/*
 * 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 Apple 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., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */

#include "config.h"
#include "Document.h"

#include "AXObjectCache.h"
#include "CDATASection.h"
#include "CSSStyleSheet.h"
#include "CSSValueKeywords.h"
#include "Comment.h"
#include "DOMImplementation.h"
#include "DocLoader.h"
#include "DocumentFragment.h"
#include "DocumentLoader.h"
#include "DocumentType.h"
#include "EditingText.h"
#include "Editor.h"
#include "EditorClient.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 "HitTestRequest.h"
#include "HitTestResult.h"
#include "HTMLBodyElement.h"
#include "HTMLDocument.h"
#include "HTMLElementFactory.h"
#include "HTMLFrameOwnerElement.h"
#include "HTMLHeadElement.h"
#include "HTMLImageLoader.h"
#include "HTMLInputElement.h"
#include "HTMLLinkElement.h"
#include "HTMLMapElement.h"
#include "HTMLNameCollection.h"
#include "HTMLNames.h"
#include "HTMLStyleElement.h"
#include "HTMLTitleElement.h"
#include "HTTPParsers.h"
#include "JSEditor.h"
#include "KeyboardEvent.h"
#include "Logging.h"
#include "MouseEvent.h"
#include "MouseEventWithHitTestResults.h"
#include "MutationEvent.h"
#include "NameNodeList.h"
#include "NodeFilter.h"
#include "NodeIterator.h"
#include "OverflowEvent.h"
#include "Page.h"
#include "PlatformKeyboardEvent.h"
#include "ProcessingInstruction.h"
#include "RegisteredEventListener.h"
#include "RegularExpression.h"
#include "RenderArena.h"
#include "RenderView.h"
#include "RenderWidget.h"
#include "SegmentedString.h"
#include "SelectionController.h"
#include "Settings.h"
#include "StringHash.h"
#include "StyleSheetList.h"
#include "SystemTime.h"
#include "TextEvent.h"
#include "TextIterator.h"
#include "TextResourceDecoder.h"
#include "TreeWalker.h"
#include "UIEvent.h"
#include "WheelEvent.h"
#include "XMLTokenizer.h"
#include "csshelper.h"
#include "cssstyleselector.h"
#include "kjs_binding.h"
#include "kjs_proxy.h"
#include "xmlhttprequest.h"

#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"
#include "TimeScheduler.h"
#endif

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

namespace WebCore {

using namespace EventNames;
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);

// Golden ratio - arbitrary start value to avoid mapping all 0's to all 0's
static const unsigned PHI = 0x9e3779b9U;

// 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());
}

DeprecatedPtrList<Document>*  Document::changedDocuments = 0;

// FrameView might be 0
Document::Document(DOMImplementation* impl, Frame* frame)
    : ContainerNode(0)
    , m_implementation(impl)
    , m_domtree_version(0)
    , m_styleSheets(new StyleSheetList)
    , m_title("")
    , m_titleSetExplicitly(false)
    , m_imageLoadEventTimer(this, &Document::imageLoadEventTimerFired)
#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
    , m_hasDashboardRegions(false)
    , m_dashboardRegionsDirty(false)
    , m_accessKeyMapValid(false)
    , m_createRenderers(true)
    , m_inPageCache(false)
    , m_isAllowedToLoadLocalResources(false)
    , m_useSecureKeyboardEntryWhenActive(false)
#if USE(LOW_BANDWIDTH_DISPLAY)
    , m_inLowBandwidthDisplay(false)
#endif    
{
    m_document.resetSkippingRef(this);

    m_printing = false;

    m_frame = frame;
    m_renderArena = 0;

    m_axObjectCache = 0;
    
    // FIXME: DocLoader probably no longer needs the frame argument
    m_docLoader = new DocLoader(frame, this);

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

    pMode = Strict;
    hMode = XHtml;
    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_styleSelector = new CSSStyleSelector(this, m_usersheet, m_styleSheets.get(), !inCompatMode());
    m_didCalculateStyleSelector = false;
    m_pendingStylesheets = 0;
    m_ignorePendingStylesheets = false;
    m_pendingSheetLayout = NoLayoutWithPendingSheets;

    m_cssTarget = 0;

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

    m_processingLoadEvent = false;
    m_startTime = currentTime();
    m_overMinimumLayoutThreshold = false;
    
    m_jsEditor = 0;

    static int docID = 0;
    m_docID = docID++;
}

void Document::removedLastRef()
{
    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;
    } else
        delete this;
}

Document::~Document()
{
    ASSERT(!renderer());
    ASSERT(!m_inPageCache);
    ASSERT(!m_savedRenderer);

    removeAllEventListeners();

#if ENABLE(SVG)
    delete m_svgExtensions;
#endif

    XMLHttpRequest::detachRequests(this);
    {
        KJS::JSLock lock;
        KJS::ScriptInterpreter::forgetAllDOMNodesForDocument(this);
    }

    if (m_docChanged && changedDocuments)
        changedDocuments->remove(this);
    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);

    if (m_axObjectCache) {
        delete m_axObjectCache;
        m_axObjectCache = 0;
    }
    m_decoder = 0;
    
    if (m_jsEditor) {
        delete m_jsEditor;
        m_jsEditor = 0;
    }
    
    deleteAllValues(m_selectedRadioButtons);
}

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)
{
    m_docType = docType;
}

DocumentType *Document::doctype() const
{
    return m_docType.get();
}

DOMImplementation* Document::implementation() const
{
    return m_implementation.get();
}

void Document::childrenChanged()
{
    // invalidate the document element we have cached in case it was replaced
    m_documentElement = 0;
}

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

    return m_documentElement.get();
}

PassRefPtr<Element> Document::createElement(const String &name, ExceptionCode& ec)
{
    String lowerName(name.lower());
    if (!isValidName(lowerName)) {
        ec = INVALID_CHARACTER_ERR;
        return 0;
    }
    return HTMLElementFactory::createHTMLElement(AtomicString(lowerName), this, 0, 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 new CSSMutableStyleDeclaration;
}

PassRefPtr<Node> Document::importNode(Node* importedNode, bool deep, ExceptionCode& ec)
{
    ec = 0;
    
    if (!importedNode
#if ENABLE(SVG)
        || (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 != 0)
                return 0;

            NamedAttrMap* 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 != 0)
                        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 != 0)
                        return 0;
                    newElement->appendChild(newChild.release(), ec);
                    if (ec != 0)
                        return 0;
                }
            }

            return newElement.release();
        }
        case ATTRIBUTE_NODE:
        case ENTITY_NODE:
        case DOCUMENT_NODE:
        case DOCUMENT_TYPE_NODE:
        case DOCUMENT_FRAGMENT_NODE:
        case NOTATION_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;
    }
    
    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->m_attrWasSpecifiedOrElementHasRareData = 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;
}

// FIXME: This should really be in a possible ElementFactory class
PassRefPtr<Element> Document::createElement(const QualifiedName& qName, bool createdByParser, ExceptionCode& ec)
{
    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.localName(), this, 0, createdByParser);
#if ENABLE(SVG)
    else if (qName.namespaceURI() == SVGNames::svgNamespaceURI)
        e = SVGElementFactory::createSVGElement(qName, this, createdByParser);
#endif
    
    if (!e)
        e = new Element(qName, document());
    
    if (e && !qName.prefix().isNull()) {
        e->setPrefix(qName.prefix(), ec);
        if (ec)
            return 0;
    }    
    
    return e.release();
}

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

    RefPtr<Element> e;
    QualifiedName qName = QualifiedName(AtomicString(prefix), AtomicString(localName), AtomicString(_namespaceURI));
    
    return createElement(qName, false, ec);
}

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

    Element *element = m_elementsById.get(elementId.impl());
    if (element)
        return element;
        
    if (m_duplicateIds.contains(elementId.impl())) {
        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;
                }
            }
        }
    }
    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::inputEncoding() const
{
    if (TextResourceDecoder* d = decoder())
        return d->encoding().name();
    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)
{
    // FIXME: also raise NOT_SUPPORTED_ERR if the version is set to a value that is not supported by this Document.
    if (!implementation()->hasFeature("XML", String())) {
        ec = NOT_SUPPORTED_ERR;
        return;
    }
   
    m_xmlVersion = version;
}

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

    m_xmlStandalone = standalone;
}

String Document::documentURI() const
{
    return m_baseURL;
}

void Document::setDocumentURI(const String &uri)
{
    m_baseURL = uri.deprecatedString();
}

String Document::baseURI() const
{
    return documentURI();
}

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

    HitTestRequest request(true, true);
    HitTestResult result(IntPoint(x, y));
    renderer()->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)
{
    if (!m_elementsById.contains(elementId.impl()))
        m_elementsById.set(elementId.impl(), element);
    else
        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()) {
                ExceptionCode ec = 0;
                m_titleElement = createElement("title", ec);
                ASSERT(!ec);
                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;
}

Frame* Document::frame() const 
{
    return m_frame; 
}

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 new Range(this);
}

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

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

void Document::setDocumentChanged(bool b)
{
    if (b) {
        if (!m_docChanged) {
            if (!changedDocuments)
                changedDocuments = new DeprecatedPtrList<Document>;
            changedDocuments->append(this);
        }
        if (m_accessKeyMapValid) {
            m_accessKeyMapValid = false;
            m_elementsByAccessKey.clear();
        }
    } else {
        if (m_docChanged && changedDocuments)
            changedDocuments->remove(this);
    }

    m_docChanged = b;
}

void Document::recalcStyle(StyleChange change)
{
    if (m_inStyleRecalc)
        return; // Guard against re-entrancy. -dwh
        
    m_inStyleRecalc = true;
    
    ASSERT(!renderer() || renderArena());
    if (!renderer() || !renderArena())
        goto bail_out;

    if (change == Force) {
        RenderStyle* oldStyle = renderer()->style();
        if (oldStyle)
            oldStyle->ref();
        RenderStyle* _style = new (m_renderArena) RenderStyle();
        _style->ref();
        _style->setDisplay(BLOCK);
        _style->setVisuallyOrdered(visuallyOrdered);
        // ### make the font stuff _really_ work!!!!

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

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

        StyleChange ch = diff(_style, oldStyle);
        if (renderer() && ch != NoChange)
            renderer()->setStyle(_style);
        if (change != Force)
            change = ch;

        _style->deref(m_renderArena);
        if (oldStyle)
            oldStyle->deref(m_renderArena);
    }

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

    if (changed() && view())
        view()->layout();

bail_out:
    setChanged(NoStyleChange);
    setHasChangedChild(false);
    setDocumentChanged(false);
    
    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::updateRendering()
{
    if (hasChangedChild())
        recalcStyle(NoChange);
}

void Document::updateDocumentsRendering()
{
    if (!changedDocuments)
        return;

    while (Document* doc = changedDocuments->take()) {
        doc->m_docChanged = false;
        doc->updateRendering();
    }
}

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

    // FIXME: Dave Hyatt's pretty sure we can remove this because layout calls recalcStyle as needed.
    updateRendering();

    // 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();    
    }

    updateLayout();

    m_ignorePendingStylesheets = oldIgnore;
}

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

    if (!m_renderArena)
        m_renderArena = new RenderArena();
    
    // Create the rendering tree
    setRenderer(new (m_renderArena) RenderView(this, view()));

    recalcStyle(Force);

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

    ContainerNode::attach();

    setRenderer(render);
}

void Document::detach()
{
    RenderObject* render = renderer();

    // indicate destruction mode,  i.e. attached() but renderer == 0
    setRenderer(0);
    
    if (m_inPageCache) {
        if (render)
            axObjectCache()->remove(render);
        return;
    }

    // Empty out these lists as a performance optimization, since detaching
    // all the individual render objects will cause all the RenderImage
    // objects to remove themselves from the lists.
    m_imageLoadEventDispatchSoonList.clear();
    m_imageLoadEventDispatchingList.clear();
    
    m_hoverNode = 0;
    m_focusedNode = 0;
    m_activeNode = 0;

    ContainerNode::detach();

    if (render)
        render->destroy();

    // FIXME: is this needed or desirable?
    m_frame = 0;
    
    if (m_renderArena) {
        delete m_renderArena;
        m_renderArena = 0;
    }
}

void Document::removeAllEventListenersFromAllNodes()
{
    m_windowEventListeners.clear();
    removeAllDisconnectedNodeEventListeners();
    for (Node *n = this; n; n = n->traverseNextNode()) {
        if (!n->isEventTargetNode())
            continue;
        EventTargetNodeCast(n)->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)
        EventTargetNodeCast(*i)->removeAllEventListeners();
    m_disconnectedNodesWithEventListeners.clear();
}

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.
        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;
    return m_axObjectCache;
}

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

void Document::updateSelection()
{
    if (!renderer())
        return;
    
    RenderView *canvas = static_cast<RenderView*>(renderer());
    Selection selection = frame()->selectionController()->selection();
        
    if (!selection.isRange())
        canvas->clearSelection();
    else {
        // Use the rightmost candidate for the start of the selection, and the leftmost candidate for the end of the selection.
        // Example: foo <a>bar</a>.  Imagine that a line wrap occurs after 'foo', and that 'bar' is selected.   If we pass [foo, 3]
        // as the start of the selection, the selection painting code will think that content on the line containing 'foo' is selected
        // and will fill the gap before 'bar'.
        Position startPos = selection.visibleStart().deepEquivalent();
        if (startPos.downstream().isCandidate())
            startPos = startPos.downstream();
        Position endPos = selection.visibleEnd().deepEquivalent();
        if (endPos.upstream().isCandidate())
            endPos = endPos.upstream();
        
        // We can get into a state where the selection endpoints map to the same VisiblePosition when a selection is deleted
        // because we don't yet notify the SelectionController of text removal.
        if (startPos.isNotNull() && endPos.isNotNull() && selection.visibleStart() != selection.visibleEnd()) {
            RenderObject *startRenderer = startPos.node()->renderer();
            RenderObject *endRenderer = endPos.node()->renderer();
            static_cast<RenderView*>(renderer())->setSelection(startRenderer, startPos.offset(), endRenderer, endPos.offset());
        }
    }
}

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

void Document::open()
{
    // This is work that we should probably do in clear(), but we can't have it
    // happen when implicitOpen() is called unless we reorganize Frame code.
    if (Document *parent = parentDocument()) {
        setURL(parent->baseURL());
        setBaseURL(parent->baseURL());
    }

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

    implicitOpen();

    if (frame())
        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);
}

HTMLElement* Document::body()
{
    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 = i;
    }
    return static_cast<HTMLElement*>(body);
}

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;

    // Create a body element if we don't already have one. See Radar 3758785.
    if (!this->body() && isHTMLDocument()) {
        if (Node* documentElement = this->documentElement()) {
            ExceptionCode ec = 0;
            documentElement->appendChild(new HTMLBodyElement(this), ec);
            ASSERT(!ec);
        }
    }
    
    dispatchImageLoadEventsNow();
    this->dispatchWindowEvent(loadEvent, false, false);
    if (Frame* f = frame())
        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();

    // Now do our painting/layout, but only if we aren't in a subframe or if we're in a subframe
    // that has been sized already.  Otherwise, our view size would be incorrect, so doing any 
    // layout/painting now would be pointless.
    if (!ownerElement() || (ownerElement()->renderer() && !ownerElement()->renderer()->needsLayout())) {
        updateRendering();
        
        // Always do a layout after loading if needed.
        if (view() && renderer() && (!renderer()->firstChild() || renderer()->needsLayout()))
            view()->layout();
            
        // Paint immediately after the document is ready.  We do this to ensure that any timers set by the
        // onload don't have a chance to fire before we would have painted.  To avoid over-flushing we only
        // worry about this for the top-level document.
#if !PLATFORM(MAC)
        // FIXME: This causes a timing issue with the dispatchDidFinishLoad delegate callback.
        // See <rdar://problem/5092361>
        if (view() && !ownerElement())
            view()->update();
#endif
    }

#if PLATFORM(MAC)
    if (renderer() && AXObjectCache::accessibilityEnabled())
        axObjectCache()->postNotificationToElement(renderer(), "AXLoadComplete");
#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()
{
    // We can update layout if:
    // (a) we actually need a layout
    // (b) our stylesheets are all loaded
    // (c) we have a <body>
    return (renderer() && renderer()->needsLayout() && haveStylesheetsLoaded() &&
            documentElement() && documentElement()->renderer() &&
            (!documentElement()->hasTagName(htmlTag) || body()));
}

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 DeprecatedString& text)
{
    write(String(text));
}

void Document::write(const String& text)
{
#ifdef INSTRUMENT_LAYOUT_SCHEDULING
    if (!ownerElement())
        printf("Beginning a document.write at %d\n", elapsedTime());
#endif
    
    if (!m_tokenizer) {
        open();
        ASSERT(m_tokenizer);
        if (!m_tokenizer)
            return;
        write(DeprecatedString("<html>"));
    }
    m_tokenizer->write(text, false);
    
#ifdef INSTRUMENT_LAYOUT_SCHEDULING
    if (!ownerElement())
        printf("Ending a document.write at %d\n", elapsedTime());
#endif    
}

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

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();

    m_windowEventListeners.clear();
}

void Document::setURL(const DeprecatedString& url)
{
    if (url == m_url)
        return;

    m_url = url;
    if (m_styleSelector)
        m_styleSelector->setEncodedURL(m_url);

    m_isAllowedToLoadLocalResources = shouldBeAllowedToLoadLocalResources();
 }
 
bool Document::shouldBeAllowedToLoadLocalResources() const
{
    if (FrameLoader::shouldTreatURLAsLocal(m_url))
        return true;

    Frame* frame = this->frame();
    if (!frame)
        return false;
    
    DocumentLoader* documentLoader = frame->loader()->documentLoader();
    if (!documentLoader)
        return false;

    if (m_url == "about:blank" && frame->loader()->opener() && frame->loader()->opener()->document()->isAllowedToLoadLocalResources())
        return true;
    
    return documentLoader->substituteData().isValid();
}

void Document::setBaseURL(const DeprecatedString& baseURL) 
{ 
    m_baseURL = baseURL; 
    if (m_elemSheet)
        m_elemSheet->setHref(m_baseURL);
}

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

    updateStyleSelector();
}

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

CSSStyleSheet* Document::elementSheet()
{
    if (!m_elemSheet)
        m_elemSheet = new CSSStyleSheet(this, baseURL());
    return m_elemSheet.get();
}

void Document::determineParseMode(const String&)
{
    // For XML documents use strict parse mode.
    // HTML overrides this method to determine the parse mode.
    pMode = Strict;
    hMode = XHtml;
}

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) {
        // 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;
    }

    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().url();
            else
                url = completeURL(url);
            frame->loader()->scheduleRedirection(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);
    }
}

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);
    renderer()->layer()->hitTest(request, result);

    if (!request.readonly)
        updateRendering();

    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->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::stylesheetLoaded()
{
    // 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();
}

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

    DeprecatedPtrList<StyleSheet> oldStyleSheets = m_styleSheets->styleSheets;
    m_styleSheets->styleSheets.clear();
    Node *n;
    for (n = this; n; n = n->traverseNextNode()) {
        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("");
                    Node *c;
                    for (c = elem->firstChild(); c; c = c->nextSibling()) {
                        if (c->nodeType() == TEXT_NODE || c->nodeType() == CDATA_SECTION_NODE)
                            sheetText += c->nodeValue();
                    }

                    CSSStyleSheet *cssSheet = new CSSStyleSheet(this);
                    cssSheet->parseString(sheetText);
                    pi->setCSSStyleSheet(cssSheet);
                    sheet = cssSheet;
                }
            }

        } 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);
            DeprecatedString title = e->getAttribute(titleAttr).deprecatedString();
            bool enabledViaScript = false;
            if (e->hasLocalName(linkTag)) {
                // <LINK> element
                HTMLLinkElement* l = static_cast<HTMLLinkElement*>(n);
                if (l->isLoading() || l->isDisabled())
                    continue;
                if (!l->sheet())
                    title = DeprecatedString::null;
                enabledViaScript = l->isEnabledViaScript();
            }

            // 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.
                    DeprecatedString rel = e->getAttribute(relAttr).deprecatedString();
                    if (e->hasLocalName(styleTag) || !rel.contains("alternate"))
                        m_preferredStylesheetSet = m_selectedStylesheetSet = title;
                }
                
                if (title != m_preferredStylesheetSet)
                    sheet = 0;

#if ENABLE(SVG)
                if (!n->isHTMLElement())
                    title = title.replace('&', "&&");
#endif
            }
        }

        if (sheet) {
            sheet->ref();
            m_styleSheets->styleSheets.append(sheet);
        }
    
        // For HTML documents, stylesheets are not allowed within/after the <BODY> tag. So we
        // can stop searching here.
        if (isHTMLDocument() && n->hasTagName(bodyTag))
            break;
    }

    // De-reference all the stylesheets in the old list
    DeprecatedPtrListIterator<StyleSheet> it(oldStyleSheets);
    for (; it.current(); ++it)
        it.current()->deref();

    // Create a new style selector
    delete m_styleSelector;
    String usersheet = m_usersheet;
    if (view() && view()->mediaType() == "print")
        usersheet += m_printSheet;
    m_styleSelector = new CSSStyleSelector(this, usersheet, m_styleSheets.get(), !inCompatMode());
    m_styleSelector->setEncodedURL(m_url);
    m_didCalculateStyleSelector = true;
}

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

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

void Document::focusedNodeRemoved(Node* node)
{
    setFocusedNode(0);
}

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();
}

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

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

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;
        
    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->isTextArea() || r->isTextField()) && r->isEdited()) {
            EventTargetNodeCast(oldFocusedNode.get())->dispatchHTMLEvent(changeEvent, true, false);
            if ((r = static_cast<RenderObject*>(oldFocusedNode.get()->renderer())))
                r->setEdited(false);
        }

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

        if (m_focusedNode) {
            // handler shifted focus
            focusChangeBlocked = true;
            newFocusedNode = 0;
        }
        EventTargetNodeCast(oldFocusedNode.get())->dispatchUIEvent(DOMFocusOutEvent);
        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)
        EventTargetNodeCast(m_focusedNode.get())->dispatchFocusEvent();

        if (m_focusedNode != newFocusedNode) {
            // handler shifted focus
            focusChangeBlocked = true;
            goto SetFocusedNodeDone;
        }
        EventTargetNodeCast(m_focusedNode.get())->dispatchUIEvent(DOMFocusInEvent);
        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)
    if (!focusChangeBlocked && m_focusedNode && AXObjectCache::accessibilityEnabled())
        axObjectCache()->handleFocusedUIElementChanged();
#endif

SetFocusedNodeDone:
    updateRendering();
    return !focusChangeBlocked;
  }
  
void Document::setCSSTarget(Node* n)
{
    if (m_cssTarget)
        m_cssTarget->setChanged();
    m_cssTarget = n;
    if (n)
        n->setChanged();
}

Node* Document::getCSSTarget() const
{
    return m_cssTarget;
}

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

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

void Document::notifyBeforeNodeRemoval(Node *n)
{
    if (Frame* f = frame()) {
        f->selectionController()->nodeWillBeRemoved(n);
        f->dragCaretController()->nodeWillBeRemoved(n);
    }

    HashSet<NodeIterator*>::const_iterator end = m_nodeIterators.end();
    for (HashSet<NodeIterator*>::const_iterator it = m_nodeIterators.begin(); it != end; ++it)
        (*it)->notifyBeforeNodeRemoval(n);
}

DOMWindow* Document::defaultView() const
{
    if (!frame())
        return 0;
    
    return frame()->domWindow();
}

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

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

void Document::handleWindowEvent(Event *evt, bool useCapture)
{
    if (m_windowEventListeners.isEmpty())
        return;
        
    // if any html event listeners are registered on the window, then dispatch them here
    RegisteredEventListenerList listenersCopy = m_windowEventListeners;
    RegisteredEventListenerList::iterator it = listenersCopy.begin();
    
    for (; it != listenersCopy.end(); ++it)
        if ((*it)->eventType() == evt->type() && (*it)->useCapture() == useCapture && !(*it)->removed()) 
            (*it)->listener()->handleEvent(evt, true);
}


void Document::defaultEventHandler(Event *evt)
{
    // handle accesskey
    if (evt->type() == keydownEvent) {
        KeyboardEvent* kevt = static_cast<KeyboardEvent *>(evt);
        if (kevt->ctrlKey()) {
            const PlatformKeyboardEvent* ev = kevt->keyEvent();
            String key = (ev ? ev->unmodifiedText() : kevt->keyIdentifier()).lower();
            Element* elem = getElementByAccessKey(key);
            if (elem) {
                elem->accessKeyAction(false);
                evt->setDefaultHandled();
                return;
            }
        }
    }

    ContainerNode::defaultEventHandler(evt);
}

void Document::setHTMLWindowEventListener(const AtomicString &eventType, PassRefPtr<EventListener> listener)
{
    // If we already have it we don't want removeWindowEventListener to delete it
    removeHTMLWindowEventListener(eventType);
    if (listener)
        addWindowEventListener(eventType, listener, false);
}

EventListener *Document::getHTMLWindowEventListener(const AtomicString &eventType)
{
    RegisteredEventListenerList::iterator it = m_windowEventListeners.begin();
       for (; it != m_windowEventListeners.end(); ++it)
        if ( (*it)->eventType() == eventType && (*it)->listener()->isHTMLEventListener())
            return (*it)->listener();
    return 0;
}

void Document::removeHTMLWindowEventListener(const AtomicString &eventType)
{
    RegisteredEventListenerList::iterator it = m_windowEventListeners.begin();
    for (; it != m_windowEventListeners.end(); ++it)
        if ( (*it)->eventType() == eventType && (*it)->listener()->isHTMLEventListener()) {
            m_windowEventListeners.remove(it);
            return;
        }
}

void Document::addWindowEventListener(const AtomicString &eventType, PassRefPtr<EventListener> listener, bool useCapture)
{
    // Remove existing identical listener set with identical arguments.
    // The DOM 2 spec says that "duplicate instances are discarded" in this case.
    removeWindowEventListener(eventType, listener.get(), useCapture);
    m_windowEventListeners.append(new RegisteredEventListener(eventType, listener, useCapture));
}

void Document::removeWindowEventListener(const AtomicString &eventType, EventListener *listener, bool useCapture)
{
    RegisteredEventListener rl(eventType, listener, useCapture);
    RegisteredEventListenerList::iterator it = m_windowEventListeners.begin();
    for (; it != m_windowEventListeners.end(); ++it)
        if (*(*it) == rl) {
            m_windowEventListeners.remove(it);
            return;
        }
}

bool Document::hasWindowEventListener(const AtomicString &eventType)
{
    RegisteredEventListenerList::iterator it = m_windowEventListeners.begin();
    for (; it != m_windowEventListeners.end(); ++it)
        if ((*it)->eventType() == eventType) {
            return true;
        }
    return false;
}

PassRefPtr<EventListener> Document::createHTMLEventListener(const String& functionName, const String& code, Node *node)
{
    if (Frame* frm = frame())
        if (KJSProxy* proxy = frm->scriptProxy())
            return proxy->createHTMLEventHandler(functionName, code, node);
    return 0;
}

void Document::setHTMLWindowEventListener(const AtomicString& eventType, Attribute* attr)
{
    setHTMLWindowEventListener(eventType,
        createHTMLEventListener(attr->localName().domString(), attr->value(), 0));
}

void Document::dispatchImageLoadEventSoon(HTMLImageLoader *image)
{
    m_imageLoadEventDispatchSoonList.append(image);
    if (!m_imageLoadEventTimer.isActive())
        m_imageLoadEventTimer.startOneShot(0);
}

void Document::removeImage(HTMLImageLoader* image)
{
    // Remove instances of this image from both lists.
    // Use loops because we allow multiple instances to get into the lists.
    while (m_imageLoadEventDispatchSoonList.removeRef(image)) { }
    while (m_imageLoadEventDispatchingList.removeRef(image)) { }
    if (m_imageLoadEventDispatchSoonList.isEmpty())
        m_imageLoadEventTimer.stop();
}

void Document::dispatchImageLoadEventsNow()
{
    // need to avoid re-entering this function; if new dispatches are
    // scheduled before the parent finishes processing the list, they
    // will set a timer and eventually be processed
    if (!m_imageLoadEventDispatchingList.isEmpty()) {
        return;
    }

    m_imageLoadEventTimer.stop();
    
    m_imageLoadEventDispatchingList = m_imageLoadEventDispatchSoonList;
    m_imageLoadEventDispatchSoonList.clear();
    for (DeprecatedPtrListIterator<HTMLImageLoader> it(m_imageLoadEventDispatchingList); it.current();) {
        HTMLImageLoader* image = it.current();
        // Must advance iterator *before* dispatching call.
        // Otherwise, it might be advanced automatically if dispatching the call had a side effect
        // of destroying the current HTMLImageLoader, and then we would advance past the *next* item,
        // missing one altogether.
        ++it;
        image->dispatchLoadEvent();
    }
    m_imageLoadEventDispatchingList.clear();
}

void Document::imageLoadEventTimerFired(Timer<Document>*)
{
    dispatchImageLoadEventsNow();
}

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

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

String Document::domain() const
{
    if (m_domain.isEmpty()) // not set yet (we set it on demand to save time and space)
        m_domain = KURL(URL()).host(); // Initially set to the host
    return m_domain;
}

void Document::setDomain(const String &newDomain, bool force /*=false*/)
{
    if (force) {
        m_domain = newDomain;
        return;
    }
    if (m_domain.isEmpty()) // not set yet (we set it on demand to save time and space)
        m_domain = KURL(URL()).host(); // Initially set to the host

    // Both NS and IE specify that changing the domain is only allowed when
    // the new domain is a suffix of the old domain.
    int oldLength = m_domain.length();
    int newLength = newDomain.length();
    if (newLength < oldLength) // e.g. newDomain=kde.org (7) and m_domain=www.kde.org (11)
    {
        String test = m_domain.copy();
        if (test[oldLength - newLength - 1] == '.') // Check that it's a subdomain, not e.g. "de.org"
        {
            test.remove(0, oldLength - newLength); // now test is "kde.org" from m_domain
            if (test == newDomain)                 // and we check that it's the same thing as newDomain
                m_domain = newDomain;
        }
    }
}

bool Document::isValidName(const String &name)
{
    const UChar* s = reinterpret_cast<const UChar*>(name.characters());
    unsigned length = name.length();

    if (length == 0)
        return false;

    unsigned i = 0;

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

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

    return true;
}

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

    if (length == 0)
        return false;

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

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

    if (!sawColon) {
        prefix = String();
        localName = qualifiedName.copy();
    } else {
        prefix = qualifiedName.substring(0, colonPos);
        localName = qualifiedName.substring(colonPos + 1, length - (colonPos + 1));
    }

    return true;
}

void Document::addImageMap(HTMLMapElement* imageMap)
{
    // 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(imageMap->getName().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();
    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 = hMode == XHtml ? name : name.lower();
    return m_imageMapsByName.get(mapName.impl());
}

void Document::setDecoder(TextResourceDecoder *decoder)
{
    m_decoder = decoder;
}

UChar Document::backslashAsCurrencySymbol() const
{
    if (!m_decoder)
        return '\\';
    return m_decoder->encoding().backslashAsCurrencySymbol();
}

DeprecatedString Document::completeURL(const DeprecatedString& URL)
{
    // FIXME: This treats null URLs the same as empty URLs, unlike the String function below.

    // If both the URL and base URL are empty, like they are for documents
    // created using DOMImplementation::createDocument, just return the passed in URL.
    // (We do this because URL() returns "about:blank" for empty URLs.
    if (m_url.isEmpty() && m_baseURL.isEmpty())
        return URL;
    if (!m_decoder)
        return KURL(baseURL(), URL).url();
    return KURL(baseURL(), URL, m_decoder->encoding()).url();
}

String Document::completeURL(const String &URL)
{
    // FIXME: This always returns null when passed a null URL, unlike the String function above.
    if (URL.isNull())
        return URL;
    return completeURL(URL.deprecatedString());
}

bool Document::inPageCache()
{
    return m_inPageCache;
}

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();
    } else {
        ASSERT(renderer() == 0 || renderer() == m_savedRenderer);
        ASSERT(m_renderArena);
        setRenderer(m_savedRenderer);
        m_savedRenderer = 0;
    }
}

void Document::registerForDidRestoreFromCacheCallback(Element* e)
{
    m_didRestorePageCallbackSet.add(e);
}

void Document::unregisterForDidRestoreFromCacheCallback(Element* e)
{
    m_didRestorePageCallbackSet.remove(e);
}

void Document::didRestoreFromCache()
{
    HashSet<Element*>::iterator it = m_didRestorePageCallbackSet.begin();
    for (; it != m_didRestorePageCallbackSet.end(); ++it) 
        (*it)->didRestoreFromCache();
}

void Document::secureFormAdded()
{
    m_secureForms++;
}

void Document::secureFormRemoved()
{
    ASSERT(m_secureForms > 0);
    m_secureForms--;
}

bool Document::hasSecureForm() const
{
    return m_secureForms > 0;
}

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

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

String Document::toString() const
{
    String result;

    for (Node *child = firstChild(); child != NULL; child = child->nextSibling()) {
        result += child->toString();
    }

    return result;
}

// Support for Javascript execCommand, and related methods

JSEditor *Document::jsEditor()
{
    if (!m_jsEditor)
        m_jsEditor = new JSEditor(this);
    return m_jsEditor;
}

bool Document::execCommand(const String &command, bool userInterface, const String &value)
{
    return jsEditor()->execCommand(command, userInterface, value);
}

bool Document::queryCommandEnabled(const String &command)
{
    return jsEditor()->queryCommandEnabled(command);
}

bool Document::queryCommandIndeterm(const String &command)
{
    return jsEditor()->queryCommandIndeterm(command);
}

bool Document::queryCommandState(const String &command)
{
    return jsEditor()->queryCommandState(command);
}

bool Document::queryCommandSupported(const String &command)
{
    return jsEditor()->queryCommandSupported(command);
}

String Document::queryCommandValue(const String &command)
{
    return jsEditor()->queryCommandValue(command);
}

static IntRect placeholderRectForMarker(void)
{
    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};
        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* pastEndNode = range->pastEndNode();
    for (Node* node = range->startNode(); node != pastEndNode; 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 location.
// They do not overlap each other, as currently required by the drawing code in RenderText.cpp.

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;
        ASSERT(markers.size() == rects.size());
        size_t i;
        for (i = 0; i != markers.size();) {
            DocumentMarker marker = markers[i];
            
            if (newMarker.endOffset < marker.startOffset+1) {
                // This is the first marker that is completely after newMarker, and disjoint from it.
                // We found our insertion point.
                break;
            } else if (newMarker.startOffset > marker.endOffset) {
                // maker is before newMarker, and disjoint from it.  Keep scanning.
                i++;
            } else if (newMarker == marker) {
                // already have this one, NOP
                return;
            } else {
                // marker and newMarker intersect or touch - merge them into newMarker
                newMarker.startOffset = min(newMarker.startOffset, marker.startOffset);
                newMarker.endOffset = max(newMarker.endOffset, marker.endOffset);
                // remove old one, we'll add newMarker later
                markers.remove(i);
                rects.remove(i);
                // it points to the next marker to consider
            }
        }
        // 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();
}

#if ENABLE(XSLT)

void Document::applyXSLTransform(ProcessingInstruction* pi)
{
    RefPtr<XSLTProcessor> processor = new XSLTProcessor;
    processor->setXSLStylesheet(static_cast<XSLStyleSheet*>(pi->sheet()));
    
    DeprecatedString resultMIMEType;
    DeprecatedString newSource;
    DeprecatedString 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::createAttributeNS(const String &namespaceURI, const String &qualifiedName, ExceptionCode& ec)
{
    if (qualifiedName.isNull()) {
        ec = NAMESPACE_ERR;
        return 0;
    }

    String localName = qualifiedName;
    String prefix;
    int colonpos;
    if ((colonpos = qualifiedName.find(':')) >= 0) {
        prefix = qualifiedName.copy();
        localName = qualifiedName.copy();
        prefix.truncate(colonpos);
        localName.remove(0, colonpos+1);
    }

    if (!isValidName(localName)) {
        ec = INVALID_CHARACTER_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, new MappedAttribute(QualifiedName(prefix, localName, namespaceURI), StringImpl::empty()));
}

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

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

void Document::radioButtonChecked(HTMLInputElement *caller, HTMLFormElement *form)
{
    // Without a name, there is no group.
    if (caller->name().isEmpty())
        return;
    if (!form)
        form = defaultForm;
    // Uncheck the currently selected item
    NameToInputMap* formRadioButtons = m_selectedRadioButtons.get(form);
    if (!formRadioButtons) {
        formRadioButtons = new NameToInputMap;
        m_selectedRadioButtons.set(form, formRadioButtons);
    }
    
    HTMLInputElement* currentCheckedRadio = formRadioButtons->get(caller->name().impl());
    if (currentCheckedRadio && currentCheckedRadio != caller)
        currentCheckedRadio->setChecked(false);

    formRadioButtons->set(caller->name().impl(), caller);
}

HTMLInputElement* Document::checkedRadioButtonForGroup(AtomicStringImpl* name, HTMLFormElement *form)
{
    if (!form)
        form = defaultForm;
    NameToInputMap* formRadioButtons = m_selectedRadioButtons.get(form);
    if (!formRadioButtons)
        return 0;
    
    return formRadioButtons->get(name);
}

void Document::removeRadioButtonGroup(AtomicStringImpl* name, HTMLFormElement *form)
{
    if (!form)
        form = defaultForm;
    NameToInputMap* formRadioButtons = m_selectedRadioButtons.get(form);
    if (formRadioButtons) {
        formRadioButtons->remove(name);
        if (formRadioButtons->isEmpty()) {
            m_selectedRadioButtons.remove(form);
            delete formRadioButtons;
        }
    }
}

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

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

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

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

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

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

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

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

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

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

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

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

HTMLCollection::CollectionInfo* Document::nameCollectionInfo(HTMLCollection::Type type, const String& name)
{
    HashMap<AtomicStringImpl*, HTMLCollection::CollectionInfo>& map = m_nameCollectionInfo[type - HTMLCollection::UnnamedCollectionTypes];
    
    AtomicString atomicName(name);
    
    HashMap<AtomicStringImpl*, HTMLCollection::CollectionInfo>::iterator iter = map.find(atomicName.impl());
    if (iter == map.end())
        iter = map.add(atomicName.impl(), HTMLCollection::CollectionInfo()).first;
    
    return &iter->second;
}

PassRefPtr<NameNodeList> Document::getElementsByName(const String &elementName)
{
    return new NameNodeList(this, elementName);
}

void Document::finishedParsing()
{
    setParsing(false);
    if (Frame* f = frame())
        f->loader()->finishedParsing();
}

Vector<String> Document::formElementsState() const
{
    Vector<String> stateVector;
    stateVector.reserveCapacity(m_formElementsWithState.size() * 3);
    typedef ListHashSet<HTMLGenericFormElement*>::const_iterator Iterator;
    Iterator end = m_formElementsWithState.end();
    for (Iterator it = m_formElementsWithState.begin(); it != end; ++it) {
        HTMLGenericFormElement* e = *it;
        stateVector.append(e->name().domString());
        stateVector.append(e->type().domString());
        stateVector.append(e->stateValue());
    }
    return stateVector;
}

#if ENABLE(XPATH)

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

PassRefPtr<XPathNSResolver> Document::createNSResolver(Node* nodeResolver)
{
    if (!m_xpathEvaluator)
        m_xpathEvaluator = new XPathEvaluator;
    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 = new XPathEvaluator;
    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() != HashTraits<AtomicStringImpl*>::deletedValue())
        name()->ref();
    if (type())
        type()->ref();
}

void FormElementKey::deref() const
{
    if (name() && name() != HashTraits<AtomicStringImpl*>::deletedValue())
        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 = PHI;

    // 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;
}

FormElementKey FormElementKeyHashTraits::deletedValue()
{
    return HashTraits<AtomicStringImpl*>::deletedValue();
}


String Document::iconURL()
{
    return m_iconURL;
}

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;
}

}