Use invalidation sets for nth invalidations.

third_party/WebKit/Source/core/css/RuleFeature.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 84 matching lines @@
     // Collect descendant and sibling invalidation sets.
     void collectInvalidationSetsForClass(InvalidationLists&, Element&, const AtomicString& className) const;
     void collectInvalidationSetsForId(InvalidationLists&, Element&, const AtomicString& id) const;
     void collectInvalidationSetsForAttribute(InvalidationLists&, Element&, const QualifiedName& attributeName) const;
     void collectInvalidationSetsForPseudoClass(InvalidationLists&, Element&, CSSSelector::PseudoType) const;
 
     void collectSiblingInvalidationSetForClass(InvalidationLists&, Element&, const AtomicString& className, unsigned minDirectAdjacent) const;
     void collectSiblingInvalidationSetForId(InvalidationLists&, Element&, const AtomicString& id, unsigned minDirectAdjacent) const;
     void collectSiblingInvalidationSetForAttribute(InvalidationLists&, Element&, const QualifiedName& attributeName, unsigned minDirectAdjacent) const;
     void collectUniversalSiblingInvalidationSet(InvalidationLists&, unsigned minDirectAdjacent) const;
+    void collectNthInvalidationSet(InvalidationLists&) const;
 
     bool hasIdsInSelectors() const
     {
         return m_idInvalidationSets.size() > 0;
     }
 
     DECLARE_TRACE();
 
     HeapVector<RuleFeature> siblingRules;
     HeapVector<RuleFeature> uncommonAttributeRules;
@@ skipping 19 matching lines @@
         unsigned maxDirectAdjacentSelectors = 0;
     };
 
     SelectorPreMatch collectFeaturesFromSelector(const CSSSelector&, FeatureMetadata&);
 
     InvalidationSet& ensureClassInvalidationSet(const AtomicString& className, InvalidationType);
     InvalidationSet& ensureAttributeInvalidationSet(const AtomicString& attributeName, InvalidationType);
     InvalidationSet& ensureIdInvalidationSet(const AtomicString& id, InvalidationType);
     InvalidationSet& ensurePseudoInvalidationSet(CSSSelector::PseudoType, InvalidationType);
     SiblingInvalidationSet& ensureUniversalSiblingInvalidationSet();
+    DescendantInvalidationSet& ensureNthInvalidationSet();
 
     void updateInvalidationSets(const RuleData&);
     void updateInvalidationSetsForContentAttribute(const RuleData&);
 
     struct InvalidationSetFeatures {
         DISALLOW_NEW();
 
         Vector<AtomicString> classes;
         Vector<AtomicString> attributes;
         AtomicString id;
         AtomicString tagName;
         unsigned maxDirectAdjacentSelectors = UINT_MAX;
         bool customPseudoElement = false;
         bool hasBeforeOrAfter = false;
         bool treeBoundaryCrossing = false;
         bool adjacent = false;
         bool insertionPointCrossing = false;
         bool forceSubtree = false;
         bool contentPseudoCrossing = false;
         bool invalidatesSlotted = false;
+        bool hasNthPseudo = false;
     };
 
     static bool extractInvalidationSetFeature(const CSSSelector&, InvalidationSetFeatures&);
 
     enum UseFeaturesType { UseFeatures, ForceSubtree };
 
     enum PositionType { Subject, Ancestor };
     std::pair<const CSSSelector*, UseFeaturesType> extractInvalidationSetFeatures(const CSSSelector&, InvalidationSetFeatures&, PositionType, CSSSelector::PseudoType = CSSSelector::PseudoUnknown);
 
     void addFeaturesToInvalidationSet(InvalidationSet&, const InvalidationSetFeatures&);
     void addFeaturesToInvalidationSets(const CSSSelector*, InvalidationSetFeatures* siblingFeatures, InvalidationSetFeatures& descendantFeatures);
     void addFeaturesToUniversalSiblingInvalidationSet(const InvalidationSetFeatures& siblingFeatures, const InvalidationSetFeatures& descendantFeatures);
 
     void addClassToInvalidationSet(const AtomicString& className, Element&);
 
     FeatureMetadata m_metadata;
     InvalidationSetMap m_classInvalidationSets;
     InvalidationSetMap m_attributeInvalidationSets;
     InvalidationSetMap m_idInvalidationSets;
     PseudoTypeInvalidationSetMap m_pseudoInvalidationSets;
     RefPtr<SiblingInvalidationSet> m_universalSiblingInvalidationSet;
+    RefPtr<DescendantInvalidationSet> m_nthInvalidationSet;
 
     friend class RuleFeatureSetTest;
 };
 
 } // namespace blink
 
 #endif // RuleFeature_h