Make right-most compound check explicit.

Source/core/css/SelectorChecker.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, 2013 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 244 matching lines @@
         if (context.selector->isCustomPseudoElement()) {
             if (!matchesCustomPseudoElement(context.element, *context.selector))
                 return SelectorFailsLocally;
         } else if (context.selector->isContentPseudoElement()) {
             if (!context.element->isInShadowTree() || !context.element->isInsertionPoint())
                 return SelectorFailsLocally;
         } else if (context.selector->isShadowPseudoElement()) {
             if (!context.element->isInShadowTree() || !context.previousElement)
                 return SelectorFailsCompletely;
         } else {
-            if ((!context.elementStyle && m_mode == ResolvingStyle) || m_mode == QueryingRules)
+            if ((!context.inRightmostCompound && m_mode == ResolvingStyle) || m_mode == QueryingRules)
                 return SelectorFailsLocally;
 
             PseudoId pseudoId = CSSSelector::pseudoId(context.selector->pseudoType());
             if (pseudoId != NOPSEUDO && m_mode != SharingRules)
                 result.dynamicPseudo = pseudoId;
         }
     }
 
     // Prepare next selector
     if (context.selector->isLastInTagHistory()) {
@@ skipping 40 matching lines @@
 SelectorChecker::Match SelectorChecker::matchForSubSelector(const SelectorCheckingContext& context, MatchResult& result) const
 {
     SelectorCheckingContext nextContext = prepareNextContextForRelation(context);
 
     PseudoId dynamicPseudo = result.dynamicPseudo;
     // a selector is invalid if something follows a pseudo-element
     // We make an exception for scrollbar pseudo elements and allow a set of pseudo classes (but nothing else)
     // to follow the pseudo elements.
     nextContext.hasScrollbarPseudo = dynamicPseudo != NOPSEUDO && (context.scrollbar || dynamicPseudo == SCROLLBAR_CORNER || dynamicPseudo == RESIZER);
     nextContext.hasSelectionPseudo = dynamicPseudo == SELECTION;
-    if ((context.elementStyle || m_mode == CollectingCSSRules || m_mode == CollectingStyleRules || m_mode == QueryingRules) && dynamicPseudo != NOPSEUDO
+    if ((context.inRightmostCompound || m_mode == CollectingCSSRules || m_mode == CollectingStyleRules || m_mode == QueryingRules) && dynamicPseudo != NOPSEUDO
         && !nextContext.hasSelectionPseudo
         && !(nextContext.hasScrollbarPseudo && nextContext.selector->match() == CSSSelector::PseudoClass))
         return SelectorFailsCompletely;
 
     nextContext.isSubSelector = true;
     return matchSelector(nextContext, result);
 }
 
 static inline Element* parentOrShadowHostButDisallowEscapingUserAgentShadowTree(const Element& element)
 {
@@ skipping 30 matching lines @@
     switch (relation) {
     case CSSSelector::Descendant:
         if (context.selector->relationIsAffectedByPseudoContent()) {
             for (Element* element = context.element; element; element = element->parentElement()) {
                 if (matchForShadowDistributed(nextContext, *element, result) == SelectorMatches)
                     return SelectorMatches;
             }
             return SelectorFailsCompletely;
         }
         nextContext.isSubSelector = false;
-        nextContext.elementStyle = 0;
+        nextContext.inRightmostCompound = false;
 
         if (nextContext.selector->isShadowPseudoElement())
             return matchForPseudoShadow(nextContext, context.element->containingShadowRoot(), result);
 
         for (nextContext.element = parentElement(context); nextContext.element; nextContext.element = parentElement(nextContext)) {
             Match match = matchSelector(nextContext, result);
             if (match == SelectorMatches || match == SelectorFailsCompletely)
                 return match;
             if (nextSelectorExceedsScope(nextContext))
                 return SelectorFailsCompletely;
         }
         return SelectorFailsCompletely;
     case CSSSelector::Child:
         {
             if (context.selector->relationIsAffectedByPseudoContent())
                 return matchForShadowDistributed(nextContext, *context.element, result);
 
             nextContext.isSubSelector = false;
-            nextContext.elementStyle = 0;
+            nextContext.inRightmostCompound = false;
 
             if (nextContext.selector->isShadowPseudoElement())
                 return matchForPseudoShadow(nextContext, context.element->parentNode(), result);
 
             nextContext.element = parentElement(context);
             if (!nextContext.element)
                 return SelectorFailsCompletely;
             return matchSelector(nextContext, result);
         }
     case CSSSelector::DirectAdjacent:
         // Shadow roots can't have sibling elements
         if (nextContext.selector->isShadowPseudoElement())
             return SelectorFailsCompletely;
 
         if (m_mode == ResolvingStyle) {
             if (ContainerNode* parent = context.element->parentElementOrShadowRoot())
                 parent->setChildrenAffectedByDirectAdjacentRules();
         }
         nextContext.element = ElementTraversal::previousSibling(*context.element);
         if (!nextContext.element)
             return SelectorFailsAllSiblings;
         nextContext.isSubSelector = false;
-        nextContext.elementStyle = 0;
+        nextContext.inRightmostCompound = false;
         return matchSelector(nextContext, result);
 
     case CSSSelector::IndirectAdjacent:
         // Shadow roots can't have sibling elements
         if (nextContext.selector->isShadowPseudoElement())
             return SelectorFailsCompletely;
 
         if (m_mode == ResolvingStyle) {
             if (ContainerNode* parent = context.element->parentElementOrShadowRoot())
                 parent->setChildrenAffectedByIndirectAdjacentRules();
         }
         nextContext.element = ElementTraversal::previousSibling(*context.element);
         nextContext.isSubSelector = false;
-        nextContext.elementStyle = 0;
+        nextContext.inRightmostCompound = false;
         for (; nextContext.element; nextContext.element = ElementTraversal::previousSibling(*nextContext.element)) {
             Match match = matchSelector(nextContext, result);
             if (match == SelectorMatches || match == SelectorFailsAllSiblings || match == SelectorFailsCompletely)
                 return match;
         };
         return SelectorFailsAllSiblings;
 
     case CSSSelector::ShadowPseudo:
         {
             // If we're in the same tree-scope as the scoping element, then following a shadow descendant combinator would escape that and thus the scope.
             if (context.scope && context.scope->shadowHost() && context.scope->shadowHost()->treeScope() == context.element->treeScope())
                 return SelectorFailsCompletely;
 
             Element* shadowHost = context.element->shadowHost();
             if (!shadowHost)
                 return SelectorFailsCompletely;
             nextContext.element = shadowHost;
             nextContext.isSubSelector = false;
-            nextContext.elementStyle = 0;
+            nextContext.inRightmostCompound = false;
             return matchSelector(nextContext, result);
         }
 
     case CSSSelector::ShadowDeep:
         {
             if (context.selector->relationIsAffectedByPseudoContent()) {
                 for (Element* element = context.element; element; element = parentOrShadowHostButDisallowEscapingUserAgentShadowTree(*element)) {
                     if (matchForShadowDistributed(nextContext, *element, result) == SelectorMatches)
                         return SelectorMatches;
                 }
                 return SelectorFailsCompletely;
             }
 
             nextContext.isSubSelector = false;
-            nextContext.elementStyle = 0;
+            nextContext.inRightmostCompound = false;
             for (nextContext.element = parentOrShadowHostButDisallowEscapingUserAgentShadowTree(*context.element); nextContext.element; nextContext.element = parentOrShadowHostButDisallowEscapingUserAgentShadowTree(*nextContext.element)) {
                 Match match = matchSelector(nextContext, result);
                 if (match == SelectorMatches || match == SelectorFailsCompletely)
                     return match;
                 if (nextSelectorExceedsScope(nextContext))
                     return SelectorFailsCompletely;
             }
             return SelectorFailsCompletely;
         }
 
     case CSSSelector::SubSelector:
         ASSERT_NOT_REACHED();
     }
 
     ASSERT_NOT_REACHED();
     return SelectorFailsCompletely;
 }
 
 SelectorChecker::Match SelectorChecker::matchForShadowDistributed(const SelectorCheckingContext& context, const Element& element, MatchResult& result) const
 {
     WillBeHeapVector<RawPtrWillBeMember<InsertionPoint>, 8> insertionPoints;
     collectDestinationInsertionPoints(element, insertionPoints);
     SelectorCheckingContext nextContext(context);
     nextContext.isSubSelector = false;
-    nextContext.elementStyle = 0;
+    nextContext.inRightmostCompound = false;
     for (const auto& insertionPoint : insertionPoints) {
         nextContext.element = insertionPoint;
         // TODO(esprehn): Why does SharingRules have a special case?
         if (m_mode == SharingRules)
             nextContext.scope = insertionPoint->containingShadowRoot();
         if (match(nextContext, result))
             return SelectorMatches;
     }
     return SelectorFailsLocally;
 }
@@ skipping 220 matching lines @@
                 if (n->isTextNode()) {
                     Text* textNode = toText(n);
                     if (!textNode->data().isEmpty()) {
                         result = false;
                         break;
                     }
                 }
             }
             if (m_mode == ResolvingStyle) {
                 element.setStyleAffectedByEmpty();
-                if (context.elementStyle)
+                if (context.inRightmostCompound)
                     context.elementStyle->setEmptyState(result);
                 else if (element.computedStyle() && (element.document().styleEngine().usesSiblingRules() || element.computedStyle()->unique()))
                     element.mutableComputedStyle()->setEmptyState(result);
             }
             return result;
         }
     case CSSSelector::PseudoFirstChild:
         if (ContainerNode* parent = element.parentElementOrDocumentFragment()) {
             if (m_mode == ResolvingStyle) {
                 parent->setChildrenAffectedByFirstChildRules();
@@ skipping 109 matching lines @@
         break;
     case CSSSelector::PseudoAutofill:
         return element.isFormControlElement() && toHTMLFormControlElement(element).isAutofilled();
     case CSSSelector::PseudoAnyLink:
     case CSSSelector::PseudoLink:
         return element.isLink();
     case CSSSelector::PseudoVisited:
         return element.isLink() && context.visitedMatchType == VisitedMatchEnabled;
     case CSSSelector::PseudoDrag:
         if (m_mode == ResolvingStyle) {
-            if (context.elementStyle)
+            if (context.inRightmostCompound)
                 context.elementStyle->setAffectedByDrag();
             else
                 element.setChildrenOrSiblingsAffectedByDrag();
         }
         return element.layoutObject() && element.layoutObject()->isDragging();
     case CSSSelector::PseudoFocus:
         if (m_mode == ResolvingStyle) {
-            if (context.elementStyle)
+            if (context.inRightmostCompound)
                 context.elementStyle->setAffectedByFocus();
             else
                 element.setChildrenOrSiblingsAffectedByFocus();
         }
         return matchesFocusPseudoClass(element);
     case CSSSelector::PseudoHover:
         if (m_mode == ResolvingStyle) {
-            if (context.elementStyle)
+            if (context.inRightmostCompound)
                 context.elementStyle->setAffectedByHover();
             else
                 element.setChildrenOrSiblingsAffectedByHover();
         }
         if (!shouldMatchHoverOrActive(context))
             return false;
         if (InspectorInstrumentation::forcePseudoState(&element, CSSSelector::PseudoHover))
             return true;
         return element.hovered();
     case CSSSelector::PseudoActive:
         if (m_mode == ResolvingStyle) {
-            if (context.elementStyle)
+            if (context.inRightmostCompound)
                 context.elementStyle->setAffectedByActive();
             else
                 element.setChildrenOrSiblingsAffectedByActive();
         }
         if (!shouldMatchHoverOrActive(context))
             return false;
         if (InspectorInstrumentation::forcePseudoState(&element, CSSSelector::PseudoActive))
             return true;
         return element.active();
     case CSSSelector::PseudoEnabled:
@@ skipping 190 matching lines @@
                 maxSpecificity = std::max(maxSpecificity, hostContext.selector->specificity() + subResult.specificity);
                 break;
             }
             hostContext.scopeContainsLastMatchedElement = false;
             hostContext.treatShadowHostAsNormalScope = false;
             hostContext.scope = nullptr;
 
             if (selector.pseudoType() == CSSSelector::PseudoHost)
                 break;
 
-            hostContext.elementStyle = 0;
+            hostContext.inRightmostCompound = false;
             nextElement = ComposedTreeTraversal::parentElement(*nextElement);
         } while (nextElement);
     }
     if (matched) {
         if (specificity)
             *specificity = maxSpecificity;
         return true;
     }
 
     // FIXME: this was a fallthrough condition.
@@ skipping 85 matching lines @@
 }
 
 bool SelectorChecker::matchesFocusPseudoClass(const Element& element)
 {
     if (InspectorInstrumentation::forcePseudoState(const_cast<Element*>(&element), CSSSelector::PseudoFocus))
         return true;
     return element.focused() && isFrameFocused(element);
 }
 
 }