Index: mojo/public/dart/third_party/yaml/lib/src/equality.dart |
diff --git a/mojo/public/dart/third_party/yaml/lib/src/equality.dart b/mojo/public/dart/third_party/yaml/lib/src/equality.dart |
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index 0000000000000000000000000000000000000000..540813599c1f19c5d3b150749f6fb441bcd8a4dd |
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+++ b/mojo/public/dart/third_party/yaml/lib/src/equality.dart |
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+// 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. |
+ |
+library yaml.equality; |
+ |
+import 'dart:collection'; |
+ |
+import 'package:collection/collection.dart'; |
+ |
+import 'yaml_node.dart'; |
+ |
+/// Returns a [Map] that compares its keys based on [deepEquals]. |
+Map deepEqualsMap() => new HashMap(equals: deepEquals, hashCode: deepHashCode); |
+ |
+/// Returns whether two objects are structurally equivalent. |
+/// |
+/// This considers `NaN` values to be equivalent, handles self-referential |
+/// structures, and considers [YamlScalar]s to be equal to their values. |
+bool deepEquals(obj1, obj2) => new _DeepEquals().equals(obj1, obj2); |
+ |
+/// A class that provides access to the list of parent objects used for loop |
+/// detection. |
+class _DeepEquals { |
+ final _parents1 = []; |
+ final _parents2 = []; |
+ |
+ /// Returns whether [obj1] and [obj2] are structurally equivalent. |
+ bool equals(obj1, obj2) { |
+ if (obj1 is YamlScalar) obj1 = obj1.value; |
+ if (obj2 is YamlScalar) obj2 = obj2.value; |
+ |
+ // _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); |
+ } else if (obj1 is Map && obj2 is Map) { |
+ return _mapEquals(obj1, obj2); |
+ } else if (obj1 is num && obj2 is num) { |
+ return _numEquals(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) { |
+ if (list1.length != list2.length) return false; |
+ |
+ for (var i = 0; i < list1.length; i++) { |
+ if (!equals(list1[i], list2[i])) return false; |
+ } |
+ |
+ return true; |
+ } |
+ |
+ /// Returns whether [map1] and [map2] are structurally equal. |
+ bool _mapEquals(Map map1, Map map2) { |
+ if (map1.length != map2.length) return false; |
+ |
+ for (var key in map1.keys) { |
+ if (!map2.containsKey(key)) return false; |
+ if (!equals(map1[key], map2[key])) return false; |
+ } |
+ |
+ return true; |
+ } |
+ |
+ /// Returns whether two numbers are equivalent. |
+ /// |
+ /// This differs from `n1 == n2` in that it considers `NaN` to be equal to |
+ /// itself. |
+ bool _numEquals(num n1, num n2) { |
+ if (n1.isNaN && n2.isNaN) return true; |
+ return n1 == n2; |
+ } |
+} |
+ |
+/// Returns a hash code for [obj] such that structurally equivalent objects |
+/// will have the same hash code. |
+/// |
+/// This supports deep equality for maps and lists, including those with |
+/// self-referential structures, and returns the same hash code for |
+/// [YamlScalar]s and their values. |
+int deepHashCode(obj) { |
+ var parents = []; |
+ |
+ _deepHashCode(value) { |
+ if (parents.any((parent) => identical(parent, value))) return -1; |
+ |
+ parents.add(value); |
+ try { |
+ if (value is Map) { |
+ var equality = const UnorderedIterableEquality(); |
+ return equality.hash(value.keys.map(_deepHashCode)) ^ |
+ equality.hash(value.values.map(_deepHashCode)); |
+ } else if (value is Iterable) { |
+ return const IterableEquality().hash(value.map(deepHashCode)); |
+ } else if (value is YamlScalar) { |
+ return value.value.hashCode; |
+ } else { |
+ return value.hashCode; |
+ } |
+ } finally { |
+ parents.removeLast(); |
+ } |
+ } |
+ |
+ return _deepHashCode(obj); |
+} |