Add template parameter to ElementTraversal to iterate over Elements of a specific type

Source/core/dom/ElementTraversal.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2014 Samsung Electronics. 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
@@ skipping 13 matching lines @@
  */
 
 #ifndef ElementTraversal_h
 #define ElementTraversal_h
 
 #include "core/dom/Element.h"
 #include "core/dom/NodeTraversal.h"
 
 namespace WebCore {
 
-class ElementTraversal {
+template <class ElementType>
+class Traversal {
 public:
     // First / Last element child of the node.
-    static Element* firstWithin(const ContainerNode& current) { return firstElementWithinTemplate(current); }
-    static Element* firstWithin(const Node& current) { return firstElementWithinTemplate(current); }
-    static Element* lastWithin(const ContainerNode& current) { return lastWithinTemplate(current); }
-    static Element* lastWithin(const Node& current) { return lastWithinTemplate(current); }
+    static ElementType* firstWithin(const ContainerNode& current) { return firstElementWithinTemplate(current); }
+    static ElementType* firstWithin(const Node& current) { return firstElementWithinTemplate(current); }
+    static ElementType* lastWithin(const ContainerNode& current) { return lastWithinTemplate(current); }
+    static ElementType* lastWithin(const Node& current) { return lastWithinTemplate(current); }
 
     // Pre-order traversal skipping non-element nodes.
-    static Element* next(const ContainerNode& current) { return traverseNextElementTemplate(current); }
-    static Element* next(const Node& current) { return traverseNextElementTemplate(current); }
-    static Element* next(const ContainerNode& current, const Node* stayWithin) { return traverseNextElementTemplate(current, stayWithin); }
-    static Element* next(const Node& current, const Node* stayWithin) { return traverseNextElementTemplate(current, stayWithin); }
+    static ElementType* next(const ContainerNode& current) { return traverseNextElementTemplate(current); }
+    static ElementType* next(const Node& current) { return traverseNextElementTemplate(current); }
+    static ElementType* next(const ContainerNode& current, const Node* stayWithin) { return traverseNextElementTemplate(current, stayWithin); }
+    static ElementType* next(const Node& current, const Node* stayWithin) { return traverseNextElementTemplate(current, stayWithin); }
 
     // Like next, but skips children.
-    static Element* nextSkippingChildren(const ContainerNode& current) { return traverseNextElementSkippingChildrenTemplate(current); }
-    static Element* nextSkippingChildren(const Node& current) { return traverseNextElementSkippingChildrenTemplate(current); }
-    static Element* nextSkippingChildren(const ContainerNode& current, const Node* stayWithin) { return traverseNextElementSkippingChildrenTemplate(current, stayWithin); }
-    static Element* nextSkippingChildren(const Node& current, const Node* stayWithin) { return traverseNextElementSkippingChildrenTemplate(current, stayWithin); }
+    static ElementType* nextSkippingChildren(const ContainerNode& current) { return traverseNextElementSkippingChildrenTemplate(current); }
+    static ElementType* nextSkippingChildren(const Node& current) { return traverseNextElementSkippingChildrenTemplate(current); }
+    static ElementType* nextSkippingChildren(const ContainerNode& current, const Node* stayWithin) { return traverseNextElementSkippingChildrenTemplate(current, stayWithin); }
+    static ElementType* nextSkippingChildren(const Node& current, const Node* stayWithin) { return traverseNextElementSkippingChildrenTemplate(current, stayWithin); }
 
     // Pre-order traversal including the pseudo-elements.
-    static Element* previousIncludingPseudo(const Node&, const Node* stayWithin = 0);
-    static Element* nextIncludingPseudo(const Node&, const Node* stayWithin = 0);
-    static Element* nextIncludingPseudoSkippingChildren(const Node&, const Node* stayWithin = 0);
+    static ElementType* previousIncludingPseudo(const Node&, const Node* stayWithin = 0);
+    static ElementType* nextIncludingPseudo(const Node&, const Node* stayWithin = 0);
+    static ElementType* nextIncludingPseudoSkippingChildren(const Node&, const Node* stayWithin = 0);
 
     // Utility function to traverse only the element and pseudo-element siblings of a node.
-    static Element* pseudoAwarePreviousSibling(const Node&);
+    static ElementType* pseudoAwarePreviousSibling(const Node&);
 
     // Previous / Next sibling.
-    static Element* previousSibling(const Node&);
-    static Element* nextSibling(const Node&);
+    static ElementType* previousSibling(const Node&);
+    static ElementType* nextSibling(const Node&);
 
 private:
     template <class NodeType>
-    static Element* firstElementWithinTemplate(NodeType&);
+    static ElementType* firstElementWithinTemplate(NodeType&);
     template <class NodeType>
-    static Element* lastWithinTemplate(NodeType&);
+    static ElementType* lastWithinTemplate(NodeType&);
     template <class NodeType>
-    static Element* traverseNextElementTemplate(NodeType&);
+    static ElementType* traverseNextElementTemplate(NodeType&);
     template <class NodeType>
-    static Element* traverseNextElementTemplate(NodeType&, const Node* stayWithin);
+    static ElementType* traverseNextElementTemplate(NodeType&, const Node* stayWithin);
     template <class NodeType>
-    static Element* traverseNextElementSkippingChildrenTemplate(NodeType&);
+    static ElementType* traverseNextElementSkippingChildrenTemplate(NodeType&);
     template <class NodeType>
-    static Element* traverseNextElementSkippingChildrenTemplate(NodeType&, const Node* stayWithin);
+    static ElementType* traverseNextElementSkippingChildrenTemplate(NodeType&, const Node* stayWithin);
 };
 
+typedef Traversal<Element> ElementTraversal;
+
+template <class ElementType>
 template <class NodeType>
-inline Element* ElementTraversal::firstElementWithinTemplate(NodeType& current)
+inline ElementType* Traversal<ElementType>::firstElementWithinTemplate(NodeType& current)
 {
     // Except for the root containers, only elements can have element children.
     Node* node = current.firstChild();
-    while (node && !node->isElementNode())
+    while (node && !isElementOfType<ElementType>(*node))
         node = node->nextSibling();
-    return toElement(node);
+    return toElement<ElementType>(node);
 }
 
+template <class ElementType>
 template <class NodeType>
-inline Element* ElementTraversal::lastWithinTemplate(NodeType& current)
+inline ElementType* Traversal<ElementType>::lastWithinTemplate(NodeType& current)
 {
     Node* node = current.lastChild();
-    while (node && !node->isElementNode())
+    while (node && !isElementOfType<ElementType>(*node))
         node = node->previousSibling();
-    return toElement(node);
+    return toElement<ElementType>(node);
 }
 
+template <class ElementType>

[esprehn, 2014/02/26 20:17:49]

Why stack two template<> decls instead of doing template<class ElementType,
class NodeType> ?

[Inactive, 2014/02/26 20:24:25]

This does not build (just double-checked). one template is for the class, and
the other is for the method. It is a templated method/function inside a
templated class.

[Inactive, 2014/02/26 20:29:13]

FYI, since I googled it as well:
http://stackoverflow.com/questions/8640390/c-template-function-inside-templat...

 template <class NodeType>
-inline Element* ElementTraversal::traverseNextElementTemplate(NodeType& current)
+inline ElementType* Traversal<ElementType>::traverseNextElementTemplate(NodeType& current)
 {
     Node* node = NodeTraversal::next(current);
-    while (node && !node->isElementNode())
+    while (node && !isElementOfType<ElementType>(*node))
         node = NodeTraversal::nextSkippingChildren(*node);
-    return toElement(node);
+    return toElement<ElementType>(node);
 }
 
+template <class ElementType>
 template <class NodeType>
-inline Element* ElementTraversal::traverseNextElementTemplate(NodeType& current, const Node* stayWithin)
+inline ElementType* Traversal<ElementType>::traverseNextElementTemplate(NodeType& current, const Node* stayWithin)
 {
     Node* node = NodeTraversal::next(current, stayWithin);
-    while (node && !node->isElementNode())
+    while (node && !isElementOfType<ElementType>(*node))
         node = NodeTraversal::nextSkippingChildren(*node, stayWithin);
-    return toElement(node);
+    return toElement<ElementType>(node);
 }
 
+template <class ElementType>
 template <class NodeType>
-inline Element* ElementTraversal::traverseNextElementSkippingChildrenTemplate(NodeType& current)
+inline ElementType* Traversal<ElementType>::traverseNextElementSkippingChildrenTemplate(NodeType& current)
 {
     Node* node = NodeTraversal::nextSkippingChildren(current);
-    while (node && !node->isElementNode())
+    while (node && !isElementOfType<ElementType>(*node))
         node = NodeTraversal::nextSkippingChildren(*node);
-    return toElement(node);
+    return toElement<ElementType>(node);
 }
 
+template <class ElementType>
 template <class NodeType>
-inline Element* ElementTraversal::traverseNextElementSkippingChildrenTemplate(NodeType& current, const Node* stayWithin)
+inline ElementType* Traversal<ElementType>::traverseNextElementSkippingChildrenTemplate(NodeType& current, const Node* stayWithin)
 {
     Node* node = NodeTraversal::nextSkippingChildren(current, stayWithin);
-    while (node && !node->isElementNode())
+    while (node && !isElementOfType<ElementType>(*node))
         node = NodeTraversal::nextSkippingChildren(*node, stayWithin);
-    return toElement(node);
+    return toElement<ElementType>(node);
 }
 
-inline Element* ElementTraversal::previousIncludingPseudo(const Node& current, const Node* stayWithin)
+template <class ElementType>
+inline ElementType* Traversal<ElementType>::previousIncludingPseudo(const Node& current, const Node* stayWithin)
 {
     Node* node = NodeTraversal::previousIncludingPseudo(current, stayWithin);
-    while (node && !node->isElementNode())
+    while (node && !isElementOfType<ElementType>(*node))
         node = NodeTraversal::previousIncludingPseudo(*node, stayWithin);
-    return toElement(node);
+    return toElement<ElementType>(node);
 }
 
-inline Element* ElementTraversal::nextIncludingPseudo(const Node& current, const Node* stayWithin)
+template <class ElementType>
+inline ElementType* Traversal<ElementType>::nextIncludingPseudo(const Node& current, const Node* stayWithin)
 {
     Node* node = NodeTraversal::nextIncludingPseudo(current, stayWithin);
-    while (node && !node->isElementNode())
+    while (node && !isElementOfType<ElementType>(*node))
         node = NodeTraversal::nextIncludingPseudo(*node, stayWithin);
-    return toElement(node);
+    return toElement<ElementType>(node);
 }
 
-inline Element* ElementTraversal::nextIncludingPseudoSkippingChildren(const Node& current, const Node* stayWithin)
+template <class ElementType>
+inline ElementType* Traversal<ElementType>::nextIncludingPseudoSkippingChildren(const Node& current, const Node* stayWithin)
 {
     Node* node = NodeTraversal::nextIncludingPseudoSkippingChildren(current, stayWithin);
-    while (node && !node->isElementNode())
+    while (node && !isElementOfType<ElementType>(*node))
         node = NodeTraversal::nextIncludingPseudoSkippingChildren(*node, stayWithin);
-    return toElement(node);
+    return toElement<ElementType>(node);
 }
 
-inline Element* ElementTraversal::pseudoAwarePreviousSibling(const Node& current)
+template <class ElementType>
+inline ElementType* Traversal<ElementType>::pseudoAwarePreviousSibling(const Node& current)
 {
     Node* node = current.pseudoAwarePreviousSibling();
-    while (node && !node->isElementNode())
+    while (node && !isElementOfType<ElementType>(*node))
         node = node->pseudoAwarePreviousSibling();
-    return toElement(node);
+    return toElement<ElementType>(node);
 }
 
-inline Element* ElementTraversal::previousSibling(const Node& current)
+template <class ElementType>
+inline ElementType* Traversal<ElementType>::previousSibling(const Node& current)
 {
     Node* node = current.previousSibling();
-    while (node && !node->isElementNode())
+    while (node && !isElementOfType<ElementType>(*node))
         node = node->previousSibling();
-    return toElement(node);
+    return toElement<ElementType>(node);
 }
 
-inline Element* ElementTraversal::nextSibling(const Node& current)
+template <class ElementType>
+inline ElementType* Traversal<ElementType>::nextSibling(const Node& current)
 {
     Node* node = current.nextSibling();
-    while (node && !node->isElementNode())
+    while (node && !isElementOfType<ElementType>(*node))
         node = node->nextSibling();
-    return toElement(node);
+    return toElement<ElementType>(node);
 }
 
 } // namespace WebCore
 
 #endif