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comparison Implab/ActionChainTaskBase.cs @ 187:dd4a3590f9c6 ref20160224

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Reworked cancelation handling, if the cancel handler isn't specified the OperationCanceledException will be handled by the error handler Any unhandled OperationCanceledException will cause the promise cancelation
author cin
date Tue, 19 Apr 2016 17:35:20 +0300
parents 75103928da09
children 40d7fed4a09e
comparison
equal deleted inserted replaced
186:75103928da09 187:dd4a3590f9c6
1 using System; 1 using System;
2 using System.Threading; 2 using System.Threading;
3 3
4 namespace Implab { 4 namespace Implab {
5 public class ActionChainTaskBase : AbstractPromise { 5 public class ActionChainTaskBase : AbstractTask {
6 readonly Func<Exception, IPromise> m_error; 6 readonly Func<Exception, IPromise> m_error;
7 readonly Func<Exception, IPromise> m_cancel; 7 readonly Func<Exception, IPromise> m_cancel;
8
9 int m_cancelationLock;
10 8
11 protected ActionChainTaskBase(Func<Exception, IPromise> error, Func<Exception, IPromise> cancel, bool autoCancellable) { 9 protected ActionChainTaskBase(Func<Exception, IPromise> error, Func<Exception, IPromise> cancel, bool autoCancellable) {
12 m_error = error; 10 m_error = error;
13 m_cancel = cancel; 11 m_cancel = cancel;
14 if (autoCancellable) 12 if (autoCancellable)
19 if (LockCancelation()) 17 if (LockCancelation())
20 HandleErrorInternal(error); 18 HandleErrorInternal(error);
21 } 19 }
22 20
23 public override void CancelOperation(Exception reason) { 21 public override void CancelOperation(Exception reason) {
24 if (LockCancelation()) { 22 if (LockCancelation())
25 if (!(reason is OperationCanceledException)) 23 // отмена вызвана до начала выполнения задачи
26 reason = reason != null ? new OperationCanceledException(null, reason) : new OperationCanceledException(); 24 HandleCancelInternal(reason);
27 25 }
28 if (m_cancel != null) { 26
29 try { 27 protected void HandleCancelInternal(Exception reason) {
30 m_cancel(reason).On(SetResult, HandleErrorInternal, HandleCancelInternal); 28 if (m_cancel != null) {
31 } catch (Exception err) { 29 try {
32 HandleErrorInternal(err); 30 // вызываем обработчик отмены
33 } 31 var p = m_cancel(reason);
34 } else { 32 p.On(SetResult, HandleErrorInternal, SetCancelledInternal);
35 HandleErrorInternal(reason); 33 // сообщаем асинхронной операции, что клиент уже не хочет получать результат
34 // т.е. если он инициировал отмену, задача отменилась, вызвался обрабочик отмены
35 // отбработчику сообщили, что результат уже не нужен и уже сам обработчик решает
36 // отдавать ли результат или подтвердить отмену (или вернуть ошибку).
37 CancellationRequested(p.Cancel);
38 } catch (Exception err) {
39 HandleErrorInternal(err);
36 } 40 }
41 } else {
42 HandleErrorInternal(reason ?? new OperationCanceledException());
37 } 43 }
38 } 44 }
39 45
40 void HandleCancelInternal(Exception reason) { 46 protected void HandleErrorInternal(Exception error) {
41 if (!(reason is OperationCanceledException))
42 reason = reason != null ? new OperationCanceledException(null, reason) : new OperationCanceledException();
43 HandleErrorInternal(reason);
44 }
45
46 void HandleErrorInternal(Exception error) {
47 if (m_error != null) { 47 if (m_error != null) {
48 try { 48 try {
49 var p = m_error(error); 49 var p = m_error(error);
50 p.On(SetResult, SetError, SetCancelled); 50 p.On(SetResult, SetErrorInternal, SetCancelledInternal);
51 CancellationRequested(p.Cancel); 51 CancellationRequested(p.Cancel);
52 } catch (Exception err) { 52 } catch (Exception err) {
53 error = err; 53 SetErrorInternal(error);
54 } 54 }
55 } else { 55 } else {
56 SetErrorInternal(error); 56 SetErrorInternal(error);
57 } 57 }
58 } 58 }
59 59
60 void SetErrorInternal(Exception error) {
61 while (error is PromiseTransientException)
62 error = error.InnerException;
63
64 if (error is OperationCanceledException)
65 SetCancelled(error);
66 else
67 SetError(error);
68 }
69
70 protected bool LockCancelation() {
71 return 0 == Interlocked.CompareExchange(ref m_cancelationLock, 1, 0);
72 }
73 } 60 }
74 } 61 }
75 62