Make sure the rootNode of a LiveNodeListBase is always a ContainerNode

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 142 matching lines @@
     case HTMLTagNodeListType:
     case RadioNodeListType:
     case RadioImgNodeListType:
     case LabelsNodeListType:
         break;
     }
     ASSERT_NOT_REACHED();
     return DoNotInvalidateOnAttributeChanges;
 }
 
-HTMLCollection::HTMLCollection(Node* ownerNode, CollectionType type, ItemAfterOverrideType itemAfterOverrideType)
+HTMLCollection::HTMLCollection(ContainerNode* ownerNode, CollectionType type, ItemAfterOverrideType itemAfterOverrideType)
     : LiveNodeListBase(ownerNode, rootTypeFromCollectionType(type), invalidationTypeExcludingIdAndNameAttributes(type),
         WebCore::shouldOnlyIncludeDirectChildren(type), type, itemAfterOverrideType)
     , m_isNameCacheValid(false)
 {
     ScriptWrappable::init(this);
 }
 
-PassRefPtr<HTMLCollection> HTMLCollection::create(Node* base, CollectionType type)
+PassRefPtr<HTMLCollection> HTMLCollection::create(ContainerNode* base, CollectionType type)
 {
     return adoptRef(new HTMLCollection(base, type, DoesNotOverrideItemAfter));
 }
 
 HTMLCollection::~HTMLCollection()
 {
     // HTMLNameCollection removes cache by itself.
     if (type() != WindowNamedItems && type() != DocumentNamedItems)
         ownerNode()->nodeLists()->removeCacheWithAtomicName(this, type());
 }
@@ skipping 237 matching lines @@
 
 // FIXME: It is silly that these functions are in HTMLCollection.cpp.
 Node* LiveNodeListBase::item(unsigned offset) const
 {
     if (cachedItem() && cachedItemOffset() == offset)
         return cachedItem();
 
     if (isLengthCacheValid() && cachedLength() <= offset)
         return 0;
 
-    ContainerNode* root = rootContainerNode();
-    if (!root) {
-        // FIMXE: In someTextNode.childNodes case the root is Text. We shouldn't even make a LiveNodeList for that.
-        setLengthCache(0);
-        return 0;
-    }
-
+    ContainerNode& root = rootNode();
     if (isLengthCacheValid() && !overridesItemAfter() && isLastItemCloserThanLastOrCachedItem(offset)) {
         Node* lastItem = itemBefore(0);
         ASSERT(lastItem);
         setItemCache(lastItem, cachedLength() - 1);
     } else if (!cachedItem() || isFirstItemCloserThanCachedItem(offset) || (overridesItemAfter() && offset < cachedItemOffset())) {
         Node* firstItem;
         if (isLiveNodeListType(type()))
-            firstItem = static_cast<const LiveNodeList*>(this)->traverseToFirstElement(*root);
+            firstItem = static_cast<const LiveNodeList*>(this)->traverseToFirstElement(root);
         else
-            firstItem = static_cast<const HTMLCollection*>(this)->traverseToFirstElement(*root);
+            firstItem = static_cast<const HTMLCollection*>(this)->traverseToFirstElement(root);
 
         if (!firstItem) {
             setLengthCache(0);
             return 0;
         }
         setItemCache(firstItem, 0);
         ASSERT(!cachedItemOffset());
     }
 
     if (cachedItemOffset() == offset)
         return cachedItem();
 
-    return itemBeforeOrAfterCachedItem(offset, *root);
+    return itemBeforeOrAfterCachedItem(offset, root);
 }
 
 inline Node* LiveNodeListBase::itemBeforeOrAfterCachedItem(unsigned offset, const ContainerNode& root) const
 {
     unsigned currentOffset = cachedItemOffset();
     Node* currentItem = cachedItem();
     ASSERT(currentItem);
     ASSERT(currentOffset != offset);
 
     if (offset < cachedItemOffset()) {
@@ skipping 116 matching lines @@
 }
 
 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;
-
+    ContainerNode& root = rootNode();
     unsigned i = 0;
-    for (Element* element = traverseToFirstElement(*root); element; element = traverseNextElement(*element, *root)) {
+    for (Element* element = traverseToFirstElement(root); element; element = traverseNextElement(*element, root)) {
         if (checkForNameMatch(*element, /* checkName */ false, name)) {
             setItemCache(element, i);
             return element;
         }
         i++;
     }
 
     i = 0;
-    for (Element* element = traverseToFirstElement(*root); element; element = traverseNextElement(*element, *root)) {
+    for (Element* element = traverseToFirstElement(root); element; element = traverseNextElement(*element, root)) {
         if (checkForNameMatch(*element, /* checkName */ true, name)) {
             setItemCache(element, i);
             return element;
         }
         i++;
     }
 
     return 0;
 }
 
 void HTMLCollection::updateNameCache() const
 {
     if (hasNameCache())
         return;
 
-    ContainerNode* root = rootContainerNode();
-    if (!root)
-        return;
-
-    for (Element* element = traverseToFirstElement(*root); element; element = traverseNextElement(*element, *root)) {
+    ContainerNode& root = rootNode();
+    for (Element* element = traverseToFirstElement(root); element; element = traverseNextElement(*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 20 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