45 lines
1.5 KiB
C#
45 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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using System.Reactive.Subjects;
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using System.Threading;
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namespace System.Reactive.Linq.ObservableImpl
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{
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/// <summary>
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/// Automatically connect the upstream IConnectableObservable once the
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/// specified number of IObservers have subscribed to this IObservable.
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/// </summary>
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/// <typeparam name="T">The upstream value type.</typeparam>
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internal sealed class AutoConnect<T> : IObservable<T>
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{
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private readonly IConnectableObservable<T> _source;
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private readonly int _minObservers;
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private readonly Action<IDisposable>? _onConnect;
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private int _count;
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internal AutoConnect(IConnectableObservable<T> source, int minObservers, Action<IDisposable>? onConnect)
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{
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_source = source;
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_minObservers = minObservers;
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_onConnect = onConnect;
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}
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public IDisposable Subscribe(IObserver<T> observer)
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{
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var d = _source.Subscribe(observer);
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if (Volatile.Read(ref _count) < _minObservers)
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{
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if (Interlocked.Increment(ref _count) == _minObservers)
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{
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var c = _source.Connect();
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_onConnect?.Invoke(c);
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}
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}
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return d;
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}
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}
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}
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