
 }

 String Document::referrer() const
 {
     if (frame())
         return frame()->loader()->referrer();
     return String();
 }

 String Document::domain() const
 {
     return securityOrigin()->domain();
 }

 void Document::setDomain(const String& newDomain)
 {
     // Both NS and IE specify that changing the domain is only allowed when
     // the new domain is a suffix of the old domain.

     // FIXME: We should add logging indicating why a domain was not allowed.

     // If the new domain is the same as the old domain, still call
     // securityOrigin()->setDomainForDOM. This will change the
     // security check behavior. For example, if a page loaded on port 8000
     // assigns its current domain using document.domain, the page will
     // allow other pages loaded on different ports in the same domain that
     // have also assigned to access this page.
     if (equalIgnoringCase(domain(), newDomain)) {
         securityOrigin()->setDomainFromDOM(newDomain);
         if (m_frame)
             m_frame->script()->updateSecurityOrigin();
         return;
     }

     int oldLength = domain().length();
     int newLength = newDomain.length();
     // e.g. newDomain = webkit.org (10) and domain() = www.webkit.org (14)
     if (newLength >= oldLength)
         return;

     String test = domain();
     // Check that it's a subdomain, not e.g. "ebkit.org"
     if (test[oldLength - newLength - 1] != '.')
         return;

     // Now test is "webkit.org" from domain()
     // and we check that it's the same thing as newDomain
     test.remove(0, oldLength - newLength);
     if (test != newDomain)
         return;

     securityOrigin()->setDomainFromDOM(newDomain);
     if (m_frame)
         m_frame->script()->updateSecurityOrigin();
 }

 String Document::lastModified() const
 {
     Frame* f = frame();
     if (!f)
         return String();
     DocumentLoader* loader = f->loader()->documentLoader();
     if (!loader)
         return String();
     return loader->response().httpHeaderField("Last-Modified");
 }

 static bool isValidNameNonASCII(const UChar* characters, unsigned length)
 {
     unsigned i = 0;

     UChar32 c;
     U16_NEXT(characters, i, length, c)
     if (!isValidNameStart(c))
         return false;

     while (i < length) {
         U16_NEXT(characters, i, length, c)
         if (!isValidNamePart(c))
             return false;
     }

     return true;
 }

 static inline bool isValidNameASCII(const UChar* characters, unsigned length)
 {
     UChar c = characters[0];
     if (!(isASCIIAlpha(c) || c == ':' || c == '_'))
         return false;

     for (unsigned i = 1; i < length; ++i) {
         c = characters[i];
         if (!(isASCIIAlphanumeric(c) || c == ':' || c == '_' || c == '-' || c == '.'))
             return false;
     }

     return true;
 }

 bool Document::isValidName(const String& name)
 {
     unsigned length = name.length();
     if (!length)
         return false;

     const UChar* characters = name.characters();
     return isValidNameASCII(characters, length) || isValidNameNonASCII(characters, length);
 }

 bool Document::parseQualifiedName(const String& qualifiedName, String& prefix, String& localName, ExceptionCode& ec)
 {
     unsigned length = qualifiedName.length();

     if (length == 0) {
         ec = INVALID_CHARACTER_ERR;
         return false;
     }

     bool nameStart = true;
     bool sawColon = false;
     int colonPos = 0;

     const UChar* s = qualifiedName.characters();
     for (unsigned i = 0; i < length;) {
         UChar32 c;
         U16_NEXT(s, i, length, c)
         if (c == ':') {
             if (sawColon) {
                 ec = NAMESPACE_ERR;
                 return false; // multiple colons: not allowed
             }
             nameStart = true;
             sawColon = true;
             colonPos = i - 1;
         } else if (nameStart) {
             if (!isValidNameStart(c)) {
                 ec = INVALID_CHARACTER_ERR;
                 return false;
             }
             nameStart = false;
         } else {
             if (!isValidNamePart(c)) {
                 ec = INVALID_CHARACTER_ERR;
                 return false;
             }
         }
     }

     if (!sawColon) {
         prefix = String();
         localName = qualifiedName;
     } else {
         prefix = qualifiedName.substring(0, colonPos);
         if (prefix.isEmpty()) {
             ec = NAMESPACE_ERR;
             return false;
         }
         localName = qualifiedName.substring(colonPos + 1);
     }

     if (localName.isEmpty()) {
         ec = NAMESPACE_ERR;
         return false;
     }

     return true;
 }

 void Document::addImageMap(HTMLMapElement* imageMap)
 {
     const AtomicString& name = imageMap->getName();
     if (!name.impl())
         return;

     // Add the image map, unless there's already another with that name.
     // "First map wins" is the rule other browsers seem to implement.
     m_imageMapsByName.add(name.impl(), imageMap);
 }

 void Document::removeImageMap(HTMLMapElement* imageMap)
 {
     // Remove the image map by name.
     // But don't remove some other image map that just happens to have the same name.
     // FIXME: Use a HashCountedSet as we do for IDs to find the first remaining map
     // once a map has been removed.
     const AtomicString& name = imageMap->getName();
     if (!name.impl())
         return;

     ImageMapsByName::iterator it = m_imageMapsByName.find(name.impl());
     if (it != m_imageMapsByName.end() && it->second == imageMap)
         m_imageMapsByName.remove(it);
 }

 HTMLMapElement *Document::getImageMap(const String& url) const
 {
     if (url.isNull())
         return 0;
     int hashPos = url.find('#');
     String name = (hashPos < 0 ? url : url.substring(hashPos + 1)).impl();
     AtomicString mapName = isHTMLDocument() ? name.lower() : name;
     return m_imageMapsByName.get(mapName.impl());
 }

 void Document::setDecoder(PassRefPtr<TextResourceDecoder> decoder)
 {
     m_decoder = decoder;
 }

 KURL Document::completeURL(const String& url) const
 {
     // Always return a null URL when passed a null string.
     // FIXME: Should we change the KURL constructor to have this behavior?
     // See also [CSS]StyleSheet::completeURL(const String&)
     if (url.isNull())
         return KURL();
     const KURL& baseURL = ((m_baseURL.isEmpty() || m_baseURL == blankURL()) && parentDocument()) ? parentDocument()->baseURL() : m_baseURL;
     if (!m_decoder)
         return KURL(baseURL, url);
     return KURL(baseURL, url, m_decoder->encoding());
 }

 void Document::setInPageCache(bool flag)
 {
     if (m_inPageCache == flag)
         return;

     m_inPageCache = flag;
     if (flag) {
         ASSERT(m_savedRenderer == 0);
         m_savedRenderer = renderer();
         if (FrameView* v = view())
             v->resetScrollbars();
         unscheduleStyleRecalc();
     } else {
         ASSERT(renderer() == 0 || renderer() == m_savedRenderer);
         ASSERT(m_renderArena);
         setRenderer(m_savedRenderer);
         m_savedRenderer = 0;
         if (childNeedsStyleRecalc())
             scheduleStyleRecalc();
     }
 }

 void Document::documentWillBecomeInactive()
 {
 #if USE(ACCELERATED_COMPOSITING)
     if (renderer())
         renderView()->willMoveOffscreen();
 #endif

     HashSet<Element*>::iterator end = m_documentActivationCallbackElements.end();
     for (HashSet<Element*>::iterator i = m_documentActivationCallbackElements.begin(); i != end; ++i)
         (*i)->documentWillBecomeInactive();
 }

 void Document::documentDidBecomeActive()
 {
     HashSet<Element*>::iterator end = m_documentActivationCallbackElements.end();
     for (HashSet<Element*>::iterator i = m_documentActivationCallbackElements.begin(); i != end; ++i)
         (*i)->documentDidBecomeActive();

 #if USE(ACCELERATED_COMPOSITING)
     if (renderer())
         renderView()->didMoveOnscreen();
 #endif
 }

 void Document::registerForDocumentActivationCallbacks(Element* e)
 {
     m_documentActivationCallbackElements.add(e);
 }

 void Document::unregisterForDocumentActivationCallbacks(Element* e)
 {
     m_documentActivationCallbackElements.remove(e);
 }

 void Document::mediaVolumeDidChange()
 {
     HashSet<Element*>::iterator end = m_mediaVolumeCallbackElements.end();
     for (HashSet<Element*>::iterator i = m_mediaVolumeCallbackElements.begin(); i != end; ++i)
         (*i)->mediaVolumeDidChange();
 }

 void Document::registerForMediaVolumeCallbacks(Element* e)
 {
     m_mediaVolumeCallbackElements.add(e);
 }

 void Document::unregisterForMediaVolumeCallbacks(Element* e)
 {
     m_mediaVolumeCallbackElements.remove(e);
 }

 void Document::setShouldCreateRenderers(bool f)
 {
     m_createRenderers = f;
 }

 bool Document::shouldCreateRenderers()
 {
     return m_createRenderers;
 }

 // Support for Javascript execCommand, and related methods

 static Editor::Command command(Document* document, const String& commandName, bool userInterface = false)
 {
     Frame* frame = document->frame();
     if (!frame || frame->document() != document)
         return Editor::Command();
     return frame->editor()->command(commandName,
         userInterface ? CommandFromDOMWithUserInterface : CommandFromDOM);
 }

 bool Document::execCommand(const String& commandName, bool userInterface, const String& value)
 {
     return command(this, commandName, userInterface).execute(value);
 }

 bool Document::queryCommandEnabled(const String& commandName)
 {
     return command(this, commandName).isEnabled();
 }

 bool Document::queryCommandIndeterm(const String& commandName)
 {
     return command(this, commandName).state() == MixedTriState;
 }

 bool Document::queryCommandState(const String& commandName)
 {
     return command(this, commandName).state() != FalseTriState;
 }

 bool Document::queryCommandSupported(const String& commandName)
 {
     return command(this, commandName).isSupported();
 }

 String Document::queryCommandValue(const String& commandName)
 {
     return command(this, commandName).value();
 }

 static IntRect placeholderRectForMarker()
 {
     return IntRect(-1, -1, -1, -1);
 }

 void Document::addMarker(Range *range, DocumentMarker::MarkerType type, String description)
 {
     // Use a TextIterator to visit the potentially multiple nodes the range covers.
     for (TextIterator markedText(range); !markedText.atEnd(); markedText.advance()) {
         RefPtr<Range> textPiece = markedText.range();
         int exception = 0;
         DocumentMarker marker = {type, textPiece->startOffset(exception), textPiece->endOffset(exception), description, false};
         addMarker(textPiece->startContainer(exception), marker);
     }
 }

 void Document::removeMarkers(Range* range, DocumentMarker::MarkerType markerType)
 {
     if (m_markers.isEmpty())
         return;

     ExceptionCode ec = 0;
     Node* startContainer = range->startContainer(ec);
     Node* endContainer = range->endContainer(ec);

     Node* pastLastNode = range->pastLastNode();
     for (Node* node = range->firstNode(); node != pastLastNode; node = node->traverseNextNode()) {
         int startOffset = node == startContainer ? range->startOffset(ec) : 0;
         int endOffset = node == endContainer ? range->endOffset(ec) : INT_MAX;
         int length = endOffset - startOffset;
         removeMarkers(node, startOffset, length, markerType);
     }
 }

 // Markers are stored in order sorted by their start offset.
 // Markers of the same type do not overlap each other.

 void Document::addMarker(Node* node, DocumentMarker newMarker)
 {
     ASSERT(newMarker.endOffset >= newMarker.startOffset);
     if (newMarker.endOffset == newMarker.startOffset)
         return;

     MarkerMapVectorPair* vectorPair = m_markers.get(node);

     if (!vectorPair) {
         vectorPair = new MarkerMapVectorPair;
         vectorPair->first.append(newMarker);
         vectorPair->second.append(placeholderRectForMarker());
         m_markers.set(node, vectorPair);
     } else {
         Vector<DocumentMarker>& markers = vectorPair->first;
         Vector<IntRect>& rects = vectorPair->second;
         size_t numMarkers = markers.size();
         ASSERT(numMarkers == rects.size());
         size_t i;
         // Iterate over all markers whose start offset is less than or equal to the new marker's.
         // If one of them is of the same type as the new marker and touches it or intersects with it
         // (there is at most one), remove it and adjust the new marker's start offset to encompass it.
         for (i = 0; i < numMarkers; ++i) {
             DocumentMarker marker = markers[i];
             if (marker.startOffset > newMarker.startOffset)
                 break;
             if (marker.type == newMarker.type && marker.endOffset >= newMarker.startOffset) {
                 newMarker.startOffset = marker.startOffset;
                 markers.remove(i);
                 rects.remove(i);
                 numMarkers--;
                 break;
             }
         }
         size_t j = i;
         // Iterate over all markers whose end offset is less than or equal to the new marker's,
         // removing markers of the same type as the new marker which touch it or intersect with it,
         // adjusting the new marker's end offset to cover them if necessary.
         while (j < numMarkers) {
             DocumentMarker marker = markers[j];
             if (marker.startOffset > newMarker.endOffset)
                 break;
             if (marker.type == newMarker.type) {
                 markers.remove(j);
                 rects.remove(j);
                 if (newMarker.endOffset <= marker.endOffset) {
                     newMarker.endOffset = marker.endOffset;
                     break;
                 }
                 numMarkers--;
             } else
                 j++;
         }
         // At this point i points to the node before which we want to insert.
         markers.insert(i, newMarker);
         rects.insert(i, placeholderRectForMarker());
     }

     // repaint the affected node
     if (node->renderer())
         node->renderer()->repaint();
 }

 // copies markers from srcNode to dstNode, applying the specified shift delta to the copies.  The shift is
 // useful if, e.g., the caller has created the dstNode from a non-prefix substring of the srcNode.
 void Document::copyMarkers(Node *srcNode, unsigned startOffset, int length, Node *dstNode, int delta, DocumentMarker::MarkerType markerType)
 {
     if (length <= 0)
         return;

     MarkerMapVectorPair* vectorPair = m_markers.get(srcNode);
     if (!vectorPair)
         return;

     ASSERT(vectorPair->first.size() == vectorPair->second.size());

     bool docDirty = false;
     unsigned endOffset = startOffset + length - 1;
     Vector<DocumentMarker>& markers = vectorPair->first;
     for (size_t i = 0; i != markers.size(); ++i) {
         DocumentMarker marker = markers[i];

         // stop if we are now past the specified range
         if (marker.startOffset > endOffset)
             break;

         // skip marker that is before the specified range or is the wrong type
         if (marker.endOffset < startOffset || (marker.type != markerType && markerType != DocumentMarker::AllMarkers))
             continue;

         // pin the marker to the specified range and apply the shift delta
         docDirty = true;
         if (marker.startOffset < startOffset)
             marker.startOffset = startOffset;
         if (marker.endOffset > endOffset)
             marker.endOffset = endOffset;
         marker.startOffset += delta;
         marker.endOffset += delta;

         addMarker(dstNode, marker);
     }

     // repaint the affected node
     if (docDirty && dstNode->renderer())
         dstNode->renderer()->repaint();
 }

 void Document::removeMarkers(Node* node, unsigned startOffset, int length, DocumentMarker::MarkerType markerType)
 {
     if (length <= 0)
         return;

     MarkerMapVectorPair* vectorPair = m_markers.get(node);
     if (!vectorPair)
         return;

     Vector<DocumentMarker>& markers = vectorPair->first;
     Vector<IntRect>& rects = vectorPair->second;
     ASSERT(markers.size() == rects.size());
     bool docDirty = false;
     unsigned endOffset = startOffset + length;
     for (size_t i = 0; i < markers.size();) {
         DocumentMarker marker = markers[i];

         // markers are returned in order, so stop if we are now past the specified range
         if (marker.startOffset >= endOffset)
             break;

         // skip marker that is wrong type or before target
         if (marker.endOffset < startOffset || (marker.type != markerType && markerType != DocumentMarker::AllMarkers)) {
             i++;
             continue;
         }

         // at this point we know that marker and target intersect in some way
         docDirty = true;

         // pitch the old marker and any associated rect
         markers.remove(i);
         rects.remove(i);

         // add either of the resulting slices that are left after removing target
         if (startOffset > marker.startOffset) {
             DocumentMarker newLeft = marker;
             newLeft.endOffset = startOffset;
             markers.insert(i, newLeft);
             rects.insert(i, placeholderRectForMarker());
             // i now points to the newly-inserted node, but we want to skip that one
             i++;
         }
         if (marker.endOffset > endOffset) {
             DocumentMarker newRight = marker;
             newRight.startOffset = endOffset;
             markers.insert(i, newRight);
             rects.insert(i, placeholderRectForMarker());
             // i now points to the newly-inserted node, but we want to skip that one
             i++;
         }
     }

     if (markers.isEmpty()) {
         ASSERT(rects.isEmpty());
         m_markers.remove(node);
         delete vectorPair;
     }

     // repaint the affected node
     if (docDirty && node->renderer())
         node->renderer()->repaint();
 }

 DocumentMarker* Document::markerContainingPoint(const IntPoint& point, DocumentMarker::MarkerType markerType)
 {
     // outer loop: process each node that contains any markers
     MarkerMap::iterator end = m_markers.end();
     for (MarkerMap::iterator nodeIterator = m_markers.begin(); nodeIterator != end; ++nodeIterator) {
         // inner loop; process each marker in this node
         MarkerMapVectorPair* vectorPair = nodeIterator->second;
         Vector<DocumentMarker>& markers = vectorPair->first;
         Vector<IntRect>& rects = vectorPair->second;
         ASSERT(markers.size() == rects.size());
         unsigned markerCount = markers.size();
         for (unsigned markerIndex = 0; markerIndex < markerCount; ++markerIndex) {
             DocumentMarker& marker = markers[markerIndex];

             // skip marker that is wrong type
             if (marker.type != markerType && markerType != DocumentMarker::AllMarkers)
                 continue;

             IntRect& r = rects[markerIndex];

             // skip placeholder rects
             if (r == placeholderRectForMarker())
                 continue;

             if (r.contains(point))
                 return &marker;
         }
     }

     return 0;
 }

 Vector<DocumentMarker> Document::markersForNode(Node* node)
 {
     MarkerMapVectorPair* vectorPair = m_markers.get(node);
     if (vectorPair)
         return vectorPair->first;
     return Vector<DocumentMarker>();
 }

 Vector<IntRect> Document::renderedRectsForMarkers(DocumentMarker::MarkerType markerType)
 {
     Vector<IntRect> result;

     // outer loop: process each node
     MarkerMap::iterator end = m_markers.end();
     for (MarkerMap::iterator nodeIterator = m_markers.begin(); nodeIterator != end; ++nodeIterator) {
         // inner loop; process each marker in this node
         MarkerMapVectorPair* vectorPair = nodeIterator->second;
         Vector<DocumentMarker>& markers = vectorPair->first;
         Vector<IntRect>& rects = vectorPair->second;
         ASSERT(markers.size() == rects.size());
         unsigned markerCount = markers.size();
         for (unsigned markerIndex = 0; markerIndex < markerCount; ++markerIndex) {
             DocumentMarker marker = markers[markerIndex];

             // skip marker that is wrong type
             if (marker.type != markerType && markerType != DocumentMarker::AllMarkers)
                 continue;

             IntRect r = rects[markerIndex];
             // skip placeholder rects
             if (r == placeholderRectForMarker())
                 continue;

             result.append(r);
         }
     }

     return result;
 }

 void Document::removeMarkers(Node* node)
 {
     MarkerMap::iterator i = m_markers.find(node);
     if (i != m_markers.end()) {
         delete i->second;
         m_markers.remove(i);
         if (RenderObject* renderer = node->renderer())
             renderer->repaint();
     }
 }

 void Document::removeMarkers(DocumentMarker::MarkerType markerType)
 {
     // outer loop: process each markered node in the document
     MarkerMap markerMapCopy = m_markers;
     MarkerMap::iterator end = markerMapCopy.end();
     for (MarkerMap::iterator i = markerMapCopy.begin(); i != end; ++i) {
         Node* node = i->first.get();
         bool nodeNeedsRepaint = false;

         // inner loop: process each marker in the current node
         MarkerMapVectorPair* vectorPair = i->second;
         Vector<DocumentMarker>& markers = vectorPair->first;
         Vector<IntRect>& rects = vectorPair->second;
         ASSERT(markers.size() == rects.size());
         for (size_t i = 0; i != markers.size();) {
             DocumentMarker marker = markers[i];

             // skip nodes that are not of the specified type
             if (marker.type != markerType && markerType != DocumentMarker::AllMarkers) {
                 ++i;
                 continue;
             }

             // pitch the old marker
             markers.remove(i);
             rects.remove(i);
             nodeNeedsRepaint = true;
             // markerIterator now points to the next node
         }

         // Redraw the node if it changed. Do this before the node is removed from m_markers, since
         // m_markers might contain the last reference to the node.
         if (nodeNeedsRepaint) {
             RenderObject* renderer = node->renderer();
             if (renderer)
                 renderer->repaint();
         }

         // delete the node's list if it is now empty
         if (markers.isEmpty()) {
             ASSERT(rects.isEmpty());
             m_markers.remove(node);
             delete vectorPair;
         }
     }
 }

 void Document::repaintMarkers(DocumentMarker::MarkerType markerType)
 {
     // outer loop: process each markered node in the document
     MarkerMap::iterator end = m_markers.end();
     for (MarkerMap::iterator i = m_markers.begin(); i != end; ++i) {
         Node* node = i->first.get();

         // inner loop: process each marker in the current node
         MarkerMapVectorPair* vectorPair = i->second;
         Vector<DocumentMarker>& markers = vectorPair->first;
         bool nodeNeedsRepaint = false;
         for (size_t i = 0; i != markers.size(); ++i) {
             DocumentMarker marker = markers[i];

             // skip nodes that are not of the specified type
             if (marker.type == markerType || markerType == DocumentMarker::AllMarkers) {
                 nodeNeedsRepaint = true;
                 break;
             }
         }

         if (!nodeNeedsRepaint)
             continue;

         // cause the node to be redrawn
         if (RenderObject* renderer = node->renderer())
             renderer->repaint();
     }
 }

 void Document::setRenderedRectForMarker(Node* node, DocumentMarker marker, const IntRect& r)
 {
     MarkerMapVectorPair* vectorPair = m_markers.get(node);
     if (!vectorPair) {
         ASSERT_NOT_REACHED(); // shouldn't be trying to set the rect for a marker we don't already know about
         return;
     }

     Vector<DocumentMarker>& markers = vectorPair->first;
     ASSERT(markers.size() == vectorPair->second.size());
     unsigned markerCount = markers.size();
     for (unsigned markerIndex = 0; markerIndex < markerCount; ++markerIndex) {
         DocumentMarker m = markers[markerIndex];
         if (m == marker) {
             vectorPair->second[markerIndex] = r;
             return;
         }
     }

     ASSERT_NOT_REACHED(); // shouldn't be trying to set the rect for a marker we don't already know about
 }

 void Document::invalidateRenderedRectsForMarkersInRect(const IntRect& r)
 {
     // outer loop: process each markered node in the document
     MarkerMap::iterator end = m_markers.end();
     for (MarkerMap::iterator i = m_markers.begin(); i != end; ++i) {

         // inner loop: process each rect in the current node
         MarkerMapVectorPair* vectorPair = i->second;
         Vector<IntRect>& rects = vectorPair->second;

         unsigned rectCount = rects.size();
         for (unsigned rectIndex = 0; rectIndex < rectCount; ++rectIndex)
             if (rects[rectIndex].intersects(r))
                 rects[rectIndex] = placeholderRectForMarker();
     }
 }

 void Document::shiftMarkers(Node *node, unsigned startOffset, int delta, DocumentMarker::MarkerType markerType)
 {
     MarkerMapVectorPair* vectorPair = m_markers.get(node);
     if (!vectorPair)
         return;

     Vector<DocumentMarker>& markers = vectorPair->first;
     Vector<IntRect>& rects = vectorPair->second;
     ASSERT(markers.size() == rects.size());

     bool docDirty = false;
     for (size_t i = 0; i != markers.size(); ++i) {
         DocumentMarker &marker = markers[i];
         if (marker.startOffset >= startOffset && (markerType == DocumentMarker::AllMarkers || marker.type == markerType)) {
             ASSERT((int)marker.startOffset + delta >= 0);
             marker.startOffset += delta;
             marker.endOffset += delta;
             docDirty = true;

             // Marker moved, so previously-computed rendered rectangle is now invalid
             rects[i] = placeholderRectForMarker();
         }
     }

     // repaint the affected node
     if (docDirty && node->renderer())
         node->renderer()->repaint();
 }

 void Document::setMarkersActive(Range* range, bool active)
 {
     if (m_markers.isEmpty())
         return;

     ExceptionCode ec = 0;
     Node* startContainer = range->startContainer(ec);
     Node* endContainer = range->endContainer(ec);

     Node* pastLastNode = range->pastLastNode();
     for (Node* node = range->firstNode(); node != pastLastNode; node = node->traverseNextNode()) {
         int startOffset = node == startContainer ? range->startOffset(ec) : 0;
         int endOffset = node == endContainer ? range->endOffset(ec) : INT_MAX;
         setMarkersActive(node, startOffset, endOffset, active);
     }
 }

 void Document::setMarkersActive(Node* node, unsigned startOffset, unsigned endOffset, bool active)
 {
     MarkerMapVectorPair* vectorPair = m_markers.get(node);
     if (!vectorPair)
         return;

     Vector<DocumentMarker>& markers = vectorPair->first;
     ASSERT(markers.size() == vectorPair->second.size());

     bool docDirty = false;
     for (size_t i = 0; i != markers.size(); ++i) {
         DocumentMarker &marker = markers[i];

         // Markers are returned in order, so stop if we are now past the specified range.
         if (marker.startOffset >= endOffset)
             break;

         // Skip marker that is wrong type or before target.
         if (marker.endOffset < startOffset || marker.type != DocumentMarker::TextMatch)
             continue;

         marker.activeMatch = active;
         docDirty = true;
     }

     // repaint the affected node
     if (docDirty && node->renderer())
         node->renderer()->repaint();
 }

 #if ENABLE(XSLT)

 void Document::applyXSLTransform(ProcessingInstruction* pi)
 {
     RefPtr<XSLTProcessor> processor = XSLTProcessor::create();
     processor->setXSLStyleSheet(static_cast<XSLStyleSheet*>(pi->sheet()));
     String resultMIMEType;
     String newSource;
     String resultEncoding;
     if (!processor->transformToString(this, resultMIMEType, newSource, resultEncoding))
         return;
     // FIXME: If the transform failed we should probably report an error (like Mozilla does).
     processor->createDocumentFromSource(newSource, resultEncoding, resultMIMEType, this, frame());
 }

 void Document::setTransformSource(void* doc)
 {
     if (doc == m_transformSource)
         return;

     xmlFreeDoc((xmlDocPtr)m_transformSource);
     m_transformSource = doc;
 }

 #endif

 void Document::setDesignMode(InheritedBool value)
 {
     m_designMode = value;
 }

 Document::InheritedBool Document::getDesignMode() const
 {
     return m_designMode;
 }

 bool Document::inDesignMode() const
 {
     for (const Document* d = this; d; d = d->parentDocument()) {
         if (d->m_designMode != inherit)
             return d->m_designMode;
     }
     return false;
 }

 Document *Document::parentDocument() const
 {
     Frame *childPart = frame();
     if (!childPart)
         return 0;
     Frame *parent = childPart->tree()->parent();
     if (!parent)
         return 0;
     return parent->document();
 }

 Document *Document::topDocument() const
 {
     Document *doc = const_cast<Document *>(this);
     Element *element;
     while ((element = doc->ownerElement()))
         doc = element->document();

     return doc;
 }

 PassRefPtr<Attr> Document::createAttribute(const String& name, ExceptionCode& ec)
 {
     return createAttributeNS(String(), name, ec, true);
 }

 PassRefPtr<Attr> Document::createAttributeNS(const String& namespaceURI, const String& qualifiedName, ExceptionCode& ec, bool shouldIgnoreNamespaceChecks)
 {
     String prefix, localName;
     if (!parseQualifiedName(qualifiedName, prefix, localName, ec))
         return 0;

     QualifiedName qName(prefix, localName, namespaceURI);
     if (!shouldIgnoreNamespaceChecks && hasPrefixNamespaceMismatch(qName)) {
         ec = NAMESPACE_ERR;
         return 0;
     }

     // Spec: DOM Level 2 Core: http://www.w3.org/TR/DOM-Level-2-Core/core.html#ID-DocCrAttrNS
     if (!shouldIgnoreNamespaceChecks && qName.localName() == "xmlns" && qName.namespaceURI() != "http://www.w3.org/2000/xmlns/") {
         ec = NAMESPACE_ERR;
         return 0;
     }

     // FIXME: Assume this is a mapped attribute, since createAttribute isn't namespace-aware.  There's no harm to XML
     // documents if we're wrong.
     return new Attr(0, this, MappedAttribute::create(qName, StringImpl::empty()));
 }

 #if ENABLE(SVG)
 const SVGDocumentExtensions* Document::svgExtensions()
 {
     return m_svgExtensions.get();
 }

 SVGDocumentExtensions* Document::accessSVGExtensions()
 {
     if (!m_svgExtensions)
         m_svgExtensions.set(new SVGDocumentExtensions(this));
     return m_svgExtensions.get();
 }
 #endif

 PassRefPtr<HTMLCollection> Document::images()
 {
     return HTMLCollection::create(this, DocImages);
 }

 PassRefPtr<HTMLCollection> Document::applets()
 {
     return HTMLCollection::create(this, DocApplets);
 }

 PassRefPtr<HTMLCollection> Document::embeds()
 {
     return HTMLCollection::create(this, DocEmbeds);
 }

 PassRefPtr<HTMLCollection> Document::plugins()
 {
     // This is an alias for embeds() required for the JS DOM bindings.
     return HTMLCollection::create(this, DocEmbeds);
 }

 PassRefPtr<HTMLCollection> Document::objects()
 {
     return HTMLCollection::create(this, DocObjects);
 }

 PassRefPtr<HTMLCollection> Document::scripts()
 {
     return HTMLCollection::create(this, DocScripts);
 }

 PassRefPtr<HTMLCollection> Document::links()
 {
     return HTMLCollection::create(this, DocLinks);
 }

 PassRefPtr<HTMLCollection> Document::forms()
 {
     return HTMLCollection::create(this, DocForms);
 }

 PassRefPtr<HTMLCollection> Document::anchors()
 {
     return HTMLCollection::create(this, DocAnchors);
 }

 PassRefPtr<HTMLCollection> Document::all()
 {
     return HTMLCollection::create(this, DocAll);
 }

 PassRefPtr<HTMLCollection> Document::windowNamedItems(const String &name)
 {
     return HTMLNameCollection::create(this, WindowNamedItems, name);
 }

 PassRefPtr<HTMLCollection> Document::documentNamedItems(const String &name)
 {
     return HTMLNameCollection::create(this, DocumentNamedItems, name);
 }

 CollectionCache* Document::nameCollectionInfo(CollectionType type, const AtomicString& name)
 {
     ASSERT(type >= FirstNamedDocumentCachedType);
     unsigned index = type - FirstNamedDocumentCachedType;
     ASSERT(index < NumNamedDocumentCachedTypes);

     NamedCollectionMap& map = m_nameCollectionInfo[index];
     NamedCollectionMap::iterator iter = map.find(name.impl());
     if (iter == map.end())
         iter = map.add(name.impl(), new CollectionCache).first;
     return iter->second;
 }

 void Document::finishedParsing()
 {
     setParsing(false);

     ExceptionCode ec = 0;
     dispatchEvent(Event::create(eventNames().DOMContentLoadedEvent, true, false), ec);

     if (Frame* f = frame())
         f->loader()->finishedParsing();
 }

 Vector<String> Document::formElementsState() const
 {
     Vector<String> stateVector;
     stateVector.reserveInitialCapacity(m_formElementsWithState.size() * 3);
     typedef ListHashSet<Element*>::const_iterator Iterator;
     Iterator end = m_formElementsWithState.end();
     for (Iterator it = m_formElementsWithState.begin(); it != end; ++it) {
         Element* e = *it;
         String value;
         if (e->saveFormControlState(value)) {
             stateVector.append(e->formControlName().string());
             stateVector.append(e->formControlType().string());
             stateVector.append(value);
         }
     }
     return stateVector;
 }

 #if ENABLE(XPATH)

 PassRefPtr<XPathExpression> Document::createExpression(const String& expression,
                                                        XPathNSResolver* resolver,
                                                        ExceptionCode& ec)
 {
     if (!m_xpathEvaluator)
         m_xpathEvaluator = XPathEvaluator::create();
     return m_xpathEvaluator->createExpression(expression, resolver, ec);
 }

 PassRefPtr<XPathNSResolver> Document::createNSResolver(Node* nodeResolver)
 {
     if (!m_xpathEvaluator)
         m_xpathEvaluator = XPathEvaluator::create();
     return m_xpathEvaluator->createNSResolver(nodeResolver);
 }

 PassRefPtr<XPathResult> Document::evaluate(const String& expression,
                                            Node* contextNode,
                                            XPathNSResolver* resolver,
                                            unsigned short type,
                                            XPathResult* result,
                                            ExceptionCode& ec)
 {
     if (!m_xpathEvaluator)
         m_xpathEvaluator = XPathEvaluator::create();
     return m_xpathEvaluator->evaluate(expression, contextNode, resolver, type, result, ec);
 }

 #endif // ENABLE(XPATH)

 void Document::setStateForNewFormElements(const Vector<String>& stateVector)
 {
     // Walk the state vector backwards so that the value to use for each
     // name/type pair first is the one at the end of each individual vector
     // in the FormElementStateMap. We're using them like stacks.
     typedef FormElementStateMap::iterator Iterator;
     m_formElementsWithState.clear();
     for (size_t i = stateVector.size() / 3 * 3; i; i -= 3) {
         AtomicString a = stateVector[i - 3];
         AtomicString b = stateVector[i - 2];
         const String& c = stateVector[i - 1];
         FormElementKey key(a.impl(), b.impl());
         Iterator it = m_stateForNewFormElements.find(key);
         if (it != m_stateForNewFormElements.end())
             it->second.append(c);
         else {
             Vector<String> v(1);
             v[0] = c;
             m_stateForNewFormElements.set(key, v);
         }
     }
 }

 bool Document::hasStateForNewFormElements() const
 {
     return !m_stateForNewFormElements.isEmpty();
 }

 bool Document::takeStateForFormElement(AtomicStringImpl* name, AtomicStringImpl* type, String& state)
 {
     typedef FormElementStateMap::iterator Iterator;
     Iterator it = m_stateForNewFormElements.find(FormElementKey(name, type));
     if (it == m_stateForNewFormElements.end())
         return false;
     ASSERT(it->second.size());
     state = it->second.last();
     if (it->second.size() > 1)
         it->second.removeLast();
     else
         m_stateForNewFormElements.remove(it);
     return true;
 }

 FormElementKey::FormElementKey(AtomicStringImpl* name, AtomicStringImpl* type)
     : m_name(name), m_type(type)
 {
     ref();
 }

 FormElementKey::~FormElementKey()
 {
     deref();
 }

 FormElementKey::FormElementKey(const FormElementKey& other)
     : m_name(other.name()), m_type(other.type())
 {
     ref();
 }

 FormElementKey& FormElementKey::operator=(const FormElementKey& other)
 {
     other.ref();
     deref();
     m_name = other.name();
     m_type = other.type();
     return *this;
 }

 void FormElementKey::ref() const
 {
     if (name())
         name()->ref();
     if (type())
         type()->ref();
 }

 void FormElementKey::deref() const
 {
     if (name())
         name()->deref();
     if (type())
         type()->deref();
 }

 unsigned FormElementKeyHash::hash(const FormElementKey& k)
 {
     ASSERT(sizeof(k) % (sizeof(uint16_t) * 2) == 0);

     unsigned l = sizeof(k) / (sizeof(uint16_t) * 2);
     const uint16_t* s = reinterpret_cast<const uint16_t*>(&k);
     uint32_t hash = WTF::stringHashingStartValue;

     // Main loop
     for (; l > 0; l--) {
         hash += s[0];
         uint32_t tmp = (s[1] << 11) ^ hash;
         hash = (hash << 16) ^ tmp;
         s += 2;
         hash += hash >> 11;
     }

     // Force "avalanching" of final 127 bits
     hash ^= hash << 3;
     hash += hash >> 5;
     hash ^= hash << 2;
     hash += hash >> 15;
     hash ^= hash << 10;

     // this avoids ever returning a hash code of 0, since that is used to
     // signal "hash not computed yet", using a value that is likely to be
     // effectively the same as 0 when the low bits are masked
     if (hash == 0)
         hash = 0x80000000;

     return hash;
 }

 void Document::setIconURL(const String& iconURL, const String& type)
 {
     // FIXME - <rdar://problem/4727645> - At some point in the future, we might actually honor the "type"
     if (m_iconURL.isEmpty())
         m_iconURL = iconURL;
     else if (!type.isEmpty())
         m_iconURL = iconURL;
 }

 void Document::setUseSecureKeyboardEntryWhenActive(bool usesSecureKeyboard)
 {
     if (m_useSecureKeyboardEntryWhenActive == usesSecureKeyboard)
         return;

     m_useSecureKeyboardEntryWhenActive = usesSecureKeyboard;
     m_frame->updateSecureKeyboardEntryIfActive();
 }

 bool Document::useSecureKeyboardEntryWhenActive() const
 {
     return m_useSecureKeyboardEntryWhenActive;
 }

 void Document::initSecurityContext()
 {
     if (securityOrigin() && !securityOrigin()->isEmpty())
         return;  // m_securityOrigin has already been initialized.

     if (!m_frame) {
         // No source for a security context.
         // This can occur via document.implementation.createDocument().
         m_cookieURL = KURL("");
         ScriptExecutionContext::setSecurityOrigin(SecurityOrigin::createEmpty());
         return;
     }

     // In the common case, create the security context from the currently
     // loading URL.
     const KURL& url = m_frame->loader()->url();
     m_cookieURL = url;
     ScriptExecutionContext::setSecurityOrigin(SecurityOrigin::create(url));

     if (FrameLoader::allowSubstituteDataAccessToLocal()) {
         // If this document was loaded with substituteData, then the document can
         // load local resources.  See https://bugs.webkit.org/show_bug.cgi?id=16756
         // and https://bugs.webkit.org/show_bug.cgi?id=19760 for further
         // discussion.
         DocumentLoader* documentLoader = m_frame->loader()->documentLoader();
         if (documentLoader && documentLoader->substituteData().isValid())
             securityOrigin()->grantLoadLocalResources();
     }

     if (Settings* settings = this->settings()) {
         if (!settings->isWebSecurityEnabled()) {
           // Web security is turned off.  We should let this document access every
           // other document.  This is used primary by testing harnesses for web
           // sites.
           securityOrigin()->grantUniversalAccess();

         } else if (settings->allowUniversalAccessFromFileURLs() && securityOrigin()->isLocal()) {
           // Some clients want file:// URLs to have universal access, but that
           // setting is dangerous for other clients.
           securityOrigin()->grantUniversalAccess();
         }
     }

     if (!securityOrigin()->isEmpty())
         return;

     // If we do not obtain a meaningful origin from the URL, then we try to
     // find one via the frame hierarchy.

     Frame* ownerFrame = m_frame->tree()->parent();
     if (!ownerFrame)
         ownerFrame = m_frame->loader()->opener();

     if (ownerFrame) {
         m_cookieURL = ownerFrame->document()->cookieURL();
         // We alias the SecurityOrigins to match Firefox, see Bug 15313
         // https://bugs.webkit.org/show_bug.cgi?id=15313
         ScriptExecutionContext::setSecurityOrigin(ownerFrame->document()->securityOrigin());
     }
 }

 void Document::setSecurityOrigin(SecurityOrigin* securityOrigin)
 {
     ScriptExecutionContext::setSecurityOrigin(securityOrigin);
     // FIXME: Find a better place to enable DNS prefetch, which is a loader concept,
     // not applicable to arbitrary documents.
     initDNSPrefetch();
 }

 void Document::updateFocusAppearanceSoon()
 {
     if (!m_updateFocusAppearanceTimer.isActive())
         m_updateFocusAppearanceTimer.startOneShot(0);
 }

 void Document::cancelFocusAppearanceUpdate()
 {
     m_updateFocusAppearanceTimer.stop();
 }

 void Document::updateFocusAppearanceTimerFired(Timer<Document>*)
 {
     Node* node = focusedNode();
     if (!node)
         return;
     if (!node->isElementNode())
         return;

     updateLayout();

     Element* element = static_cast<Element*>(node);
     if (element->isFocusable())
         element->updateFocusAppearance(false);
 }

 void Document::executeScriptSoonTimerFired(Timer<Document>* timer)
 {
     ASSERT_UNUSED(timer, timer == &m_executeScriptSoonTimer);

     Vector<pair<ScriptElementData*, CachedResourceHandle<CachedScript> > > scripts;
     scripts.swap(m_scriptsToExecuteSoon);
     size_t size = scripts.size();
     for (size_t i = 0; i < size; ++i) {
         scripts[i].first->execute(scripts[i].second.get());
         scripts[i].first->element()->deref(); // Balances ref() in executeScriptSoon().
     }
 }

 void Document::executeScriptSoon(ScriptElementData* data, CachedResourceHandle<CachedScript> cachedScript)
 {
     ASSERT_ARG(data, data);

     Element* element = data->element();
     ASSERT(element);
     ASSERT(element->document() == this);
     ASSERT(element->inDocument());

     m_scriptsToExecuteSoon.append(make_pair(data, cachedScript));
     element->ref(); // Balanced by deref()s in executeScriptSoonTimerFired() and ~Document().
     if (!m_executeScriptSoonTimer.isActive())
         m_executeScriptSoonTimer.startOneShot(0);
 }

 // FF method for accessing the selection added for compatability.
 DOMSelection* Document::getSelection() const
 {
     return frame() ? frame()->domWindow()->getSelection() : 0;
 }

 #if ENABLE(DATABASE)

 void Document::addOpenDatabase(Database* database)
 {
     if (!m_openDatabaseSet)
         m_openDatabaseSet.set(new DatabaseSet);

     ASSERT(!m_openDatabaseSet->contains(database));
     m_openDatabaseSet->add(database);
 }

 void Document::removeOpenDatabase(Database* database)
 {
     ASSERT(m_openDatabaseSet && m_openDatabaseSet->contains(database));
     if (!m_openDatabaseSet)
         return;

     m_openDatabaseSet->remove(database);
 }

 DatabaseThread* Document::databaseThread()
 {
     if (!m_databaseThread && !m_hasOpenDatabases) {
         // Create the database thread on first request - but not if at least one database was already opened,
         // because in that case we already had a database thread and terminated it and should not create another.
         m_databaseThread = DatabaseThread::create();
         if (!m_databaseThread->start())
             m_databaseThread = 0;
     }

     return m_databaseThread.get();
 }

 void Document::stopDatabases()
 {
     if (m_openDatabaseSet) {
         DatabaseSet::iterator i = m_openDatabaseSet->begin();
         DatabaseSet::iterator end = m_openDatabaseSet->end();
         for (; i != end; ++i) {
             (*i)->stop();
             if (m_databaseThread)
                 m_databaseThread->unscheduleDatabaseTasks(*i);
         }
     }

     if (m_databaseThread)
         m_databaseThread->requestTermination();
 }

 #endif

 #if ENABLE(WML)
 void Document::resetWMLPageState()
 {
     if (WMLPageState* pageState = wmlPageStateForDocument(this))
         pageState->reset();
 }

 void Document::initializeWMLPageState()
 {
     if (!isWMLDocument())
         return;

     static_cast<WMLDocument*>(this)->initialize();
 }
 #endif

 void Document::attachRange(Range* range)
 {
     ASSERT(!m_ranges.contains(range));
     m_ranges.add(range);
 }

 void Document::detachRange(Range* range)
 {
     // We don't ASSERT m_ranges.contains(range) to allow us to call this
     // unconditionally to fix: https://bugs.webkit.org/show_bug.cgi?id=26044
     m_ranges.remove(range);
 }

 CanvasRenderingContext2D* Document::getCSSCanvasContext(const String& type, const String& name, int width, int height)
 {
     HTMLCanvasElement* result = getCSSCanvasElement(name);
     if (!result)
         return 0;
     result->setSize(IntSize(width, height));
     return result->getContext(type);
 }

 HTMLCanvasElement* Document::getCSSCanvasElement(const String& name)
 {
     RefPtr<HTMLCanvasElement> result = m_cssCanvasElements.get(name).get();
     if (!result) {
         result = new HTMLCanvasElement(canvasTag, this);
         m_cssCanvasElements.set(name, result);
     }
     return result.get();
 }

 void Document::initDNSPrefetch()
 {
     m_haveExplicitlyDisabledDNSPrefetch = false;
     m_isDNSPrefetchEnabled = securityOrigin()->protocol() == "http";

     // Inherit DNS prefetch opt-out from parent frame
     if (Document* parent = parentDocument()) {
         if (!parent->isDNSPrefetchEnabled())
             m_isDNSPrefetchEnabled = false;
     }
 }

 void Document::parseDNSPrefetchControlHeader(const String& dnsPrefetchControl)
 {
     if (equalIgnoringCase(dnsPrefetchControl, "on") && !m_haveExplicitlyDisabledDNSPrefetch) {
         m_isDNSPrefetchEnabled = true;
         return;
     }

     m_isDNSPrefetchEnabled = false;
     m_haveExplicitlyDisabledDNSPrefetch = true;
 }

 void Document::reportException(const String& errorMessage, int lineNumber, const String& sourceURL)
 {
     if (DOMWindow* window = domWindow())
         window->console()->addMessage(JSMessageSource, ErrorMessageLevel, errorMessage, lineNumber, sourceURL);
 }

 void Document::addMessage(MessageDestination destination, MessageSource source, MessageLevel level, const String& message, unsigned lineNumber, const String& sourceURL)
 {
     switch (destination) {
     case InspectorControllerDestination:
         if (page())
             page()->inspectorController()->addMessageToConsole(source, level, message, lineNumber, sourceURL);
         return;
     case ConsoleDestination:
         if (DOMWindow* window = domWindow())
             window->console()->addMessage(source, level, message, lineNumber, sourceURL);
         return;
     }
     ASSERT_NOT_REACHED();
 }

 void Document::resourceRetrievedByXMLHttpRequest(unsigned long identifier, const ScriptString& sourceString)
 {
     if (page())
         page()->inspectorController()->resourceRetrievedByXMLHttpRequest(identifier, sourceString);
     Frame* frame = this->frame();
     if (frame) {
         FrameLoader* frameLoader = frame->loader();
         frameLoader->didLoadResourceByXMLHttpRequest(identifier, sourceString);
     }
 }

 void Document::scriptImported(unsigned long identifier, const String& sourceString)
 {
     if (page())
         page()->inspectorController()->scriptImported(identifier, sourceString);
 }

 class ScriptExecutionContextTaskTimer : public TimerBase {
 public:
     ScriptExecutionContextTaskTimer(PassRefPtr<Document> context, PassRefPtr<ScriptExecutionContext::Task> task)
         : m_context(context)
         , m_task(task)
     {
     }

 private:
     virtual void fired()
     {
         m_task->performTask(m_context.get());
         delete this;
     }

     RefPtr<Document> m_context;
     RefPtr<ScriptExecutionContext::Task> m_task;
 };

 struct PerformTaskContext {
     PerformTaskContext(ScriptExecutionContext* scriptExecutionContext, PassRefPtr<ScriptExecutionContext::Task> task)
         : scriptExecutionContext(scriptExecutionContext)
         , task(task)
     {
     }

     ScriptExecutionContext* scriptExecutionContext; // The context should exist until task execution.
     RefPtr<ScriptExecutionContext::Task> task;
 };

 static void performTask(void* ctx)
 {
     PerformTaskContext* ptctx = reinterpret_cast<PerformTaskContext*>(ctx);
     ptctx->task->performTask(ptctx->scriptExecutionContext);
     delete ptctx;
 }

 void Document::postTask(PassRefPtr<Task> task)
 {
     if (isMainThread()) {
         ScriptExecutionContextTaskTimer* timer = new ScriptExecutionContextTaskTimer(static_cast<Document*>(this), task);
         timer->startOneShot(0);
     } else {
         callOnMainThread(performTask, new PerformTaskContext(this, task));
     }
 }

 Element* Document::findAnchor(const String& name)
 {
     if (name.isEmpty())
         return 0;
     if (Element* element = getElementById(name))
         return element;
     for (Node* node = this; node; node = node->traverseNextNode()) {
         if (node->hasTagName(aTag)) {
             HTMLAnchorElement* anchor = static_cast<HTMLAnchorElement*>(node);
             if (inCompatMode()) {
                 // Quirks mode, case insensitive comparison of names.
                 if (equalIgnoringCase(anchor->name(), name))
                     return anchor;
             } else {
                 // Strict mode, names need to match exactly.
                 if (anchor->name() == name)
                     return anchor;
             }
         }
     }
     return 0;
 }

 String Document::displayStringModifiedByEncoding(const String& str) const
 {
     if (m_decoder)
         return m_decoder->encoding().displayString(str.impl());
     return str;
 }

 PassRefPtr<StringImpl> Document::displayStringModifiedByEncoding(PassRefPtr<StringImpl> str) const
 {
     if (m_decoder)
         return m_decoder->encoding().displayString(str);
     return str;
 }

 void Document::displayBufferModifiedByEncoding(UChar* buffer, unsigned len) const
 {
     if (m_decoder)
         m_decoder->encoding().displayBuffer(buffer, len);
 }

 #if ENABLE(XHTMLMP)
 bool Document::isXHTMLMPDocument() const
 {
     if (!frame() || !frame()->loader())
         return false;
     // As per section 7.2 of OMA-WAP-XHTMLMP-V1_1-20061020-A.pdf, a conforming user agent
     // MUST accept XHTMLMP document identified as "application/vnd.wap.xhtml+xml"
     // and SHOULD accept it identified as "application/xhtml+xml"
     return frame()->loader()->responseMIMEType() == "application/vnd.wap.xhtml+xml" || frame()->loader()->responseMIMEType() == "application/xhtml+xml";
 }
 #endif

 } // namespace WebCore