Have ElementTraversal / NodeTraversal's next() methods take a reference

Source/core/html/HTMLCollection.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2011, 2012 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
@@ skipping 288 matching lines @@
     if (type() == ChildNodeListType)
         return current;
     return iterateForPreviousNode(current);
 }
 
 template <class NodeListType>
 inline Element* firstMatchingElement(const NodeListType* nodeList, ContainerNode* root)
 {
     Element* element = ElementTraversal::firstWithin(root);
     while (element && !isMatchingElement(nodeList, element))
-        element = ElementTraversal::next(element, root);
+        element = ElementTraversal::next(*element, root);
     return element;
 }
 
 template <class NodeListType>
-inline Element* nextMatchingElement(const NodeListType* nodeList, Element* current, ContainerNode* root)
+inline Element* nextMatchingElement(const NodeListType* nodeList, Element& current, ContainerNode* root)
 {
+    Element* next = &current;
     do {
-        current = ElementTraversal::next(current, root);
-    } while (current && !isMatchingElement(nodeList, current));
-    return current;
+        next = ElementTraversal::next(*next, root);
+    } while (next && !isMatchingElement(nodeList, next));
+    return next;
 }
 
 template <class NodeListType>
-inline Element* traverseMatchingElementsForwardToOffset(const NodeListType* nodeList, unsigned offset, Element* currentElement, unsigned& currentOffset, ContainerNode* root)
+inline Element* traverseMatchingElementsForwardToOffset(const NodeListType* nodeList, unsigned offset, Element& currentElement, unsigned& currentOffset, ContainerNode* root)
 {
     ASSERT(currentOffset < offset);
-    while ((currentElement = nextMatchingElement(nodeList, currentElement, root))) {
+    Element* next = &currentElement;
+    while ((next = nextMatchingElement(nodeList, *next, root))) {
         if (++currentOffset == offset)
-            return currentElement;
+            return next;
     }
     return 0;
 }
 
 // FIXME: This should be in ChildNodeList
 inline Node* LiveNodeListBase::traverseChildNodeListForwardToOffset(unsigned offset, Node* currentNode, unsigned& currentOffset) const
 {
     ASSERT(type() == ChildNodeListType);
     ASSERT(currentOffset < offset);
     while ((currentNode = currentNode->nextSibling())) {
         if (++currentOffset == offset)
             return currentNode;
     }
     return 0;
 }
 
 // FIXME: This should be in LiveNodeList
 inline Element* LiveNodeListBase::traverseLiveNodeListFirstElement(ContainerNode* root) const
 {
     ASSERT(isNodeList(type()));
     ASSERT(type() != ChildNodeListType);
     if (type() == HTMLTagNodeListType)
         return firstMatchingElement(static_cast<const HTMLTagNodeList*>(this), root);
     if (type() == ClassNodeListType)
         return firstMatchingElement(static_cast<const ClassNodeList*>(this), root);
     return firstMatchingElement(static_cast<const LiveNodeList*>(this), root);
 }
 
 // FIXME: This should be in LiveNodeList
-inline Element* LiveNodeListBase::traverseLiveNodeListForwardToOffset(unsigned offset, Element* currentElement, unsigned& currentOffset, ContainerNode* root) const
+inline Element* LiveNodeListBase::traverseLiveNodeListForwardToOffset(unsigned offset, Element& currentElement, unsigned& currentOffset, ContainerNode* root) const
 {
     ASSERT(isNodeList(type()));
     ASSERT(type() != ChildNodeListType);
     if (type() == HTMLTagNodeListType)
         return traverseMatchingElementsForwardToOffset(static_cast<const HTMLTagNodeList*>(this), offset, currentElement, currentOffset, root);
     if (type() == ClassNodeListType)
         return traverseMatchingElementsForwardToOffset(static_cast<const ClassNodeList*>(this), offset, currentElement, currentOffset, root);
     return traverseMatchingElementsForwardToOffset(static_cast<const LiveNodeList*>(this), offset, currentElement, currentOffset, root);
 }
 
@@ skipping 100 matching lines @@
             }
         }
         ASSERT_NOT_REACHED();
         return 0;
     }
 
     unsigned offsetInArray = 0;
     if (type() == ChildNodeListType)
         currentItem = traverseChildNodeListForwardToOffset(offset, currentItem, currentOffset);
     else if (isNodeList(type()))
-        currentItem = traverseLiveNodeListForwardToOffset(offset, toElement(currentItem), currentOffset, root);
+        currentItem = traverseLiveNodeListForwardToOffset(offset, toElement(*currentItem), currentOffset, root);
     else
-        currentItem = static_cast<const HTMLCollection*>(this)->traverseForwardToOffset(offset, toElement(currentItem), currentOffset, offsetInArray, root);
+        currentItem = static_cast<const HTMLCollection*>(this)->traverseForwardToOffset(offset, toElement(*currentItem), currentOffset, offsetInArray, root);
 
     if (!currentItem) {
         // Did not find the item. On plus side, we now know the length.
         setLengthCache(currentOffset + 1);
         return 0;
     }
     setItemCache(currentItem, currentOffset, offsetInArray);
     return currentItem;
 }
 
@@ skipping 50 matching lines @@
 inline Element* HTMLCollection::traverseFirstElement(unsigned& offsetInArray, ContainerNode* root) const
 {
     if (overridesItemAfter())
         return virtualItemAfter(offsetInArray, 0);
     ASSERT(!offsetInArray);
     if (shouldOnlyIncludeDirectChildren())
         return firstMatchingChildElement(static_cast<const HTMLCollection*>(this), root);
     return firstMatchingElement(static_cast<const HTMLCollection*>(this), root);
 }
 
-inline Element* HTMLCollection::traverseNextElement(unsigned& offsetInArray, Element* previous, ContainerNode* root) const
+inline Element* HTMLCollection::traverseNextElement(unsigned& offsetInArray, Element& previous, ContainerNode* root) const
 {
     if (overridesItemAfter())
-        return virtualItemAfter(offsetInArray, previous);
+        return virtualItemAfter(offsetInArray, &previous);
     ASSERT(!offsetInArray);
     if (shouldOnlyIncludeDirectChildren())
-        return nextMatchingChildElement(this, previous, root);
+        return nextMatchingChildElement(this, &previous, root);
     return nextMatchingElement(this, previous, root);
 }
 
-inline Element* HTMLCollection::traverseForwardToOffset(unsigned offset, Element* currentElement, unsigned& currentOffset, unsigned& offsetInArray, ContainerNode* root) const
+inline Element* HTMLCollection::traverseForwardToOffset(unsigned offset, Element& currentElement, unsigned& currentOffset, unsigned& offsetInArray, ContainerNode* root) const
 {
     ASSERT(currentOffset < offset);
     if (overridesItemAfter()) {
         offsetInArray = m_cachedElementsArrayOffset;
-        while ((currentElement = virtualItemAfter(offsetInArray, currentElement))) {
+        Element* next = &currentElement;
+        while ((next = virtualItemAfter(offsetInArray, next))) {
             if (++currentOffset == offset)
-                return currentElement;
+                return next;
         }
         return 0;
     }
     if (shouldOnlyIncludeDirectChildren()) {
-        while ((currentElement = nextMatchingChildElement(this, currentElement, root))) {
+        Element* next = &currentElement;
+        while ((next = nextMatchingChildElement(this, next, root))) {
             if (++currentOffset == offset)
-                return currentElement;
+                return next;
         }
         return 0;
     }
     return traverseMatchingElementsForwardToOffset(this, offset, currentElement, currentOffset, root);
 }
 
 Node* HTMLCollection::namedItem(const AtomicString& name) const
 {
     // http://msdn.microsoft.com/workshop/author/dhtml/reference/methods/nameditem.asp
     // This method first searches for an object with a matching id
     // attribute. If a match is not found, the method then searches for an
     // object with a matching name attribute, but only on those elements
     // that are allowed a name attribute.
 
     ContainerNode* root = rootContainerNode();
     if (!root)
         return 0;
 
     unsigned arrayOffset = 0;
     unsigned i = 0;
-    for (Element* element = traverseFirstElement(arrayOffset, root); element; element = traverseNextElement(arrayOffset, element, root)) {
+    for (Element* element = traverseFirstElement(arrayOffset, root); element; element = traverseNextElement(arrayOffset, *element, root)) {
         if (checkForNameMatch(element, /* checkName */ false, name)) {
             setItemCache(element, i, arrayOffset);
             return element;
         }
         i++;
     }
 
     i = 0;
-    for (Element* element = traverseFirstElement(arrayOffset, root); element; element = traverseNextElement(arrayOffset, element, root)) {
+    for (Element* element = traverseFirstElement(arrayOffset, root); element; element = traverseNextElement(arrayOffset, *element, root)) {
         if (checkForNameMatch(element, /* checkName */ true, name)) {
             setItemCache(element, i, arrayOffset);
             return element;
         }
         i++;
     }
 
     return 0;
 }
 
 void HTMLCollection::updateNameCache() const
 {
     if (hasNameCache())
         return;
 
     ContainerNode* root = rootContainerNode();
     if (!root)
         return;
 
     unsigned arrayOffset = 0;
-    for (Element* element = traverseFirstElement(arrayOffset, root); element; element = traverseNextElement(arrayOffset, element, root)) {
+    for (Element* element = traverseFirstElement(arrayOffset, root); element; element = traverseNextElement(arrayOffset, *element, root)) {
         const AtomicString& idAttrVal = element->getIdAttribute();
         if (!idAttrVal.isEmpty())
             appendIdCache(idAttrVal, element);
         if (!element->isHTMLElement())
             continue;
         const AtomicString& nameAttrVal = element->getNameAttribute();
         if (!nameAttrVal.isEmpty() && idAttrVal != nameAttrVal && (type() != DocAll || nameShouldBeVisibleInDocumentAll(toHTMLElement(element))))
             appendNameCache(nameAttrVal, element);
     }
 
@@ skipping 40 matching lines @@
 
 void HTMLCollection::append(NodeCacheMap& map, const AtomicString& key, Element* element)
 {
     OwnPtr<Vector<Element*> >& vector = map.add(key.impl(), nullptr).iterator->value;
     if (!vector)
         vector = adoptPtr(new Vector<Element*>);
     vector->append(element);
 }
 
 } // namespace WebCore