using System.Reactive.Disposables; using System.Reactive.Subjects; namespace System.Reactive.Linq.ObservableImpl { internal sealed class RefCount<TSource> : Producer<TSource, RefCount<TSource>._> { internal sealed class _ : Sink<TSource>, IObserver<TSource> { public _(IObserver<TSource> observer, IDisposable cancel) : base(observer, cancel) { } public IDisposable Run(RefCount<TSource> parent) { IDisposable subscription = ObservableExtensions.SubscribeSafe<TSource>((IObservable<TSource>)parent._source, (IObserver<TSource>)this); lock (parent._gate) { if (++parent._count == 1) parent._connectableSubscription = parent._source.Connect(); } return Disposable.Create(delegate { subscription.Dispose(); lock (parent._gate) { if (--parent._count == 0) parent._connectableSubscription.Dispose(); } }); } public void OnNext(TSource value) { _observer.OnNext(value); } public void OnError(Exception error) { _observer.OnError(error); base.Dispose(); } public void OnCompleted() { _observer.OnCompleted(); base.Dispose(); } } private readonly IConnectableObservable<TSource> _source; private readonly object _gate; private int _count; private IDisposable _connectableSubscription; public RefCount(IConnectableObservable<TSource> source) { _source = source; _gate = new object(); _count = 0; _connectableSubscription = null; } protected override _ CreateSink(IObserver<TSource> observer, IDisposable cancel) { return new _(observer, cancel); } protected override IDisposable Run(_ sink) { return sink.Run(this); } } }