Have ElementTraversal::firstWithin() take a reference

Source/core/dom/SelectorQuery.cpp

 /*
  * Copyright (C) 2011 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 46 matching lines @@
         m_currentNode = 0;
         return current;
     }
 
 private:
     Node* m_currentNode;
 };
 
 class ClassRootNodeList : public SimpleNodeList {
 public:
-    ClassRootNodeList(Node* rootNode, const AtomicString& className)
+    ClassRootNodeList(Node& rootNode, const AtomicString& className)
         : m_className(className)
         , m_rootNode(rootNode)
         , m_currentElement(nextInternal(ElementTraversal::firstWithin(m_rootNode))) { }
 
     bool isEmpty() const { return !m_currentElement; }
 
     Node* next()
     {
         Node* current = m_currentElement;
         ASSERT(current);
-        m_currentElement = nextInternal(ElementTraversal::nextSkippingChildren(*m_currentElement, m_rootNode));
+        m_currentElement = nextInternal(ElementTraversal::nextSkippingChildren(*m_currentElement, &m_rootNode));
         return current;
     }
 
 private:
     Element* nextInternal(Element* element)
     {
-        for (; element; element = ElementTraversal::next(*element, m_rootNode)) {
+        for (; element; element = ElementTraversal::next(*element, &m_rootNode)) {
             if (element->hasClass() && element->classNames().contains(m_className))
                 return element;
         }
         return 0;
     }
 
     const AtomicString& m_className;
-    Node* m_rootNode;
+    Node& m_rootNode;
     Element* m_currentElement;
 };
 
 class ClassElementList : public SimpleNodeList {
 public:
-    ClassElementList(Node* rootNode, const AtomicString& className)
+    ClassElementList(Node& rootNode, const AtomicString& className)
         : m_className(className)
         , m_rootNode(rootNode)
         , m_currentElement(nextInternal(ElementTraversal::firstWithin(rootNode))) { }
 
     bool isEmpty() const { return !m_currentElement; }
 
     Node* next()
     {
         Node* current = m_currentElement;
         ASSERT(current);
-        m_currentElement = nextInternal(ElementTraversal::next(*m_currentElement, m_rootNode));
+        m_currentElement = nextInternal(ElementTraversal::next(*m_currentElement, &m_rootNode));
         return current;
     }
 
 private:
     Element* nextInternal(Element* element)
     {
-        for (; element; element = ElementTraversal::next(*element, m_rootNode)) {
+        for (; element; element = ElementTraversal::next(*element, &m_rootNode)) {
             if (element->hasClass() && element->classNames().contains(m_className))
                 return element;
         }
         return 0;
     }
 
     const AtomicString& m_className;
-    Node* m_rootNode;
+    Node& m_rootNode;
     Element* m_currentElement;
 };
 
 void SelectorDataList::initialize(const CSSSelectorList& selectorList)
 {
     ASSERT(m_selectors.isEmpty());
 
     unsigned selectorCount = 0;
     for (const CSSSelector* selector = selectorList.first(); selector; selector = CSSSelectorList::next(selector))
         selectorCount++;
@@ skipping 44 matching lines @@
 }
 
 static inline bool isTreeScopeRoot(Node* node)
 {
     ASSERT(node);
     return node->isDocumentNode() || node->isShadowRoot();
 }
 
 void SelectorDataList::collectElementsByClassName(Node& rootNode, const AtomicString& className, Vector<RefPtr<Node> >& traversalRoots) const
 {
-    for (Element* element = ElementTraversal::firstWithin(&rootNode); element; element = ElementTraversal::next(*element, &rootNode)) {
+    for (Element* element = ElementTraversal::firstWithin(rootNode); element; element = ElementTraversal::next(*element, &rootNode)) {
         if (element->hasClass() && element->classNames().contains(className))
             traversalRoots.append(element);
     }
 }
 
 void SelectorDataList::collectElementsByTagName(Node& rootNode, const QualifiedName& tagName, Vector<RefPtr<Node> >& traversalRoots) const
 {
-    for (Element* element = ElementTraversal::firstWithin(&rootNode); element; element = ElementTraversal::next(*element, &rootNode)) {
+    for (Element* element = ElementTraversal::firstWithin(rootNode); element; element = ElementTraversal::next(*element, &rootNode)) {
         if (SelectorChecker::tagMatches(*element, tagName))
             traversalRoots.append(element);
     }
 }
 
 Element* SelectorDataList::findElementByClassName(Node& rootNode, const AtomicString& className) const
 {
-    for (Element* element = ElementTraversal::firstWithin(&rootNode); element; element = ElementTraversal::next(*element, &rootNode)) {
+    for (Element* element = ElementTraversal::firstWithin(rootNode); element; element = ElementTraversal::next(*element, &rootNode)) {
         if (element->hasClass() && element->classNames().contains(className))
             return element;
     }
     return 0;
 }
 
 Element* SelectorDataList::findElementByTagName(Node& rootNode, const QualifiedName& tagName) const
 {
-    for (Element* element = ElementTraversal::firstWithin(&rootNode); element; element = ElementTraversal::next(*element, &rootNode)) {
+    for (Element* element = ElementTraversal::firstWithin(rootNode); element; element = ElementTraversal::next(*element, &rootNode)) {
         if (SelectorChecker::tagMatches(*element, tagName))
             return element;
     }
     return 0;
 }
 
 inline bool SelectorDataList::canUseFastQuery(const Node& rootNode) const
 {
     return m_selectors.size() == 1 && rootNode.inDocument() && !rootNode.document().inQuirksMode();
 }
 
-inline bool ancestorHasClassName(Node* rootNode, const AtomicString& className)
+inline bool ancestorHasClassName(Node& rootNode, const AtomicString& className)
 {
-    if (!rootNode->isElementNode())
+    if (!rootNode.isElementNode())
         return false;
 
-    for (Element* element = toElement(rootNode); element; element = element->parentElement()) {
+    for (Element* element = &toElement(rootNode); element; element = element->parentElement()) {
         if (element->hasClass() && element->classNames().contains(className))
             return true;
     }
     return false;
 }
 
 
 // If returns true, traversalRoots has the elements that may match the selector query.
 //
 // If returns false, traversalRoots has the rootNode parameter or descendants of rootNode representing
 // the subtree for which we can limit the querySelector traversal.
 //
 // The travseralRoots may be empty, regardless of the returned bool value, if this method finds that the selectors won't
 // match any element.
-PassOwnPtr<SimpleNodeList> SelectorDataList::findTraverseRoots(Node* rootNode, bool& matchTraverseRoots) const
+PassOwnPtr<SimpleNodeList> SelectorDataList::findTraverseRoots(Node& rootNode, bool& matchTraverseRoots) const
 {
     // We need to return the matches in document order. To use id lookup while there is possiblity of multiple matches
     // we would need to sort the results. For now, just traverse the document in that case.
-    ASSERT(rootNode);
     ASSERT(m_selectors.size() == 1);
     ASSERT(m_selectors[0].selector);
 
     bool isRightmostSelector = true;
     bool startFromParent = false;
 
     for (const CSSSelector* selector = m_selectors[0].selector; selector; selector = selector->tagHistory()) {
-        if (selector->m_match == CSSSelector::Id && !rootNode->document().containsMultipleElementsWithId(selector->value())) {
-            Element* element = rootNode->treeScope().getElementById(selector->value());
-            if (element && (isTreeScopeRoot(rootNode) || element->isDescendantOf(rootNode)))
-                rootNode = element;
+        if (selector->m_match == CSSSelector::Id && !rootNode.document().containsMultipleElementsWithId(selector->value())) {
+            Element* element = rootNode.treeScope().getElementById(selector->value());
+            Node* adjustedNode = &rootNode;
+            if (element && (isTreeScopeRoot(&rootNode) || element->isDescendantOf(&rootNode)))
+                adjustedNode = element;
             else if (!element || isRightmostSelector)
-                rootNode = 0;
+                adjustedNode = 0;
             if (isRightmostSelector) {
                 matchTraverseRoots = true;
-                return adoptPtr(new SingleNodeList(rootNode));
+                return adoptPtr(new SingleNodeList(adjustedNode));
             }
-            if (startFromParent && rootNode)
-                rootNode = rootNode->parentNode();
+            if (startFromParent && adjustedNode)
+                adjustedNode = adjustedNode->parentNode();
 
             matchTraverseRoots = false;
-            return adoptPtr(new SingleNodeList(rootNode));
+            return adoptPtr(new SingleNodeList(adjustedNode));
         }
 
         // If we have both CSSSelector::Id and CSSSelector::Class at the same time, we should use Id
         // to find traverse root.
         if (!startFromParent && selector->m_match == CSSSelector::Class) {
             if (isRightmostSelector) {
                 matchTraverseRoots = true;
                 return adoptPtr(new ClassElementList(rootNode, selector->value()));
             }
             matchTraverseRoots = false;
             // Since there exists some ancestor element which has the class name, we need to see all children of rootNode.
             if (ancestorHasClassName(rootNode, selector->value()))
-                return adoptPtr(new SingleNodeList(rootNode));
+                return adoptPtr(new SingleNodeList(&rootNode));
 
             return adoptPtr(new ClassRootNodeList(rootNode, selector->value()));
         }
 
         if (selector->relation() == CSSSelector::SubSelector)
             continue;
         isRightmostSelector = false;
         if (selector->relation() == CSSSelector::DirectAdjacent || selector->relation() == CSSSelector::IndirectAdjacent)
             startFromParent = true;
         else
             startFromParent = false;
     }
 
     matchTraverseRoots = false;
-    return adoptPtr(new SingleNodeList(rootNode));
+    return adoptPtr(new SingleNodeList(&rootNode));
 }
 
 void SelectorDataList::executeSlowQueryAll(Node& rootNode, Vector<RefPtr<Node> >& matchedElements) const
 {
-    for (Element* element = ElementTraversal::firstWithin(&rootNode); element; element = ElementTraversal::next(*element, &rootNode)) {
+    for (Element* element = ElementTraversal::firstWithin(rootNode); element; element = ElementTraversal::next(*element, &rootNode)) {
         for (unsigned i = 0; i < m_selectors.size(); ++i) {
             if (selectorMatches(m_selectors[i], *element, rootNode)) {
                 matchedElements.append(element);
                 break;
             }
         }
     }
 }
 
 void SelectorDataList::executeQueryAll(Node& rootNode, Vector<RefPtr<Node> >& matchedElements) const
@@ skipping 23 matching lines @@
         case CSSSelector::Class:
             return collectElementsByClassName(rootNode, firstSelector->value(), matchedElements);
         case CSSSelector::Tag:
             return collectElementsByTagName(rootNode, firstSelector->tagQName(), matchedElements);
         default:
             break; // If we need another fast path, add here.
         }
     }
 
     bool matchTraverseRoots;
-    OwnPtr<SimpleNodeList> traverseRoots = findTraverseRoots(&rootNode, matchTraverseRoots);
+    OwnPtr<SimpleNodeList> traverseRoots = findTraverseRoots(rootNode, matchTraverseRoots);
     if (traverseRoots->isEmpty())
         return;
 
     const SelectorData& selector = m_selectors[0];
     if (matchTraverseRoots) {
         while (!traverseRoots->isEmpty()) {
             Node& node = *traverseRoots->next();
             Element& element = toElement(node);
             if (selectorMatches(selector, element, rootNode))
                 matchedElements.append(&element);
         }
         return;
     }
 
     while (!traverseRoots->isEmpty()) {
         Node* traverseRoot = traverseRoots->next();
-        for (Element* element = ElementTraversal::firstWithin(traverseRoot); element; element = ElementTraversal::next(*element, traverseRoot)) {
+        ASSERT(traverseRoot);
+        for (Element* element = ElementTraversal::firstWithin(*traverseRoot); element; element = ElementTraversal::next(*element, traverseRoot)) {
             if (selectorMatches(selector, *element, rootNode))
                 matchedElements.append(element);
         }
     }
 }
 
 // If matchTraverseRoot is true, the returned Node is the single Element that may match the selector query.
 //
 // If matchTraverseRoot is false, the returned Node is the rootNode parameter or a descendant of rootNode representing
 // the subtree for which we can limit the querySelector traversal.
@@ skipping 33 matching lines @@
             startFromParent = true;
         else
             startFromParent = false;
     }
     matchTraverseRoot = false;
     return &rootNode;
 }
 
 Element* SelectorDataList::executeSlowQueryFirst(Node& rootNode) const
 {
-    for (Element* element = ElementTraversal::firstWithin(&rootNode); element; element = ElementTraversal::next(*element, &rootNode)) {
+    for (Element* element = ElementTraversal::firstWithin(rootNode); element; element = ElementTraversal::next(*element, &rootNode)) {
         for (unsigned i = 0; i < m_selectors.size(); ++i) {
             if (selectorMatches(m_selectors[i], *element, rootNode))
                 return element;
         }
     }
     return 0;
 }
 
 Element* SelectorDataList::executeQueryFirst(Node& rootNode) const
 {
@@ skipping 28 matching lines @@
     Node* traverseRootNode = findTraverseRoot(rootNode, matchTraverseRoot);
     if (!traverseRootNode)
         return 0;
     if (matchTraverseRoot) {
         ASSERT(m_selectors.size() == 1);
         ASSERT(traverseRootNode->isElementNode());
         Element& element = toElement(*traverseRootNode);
         return selectorMatches(m_selectors[0], element, rootNode) ? &element : 0;
     }
 
-    for (Element* element = ElementTraversal::firstWithin(traverseRootNode); element; element = ElementTraversal::next(*element, traverseRootNode)) {
+    for (Element* element = ElementTraversal::firstWithin(*traverseRootNode); element; element = ElementTraversal::next(*element, traverseRootNode)) {
         if (selectorMatches(m_selectors[0], *element, rootNode))
             return element;
     }
     return 0;
 }
 
 SelectorQuery::SelectorQuery(const CSSSelectorList& selectorList)
     : m_selectorList(selectorList)
 {
     m_selectors.initialize(m_selectorList);
@@ skipping 44 matching lines @@
     m_entries.add(selectors, selectorQuery.release());
     return rawSelectorQuery;
 }
 
 void SelectorQueryCache::invalidate()
 {
     m_entries.clear();
 }
 
 }