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

   1 //
   2 // TaskExtensionsImpl.cs
   3 //
   4 // Authors:
   5 //       Jérémie "Garuma" Laval <jeremie.laval@gmail.com>
   6 //       Marek Safar (marek.safar@gmail.com)
   7 //
   8 // Copyright (c) 2010 Jérémie "Garuma" Laval
   9 // Copyright (C) 2013 Xamarin, Inc (http://www.xamarin.com)
  10 //
  11 // Permission is hereby granted, free of charge, to any person obtaining
  12 // a copy of this software and associated documentation files (the
  13 // "Software"), to deal in the Software without restriction, including
  14 // without limitation the rights to use, copy, modify, merge, publish,
  15 // distribute, sublicense, and/or sell copies of the Software, and to
  16 // permit persons to whom the Software is furnished to do so, subject to
  17 // the following conditions:
  18 //
  19 // The above copyright notice and this permission notice shall be
  20 // included in all copies or substantial portions of the Software.
  21 //
  22 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  23 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  24 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  25 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  26 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  27 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  28 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  29 //
  30
  31 #if NET_4_0
  32
  33 namespace System.Threading.Tasks
  34 {
  35         static class TaskExtensionsImpl
  36         {
  37                 const TaskContinuationOptions options = TaskContinuationOptions.ExecuteSynchronously;
  38
  39                 public static Task<TResult> Unwrap<TResult> (Task<Task<TResult>> task)
  40                 {
  41                         var src = new TaskCompletionSource<TResult> ();
  42                         task.ContinueWith ((t, arg) => Cont (t, (TaskCompletionSource<TResult>) arg), src, CancellationToken.None, options, TaskScheduler.Current);
  43
  44                         return src.Task;
  45                 }
  46
  47                 public static Task Unwrap (Task<Task> task)
  48                 {
  49                         var src = new TaskCompletionSource<object> ();
  50                         task.ContinueWith ((t, arg) => Cont (t, (TaskCompletionSource<object>) arg), src, CancellationToken.None, options, TaskScheduler.Current);
  51
  52                         return src.Task;
  53                 }
  54
  55                 static void SetResult (Task source, TaskCompletionSource<object> dest)
  56                 {
  57                         if (source.IsCanceled)
  58                                 dest.SetCanceled ();
  59                         else if (source.IsFaulted)
  60                                 dest.SetException (source.Exception.InnerExceptions);
  61                         else
  62                                 dest.SetResult (null);
  63                 }
  64
  65                 static void Cont (Task<Task> source, TaskCompletionSource<object> dest)
  66                 {
  67                         if (source.IsCanceled)
  68                                 dest.SetCanceled ();
  69                         else if (source.IsFaulted)
  70                                 dest.SetException (source.Exception.InnerExceptions);
  71                         else
  72                                 source.Result.ContinueWith ((t, arg) => SetResult (t, (TaskCompletionSource<object>) arg), dest, CancellationToken.None, options, TaskScheduler.Current);
  73                 }
  74
  75                 static void SetResult<TResult> (Task<TResult> source, TaskCompletionSource<TResult> dest)
  76                 {
  77                         if (source.IsCanceled)
  78                                 dest.SetCanceled ();
  79                         else if (source.IsFaulted)
  80                                 dest.SetException (source.Exception.InnerExceptions);
  81                         else
  82                                 dest.SetResult (source.Result);
  83                 }
  84
  85                 static void Cont<TResult> (Task<Task<TResult>> source, TaskCompletionSource<TResult> dest)
  86                 {
  87                         if (source.IsCanceled)
  88                                 dest.SetCanceled ();
  89                         else if (source.IsFaulted)
  90                                 dest.SetException (source.Exception.InnerExceptions);
  91                         else
  92                                 source.Result.ContinueWith ((t, arg) => SetResult (t, (TaskCompletionSource<TResult>) arg), dest, CancellationToken.None, options, TaskScheduler.Current);
  93                 }
  94         }
  95 }
  96
  97 #endif