<PackageReference Include="System.Reactive" Version="4.0.0" />

CombineLatest<TFirst, TSecond, TResult>

sealed class CombineLatest<TFirst, TSecond, TResult> : Producer<TResult, _<TFirst, TSecond, TResult>>
using System.Reactive.Disposables; namespace System.Reactive.Linq.ObservableImpl { internal sealed class CombineLatest<TFirst, TSecond, TResult> : Producer<TResult, CombineLatest<TFirst, TSecond, TResult>._> { internal sealed class _ : Sink<TResult> { private sealed class FirstObserver : IObserver<TFirst> { private readonly _ _parent; private readonly IDisposable _self; private SecondObserver _other; public SecondObserver Other { set { _other = value; } } public bool HasValue { get; set; } public TFirst Value { get; set; } public bool Done { get; set; } public FirstObserver(_ parent, IDisposable self) { _parent = parent; _self = self; } public void OnNext(TFirst value) { lock (_parent._gate) { HasValue = true; Value = value; if (_other.HasValue) { TResult val = default(TResult); try { val = _parent._resultSelector(value, _other.Value); } catch (Exception error) { _parent._observer.OnError(error); _parent.Dispose(); return; } _parent._observer.OnNext(val); } else if (_other.Done) { _parent._observer.OnCompleted(); _parent.Dispose(); } } } public void OnError(Exception error) { lock (_parent._gate) { _parent._observer.OnError(error); _parent.Dispose(); } } public void OnCompleted() { lock (_parent._gate) { Done = true; if (_other.Done) { _parent._observer.OnCompleted(); _parent.Dispose(); } else _self.Dispose(); } } } private sealed class SecondObserver : IObserver<TSecond> { private readonly _ _parent; private readonly IDisposable _self; private FirstObserver _other; public FirstObserver Other { set { _other = value; } } public bool HasValue { get; set; } public TSecond Value { get; set; } public bool Done { get; set; } public SecondObserver(_ parent, IDisposable self) { _parent = parent; _self = self; } public void OnNext(TSecond value) { lock (_parent._gate) { HasValue = true; Value = value; if (_other.HasValue) { TResult val = default(TResult); try { val = _parent._resultSelector(_other.Value, value); } catch (Exception error) { _parent._observer.OnError(error); _parent.Dispose(); return; } _parent._observer.OnNext(val); } else if (_other.Done) { _parent._observer.OnCompleted(); _parent.Dispose(); } } } public void OnError(Exception error) { lock (_parent._gate) { _parent._observer.OnError(error); _parent.Dispose(); } } public void OnCompleted() { lock (_parent._gate) { Done = true; if (_other.Done) { _parent._observer.OnCompleted(); _parent.Dispose(); } else _self.Dispose(); } } } private readonly Func<TFirst, TSecond, TResult> _resultSelector; private object _gate; public _(Func<TFirst, TSecond, TResult> resultSelector, IObserver<TResult> observer, IDisposable cancel) : base(observer, cancel) { _resultSelector = resultSelector; } public IDisposable Run(IObservable<TFirst> first, IObservable<TSecond> second) { _gate = new object(); SingleAssignmentDisposable singleAssignmentDisposable = new SingleAssignmentDisposable(); SingleAssignmentDisposable singleAssignmentDisposable2 = new SingleAssignmentDisposable(); FirstObserver firstObserver = new FirstObserver(this, singleAssignmentDisposable); SecondObserver secondObserver2 = firstObserver.Other = new SecondObserver(this, singleAssignmentDisposable2); secondObserver2.Other = firstObserver; singleAssignmentDisposable.Disposable = ObservableExtensions.SubscribeSafe<TFirst>(first, (IObserver<TFirst>)firstObserver); singleAssignmentDisposable2.Disposable = ObservableExtensions.SubscribeSafe<TSecond>(second, (IObserver<TSecond>)secondObserver2); return StableCompositeDisposable.Create(singleAssignmentDisposable, singleAssignmentDisposable2); } } private readonly IObservable<TFirst> _first; private readonly IObservable<TSecond> _second; private readonly Func<TFirst, TSecond, TResult> _resultSelector; public CombineLatest(IObservable<TFirst> first, IObservable<TSecond> second, Func<TFirst, TSecond, TResult> resultSelector) { _first = first; _second = second; _resultSelector = resultSelector; } protected override _ CreateSink(IObserver<TResult> observer, IDisposable cancel) { return new _(_resultSelector, observer, cancel); } protected override IDisposable Run(_ sink) { return sink.Run(_first, _second); } } }