Add support for new CSS ::slotted() pseudo element

third_party/WebKit/Source/core/css/parser/CSSSelectorParser.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "core/css/parser/CSSSelectorParser.h"
 
 #include "core/css/CSSSelectorList.h"
 #include "core/css/StyleSheetContents.h"
 #include "core/frame/UseCounter.h"
 #include "platform/RuntimeEnabledFeatures.h"
 
 namespace blink {
 
 static void recordSelectorStats(const CSSParserContext& context, const CSSSelectorList& selectorList)
 {
     if (!context.useCounter())
         return;
 
     for (const CSSSelector* selector = selectorList.first(); selector; selector = CSSSelectorList::next(*selector)) {
         for (const CSSSelector* current = selector; current ; current = current->tagHistory()) {
             UseCounter::Feature feature = UseCounter::NumberOfFeatures;
             switch (current->pseudoType()) {
             case CSSSelector::PseudoUnresolved:
                 feature = UseCounter::CSSSelectorPseudoUnresolved;
                 break;
+            case CSSSelector::PseudoSlotted:
+                feature = UseCounter::CSSSelectorPseudoSlotted;
+                break;
             case CSSSelector::PseudoContent:
                 feature = UseCounter::CSSSelectorPseudoContent;
                 break;
             case CSSSelector::PseudoHost:
                 feature = UseCounter::CSSSelectorPseudoHost;
                 break;
             case CSSSelector::PseudoHostContext:
                 feature = UseCounter::CSSSelectorPseudoHostContext;
                 break;
             case CSSSelector::PseudoFullScreenAncestor:
@@ skipping 331 matching lines @@
         {
             OwnPtr<CSSParserSelector> innerSelector = consumeCompoundSelector(block);
             block.consumeWhitespace();
             if (!innerSelector || !innerSelector->isSimple() || !block.atEnd())
                 return nullptr;
             Vector<OwnPtr<CSSParserSelector>> selectorVector;
             selectorVector.append(innerSelector.release());
             selector->adoptSelectorVector(selectorVector);
             return selector.release();
         }
+    case CSSSelector::PseudoSlotted:
+        {
+            DisallowPseudoElementsScope scope(this);
+
+            OwnPtr<CSSParserSelector> innerSelector = consumeCompoundSelector(block);
+            block.consumeWhitespace();
+            if (!innerSelector || !block.atEnd())
+                return nullptr;
+            Vector<OwnPtr<CSSParserSelector>> selectorVector;
+            selectorVector.append(innerSelector.release());
+            selector->adoptSelectorVector(selectorVector);
+            selector->setRelationIsAffectedByPseudoSlotted();
+            return selector.release();
+        }
     case CSSSelector::PseudoLang:
         {
             // FIXME: CSS Selectors Level 4 allows :lang(*-foo)
             const CSSParserToken& ident = block.consumeIncludingWhitespace();
             if (ident.type() != IdentToken || !block.atEnd())
                 return nullptr;
             selector->setArgument(ident.value());
             return selector.release();
         }
     case CSSSelector::PseudoNthChild:
@@ skipping 173 matching lines @@
 
 const AtomicString& CSSSelectorParser::determineNamespace(const AtomicString& prefix)
 {
     if (!m_styleSheet)
         return defaultNamespace();
     return m_styleSheet->determineNamespace(prefix);
 }
 
 void CSSSelectorParser::prependTypeSelectorIfNeeded(const AtomicString& namespacePrefix, const AtomicString& elementName, CSSParserSelector* compoundSelector)
 {
-    if (elementName.isNull() && defaultNamespace() == starAtom && !compoundSelector->needsImplicitShadowCrossingCombinatorForMatching())
+    if (elementName.isNull() && defaultNamespace() == starAtom && !compoundSelector->needsImplicitShadowCrossingCombinatorForMatching() && !compoundSelector->relationIsAffectedByPseudoSlotted())
         return;
 
     AtomicString determinedElementName = elementName.isNull() ? starAtom : elementName;
     AtomicString namespaceURI = determineNamespace(namespacePrefix);
     if (namespaceURI.isNull())
         return;
     QualifiedName tag = QualifiedName(namespacePrefix, determinedElementName, namespaceURI);
 
     if (compoundSelector->needsImplicitShadowCrossingCombinatorForMatching())
         return rewriteSpecifiersWithElementNameForCustomPseudoElement(tag, compoundSelector, elementName.isNull());
 
-    if (compoundSelector->pseudoType() == CSSSelector::PseudoContent)
-        return rewriteSpecifiersWithElementNameForContentPseudoElement(tag, compoundSelector, elementName.isNull());
+    if (compoundSelector->pseudoType() == CSSSelector::PseudoContent || compoundSelector->pseudoType() == CSSSelector::PseudoSlotted)
+        return rewriteSpecifiersWithElementNameForContentOrSlottedPseudoElement(tag, compoundSelector, elementName.isNull());
 
     // *:host never matches, so we can't discard the * otherwise we can't tell the
     // difference between *:host and just :host.
     if (tag == anyQName() && !compoundSelector->hasHostPseudoSelector())
         return;
     compoundSelector->prependTagSelector(tag, elementName.isNull());
 }
 
 void CSSSelectorParser::rewriteSpecifiersWithElementNameForCustomPseudoElement(const QualifiedName& tag, CSSParserSelector* specifiers, bool tagIsImplicit)
 {
@@ skipping 14 matching lines @@
         return;
     }
 
     // For shadow-ID pseudo-elements to be correctly matched, the ShadowPseudo combinator has to be used.
     // We therefore create a new Selector with that combinator here in any case, even if matching any (host) element in any namespace (i.e. '*').
     OwnPtr<CSSParserSelector> elementNameSelector = CSSParserSelector::create(tag);
     lastShadowPseudo->setTagHistory(elementNameSelector.release());
     lastShadowPseudo->setRelation(CSSSelector::ShadowPseudo);
 }
 
-void CSSSelectorParser::rewriteSpecifiersWithElementNameForContentPseudoElement(const QualifiedName& tag, CSSParserSelector* specifiers, bool tagIsImplicit)
+void CSSSelectorParser::rewriteSpecifiersWithElementNameForContentOrSlottedPseudoElement(const QualifiedName& tag, CSSParserSelector* specifiers, bool tagIsImplicit)
 {
     CSSParserSelector* last = specifiers;
     CSSParserSelector* history = specifiers;
     while (history->tagHistory()) {
         history = history->tagHistory();
-        if (history->pseudoType() == CSSSelector::PseudoContent || history->relationIsAffectedByPseudoContent())
+        if (history->pseudoType() == CSSSelector::PseudoContent || history->relationIsAffectedByPseudoContent()
+            || history->pseudoType() == CSSSelector::PseudoSlotted || history->relationIsAffectedByPseudoSlotted())
             last = history;
     }
 
     if (last->tagHistory()) {
         if (tag != anyQName())
             last->tagHistory()->prependTagSelector(tag, tagIsImplicit);
         return;
     }
 
-    // For shadow-ID pseudo-elements to be correctly matched, the ShadowPseudo combinator has to be used.
-    // We therefore create a new Selector with that combinator here in any case, even if matching any (host) element in any namespace (i.e. '*').
     OwnPtr<CSSParserSelector> elementNameSelector = CSSParserSelector::create(tag);
     last->setTagHistory(elementNameSelector.release());
+    if (last->pseudoType() == CSSSelector::PseudoSlotted)
+        last->setRelation(CSSSelector::ShadowSlot);
 }
 
 PassOwnPtr<CSSParserSelector> CSSSelectorParser::addSimpleSelectorToCompound(PassOwnPtr<CSSParserSelector> compoundSelector, PassOwnPtr<CSSParserSelector> simpleSelector)
 {
     // The tagHistory is a linked list that stores combinator separated compound selectors
     // from right-to-left. Yet, within a single compound selector, stores the simple selectors
     // from left-to-right.
     //
     // ".a.b > div#id" is stored in a tagHistory as [div, #id, .a, .b], each element in the
     // list stored with an associated relation (combinator or SubSelector).
@@ skipping 33 matching lines @@
         compoundSelector->insertTagHistory(CSSSelector::SubSelector, simpleSelector, relation);
         return compoundSelector;
     }
 
     // All other simple selectors are added to the end of the compound.
     compoundSelector->appendTagHistory(CSSSelector::SubSelector, simpleSelector);
     return compoundSelector;
 }
 
 } // namespace blink