sdk/lib/html/src/FilteredElementList.dart

// Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

part of html;

class FilteredElementList implements List {
  final Node _node;
  final List<Node> _childNodes;

  FilteredElementList(Node node): _childNodes = node.nodes, _node = node;

  // We can't memoize this, since it's possible that children will be messed
  // with externally to this class.
  //
  // TODO(nweiz): Do we really need to copy the list to make the types work out?
  List<Element> get _filtered =>
    new List.from(_childNodes.filter((n) => n is Element));

  void forEach(void f(Element element)) {
    _filtered.forEach(f);
  }

  void operator []=(int index, Element value) {
    this[index].replaceWith(value);
  }

  void set length(int newLength) {
    final len = this.length;
    if (newLength >= len) {
      return;
    } else if (newLength < 0) {
      throw new ArgumentError("Invalid list length");
    }

    removeRange(newLength - 1, len - newLength);
  }

  void add(Element value) {
    _childNodes.add(value);
  }

  void addAll(Collection<Element> collection) {
    collection.forEach(add);
  }

  void addLast(Element value) {
    add(value);
  }

  bool contains(Element element) {
    return element is Element && _childNodes.contains(element);
  }

  void sort([Comparator<Element> compare = Comparable.compare]) {
    throw new UnsupportedError('TODO(jacobr): should we impl?');
  }

  void setRange(int start, int rangeLength, List from, [int startFrom = 0]) {
    throw new UnimplementedError();
  }

  void removeRange(int start, int rangeLength) {
    _filtered.getRange(start, rangeLength).forEach((el) => el.remove());
  }

  void insertRange(int start, int rangeLength, [initialValue = null]) {
    throw new UnimplementedError();
  }

  void clear() {
    // Currently, ElementList#clear clears even non-element nodes, so we follow
    // that behavior.
    _childNodes.clear();
  }

  Element removeLast() {
    final result = this.last;
    if (result != null) {
      result.remove();
    }
    return result;
  }

  Collection map(f(Element element)) => _filtered.map(f);
  Collection<Element> filter(bool f(Element element)) => _filtered.filter(f);
  bool every(bool f(Element element)) => _filtered.every(f);
  bool some(bool f(Element element)) => _filtered.some(f);
  bool get isEmpty => _filtered.isEmpty;
  int get length => _filtered.length;
  Element operator [](int index) => _filtered[index];
  Iterator<Element> iterator() => _filtered.iterator();
  List<Element> getRange(int start, int rangeLength) =>
    _filtered.getRange(start, rangeLength);
  int indexOf(Element element, [int start = 0]) =>
    _filtered.indexOf(element, start);

  int lastIndexOf(Element element, [int start = null]) {
    if (start == null) start = length - 1;
    return _filtered.lastIndexOf(element, start);
  }

  Element get first => _filtered.first;

  Element get last => _filtered.last;
}