using System.Collections; using System.Collections.Generic; using System.Reactive.Disposables; namespace System.Reactive.Linq.ObservableImpl { internal abstract class PushToPullSink<TSource, TResult> : IObserver<TSource>, IEnumerator<TResult>, IEnumerator, IDisposable { private IDisposable _upstream; private bool _done; public TResult Current { get; set; } object IEnumerator.Current { get { return Current; } } public abstract void OnNext(TSource value); public abstract void OnError(Exception error); public abstract void OnCompleted(); public abstract bool TryMoveNext(out TResult current); public bool MoveNext() { if (!_done) { if (TryMoveNext(out TResult current)) { Current = current; return true; } _done = true; Dispose(); } return false; } public void Reset() { throw new NotSupportedException(); } public void Dispose() { Disposable.TryDispose(ref _upstream); } public void SetUpstream(IDisposable d) { Disposable.SetSingle(ref _upstream, d); } } } namespace System.Reactive.Linq.ObservableImpl { }