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.TimeUnit;
  
  import io.reactivex.rxjava3.annotations.NonNull;
  import io.reactivex.rxjava3.core.*;
  import io.reactivex.rxjava3.disposables.Disposable;
  import io.reactivex.rxjava3.internal.disposables.DisposableHelper;
  import io.reactivex.rxjava3.schedulers.Timed;
  
  /**
   * Measures the time between subscription and the success item emission
   * from the upstream and emits this as a {@link Timed} success value.
   * @param <T> the element type of the sequence
   * @since 3.0.0
   */
  public final class MaybeTimeInterval<T> extends Maybe<Timed<T>> {
  
      final MaybeSource<T> source;
  
      final TimeUnit unit;
  
      final Scheduler scheduler;
  
      final boolean start;
  
      public MaybeTimeInterval(MaybeSource<T> source, TimeUnit unit, Scheduler scheduler, boolean start) {
          this.source = source;
          this.unit = unit;
          this.scheduler = scheduler;
          this.start = start;
      }
  
      @Override
      protected void subscribeActual(@NonNull MaybeObserver<? super @NonNull Timed<T>> observer) {
          source.subscribe(new TimeIntervalMaybeObserver<>(observer, unit, scheduler, start));
      }
  
      static final class TimeIntervalMaybeObserver<T> implements MaybeObserver<T>, Disposable {
  
          final MaybeObserver<? super Timed<T>> downstream;
  
          final TimeUnit unit;
  
          final Scheduler scheduler;
  
          final long startTime;
  
          Disposable upstream;
  
          TimeIntervalMaybeObserver(MaybeObserver<? super Timed<T>> downstream, TimeUnit unit, Scheduler scheduler, boolean start) {
              this.downstream = downstream;
              this.unit = unit;
              this.scheduler = scheduler;
              this.startTime = start ? scheduler.now(unit) : 0L;
          }
  
          @Override
          public void onSubscribe(@NonNull Disposable d) {
              if (DisposableHelper.validate(this.upstream, d)) {
                  this.upstream = d;
  
                  downstream.onSubscribe(this);
              }
          }
  
          @Override
          public void onSuccess(@NonNull T t) {
              downstream.onSuccess(new Timed<>(t, scheduler.now(unit) - startTime, unit));
          }
  
          @Override
          public void onError(@NonNull Throwable e) {
              downstream.onError(e);
          }
  
          @Override
          public void onComplete() {
              downstream.onComplete();
          }
  
          @Override
          public void dispose() {
              upstream.dispose();
          }
  
          @Override
          public boolean isDisposed() {
              return upstream.isDisposed();
          }
      }
  }
  