| // Copyright (c) 2014, 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. |
| |
| import 'dart:collection'; |
| |
| import 'package:yaml/yaml.dart'; |
| |
| /// Test if the given [value] is `false` or the string "false" |
| /// (case-insensitive). |
| bool isFalse(Object value) => |
| value is bool ? !value : toLowerCase(value) == 'false'; |
| |
| /// Test if the given [value] is `true` or the string "true" (case-insensitive). |
| bool isTrue(Object value) => |
| value is bool ? value : toLowerCase(value) == 'true'; |
| |
| /// Safely convert the given [value] to a bool value, or return `null` if the |
| /// value could not be converted. |
| bool? toBool(Object value) { |
| if (value is YamlScalar) { |
| value = value.value; |
| } |
| if (value is bool) { |
| return value; |
| } |
| var string = toLowerCase(value); |
| if (string == 'true') { |
| return true; |
| } |
| if (string == 'false') { |
| return false; |
| } |
| return null; |
| } |
| |
| /// Safely convert this [value] to lower case, returning `null` if [value] is |
| /// null. |
| String? toLowerCase(Object? value) => value?.toString().toLowerCase(); |
| |
| /// Safely convert this [value] to upper case, returning `null` if [value] is |
| /// null. |
| String? toUpperCase(Object? value) => value?.toString().toUpperCase(); |
| |
| /// A simple limited queue. |
| class LimitedQueue<E> extends ListQueue<E> { |
| final int limit; |
| |
| /// Create a queue with [limit] items. |
| LimitedQueue(this.limit); |
| |
| @override |
| void add(E value) { |
| super.add(value); |
| while (length > limit) { |
| remove(first); |
| } |
| } |
| } |