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