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.annotations.Nullable;
  import io.reactivex.rxjava3.core.*;
  import io.reactivex.rxjava3.exceptions.Exceptions;
  import io.reactivex.rxjava3.functions.Action;
  import io.reactivex.rxjava3.internal.subscriptions.*;
  import io.reactivex.rxjava3.operators.ConditionalSubscriber;
  import io.reactivex.rxjava3.operators.QueueSubscription;
  import io.reactivex.rxjava3.plugins.RxJavaPlugins;
  
  /**
   * Execute an action after an onError, onComplete or a cancel event.
   * <p>History: 2.0.1 - experimental
   * @param <T> the value type
   * @since 2.1
   */
  public final class FlowableDoFinally<T> extends AbstractFlowableWithUpstream<T, T> {
  
      final Action onFinally;
  
      public FlowableDoFinally(Flowable<T> source, Action onFinally) {
          super(source);
          this.onFinally = onFinally;
      }
  
      @Override
      protected void subscribeActual(Subscriber<? super T> s) {
          if (s instanceof ConditionalSubscriber) {
              source.subscribe(new DoFinallyConditionalSubscriber<>((ConditionalSubscriber<? super T>) s, onFinally));
          } else {
              source.subscribe(new DoFinallySubscriber<>(s, onFinally));
          }
      }
  
      static final class DoFinallySubscriber<T> extends BasicIntQueueSubscription<T> implements FlowableSubscriber<T> {
  
          private static final long serialVersionUID = 4109457741734051389L;
  
          final Subscriber<? super T> downstream;
  
          final Action onFinally;
  
          Subscription upstream;
  
          QueueSubscription<T> qs;
  
          boolean syncFused;
  
          DoFinallySubscriber(Subscriber<? super T> actual, Action onFinally) {
              this.downstream = actual;
              this.onFinally = onFinally;
          }
  
          @SuppressWarnings("unchecked")
          @Override
          public void onSubscribe(Subscription s) {
              if (SubscriptionHelper.validate(this.upstream, s)) {
                  this.upstream = s;
                  if (s instanceof QueueSubscription) {
                      this.qs = (QueueSubscription<T>)s;
                  }
  
                  downstream.onSubscribe(this);
              }
          }
  
          @Override
          public void onNext(T t) {
              downstream.onNext(t);
          }
  
          @Override
          public void onError(Throwable t) {
              downstream.onError(t);
              runFinally();
          }
  
          @Override
          public void onComplete() {
              downstream.onComplete();
              runFinally();
          }
  
          @Override
          public void cancel() {
              upstream.cancel();
              runFinally();
          }
  
          @Override
          public void request(long n) {
              upstream.request(n);
          }
  
          @Override
          public int requestFusion(int mode) {
              QueueSubscription<T> qs = this.qs;
              if (qs != null && (mode & BOUNDARY) == 0) {
                  int m = qs.requestFusion(mode);
                  if (m != NONE) {
                      syncFused = m == SYNC;
                  }
                  return m;
              }
              return NONE;
          }
  
          @Override
          public void clear() {
              qs.clear();
          }
  
          @Override
          public boolean isEmpty() {
              return qs.isEmpty();
          }
  
          @Nullable
          @Override
          public T poll() throws Throwable {
              T v = qs.poll();
              if (v == null && syncFused) {
                  runFinally();
              }
              return v;
          }
  
          void runFinally() {
              if (compareAndSet(0, 1)) {
                  try {
                      onFinally.run();
                  } catch (Throwable ex) {
                      Exceptions.throwIfFatal(ex);
                      RxJavaPlugins.onError(ex);
                  }
              }
          }
      }
  
      static final class DoFinallyConditionalSubscriber<T> extends BasicIntQueueSubscription<T> implements ConditionalSubscriber<T> {
  
          private static final long serialVersionUID = 4109457741734051389L;
  
          final ConditionalSubscriber<? super T> downstream;
  
          final Action onFinally;
  
          Subscription upstream;
  
          QueueSubscription<T> qs;
  
          boolean syncFused;
  
          DoFinallyConditionalSubscriber(ConditionalSubscriber<? super T> actual, Action onFinally) {
              this.downstream = actual;
              this.onFinally = onFinally;
          }
  
          @SuppressWarnings("unchecked")
          @Override
          public void onSubscribe(Subscription s) {
              if (SubscriptionHelper.validate(this.upstream, s)) {
                  this.upstream = s;
                  if (s instanceof QueueSubscription) {
                      this.qs = (QueueSubscription<T>)s;
                  }
  
                  downstream.onSubscribe(this);
              }
          }
  
          @Override
          public void onNext(T t) {
              downstream.onNext(t);
          }
  
          @Override
          public boolean tryOnNext(T t) {
              return downstream.tryOnNext(t);
          }
  
          @Override
          public void onError(Throwable t) {
              downstream.onError(t);
              runFinally();
          }
  
          @Override
          public void onComplete() {
              downstream.onComplete();
              runFinally();
          }
  
          @Override
          public void cancel() {
              upstream.cancel();
              runFinally();
          }
  
          @Override
          public void request(long n) {
              upstream.request(n);
          }
  
          @Override
          public int requestFusion(int mode) {
              QueueSubscription<T> qs = this.qs;
              if (qs != null && (mode & BOUNDARY) == 0) {
                  int m = qs.requestFusion(mode);
                  if (m != NONE) {
                      syncFused = m == SYNC;
                  }
                  return m;
              }
              return NONE;
          }
  
          @Override
          public void clear() {
              qs.clear();
          }
  
          @Override
          public boolean isEmpty() {
              return qs.isEmpty();
          }
  
          @Nullable
          @Override
          public T poll() throws Throwable {
              T v = qs.poll();
              if (v == null && syncFused) {
                  runFinally();
              }
              return v;
          }
  
          void runFinally() {
              if (compareAndSet(0, 1)) {
                  try {
                      onFinally.run();
                  } catch (Throwable ex) {
                      Exceptions.throwIfFatal(ex);
                      RxJavaPlugins.onError(ex);
                  }
              }
          }
      }
  }
  