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.maybe;
  
  import java.util.concurrent.TimeoutException;
  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;
  import io.reactivex.rxjava3.plugins.RxJavaPlugins;
  
  /**
   * Switches to the fallback Maybe if the other Publisher signals a success or completes, or
   * signals TimeoutException if fallback is null.
   * 
   * @param <T> the main value type
   * @param <U> the other value type
   */
  public final class MaybeTimeoutPublisher<T, U> extends AbstractMaybeWithUpstream<T, T> {
  
      final Publisher<U> other;
  
      final MaybeSource<? extends T> fallback;
  
      public MaybeTimeoutPublisher(MaybeSource<T> source, Publisher<U> other, MaybeSource<? extends T> fallback) {
          super(source);
          this.other = other;
          this.fallback = fallback;
      }
  
      @Override
      protected void subscribeActual(MaybeObserver<? super T> observer) {
          TimeoutMainMaybeObserver<T, U> parent = new TimeoutMainMaybeObserver<>(observer, fallback);
          observer.onSubscribe(parent);
  
          other.subscribe(parent.other);
  
          source.subscribe(parent);
      }
  
      static final class TimeoutMainMaybeObserver<T, U>
      extends AtomicReference<Disposable>
      implements MaybeObserver<T>, Disposable {
  
          private static final long serialVersionUID = -5955289211445418871L;
  
          final MaybeObserver<? super T> downstream;
  
          final TimeoutOtherMaybeObserver<T, U> other;
  
          final MaybeSource<? extends T> fallback;
  
          final TimeoutFallbackMaybeObserver<T> otherObserver;
  
          TimeoutMainMaybeObserver(MaybeObserver<? super T> actual, MaybeSource<? extends T> fallback) {
              this.downstream = actual;
              this.other = new TimeoutOtherMaybeObserver<>(this);
              this.fallback = fallback;
              this.otherObserver = fallback != null ? new TimeoutFallbackMaybeObserver<>(actual) : null;
          }
  
          @Override
          public void dispose() {
              DisposableHelper.dispose(this);
              SubscriptionHelper.cancel(other);
              TimeoutFallbackMaybeObserver<T> oo = otherObserver;
              if (oo != null) {
                  DisposableHelper.dispose(oo);
              }
          }
  
          @Override
          public boolean isDisposed() {
              return DisposableHelper.isDisposed(get());
          }
  
          @Override
          public void onSubscribe(Disposable d) {
              DisposableHelper.setOnce(this, d);
          }
  
          @Override
          public void onSuccess(T value) {
              SubscriptionHelper.cancel(other);
              if (getAndSet(DisposableHelper.DISPOSED) != DisposableHelper.DISPOSED) {
                  downstream.onSuccess(value);
              }
          }
  
          @Override
          public void onError(Throwable e) {
              SubscriptionHelper.cancel(other);
              if (getAndSet(DisposableHelper.DISPOSED) != DisposableHelper.DISPOSED) {
                  downstream.onError(e);
              } else {
                  RxJavaPlugins.onError(e);
              }
          }
  
          @Override
          public void onComplete() {
              SubscriptionHelper.cancel(other);
              if (getAndSet(DisposableHelper.DISPOSED) != DisposableHelper.DISPOSED) {
                  downstream.onComplete();
              }
          }
  
          public void otherError(Throwable e) {
              if (DisposableHelper.dispose(this)) {
                  downstream.onError(e);
              } else {
                  RxJavaPlugins.onError(e);
              }
          }
  
          public void otherComplete() {
              if (DisposableHelper.dispose(this)) {
                  if (fallback == null) {
                      downstream.onError(new TimeoutException());
                  } else {
                      fallback.subscribe(otherObserver);
                  }
              }
          }
      }
  
      static final class TimeoutOtherMaybeObserver<T, U>
      extends AtomicReference<Subscription>
      implements FlowableSubscriber<Object> {
  
          private static final long serialVersionUID = 8663801314800248617L;
  
          final TimeoutMainMaybeObserver<T, U> parent;
  
          TimeoutOtherMaybeObserver(TimeoutMainMaybeObserver<T, U> parent) {
              this.parent = parent;
          }
  
          @Override
          public void onSubscribe(Subscription s) {
              SubscriptionHelper.setOnce(this, s, Long.MAX_VALUE);
          }
  
          @Override
          public void onNext(Object value) {
              get().cancel();
              parent.otherComplete();
          }
  
          @Override
          public void onError(Throwable e) {
              parent.otherError(e);
          }
  
          @Override
          public void onComplete() {
              parent.otherComplete();
          }
      }
  
      static final class TimeoutFallbackMaybeObserver<T>
      extends AtomicReference<Disposable>
      implements MaybeObserver<T> {
  
          private static final long serialVersionUID = 8663801314800248617L;
  
          final MaybeObserver<? super T> downstream;
  
          TimeoutFallbackMaybeObserver(MaybeObserver<? super T> downstream) {
              this.downstream = downstream;
          }
  
          @Override
          public void onSubscribe(Disposable d) {
              DisposableHelper.setOnce(this, d);
          }
  
          @Override
          public void onSuccess(T value) {
              downstream.onSuccess(value);
          }
  
          @Override
          public void onError(Throwable e) {
              downstream.onError(e);
          }
  
          @Override
          public void onComplete() {
              downstream.onComplete();
          }
      }
  }
  