| // 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. |
| |
| library deep_equals; |
| |
| /// Returns whether two objects are structurally equivalent. This considers NaN |
| /// values to be equivalent. It also handles self-referential structures. |
| bool deepEquals(obj1, obj2, [List parents1, List parents2]) { |
| if (identical(obj1, obj2)) return true; |
| if (parents1 == null) { |
| parents1 = []; |
| parents2 = []; |
| } |
| |
| // parents1 and parents2 are guaranteed to be the same size. |
| for (var i = 0; i < parents1.length; i++) { |
| var loop1 = identical(obj1, parents1[i]); |
| var loop2 = identical(obj2, parents2[i]); |
| // If both structures loop in the same place, they're equal at that point in |
| // the structure. If one loops and the other doesn't, they're not equal. |
| if (loop1 && loop2) return true; |
| if (loop1 || loop2) return false; |
| } |
| |
| parents1.add(obj1); |
| parents2.add(obj2); |
| try { |
| if (obj1 is List && obj2 is List) { |
| return _listEquals(obj1, obj2, parents1, parents2); |
| } else if (obj1 is Map && obj2 is Map) { |
| return _mapEquals(obj1, obj2, parents1, parents2); |
| } else if (obj1 is double && obj2 is double) { |
| return _doubleEquals(obj1, obj2); |
| } else { |
| return obj1 == obj2; |
| } |
| } finally { |
| parents1.removeLast(); |
| parents2.removeLast(); |
| } |
| } |
| |
| /// Returns whether [list1] and [list2] are structurally equal. |
| bool _listEquals(List list1, List list2, List parents1, List parents2) { |
| if (list1.length != list2.length) return false; |
| |
| for (var i = 0; i < list1.length; i++) { |
| if (!deepEquals(list1[i], list2[i], parents1, parents2)) return false; |
| } |
| |
| return true; |
| } |
| |
| /// Returns whether [map1] and [map2] are structurally equal. |
| bool _mapEquals(Map map1, Map map2, List parents1, List parents2) { |
| if (map1.length != map2.length) return false; |
| |
| for (var key in map1.keys) { |
| if (!map2.containsKey(key)) return false; |
| if (!deepEquals(map1[key], map2[key], parents1, parents2)) return false; |
| } |
| |
| return true; |
| } |
| |
| /// Returns whether two doubles are equivalent. This differs from `d1 == d2` in |
| /// that it considers NaN to be equal to itself. |
| bool _doubleEquals(double d1, double d2) { |
| if (d1.isNaN && d2.isNaN) return true; |
| return d1 == d2; |
| } |