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.parallel;
  
  import org.reactivestreams.*;
  
  import io.reactivex.rxjava3.core.FlowableSubscriber;
  import io.reactivex.rxjava3.exceptions.*;
  import io.reactivex.rxjava3.functions.*;
  import io.reactivex.rxjava3.internal.subscriptions.*;
  import io.reactivex.rxjava3.parallel.ParallelFlowable;
  import io.reactivex.rxjava3.plugins.RxJavaPlugins;
  
  import java.util.Objects;
  
  /**
   * Execute a Consumer in each 'rail' for the current element passing through.
   *
   * @param <T> the value type
   */
  public final class ParallelPeek<T> extends ParallelFlowable<T> {
  
      final ParallelFlowable<T> source;
  
      final Consumer<? super T> onNext;
      final Consumer<? super T> onAfterNext;
      final Consumer<? super Throwable> onError;
      final Action onComplete;
      final Action onAfterTerminated;
      final Consumer<? super Subscription> onSubscribe;
      final LongConsumer onRequest;
      final Action onCancel;
  
      public ParallelPeek(ParallelFlowable<T> source,
              Consumer<? super T> onNext,
              Consumer<? super T> onAfterNext,
              Consumer<? super Throwable> onError,
              Action onComplete,
              Action onAfterTerminated,
              Consumer<? super Subscription> onSubscribe,
              LongConsumer onRequest,
              Action onCancel
      ) {
          this.source = source;
  
          this.onNext = Objects.requireNonNull(onNext, "onNext is null");
          this.onAfterNext = Objects.requireNonNull(onAfterNext, "onAfterNext is null");
          this.onError = Objects.requireNonNull(onError, "onError is null");
          this.onComplete = Objects.requireNonNull(onComplete, "onComplete is null");
          this.onAfterTerminated = Objects.requireNonNull(onAfterTerminated, "onAfterTerminated is null");
          this.onSubscribe = Objects.requireNonNull(onSubscribe, "onSubscribe is null");
          this.onRequest = Objects.requireNonNull(onRequest, "onRequest is null");
          this.onCancel = Objects.requireNonNull(onCancel, "onCancel is null");
      }
  
      @Override
      public void subscribe(Subscriber<? super T>[] subscribers) {
          subscribers = RxJavaPlugins.onSubscribe(this, subscribers);
  
          if (!validate(subscribers)) {
              return;
          }
  
          int n = subscribers.length;
          @SuppressWarnings("unchecked")
          Subscriber<? super T>[] parents = new Subscriber[n];
  
          for (int i = 0; i < n; i++) {
              parents[i] = new ParallelPeekSubscriber<>(subscribers[i], this);
          }
  
          source.subscribe(parents);
      }
  
      @Override
      public int parallelism() {
          return source.parallelism();
      }
  
      static final class ParallelPeekSubscriber<T> implements FlowableSubscriber<T>, Subscription {
  
          final Subscriber<? super T> downstream;
  
          final ParallelPeek<T> parent;
  
          Subscription upstream;
  
          boolean done;
  
          ParallelPeekSubscriber(Subscriber<? super T> actual, ParallelPeek<T> parent) {
              this.downstream = actual;
              this.parent = parent;
          }
  
          @Override
          public void request(long n) {
              try {
                  parent.onRequest.accept(n);
              } catch (Throwable ex) {
                  Exceptions.throwIfFatal(ex);
                  RxJavaPlugins.onError(ex);
              }
              upstream.request(n);
          }
  
          @Override
          public void cancel() {
              try {
                  parent.onCancel.run();
              } catch (Throwable ex) {
                  Exceptions.throwIfFatal(ex);
                  RxJavaPlugins.onError(ex);
              }
              upstream.cancel();
          }
  
          @Override
          public void onSubscribe(Subscription s) {
              if (SubscriptionHelper.validate(this.upstream, s)) {
                  this.upstream = s;
  
                  try {
                      parent.onSubscribe.accept(s);
                  } catch (Throwable ex) {
                      Exceptions.throwIfFatal(ex);
                      s.cancel();
                      downstream.onSubscribe(EmptySubscription.INSTANCE);
                      onError(ex);
                      return;
                  }
  
                  downstream.onSubscribe(this);
              }
          }
  
          @Override
          public void onNext(T t) {
              if (!done) {
                  try {
                      parent.onNext.accept(t);
                  } catch (Throwable ex) {
                      Exceptions.throwIfFatal(ex);
                      onError(ex);
                      return;
                  }
  
                  downstream.onNext(t);
  
                  try {
                      parent.onAfterNext.accept(t);
                  } catch (Throwable ex) {
                      Exceptions.throwIfFatal(ex);
                      onError(ex);
                  }
              }
          }
  
          @Override
          public void onError(Throwable t) {
              if (done) {
                  RxJavaPlugins.onError(t);
                  return;
              }
              done = true;
  
              try {
                  parent.onError.accept(t);
              } catch (Throwable ex) {
                  Exceptions.throwIfFatal(ex);
                  t = new CompositeException(t, ex);
              }
              downstream.onError(t);
  
              try {
                  parent.onAfterTerminated.run();
              } catch (Throwable ex) {
                  Exceptions.throwIfFatal(ex);
                  RxJavaPlugins.onError(ex);
              }
          }
  
          @Override
          public void onComplete() {
              if (!done) {
                  done = true;
                  try {
                      parent.onComplete.run();
                  } catch (Throwable ex) {
                      Exceptions.throwIfFatal(ex);
                      downstream.onError(ex);
                      return;
                  }
                  downstream.onComplete();
  
                  try {
                      parent.onAfterTerminated.run();
                  } catch (Throwable ex) {
                      Exceptions.throwIfFatal(ex);
                      RxJavaPlugins.onError(ex);
                  }
              }
          }
      }
  }
  