code: /*
   * Copyright (c) 2016-present, RxJava Contributors.
   *
   * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
   * compliance with the License. You may obtain a copy of the License at
   *
   * http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software distributed under the License is
   * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
   * the License for the specific language governing permissions and limitations under the License.
   */
  
  package io.reactivex.rxjava3.internal.operators.flowable;
  
  import java.util.Objects;
  import java.util.concurrent.atomic.*;
  
  import org.reactivestreams.*;
  
  import io.reactivex.rxjava3.core.*;
  import io.reactivex.rxjava3.exceptions.Exceptions;
  import io.reactivex.rxjava3.functions.Function;
  import io.reactivex.rxjava3.internal.subscriptions.*;
  import io.reactivex.rxjava3.processors.*;
  import io.reactivex.rxjava3.subscribers.SerializedSubscriber;
  
  public final class FlowableRepeatWhen<T> extends AbstractFlowableWithUpstream<T, T> {
      final Function<? super Flowable<Object>, ? extends Publisher<?>> handler;
  
      public FlowableRepeatWhen(Flowable<T> source,
              Function<? super Flowable<Object>, ? extends Publisher<?>> handler) {
          super(source);
          this.handler = handler;
      }
  
      @Override
      public void subscribeActual(Subscriber<? super T> s) {
  
          SerializedSubscriber<T> z = new SerializedSubscriber<>(s);
  
          FlowableProcessor<Object> processor = UnicastProcessor.create(8).toSerialized();
  
          Publisher<?> when;
  
          try {
              when = Objects.requireNonNull(handler.apply(processor), "handler returned a null Publisher");
          } catch (Throwable ex) {
              Exceptions.throwIfFatal(ex);
              EmptySubscription.error(ex, s);
              return;
          }
  
          WhenReceiver<T, Object> receiver = new WhenReceiver<>(source);
  
          RepeatWhenSubscriber<T> subscriber = new RepeatWhenSubscriber<>(z, processor, receiver);
  
          receiver.subscriber = subscriber;
  
          s.onSubscribe(subscriber);
  
          when.subscribe(receiver);
  
          receiver.onNext(0);
      }
  
      static final class WhenReceiver<T, U>
      extends AtomicInteger
      implements FlowableSubscriber<Object>, Subscription {
  
          private static final long serialVersionUID = 2827772011130406689L;
  
          final Publisher<T> source;
  
          final AtomicReference<Subscription> upstream;
  
          final AtomicLong requested;
  
          WhenSourceSubscriber<T, U> subscriber;
  
          WhenReceiver(Publisher<T> source) {
              this.source = source;
              this.upstream = new AtomicReference<>();
              this.requested = new AtomicLong();
          }
  
          @Override
          public void onSubscribe(Subscription s) {
              SubscriptionHelper.deferredSetOnce(upstream, requested, s);
          }
  
          @Override
          public void onNext(Object t) {
              if (getAndIncrement() == 0) {
                  for (;;) {
                      if (upstream.get() == SubscriptionHelper.CANCELLED) {
                          return;
                      }
  
                      source.subscribe(subscriber);
  
                      if (decrementAndGet() == 0) {
                          break;
                      }
                  }
              }
          }
  
          @Override
          public void onError(Throwable t) {
              subscriber.cancel();
              subscriber.downstream.onError(t);
          }
  
          @Override
          public void onComplete() {
              subscriber.cancel();
              subscriber.downstream.onComplete();
          }
  
          @Override
          public void request(long n) {
              SubscriptionHelper.deferredRequest(upstream, requested, n);
          }
  
          @Override
          public void cancel() {
              SubscriptionHelper.cancel(upstream);
          }
      }
  
      abstract static class WhenSourceSubscriber<T, U> extends SubscriptionArbiter implements FlowableSubscriber<T> {
  
          private static final long serialVersionUID = -5604623027276966720L;
  
          protected final Subscriber<? super T> downstream;
  
          protected final FlowableProcessor<U> processor;
  
          protected final Subscription receiver;
  
          private long produced;
  
          WhenSourceSubscriber(Subscriber<? super T> actual, FlowableProcessor<U> processor,
                  Subscription receiver) {
              super(false);
              this.downstream = actual;
              this.processor = processor;
              this.receiver = receiver;
          }
  
          @Override
          public final void onSubscribe(Subscription s) {
              setSubscription(s);
          }
  
          @Override
          public final void onNext(T t) {
              produced++;
              downstream.onNext(t);
          }
  
          protected final void again(U signal) {
              setSubscription(EmptySubscription.INSTANCE);
              long p = produced;
              if (p != 0L) {
                  produced = 0L;
                  produced(p);
              }
              receiver.request(1);
              processor.onNext(signal);
          }
  
          @Override
          public final void cancel() {
              super.cancel();
              receiver.cancel();
          }
      }
  
      static final class RepeatWhenSubscriber<T> extends WhenSourceSubscriber<T, Object> {
  
          private static final long serialVersionUID = -2680129890138081029L;
  
          RepeatWhenSubscriber(Subscriber<? super T> actual, FlowableProcessor<Object> processor,
                  Subscription receiver) {
              super(actual, processor, receiver);
          }
  
          @Override
          public void onError(Throwable t) {
              receiver.cancel();
              downstream.onError(t);
          }
  
          @Override
          public void onComplete() {
              again(0);
          }
      }
  }
  