RuleSet should use malloc rather than Vector

Source/core/css/RuleSet.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,
  * 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.
  *
  */
 
 #ifndef RuleSet_h
 #define RuleSet_h
 
 #include "core/css/RuleFeature.h"
 #include "core/css/StyleRule.h"
 #include "wtf/Forward.h"
 #include "wtf/HashMap.h"
 #include "wtf/LinkedStack.h"
+#include "wtf/OwnArrayPtr.h"
 
 namespace WebCore {
 
 enum AddRuleFlags {
     RuleHasNoSpecialState         = 0,
     RuleHasDocumentSecurityOrigin = 1,
     RuleCanUseFastCheckSelector   = 1 << 1,
     RuleIsInRegionRule            = 1 << 2,
 };
     
 enum PropertyWhitelistType {
     PropertyWhitelistNone   = 0,
     PropertyWhitelistRegion,
     PropertyWhitelistCue
 };
 
 class CSSSelector;
 class ContainerNode;
 class MediaQueryEvaluator;
 class StyleResolver;
 class StyleRuleRegion;
 class StyleSheetContents;
 
 class RuleData {
+    NEW_DELETE_SAME_AS_MALLOC_FREE;
 public:
     RuleData(StyleRule*, unsigned selectorIndex, unsigned position, AddRuleFlags);
 
     unsigned position() const { return m_position; }
     StyleRule* rule() const { return m_rule; }
     const CSSSelector* selector() const { return m_rule->selectorList().selectorAt(m_selectorIndex); }
     unsigned selectorIndex() const { return m_selectorIndex; }
 
+    bool isLastInArray() const { return m_isLastInArray; }
+    void setLastInArray(bool flag) { m_isLastInArray = flag ? 1 : 0; }

[esprehn, 2013/06/26 00:37:33]

I don't think you need the ternary in here.

[abarth-chromium, 2013/06/26 00:57:00]

Done.

+
     bool hasFastCheckableSelector() const { return m_hasFastCheckableSelector; }
     bool hasMultipartSelector() const { return m_hasMultipartSelector; }
     bool hasRightmostSelectorMatchingHTMLBasedOnRuleHash() const { return m_hasRightmostSelectorMatchingHTMLBasedOnRuleHash; }
     bool containsUncommonAttributeSelector() const { return m_containsUncommonAttributeSelector; }
     unsigned specificity() const { return m_specificity; }
     unsigned linkMatchType() const { return m_linkMatchType; }
     bool hasDocumentSecurityOrigin() const { return m_hasDocumentSecurityOrigin; }
     PropertyWhitelistType propertyWhitelistType(bool isMatchingUARules = false) const { return isMatchingUARules ? PropertyWhitelistNone : static_cast<PropertyWhitelistType>(m_propertyWhitelistType); }
     // Try to balance between memory usage (there can be lots of RuleData objects) and good filtering performance.
     static const unsigned maximumIdentifierCount = 4;
     const unsigned* descendantSelectorIdentifierHashes() const { return m_descendantSelectorIdentifierHashes; }
 
     void reportMemoryUsage(MemoryObjectInfo*) const;
 
 private:
     StyleRule* m_rule;
-    unsigned m_selectorIndex : 13;
+    unsigned m_selectorIndex : 12;
+    unsigned m_isLastInArray : 1; // We store an array of RuleData objects in a primitive array.
     // This number was picked fairly arbitrarily. We can probably lower it if we need to.
     // Some simple testing showed <100,000 RuleData's on large sites.
     unsigned m_position : 18;
     unsigned m_hasFastCheckableSelector : 1;
     unsigned m_specificity : 24;
     unsigned m_hasMultipartSelector : 1;
     unsigned m_hasRightmostSelectorMatchingHTMLBasedOnRuleHash : 1;
     unsigned m_containsUncommonAttributeSelector : 1;
     unsigned m_linkMatchType : 2; //  SelectorChecker::LinkMatchMask
     unsigned m_hasDocumentSecurityOrigin : 1;
@@ skipping 15 matching lines @@
     WTF_MAKE_NONCOPYABLE(RuleSet); WTF_MAKE_FAST_ALLOCATED;
 public:
     static PassOwnPtr<RuleSet> create() { return adoptPtr(new RuleSet); }
 
     void addRulesFromSheet(StyleSheetContents*, const MediaQueryEvaluator&, StyleResolver* = 0, const ContainerNode* = 0);
     void addStyleRule(StyleRule*, AddRuleFlags);
     void addRule(StyleRule*, unsigned selectorIndex, AddRuleFlags);
 
     const RuleFeatureSet& features() const { return m_features; }
 
-    const Vector<RuleData>* idRules(AtomicStringImpl* key) const { ASSERT(!m_pendingRules); return m_idRules.get(key); }
-    const Vector<RuleData>* classRules(AtomicStringImpl* key) const { ASSERT(!m_pendingRules); return m_classRules.get(key); }
-    const Vector<RuleData>* tagRules(AtomicStringImpl* key) const { ASSERT(!m_pendingRules); return m_tagRules.get(key); }
-    const Vector<RuleData>* shadowPseudoElementRules(AtomicStringImpl* key) const { ASSERT(!m_pendingRules); return m_shadowPseudoElementRules.get(key); }
+    const RuleData* idRules(AtomicStringImpl* key) const { ASSERT(!m_pendingRules); return m_idRules.get(key); }
+    const RuleData* classRules(AtomicStringImpl* key) const { ASSERT(!m_pendingRules); return m_classRules.get(key); }
+    const RuleData* tagRules(AtomicStringImpl* key) const { ASSERT(!m_pendingRules); return m_tagRules.get(key); }
+    const RuleData* shadowPseudoElementRules(AtomicStringImpl* key) const { ASSERT(!m_pendingRules); return m_shadowPseudoElementRules.get(key); }

[esprehn, 2013/06/26 00:37:33]

We might consider a WTF class someday that does the isLastElement() check
internal to the MarkedArray<RuleData>::iterator.

[abarth-chromium, 2013/06/26 00:57:00]

Yeah.

     const Vector<RuleData>* linkPseudoClassRules() const { ASSERT(!m_pendingRules); return &m_linkPseudoClassRules; }
     const Vector<RuleData>* cuePseudoRules() const { ASSERT(!m_pendingRules); return &m_cuePseudoRules; }
     const Vector<RuleData>* focusPseudoClassRules() const { ASSERT(!m_pendingRules); return &m_focusPseudoClassRules; }
     const Vector<RuleData>* universalRules() const { ASSERT(!m_pendingRules); return &m_universalRules; }
     const Vector<StyleRulePage*>& pageRules() const { ASSERT(!m_pendingRules); return m_pageRules; }
 
     unsigned ruleCount() const { return m_ruleCount; }
 
     void compactRulesIfNeeded()
     {
@@ skipping 10 matching lines @@
         void reportMemoryUsage(MemoryObjectInfo*) const;
 
         const CSSSelector* selector;
         OwnPtr<RuleSet> ruleSet;
     };
 
     Vector<RuleSetSelectorPair> m_regionSelectorsAndRuleSets;
 
 private:
     typedef HashMap<AtomicStringImpl*, OwnPtr<LinkedStack<RuleData> > > PendingRuleMap;
-    typedef HashMap<AtomicStringImpl*, OwnPtr<Vector<RuleData> > > CompactRuleMap;
+    typedef HashMap<AtomicStringImpl*, OwnPtr<RuleData> > CompactRuleMap;
 
     RuleSet()
         : m_ruleCount(0)
     {
     }
 
     void addToRuleSet(AtomicStringImpl* key, PendingRuleMap&, const RuleData&);
     void addPageRule(StyleRulePage*);
     void addRegionRule(StyleRuleRegion*, bool hasDocumentSecurityOrigin);
 
@@ skipping 28 matching lines @@
     RuleFeatureSet m_features;
     Vector<StyleRulePage*> m_pageRules;
 
     unsigned m_ruleCount;
     OwnPtr<PendingRuleMaps> m_pendingRules;
 };
 
 } // namespace WebCore
 
 #endif // RuleSet_h