namespace System.Reactive.Linq.ObservableImpl { internal sealed class TakeUntilPredicate<TSource> : Producer<TSource, TakeUntilPredicate<TSource>.TakeUntilPredicateObserver> { internal sealed class TakeUntilPredicateObserver : IdentitySink<TSource> { private readonly Func<TSource, bool> _stopPredicate; public TakeUntilPredicateObserver(IObserver<TSource> downstream, Func<TSource, bool> predicate) : base(downstream) { _stopPredicate = predicate; } public override void OnCompleted() { ForwardOnCompleted(); } public override void OnError(Exception error) { ForwardOnError(error); } public override void OnNext(TSource value) { ForwardOnNext(value); bool flag = false; try { flag = _stopPredicate(value); } catch (Exception error) { ForwardOnError(error); return; } if (flag) ForwardOnCompleted(); } } private readonly IObservable<TSource> _source; private readonly Func<TSource, bool> _stopPredicate; public TakeUntilPredicate(IObservable<TSource> source, Func<TSource, bool> stopPredicate) { _source = source; _stopPredicate = stopPredicate; } protected override TakeUntilPredicateObserver CreateSink(IObserver<TSource> observer) { return new TakeUntilPredicateObserver(observer, _stopPredicate); } protected override void Run(TakeUntilPredicateObserver sink) { sink.Run(_source); } } }