Update README.md

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Yoshifumi Kawai 2021-04-13 14:09:32 +09:00 committed by GitHub
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@ -241,6 +241,54 @@ CancellationToken can be created by `CancellationTokenSource` or MonoBehaviour's
await UniTask.DelayFrame(1000, cancellationToken: this.GetCancellationTokenOnDestroy()); await UniTask.DelayFrame(1000, cancellationToken: this.GetCancellationTokenOnDestroy());
``` ```
For propagate Cancellation, all async method recommend to accept `CancellationToken cancellationToken` at last argument, and pass `CancellationToken` from root to end.
```csharp
await FooAsync(this.GetCancellationTokenOnDestroy());
// ---
async UniTask FooAsync(CancellationToken cancellationToken)
{
await BarAsync(cancellationToken);
}
async UniTask BarAsync(CancellationToken cancellationToken)
{
await UniTask.Delay(TimeSpan.FromSeconds(3), cancellationToken);
}
```
`CancellationToken` means lifecycle of async. You can hold your own lifecycle insteadof default CancellationTokenOnDestroy.
```csharp
public class MyBehaviour : MonoBehaviour
{
CancellationTokenSource disableCancellation = new CancellationTokenSource();
CancellationTokenSource destroyCancellation = new CancellationTokenSource();
private void OnEnable()
{
if (disableCancellation != null)
{
disableCancellation.Dispose();
}
disableCancellation = new CancellationTokenSource();
}
private void OnDisable()
{
disableCancellation.Cancel();
}
private void OnDestroy()
{
destroyCancellation.Cancel();
destroyCancellation.Dispose();
}
}
```
When cancellation is detected, all methods throw `OperationCanceledException` and propagate upstream. `OperationCanceledException` is a special exception, if this exception is not handled, it is propagated finally to `UniTaskScheduler.UnobservedTaskException`. When cancellation is detected, all methods throw `OperationCanceledException` and propagate upstream. `OperationCanceledException` is a special exception, if this exception is not handled, it is propagated finally to `UniTaskScheduler.UnobservedTaskException`.
The default behaviour of received unhandled exception is to write log as exception. Log level can be changed using `UniTaskScheduler.UnobservedExceptionWriteLogType`. If you want to use custom behaviour, set an action to `UniTaskScheduler.UnobservedTaskException.` The default behaviour of received unhandled exception is to write log as exception. Log level can be changed using `UniTaskScheduler.UnobservedExceptionWriteLogType`. If you want to use custom behaviour, set an action to `UniTaskScheduler.UnobservedTaskException.`
@ -265,7 +313,7 @@ public async UniTask<int> BarAsync()
var x = await FooAsync(); var x = await FooAsync();
return x * 2; return x * 2;
} }
catch (Exception ex) when (!(ex is OperationCanceledException)) catch (Exception ex) when (!(ex is OperationCanceledException)) // when (ex is not OperationCanceledException) at C# 9.0
{ {
return -1; return -1;
} }