namespace System.Reactive.Linq.ObservableImpl { internal static class Count<TSource> { internal sealed class All : Producer<int, All._> { internal sealed class _ : Sink<TSource, int> { private int _count; public _(IObserver<int> observer) : base(observer) { } public override void OnNext(TSource value) { checked { try { _count++; } catch (Exception error) { ForwardOnError(error); } } } public override void OnCompleted() { ForwardOnNext(_count); ForwardOnCompleted(); } } private readonly IObservable<TSource> _source; public All(IObservable<TSource> source) { _source = source; } protected override _ CreateSink(IObserver<int> observer) { return new _(observer); } protected override void Run(_ sink) { sink.Run(_source); } } internal sealed class Predicate : Producer<int, Predicate._> { internal sealed class _ : Sink<TSource, int> { private readonly Func<TSource, bool> _predicate; private int _count; public _(Func<TSource, bool> predicate, IObserver<int> observer) : base(observer) { _predicate = predicate; } public override void OnNext(TSource value) { checked { try { if (_predicate(value)) _count++; } catch (Exception error) { ForwardOnError(error); } } } public override void OnCompleted() { ForwardOnNext(_count); ForwardOnCompleted(); } } private readonly IObservable<TSource> _source; private readonly Func<TSource, bool> _predicate; public Predicate(IObservable<TSource> source, Func<TSource, bool> predicate) { _source = source; _predicate = predicate; } protected override _ CreateSink(IObserver<int> observer) { return new _(_predicate, observer); } protected override void Run(_ sink) { sink.Run(_source); } } } }