public static Task InvokeAsync(Func <Task> func)
{
TaskCompletionSource <object> tcl = new TaskCompletionSource <object>( );
ThreadPool.QueueUserWorkItem(
_ => {
Task rt = func( );
ConfiguredTaskAwaitable.ConfiguredTaskAwaiter cta =
rt.ConfigureAwait(false).GetAwaiter( );
cta.OnCompleted(
() => {
if (rt.IsCanceled)
{
tcl.SetCanceled( );
}
else if (rt.IsFaulted)
{
// ReSharper disable once AssignNullToNotNullAttribute
tcl.SetException(rt.Exception);
}
else
{
tcl.SetResult(null);
}
});
});
return(tcl.Task);
}
private void Execute()
{
try
{
switch (state)
{
case BeginInitState:
voidAwaiter = System.Threading.Tasks.Task.Delay(dueTime, cancellation.Token).ConfigureAwait(false).GetAwaiter();
if (voidAwaiter.IsCompleted)
{
goto case EndInitState;
}
state = EndInitState;
voidAwaiter.OnCompleted(continuation);
break;
case EndInitState:
voidAwaiter.GetResult();
voidAwaiter = default;
goto case BeginLoopState;
case BeginLoopState:
boolAwaiter = callback.Invoke(cancellation.Token).ConfigureAwait(false).GetAwaiter();
if (boolAwaiter.IsCompleted)
{
goto case EndLoopState;
}
state = EndLoopState;
boolAwaiter.OnCompleted(continuation);
break;
case EndLoopState:
var success = boolAwaiter.GetResult();
boolAwaiter = default;
if (success)
{
goto case BeginDelayState;
}
TrySetResult(true);
break;
case BeginDelayState:
voidAwaiter = System.Threading.Tasks.Task.Delay(period, cancellation.Token).ConfigureAwait(false).GetAwaiter();
if (voidAwaiter.IsCompleted)
{
goto case EndDelayState;
}
state = EndDelayState;
voidAwaiter.OnCompleted(continuation);
break;
case EndDelayState:
voidAwaiter.GetResult();
voidAwaiter = default;
goto case BeginLoopState;
}
}
catch (OperationCanceledException)
{
TrySetResult(false);
}
catch (Exception e)
{
TrySetException(e);
}
if (Task.IsCompleted)
{
cancellation.Dispose();
}
}
/// <summary>Schedules the continuation action for these tasks.</summary> public void OnCompleted(Action continuation) => _awaiter.OnCompleted(continuation);
public override void OnCompleted(Action continuation) => awaiter.OnCompleted(continuation);
void INotifyCompletion.OnCompleted(Action continuation) => taskAwaiter.OnCompleted(continuation);
public void OnCompleted(Action continuation) => _taskAwaiter.OnCompleted(WrapContinuation(continuation));
public void OnCompleted(Action continuation)
{
_operationContext = OperationContext.Current;
_awaiter.OnCompleted(continuation);
}