38 lines
1.6 KiB
C#
38 lines
1.6 KiB
C#
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using System.Reactive.Concurrency;
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using System.Reactive.Linq;
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namespace StarsAssistant.Helpers;
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public static class RxExtensions
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{
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/// <summary>
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/// Wrap an observerble to throttle the incoming changes into a given window. Will delay and collect
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/// any events fired until the minimum inactivity period has elapsed without events.
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/// </summary>
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/// <remarks>Curtesy of https://endjin.com/blog/2024/05/observe-file-system-changes-with-rx-dotnet</remarks>
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/// <typeparam name="T">The original type being observed</typeparam>
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/// <param name="src">The source observable to throttle.</param>
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/// <param name="minimumInactivityPeriod">The minimum inactivity period to wait before propagating.</param>
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/// <param name="scheduler">The scheduler to use, defaults to the default scheduler.</param>
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/// <returns>Wrapped observable.</returns>
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public static IObservable<IList<T>> Quiescent<T>(
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this IObservable<T> src,
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TimeSpan minimumInactivityPeriod,
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IScheduler? scheduler = null)
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{
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IScheduler realScheduler = scheduler ?? DefaultScheduler.Instance;
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IObservable<int> onoffs =
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from _ in src
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from delta in
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Observable.Return(1, realScheduler)
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.Concat(Observable.Return(-1, realScheduler)
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.Delay(minimumInactivityPeriod, realScheduler))
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select delta;
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IObservable<int> outstanding = onoffs.Scan(0, (total, delta) => total + delta);
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IObservable<int> zeroCrossings = outstanding.Where(total => total == 0);
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return src.Buffer(zeroCrossings);
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}
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}
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