Move CSSRuleList to the garbage collected heap

Source/core/dom/StyleEngine.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2008, 2009, 2011, 2012 Google Inc. All rights reserved.
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) Research In Motion Limited 2010-2011. All rights reserved.
@@ skipping 83 matching lines @@
     , m_ignorePendingStylesheets(false)
     , m_didCalculateResolver(false)
     // We don't need to create CSSFontSelector for imported document or
     // HTMLTemplateElement's document, because those documents have no frame.
     , m_fontSelector(document.frame() ? CSSFontSelector::create(&document) : nullptr)
 {
 }
 
 StyleEngine::~StyleEngine()
 {
+}
+
+void StyleEngine::detachFromDocument()
+{
+    // Cleanup is performed eagerly when the StyleEngine is removed from the
+    // document. The StyleEngine is unreachable after this, since only the
+    // document has a reference to it.
     for (unsigned i = 0; i < m_injectedAuthorStyleSheets.size(); ++i)
         m_injectedAuthorStyleSheets[i]->clearOwnerNode();
     for (unsigned i = 0; i < m_authorStyleSheets.size(); ++i)
         m_authorStyleSheets[i]->clearOwnerNode();
 
     if (m_fontSelector) {
         m_fontSelector->clearDocument();
         if (m_resolver)
             m_fontSelector->unregisterForInvalidationCallbacks(m_resolver.get());
     }
+
+    // Decrement reference counts for things we could be keeping alive.
+    m_fontSelector.clear();
+    m_resolver.clear();
+    m_styleSheetCollectionMap.clear();
 }
 
 inline Document* StyleEngine::master()
 {
     if (isMaster())
         return &m_document;
     HTMLImport* import = m_document.import();
     if (!import) // Document::import() can return null while executing its destructor.
         return 0;
     return import->master();
@@ skipping 41 matching lines @@
 {
     if (treeScope == m_document)
         return &m_documentStyleSheetCollection;
 
     HashMap<TreeScope*, OwnPtr<TreeScopeStyleSheetCollection> >::iterator it = m_styleSheetCollectionMap.find(&treeScope);
     if (it == m_styleSheetCollectionMap.end())
         return 0;
     return it->value.get();
 }
 
-const Vector<RefPtr<StyleSheet> >& StyleEngine::styleSheetsForStyleSheetList(TreeScope& treeScope)
+const WillBeHeapVector<RefPtrWillBeMember<StyleSheet> >& StyleEngine::styleSheetsForStyleSheetList(TreeScope& treeScope)
 {
     if (treeScope == m_document)
         return m_documentStyleSheetCollection.styleSheetsForStyleSheetList();
 
     return ensureStyleSheetCollectionFor(treeScope)->styleSheetsForStyleSheetList();
 }
 
-const Vector<RefPtr<CSSStyleSheet> >& StyleEngine::activeAuthorStyleSheets() const
+const WillBeHeapVector<RefPtrWillBeMember<CSSStyleSheet> >& StyleEngine::activeAuthorStyleSheets() const
 {
     return m_documentStyleSheetCollection.activeAuthorStyleSheets();
 }
 
 void StyleEngine::combineCSSFeatureFlags(const RuleFeatureSet& features)
 {
     // Delay resetting the flags until after next style recalc since unapplying the style may not work without these set (this is true at least with before/after).
     m_usesSiblingRules = m_usesSiblingRules || features.usesSiblingRules();
     m_usesFirstLineRules = m_usesFirstLineRules || features.usesFirstLineRules();
     m_maxDirectAdjacentSelectors = max(m_maxDirectAdjacentSelectors, features.maxDirectAdjacentSelectors());
 }
 
 void StyleEngine::resetCSSFeatureFlags(const RuleFeatureSet& features)
 {
     m_usesSiblingRules = features.usesSiblingRules();
     m_usesFirstLineRules = features.usesFirstLineRules();
     m_maxDirectAdjacentSelectors = features.maxDirectAdjacentSelectors();
 }
 
-const Vector<RefPtr<CSSStyleSheet> >& StyleEngine::injectedAuthorStyleSheets() const
+const WillBeHeapVector<RefPtrWillBeMember<CSSStyleSheet> >& StyleEngine::injectedAuthorStyleSheets() const
 {
     updateInjectedStyleSheetCache();
     return m_injectedAuthorStyleSheets;
 }
 
 void StyleEngine::updateInjectedStyleSheetCache() const
 {
     if (m_injectedStyleSheetCacheValid)
         return;
     m_injectedStyleSheetCacheValid = true;
     m_injectedAuthorStyleSheets.clear();
 
     Page* owningPage = m_document.page();
     if (!owningPage)
         return;
 
     const InjectedStyleSheetEntryVector& entries = InjectedStyleSheets::instance().entries();
     for (unsigned i = 0; i < entries.size(); ++i) {
         const InjectedStyleSheetEntry* entry = entries[i].get();
         if (entry->injectedFrames() == InjectStyleInTopFrameOnly && m_document.ownerElement())
             continue;
         if (!URLPatternMatcher::matchesPatterns(m_document.url(), entry->whitelist()))
             continue;
-        RefPtr<CSSStyleSheet> groupSheet = CSSStyleSheet::createInline(const_cast<Document*>(&m_document), KURL());
+        RefPtrWillBeRawPtr<CSSStyleSheet> groupSheet = CSSStyleSheet::createInline(const_cast<Document*>(&m_document), KURL());
         m_injectedAuthorStyleSheets.append(groupSheet);
         groupSheet->contents()->parseString(entry->source());
     }
 }
 
 void StyleEngine::invalidateInjectedStyleSheetCache()
 {
     m_injectedStyleSheetCacheValid = false;
     markDocumentDirty();
     // FIXME: updateInjectedStyleSheetCache is called inside StyleSheetCollection::updateActiveStyleSheets
@@ skipping 121 matching lines @@
 void StyleEngine::clearMediaQueryRuleSetStyleSheets()
 {
     m_documentStyleSheetCollection.clearMediaQueryRuleSetStyleSheets();
     clearMediaQueryRuleSetOnTreeScopeStyleSheets(m_activeTreeScopes);
     clearMediaQueryRuleSetOnTreeScopeStyleSheets(m_dirtyTreeScopes);
 }
 
 void StyleEngine::updateStyleSheetsInImport(DocumentStyleSheetCollector& parentCollector)
 {
     ASSERT(!isMaster());
-    Vector<RefPtr<StyleSheet> > sheetsForList;
+    WillBeHeapVector<RefPtrWillBeMember<StyleSheet> > sheetsForList;
     ImportedDocumentStyleSheetCollector subcollector(parentCollector, sheetsForList);
     m_documentStyleSheetCollection.collectStyleSheets(this, subcollector);
     m_documentStyleSheetCollection.swapSheetsForSheetList(sheetsForList);
 }
 
 bool StyleEngine::updateActiveStyleSheets(StyleResolverUpdateMode updateMode)
 {
     ASSERT(isMaster());
     ASSERT(!m_document.inStyleRecalc());
 
@@ skipping 24 matching lines @@
 
     InspectorInstrumentation::activeStyleSheetsUpdated(&m_document);
     m_usesRemUnits = m_documentStyleSheetCollection.usesRemUnits();
 
     m_dirtyTreeScopes.clear();
     m_documentScopeDirty = false;
 
     return requiresFullStyleRecalc;
 }
 
-const Vector<RefPtr<StyleSheet> > StyleEngine::activeStyleSheetsForInspector() const
+const WillBeHeapVector<RefPtrWillBeMember<StyleSheet> > StyleEngine::activeStyleSheetsForInspector() const
 {
     if (m_activeTreeScopes.isEmpty())
         return m_documentStyleSheetCollection.styleSheetsForStyleSheetList();
 
-    Vector<RefPtr<StyleSheet> > activeStyleSheets;
+    WillBeHeapVector<RefPtrWillBeMember<StyleSheet> > activeStyleSheets;
 
     activeStyleSheets.appendVector(m_documentStyleSheetCollection.styleSheetsForStyleSheetList());
 
     TreeScopeSet::const_iterator begin = m_activeTreeScopes.begin();
     TreeScopeSet::const_iterator end = m_activeTreeScopes.end();
     for (TreeScopeSet::const_iterator it = begin; it != end; ++it) {
         if (TreeScopeStyleSheetCollection* collection = m_styleSheetCollectionMap.get(*it))
             activeStyleSheets.appendVector(collection->styleSheetsForStyleSheetList());
     }
 
@@ skipping 191 matching lines @@
 void StyleEngine::removeSheet(StyleSheetContents* contents)
 {
     WillBeHeapHashMap<RawPtrWillBeWeakMember<StyleSheetContents>, AtomicString>::iterator it = sheetToTextCache().find(contents);
     if (it == sheetToTextCache().end())
         return;
 
     textToSheetCache().remove(it->value);
     sheetToTextCache().remove(contents);
 }
 
+void StyleEngine::trace(Visitor* visitor)
+{
+    visitor->trace(m_injectedAuthorStyleSheets);
+    visitor->trace(m_authorStyleSheets);
 }
+
+}