Source/WebCore/html/HTMLLinkElement.cpp - platform/external/chromium_org/third_party/WebKit - Git at Google

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2003, 2006, 2007, 2008, 2009, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2009 Rob Buis (rwlbuis@gmail.com)
  * Copyright (C) 2011 Google Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Library General Public License for more details.
  *
  * You should have received a copy of the GNU Library General Public License
  * along with this library; see the file COPYING.LIB.  If not, write to
  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  * Boston, MA 02110-1301, USA.
  */

 #include "config.h"
 #include "HTMLLinkElement.h"

 #include "Attribute.h"
 #include "CachedCSSStyleSheet.h"
 #include "CachedResource.h"
 #include "CachedResourceLoader.h"
 #include "CachedResourceRequest.h"
 #include "Document.h"
 #include "DocumentStyleSheetCollection.h"
 #include "EventSender.h"
 #include "Frame.h"
 #include "FrameLoader.h"
 #include "FrameLoaderClient.h"
 #include "FrameTree.h"
 #include "FrameView.h"
 #include "HTMLNames.h"
 #include "HTMLParserIdioms.h"
 #include "MediaList.h"
 #include "MediaQueryEvaluator.h"
 #include "Page.h"
 #include "ScriptEventListener.h"
 #include "SecurityOrigin.h"
 #include "Settings.h"
 #include "StyleResolver.h"
 #include "StyleSheetContents.h"
 #include <wtf/StdLibExtras.h>

 namespace WebCore {

 using namespace HTMLNames;

 static LinkEventSender& linkLoadEventSender()
 {
     DEFINE_STATIC_LOCAL(LinkEventSender, sharedLoadEventSender, (eventNames().loadEvent));
     return sharedLoadEventSender;
 }

 inline HTMLLinkElement::HTMLLinkElement(const QualifiedName& tagName, Document* document, bool createdByParser)
     : HTMLElement(tagName, document)
     , m_linkLoader(this)
     , m_sizes(DOMSettableTokenList::create())
     , m_disabledState(Unset)
     , m_loading(false)
     , m_createdByParser(createdByParser)
     , m_isInShadowTree(false)
     , m_firedLoad(false)
     , m_loadedSheet(false)
     , m_pendingSheetType(None)
 {
     ASSERT(hasTagName(linkTag));
 }

 PassRefPtr<HTMLLinkElement> HTMLLinkElement::create(const QualifiedName& tagName, Document* document, bool createdByParser)
 {
     return adoptRef(new HTMLLinkElement(tagName, document, createdByParser));
 }

 HTMLLinkElement::~HTMLLinkElement()
 {
     if (m_sheet)
         m_sheet->clearOwnerNode();

     if (m_cachedSheet)
         m_cachedSheet->removeClient(this);

     if (inDocument())
         document()->styleSheetCollection()->removeStyleSheetCandidateNode(this);

     linkLoadEventSender().cancelEvent(this);
 }

 void HTMLLinkElement::setDisabledState(bool disabled)
 {
     DisabledState oldDisabledState = m_disabledState;
     m_disabledState = disabled ? Disabled : EnabledViaScript;
     if (oldDisabledState != m_disabledState) {
         // If we change the disabled state while the sheet is still loading, then we have to
         // perform three checks:
         if (styleSheetIsLoading()) {
             // Check #1: The sheet becomes disabled while loading.
             if (m_disabledState == Disabled)
                 removePendingSheet();

             // Check #2: An alternate sheet becomes enabled while it is still loading.
             if (m_relAttribute.m_isAlternate && m_disabledState == EnabledViaScript)
                 addPendingSheet(Blocking);

             // Check #3: A main sheet becomes enabled while it was still loading and
             // after it was disabled via script. It takes really terrible code to make this
             // happen (a double toggle for no reason essentially). This happens on
             // virtualplastic.net, which manages to do about 12 enable/disables on only 3
             // sheets. :)
             if (!m_relAttribute.m_isAlternate && m_disabledState == EnabledViaScript && oldDisabledState == Disabled)
                 addPendingSheet(Blocking);

             // If the sheet is already loading just bail.
             return;
         }

         // Load the sheet, since it's never been loaded before.
         if (!m_sheet && m_disabledState == EnabledViaScript)
             process();
         else
             document()->styleResolverChanged(DeferRecalcStyle); // Update the style selector.
     }
 }

 void HTMLLinkElement::parseAttribute(const Attribute& attribute)
 {
     if (attribute.name() == relAttr) {
         m_relAttribute = LinkRelAttribute(attribute.value());
         process();
     } else if (attribute.name() == hrefAttr) {
         String url = stripLeadingAndTrailingHTMLSpaces(attribute.value());
         m_url = url.isEmpty() ? KURL() : document()->completeURL(url);
         process();
     } else if (attribute.name() == typeAttr) {
         m_type = attribute.value();
         process();
     } else if (attribute.name() == sizesAttr) {
         setSizes(attribute.value());
         process();
     } else if (attribute.name() == mediaAttr) {
         m_media = attribute.value().string().lower();
         process();
     } else if (attribute.name() == disabledAttr)
         setDisabledState(!attribute.isNull());
     else if (attribute.name() == onbeforeloadAttr)
         setAttributeEventListener(eventNames().beforeloadEvent, createAttributeEventListener(this, attribute));
     else if (attribute.name() == onloadAttr)
         setAttributeEventListener(eventNames().loadEvent, createAttributeEventListener(this, attribute));
     else if (attribute.name() == onerrorAttr)
         setAttributeEventListener(eventNames().errorEvent, createAttributeEventListener(this, attribute));
     else {
         if (attribute.name() == titleAttr && m_sheet)
             m_sheet->setTitle(attribute.value());
         HTMLElement::parseAttribute(attribute);
     }
 }

 bool HTMLLinkElement::shouldLoadLink()
 {
     RefPtr<Document> originalDocument = document();
     if (!dispatchBeforeLoadEvent(m_url))
         return false;
     // A beforeload handler might have removed us from the document or changed the document.
     if (!inDocument() || document() != originalDocument)
         return false;
     return true;
 }

 void HTMLLinkElement::process()
 {
     if (!inDocument() || m_isInShadowTree) {
         ASSERT(!m_sheet);
         return;
     }

     String type = m_type.lower();

     if (!m_linkLoader.loadLink(m_relAttribute, type, m_sizes->toString(), m_url, document()))
         return;

     bool acceptIfTypeContainsTextCSS = document()->page() && document()->page()->settings() && document()->page()->settings()->treatsAnyTextCSSLinkAsStylesheet();

     if (m_disabledState != Disabled && (m_relAttribute.m_isStyleSheet || (acceptIfTypeContainsTextCSS && type.contains("text/css")))
         && document()->frame() && m_url.isValid()) {

         String charset = getAttribute(charsetAttr);
         if (charset.isEmpty() && document()->frame())
             charset = document()->charset();

         if (m_cachedSheet) {
             removePendingSheet();
             m_cachedSheet->removeClient(this);
             m_cachedSheet = 0;
         }

         if (!shouldLoadLink())
             return;

         m_loading = true;

         bool mediaQueryMatches = true;
         if (!m_media.isEmpty()) {
             RefPtr<RenderStyle> documentStyle = StyleResolver::styleForDocument(document());
             RefPtr<MediaQuerySet> media = MediaQuerySet::createAllowingDescriptionSyntax(m_media);
             MediaQueryEvaluator evaluator(document()->frame()->view()->mediaType(), document()->frame(), documentStyle.get());
             mediaQueryMatches = evaluator.eval(media.get());
         }

         // Don't hold up render tree construction and script execution on stylesheets
         // that are not needed for the rendering at the moment.
         bool blocking = mediaQueryMatches && !isAlternate();
         addPendingSheet(blocking ? Blocking : NonBlocking);

         // Load stylesheets that are not needed for the rendering immediately with low priority.
         ResourceLoadPriority priority = blocking ? ResourceLoadPriorityUnresolved : ResourceLoadPriorityVeryLow;
         CachedResourceRequest request(ResourceRequest(document()->completeURL(m_url)), charset, priority);
         m_cachedSheet = document()->cachedResourceLoader()->requestCSSStyleSheet(request);

         if (m_cachedSheet)
             m_cachedSheet->addClient(this);
         else {
             // The request may have been denied if (for example) the stylesheet is local and the document is remote.
             m_loading = false;
             removePendingSheet();
         }
     } else if (m_sheet) {
         // we no longer contain a stylesheet, e.g. perhaps rel or type was changed
         clearSheet();
         document()->styleResolverChanged(DeferRecalcStyle);
     }
 }

 void HTMLLinkElement::clearSheet()
 {
     ASSERT(m_sheet);
     ASSERT(m_sheet->ownerNode() == this);
     m_sheet->clearOwnerNode();
     m_sheet = 0;
 }

 Node::InsertionNotificationRequest HTMLLinkElement::insertedInto(ContainerNode* insertionPoint)
 {
     HTMLElement::insertedInto(insertionPoint);
     if (!insertionPoint->inDocument())
         return InsertionDone;

     m_isInShadowTree = isInShadowTree();
     if (m_isInShadowTree)
         return InsertionDone;

     document()->styleSheetCollection()->addStyleSheetCandidateNode(this, m_createdByParser);

     process();
     return InsertionDone;
 }

 void HTMLLinkElement::removedFrom(ContainerNode* insertionPoint)
 {
     HTMLElement::removedFrom(insertionPoint);
     if (!insertionPoint->inDocument())
         return;

     m_linkLoader.released();

     if (m_isInShadowTree) {
         ASSERT(!m_sheet);
         return;
     }
     document()->styleSheetCollection()->removeStyleSheetCandidateNode(this);

     if (m_sheet)
         clearSheet();

     if (styleSheetIsLoading())
         removePendingSheet(RemovePendingSheetNotifyLater);

     if (document()->renderer())
         document()->styleResolverChanged(DeferRecalcStyle);
 }

 void HTMLLinkElement::finishParsingChildren()
 {
     m_createdByParser = false;
     HTMLElement::finishParsingChildren();
 }

 void HTMLLinkElement::setCSSStyleSheet(const String& href, const KURL& baseURL, const String& charset, const CachedCSSStyleSheet* cachedStyleSheet)
 {
     if (!inDocument()) {
         ASSERT(!m_sheet);
         return;
     }
     // Completing the sheet load may cause scripts to execute.
     RefPtr<Node> protector(this);

     CSSParserContext parserContext(document(), baseURL, charset);

 #if ENABLE(PARSED_STYLE_SHEET_CACHING)
     if (RefPtr<StyleSheetContents> restoredSheet = const_cast<CachedCSSStyleSheet*>(cachedStyleSheet)->restoreParsedStyleSheet(parserContext)) {
         ASSERT(restoredSheet->isCacheable());
         ASSERT(!restoredSheet->isLoading());

         m_sheet = CSSStyleSheet::create(restoredSheet, this);
         m_sheet->setMediaQueries(MediaQuerySet::createAllowingDescriptionSyntax(m_media));
         m_sheet->setTitle(title());

         m_loading = false;
         sheetLoaded();
         notifyLoadedSheetAndAllCriticalSubresources(false);
         return;
     }
 #endif

     RefPtr<StyleSheetContents> styleSheet = StyleSheetContents::create(href, parserContext);

     m_sheet = CSSStyleSheet::create(styleSheet, this);
     m_sheet->setMediaQueries(MediaQuerySet::createAllowingDescriptionSyntax(m_media));
     m_sheet->setTitle(title());

     styleSheet->parseAuthorStyleSheet(cachedStyleSheet, document()->securityOrigin());

     m_loading = false;
     styleSheet->notifyLoadedSheet(cachedStyleSheet);
     styleSheet->checkLoaded();

 #if ENABLE(PARSED_STYLE_SHEET_CACHING)
     if (styleSheet->isCacheable())
         const_cast<CachedCSSStyleSheet*>(cachedStyleSheet)->saveParsedStyleSheet(styleSheet);
 #endif
 }

 bool HTMLLinkElement::styleSheetIsLoading() const
 {
     if (m_loading)
         return true;
     if (!m_sheet)
         return false;
     return m_sheet->contents()->isLoading();
 }

 void HTMLLinkElement::linkLoaded()
 {
     dispatchEvent(Event::create(eventNames().loadEvent, false, false));
 }

 void HTMLLinkElement::linkLoadingErrored()
 {
     dispatchEvent(Event::create(eventNames().errorEvent, false, false));
 }

 bool HTMLLinkElement::sheetLoaded()
 {
     if (!styleSheetIsLoading()) {
         removePendingSheet();
         return true;
     }
     return false;
 }

 void HTMLLinkElement::dispatchPendingLoadEvents()
 {
     linkLoadEventSender().dispatchPendingEvents();
 }

 void HTMLLinkElement::dispatchPendingEvent(LinkEventSender* eventSender)
 {
     ASSERT_UNUSED(eventSender, eventSender == &linkLoadEventSender());
     if (m_loadedSheet)
         linkLoaded();
     else
         linkLoadingErrored();
 }

 void HTMLLinkElement::notifyLoadedSheetAndAllCriticalSubresources(bool errorOccurred)
 {
     if (m_firedLoad)
         return;
     m_loadedSheet = !errorOccurred;
     linkLoadEventSender().dispatchEventSoon(this);
     m_firedLoad = true;
 }

 void HTMLLinkElement::startLoadingDynamicSheet()
 {
     // We don't support multiple blocking sheets.
     ASSERT(m_pendingSheetType < Blocking);
     addPendingSheet(Blocking);
 }

 bool HTMLLinkElement::isURLAttribute(const Attribute& attribute) const
 {
     return attribute.name() == hrefAttr || HTMLElement::isURLAttribute(attribute);
 }

 KURL HTMLLinkElement::href() const
 {
     return document()->completeURL(getAttribute(hrefAttr));
 }

 String HTMLLinkElement::rel() const
 {
     return getAttribute(relAttr);
 }

 String HTMLLinkElement::target() const
 {
     return getAttribute(targetAttr);
 }

 String HTMLLinkElement::type() const
 {
     return getAttribute(typeAttr);
 }

 IconType HTMLLinkElement::iconType() const
 {
     return m_relAttribute.m_iconType;
 }

 String HTMLLinkElement::iconSizes() const
 {
     return m_sizes->toString();
 }

 void HTMLLinkElement::addSubresourceAttributeURLs(ListHashSet<KURL>& urls) const
 {
     HTMLElement::addSubresourceAttributeURLs(urls);

     // Favicons are handled by a special case in LegacyWebArchive::create()
     if (m_relAttribute.m_iconType != InvalidIcon)
         return;

     if (!m_relAttribute.m_isStyleSheet)
         return;

     // Append the URL of this link element.
     addSubresourceURL(urls, href());

     // Walk the URLs linked by the linked-to stylesheet.
     if (CSSStyleSheet* styleSheet = const_cast<HTMLLinkElement*>(this)->sheet())
         styleSheet->contents()->addSubresourceStyleURLs(urls);
 }

 void HTMLLinkElement::addPendingSheet(PendingSheetType type)
 {
     if (type <= m_pendingSheetType)
         return;
     m_pendingSheetType = type;

     if (m_pendingSheetType == NonBlocking)
         return;
     document()->styleSheetCollection()->addPendingSheet();
 }

 void HTMLLinkElement::removePendingSheet(RemovePendingSheetNotificationType notification)
 {
     PendingSheetType type = m_pendingSheetType;
     m_pendingSheetType = None;

     if (type == None)
         return;
     if (type == NonBlocking) {
         // Document::removePendingSheet() triggers the style selector recalc for blocking sheets.
         document()->styleResolverChanged(RecalcStyleImmediately);
         return;
     }

     document()->styleSheetCollection()->removePendingSheet(
         notification == RemovePendingSheetNotifyImmediately
         ? DocumentStyleSheetCollection::RemovePendingSheetNotifyImmediately
         : DocumentStyleSheetCollection::RemovePendingSheetNotifyLater);
 }

 DOMSettableTokenList* HTMLLinkElement::sizes() const
 {
     return m_sizes.get();
 }

 void HTMLLinkElement::setSizes(const String& value)
 {
     m_sizes->setValue(value);
 }

 #if ENABLE(MICRODATA)
 String HTMLLinkElement::itemValueText() const
 {
     return getURLAttribute(hrefAttr);
 }

 void HTMLLinkElement::setItemValueText(const String& value, ExceptionCode&)
 {
     setAttribute(hrefAttr, value);
 }
 #endif

 } // namespace WebCore
	/*
	* Copyright (C) 1999 Lars Knoll (knoll@kde.org)
	* (C) 1999 Antti Koivisto (koivisto@kde.org)
	* (C) 2001 Dirk Mueller (mueller@kde.org)
	* Copyright (C) 2003, 2006, 2007, 2008, 2009, 2010 Apple Inc. All rights reserved.
	* Copyright (C) 2009 Rob Buis (rwlbuis@gmail.com)
	* Copyright (C) 2011 Google Inc. All rights reserved.
	*
	* This library is free software; you can redistribute it and/or
	* modify it under the terms of the GNU Library General Public
	* License as published by the Free Software Foundation; either
	* version 2 of the License, or (at your option) any later version.
	*
	* This library is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	* Library General Public License for more details.
	*
	* You should have received a copy of the GNU Library General Public License
	* along with this library; see the file COPYING.LIB. If not, write to
	* the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
	* Boston, MA 02110-1301, USA.
	*/

	#include "config.h"
	#include "HTMLLinkElement.h"

	#include "Attribute.h"
	#include "CachedCSSStyleSheet.h"
	#include "CachedResource.h"
	#include "CachedResourceLoader.h"
	#include "CachedResourceRequest.h"
	#include "Document.h"
	#include "DocumentStyleSheetCollection.h"
	#include "EventSender.h"
	#include "Frame.h"
	#include "FrameLoader.h"
	#include "FrameLoaderClient.h"
	#include "FrameTree.h"
	#include "FrameView.h"
	#include "HTMLNames.h"
	#include "HTMLParserIdioms.h"
	#include "MediaList.h"
	#include "MediaQueryEvaluator.h"
	#include "Page.h"
	#include "ScriptEventListener.h"
	#include "SecurityOrigin.h"
	#include "Settings.h"
	#include "StyleResolver.h"
	#include "StyleSheetContents.h"
	#include <wtf/StdLibExtras.h>

	namespace WebCore {

	using namespace HTMLNames;

	static LinkEventSender& linkLoadEventSender()
	{
	DEFINE_STATIC_LOCAL(LinkEventSender, sharedLoadEventSender, (eventNames().loadEvent));
	return sharedLoadEventSender;
	}

	inline HTMLLinkElement::HTMLLinkElement(const QualifiedName& tagName, Document* document, bool createdByParser)
	: HTMLElement(tagName, document)
	, m_linkLoader(this)
	, m_sizes(DOMSettableTokenList::create())
	, m_disabledState(Unset)
	, m_loading(false)
	, m_createdByParser(createdByParser)
	, m_isInShadowTree(false)
	, m_firedLoad(false)
	, m_loadedSheet(false)
	, m_pendingSheetType(None)
	{
	ASSERT(hasTagName(linkTag));
	}

	PassRefPtr<HTMLLinkElement> HTMLLinkElement::create(const QualifiedName& tagName, Document* document, bool createdByParser)
	{
	return adoptRef(new HTMLLinkElement(tagName, document, createdByParser));
	}

	HTMLLinkElement::~HTMLLinkElement()
	{
	if (m_sheet)
	m_sheet->clearOwnerNode();

	if (m_cachedSheet)
	m_cachedSheet->removeClient(this);

	if (inDocument())
	document()->styleSheetCollection()->removeStyleSheetCandidateNode(this);

	linkLoadEventSender().cancelEvent(this);
	}

	void HTMLLinkElement::setDisabledState(bool disabled)
	{
	DisabledState oldDisabledState = m_disabledState;
	m_disabledState = disabled ? Disabled : EnabledViaScript;
	if (oldDisabledState != m_disabledState) {
	// If we change the disabled state while the sheet is still loading, then we have to
	// perform three checks:
	if (styleSheetIsLoading()) {
	// Check #1: The sheet becomes disabled while loading.
	if (m_disabledState == Disabled)
	removePendingSheet();

	// Check #2: An alternate sheet becomes enabled while it is still loading.
	if (m_relAttribute.m_isAlternate && m_disabledState == EnabledViaScript)
	addPendingSheet(Blocking);

	// Check #3: A main sheet becomes enabled while it was still loading and
	// after it was disabled via script. It takes really terrible code to make this
	// happen (a double toggle for no reason essentially). This happens on
	// virtualplastic.net, which manages to do about 12 enable/disables on only 3
	// sheets. :)
	if (!m_relAttribute.m_isAlternate && m_disabledState == EnabledViaScript && oldDisabledState == Disabled)
	addPendingSheet(Blocking);

	// If the sheet is already loading just bail.
	return;
	}

	// Load the sheet, since it's never been loaded before.
	if (!m_sheet && m_disabledState == EnabledViaScript)
	process();
	else
	document()->styleResolverChanged(DeferRecalcStyle); // Update the style selector.
	}
	}

	void HTMLLinkElement::parseAttribute(const Attribute& attribute)
	{
	if (attribute.name() == relAttr) {
	m_relAttribute = LinkRelAttribute(attribute.value());
	process();
	} else if (attribute.name() == hrefAttr) {
	String url = stripLeadingAndTrailingHTMLSpaces(attribute.value());
	m_url = url.isEmpty() ? KURL() : document()->completeURL(url);
	process();
	} else if (attribute.name() == typeAttr) {
	m_type = attribute.value();
	process();
	} else if (attribute.name() == sizesAttr) {
	setSizes(attribute.value());
	process();
	} else if (attribute.name() == mediaAttr) {
	m_media = attribute.value().string().lower();
	process();
	} else if (attribute.name() == disabledAttr)
	setDisabledState(!attribute.isNull());
	else if (attribute.name() == onbeforeloadAttr)
	setAttributeEventListener(eventNames().beforeloadEvent, createAttributeEventListener(this, attribute));
	else if (attribute.name() == onloadAttr)
	setAttributeEventListener(eventNames().loadEvent, createAttributeEventListener(this, attribute));
	else if (attribute.name() == onerrorAttr)
	setAttributeEventListener(eventNames().errorEvent, createAttributeEventListener(this, attribute));
	else {
	if (attribute.name() == titleAttr && m_sheet)
	m_sheet->setTitle(attribute.value());
	HTMLElement::parseAttribute(attribute);
	}
	}

	bool HTMLLinkElement::shouldLoadLink()
	{
	RefPtr<Document> originalDocument = document();
	if (!dispatchBeforeLoadEvent(m_url))
	return false;
	// A beforeload handler might have removed us from the document or changed the document.
	if (!inDocument() \|\| document() != originalDocument)
	return false;
	return true;
	}

	void HTMLLinkElement::process()
	{
	if (!inDocument() \|\| m_isInShadowTree) {
	ASSERT(!m_sheet);
	return;
	}

	String type = m_type.lower();

	if (!m_linkLoader.loadLink(m_relAttribute, type, m_sizes->toString(), m_url, document()))
	return;

	bool acceptIfTypeContainsTextCSS = document()->page() && document()->page()->settings() && document()->page()->settings()->treatsAnyTextCSSLinkAsStylesheet();

	if (m_disabledState != Disabled && (m_relAttribute.m_isStyleSheet \|\| (acceptIfTypeContainsTextCSS && type.contains("text/css")))
	&& document()->frame() && m_url.isValid()) {

	String charset = getAttribute(charsetAttr);
	if (charset.isEmpty() && document()->frame())
	charset = document()->charset();

	if (m_cachedSheet) {
	removePendingSheet();
	m_cachedSheet->removeClient(this);
	m_cachedSheet = 0;
	}

	if (!shouldLoadLink())
	return;

	m_loading = true;

	bool mediaQueryMatches = true;
	if (!m_media.isEmpty()) {
	RefPtr<RenderStyle> documentStyle = StyleResolver::styleForDocument(document());
	RefPtr<MediaQuerySet> media = MediaQuerySet::createAllowingDescriptionSyntax(m_media);
	MediaQueryEvaluator evaluator(document()->frame()->view()->mediaType(), document()->frame(), documentStyle.get());
	mediaQueryMatches = evaluator.eval(media.get());
	}

	// Don't hold up render tree construction and script execution on stylesheets
	// that are not needed for the rendering at the moment.
	bool blocking = mediaQueryMatches && !isAlternate();
	addPendingSheet(blocking ? Blocking : NonBlocking);

	// Load stylesheets that are not needed for the rendering immediately with low priority.
	ResourceLoadPriority priority = blocking ? ResourceLoadPriorityUnresolved : ResourceLoadPriorityVeryLow;
	CachedResourceRequest request(ResourceRequest(document()->completeURL(m_url)), charset, priority);
	m_cachedSheet = document()->cachedResourceLoader()->requestCSSStyleSheet(request);

	if (m_cachedSheet)
	m_cachedSheet->addClient(this);
	else {
	// The request may have been denied if (for example) the stylesheet is local and the document is remote.
	m_loading = false;
	removePendingSheet();
	}
	} else if (m_sheet) {
	// we no longer contain a stylesheet, e.g. perhaps rel or type was changed
	clearSheet();
	document()->styleResolverChanged(DeferRecalcStyle);
	}
	}

	void HTMLLinkElement::clearSheet()
	{
	ASSERT(m_sheet);
	ASSERT(m_sheet->ownerNode() == this);
	m_sheet->clearOwnerNode();
	m_sheet = 0;
	}

	Node::InsertionNotificationRequest HTMLLinkElement::insertedInto(ContainerNode* insertionPoint)
	{
	HTMLElement::insertedInto(insertionPoint);
	if (!insertionPoint->inDocument())
	return InsertionDone;

	m_isInShadowTree = isInShadowTree();
	if (m_isInShadowTree)
	return InsertionDone;

	document()->styleSheetCollection()->addStyleSheetCandidateNode(this, m_createdByParser);

	process();
	return InsertionDone;
	}

	void HTMLLinkElement::removedFrom(ContainerNode* insertionPoint)
	{
	HTMLElement::removedFrom(insertionPoint);
	if (!insertionPoint->inDocument())
	return;

	m_linkLoader.released();

	if (m_isInShadowTree) {
	ASSERT(!m_sheet);
	return;
	}
	document()->styleSheetCollection()->removeStyleSheetCandidateNode(this);

	if (m_sheet)
	clearSheet();

	if (styleSheetIsLoading())
	removePendingSheet(RemovePendingSheetNotifyLater);

	if (document()->renderer())
	document()->styleResolverChanged(DeferRecalcStyle);
	}

	void HTMLLinkElement::finishParsingChildren()
	{
	m_createdByParser = false;
	HTMLElement::finishParsingChildren();
	}

	void HTMLLinkElement::setCSSStyleSheet(const String& href, const KURL& baseURL, const String& charset, const CachedCSSStyleSheet* cachedStyleSheet)
	{
	if (!inDocument()) {
	ASSERT(!m_sheet);
	return;
	}
	// Completing the sheet load may cause scripts to execute.
	RefPtr<Node> protector(this);

	CSSParserContext parserContext(document(), baseURL, charset);

	#if ENABLE(PARSED_STYLE_SHEET_CACHING)
	if (RefPtr<StyleSheetContents> restoredSheet = const_cast<CachedCSSStyleSheet*>(cachedStyleSheet)->restoreParsedStyleSheet(parserContext)) {
	ASSERT(restoredSheet->isCacheable());
	ASSERT(!restoredSheet->isLoading());

	m_sheet = CSSStyleSheet::create(restoredSheet, this);
	m_sheet->setMediaQueries(MediaQuerySet::createAllowingDescriptionSyntax(m_media));
	m_sheet->setTitle(title());

	m_loading = false;
	sheetLoaded();
	notifyLoadedSheetAndAllCriticalSubresources(false);
	return;
	}
	#endif

	RefPtr<StyleSheetContents> styleSheet = StyleSheetContents::create(href, parserContext);

	m_sheet = CSSStyleSheet::create(styleSheet, this);
	m_sheet->setMediaQueries(MediaQuerySet::createAllowingDescriptionSyntax(m_media));
	m_sheet->setTitle(title());

	styleSheet->parseAuthorStyleSheet(cachedStyleSheet, document()->securityOrigin());

	m_loading = false;
	styleSheet->notifyLoadedSheet(cachedStyleSheet);
	styleSheet->checkLoaded();

	#if ENABLE(PARSED_STYLE_SHEET_CACHING)
	if (styleSheet->isCacheable())
	const_cast<CachedCSSStyleSheet*>(cachedStyleSheet)->saveParsedStyleSheet(styleSheet);
	#endif
	}

	bool HTMLLinkElement::styleSheetIsLoading() const
	{
	if (m_loading)
	return true;
	if (!m_sheet)
	return false;
	return m_sheet->contents()->isLoading();
	}

	void HTMLLinkElement::linkLoaded()
	{
	dispatchEvent(Event::create(eventNames().loadEvent, false, false));
	}

	void HTMLLinkElement::linkLoadingErrored()
	{
	dispatchEvent(Event::create(eventNames().errorEvent, false, false));
	}

	bool HTMLLinkElement::sheetLoaded()
	{
	if (!styleSheetIsLoading()) {
	removePendingSheet();
	return true;
	}
	return false;
	}

	void HTMLLinkElement::dispatchPendingLoadEvents()
	{
	linkLoadEventSender().dispatchPendingEvents();
	}

	void HTMLLinkElement::dispatchPendingEvent(LinkEventSender* eventSender)
	{
	ASSERT_UNUSED(eventSender, eventSender == &linkLoadEventSender());
	if (m_loadedSheet)
	linkLoaded();
	else
	linkLoadingErrored();
	}

	void HTMLLinkElement::notifyLoadedSheetAndAllCriticalSubresources(bool errorOccurred)
	{
	if (m_firedLoad)
	return;
	m_loadedSheet = !errorOccurred;
	linkLoadEventSender().dispatchEventSoon(this);
	m_firedLoad = true;
	}

	void HTMLLinkElement::startLoadingDynamicSheet()
	{
	// We don't support multiple blocking sheets.
	ASSERT(m_pendingSheetType < Blocking);
	addPendingSheet(Blocking);
	}

	bool HTMLLinkElement::isURLAttribute(const Attribute& attribute) const
	{
	return attribute.name() == hrefAttr \|\| HTMLElement::isURLAttribute(attribute);
	}

	KURL HTMLLinkElement::href() const
	{
	return document()->completeURL(getAttribute(hrefAttr));
	}

	String HTMLLinkElement::rel() const
	{
	return getAttribute(relAttr);
	}

	String HTMLLinkElement::target() const
	{
	return getAttribute(targetAttr);
	}

	String HTMLLinkElement::type() const
	{
	return getAttribute(typeAttr);
	}

	IconType HTMLLinkElement::iconType() const
	{
	return m_relAttribute.m_iconType;
	}

	String HTMLLinkElement::iconSizes() const
	{
	return m_sizes->toString();
	}

	void HTMLLinkElement::addSubresourceAttributeURLs(ListHashSet<KURL>& urls) const
	{
	HTMLElement::addSubresourceAttributeURLs(urls);

	// Favicons are handled by a special case in LegacyWebArchive::create()
	if (m_relAttribute.m_iconType != InvalidIcon)
	return;

	if (!m_relAttribute.m_isStyleSheet)
	return;

	// Append the URL of this link element.
	addSubresourceURL(urls, href());

	// Walk the URLs linked by the linked-to stylesheet.
	if (CSSStyleSheet* styleSheet = const_cast<HTMLLinkElement*>(this)->sheet())
	styleSheet->contents()->addSubresourceStyleURLs(urls);
	}

	void HTMLLinkElement::addPendingSheet(PendingSheetType type)
	{
	if (type <= m_pendingSheetType)
	return;
	m_pendingSheetType = type;

	if (m_pendingSheetType == NonBlocking)
	return;
	document()->styleSheetCollection()->addPendingSheet();
	}

	void HTMLLinkElement::removePendingSheet(RemovePendingSheetNotificationType notification)
	{
	PendingSheetType type = m_pendingSheetType;
	m_pendingSheetType = None;

	if (type == None)
	return;
	if (type == NonBlocking) {
	// Document::removePendingSheet() triggers the style selector recalc for blocking sheets.
	document()->styleResolverChanged(RecalcStyleImmediately);
	return;
	}

	document()->styleSheetCollection()->removePendingSheet(
	notification == RemovePendingSheetNotifyImmediately
	? DocumentStyleSheetCollection::RemovePendingSheetNotifyImmediately
	: DocumentStyleSheetCollection::RemovePendingSheetNotifyLater);
	}

	DOMSettableTokenList* HTMLLinkElement::sizes() const
	{
	return m_sizes.get();
	}

	void HTMLLinkElement::setSizes(const String& value)
	{
	m_sizes->setValue(value);
	}

	#if ENABLE(MICRODATA)
	String HTMLLinkElement::itemValueText() const
	{
	return getURLAttribute(hrefAttr);
	}

	void HTMLLinkElement::setItemValueText(const String& value, ExceptionCode&)
	{
	setAttribute(hrefAttr, value);
	}
	#endif

	} // namespace WebCore