| // 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_ |