Use LocalStyleChange for classes in rightmost compound selector.

Source/core/css/RuleFeature.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 2004-2005 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2006, 2007 Nicholas Shanks (webkit@nickshanks.com)
  * Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2007 Alexey Proskuryakov <ap@webkit.org>
  * Copyright (C) 2007, 2008 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (c) 2011, Code Aurora Forum. All rights reserved.
  * Copyright (C) Research In Motion Limited 2011. All rights reserved.
@@ skipping 82 matching lines @@
     case CSSSelector::PseudoUnresolved:
         return true;
     default:
         return false;
     }
     ASSERT_NOT_REACHED();
     return false;
 }
 
 // This method is somewhat conservative in what it accepts.
-static bool supportsClassDescendantInvalidation(const CSSSelector& selector)
+RuleFeatureSet::InvalidationMode RuleFeatureSet::supportsClassDescendantInvalidation(const CSSSelector& selector)
 {
     bool foundDescendantRelation = false;
     bool foundIdent = false;
     for (const CSSSelector* component = &selector; component; component = component->tagHistory()) {
 
         // FIXME: We should allow pseudo elements, but we need to change how they hook
         // into recalcStyle by moving them to recalcOwnStyle instead of recalcChildStyle.
 
         // FIXME: next up: Tag and Id.
         if (component->m_match == CSSSelector::Class) {
             if (!foundDescendantRelation)
                 foundIdent = true;
         } else if (!isSkippableComponentForInvalidation(*component)) {
-            return false;
+            return foundDescendantRelation ? UseLocalStyleChange : UseSubtreeStyleChange;
         }
         // FIXME: We can probably support ShadowAll and ShadowDeep.
         switch (component->relation()) {
         case CSSSelector::Descendant:
         case CSSSelector::Child:
             foundDescendantRelation = true;
             // Fall through!
         case CSSSelector::SubSelector:
             continue;
         default:
-            return false;
+            return UseLocalStyleChange;
         }
     }
-    return foundIdent;
+    return foundIdent ? UseInvalidationSets : UseLocalStyleChange;
 }
 
 void extractClassIdOrTag(const CSSSelector& selector, Vector<AtomicString>& classes, AtomicString& id, AtomicString& tagName)
 {
     if (selector.m_match == CSSSelector::Tag)
         tagName = selector.tagQName().localName();
     else if (selector.m_match == CSSSelector::Id)
         id = selector.value();
     else if (selector.m_match == CSSSelector::Class)
         classes.append(selector.value());
 }
 
 RuleFeatureSet::RuleFeatureSet()
     : m_targetedStyleRecalcEnabled(RuntimeEnabledFeatures::targetedStyleRecalcEnabled())
 {
 }
 
-bool RuleFeatureSet::updateClassInvalidationSets(const CSSSelector& selector)
+RuleFeatureSet::InvalidationMode RuleFeatureSet::updateClassInvalidationSets(const CSSSelector& selector)
 {
-    if (!supportsClassDescendantInvalidation(selector))
-        return false;
+    InvalidationMode mode = supportsClassDescendantInvalidation(selector);
+    if (mode != UseInvalidationSets)
+        return mode;
 
     Vector<AtomicString> classes;
     AtomicString id;
     AtomicString tagName;
 
     const CSSSelector* lastSelector = &selector;
     for (; lastSelector; lastSelector = lastSelector->tagHistory()) {
         extractClassIdOrTag(*lastSelector, classes, id, tagName);
         if (lastSelector->m_match == CSSSelector::Class)
             ensureClassInvalidationSet(lastSelector->value());
         if (lastSelector->relation() != CSSSelector::SubSelector)
             break;
     }
 
     if (!lastSelector)
-        return true;
+        return UseInvalidationSets;
 
     for (const CSSSelector* current = lastSelector->tagHistory(); current; current = current->tagHistory()) {
         if (current->m_match == CSSSelector::Class) {
             DescendantInvalidationSet& invalidationSet = ensureClassInvalidationSet(current->value());
             if (!id.isEmpty())
                 invalidationSet.addId(id);
             if (!tagName.isEmpty())
                 invalidationSet.addTagName(tagName);
             for (Vector<AtomicString>::const_iterator it = classes.begin(); it != classes.end(); ++it) {
                 invalidationSet.addClass(*it);
             }
         }
     }
-    return true;
+    return UseInvalidationSets;
 }
 
 void RuleFeatureSet::addAttributeInASelector(const AtomicString& attributeName)
 {
     m_metadata.attrsInRules.add(attributeName);
 }
 
 void RuleFeatureSet::collectFeaturesFromRuleData(const RuleData& ruleData)
 {
     FeatureMetadata metadata;
-    bool selectorUsesClassInvalidationSet = false;
+    InvalidationMode mode = UseSubtreeStyleChange;
     if (m_targetedStyleRecalcEnabled)
-        selectorUsesClassInvalidationSet = updateClassInvalidationSets(ruleData.selector());
+        mode = updateClassInvalidationSets(ruleData.selector());
 
-    SelectorFeatureCollectionMode collectionMode;
-    if (selectorUsesClassInvalidationSet)
-        collectionMode = DontProcessClasses;
-    else
-        collectionMode = ProcessClasses;
-    collectFeaturesFromSelector(ruleData.selector(), metadata, collectionMode);
+    collectFeaturesFromSelector(ruleData.selector(), metadata, mode);
     m_metadata.add(metadata);
 
     if (metadata.foundSiblingSelector)
         siblingRules.append(RuleFeature(ruleData.rule(), ruleData.selectorIndex(), ruleData.hasDocumentSecurityOrigin()));
     if (ruleData.containsUncommonAttributeSelector())
         uncommonAttributeRules.append(RuleFeature(ruleData.rule(), ruleData.selectorIndex(), ruleData.hasDocumentSecurityOrigin()));
 }
 
 DescendantInvalidationSet& RuleFeatureSet::ensureClassInvalidationSet(const AtomicString& className)
 {
     InvalidationSetMap::AddResult addResult = m_classInvalidationSets.add(className, nullptr);
     if (addResult.isNewEntry)
         addResult.storedValue->value = DescendantInvalidationSet::create();
     return *addResult.storedValue->value;
 }
 
 void RuleFeatureSet::collectFeaturesFromSelector(const CSSSelector& selector)
 {
-    collectFeaturesFromSelector(selector, m_metadata, ProcessClasses);
+    collectFeaturesFromSelector(selector, m_metadata, UseSubtreeStyleChange);
 }
 
-void RuleFeatureSet::collectFeaturesFromSelector(const CSSSelector& selector, RuleFeatureSet::FeatureMetadata& metadata, SelectorFeatureCollectionMode collectionMode)
+void RuleFeatureSet::collectFeaturesFromSelector(const CSSSelector& selector, RuleFeatureSet::FeatureMetadata& metadata, InvalidationMode mode)
 {
     unsigned maxDirectAdjacentSelectors = 0;
 
     for (const CSSSelector* current = &selector; current; current = current->tagHistory()) {
         if (current->m_match == CSSSelector::Id) {
             metadata.idsInRules.add(current->value());
-        } else if (current->m_match == CSSSelector::Class && collectionMode == ProcessClasses) {
+        } else if (current->m_match == CSSSelector::Class && mode != UseInvalidationSets) {

[esprehn, 2014/03/13 23:28:13]

This is confusing since you're saying "mode is not UseInvalidationSets" and then
you're creating an invalidation set right below.

[rune, 2014/03/14 13:01:19]

Renamed now.

             DescendantInvalidationSet& invalidationSet = ensureClassInvalidationSet(current->value());
-            invalidationSet.setWholeSubtreeInvalid();
+            if (mode == UseSubtreeStyleChange)
+                invalidationSet.setWholeSubtreeInvalid();
         } else if (current->isAttributeSelector()) {
             metadata.attrsInRules.add(current->attribute().localName());
         }
         if (current->pseudoType() == CSSSelector::PseudoFirstLine)
             metadata.usesFirstLineRules = true;
         if (current->isDirectAdjacentSelector()) {
             maxDirectAdjacentSelectors++;
         } else if (maxDirectAdjacentSelectors) {
             if (maxDirectAdjacentSelectors > metadata.maxDirectAdjacentSelectors)
                 metadata.maxDirectAdjacentSelectors = maxDirectAdjacentSelectors;
             maxDirectAdjacentSelectors = 0;
         }
         if (current->isSiblingSelector())
             metadata.foundSiblingSelector = true;
 
-        collectFeaturesFromSelectorList(current->selectorList(), metadata, collectionMode);
+        collectFeaturesFromSelectorList(current->selectorList(), metadata, mode);
+
+        if (mode == UseLocalStyleChange && current->relation() != CSSSelector::SubSelector)
+            mode = UseSubtreeStyleChange;
     }
 
     ASSERT(!maxDirectAdjacentSelectors);
 }
 
-void RuleFeatureSet::collectFeaturesFromSelectorList(const CSSSelectorList* selectorList, RuleFeatureSet::FeatureMetadata& metadata, SelectorFeatureCollectionMode collectionMode)
+void RuleFeatureSet::collectFeaturesFromSelectorList(const CSSSelectorList* selectorList, RuleFeatureSet::FeatureMetadata& metadata, InvalidationMode mode)
 {
     if (!selectorList)
         return;
 
     for (const CSSSelector* selector = selectorList->first(); selector; selector = CSSSelectorList::next(*selector))
-        collectFeaturesFromSelector(*selector, metadata, collectionMode);
+        collectFeaturesFromSelector(*selector, metadata, mode);
 }
 
 void RuleFeatureSet::FeatureMetadata::add(const FeatureMetadata& other)
 {
     usesFirstLineRules = usesFirstLineRules || other.usesFirstLineRules;
     maxDirectAdjacentSelectors = std::max(maxDirectAdjacentSelectors, other.maxDirectAdjacentSelectors);
 
     HashSet<AtomicString>::const_iterator end = other.idsInRules.end();
     for (HashSet<AtomicString>::const_iterator it = other.idsInRules.begin(); it != end; ++it)
         idsInRules.add(*it);
@@ skipping 172 matching lines @@
     }
 
     invalidationClasses.remove(oldSize, invalidationClasses.size() - oldSize);
     element->clearChildNeedsStyleInvalidation();
     element->clearNeedsStyleInvalidation();
 
     return thisElementNeedsStyleRecalc;
 }
 
 } // namespace WebCore