mcs/class/referencesource/System.Activities.Presentation/Microsoft.Tools.Common/Microsoft/Activities/Presentation/Xaml/ObjectReferenceEqualityComparer.cs

   1 //----------------------------------------------------------------
   2 // <copyright company="Microsoft Corporation">
   3 //     Copyright (c) Microsoft Corporation.  All rights reserved.
   4 // </copyright>
   5 //----------------------------------------------------------------
   6
   7 namespace Microsoft.Activities.Presentation.Xaml
   8 {
   9     using System.Collections.Generic;
  10     using System.Runtime.CompilerServices;
  11
  12     internal sealed class ObjectReferenceEqualityComparer<T> : IEqualityComparer<T> where T : class
  13     {
  14         private static ObjectReferenceEqualityComparer<T> defaultComparer;
  15
  16         private ObjectReferenceEqualityComparer()
  17         {
  18         }
  19
  20         public static ObjectReferenceEqualityComparer<T> Default
  21         {
  22             get
  23             {
  24                 if (defaultComparer == null)
  25                 {
  26                     defaultComparer = new ObjectReferenceEqualityComparer<T>();
  27                 }
  28
  29                 return defaultComparer;
  30             }
  31         }
  32
  33         public bool Equals(T x, T y)
  34         {
  35             return object.ReferenceEquals(x, y);
  36         }
  37
  38         public int GetHashCode(T obj)
  39         {
  40             return RuntimeHelpers.GetHashCode(obj);
  41         }
  42     }
  43 }