mcs/class/corlib/System.Threading/CancellationToken.cs

   1 //
   2 // CancellationToken.cs
   3 //
   4 // Authors:
   5 //       Jérémie "Garuma" Laval <jeremie.laval@gmail.com>
   6 //       Marek Safar (marek.safar@gmail.com)
   7 //
   8 // Copyright (c) 2009 Jérémie "Garuma" Laval
   9 // Copyright 2011 Xamarin, Inc (http://www.xamarin.com)
  10 //
  11 // Permission is hereby granted, free of charge, to any person obtaining a copy
  12 // of this software and associated documentation files (the "Software"), to deal
  13 // in the Software without restriction, including without limitation the rights
  14 // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  15 // copies of the Software, and to permit persons to whom the Software is
  16 // furnished to do so, subject to the following conditions:
  17 //
  18 // The above copyright notice and this permission notice shall be included in
  19 // all copies or substantial portions of the Software.
  20 //
  21 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  22 // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  23 // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  24 // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  25 // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  26 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  27 // THE SOFTWARE.
  28
  29 #if NET_4_0
  30
  31 using System;
  32 using System.Threading;
  33 using System.Diagnostics;
  34
  35 namespace System.Threading
  36 {
  37         [DebuggerDisplay ("IsCancellationRequested = {IsCancellationRequested}")]
  38         public struct CancellationToken
  39         {
  40                 readonly CancellationTokenSource source;
  41
  42                 public CancellationToken (bool canceled)
  43                         : this (canceled ? CancellationTokenSource.CanceledSource : null)
  44                 {
  45                 }
  46
  47                 internal CancellationToken (CancellationTokenSource source)
  48                 {
  49                         this.source = source;
  50                 }
  51
  52                 public static CancellationToken None {
  53                         get {
  54                                 // simply return new struct value, it's the fastest option
  55                                 // and we don't have to bother with reseting source
  56                                 return new CancellationToken ();
  57                         }
  58                 }
  59
  60                 public CancellationTokenRegistration Register (Action callback)
  61                 {
  62                         return Register (callback, false);
  63                 }
  64
  65                 public CancellationTokenRegistration Register (Action callback, bool useSynchronizationContext)
  66                 {
  67                         if (callback == null)
  68                                 throw new ArgumentNullException ("callback");
  69
  70                         return Source.Register (callback, useSynchronizationContext);
  71                 }
  72
  73                 public CancellationTokenRegistration Register (Action<object> callback, object state)
  74                 {
  75                         return Register (callback, state, false);
  76                 }
  77
  78                 public CancellationTokenRegistration Register (Action<object> callback, object state, bool useSynchronizationContext)
  79                 {
  80                         if (callback == null)
  81                                 throw new ArgumentNullException ("callback");
  82
  83                         return Register (() => callback (state), useSynchronizationContext);
  84                 }
  85
  86                 public void ThrowIfCancellationRequested ()
  87                 {
  88                         if (Source.IsCancellationRequested)
  89                                 throw new OperationCanceledException (this);
  90                 }
  91
  92                 public bool Equals (CancellationToken other)
  93                 {
  94                         return this.Source == other.Source;
  95                 }
  96
  97                 public override bool Equals (object other)
  98                 {
  99                         return (other is CancellationToken) ? Equals ((CancellationToken)other) : false;
 100                 }
 101
 102                 public override int GetHashCode ()
 103                 {
 104                         return Source.GetHashCode ();
 105                 }
 106
 107                 public static bool operator == (CancellationToken left, CancellationToken right)
 108                 {
 109                         return left.Equals (right);
 110                 }
 111
 112                 public static bool operator != (CancellationToken left, CancellationToken right)
 113                 {
 114                         return !left.Equals (right);
 115                 }
 116
 117                 public bool CanBeCanceled {
 118                         get {
 119                                 return source != null;
 120                         }
 121                 }
 122
 123                 public bool IsCancellationRequested {
 124                         get {
 125                                 return Source.IsCancellationRequested;
 126                         }
 127                 }
 128
 129                 public WaitHandle WaitHandle {
 130                         get {
 131                                 return Source.WaitHandle;
 132                         }
 133                 }
 134
 135                 CancellationTokenSource Source {
 136                         get {
 137                                 return source ?? CancellationTokenSource.NoneSource;
 138                         }
 139                 }
 140         }
 141 }
 142 #endif