52 lines
1.5 KiB
C#
52 lines
1.5 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 DefaultIfEmpty<TSource> : Producer<TSource, DefaultIfEmpty<TSource>._>
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{
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private readonly IObservable<TSource> _source;
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private readonly TSource _defaultValue;
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public DefaultIfEmpty(IObservable<TSource> source, TSource defaultValue)
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{
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_source = source;
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_defaultValue = defaultValue;
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}
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protected override _ CreateSink(IObserver<TSource> observer) => new(_defaultValue, 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 readonly TSource _defaultValue;
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private bool _found;
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public _(TSource defaultValue, IObserver<TSource> observer)
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: base(observer)
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{
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_defaultValue = defaultValue;
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_found = false;
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}
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public override void OnNext(TSource value)
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{
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_found = true;
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ForwardOnNext(value);
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}
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public override void OnCompleted()
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{
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if (!_found)
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{
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ForwardOnNext(_defaultValue);
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}
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ForwardOnCompleted();
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}
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}
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}
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}
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