namespace System.Reactive.Linq.ObservableImpl { internal sealed class MaxInt64 : Producer<long, MaxInt64._> { internal sealed class _ : Sink<long>, IObserver<long> { private bool _hasValue; private long _lastValue; public _(IObserver<long> observer, IDisposable cancel) : base(observer, cancel) { _hasValue = false; _lastValue = 0; } public void OnNext(long value) { if (_hasValue) { if (value > _lastValue) _lastValue = value; } else { _lastValue = value; _hasValue = true; } } public void OnError(Exception error) { _observer.OnError(error); base.Dispose(); } public void OnCompleted() { if (!_hasValue) _observer.OnError(new InvalidOperationException(Strings_Linq.NO_ELEMENTS)); else { _observer.OnNext(_lastValue); _observer.OnCompleted(); } base.Dispose(); } } private readonly IObservable<long> _source; public MaxInt64(IObservable<long> source) { _source = source; } protected override _ CreateSink(IObserver<long> observer, IDisposable cancel) { return new _(observer, cancel); } protected override IDisposable Run(_ sink) { return _source.SubscribeSafe(sink); } } }