static AsyncSubject <TSource> RunAsync <TSource>(IConnectableObservable <TSource> source, CancellationToken cancellationToken)
{
var s = new AsyncSubject <TSource>();
if (cancellationToken.IsCancellationRequested)
{
return(Cancel(s, cancellationToken));
}
var d = source.Subscribe(s);
var c = source.Connect();
if (cancellationToken.CanBeCanceled)
{
RegisterCancelation(s, StableCompositeDisposable.Create(d, c), cancellationToken);
}
return(s);
}
static void RegisterCancelation <T>(AsyncSubject <T> subject, IDisposable subscription, CancellationToken token)
{
//
// Separate method used to avoid heap allocation of closure when no cancellation is needed,
// e.g. when CancellationToken.None is provided to the RunAsync overloads.
//
var ctr = token.Register(() =>
{
subscription.Dispose();
Cancel(subject, token);
});
//
// No null-check for ctr is needed:
//
// - CancellationTokenRegistration is a struct
// - Registration will succeed 99% of the time, no warranting an attempt to avoid spurious Subscribe calls
//
subject.Subscribe(Stubs <T> .Ignore, _ => ctr.Dispose(), ctr.Dispose);
}
public static Func <IObservable <Unit> > ToAsync(Action action, IScheduler scheduler)
{
return(() =>
{
var subject = new AsyncSubject <Unit>();
scheduler.Schedule(() =>
{
try
{
action();
}
catch (Exception exception)
{
subject.OnError(exception);
return;
}
subject.OnNext(Unit.Default);
subject.OnCompleted();
});
return subject.AsObservable();
});
}
public void Dispose()
{
lock (gate)
{
if (parent != null)
{
lock (parent.observerLock)
{
var listObserver = parent.outObserver as ListObserver <T>;
if (listObserver != null)
{
parent.outObserver = listObserver.Remove(unsubscribeTarget);
}
else
{
parent.outObserver = EmptyObserver <T> .Instance;
}
unsubscribeTarget = null;
parent = null;
}
}
}
}
static AsyncSubject <T> Cancel <T>(AsyncSubject <T> subject, CancellationToken cancellationToken)
{
subject.OnError(new OperationCanceledException(cancellationToken));
return(subject);
}
public Subscription(AsyncSubject <T> parent, IObserver <T> unsubscribeTarget)
{
this.parent = parent;
this.unsubscribeTarget = unsubscribeTarget;
}