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// Copyright 2014 The Cobalt Authors. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#ifndef COBALT_DOM_NODE_DESCENDANTS_ITERATOR_H_
#define COBALT_DOM_NODE_DESCENDANTS_ITERATOR_H_
#include "cobalt/dom/node.h"
namespace cobalt {
namespace dom {
// Iterates over all descendants of the given node (excluding the node itself).
// The iterator uses depth-first pre-order traversal to visit the descendants.
class NodeDescendantsIterator {
public:
explicit NodeDescendantsIterator(const scoped_refptr<const Node>& base)
: base_(base), current_(NULL) {}
Node* First() {
current_ = base_->first_child();
return current_;
}
Node* Next() {
if (!current_) {
return NULL;
}
if (current_->first_child()) {
// Walk down and use the first child.
current_ = current_->first_child();
} else {
// Walk towards the next sibling if one exists.
// If one doesn't exist, walk up and look for a node (that is not a root)
// with a sibling and continue the iteration from there.
while (!current_->next_sibling()) {
current_ = current_->parent_node();
if (current_ == base_) {
current_ = NULL;
return current_;
}
}
current_ = current_->next_sibling();
}
return current_;
}
private:
scoped_refptr<const Node> base_;
// Scoped pointer is not used for optimization reasons.
Node* current_;
};
} // namespace dom
} // namespace cobalt
#endif // COBALT_DOM_NODE_DESCENDANTS_ITERATOR_H_