public static IAsyncEnumerable <TSource> ToAsyncEnumerable <TSource>(this IObservable <TSource> source)
{
if (source == null)
{
throw new ArgumentNullException("source");
}
return(Create(() =>
{
var observer = new ToAsyncEnumerableObserver <TSource>();
observer.Queue = new Queue <Either <TSource, Exception, bool> >();
var subscription = source.Subscribe(observer);
return Create(
(ct, tcs) =>
{
lock (observer.Queue)
{
if (observer.Queue.Count > 0)
{
var n = observer.Queue.Dequeue();
n.Switch(
x =>
{
observer.Current = x;
tcs.TrySetResult(true);
},
ex =>
{
tcs.TrySetException(ex);
},
_ =>
{
tcs.TrySetResult(false);
}
);
}
else
{
observer.TaskCompletionSource = tcs;
}
}
return tcs.Task;
},
() => observer.Current,
() =>
{
subscription.Dispose();
// Should we cancel in-flight operations somehow?
});
}));
}
public static IAsyncEnumerable <TSource> ToAsyncEnumerable <TSource>(this IObservable <TSource> source)
{
if (source == null)
{
throw new ArgumentNullException(nameof(source));
}
return(CreateEnumerable(
() =>
{
var observer = new ToAsyncEnumerableObserver <TSource>();
var subscription = source.Subscribe(observer);
return CreateEnumerator(
(ct, tcs) =>
{
var hasValue = false;
var hasCompleted = false;
var error = default(Exception);
lock (observer.SyncRoot)
{
if (observer.Values.Count > 0)
{
hasValue = true;
observer.Current = observer.Values.Dequeue();
}
else if (observer.HasCompleted)
{
hasCompleted = true;
}
else if (observer.Error != null)
{
error = observer.Error;
}
else
{
observer.TaskCompletionSource = tcs;
}
}
if (hasValue)
{
tcs.TrySetResult(true);
}
else if (hasCompleted)
{
tcs.TrySetResult(false);
}
else if (error != null)
{
tcs.TrySetException(error);
}
return tcs.Task;
},
() => observer.Current,
() =>
{
subscription.Dispose();
// Should we cancel in-flight operations somehow?
});
}));
}
