using System.Collections.Generic; namespace System.Reactive.Linq.ObservableImpl { internal sealed class DoWhile<TSource> : Producer<TSource, DoWhile<TSource>._>, IConcatenatable<TSource> { internal sealed class _ : ConcatSink<TSource> { public _(IObserver<TSource> observer) : base(observer) { } } private readonly IObservable<TSource> _source; private readonly Func<bool> _condition; public DoWhile(IObservable<TSource> source, Func<bool> condition) { _condition = condition; _source = source; } protected override _ CreateSink(IObserver<TSource> observer) { return new _(observer); } protected override void Run(_ sink) { sink.Run(GetSources()); } public IEnumerable<IObservable<TSource>> GetSources() { yield return this._source; while (this._condition()) { yield return this._source; } } } }