/*
 * Copyright (c) 2011-2017 Pivotal Software Inc, All Rights Reserved.
 *
 * 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
 *
 *       https://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 reactor.core.publisher;

import java.util.Objects;
import java.util.concurrent.TimeoutException;
import java.util.concurrent.atomic.AtomicLongFieldUpdater;
import java.util.concurrent.atomic.AtomicReferenceFieldUpdater;
import java.util.function.Function;

import org.reactivestreams.Publisher;
import org.reactivestreams.Subscriber;
import org.reactivestreams.Subscription;
import reactor.core.CoreSubscriber;
import reactor.core.Scannable;
import reactor.util.annotation.Nullable;
import reactor.util.context.Context;

Signals a timeout (or switches to another sequence) in case a per-item generated Publisher source fires an item or completes before the next item arrives from the main source.
Type parameters:
  • <T> – the main source type
  • <U> – the value type for the timeout for the very first item
  • <V> – the value type for the timeout for the subsequent items
See Also:
/** * Signals a timeout (or switches to another sequence) in case a per-item * generated Publisher source fires an item or completes before the next item * arrives from the main source. * * @param <T> the main source type * @param <U> the value type for the timeout for the very first item * @param <V> the value type for the timeout for the subsequent items * * @see <a href="https://github.com/reactor/reactive-streams-commons">Reactive-Streams-Commons</a> */
final class FluxTimeout<T, U, V> extends InternalFluxOperator<T, T> { final Publisher<U> firstTimeout; final Function<? super T, ? extends Publisher<V>> itemTimeout; final Publisher<? extends T> other; final String timeoutDescription; //only useful when no `other` FluxTimeout(Flux<? extends T> source, Publisher<U> firstTimeout, Function<? super T, ? extends Publisher<V>> itemTimeout, String timeoutDescription) { super(source); this.firstTimeout = Objects.requireNonNull(firstTimeout, "firstTimeout"); this.itemTimeout = Objects.requireNonNull(itemTimeout, "itemTimeout"); this.other = null; this.timeoutDescription = addNameToTimeoutDescription(source, Objects.requireNonNull(timeoutDescription, "timeoutDescription is needed when no fallback")); } FluxTimeout(Flux<? extends T> source, Publisher<U> firstTimeout, Function<? super T, ? extends Publisher<V>> itemTimeout, Publisher<? extends T> other) { super(source); this.firstTimeout = Objects.requireNonNull(firstTimeout, "firstTimeout"); this.itemTimeout = Objects.requireNonNull(itemTimeout, "itemTimeout"); this.other = Objects.requireNonNull(other, "other"); this.timeoutDescription = null; } @Override public CoreSubscriber<? super T> subscribeOrReturn(CoreSubscriber<? super T> actual) { return new TimeoutMainSubscriber<>(actual, firstTimeout, itemTimeout, other, timeoutDescription); } @Nullable static String addNameToTimeoutDescription(Publisher<?> source, @Nullable String timeoutDescription) { if (timeoutDescription == null) { return null; } Scannable s = Scannable.from(source); if (s.isScanAvailable()) { return timeoutDescription + " in '" + s.name() + "'"; } else { return timeoutDescription; } } @Override public Object scanUnsafe(Attr key) { if (key == Attr.RUN_STYLE) return Attr.RunStyle.SYNC; return super.scanUnsafe(key); } static final class TimeoutMainSubscriber<T, V> extends Operators.MultiSubscriptionSubscriber<T, T> { final Publisher<?> firstTimeout; final Function<? super T, ? extends Publisher<V>> itemTimeout; final Publisher<? extends T> other; final String timeoutDescription; //only useful/non-null when no `other` Subscription s; volatile IndexedCancellable timeout; @SuppressWarnings("rawtypes") static final AtomicReferenceFieldUpdater<TimeoutMainSubscriber, IndexedCancellable> TIMEOUT = AtomicReferenceFieldUpdater.newUpdater(TimeoutMainSubscriber.class, IndexedCancellable.class, "timeout"); volatile long index; @SuppressWarnings("rawtypes") static final AtomicLongFieldUpdater<TimeoutMainSubscriber> INDEX = AtomicLongFieldUpdater.newUpdater(TimeoutMainSubscriber.class, "index"); TimeoutMainSubscriber( CoreSubscriber<? super T> actual, Publisher<?> firstTimeout, Function<? super T, ? extends Publisher<V>> itemTimeout, @Nullable Publisher<? extends T> other, @Nullable String timeoutDescription ) { super(Operators.serialize(actual)); this.itemTimeout = itemTimeout; this.other = other; this.timeoutDescription = timeoutDescription; this.firstTimeout = firstTimeout; } @Override public void onSubscribe(Subscription s) { if (Operators.validate(this.s, s)) { this.s = s; set(s); TimeoutTimeoutSubscriber timeoutSubscriber = new TimeoutTimeoutSubscriber(this, 0L); this.timeout = timeoutSubscriber; actual.onSubscribe(this); firstTimeout.subscribe(timeoutSubscriber); } } @Override protected boolean shouldCancelCurrent() { return true; } @Override public void onNext(T t) { timeout.cancel(); long idx = index; if (idx == Long.MIN_VALUE) { s.cancel(); Operators.onNextDropped(t, actual.currentContext()); return; } if (!INDEX.compareAndSet(this, idx, idx + 1)) { s.cancel(); Operators.onNextDropped(t, actual.currentContext()); return; } actual.onNext(t); producedOne(); Publisher<? extends V> p; try { p = Objects.requireNonNull(itemTimeout.apply(t), "The itemTimeout returned a null Publisher"); } catch (Throwable e) { actual.onError(Operators.onOperatorError(this, e, t, actual.currentContext())); return; } TimeoutTimeoutSubscriber ts = new TimeoutTimeoutSubscriber(this, idx + 1); if (!setTimeout(ts)) { return; } p.subscribe(ts); } @Override public void onError(Throwable t) { long idx = index; if (idx == Long.MIN_VALUE) { Operators.onErrorDropped(t, actual.currentContext()); return; } if (!INDEX.compareAndSet(this, idx, Long.MIN_VALUE)) { Operators.onErrorDropped(t, actual.currentContext()); return; } cancelTimeout(); actual.onError(t); } @Override public void onComplete() { long idx = index; if (idx == Long.MIN_VALUE) { return; } if (!INDEX.compareAndSet(this, idx, Long.MIN_VALUE)) { return; } cancelTimeout(); actual.onComplete(); } void cancelTimeout() { IndexedCancellable s = timeout; if (s != CancelledIndexedCancellable.INSTANCE) { s = TIMEOUT.getAndSet(this, CancelledIndexedCancellable.INSTANCE); if (s != null && s != CancelledIndexedCancellable.INSTANCE) { s.cancel(); } } } @Override public void cancel() { index = Long.MIN_VALUE; cancelTimeout(); super.cancel(); } boolean setTimeout(IndexedCancellable newTimeout) { for (; ; ) { IndexedCancellable currentTimeout = timeout; if (currentTimeout == CancelledIndexedCancellable.INSTANCE) { newTimeout.cancel(); return false; } if (currentTimeout != null && currentTimeout.index() >= newTimeout.index()) { newTimeout.cancel(); return false; } if (TIMEOUT.compareAndSet(this, currentTimeout, newTimeout)) { if (currentTimeout != null) { currentTimeout.cancel(); } return true; } } } void doTimeout(long i) { if (index == i && INDEX.compareAndSet(this, i, Long.MIN_VALUE)) { handleTimeout(); } } void doError(long i, Throwable e) { if (index == i && INDEX.compareAndSet(this, i, Long.MIN_VALUE)) { super.cancel(); actual.onError(e); } } void handleTimeout() { if (other == null) { super.cancel(); actual.onError(new TimeoutException("Did not observe any item or terminal signal within " + timeoutDescription + " (and no fallback has been configured)")); } else { set(Operators.emptySubscription()); other.subscribe(new TimeoutOtherSubscriber<>(actual, this)); } } @Override public Object scanUnsafe(Attr key) { if (key == Attr.RUN_STYLE) return Attr.RunStyle.SYNC; return super.scanUnsafe(key); } } static final class TimeoutOtherSubscriber<T> implements InnerConsumer<T> { final CoreSubscriber<? super T> actual; final Operators.MultiSubscriptionSubscriber<T, T> arbiter; TimeoutOtherSubscriber(CoreSubscriber<? super T> actual, Operators.MultiSubscriptionSubscriber<T, T> arbiter) { this.actual = actual; this.arbiter = arbiter; } @Override public Context currentContext() { return actual.currentContext(); } @Override public void onSubscribe(Subscription s) { arbiter.set(s); } @Override public void onNext(T t) { actual.onNext(t); } @Override public void onError(Throwable t) { actual.onError(t); } @Override public void onComplete() { actual.onComplete(); } @Override public Object scanUnsafe(Attr key) { if (key == Attr.RUN_STYLE) return Attr.RunStyle.SYNC; return null; } } interface IndexedCancellable { long index(); void cancel(); } enum CancelledIndexedCancellable implements IndexedCancellable { INSTANCE; @Override public long index() { return Long.MAX_VALUE; } @Override public void cancel() { } } static final class TimeoutTimeoutSubscriber implements InnerConsumer<Object>, IndexedCancellable { final TimeoutMainSubscriber<?, ?> main; final long index; volatile Subscription s; static final AtomicReferenceFieldUpdater<TimeoutTimeoutSubscriber, Subscription> S = AtomicReferenceFieldUpdater.newUpdater(TimeoutTimeoutSubscriber.class, Subscription.class, "s"); TimeoutTimeoutSubscriber(TimeoutMainSubscriber<?, ?> main, long index) { this.main = main; this.index = index; } @Override public Context currentContext() { return main.currentContext(); } @Override public void onSubscribe(Subscription s) { if (!S.compareAndSet(this, null, s)) { s.cancel(); if (this.s != Operators.cancelledSubscription()) { Operators.reportSubscriptionSet(); } } else { s.request(Long.MAX_VALUE); } } @Override public void onNext(Object t) { s.cancel(); main.doTimeout(index); } @Override public void onError(Throwable t) { main.doError(index, t); } @Override public void onComplete() { main.doTimeout(index); } @Override public void cancel() { Subscription a = s; if (a != Operators.cancelledSubscription()) { a = S.getAndSet(this, Operators.cancelledSubscription()); if (a != null && a != Operators.cancelledSubscription()) { a.cancel(); } } } @Override public long index() { return index; } @Override public Object scanUnsafe(Attr key) { if (key == Attr.RUN_STYLE) return Attr.RunStyle.SYNC; return null; } } }