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Easy Redis Java client and Real-Time Data Platform. Valkey compatible. Sync/Async/RxJava3/Reactive API. Client side caching. Over 50 Redis based Java objects and services: JCache API, Apache Tomcat, Hibernate, Spring, Set, Multimap, SortedSet, Map, List, Queue, Deque, Semaphore, Lock, AtomicLong, Map Reduce, Bloom filter, Scheduler, RPC
/*
* Copyright (c) 2018-2021 VMware Inc. or its affiliates, 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.Queue;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.atomic.AtomicLongFieldUpdater;
import org.reactivestreams.Subscriber;
import reactor.core.CoreSubscriber;
import reactor.core.Disposable;
import reactor.core.Exceptions;
import reactor.util.annotation.Nullable;
/**
* Abstract base class for subscribers that hold another subscriber, a queue
* and requires queue-drain behavior.
*
* @param the source type to which this subscriber will be subscribed
* @param the value type in the queue
* @param the value type the child subscriber accepts
*
* @author Simon Baslé
* @author David Karnok
*/
abstract class QueueDrainSubscriber extends QueueDrainSubscriberPad4
implements InnerOperator {
final CoreSubscriber actual;
final Queue queue;
volatile boolean cancelled;
volatile boolean done;
Throwable error;
QueueDrainSubscriber(CoreSubscriber actual, Queue queue) {
this.actual = actual;
this.queue = queue;
}
@Override
public CoreSubscriber actual() {
return actual;
}
public final boolean cancelled() {
return cancelled;
}
public final boolean done() {
return done;
}
public final boolean enter() {
return wip.getAndIncrement() == 0;
}
public final boolean fastEnter() {
return wip.get() == 0 && wip.compareAndSet(0, 1);
}
protected final void fastPathEmitMax(U value, boolean delayError, Disposable dispose) {
final Subscriber s = actual;
final Queue q = queue;
if (wip.get() == 0 && wip.compareAndSet(0, 1)) {
long r = requested;
if (r != 0L) {
if (accept(s, value)) {
if (r != Long.MAX_VALUE) {
produced(1);
}
}
if (leave(-1) == 0) {
return;
}
} else {
dispose.dispose();
s.onError(Exceptions.failWithOverflow("Could not emit buffer due to lack of requests"));
return;
}
} else {
q.offer(value);
if (!enter()) {
return;
}
}
drainMaxLoop(q, s, delayError, dispose, this);
}
protected final void fastPathOrderedEmitMax(U value, boolean delayError, Disposable dispose) {
final Subscriber s = actual;
final Queue q = queue;
if (wip.get() == 0 && wip.compareAndSet(0, 1)) {
long r = requested;
if (r != 0L) {
if (q.isEmpty()) {
if (accept(s, value)) {
if (r != Long.MAX_VALUE) {
produced(1);
}
}
if (leave(-1) == 0) {
return;
}
} else {
q.offer(value);
}
} else {
cancelled = true;
dispose.dispose();
s.onError(Exceptions.failWithOverflow("Could not emit buffer due to lack of requests"));
return;
}
} else {
q.offer(value);
if (!enter()) {
return;
}
}
drainMaxLoop(q, s, delayError, dispose, this);
}
/**
* Accept the value and return true if forwarded.
* @param a the subscriber
* @param v the value
* @return true if the value was delivered
*/
public boolean accept(Subscriber a, U v) {
return false;
}
public final Throwable error() {
return error;
}
/**
* Adds m to the wip counter.
* @param m the value to add
* @return the current value after adding m
*/
public final int leave(int m) {
return wip.addAndGet(m);
}
public final long requested() {
return requested;
}
public final long produced(long n) {
return REQUESTED.addAndGet(this, -n);
}
public final void requested(long n) {
if (Operators.validate(n)) {
Operators.addCap(REQUESTED, this, n);
}
}
@Override
@Nullable
public Object scanUnsafe(Attr key) {
if (key == Attr.TERMINATED) return done;
if (key == Attr.CANCELLED) return cancelled;
if (key == Attr.REQUESTED_FROM_DOWNSTREAM) return requested;
if (key == Attr.ERROR) return error;
return InnerOperator.super.scanUnsafe(key);
}
/**
* Drain the queue but give up with an error if there aren't enough requests.
* @param the queue value type
* @param the emission value type
* @param q the queue
* @param a the subscriber
* @param delayError true if errors should be delayed after all normal items
* @param dispose the disposable to call when termination happens and cleanup is necessary
* @param qd the QueueDrain instance that gives status information to the drain logic
*/
static void drainMaxLoop(Queue q, Subscriber a, boolean delayError,
Disposable dispose, QueueDrainSubscriber qd) {
int missed = 1;
for (;;) {
for (;;) {
boolean d = qd.done();
Q v = q.poll();
boolean empty = v == null;
if (checkTerminated(d, empty, a, delayError, q, qd)) {
if (dispose != null) {
dispose.dispose();
}
return;
}
if (empty) {
break;
}
long r = qd.requested();
if (r != 0L) {
if (qd.accept(a, v)) {
if (r != Long.MAX_VALUE) {
qd.produced(1);
}
}
} else {
q.clear();
if (dispose != null) {
dispose.dispose();
}
a.onError(Exceptions.failWithOverflow("Could not emit value due to lack of requests."));
return;
}
}
missed = qd.leave(-missed);
if (missed == 0) {
break;
}
}
}
static boolean checkTerminated(boolean d, boolean empty,
Subscriber s, boolean delayError, Queue q, QueueDrainSubscriber qd) {
if (qd.cancelled()) {
q.clear();
return true;
}
if (d) {
if (delayError) {
if (empty) {
Throwable err = qd.error();
if (err != null) {
s.onError(err);
} else {
s.onComplete();
}
return true;
}
} else {
Throwable err = qd.error();
if (err != null) {
q.clear();
s.onError(err);
return true;
} else
if (empty) {
s.onComplete();
return true;
}
}
}
return false;
}
}
// -------------------------------------------------------------------
// Padding superclasses
//-------------------------------------------------------------------
/** Pads the header away from other fields. */
class QueueDrainSubscriberPad0 {
volatile long p1, p2, p3, p4, p5, p6, p7;
volatile long p8, p9, p10, p11, p12, p13, p14, p15;
}
/** The WIP counter. */
class QueueDrainSubscriberWip extends QueueDrainSubscriberPad0 {
final AtomicInteger wip = new AtomicInteger();
}
/** Pads away the wip from the other fields. */
class QueueDrainSubscriberPad2 extends QueueDrainSubscriberWip {
volatile long p1a, p2a, p3a, p4a, p5a, p6a, p7a;
volatile long p8a, p9a, p10a, p11a, p12a, p13a, p14a, p15a;
}
/** Contains the requested field. */
class QueueDrainSubscriberPad3 extends QueueDrainSubscriberPad2 {
static final AtomicLongFieldUpdater REQUESTED =
AtomicLongFieldUpdater.newUpdater(QueueDrainSubscriberPad3.class, "requested");
volatile long requested;
}
/** Pads away the requested from the other fields. */
class QueueDrainSubscriberPad4 extends QueueDrainSubscriberPad3 {
volatile long q1, q2, q3, q4, q5, q6, q7;
volatile long q8, q9, q10, q11, q12, q13, q14, q15;
}
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