Kit.Core/LibExternal/System.Reactive/Linq/Observable/TakeUntilPredicate.cs

64 lines
2.2 KiB
C#

// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT License.
// See the LICENSE file in the project root for more information.
namespace System.Reactive.Linq.ObservableImpl
{
/// <summary>
/// Relays items to the downstream until the predicate returns <code>true</code>.
/// </summary>
/// <typeparam name="TSource">The element type of the sequence</typeparam>
internal sealed class TakeUntilPredicate<TSource> :
Producer<TSource, TakeUntilPredicate<TSource>.TakeUntilPredicateObserver>
{
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) => new(observer, _stopPredicate);
protected override void Run(TakeUntilPredicateObserver sink) => sink.Run(_source);
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);
var shouldStop = false;
try
{
shouldStop = _stopPredicate(value);
}
catch (Exception ex)
{
ForwardOnError(ex);
return;
}
if (shouldStop)
{
ForwardOnCompleted();
}
}
}
}
}