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