blob: deb4d658e2db31b6a812f4d1f466d378128b7ab4 [file] [log] [blame]
// Copyright 2015 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.
#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();
// The allocations caused by |AppendNode| below show up as hot in
// profiles. In order to mitigate this, we do an initial traversal to
// figure out how many nodes we plan on appending, reserve, and then
// append.
NodeChildrenIterator iterator(base_);
Node* child = iterator.First();
int pending_append_count = 0;
while (child) {
pending_append_count++;
child = iterator.Next();
}
ReserveForInternalCollection(pending_append_count);
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