public static IObservable<Tuple<IDisposable<byte[]>, int>> ReadAsync(this Stream stream, int bufferSize, bool waitForObserver, bool refCount, IProducerConsumerCollection<IDisposable<byte[]>> cache)
{
var read = Observable.FromAsyncPattern<byte[], int, int, int> (stream.BeginRead, stream.EndRead);
return Observable.Create<Tuple<IDisposable<byte[]>, int>> (observer => {
var subscription = new BooleanDisposable ();
Action<Exception> onError = error => {
observer.OnError (error);
subscription.Dispose ();
};
Action loop = null;
Action<IDisposable<byte[]>, int> engine;
if (waitForObserver)
engine = (buffer, bytesRead) => {
// OnNext is called first
observer.OnNext (new Tuple<IDisposable<byte[]>, int> (buffer, bytesRead));
// then we begin async read
if (!subscription.IsDisposed)
loop ();
};
else
engine = (buffer, bytesRead) => {
// begin async read first
if (!subscription.IsDisposed)
loop ();
//then call OnNext
observer.OnNext (new Tuple<IDisposable<byte[]>, int> (buffer, bytesRead));
};
loop = () => {
var buffer = cache.TakeOrCreate (refCount, () =>
new byte[bufferSize]);
read (buffer.Value, 0, bufferSize).Subscribe (bytesRead => {
if (0 == bytesRead)
observer.OnCompleted ();
else
engine (buffer, bytesRead);
}, onError);
};
loop ();
return subscription;
});
}
