root / trunk / Pithos.Core / TaskExtensions.cs @ cfed7823
History | View | Annotate | Download (4.5 kB)
1 |
using System; |
---|---|
2 |
using System.Collections.Generic; |
3 |
using System.Diagnostics.Contracts; |
4 |
using System.Linq; |
5 |
using System.Text; |
6 |
using System.Threading; |
7 |
using System.Threading.Tasks; |
8 |
|
9 |
namespace Pithos.Core |
10 |
{ |
11 |
static class TaskExtensions |
12 |
{ |
13 |
public static Task<T2> Then<T1, T2>(this Task<T1> first, Func<T1, Task<T2>> next) |
14 |
{ |
15 |
if (first == null) |
16 |
throw new ArgumentNullException("first"); |
17 |
if (next == null) |
18 |
throw new ArgumentNullException("next"); |
19 |
Contract.EndContractBlock(); |
20 |
return Then(first, next, CancellationToken.None); |
21 |
} |
22 |
|
23 |
public static Task Then<T1>(this Task<T1> first, Func<T1, Task> next) |
24 |
{ |
25 |
if (first == null) |
26 |
throw new ArgumentNullException("first"); |
27 |
if (next == null) |
28 |
throw new ArgumentNullException("next"); |
29 |
Contract.EndContractBlock(); |
30 |
return Then(first, next, CancellationToken.None); |
31 |
} |
32 |
|
33 |
public static Task<T2> Then<T1, T2>(this Task<T1> first, Func<T1, Task<T2>> next, CancellationToken cancellationToken) |
34 |
{ |
35 |
if (first == null) |
36 |
throw new ArgumentNullException("first"); |
37 |
if (next == null) |
38 |
throw new ArgumentNullException("next"); |
39 |
Contract.EndContractBlock(); |
40 |
Contract.Assume(TaskScheduler.Current!=null); |
41 |
|
42 |
var tcs = new TaskCompletionSource<T2>(); |
43 |
first.ContinueWith(delegate |
44 |
{ |
45 |
if (first.IsFaulted) tcs.TrySetException(first.Exception.InnerExceptions); |
46 |
else if (first.IsCanceled) tcs.TrySetCanceled(); |
47 |
else |
48 |
{ |
49 |
try |
50 |
{ |
51 |
var t = next(first.Result); |
52 |
if (t == null) tcs.TrySetCanceled(); |
53 |
else t.ContinueWith(delegate |
54 |
{ |
55 |
if (t.IsFaulted) tcs.TrySetException(t.Exception.InnerExceptions); |
56 |
else if (t.IsCanceled) tcs.TrySetCanceled(); |
57 |
else tcs.TrySetResult(t.Result); |
58 |
}, TaskContinuationOptions.ExecuteSynchronously); |
59 |
} |
60 |
catch (Exception exc) { tcs.TrySetException(exc); } |
61 |
} |
62 |
}, cancellationToken, TaskContinuationOptions.ExecuteSynchronously, TaskScheduler.Current); |
63 |
return tcs.Task; |
64 |
} |
65 |
|
66 |
public static Task Then<T1>(this Task<T1> first, Func<T1, Task> next, CancellationToken cancellationToken) |
67 |
{ |
68 |
if (first == null) |
69 |
throw new ArgumentNullException("first"); |
70 |
if (next == null) |
71 |
throw new ArgumentNullException("next"); |
72 |
Contract.EndContractBlock(); |
73 |
Contract.Assume(TaskScheduler.Current != null); |
74 |
|
75 |
var tcs = new TaskCompletionSource<object>(); |
76 |
first.ContinueWith(delegate |
77 |
{ |
78 |
if (first.IsFaulted) tcs.TrySetException(first.Exception.InnerExceptions); |
79 |
else if (first.IsCanceled) tcs.TrySetCanceled(); |
80 |
else |
81 |
{ |
82 |
try |
83 |
{ |
84 |
var t = next(first.Result); |
85 |
if (t == null) tcs.TrySetCanceled(); |
86 |
else t.ContinueWith(delegate |
87 |
{ |
88 |
if (t.IsFaulted) tcs.TrySetException(t.Exception.InnerExceptions); |
89 |
else if (t.IsCanceled) tcs.TrySetCanceled(); |
90 |
else tcs.TrySetResult(null); |
91 |
}, TaskContinuationOptions.ExecuteSynchronously); |
92 |
} |
93 |
catch (Exception exc) { tcs.TrySetException(exc); } |
94 |
} |
95 |
}, cancellationToken, TaskContinuationOptions.ExecuteSynchronously, TaskScheduler.Current); |
96 |
return tcs.Task; |
97 |
} |
98 |
|
99 |
|
100 |
|
101 |
public static void ReportExceptions(this Task task,Action<AggregateException> OnError,Action OnSuccess ) |
102 |
{ |
103 |
if (!task.IsCompleted) throw new InvalidOperationException("The task has not completed."); |
104 |
if (task.IsFaulted) |
105 |
task.Exception.Handle(exc=> |
106 |
{ |
107 |
OnError(task.Exception); |
108 |
return true; |
109 |
}); |
110 |
else |
111 |
{ |
112 |
OnSuccess(); |
113 |
} |
114 |
} |
115 |
|
116 |
} |
117 |
} |