<PackageReference Include="System.Reactive" Version="4.3.1" />

TakeLast<TSource>

static class TakeLast<TSource>
using System.Collections.Generic; using System.Reactive.Concurrency; using System.Reactive.Disposables; namespace System.Reactive.Linq.ObservableImpl { internal static class TakeLast<TSource> { internal sealed class Count : Producer<TSource, Count._> { internal sealed class _ : IdentitySink<TSource> { private readonly int _count; private readonly IScheduler _loopScheduler; private readonly Queue<TSource> _queue; private IDisposable _loopDisposable; public _(Count parent, IObserver<TSource> observer) : base(observer) { _count = parent._count; _loopScheduler = parent._loopScheduler; _queue = new Queue<TSource>(); } protected override void Dispose(bool disposing) { if (disposing) Disposable.TryDispose(ref _loopDisposable); base.Dispose(disposing); } public override void OnNext(TSource value) { _queue.Enqueue(value); if (_queue.Count > _count) _queue.Dequeue(); } public override void OnCompleted() { DisposeUpstream(); ISchedulerLongRunning schedulerLongRunning = _loopScheduler.AsLongRunning(); if (schedulerLongRunning != null) Disposable.SetSingle(ref _loopDisposable, schedulerLongRunning.ScheduleLongRunning<_>(this, (Action<_, ICancelable>)delegate(_ this, ICancelable c) { this.Loop(c); })); else { IDisposable value = _loopScheduler.Schedule<_>(this, (Func<IScheduler, _, IDisposable>)((IScheduler innerScheduler, _ this) => this.LoopRec(innerScheduler))); Disposable.TrySetSingle(ref _loopDisposable, value); } } private IDisposable LoopRec(IScheduler scheduler) { if (_queue.Count > 0) { ForwardOnNext(_queue.Dequeue()); IDisposable value = scheduler.Schedule<_>(this, (Func<IScheduler, _, IDisposable>)((IScheduler innerScheduler, _ this) => this.LoopRec(innerScheduler))); Disposable.TrySetMultiple(ref _loopDisposable, value); } else ForwardOnCompleted(); return Disposable.Empty; } private void Loop(ICancelable cancel) { int num = _queue.Count; while (!cancel.IsDisposed) { if (num == 0) { ForwardOnCompleted(); break; } ForwardOnNext(_queue.Dequeue()); num--; } Dispose(); } } private readonly IObservable<TSource> _source; private readonly int _count; private readonly IScheduler _loopScheduler; public Count(IObservable<TSource> source, int count, IScheduler loopScheduler) { _source = source; _count = count; _loopScheduler = loopScheduler; } protected override _ CreateSink(IObserver<TSource> observer) { return new _(this, observer); } protected override void Run(_ sink) { sink.Run(_source); } } internal sealed class Time : Producer<TSource, Time._> { internal sealed class _ : IdentitySink<TSource> { private readonly TimeSpan _duration; private readonly IScheduler _loopScheduler; private readonly Queue<System.Reactive.TimeInterval<TSource>> _queue; private IDisposable _loopDisposable; private IStopwatch _watch; public _(Time parent, IObserver<TSource> observer) : base(observer) { _duration = parent._duration; _loopScheduler = parent._loopScheduler; _queue = new Queue<System.Reactive.TimeInterval<TSource>>(); } public void Run(IObservable<TSource> source, IScheduler scheduler) { _watch = scheduler.StartStopwatch(); Run(source); } protected override void Dispose(bool disposing) { if (disposing) Disposable.TryDispose(ref _loopDisposable); base.Dispose(disposing); } public override void OnNext(TSource value) { TimeSpan elapsed = _watch.Elapsed; _queue.Enqueue(new System.Reactive.TimeInterval<TSource>(value, elapsed)); Trim(elapsed); } public override void OnCompleted() { DisposeUpstream(); TimeSpan elapsed = _watch.Elapsed; Trim(elapsed); ISchedulerLongRunning schedulerLongRunning = _loopScheduler.AsLongRunning(); if (schedulerLongRunning != null) Disposable.SetSingle(ref _loopDisposable, schedulerLongRunning.ScheduleLongRunning<_>(this, (Action<_, ICancelable>)delegate(_ this, ICancelable c) { this.Loop(c); })); else { IDisposable value = _loopScheduler.Schedule<_>(this, (Func<IScheduler, _, IDisposable>)((IScheduler innerScheduler, _ this) => this.LoopRec(innerScheduler))); Disposable.TrySetSingle(ref _loopDisposable, value); } } private IDisposable LoopRec(IScheduler scheduler) { if (_queue.Count > 0) { ForwardOnNext(_queue.Dequeue().Value); IDisposable value = scheduler.Schedule<_>(this, (Func<IScheduler, _, IDisposable>)((IScheduler innerScheduler, _ this) => this.LoopRec(innerScheduler))); Disposable.TrySetMultiple(ref _loopDisposable, value); } else ForwardOnCompleted(); return Disposable.Empty; } private void Loop(ICancelable cancel) { int num = _queue.Count; while (!cancel.IsDisposed) { if (num == 0) { ForwardOnCompleted(); break; } ForwardOnNext(_queue.Dequeue().Value); num--; } Dispose(); } private void Trim(TimeSpan now) { while (_queue.Count > 0 && now - _queue.Peek().Interval >= _duration) { _queue.Dequeue(); } } } private readonly IObservable<TSource> _source; private readonly TimeSpan _duration; private readonly IScheduler _scheduler; private readonly IScheduler _loopScheduler; public Time(IObservable<TSource> source, TimeSpan duration, IScheduler scheduler, IScheduler loopScheduler) { _source = source; _duration = duration; _scheduler = scheduler; _loopScheduler = loopScheduler; } protected override _ CreateSink(IObserver<TSource> observer) { return new _(this, observer); } protected override void Run(_ sink) { sink.Run(_source, _scheduler); } } } }