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.internal.subscriptions.*;
  
  public final class FlowableCount<T> extends AbstractFlowableWithUpstream<T, Long> {
  
      public FlowableCount(Flowable<T> source) {
          super(source);
      }
  
      @Override
      protected void subscribeActual(Subscriber<? super Long> s) {
          source.subscribe(new CountSubscriber(s));
      }
  
      static final class CountSubscriber extends DeferredScalarSubscription<Long>
      implements FlowableSubscriber<Object> {
  
          private static final long serialVersionUID = 4973004223787171406L;
  
          Subscription upstream;
  
          long count;
  
          CountSubscriber(Subscriber<? super Long> downstream) {
              super(downstream);
          }
  
          @Override
          public void onSubscribe(Subscription s) {
              if (SubscriptionHelper.validate(this.upstream, s)) {
                  this.upstream = s;
                  downstream.onSubscribe(this);
                  s.request(Long.MAX_VALUE);
              }
          }
  
          @Override
          public void onNext(Object t) {
              count++;
          }
  
          @Override
          public void onError(Throwable t) {
              downstream.onError(t);
          }
  
          @Override
          public void onComplete() {
              complete(count);
          }
  
          @Override
          public void cancel() {
              super.cancel();
              upstream.cancel();
          }
      }
  }
  