https://github.com/ReactiveX/RxJava: Reactive Extensions for Java
  • David Karnok 
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.

/**
 * 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.internal.operators.flowable;

import java.util.concurrent.TimeoutException;
import java.util.concurrent.atomic.*;

import org.reactivestreams.*;

import io.reactivex.*;
import io.reactivex.disposables.Disposable;
import io.reactivex.exceptions.Exceptions;
import io.reactivex.functions.Function;
import io.reactivex.internal.disposables.SequentialDisposable;
import io.reactivex.internal.functions.ObjectHelper;
import io.reactivex.internal.operators.flowable.FlowableTimeoutTimed.TimeoutSupport;
import io.reactivex.internal.subscriptions.*;
import io.reactivex.plugins.RxJavaPlugins;

public final class FlowableTimeout<T, U, V> extends AbstractFlowableWithUpstream<T, T> {
    final Publisher<U> firstTimeoutIndicator;
    final Function<? super T, ? extends Publisher<V>> itemTimeoutIndicator;
    final Publisher<? extends T> other;

    public FlowableTimeout(
            Flowable<T> source,
            Publisher<U> firstTimeoutIndicator,
            Function<? super T, ? extends Publisher<V>> itemTimeoutIndicator,
            Publisher<? extends T> other) {
        super(source);
        this.firstTimeoutIndicator = firstTimeoutIndicator;
        this.itemTimeoutIndicator = itemTimeoutIndicator;
        this.other = other;
    }

    @Override
    protected void subscribeActual(Subscriber<? super T> s) {
        if (other == null) {
            TimeoutSubscriber<T> parent = new TimeoutSubscriber<T>(s, itemTimeoutIndicator);
            s.onSubscribe(parent);
            parent.startFirstTimeout(firstTimeoutIndicator);
            source.subscribe(parent);
        } else {
            TimeoutFallbackSubscriber<T> parent = new TimeoutFallbackSubscriber<T>(s, itemTimeoutIndicator, other);
            s.onSubscribe(parent);
            parent.startFirstTimeout(firstTimeoutIndicator);
            source.subscribe(parent);
        }
    }

    interface TimeoutSelectorSupport extends TimeoutSupport {
        void onTimeoutError(long idx, Throwable ex);
    }

    static final class TimeoutSubscriber<T> extends AtomicLong
    implements FlowableSubscriber<T>, Subscription, TimeoutSelectorSupport {

        private static final long serialVersionUID = 3764492702657003550L;

        final Subscriber<? super T> downstream;

        final Function<? super T, ? extends Publisher<?>> itemTimeoutIndicator;

        final SequentialDisposable task;

        final AtomicReference<Subscription> upstream;

        final AtomicLong requested;

        TimeoutSubscriber(Subscriber<? super T> actual, Function<? super T, ? extends Publisher<?>> itemTimeoutIndicator) {
            this.downstream = actual;
            this.itemTimeoutIndicator = itemTimeoutIndicator;
            this.task = new SequentialDisposable();
            this.upstream = new AtomicReference<Subscription>();
            this.requested = new AtomicLong();
        }

        @Override
        public void onSubscribe(Subscription s) {
            SubscriptionHelper.deferredSetOnce(upstream, requested, s);
        }

        @Override
        public void onNext(T t) {
            long idx = get();
            if (idx == Long.MAX_VALUE || !compareAndSet(idx, idx + 1)) {
                return;
            }

            Disposable d = task.get();
            if (d != null) {
                d.dispose();
            }

            downstream.onNext(t);

            Publisher<?> itemTimeoutPublisher;

            try {
                itemTimeoutPublisher = ObjectHelper.requireNonNull(
                        itemTimeoutIndicator.apply(t),
                        "The itemTimeoutIndicator returned a null Publisher.");
            } catch (Throwable ex) {
                Exceptions.throwIfFatal(ex);
                upstream.get().cancel();
                getAndSet(Long.MAX_VALUE);
                downstream.onError(ex);
                return;
            }

            TimeoutConsumer consumer = new TimeoutConsumer(idx + 1, this);
            if (task.replace(consumer)) {
                itemTimeoutPublisher.subscribe(consumer);
            }
        }

        void startFirstTimeout(Publisher<?> firstTimeoutIndicator) {
            if (firstTimeoutIndicator != null) {
                TimeoutConsumer consumer = new TimeoutConsumer(0L, this);
                if (task.replace(consumer)) {
                    firstTimeoutIndicator.subscribe(consumer);
                }
            }
        }

        @Override
        public void onError(Throwable t) {
            if (getAndSet(Long.MAX_VALUE) != Long.MAX_VALUE) {
                task.dispose();

                downstream.onError(t);
            } else {
                RxJavaPlugins.onError(t);
            }
        }

        @Override
        public void onComplete() {
            if (getAndSet(Long.MAX_VALUE) != Long.MAX_VALUE) {
                task.dispose();

                downstream.onComplete();
            }
        }

        @Override
        public void onTimeout(long idx) {
            if (compareAndSet(idx, Long.MAX_VALUE)) {
                SubscriptionHelper.cancel(upstream);

                downstream.onError(new TimeoutException());
            }
        }

        @Override
        public void onTimeoutError(long idx, Throwable ex) {
            if (compareAndSet(idx, Long.MAX_VALUE)) {
                SubscriptionHelper.cancel(upstream);

                downstream.onError(ex);
            } else {
                RxJavaPlugins.onError(ex);
            }
        }

        @Override
        public void request(long n) {
            SubscriptionHelper.deferredRequest(upstream, requested, n);
        }

        @Override
        public void cancel() {
            SubscriptionHelper.cancel(upstream);
            task.dispose();
        }
    }

    static final class TimeoutFallbackSubscriber<T> extends SubscriptionArbiter
    implements FlowableSubscriber<T>, TimeoutSelectorSupport {

        private static final long serialVersionUID = 3764492702657003550L;

        final Subscriber<? super T> downstream;

        final Function<? super T, ? extends Publisher<?>> itemTimeoutIndicator;

        final SequentialDisposable task;

        final AtomicReference<Subscription> upstream;

        final AtomicLong index;

        Publisher<? extends T> fallback;

        long consumed;

        TimeoutFallbackSubscriber(Subscriber<? super T> actual,
                Function<? super T, ? extends Publisher<?>> itemTimeoutIndicator,
                        Publisher<? extends T> fallback) {
            super(true);
            this.downstream = actual;
            this.itemTimeoutIndicator = itemTimeoutIndicator;
            this.task = new SequentialDisposable();
            this.upstream = new AtomicReference<Subscription>();
            this.fallback = fallback;
            this.index = new AtomicLong();
        }

        @Override
        public void onSubscribe(Subscription s) {
            if (SubscriptionHelper.setOnce(this.upstream, s)) {
                setSubscription(s);
            }
        }

        @Override
        public void onNext(T t) {
            long idx = index.get();
            if (idx == Long.MAX_VALUE || !index.compareAndSet(idx, idx + 1)) {
                return;
            }

            Disposable d = task.get();
            if (d != null) {
                d.dispose();
            }

            consumed++;

            downstream.onNext(t);

            Publisher<?> itemTimeoutPublisher;

            try {
                itemTimeoutPublisher = ObjectHelper.requireNonNull(
                        itemTimeoutIndicator.apply(t),
                        "The itemTimeoutIndicator returned a null Publisher.");
            } catch (Throwable ex) {
                Exceptions.throwIfFatal(ex);
                upstream.get().cancel();
                index.getAndSet(Long.MAX_VALUE);
                downstream.onError(ex);
                return;
            }

            TimeoutConsumer consumer = new TimeoutConsumer(idx + 1, this);
            if (task.replace(consumer)) {
                itemTimeoutPublisher.subscribe(consumer);
            }
        }

        void startFirstTimeout(Publisher<?> firstTimeoutIndicator) {
            if (firstTimeoutIndicator != null) {
                TimeoutConsumer consumer = new TimeoutConsumer(0L, this);
                if (task.replace(consumer)) {
                    firstTimeoutIndicator.subscribe(consumer);
                }
            }
        }

        @Override
        public void onError(Throwable t) {
            if (index.getAndSet(Long.MAX_VALUE) != Long.MAX_VALUE) {
                task.dispose();

                downstream.onError(t);

                task.dispose();
            } else {
                RxJavaPlugins.onError(t);
            }
        }

        @Override
        public void onComplete() {
            if (index.getAndSet(Long.MAX_VALUE) != Long.MAX_VALUE) {
                task.dispose();

                downstream.onComplete();

                task.dispose();
            }
        }

        @Override
        public void onTimeout(long idx) {
            if (index.compareAndSet(idx, Long.MAX_VALUE)) {
                SubscriptionHelper.cancel(upstream);

                Publisher<? extends T> f = fallback;
                fallback = null;

                long c = consumed;
                if (c != 0L) {
                    produced(c);
                }

                f.subscribe(new FlowableTimeoutTimed.FallbackSubscriber<T>(downstream, this));
            }
        }

        @Override
        public void onTimeoutError(long idx, Throwable ex) {
            if (index.compareAndSet(idx, Long.MAX_VALUE)) {
                SubscriptionHelper.cancel(upstream);

                downstream.onError(ex);
            } else {
                RxJavaPlugins.onError(ex);
            }
        }

        @Override
        public void cancel() {
            super.cancel();
            task.dispose();
        }
    }

    static final class TimeoutConsumer extends AtomicReference<Subscription>
    implements FlowableSubscriber<Object>, Disposable {

        private static final long serialVersionUID = 8708641127342403073L;

        final TimeoutSelectorSupport parent;

        final long idx;

        TimeoutConsumer(long idx, TimeoutSelectorSupport parent) {
            this.idx = idx;
            this.parent = parent;
        }

        @Override
        public void onSubscribe(Subscription s) {
            SubscriptionHelper.setOnce(this, s, Long.MAX_VALUE);
        }

        @Override
        public void onNext(Object t) {
            Subscription upstream = get();
            if (upstream != SubscriptionHelper.CANCELLED) {
                upstream.cancel();
                lazySet(SubscriptionHelper.CANCELLED);
                parent.onTimeout(idx);
            }
        }

        @Override
        public void onError(Throwable t) {
            if (get() != SubscriptionHelper.CANCELLED) {
                lazySet(SubscriptionHelper.CANCELLED);
                parent.onTimeoutError(idx, t);
            } else {
                RxJavaPlugins.onError(t);
            }
        }

        @Override
        public void onComplete() {
            if (get() != SubscriptionHelper.CANCELLED) {
                lazySet(SubscriptionHelper.CANCELLED);
                parent.onTimeout(idx);
            }
        }

        @Override
        public void dispose() {
            SubscriptionHelper.cancel(this);
        }

        @Override
        public boolean isDisposed() {
            return this.get() == SubscriptionHelper.CANCELLED;
        }
    }

}