mcs/class/corlib/System.Threading.Tasks/TaskCompletionSource.cs

   1 //
   2 // TaskCompletionSource.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 #if NET_4_0 || BOOTSTRAP_NET_4_0
  28 using System;
  29 using System.Collections.Generic;
  30
  31 namespace System.Threading.Tasks
  32 {
  33         public class TaskCompletionSource<TResult>
  34         {
  35                 Task<TResult> source;
  36
  37                 public TaskCompletionSource ()
  38                 {
  39                         source = new Task<TResult> (null);
  40                         source.SetupScheduler (TaskScheduler.Current);
  41                 }
  42
  43                 public TaskCompletionSource (object state)
  44                 {
  45                         source = new Task<TResult> (null, state);
  46                         source.SetupScheduler (TaskScheduler.Current);
  47                 }
  48
  49                 public TaskCompletionSource (TaskCreationOptions options)
  50                 {
  51                         source = new Task<TResult> (null, options);
  52                         source.SetupScheduler (TaskScheduler.Current);
  53                 }
  54
  55                 public TaskCompletionSource (object state, TaskCreationOptions options)
  56                 {
  57                         source = new Task<TResult> (null, state, options);
  58                         source.SetupScheduler (TaskScheduler.Current);
  59                 }
  60
  61                 public void SetCanceled ()
  62                 {
  63                         if (!ApplyOperation (source.CancelReal))
  64                                 ThrowInvalidException ();
  65                 }
  66
  67                 public void SetException (Exception e)
  68                 {
  69                         SetException (new Exception[] { e });
  70                 }
  71
  72                 public void SetException (IEnumerable<Exception> e)
  73                 {
  74                         if (!ApplyOperation (() => source.HandleGenericException (new AggregateException (e))))
  75                                 ThrowInvalidException ();
  76                 }
  77
  78                 public void SetResult (TResult result)
  79                 {
  80                         if (!ApplyOperation (() => source.Result = result))
  81                                 ThrowInvalidException ();
  82                 }
  83
  84                 void ThrowInvalidException ()
  85                 {
  86                         throw new InvalidOperationException ("The underlying Task is already in one of the three final states: RanToCompletion, Faulted, or Canceled.");
  87                 }
  88
  89                 public bool TrySetCanceled ()
  90                 {
  91                         return ApplyOperation (source.CancelReal);
  92                 }
  93
  94                 public bool TrySetException (Exception e)
  95                 {
  96                         return TrySetException (new Exception[] { e });
  97                 }
  98
  99                 public bool TrySetException (IEnumerable<Exception> e)
 100                 {
 101                         return ApplyOperation (() => source.HandleGenericException (new AggregateException (e)));
 102                 }
 103
 104                 public bool TrySetResult (TResult result)
 105                 {
 106                         return ApplyOperation (() => source.Result = result);
 107                 }
 108
 109                 bool ApplyOperation (Action action)
 110                 {
 111                         if (CheckInvalidState ())
 112                                 return false;
 113
 114                         source.Status = TaskStatus.Running;
 115
 116                         if (action != null)
 117                                 action ();
 118
 119                         source.Finish ();
 120
 121                         return true;
 122                 }
 123
 124                 bool CheckInvalidState ()
 125                 {
 126                         return source.Status == TaskStatus.RanToCompletion ||
 127                                    source.Status == TaskStatus.Faulted ||
 128                                    source.Status == TaskStatus.Canceled;
 129
 130                 }
 131
 132                 public Task<TResult> Task {
 133                         get {
 134                                 return source;
 135                         }
 136                 }
 137         }
 138 }
 139 #endif