/*
 * Copyright 2015 Google Inc. 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.
 */

#include "cobalt/dom/node_list_live.h"

#include "cobalt/dom/node.h"
#include "cobalt/dom/node_children_iterator.h"

namespace cobalt {
namespace dom {

// static
scoped_refptr<NodeListLive> NodeListLive::CreateWithChildren(
    const scoped_refptr<const Node>& base) {
  DCHECK(base.get());
  return new NodeListLive(base);
}

unsigned int NodeListLive::length() {
  MaybeRefreshCollection();
  return NodeList::length();
}

scoped_refptr<Node> NodeListLive::Item(unsigned int item) {
  MaybeRefreshCollection();
  return NodeList::Item(item);
}

void NodeListLive::MaybeRefreshCollection() {
  if (base_node_generation_ != base_->node_generation()) {
    Clear();

    NodeChildrenIterator iterator(base_);
    Node* child = iterator.First();
    while (child) {
      AppendNode(child);
      child = iterator.Next();
    }
    base_node_generation_ = base_->node_generation();
  }
}

NodeListLive::NodeListLive(const scoped_refptr<const Node>& base)
    : base_(base), base_node_generation_(Node::kInvalidNodeGeneration) {}

}  // namespace dom
}  // namespace cobalt