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

   1 //
   2 // CancellationToken.cs
   3 //
   4 // Author:
   5 //       Jérémie "Garuma" Laval <jeremie.laval@gmail.com>
   6 //
   7 // Copyright (c) 2009 Jérémie "Garuma" Laval
   8 //
   9 // Permission is hereby granted, free of charge, to any person obtaining a copy
  10 // of this software and associated documentation files (the "Software"), to deal
  11 // in the Software without restriction, including without limitation the rights
  12 // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  13 // copies of the Software, and to permit persons to whom the Software is
  14 // furnished to do so, subject to the following conditions:
  15 //
  16 // The above copyright notice and this permission notice shall be included in
  17 // all copies or substantial portions of the Software.
  18 //
  19 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  20 // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  21 // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  22 // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  23 // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  24 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  25 // THE SOFTWARE.
  26
  27 using System;
  28 using System.Threading;
  29
  30 #if NET_4_0 || MOBILE
  31 namespace System.Threading
  32 {
  33         [System.Diagnostics.DebuggerDisplay ("IsCancellationRequested = {IsCancellationRequested}")]
  34         public struct CancellationToken
  35         {
  36                 bool canBeCanceled;
  37                 bool initialized;
  38                 CancellationTokenSource source;
  39
  40                 public CancellationToken (bool canceled)
  41                         : this ()
  42                 {
  43                         initialized = true;
  44                         canBeCanceled = canceled;
  45                         // This is correctly set later if token originates from a Source
  46                         source = canceled ? CancellationTokenSource.CanceledSource : CancellationTokenSource.NoneSource;
  47                 }
  48
  49                 public static CancellationToken None {
  50                         get {
  51                                 return CancellationTokenSource.NoneSource.Token;
  52                         }
  53                 }
  54
  55                 public CancellationTokenRegistration Register (Action callback)
  56                 {
  57                         return Register (callback, false);
  58                 }
  59
  60                 public CancellationTokenRegistration Register (Action callback, bool useSynchronizationContext)
  61                 {
  62                         if (callback == null)
  63                                 throw new ArgumentNullException ("callback");
  64
  65                         return Source.Register (callback, useSynchronizationContext);
  66                 }
  67
  68                 public CancellationTokenRegistration Register (Action<object> callback, object state)
  69                 {
  70                         return Register (callback, state, false);
  71                 }
  72
  73                 public CancellationTokenRegistration Register (Action<object> callback, object state, bool useSynchronizationContext)
  74                 {
  75                         if (callback == null)
  76                                 throw new ArgumentNullException ("callback");
  77
  78                         return Register (() => callback (state), useSynchronizationContext);
  79                 }
  80
  81                 public void ThrowIfCancellationRequested ()
  82                 {
  83                         if (initialized && Source.IsCancellationRequested)
  84                                 throw new OperationCanceledException (this);
  85                 }
  86
  87                 public bool Equals (CancellationToken other)
  88                 {
  89                         return this.Source == other.Source;
  90                 }
  91
  92                 public override bool Equals (object other)
  93                 {
  94                         return (other is CancellationToken) ? Equals ((CancellationToken)other) : false;
  95                 }
  96
  97                 public override int GetHashCode ()
  98                 {
  99                         return Source.GetHashCode ();
 100                 }
 101
 102                 public static bool operator == (CancellationToken left, CancellationToken right)
 103                 {
 104                         return left.Equals (right);
 105                 }
 106
 107                 public static bool operator != (CancellationToken left, CancellationToken right)
 108                 {
 109                         return !left.Equals (right);
 110                 }
 111
 112                 public bool CanBeCanceled {
 113                         get {
 114                                 return canBeCanceled;
 115                         }
 116                 }
 117
 118                 public bool IsCancellationRequested {
 119                         get {
 120                                 return initialized && Source.IsCancellationRequested;
 121                         }
 122                 }
 123
 124                 public WaitHandle WaitHandle {
 125                         get {
 126                                 return Source.WaitHandle;
 127                         }
 128                 }
 129
 130                 internal CancellationTokenSource Source {
 131                         get {
 132                                 if (!initialized)
 133                                         CorrectlyInitialize ();
 134                                 return source;
 135                         }
 136                         set {
 137                                 source = value;
 138                         }
 139                 }
 140
 141                 void CorrectlyInitialize ()
 142                 {
 143                         Source = CancellationTokenSource.NoneSource;
 144                         initialized = true;
 145                 }
 146         }
 147 }
 148 #endif