Implement proposed shadow tree cascade order.

Source/core/css/resolver/StyleResolver.cpp

Index: Source/core/css/resolver/StyleResolver.cpp
diff --git a/Source/core/css/resolver/StyleResolver.cpp b/Source/core/css/resolver/StyleResolver.cpp
index 57f33842d5b36cd49c3ec1a293008548b1376e85..467daa83a4547fb4ceec5602f2ee7f9079fab59a 100644
--- a/Source/core/css/resolver/StyleResolver.cpp
+++ b/Source/core/css/resolver/StyleResolver.cpp
@@ -123,21 +123,6 @@ static StylePropertySet* rightToLeftDeclaration()
     return rightToLeftDecl;
 }
 
-static void collectScopedResolversForHostedShadowTrees(const Element* element, WillBeHeapVector<RawPtrWillBeMember<ScopedStyleResolver>, 8>& resolvers)
-{
-    ElementShadow* shadow = element->shadow();
-    if (!shadow)
-        return;
-
-    // Adding scoped resolver for active shadow roots for shadow host styling.
-    for (ShadowRoot* shadowRoot = shadow->youngestShadowRoot(); shadowRoot; shadowRoot = shadowRoot->olderShadowRoot()) {
-        if (shadowRoot->numberOfStyles() > 0) {
-            if (ScopedStyleResolver* resolver = shadowRoot->scopedStyleResolver())
-                resolvers.append(resolver);
-        }
-    }
-}
-
 StyleResolver::StyleResolver(Document& document)
     : m_document(document)
     , m_viewportStyleResolver(ViewportStyleResolver::create(&document))
@@ -237,12 +222,12 @@ void StyleResolver::resetRuleFeatures()
 
 void StyleResolver::addTreeBoundaryCrossingScope(ContainerNode& scope)
 {
-    m_treeBoundaryCrossingRules.addScope(scope);
+    m_treeBoundaryCrossingScopes.add(&scope);
 }
 
 void StyleResolver::resetAuthorStyle(TreeScope& treeScope)
 {
-    m_treeBoundaryCrossingRules.removeScope(treeScope.rootNode());
+    m_treeBoundaryCrossingScopes.remove(&treeScope.rootNode());
 
     ScopedStyleResolver* resolver = treeScope.scopedStyleResolver();
     if (!resolver)
@@ -343,11 +328,11 @@ StyleResolver::~StyleResolver()
 {
 }
 
-static inline ScopedStyleResolver* scopedResolverFor(const Element* element)
+static inline ScopedStyleResolver* scopedResolverFor(const Element& element)
 {
     // Ideally, returning element->treeScope().scopedStyleResolver() should be
     // enough, but ::cue and custom pseudo elements like ::-webkit-meter-bar pierce
-    // through a shadow dom boundary, yet they are not part of m_treeBoundaryCrossingRules.
+    // through a shadow dom boundary, yet they are not part of m_treeBoundaryCrossingScopes.
     // The assumption here is that these rules only pierce through one boundary and
     // that the scope of these elements do not have a style resolver due to the fact
     // that VTT scopes and UA shadow trees don't have <style> elements. This is
@@ -356,40 +341,82 @@ static inline ScopedStyleResolver* scopedResolverFor(const Element* element)
     // FIXME: Make ::cue and custom pseudo elements part of boundary crossing rules
     // when moving those rules to ScopedStyleResolver as part of issue 401359.
 
-    TreeScope* treeScope = &element->treeScope();
+    TreeScope* treeScope = &element.treeScope();
     if (ScopedStyleResolver* resolver = treeScope->scopedStyleResolver()) {
-        ASSERT(element->shadowPseudoId().isEmpty());
-        ASSERT(!element->isVTTElement());
+        ASSERT(element.shadowPseudoId().isEmpty());
+        ASSERT(!element.isVTTElement());
         return resolver;
     }
 
     treeScope = treeScope->parentTreeScope();
     if (!treeScope)
         return nullptr;
-    if (element->shadowPseudoId().isEmpty() && !element->isVTTElement())
+    if (element.shadowPseudoId().isEmpty() && !element.isVTTElement())
         return nullptr;
     return treeScope->scopedStyleResolver();
 }
 
-void StyleResolver::matchAuthorRules(Element* element, ElementRuleCollector& collector, bool includeEmptyRules)
+void StyleResolver::matchHostRules(const Element& element, ElementRuleCollector& collector, bool includeEmptyRules)
 {
-    collector.clearMatchedRules();
+    ElementShadow* shadow = element.shadow();
+    if (!shadow)
+        return;
 
-    CascadeOrder cascadeOrder = 0;
-    WillBeHeapVector<RawPtrWillBeMember<ScopedStyleResolver>, 8> resolversInShadowTree;
-    collectScopedResolversForHostedShadowTrees(element, resolversInShadowTree);
+    // Adding scoped resolvers for active shadow roots for shadow host styling.
+    for (ShadowRoot* shadowRoot = shadow->oldestShadowRoot(); shadowRoot; shadowRoot = shadowRoot->youngerShadowRoot()) {
+        if (!shadowRoot->numberOfStyles())
+            continue;
+        if (ScopedStyleResolver* resolver = shadowRoot->scopedStyleResolver()) {
+            collector.clearMatchedRules();
+            resolver->collectMatchingShadowHostRules(collector, includeEmptyRules);
+            collector.sortAndTransferMatchedRules();
+            collector.closeOriginOrScope();
+        }
+    }
+}
 
-    // Apply :host and :host-context rules from inner scopes.
-    for (int j = resolversInShadowTree.size() - 1; j >= 0; --j)
-        resolversInShadowTree.at(j)->collectMatchingShadowHostRules(collector, includeEmptyRules, ++cascadeOrder);
+ScopedStyleResolver* StyleResolver::matchElementScopeRules(const Element& element, ElementRuleCollector& collector, bool includeEmptyRules)

[kochi, 2015/08/10 12:15:03]

Can this be a static function, rather than a private member function of
StyleResolver?

+{
+    ScopedStyleResolver* resolver = scopedResolverFor(element);
+    if (resolver) {
+        collector.clearMatchedRules();
+        resolver->collectMatchingAuthorRules(collector, includeEmptyRules);
+        resolver->collectMatchingTreeBoundaryCrossingRules(collector, includeEmptyRules);
+        collector.sortAndTransferMatchedRules();
+    }
+    collector.closeOriginOrScope();
+    return resolver;
+}
 
-    // Apply normal rules from element scope.
-    if (ScopedStyleResolver* resolver = scopedResolverFor(element))
-        resolver->collectMatchingAuthorRules(collector, includeEmptyRules, ++cascadeOrder);
+void StyleResolver::matchScopedRules(const Element& element, ElementRuleCollector& collector, bool includeEmptyRules)
+{
+    bool matchElementScope = true;
 
-    // Apply /deep/ and ::shadow rules from outer scopes, and ::content from inner.
-    m_treeBoundaryCrossingRules.collectTreeBoundaryCrossingRules(element, collector, includeEmptyRules);
-    collector.sortAndTransferMatchedRules();
+    for (auto it = m_treeBoundaryCrossingScopes.rbegin(); it != m_treeBoundaryCrossingScopes.rend(); ++it) {
+        const TreeScope& scope = (*it)->treeScope();
+        ScopedStyleResolver* resolver = scope.scopedStyleResolver();
+        ASSERT(resolver);
+
+        if (matchElementScope && scope.isInclusiveAncestorOf(element.treeScope())) {
+            matchElementScope = false;
+            if (matchElementScopeRules(element, collector, includeEmptyRules) == resolver)
+                continue;
+        }
+
+        collector.clearMatchedRules();
+        resolver->collectMatchingTreeBoundaryCrossingRules(collector, includeEmptyRules);
+        collector.sortAndTransferMatchedRules();
+        collector.closeOriginOrScope();
+    }
+
+    if (matchElementScope)
+        matchElementScopeRules(element, collector, includeEmptyRules);
+}
+
+void StyleResolver::matchAuthorRules(const Element& element, ElementRuleCollector& collector, bool includeEmptyRules)
+{
+    matchHostRules(element, collector, includeEmptyRules);
+    matchScopedRules(element, collector, includeEmptyRules);
 }
 
 void StyleResolver::matchUARules(ElementRuleCollector& collector)
@@ -408,6 +435,7 @@ void StyleResolver::matchUARules(ElementRuleCollector& collector)
     if (document().isViewSource())
         matchRuleSet(collector, defaultStyleSheets.defaultViewSourceStyle());
 
+    collector.closeOriginOrScope();
     collector.setMatchingUARules(false);
 }
 
@@ -416,6 +444,7 @@ void StyleResolver::matchRuleSet(ElementRuleCollector& collector, RuleSet* rules
     collector.clearMatchedRules();
     collector.collectMatchingRules(MatchRequest(rules));
     collector.sortAndTransferMatchedRules();
+    collector.closeOriginOrScope();
 }
 
 void StyleResolver::matchAllRules(StyleResolverState& state, ElementRuleCollector& collector, bool includeSMILProperties)
@@ -441,9 +470,15 @@ void StyleResolver::matchAllRules(StyleResolverState& state, ElementRuleCollecto
         }
     }
 
-    matchAuthorRules(state.element(), collector, false);
+    matchAuthorRules(*state.element(), collector, false);
 
     if (state.element()->isStyledElement()) {
+        // TODO(rune@opera.com): Adding style attribute rules here is probably too late
+        // when you have shadow piercing combinators. When we don't have piercing combinators,
+        // the style attribute always belong to the outermost scope whose rules apply to
+        // the element. Thus, applying inline style here is correct. Fixing this for piercing
+        // combinators means moving the code below into matchElementScopeRules and _not_
+        // invoking it for pseudo style requests.
         if (state.element()->inlineStyle()) {
             // Inline style is immutable as long as there is no CSSOM wrapper.
             bool isInlineStyleCacheable = !state.element()->inlineStyle()->isMutable();
@@ -453,6 +488,8 @@ void StyleResolver::matchAllRules(StyleResolverState& state, ElementRuleCollecto
         // Now check SMIL animation override style.
         if (includeSMILProperties && state.element()->isSVGElement())
             collector.addElementStyleProperties(toSVGElement(state.element())->animatedSMILStyleProperties(), false /* isCacheable */);
+
+        collector.closeOriginOrScope();
     }
 }
 
@@ -747,9 +784,9 @@ bool StyleResolver::pseudoStyleForElementInternal(Element& element, const Pseudo
         collector.setPseudoStyleRequest(pseudoStyleRequest);
 
         matchUARules(collector);
-        matchAuthorRules(state.element(), collector, false);
+        matchAuthorRules(*state.element(), collector, false);
 
-        if (collector.matchedResult().matchedProperties.isEmpty())
+        if (!collector.matchedResult().hasMatchedProperties())
             return false;
 
         applyMatchedProperties(state, collector.matchedResult());
@@ -822,12 +859,12 @@ PassRefPtr<ComputedStyle> StyleResolver::styleForPage(int pageIndex)
     bool inheritedOnly = false;
 
     const MatchResult& result = collector.matchedResult();
-    applyMatchedProperties<HighPropertyPriority>(state, result, false, result.begin(), result.end(), inheritedOnly);
+    applyMatchedProperties<HighPropertyPriority>(state, result.allRules(), false, inheritedOnly);
 
     // If our font got dirtied, go ahead and update it now.
     updateFont(state);
 
-    applyMatchedProperties<LowPropertyPriority>(state, result, false, result.begin(), result.end(), inheritedOnly);
+    applyMatchedProperties<LowPropertyPriority>(state, result.allRules(), false, inheritedOnly);
 
     loadPendingResources(state);
 
@@ -897,7 +934,7 @@ void StyleResolver::collectPseudoRulesForElement(Element* element, ElementRuleCo
 
     if (rulesToInclude & AuthorCSSRules) {
         collector.setSameOriginOnly(!(rulesToInclude & CrossOriginCSSRules));
-        matchAuthorRules(element, collector, rulesToInclude & EmptyCSSRules);
+        matchAuthorRules(*element, collector, rulesToInclude & EmptyCSSRules);
     }
 }
 
@@ -940,10 +977,25 @@ bool StyleResolver::applyAnimatedProperties(StyleResolverState& state, const Ele
     return true;
 }
 
+static void collectScopedResolversForHostedShadowTrees(const Element& element, WillBeHeapVector<RawPtrWillBeMember<ScopedStyleResolver>, 8>& resolvers)
+{
+    ElementShadow* shadow = element.shadow();
+    if (!shadow)
+        return;
+
+    // Adding scoped resolver for active shadow roots for shadow host styling.
+    for (ShadowRoot* shadowRoot = shadow->youngestShadowRoot(); shadowRoot; shadowRoot = shadowRoot->olderShadowRoot()) {
+        if (shadowRoot->numberOfStyles() > 0) {
+            if (ScopedStyleResolver* resolver = shadowRoot->scopedStyleResolver())
+                resolvers.append(resolver);
+        }
+    }
+}
+
 StyleRuleKeyframes* StyleResolver::findKeyframesRule(const Element* element, const AtomicString& animationName)
 {
     WillBeHeapVector<RawPtrWillBeMember<ScopedStyleResolver>, 8> resolvers;
-    collectScopedResolversForHostedShadowTrees(element, resolvers);
+    collectScopedResolversForHostedShadowTrees(*element, resolvers);
     if (ScopedStyleResolver* scopedResolver = element->treeScope().scopedStyleResolver())
         resolvers.append(scopedResolver);
 
@@ -1225,16 +1277,13 @@ void StyleResolver::applyProperties(StyleResolverState& state, const StyleProper
 }
 
 template <CSSPropertyPriority priority>
-void StyleResolver::applyMatchedProperties(StyleResolverState& state, const MatchResult& matchResult, bool isImportant, unsigned startIndex, unsigned endIndex, bool inheritedOnly)
+void StyleResolver::applyMatchedProperties(StyleResolverState& state, const MatchedPropertiesRange& range, bool isImportant, bool inheritedOnly)
 {
-    if (startIndex == endIndex)
+    if (range.begin() == range.end())
         return;
 
-    ASSERT_WITH_SECURITY_IMPLICATION(endIndex <= matchResult.matchedProperties.size());
-
     if (state.style()->insideLink() != NotInsideLink) {
-        for (unsigned i = startIndex; i < endIndex; ++i) {
-            const MatchedProperties& matchedProperties = matchResult.matchedProperties[i];
+        for (const auto& matchedProperties : range) {
             unsigned linkMatchType = matchedProperties.m_types.linkMatchType;
             // FIXME: It would be nicer to pass these as arguments but that requires changes in many places.
             state.setApplyPropertyToRegularStyle(linkMatchType & CSSSelector::MatchLink);
@@ -1246,10 +1295,8 @@ void StyleResolver::applyMatchedProperties(StyleResolverState& state, const Matc
         state.setApplyPropertyToVisitedLinkStyle(false);
         return;
     }
-    for (unsigned i = startIndex; i < endIndex; ++i) {
-        const MatchedProperties& matchedProperties = matchResult.matchedProperties[i];
+    for (const auto& matchedProperties : range)
         applyProperties<priority>(state, matchedProperties.properties.get(), isImportant, inheritedOnly, static_cast<PropertyWhitelistType>(matchedProperties.m_types.whitelistType));
-    }
 }
 
 static unsigned computeMatchedPropertiesHash(const MatchedProperties* properties, unsigned size)
@@ -1275,9 +1322,9 @@ void StyleResolver::applyMatchedProperties(StyleResolverState& state, const Matc
 
     INCREMENT_STYLE_STATS_COUNTER(*this, matchedPropertyApply, 1);
 
-    unsigned cacheHash = matchResult.isCacheable ? computeMatchedPropertiesHash(matchResult.matchedProperties.data(), matchResult.matchedProperties.size()) : 0;
+    unsigned cacheHash = matchResult.isCacheable() ? computeMatchedPropertiesHash(matchResult.matchedProperties().data(), matchResult.matchedProperties().size()) : 0;
     bool applyInheritedOnly = false;
-    const CachedMatchedProperties* cachedMatchedProperties = cacheHash ? m_matchedPropertiesCache.find(cacheHash, state, matchResult) : 0;
+    const CachedMatchedProperties* cachedMatchedProperties = cacheHash ? m_matchedPropertiesCache.find(cacheHash, state, matchResult.matchedProperties()) : 0;
 
     if (cachedMatchedProperties && MatchedPropertiesCache::isCacheable(element, *state.style(), *state.parentStyle())) {
         INCREMENT_STYLE_STATS_COUNTER(*this, matchedPropertyCacheHit, 1);
@@ -1308,9 +1355,10 @@ void StyleResolver::applyMatchedProperties(StyleResolverState& state, const Matc
     // high-priority properties first, i.e., those properties that other properties depend on.
     // The order is (1) high-priority not important, (2) high-priority important, (3) normal not important
     // and (4) normal important.
-    applyMatchedProperties<HighPropertyPriority>(state, matchResult, false, matchResult.begin(), matchResult.end(), applyInheritedOnly);
-    applyMatchedProperties<HighPropertyPriority>(state, matchResult, true, matchResult.beginAuthor(), matchResult.endAuthor(), applyInheritedOnly);
-    applyMatchedProperties<HighPropertyPriority>(state, matchResult, true, matchResult.beginUA(), matchResult.endUA(), applyInheritedOnly);
+    applyMatchedProperties<HighPropertyPriority>(state, matchResult.allRules(), false, applyInheritedOnly);
+    for (auto range : ImportantAuthorRanges(matchResult))
+        applyMatchedProperties<HighPropertyPriority>(state, range, true, applyInheritedOnly);
+    applyMatchedProperties<HighPropertyPriority>(state, matchResult.uaRules(), true, applyInheritedOnly);
 
     if (UNLIKELY(isSVGForeignObjectElement(element))) {
         // LayoutSVGRoot handles zooming for the whole SVG subtree, so foreignObject content should not be scaled again.
@@ -1336,21 +1384,22 @@ void StyleResolver::applyMatchedProperties(StyleResolverState& state, const Matc
         applyInheritedOnly = false;
 
     // Now do the normal priority UA properties.
-    applyMatchedProperties<LowPropertyPriority>(state, matchResult, false, matchResult.beginUA(), matchResult.endUA(), applyInheritedOnly);
+    applyMatchedProperties<LowPropertyPriority>(state, matchResult.uaRules(), false, applyInheritedOnly);
 
     // Cache the UA properties to pass them to LayoutTheme in adjustComputedStyle.
     state.cacheUserAgentBorderAndBackground();
 
     // Now do the author and user normal priority properties and all the !important properties.
-    applyMatchedProperties<LowPropertyPriority>(state, matchResult, false, matchResult.beginAuthor(), matchResult.endAuthor(), applyInheritedOnly);
-    applyMatchedProperties<LowPropertyPriority>(state, matchResult, true, matchResult.beginAuthor(), matchResult.endAuthor(), applyInheritedOnly);
-    applyMatchedProperties<LowPropertyPriority>(state, matchResult, true, matchResult.beginUA(), matchResult.endUA(), applyInheritedOnly);
+    applyMatchedProperties<LowPropertyPriority>(state, matchResult.authorRules(), false, applyInheritedOnly);
+    for (auto range : ImportantAuthorRanges(matchResult))
+        applyMatchedProperties<LowPropertyPriority>(state, range, true, applyInheritedOnly);
+    applyMatchedProperties<LowPropertyPriority>(state, matchResult.uaRules(), true, applyInheritedOnly);
 
     loadPendingResources(state);
 
     if (!cachedMatchedProperties && cacheHash && MatchedPropertiesCache::isCacheable(element, *state.style(), *state.parentStyle())) {
         INCREMENT_STYLE_STATS_COUNTER(*this, matchedPropertyCacheAdded, 1);
-        m_matchedPropertiesCache.add(*state.style(), *state.parentStyle(), cacheHash, matchResult);
+        m_matchedPropertiesCache.add(*state.style(), *state.parentStyle(), cacheHash, matchResult.matchedProperties());
     }
 
     ASSERT(!state.fontBuilder().fontDirty());
@@ -1437,7 +1486,7 @@ DEFINE_TRACE(StyleResolver)
     visitor->trace(m_siblingRuleSet);
     visitor->trace(m_uncommonAttributeRuleSet);
     visitor->trace(m_watchedSelectorsRules);
-    visitor->trace(m_treeBoundaryCrossingRules);
+    visitor->trace(m_treeBoundaryCrossingScopes);
     visitor->trace(m_styleResourceLoader);
     visitor->trace(m_styleSharingLists);
     visitor->trace(m_pendingStyleSheets);