StyleResolver should update RuleSets lazily.

Source/core/css/resolver/StyleResolver.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 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,
@@ skipping 22 matching lines @@
 #include "core/css/SiblingTraversalStrategies.h"
 #include "core/css/resolver/MatchedPropertiesCache.h"
 #include "core/css/resolver/ScopedStyleResolver.h"
 #include "core/css/resolver/StyleBuilder.h"
 #include "core/css/resolver/StyleResolverIncludes.h"
 #include "core/css/resolver/StyleResolverState.h"
 #include "core/css/resolver/StyleResourceLoader.h"
 #include "wtf/Deque.h"
 #include "wtf/HashMap.h"
 #include "wtf/HashSet.h"
+#include "wtf/ListHashSet.h"
 #include "wtf/RefPtr.h"
 #include "wtf/Vector.h"
 
 namespace WebCore {
 
 class CSSAnimationUpdate;
 class CSSFontSelector;
 class CSSRuleList;
 class CSSSelector;
 class CSSStyleSheet;
@@ skipping 156 matching lines @@
     // their dependency on Document* instead of grabbing one through StyleResolver.
     Document& document() { return m_document; }
 
     // FIXME: It could be better to call m_ruleSets.appendAuthorStyleSheets() directly after we factor StyleRsolver further.
     // https://bugs.webkit.org/show_bug.cgi?id=108890
     void appendAuthorStyleSheets(unsigned firstNew, const Vector<RefPtr<CSSStyleSheet> >&);
     void resetAuthorStyle(const ContainerNode*);
     void resetAtHostRules(const ShadowRoot*);
     void finishAppendAuthorStyleSheets();
 
+    void lazyAppendAuthorStyleSheets(unsigned firstNew, const Vector<RefPtr<CSSStyleSheet> >&);
+    void removePendingAuthorStyleSheets(const Vector<RefPtr<CSSStyleSheet> >&);
+    void appendPendingAuthorStyleSheets();
+    bool hasPendingAuthorStyleSheets() const { return m_pendingStyleSheets.size() > 0 || m_needCollectFeatures; }
+
     DocumentRuleSets& ruleSets() { return m_ruleSets; }
     const DocumentRuleSets& ruleSets() const { return m_ruleSets; }
     SelectorFilter& selectorFilter() { return m_selectorFilter; }
 
     void setBuildScopedStyleTreeInDocumentOrder(bool enabled) { m_styleTree.setBuildInDocumentOrder(enabled); }
     bool buildScopedStyleTreeInDocumentOrder() const { return m_styleTree.buildInDocumentOrder(); }
 
     ScopedStyleResolver* ensureScopedStyleResolver(const ContainerNode* scope)
     {
         return m_styleTree.ensureScopedStyleResolver(scope ? *scope : document());
@@ skipping 28 matching lines @@
 
     // FIXME: Rename to reflect the purpose, like didChangeFontSize or something.
     void invalidateMatchedPropertiesCache();
 
     // Exposed for RenderStyle::isStyleAvilable().
     static RenderStyle* styleNotYetAvailable() { return s_styleNotYetAvailable; }
 
     // FIXME: StyleResolver should not have this member or method.
     InspectorCSSOMWrappers& inspectorCSSOMWrappers() { return m_inspectorCSSOMWrappers; }
 
     const RuleFeatureSet& ruleFeatureSet() const { return m_features; }

[eseidel, 2013/11/06 01:39:10]

I'm confused.  This can now be stale right?  Don't all callers need to call
ensureRuleFeatureSet?

[tasak, 2013/11/06 05:42:26]

I left the method for fast-path, e.g. Document::createStyleResolver or
something.
However, I agree that it is very difficult to find which method we should use.
So I removed "ruleFeatureSet" and replaced "ruleFeatureSet" with
"ensureRuleFeatureSet"  (or just m_features in StyleResolver.cpp).

+    const RuleFeatureSet& ensureRuleFeatureSet()
+    {
+        if (hasPendingAuthorStyleSheets())
+            appendPendingAuthorStyleSheets(); // slow path.
+        return m_features;
+    }
 
     StyleSharingList& styleSharingList() { return m_styleSharingList; }
 
     bool hasRulesForId(const AtomicString&) const;
 
     void addToStyleSharingList(Element*);
     void clearStyleSharingList();
 
 #ifdef STYLE_STATS
     ALWAYS_INLINE static StyleSharingStats& styleSharingStats() { return m_styleSharingStats; }
 #endif
 
 private:
     // FontSelectorClient implementation.
     virtual void fontsNeedUpdate(FontSelector*);
 
 private:
     // FIXME: This should probably go away, folded into FontBuilder.
     void updateFont(StyleResolverState&);
 
+    void filterFontFaceAndViewportRules(const Vector<RefPtr<StyleRuleBase> >& rules, bool& needsResolveViewport);
+    void filterFontFaceAndViewportRulesFromSheet(StyleSheetContents*, bool& needsResolveViewport);
+    bool filterFontFaceAndViewportRulesFromAuthorStyleSheets(unsigned firstNew, const Vector<RefPtr<CSSStyleSheet> >& styleSheets);
+
     void collectPseudoRulesForElement(Element*, ElementRuleCollector&, PseudoId, unsigned rulesToInclude);
     void matchUARules(ElementRuleCollector&, RuleSet*);
     void matchAuthorRules(Element*, ElementRuleCollector&, bool includeEmptyRules);
     void matchAuthorRulesForShadowHost(Element*, ElementRuleCollector&, bool includeEmptyRules, Vector<ScopedStyleResolver*, 8>& resolvers, Vector<ScopedStyleResolver*, 8>& resolversInShadowTree);
     void matchHostRules(Element*, ScopedStyleResolver*, ElementRuleCollector&, bool includeEmptyRules);
     void matchAllRules(StyleResolverState&, ElementRuleCollector&, bool matchAuthorAndUserStyles, bool includeSMILProperties);
     void matchUARules(ElementRuleCollector&);
     void matchUserRules(ElementRuleCollector&, bool includeEmptyRules);
     void collectFeatures();
     void collectTreeBoundaryCrossingRules(ElementRuleCollector&, bool includeEmptyRules);
+    void resetRuleFeatures();
 
     bool fastRejectSelector(const RuleData&) const;
 
     void applyMatchedProperties(StyleResolverState&, const MatchResult&);
 
     enum StyleApplicationPass {
         VariableDefinitions,
         AnimationProperties,
         HighPriorityProperties,
         LowPriorityProperties
@@ skipping 35 matching lines @@
 
     Document& m_document;
     SelectorFilter m_selectorFilter;
 
     bool m_matchAuthorAndUserStyles;
 
     RefPtr<CSSFontSelector> m_fontSelector;
 
     RefPtr<ViewportStyleResolver> m_viewportStyleResolver;
 
+    ListHashSet<CSSStyleSheet*, 16> m_pendingStyleSheets;
+
     ScopedStyleTree m_styleTree;
 
     // FIXME: The entire logic of collecting features on StyleResolver, as well astransferring them
     // between various parts of machinery smells wrong. This needs to be better somehow.
     RuleFeatureSet m_features;
     OwnPtr<RuleSet> m_siblingRuleSet;
     OwnPtr<RuleSet> m_uncommonAttributeRuleSet;
+    bool m_needCollectFeatures;
 
     InspectorCSSOMWrappers m_inspectorCSSOMWrappers;
 
     StyleResourceLoader m_styleResourceLoader;
 
     StyleSharingList m_styleSharingList;
 
 #ifdef STYLE_STATS
     static StyleSharingStats m_styleSharingStats;
 #endif
 };
 
 inline bool checkRegionSelector(const CSSSelector* regionSelector, Element* regionElement)
 {
     if (!regionSelector || !regionElement)
         return false;
 
     SelectorChecker selectorChecker(regionElement->document(), SelectorChecker::QueryingRules);
     for (const CSSSelector* s = regionSelector; s; s = CSSSelectorList::next(s)) {
         SelectorChecker::SelectorCheckingContext selectorCheckingContext(s, regionElement, SelectorChecker::VisitedMatchDisabled);
         PseudoId ignoreDynamicPseudo = NOPSEUDO;
         if (selectorChecker.match(selectorCheckingContext, ignoreDynamicPseudo, DOMSiblingTraversalStrategy()) == SelectorChecker::SelectorMatches)
             return true;
     }
     return false;
 }
 
+inline bool isDocumentScope(const ContainerNode* scope)
+{
+    return !scope || scope->isDocumentNode();
+}
+
+inline void appendPendingStyleSheetsIfNeeded(StyleResolver* styleResolver)
+{
+    if (!styleResolver || !styleResolver->hasPendingAuthorStyleSheets())
+        return;
+    styleResolver->appendPendingAuthorStyleSheets();
+}
+
 } // namespace WebCore
 
 #endif // StyleResolver_h