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 org.reactivestreams.*;
  
  import io.reactivex.rxjava3.core.*;
  import io.reactivex.rxjava3.disposables.Disposable;
  
  public final class FlowableFromObservable<T> extends Flowable<T> {
  
      private final ObservableSource<T> upstream;
  
      public FlowableFromObservable(ObservableSource<T> upstream) {
          this.upstream = upstream;
      }
  
      @Override
      protected void subscribeActual(Subscriber<? super T> s) {
          upstream.subscribe(new SubscriberObserver<>(s));
      }
  
      static final class SubscriberObserver<T> implements Observer<T>, Subscription {
  
          final Subscriber<? super T> downstream;
  
          Disposable upstream;
  
          SubscriberObserver(Subscriber<? super T> s) {
              this.downstream = s;
          }
  
          @Override
          public void onComplete() {
              downstream.onComplete();
          }
  
          @Override
          public void onError(Throwable e) {
              downstream.onError(e);
          }
  
          @Override
          public void onNext(T value) {
              downstream.onNext(value);
          }
  
          @Override
          public void onSubscribe(Disposable d) {
              this.upstream = d;
              downstream.onSubscribe(this);
          }
  
          @Override public void cancel() {
              upstream.dispose();
          }
  
          @Override
          public void request(long n) {
              // no backpressure so nothing we can do about this
          }
      }
  }
  