| 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
|
| new file mode 100644
|
| index 0000000000000000000000000000000000000000..540813599c1f19c5d3b150749f6fb441bcd8a4dd
|
| --- /dev/null
|
| +++ b/mojo/public/dart/third_party/yaml/lib/src/equality.dart
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| @@ -0,0 +1,126 @@
|
| +// 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]);
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| + 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);
|
| +}
|
|
|