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.concurrent.atomic.AtomicReference;
  
  import org.reactivestreams.*;
  
  import io.reactivex.rxjava3.core.*;
  import io.reactivex.rxjava3.disposables.Disposable;
  import io.reactivex.rxjava3.internal.disposables.DisposableHelper;
  import io.reactivex.rxjava3.internal.subscriptions.SubscriptionHelper;
  
  /**
   * Subscribe to a main Flowable first, then when it completes normally, subscribe to a Completable
   * and terminate when it terminates.
   * <p>History: 2.1.10 - experimental
   * @param <T> the element type of the main source and output type
   * @since 2.2
   */
  public final class FlowableConcatWithCompletable<T> extends AbstractFlowableWithUpstream<T, T> {
  
      final CompletableSource other;
  
      public FlowableConcatWithCompletable(Flowable<T> source, CompletableSource other) {
          super(source);
          this.other = other;
      }
  
      @Override
      protected void subscribeActual(Subscriber<? super T> s) {
          source.subscribe(new ConcatWithSubscriber<>(s, other));
      }
  
      static final class ConcatWithSubscriber<T>
      extends AtomicReference<Disposable>
      implements FlowableSubscriber<T>, CompletableObserver, Subscription {
  
          private static final long serialVersionUID = -7346385463600070225L;
  
          final Subscriber<? super T> downstream;
  
          Subscription upstream;
  
          CompletableSource other;
  
          boolean inCompletable;
  
          ConcatWithSubscriber(Subscriber<? super T> actual, CompletableSource other) {
              this.downstream = actual;
              this.other = other;
          }
  
          @Override
          public void onSubscribe(Subscription s) {
              if (SubscriptionHelper.validate(upstream, s)) {
                  this.upstream = s;
                  downstream.onSubscribe(this);
              }
          }
  
          @Override
          public void onSubscribe(Disposable d) {
              DisposableHelper.setOnce(this, d);
          }
  
          @Override
          public void onNext(T t) {
              downstream.onNext(t);
          }
  
          @Override
          public void onError(Throwable t) {
              downstream.onError(t);
          }
  
          @Override
          public void onComplete() {
              if (inCompletable) {
                  downstream.onComplete();
              } else {
                  inCompletable = true;
                  upstream = SubscriptionHelper.CANCELLED;
                  CompletableSource cs = other;
                  other = null;
                  cs.subscribe(this);
              }
          }
  
          @Override
          public void request(long n) {
              upstream.request(n);
          }
  
          @Override
          public void cancel() {
              upstream.cancel();
              DisposableHelper.dispose(this);
          }
      }
  }
  