Refactoring: Make LinkStyle instantiation lazy

Source/core/html/HTMLLinkElement.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 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
@@ skipping 45 matching lines @@
 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_link(adoptPtr(new LinkStyle(this)))
     , m_linkLoader(this)
     , m_sizes(DOMSettableTokenList::create())
     , m_createdByParser(createdByParser)
     , m_isInShadowTree(false)
     , m_beforeLoadRecurseCount(0)
 {
     ASSERT(hasTagName(linkTag));
     ScriptWrappable::init(this);
 }
 
@@ skipping 21 matching lines @@
         process();
     } else if (name == typeAttr) {
         m_type = value;
         process();
     } else if (name == sizesAttr) {
         setSizes(value);
         process();
     } else if (name == mediaAttr) {
         m_media = value.string().lower();
         process();
-    } else if (name == disabledAttr)
-        m_link->setDisabledState(!value.isNull());
-    else if (name == onbeforeloadAttr)
+    } else if (name == disabledAttr) {
+        if (LinkStyle* link = linkStyle())
+            link->setDisabledState(!value.isNull());
+    } else if (name == onbeforeloadAttr)
         setAttributeEventListener(eventNames().beforeloadEvent, createAttributeEventListener(this, name, value));
     else {
-        if (name == titleAttr)
-            m_link->setSheetTitle(value);
+        if (name == titleAttr) {
+            if (LinkStyle* link = linkStyle())
+                link->setSheetTitle(value);
+        }
+
         HTMLElement::parseAttribute(name, value);
     }
 }
 
 bool HTMLLinkElement::shouldLoadLink()
 {
     bool continueLoad = true;
     RefPtr<Document> originalDocument = document();
     int recursionRank = ++m_beforeLoadRecurseCount;
     if (!dispatchBeforeLoadEvent(getNonEmptyURLAttribute(hrefAttr)))
         continueLoad = false;
 
     // A beforeload handler might have removed us from the document or changed the document.
     if (continueLoad && (!inDocument() || document() != originalDocument))
         continueLoad = false;
 
     // If the beforeload handler recurses into the link element by mutating it, we should only
     // let the latest (innermost) mutation occur.
     if (recursionRank != m_beforeLoadRecurseCount)
         continueLoad = false;
 
     if (recursionRank == 1)
         m_beforeLoadRecurseCount = 0;
 
     return continueLoad;
 }
 
-bool HTMLLinkElement::shouldProcessStyle()
+LinkStyle* HTMLLinkElement::linkStyleToProcess()
 {
-    bool should = inDocument() && !m_isInShadowTree;
-    ASSERT(should || !m_link->hasSheet());
-    return should;
+    bool visible = inDocument() && !m_isInShadowTree;
+    if (!visible) {
+        ASSERT(!linkStyle() || !linkStyle()->hasSheet());
+        return 0;
+    }
+
+    if (!m_link) {
+        m_link = adoptPtr(new LinkStyle(this));
+        if (fastHasAttribute(disabledAttr))
+            m_link->setDisabledState(true);
+    }
+
+    return m_link.get();
 }
 
 void HTMLLinkElement::process()
 {
-    if (shouldProcessStyle())
-        m_link->process();
+    if (LinkStyle* link = linkStyleToProcess())
+        link->process();
 }
 
 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_link->hasSheet());
+        ASSERT(!linkStyle() || !linkStyle()->hasSheet());
         return;
     }
     document()->styleSheetCollection()->removeStyleSheetCandidateNode(this);
 
-    m_link->ownerRemoved();
+    if (LinkStyle* link = linkStyle())
+        link->ownerRemoved();
 
     if (document()->renderer())
         document()->styleResolverChanged(DeferRecalcStyle);
 }
 
 void HTMLLinkElement::finishParsingChildren()
 {
     m_createdByParser = false;
     HTMLElement::finishParsingChildren();
 }
 
 bool HTMLLinkElement::styleSheetIsLoading() const
 {
-    return m_link->styleSheetIsLoading();
+    return linkStyle() && linkStyle()->styleSheetIsLoading();
 }
 
 void HTMLLinkElement::linkLoaded()
 {
     dispatchEvent(Event::create(eventNames().loadEvent, false, false));
 }
 
 void HTMLLinkElement::linkLoadingErrored()
 {
     dispatchEvent(Event::create(eventNames().errorEvent, false, false));
@@ skipping 14 matching lines @@
     dispatchEvent(Event::create(eventNames().webkitprerenderloadEvent, false, false));
 }
 
 void HTMLLinkElement::didSendDOMContentLoadedForLinkPrerender()
 {
     dispatchEvent(Event::create(eventNames().webkitprerenderdomcontentloadedEvent, false, false));
 }
 
 bool HTMLLinkElement::sheetLoaded()
 {
-    return m_link->sheetLoaded();
+    ASSERT(linkStyle());
+    return linkStyle()->sheetLoaded();
 }
 
 void HTMLLinkElement::notifyLoadedSheetAndAllCriticalSubresources(bool errorOccurred)
 {
-    m_link->notifyLoadedSheetAndAllCriticalSubresources(errorOccurred);
+    ASSERT(linkStyle());
+    linkStyle()->notifyLoadedSheetAndAllCriticalSubresources(errorOccurred);
 }
 
 void HTMLLinkElement::dispatchPendingLoadEvents()
 {
     linkLoadEventSender().dispatchPendingEvents();
 }
 
 void HTMLLinkElement::dispatchPendingEvent(LinkEventSender* eventSender)
 {
     ASSERT_UNUSED(eventSender, eventSender == &linkLoadEventSender());
-    if (m_link->hasLoadedSheet())
+    ASSERT(linkStyle());
+    if (linkStyle()->hasLoadedSheet())
         linkLoaded();
     else
         linkLoadingErrored();
 }
 
 void HTMLLinkElement::startLoadingDynamicSheet()
 {
-    m_link->startLoadingDynamicSheet();
+    ASSERT(linkStyle());
+    linkStyle()->startLoadingDynamicSheet();
 }
 
 bool HTMLLinkElement::isURLAttribute(const Attribute& attribute) const
 {
     return attribute.name().localName() == hrefAttr || HTMLElement::isURLAttribute(attribute);
 }
 
 KURL HTMLLinkElement::href() const
 {
     return document()->completeURL(getAttribute(hrefAttr));
@@ skipping 303 matching lines @@
 void LinkStyle::ownerRemoved()
 {
     if (m_sheet)
         clearSheet();
 
     if (styleSheetIsLoading())
         removePendingSheet(RemovePendingSheetNotifyLater);
 }
 
 } // namespace WebCore