Introduce typed Node/Element iterators for range-based for loops of C++11.

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, 2013 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 16 matching lines @@
 #define ElementTraversal_h
 
 #include "core/dom/Element.h"
 #include "core/dom/NodeTraversal.h"
 
 namespace blink {
 
 template <class ElementType>
 class Traversal {
 public:
+    using TraversalNodeType = ElementType;
     // First or last ElementType child of the node.
     static ElementType* firstChild(const ContainerNode& current) { return firstChildTemplate(current); }
     static ElementType* firstChild(const Node& current) { return firstChildTemplate(current); }
     template <class MatchFunc>
     static ElementType* firstChild(const ContainerNode&, MatchFunc);
     static ElementType* lastChild(const ContainerNode& current) { return lastChildTemplate(current); }
     static ElementType* lastChild(const Node& current) { return lastChildTemplate(current); }
     template <class MatchFunc>
     static ElementType* lastChild(const ContainerNode&, MatchFunc);
 
@@ skipping 40 matching lines @@
     static ElementType* pseudoAwarePreviousSibling(const Node&);
 
     // Previous / Next sibling.
     static ElementType* previousSibling(const Node&);
     template <class MatchFunc>
     static ElementType* previousSibling(const Node&, MatchFunc);
     static ElementType* nextSibling(const Node&);
     template <class MatchFunc>
     static ElementType* nextSibling(const Node&, MatchFunc);
 
+    static TraversalRange<TraversalChildrenIterator<Traversal<ElementType>>> childrenOf(const Node&);
+    static TraversalRange<TraversalDescendantIterator<Traversal<ElementType>>> descendantsOf(const Node&);
+    static TraversalRange<TraversalInclusiveDescendantIterator<Traversal<ElementType>>> inclusiveDescendantsOf(const ElementType&);
+    static TraversalRange<TraversalNextIterator<Traversal<ElementType>>> fromNext(const Node&);
+
 private:
     template <class NodeType>
     static ElementType* firstChildTemplate(NodeType&);
     template <class NodeType>
     static ElementType* lastChildTemplate(NodeType&);
     template <class NodeType>
     static ElementType* firstAncestorOrSelfTemplate(NodeType&);
     template <class NodeType>
     static ElementType* firstWithinTemplate(NodeType&);
     template <class NodeType>
     static ElementType* lastWithinTemplate(NodeType&);
     template <class NodeType>
     static ElementType* nextTemplate(NodeType&);
     template <class NodeType>
     static ElementType* nextTemplate(NodeType&, const Node* stayWithin);
 };
 
 typedef Traversal<Element> ElementTraversal;
 
+template <class ElementType>
+inline TraversalRange<TraversalChildrenIterator<Traversal<ElementType>>> Traversal<ElementType>::childrenOf(const Node& start)
+{
+    return TraversalRange<TraversalChildrenIterator<Traversal<ElementType>>>(start);
+};
+
+template <class ElementType>
+inline TraversalRange<TraversalDescendantIterator<Traversal<ElementType>>> Traversal<ElementType>::descendantsOf(const Node& root)
+{
+    return TraversalRange<TraversalDescendantIterator<Traversal<ElementType>>>(root);
+};
+
+template <class ElementType>
+inline TraversalRange<TraversalInclusiveDescendantIterator<Traversal<ElementType>>> Traversal<ElementType>::inclusiveDescendantsOf(const ElementType& root)
+{
+    return TraversalRange<TraversalInclusiveDescendantIterator<Traversal<ElementType>>>(root);
+};
+
+template <class ElementType>
+inline TraversalRange<TraversalNextIterator<Traversal<ElementType>>> Traversal<ElementType>::fromNext(const Node& start)

[dglazkov, 2014/10/21 16:03:11]

This name had stumped me a little bit. What does it mean? :)

[hayato, 2014/10/22 05:15:18]

NodeTraversal::startsFromNext might be better?

Another idea is to remove `fromNext` and let clients use NodeTraversal::from()
instead of NodeTraversal::fromNext().

The means we would replace:

  for (Node& node : NodeTraversal::fromNext(start))

with

 for (Node& node : NodeTraversal::from(NodeTraversal::next(start)))

WDYT?

I am also feeling that NodeTraversal::from(const Node&) is not a good name.
NodeTraversal::startsFrom(const Node*) might be better?

+{
+    return TraversalRange<TraversalNextIterator<Traversal<ElementType>>>(start);
+};
+
 // Specialized for pure Element to exploit the fact that Elements parent is always either another Element or the root.
 template <>
 template <class NodeType>
 inline Element* Traversal<Element>::firstWithinTemplate(NodeType& current)
 {
     return firstChildTemplate(current);
 }
 
 template <>
 template <class NodeType>
@@ skipping 260 matching lines @@
 {
     ElementType* element = Traversal<ElementType>::nextSibling(current);
     while (element && !isMatch(*element))
         element = Traversal<ElementType>::nextSibling(*element);
     return element;
 }
 
 } // namespace blink
 
 #endif