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comparison Implab/ActionChainTaskBase.cs @ 145:706fccb85524 v2

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RC: cancellation support for promises + tests
author cin
date Sun, 08 Mar 2015 02:52:27 +0300
parents
children eb793fbbe4ea
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144:8c0b95069066 145:706fccb85524
1 using System;
2 using System.Threading;
3
4 namespace Implab {
5 public class ActionChainTaskBase : AbstractPromise {
6 readonly Func<Exception, IPromise> m_error;
7 readonly Func<Exception, IPromise> m_cancel;
8
9 int m_cancelationLock;
10
11 protected ActionChainTaskBase( Func<Exception, IPromise> error, Func<Exception, IPromise> cancel) {
12 m_error = error;
13 m_cancel = cancel;
14 }
15
16 public void Reject(Exception error) {
17 if (LockCancelation())
18 HandleErrorInternal(error);
19 }
20
21
22
23 public override void CancelOperation(Exception reason) {
24 if (m_cancel != null && LockCancelation()) {
25 try {
26 Observe(m_cancel(reason));
27 } catch(Exception err) {
28 HandleErrorInternal(err);
29 }
30 }
31
32 }
33
34 protected void HandleErrorInternal(Exception error) {
35 if (m_error != null) {
36 try {
37 Observe(m_error(error));
38 } catch(Exception err) {
39 SetError(err);
40 }
41 } else {
42 SetError(error);
43 }
44 }
45
46 protected void Observe(IPromise operation) {
47 if (operation == null)
48 throw new NullReferenceException("The task returned null promise");
49
50 // pass operation results to the current promise
51 operation.On(SetResult, SetError, SetCancelled);
52
53 // pass the cancelation request
54 CancellationRequested(operation.Cancel);
55 }
56
57 protected bool LockCancelation() {
58 return 0 == Interlocked.CompareExchange(ref m_cancelationLock, 1, 0);
59 }
60 }
61 }
62