public static IAsyncObservable <TSource> While <TSource>(Func <Task <bool> > condition, IAsyncObservable <TSource> source)
{
if (condition == null)
{
throw new ArgumentNullException(nameof(condition));
}
if (source == null)
{
throw new ArgumentNullException(nameof(source));
}
return(Create <TSource>(async observer =>
{
var subscription = new SerialAsyncDisposable();
var o = default(IAsyncObserver <TSource>);
o = AsyncObserver.CreateUnsafe <TSource>(
observer.OnNextAsync,
observer.OnErrorAsync,
MoveNext
);
async ValueTask MoveNext()
{
var b = default(bool);
try
{
b = await condition().ConfigureAwait(false);
}
catch (Exception ex)
{
await observer.OnErrorAsync(ex).ConfigureAwait(false);
return;
}
if (b)
{
var sad = new SingleAssignmentAsyncDisposable();
await subscription.AssignAsync(sad).ConfigureAwait(false);
var d = await source.SubscribeSafeAsync(o).ConfigureAwait(false);
await sad.AssignAsync(d).ConfigureAwait(false);
}
else
{
await observer.OnCompletedAsync().ConfigureAwait(false);
}
}
await MoveNext().ConfigureAwait(false);
return subscription;
}));
}
public static IAsyncObservable <TResult> For <TSource, TResult>(IEnumerable <TSource> source, Func <TSource, Task <IAsyncObservable <TResult> > > resultSelector)
{
if (source == null)
{
throw new ArgumentNullException(nameof(source));
}
if (resultSelector == null)
{
throw new ArgumentNullException(nameof(resultSelector));
}
return(Create <TResult>(async observer =>
{
var subscription = new SerialAsyncDisposable();
var enumerator = source.GetEnumerator();
var o = default(IAsyncObserver <TResult>);
o = AsyncObserver.CreateUnsafe <TResult>(
observer.OnNextAsync,
observer.OnErrorAsync,
MoveNext
);
async Task MoveNext()
{
var b = default(bool);
var next = default(IAsyncObservable <TResult>);
try
{
b = enumerator.MoveNext();
if (b)
{
next = await resultSelector(enumerator.Current).ConfigureAwait(false);
}
}
catch (Exception ex)
{
await observer.OnErrorAsync(ex).ConfigureAwait(false);
return;
}
if (b)
{
var sad = new SingleAssignmentAsyncDisposable();
await subscription.AssignAsync(sad).ConfigureAwait(false);
var d = await next.SubscribeSafeAsync(o).ConfigureAwait(false);
await sad.AssignAsync(d).ConfigureAwait(false);
}
else
{
await observer.OnCompletedAsync().ConfigureAwait(false);
}
}
await MoveNext().ConfigureAwait(false);
var disposeEnumerator = AsyncDisposable.Create(() =>
{
enumerator.Dispose();
return Task.CompletedTask;
});
return StableCompositeAsyncDisposable.Create(disposeEnumerator, subscription);
}));
}