60 lines
1.6 KiB
C#
60 lines
1.6 KiB
C#
// Licensed to the .NET Foundation under one or more agreements.
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// The .NET Foundation licenses this file to you under the MIT License.
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// See the LICENSE file in the project root for more information.
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namespace System.Reactive.Linq.ObservableImpl
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{
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internal sealed class ElementAt<TSource> : Producer<TSource, ElementAt<TSource>._>
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{
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private readonly IObservable<TSource> _source;
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private readonly int _index;
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public ElementAt(IObservable<TSource> source, int index)
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{
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_source = source;
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_index = index;
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}
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protected override _ CreateSink(IObserver<TSource> observer) => new(_index, observer);
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protected override void Run(_ sink) => sink.Run(_source);
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internal sealed class _ : IdentitySink<TSource>
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{
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private int _i;
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public _(int index, IObserver<TSource> observer)
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: base(observer)
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{
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_i = index;
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}
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public override void OnNext(TSource value)
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{
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if (_i == 0)
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{
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ForwardOnNext(value);
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ForwardOnCompleted();
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}
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_i--;
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}
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public override void OnCompleted()
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{
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if (_i >= 0)
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{
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try
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{
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throw new ArgumentOutOfRangeException("index");
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}
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catch (Exception e)
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{
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ForwardOnError(e);
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}
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}
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}
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}
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}
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}
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