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| 1 // Copyright (c) 2014, the Dart project authors. Please see the AUTHORS file | |
| 2 // for details. All rights reserved. Use of this source code is governed by a | |
| 3 // BSD-style license that can be found in the LICENSE file. | |
| 4 | |
| 5 library yaml.equality; | |
| 6 | |
| 7 import 'dart:collection'; | |
| 8 | |
| 9 import 'package:collection/collection.dart'; | |
| 10 | |
| 11 import 'yaml_node.dart'; | |
| 12 | |
| 13 /// Returns a [Map] that compares its keys based on [deepEquals]. | |
| 14 Map deepEqualsMap() => new HashMap(equals: deepEquals, hashCode: deepHashCode); | |
| 15 | |
| 16 /// Returns whether two objects are structurally equivalent. | |
| 17 /// | |
| 18 /// This considers `NaN` values to be equivalent, handles self-referential | |
| 19 /// structures, and considers [YamlScalar]s to be equal to their values. | |
| 20 bool deepEquals(obj1, obj2) => new _DeepEquals().equals(obj1, obj2); | |
| 21 | |
| 22 /// A class that provides access to the list of parent objects used for loop | |
| 23 /// detection. | |
| 24 class _DeepEquals { | |
| 25 final _parents1 = []; | |
| 26 final _parents2 = []; | |
| 27 | |
| 28 /// Returns whether [obj1] and [obj2] are structurally equivalent. | |
| 29 bool equals(obj1, obj2) { | |
| 30 if (obj1 is YamlScalar) obj1 = obj1.value; | |
| 31 if (obj2 is YamlScalar) obj2 = obj2.value; | |
| 32 | |
| 33 // _parents1 and _parents2 are guaranteed to be the same size. | |
| 34 for (var i = 0; i < _parents1.length; i++) { | |
| 35 var loop1 = identical(obj1, _parents1[i]); | |
| 36 var loop2 = identical(obj2, _parents2[i]); | |
| 37 // If both structures loop in the same place, they're equal at that point | |
| 38 // in the structure. If one loops and the other doesn't, they're not | |
| 39 // equal. | |
| 40 if (loop1 && loop2) return true; | |
| 41 if (loop1 || loop2) return false; | |
| 42 } | |
| 43 | |
| 44 _parents1.add(obj1); | |
| 45 _parents2.add(obj2); | |
| 46 try { | |
| 47 if (obj1 is List && obj2 is List) { | |
| 48 return _listEquals(obj1, obj2); | |
| 49 } else if (obj1 is Map && obj2 is Map) { | |
| 50 return _mapEquals(obj1, obj2); | |
| 51 } else if (obj1 is num && obj2 is num) { | |
| 52 return _numEquals(obj1, obj2); | |
| 53 } else { | |
| 54 return obj1 == obj2; | |
| 55 } | |
| 56 } finally { | |
| 57 _parents1.removeLast(); | |
| 58 _parents2.removeLast(); | |
| 59 } | |
| 60 } | |
| 61 | |
| 62 /// Returns whether [list1] and [list2] are structurally equal. | |
| 63 bool _listEquals(List list1, List list2) { | |
| 64 if (list1.length != list2.length) return false; | |
| 65 | |
| 66 for (var i = 0; i < list1.length; i++) { | |
| 67 if (!equals(list1[i], list2[i])) return false; | |
| 68 } | |
| 69 | |
| 70 return true; | |
| 71 } | |
| 72 | |
| 73 /// Returns whether [map1] and [map2] are structurally equal. | |
| 74 bool _mapEquals(Map map1, Map map2) { | |
| 75 if (map1.length != map2.length) return false; | |
| 76 | |
| 77 for (var key in map1.keys) { | |
| 78 if (!map2.containsKey(key)) return false; | |
| 79 if (!equals(map1[key], map2[key])) return false; | |
| 80 } | |
| 81 | |
| 82 return true; | |
| 83 } | |
| 84 | |
| 85 /// Returns whether two numbers are equivalent. | |
| 86 /// | |
| 87 /// This differs from `n1 == n2` in that it considers `NaN` to be equal to | |
| 88 /// itself. | |
| 89 bool _numEquals(num n1, num n2) { | |
| 90 if (n1.isNaN && n2.isNaN) return true; | |
| 91 return n1 == n2; | |
| 92 } | |
| 93 } | |
| 94 | |
| 95 /// Returns a hash code for [obj] such that structurally equivalent objects | |
| 96 /// will have the same hash code. | |
| 97 /// | |
| 98 /// This supports deep equality for maps and lists, including those with | |
| 99 /// self-referential structures, and returns the same hash code for | |
| 100 /// [YamlScalar]s and their values. | |
| 101 int deepHashCode(obj) { | |
| 102 var parents = []; | |
| 103 | |
| 104 _deepHashCode(value) { | |
| 105 if (parents.any((parent) => identical(parent, value))) return -1; | |
| 106 | |
| 107 parents.add(value); | |
| 108 try { | |
| 109 if (value is Map) { | |
| 110 var equality = const UnorderedIterableEquality(); | |
| 111 return equality.hash(value.keys.map(_deepHashCode)) ^ | |
| 112 equality.hash(value.values.map(_deepHashCode)); | |
| 113 } else if (value is Iterable) { | |
| 114 return const IterableEquality().hash(value.map(deepHashCode)); | |
| 115 } else if (value is YamlScalar) { | |
| 116 return value.value.hashCode; | |
| 117 } else { | |
| 118 return value.hashCode; | |
| 119 } | |
| 120 } finally { | |
| 121 parents.removeLast(); | |
| 122 } | |
| 123 } | |
| 124 | |
| 125 return _deepHashCode(obj); | |
| 126 } | |
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Chromium Code Reviews
Issue 1400473008:
Roll Observatory packages and add a roll script (Closed)
Base URL: git@github.com:dart-lang/observatory_pub_packages.git@master