dart-sdk/runtime/lib/array_patch.dart

// Copyright (c) 2012, 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 "core_patch.dart";

@patch
class List<E> {
  @patch
  factory List([int length]) native "List_new";

  @patch
  factory List.filled(int length, E fill, {bool growable: false}) {
    // All error handling on the length parameter is done at the implementation
    // of new _List.
    var result = growable ? new _GrowableList<E>(length) : new _List<E>(length);
    if (fill != null) {
      for (int i = 0; i < length; i++) {
        result[i] = fill;
      }
    }
    return result;
  }

  @patch
  factory List.from(Iterable elements, {bool growable: true}) {
    if (elements is EfficientLengthIterable<E>) {
      int length = elements.length;
      var list = growable ? new _GrowableList<E>(length) : new _List<E>(length);
      if (length > 0) {
        // Avoid creating iterator unless necessary.
        int i = 0;
        for (var element in elements) {
          list[i++] = element;
        }
      }
      return list;
    }
    // If elements is an Iterable<E>, we won't need a type-test for each
    // element. In the "common case" that elements is an Iterable<E>, this
    // replaces a type-test on every element with a single type-test before
    // starting the loop.
    if (elements is Iterable<E>) {
      List<E> list = new _GrowableList<E>(0);
      for (E e in elements) {
        list.add(e);
      }
      if (growable) return list;
      return makeListFixedLength(list);
    } else {
      List<E> list = new _GrowableList<E>(0);
      for (E e in elements) {
        list.add(e);
      }
      if (growable) return list;
      return makeListFixedLength(list);
    }
  }

  @patch
  factory List.unmodifiable(Iterable elements) {
    final result = new List<E>.from(elements, growable: false);
    return makeFixedListUnmodifiable(result);
  }

  // Factory constructing a mutable List from a parser generated List literal.
  // [elements] contains elements that are already type checked.
  @pragma("vm:entry-point", "call")
  factory List._fromLiteral(List elements) {
    if (elements.isEmpty) {
      return new _GrowableList<E>(0);
    }
    var result = new _GrowableList<E>._withData(elements);
    result._setLength(elements.length);
    return result;
  }
}