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

   1 #if NET_4_0
   2 //
   3 // TaskCompletionSource.cs
   4 //
   5 // Author:
   6 //       Jérémie "Garuma" Laval <jeremie.laval@gmail.com>
   7 //
   8 // Copyright (c) 2009 Jérémie "Garuma" Laval
   9 //
  10 // Permission is hereby granted, free of charge, to any person obtaining a copy
  11 // of this software and associated documentation files (the "Software"), to deal
  12 // in the Software without restriction, including without limitation the rights
  13 // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  14 // copies of the Software, and to permit persons to whom the Software is
  15 // furnished to do so, subject to the following conditions:
  16 //
  17 // The above copyright notice and this permission notice shall be included in
  18 // all copies or substantial portions of the Software.
  19 //
  20 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  21 // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  22 // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  23 // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  24 // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  25 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  26 // THE SOFTWARE.
  27
  28 using System;
  29
  30 namespace System.Threading.Tasks
  31 {
  32         public class TaskCompletionSource<TResult>
  33         {
  34                 Task<TResult> source;
  35
  36                 public TaskCompletionSource ()
  37                 {
  38                         source = new Task<TResult> (null);
  39                 }
  40
  41                 public TaskCompletionSource (object state)
  42                 {
  43                         source = new Task<TResult> (null, state);
  44                 }
  45
  46                 public TaskCompletionSource (TaskCreationOptions options)
  47                 {
  48                         source = new Task<TResult> (null, options);
  49                 }
  50
  51                 public TaskCompletionSource (object state, TaskCreationOptions options)
  52                 {
  53                         source = new Task<TResult> (null, state, options);
  54                 }
  55
  56                 public void SetCanceled ()
  57                 {
  58                         if (!ApplyOperation (TaskStatus.Canceled, () => { source.Cancel (); source.CancelReal (); }))
  59                                 ThrowInvalidException ();
  60                 }
  61
  62                 public void SetException (Exception e)
  63                 {
  64                         if (!ApplyOperation (TaskStatus.Faulted, () => source.Exception = e))
  65                                 ThrowInvalidException ();
  66                 }
  67
  68                 public void SetResult (TResult result)
  69                 {
  70                         if (!ApplyOperation (TaskStatus.RanToCompletion, () => source.Result = result))
  71                                 ThrowInvalidException ();
  72                 }
  73
  74                 void ThrowInvalidException ()
  75                 {
  76                         throw new InvalidOperationException ("The underlying Task is already in one of the three final states: RanToCompletion, Faulted, or Canceled.");
  77                 }
  78
  79                 public bool TrySetCanceled ()
  80                 {
  81                         return ApplyOperation (TaskStatus.Canceled, () => { source.Cancel (); source.CancelReal (); });
  82                 }
  83
  84                 public bool TrySetException (Exception e)
  85                 {
  86                         return ApplyOperation (TaskStatus.Faulted, () => source.Exception = e);
  87                 }
  88
  89                 public bool TrySetResult (TResult result)
  90                 {
  91                         return ApplyOperation (TaskStatus.RanToCompletion, () => source.Result = result);
  92                 }
  93
  94                 bool ApplyOperation (TaskStatus newStatus, Action action)
  95                 {
  96                         if (CheckInvalidState ())
  97                                 return false;
  98
  99                         if (action != null)
 100                                 action ();
 101                         source.Status = newStatus;
 102
 103                         return true;
 104                 }
 105
 106                 bool CheckInvalidState ()
 107                 {
 108                         return source.Status == TaskStatus.RanToCompletion ||
 109                                    source.Status == TaskStatus.Faulted ||
 110                                    source.Status == TaskStatus.Canceled;
 111
 112                 }
 113
 114                 public Task<TResult> Task {
 115                         get {
 116                                 return source;
 117                         }
 118                 }
 119         }
 120 }
 121 #endif