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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) 2016-2023 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.Objects;
import java.util.Queue;
import java.util.concurrent.RejectedExecutionException;
import java.util.concurrent.atomic.AtomicIntegerFieldUpdater;
import java.util.concurrent.atomic.AtomicLongFieldUpdater;
import java.util.function.Supplier;
import org.reactivestreams.Subscriber;
import org.reactivestreams.Subscription;
import reactor.core.CoreSubscriber;
import reactor.core.Exceptions;
import reactor.core.Fuseable;
import reactor.core.scheduler.Scheduler;
import reactor.core.scheduler.Scheduler.Worker;
import reactor.util.annotation.Nullable;
/**
* Emits events on a different thread specified by a scheduler callback.
*
* @param the value type
*
* @see Reactive-Streams-Commons
*/
final class FluxPublishOn extends InternalFluxOperator implements Fuseable {
final Scheduler scheduler;
final boolean delayError;
final Supplier> queueSupplier;
final int prefetch;
final int lowTide;
FluxPublishOn(Flux source,
Scheduler scheduler,
boolean delayError,
int prefetch,
int lowTide,
Supplier> queueSupplier) {
super(source);
if (prefetch <= 0) {
throw new IllegalArgumentException("prefetch > 0 required but it was " + prefetch);
}
this.scheduler = Objects.requireNonNull(scheduler, "scheduler");
this.delayError = delayError;
this.prefetch = prefetch;
this.lowTide = lowTide;
this.queueSupplier = Objects.requireNonNull(queueSupplier, "queueSupplier");
}
@Override
public Object scanUnsafe(Attr key) {
if (key == Attr.RUN_ON) return scheduler;
if (key == Attr.RUN_STYLE) return Attr.RunStyle.ASYNC;
return super.scanUnsafe(key);
}
@Override
public int getPrefetch() {
return prefetch;
}
@Override
@SuppressWarnings("unchecked")
public CoreSubscriber subscribeOrReturn(CoreSubscriber actual) {
Worker worker = Objects.requireNonNull(scheduler.createWorker(),
"The scheduler returned a null worker");
if (actual instanceof ConditionalSubscriber) {
ConditionalSubscriber cs = (ConditionalSubscriber) actual;
source.subscribe(new PublishOnConditionalSubscriber<>(cs,
scheduler,
worker,
delayError,
prefetch,
lowTide,
queueSupplier));
return null;
}
return new PublishOnSubscriber<>(actual,
scheduler,
worker,
delayError,
prefetch,
lowTide,
queueSupplier);
}
static final class PublishOnSubscriber
implements QueueSubscription, Runnable, InnerOperator {
final CoreSubscriber actual;
final Scheduler scheduler;
final Worker worker;
final boolean delayError;
final int prefetch;
final int limit;
final Supplier> queueSupplier;
Subscription s;
Queue queue;
volatile boolean cancelled;
volatile boolean done;
Throwable error;
volatile int wip;
@SuppressWarnings("rawtypes")
static final AtomicIntegerFieldUpdater WIP =
AtomicIntegerFieldUpdater.newUpdater(PublishOnSubscriber.class, "wip");
volatile int discardGuard;
@SuppressWarnings("rawtypes")
static final AtomicIntegerFieldUpdater DISCARD_GUARD =
AtomicIntegerFieldUpdater.newUpdater(PublishOnSubscriber.class, "discardGuard");
volatile long requested;
@SuppressWarnings("rawtypes")
static final AtomicLongFieldUpdater REQUESTED =
AtomicLongFieldUpdater.newUpdater(PublishOnSubscriber.class, "requested");
int sourceMode;
long produced;
boolean outputFused;
PublishOnSubscriber(CoreSubscriber actual,
Scheduler scheduler,
Worker worker,
boolean delayError,
int prefetch,
int lowTide,
Supplier> queueSupplier) {
this.actual = actual;
this.worker = worker;
this.scheduler = scheduler;
this.delayError = delayError;
this.prefetch = prefetch;
this.queueSupplier = queueSupplier;
this.limit = Operators.unboundedOrLimit(prefetch, lowTide);
}
@Override
public void onSubscribe(Subscription s) {
if (Operators.validate(this.s, s)) {
this.s = s;
if (s instanceof QueueSubscription) {
@SuppressWarnings("unchecked") QueueSubscription f =
(QueueSubscription) s;
int m = f.requestFusion(Fuseable.ANY | Fuseable.THREAD_BARRIER);
if (m == Fuseable.SYNC) {
sourceMode = Fuseable.SYNC;
queue = f;
done = true;
actual.onSubscribe(this);
return;
}
if (m == Fuseable.ASYNC) {
sourceMode = Fuseable.ASYNC;
queue = f;
actual.onSubscribe(this);
s.request(Operators.unboundedOrPrefetch(prefetch));
return;
}
}
queue = queueSupplier.get();
actual.onSubscribe(this);
s.request(Operators.unboundedOrPrefetch(prefetch));
}
}
@Override
public void onNext(T t) {
if (sourceMode == ASYNC) {
trySchedule(this, null, null /* t always null */);
return;
}
if (done) {
Operators.onNextDropped(t, actual.currentContext());
return;
}
if (cancelled) {
Operators.onDiscard(t, actual.currentContext());
return;
}
if (!queue.offer(t)) {
Operators.onDiscard(t, actual.currentContext());
error = Operators.onOperatorError(s,
Exceptions.failWithOverflow(Exceptions.BACKPRESSURE_ERROR_QUEUE_FULL),
t, actual.currentContext());
done = true;
}
trySchedule(this, null, t);
}
@Override
public void onError(Throwable t) {
if (done) {
Operators.onErrorDropped(t, actual.currentContext());
return;
}
error = t;
done = true;
trySchedule(null, t, null);
}
@Override
public void onComplete() {
if (done) {
return;
}
done = true;
//WIP also guards, no competing onNext
trySchedule(null, null, null);
}
@Override
public void request(long n) {
if (Operators.validate(n)) {
Operators.addCap(REQUESTED, this, n);
//WIP also guards during request and onError is possible
trySchedule(this, null, null);
}
}
@Override
public void cancel() {
if (cancelled) {
return;
}
cancelled = true;
s.cancel();
worker.dispose();
if (WIP.getAndIncrement(this) == 0) {
if (sourceMode == ASYNC) {
// delegates discarding to the queue holder to ensure there is no racing on draining from the SpScQueue
queue.clear();
}
else if (!outputFused) {
// discard MUST be happening only and only if there is no racing on elements consumption
// which is guaranteed by the WIP guard here in case non-fused output
Operators.onDiscardQueueWithClear(queue, actual.currentContext(), null);
}
}
}
void trySchedule(
@Nullable Subscription subscription,
@Nullable Throwable suppressed,
@Nullable Object dataSignal) {
if (WIP.getAndIncrement(this) != 0) {
if (cancelled) {
if (sourceMode == ASYNC) {
// delegates discarding to the queue holder to ensure there is no racing on draining from the SpScQueue
queue.clear();
}
else {
// discard given dataSignal since no more is enqueued (spec guarantees serialised onXXX calls)
Operators.onDiscard(dataSignal, actual.currentContext());
}
}
return;
}
try {
worker.schedule(this);
}
catch (RejectedExecutionException ree) {
if (sourceMode == ASYNC) {
// delegates discarding to the queue holder to ensure there is no racing on draining from the SpScQueue
queue.clear();
} else if (outputFused) {
// We are the holder of the queue, but we still have to perform discarding under the guarded block
// to prevent any racing done by downstream
this.clear();
}
else {
// In all other modes we are free to discard queue immediately since there is no racing on pooling
Operators.onDiscardQueueWithClear(queue, actual.currentContext(), null);
}
if (cancelled) {
Operators.onErrorDropped(ree, actual.currentContext());
return;
}
actual.onError(Operators.onRejectedExecution(ree, subscription, suppressed, dataSignal,
actual.currentContext()));
}
}
void runSync() {
int missed = 1;
final Subscriber a = actual;
final Queue q = queue;
long e = produced;
for (; ; ) {
long r = requested;
while (e != r) {
T v;
try {
v = q.poll();
}
catch (Throwable ex) {
doError(a, Operators.onOperatorError(s, ex,
actual.currentContext()));
return;
}
if (cancelled) {
Operators.onDiscard(v, actual.currentContext());
Operators.onDiscardQueueWithClear(q, actual.currentContext(), null);
return;
}
if (v == null) {
doComplete(a);
return;
}
a.onNext(v);
e++;
}
if (cancelled) {
Operators.onDiscardQueueWithClear(q, actual.currentContext(), null);
return;
}
if (q.isEmpty()) {
doComplete(a);
return;
}
int w = wip;
if (missed == w) {
produced = e;
missed = WIP.addAndGet(this, -missed);
if (missed == 0) {
break;
}
}
else {
missed = w;
}
}
}
void runAsync() {
int missed = 1;
final Subscriber a = actual;
final Queue q = queue;
long e = produced;
for (; ; ) {
long r = requested;
while (e != r) {
boolean d = done;
T v;
try {
v = q.poll();
}
catch (Throwable ex) {
Exceptions.throwIfFatal(ex);
s.cancel();
if (sourceMode == ASYNC) {
// delegates discarding to the queue holder to ensure there is no racing on draining from the SpScQueue
queue.clear();
} else {
// discard MUST be happening only and only if there is no racing on elements consumption
// which is guaranteed by the WIP guard here
Operators.onDiscardQueueWithClear(queue, actual.currentContext(), null);
}
doError(a, Operators.onOperatorError(ex, actual.currentContext()));
return;
}
boolean empty = v == null;
if (checkTerminated(d, empty, a, v)) {
return;
}
if (empty) {
break;
}
a.onNext(v);
e++;
if (e == limit) {
if (r != Long.MAX_VALUE) {
r = REQUESTED.addAndGet(this, -e);
}
s.request(e);
e = 0L;
}
}
if (e == r && checkTerminated(done, q.isEmpty(), a, null)) {
return;
}
int w = wip;
if (missed == w) {
produced = e;
missed = WIP.addAndGet(this, -missed);
if (missed == 0) {
break;
}
}
else {
missed = w;
}
}
}
void runBackfused() {
int missed = 1;
for (; ; ) {
if (cancelled) {
// We are the holder of the queue, but we still have to perform discarding under the guarded block
// to prevent any racing done by downstream
this.clear();
return;
}
boolean d = done;
actual.onNext(null);
if (d) {
Throwable e = error;
if (e != null) {
doError(actual, e);
}
else {
doComplete(actual);
}
return;
}
missed = WIP.addAndGet(this, -missed);
if (missed == 0) {
break;
}
}
}
void doComplete(Subscriber a) {
a.onComplete();
worker.dispose();
}
void doError(Subscriber a, Throwable e) {
try {
a.onError(e);
}
finally {
worker.dispose();
}
}
@Override
public void run() {
if (outputFused) {
runBackfused();
}
else if (sourceMode == Fuseable.SYNC) {
runSync();
}
else {
runAsync();
}
}
boolean checkTerminated(boolean d, boolean empty, Subscriber a, @Nullable T v) {
if (cancelled) {
Operators.onDiscard(v, actual.currentContext());
if (sourceMode == ASYNC) {
// delegates discarding to the queue holder to ensure there is no racing on draining from the SpScQueue
queue.clear();
} else {
// discard MUST be happening only and only if there is no racing on elements consumption
// which is guaranteed by the WIP guard here
Operators.onDiscardQueueWithClear(queue, actual.currentContext(), null);
}
return true;
}
if (d) {
if (delayError) {
if (empty) {
Throwable e = error;
if (e != null) {
doError(a, e);
}
else {
doComplete(a);
}
return true;
}
}
else {
Throwable e = error;
if (e != null) {
Operators.onDiscard(v, actual.currentContext());
if (sourceMode == ASYNC) {
// delegates discarding to the queue holder to ensure there is no racing on draining from the SpScQueue
queue.clear();
} else {
// discard MUST be happening only and only if there is no racing on elements consumption
// which is guaranteed by the WIP guard here
Operators.onDiscardQueueWithClear(queue, actual.currentContext(), null);
}
doError(a, e);
return true;
}
else if (empty) {
doComplete(a);
return true;
}
}
}
return false;
}
@Override
@Nullable
public Object scanUnsafe(Attr key) {
if (key == Attr.REQUESTED_FROM_DOWNSTREAM ) return requested;
if (key == Attr.PARENT ) return s;
if (key == Attr.CANCELLED) return cancelled;
if (key == Attr.TERMINATED) return done;
if (key == Attr.BUFFERED) return queue != null ? queue.size() : 0;
if (key == Attr.ERROR) return error;
if (key == Attr.DELAY_ERROR) return delayError;
if (key == Attr.PREFETCH) return prefetch;
if (key == Attr.RUN_ON) return worker;
if (key == Attr.RUN_STYLE) return Attr.RunStyle.ASYNC;
return InnerOperator.super.scanUnsafe(key);
}
@Override
public CoreSubscriber actual() {
return actual;
}
@Override
public void clear() {
// use guard on the queue instance as the best way to ensure there is no racing on draining
// the call to this method must be done only during the ASYNC fusion so all the callers will be waiting
// this should not be performance costly with the assumption the cancel is rare operation
if (DISCARD_GUARD.getAndIncrement(this) != 0) {
return;
}
int missed = 1;
for (;;) {
Operators.onDiscardQueueWithClear(queue, actual.currentContext(), null);
int dg = discardGuard;
if (missed == dg) {
missed = DISCARD_GUARD.addAndGet(this, -missed);
if (missed == 0) {
break;
}
}
else {
missed = dg;
}
}
}
@Override
public boolean isEmpty() {
return queue.isEmpty();
}
@Override
@Nullable
public T poll() {
T v = queue.poll();
if (v != null && sourceMode != SYNC) {
long p = produced + 1;
if (p == limit) {
produced = 0;
s.request(p);
}
else {
produced = p;
}
}
return v;
}
@Override
public int requestFusion(int requestedMode) {
if ((requestedMode & ASYNC) != 0) {
outputFused = true;
return ASYNC;
}
return NONE;
}
@Override
public int size() {
return queue.size();
}
}
static final class PublishOnConditionalSubscriber
implements QueueSubscription, Runnable, InnerOperator {
final ConditionalSubscriber actual;
final Worker worker;
final Scheduler scheduler;
final boolean delayError;
final int prefetch;
final int limit;
final Supplier> queueSupplier;
Subscription s;
Queue queue;
volatile boolean cancelled;
volatile boolean done;
Throwable error;
volatile int wip;
@SuppressWarnings("rawtypes")
static final AtomicIntegerFieldUpdater WIP =
AtomicIntegerFieldUpdater.newUpdater(PublishOnConditionalSubscriber.class,
"wip");
volatile int discardGuard;
@SuppressWarnings("rawtypes")
static final AtomicIntegerFieldUpdater DISCARD_GUARD =
AtomicIntegerFieldUpdater.newUpdater(PublishOnConditionalSubscriber.class,
"discardGuard");
volatile long requested;
@SuppressWarnings("rawtypes")
static final AtomicLongFieldUpdater REQUESTED =
AtomicLongFieldUpdater.newUpdater(PublishOnConditionalSubscriber.class,
"requested");
int sourceMode;
long produced;
long consumed;
boolean outputFused;
PublishOnConditionalSubscriber(ConditionalSubscriber actual,
Scheduler scheduler,
Worker worker,
boolean delayError,
int prefetch,
int lowTide,
Supplier> queueSupplier) {
this.actual = actual;
this.worker = worker;
this.scheduler = scheduler;
this.delayError = delayError;
this.prefetch = prefetch;
this.queueSupplier = queueSupplier;
this.limit = Operators.unboundedOrLimit(prefetch, lowTide);
}
@Override
public void onSubscribe(Subscription s) {
if (Operators.validate(this.s, s)) {
this.s = s;
if (s instanceof QueueSubscription) {
@SuppressWarnings("unchecked") QueueSubscription f =
(QueueSubscription) s;
int m = f.requestFusion(Fuseable.ANY | Fuseable.THREAD_BARRIER);
if (m == Fuseable.SYNC) {
sourceMode = Fuseable.SYNC;
queue = f;
done = true;
actual.onSubscribe(this);
return;
}
if (m == Fuseable.ASYNC) {
sourceMode = Fuseable.ASYNC;
queue = f;
actual.onSubscribe(this);
s.request(Operators.unboundedOrPrefetch(prefetch));
return;
}
}
queue = queueSupplier.get();
actual.onSubscribe(this);
s.request(Operators.unboundedOrPrefetch(prefetch));
}
}
@Override
public void onNext(T t) {
if (sourceMode == ASYNC) {
trySchedule(this, null, null /* t always null */);
return;
}
if (done) {
Operators.onNextDropped(t, actual.currentContext());
return;
}
if (cancelled) {
Operators.onDiscard(t, actual.currentContext());
return;
}
if (!queue.offer(t)) {
Operators.onDiscard(t, actual.currentContext());
error = Operators.onOperatorError(s, Exceptions.failWithOverflow(Exceptions.BACKPRESSURE_ERROR_QUEUE_FULL), t,
actual.currentContext());
done = true;
}
trySchedule(this, null, t);
}
@Override
public void onError(Throwable t) {
if (done) {
Operators.onErrorDropped(t, actual.currentContext());
return;
}
error = t;
done = true;
trySchedule(null, t, null);
}
@Override
public void onComplete() {
if (done) {
return;
}
done = true;
trySchedule(null, null, null);
}
@Override
public void request(long n) {
if (Operators.validate(n)) {
Operators.addCap(REQUESTED, this, n);
trySchedule(this, null, null);
}
}
@Override
public void cancel() {
if (cancelled) {
return;
}
cancelled = true;
s.cancel();
worker.dispose();
if (WIP.getAndIncrement(this) == 0) {
if (sourceMode == ASYNC) {
// delegates discarding to the queue holder to ensure there is no racing on draining from the SpScQueue
queue.clear();
}
else if (!outputFused) {
// discard MUST be happening only and only if there is no racing on elements consumption
// which is guaranteed by the WIP guard here in case non-fused output
Operators.onDiscardQueueWithClear(queue, actual.currentContext(), null);
}
}
}
void trySchedule(
@Nullable Subscription subscription,
@Nullable Throwable suppressed,
@Nullable Object dataSignal) {
if (WIP.getAndIncrement(this) != 0) {
if (cancelled) {
if (sourceMode == ASYNC) {
// delegates discarding to the queue holder to ensure there is no racing on draining from the SpScQueue
queue.clear();
}
else {
// discard given dataSignal since no more is enqueued (spec guarantees serialised onXXX calls)
Operators.onDiscard(dataSignal, actual.currentContext());
}
}
return;
}
try {
worker.schedule(this);
}
catch (RejectedExecutionException ree) {
if (sourceMode == ASYNC) {
// delegates discarding to the queue holder to ensure there is no racing on draining from the SpScQueue
queue.clear();
} else if (outputFused) {
// We are the holder of the queue, but we still have to perform discarding under the guarded block
// to prevent any racing done by downstream
this.clear();
}
else {
// In all other modes we are free to discard queue immediately since there is no racing on pooling
Operators.onDiscardQueueWithClear(queue, actual.currentContext(), null);
}
if (cancelled) {
Operators.onErrorDropped(ree, actual.currentContext());
return;
}
actual.onError(Operators.onRejectedExecution(ree, subscription, suppressed, dataSignal,
actual.currentContext()));
}
}
void runSync() {
int missed = 1;
final ConditionalSubscriber a = actual;
final Queue q = queue;
long e = produced;
for (; ; ) {
long r = requested;
while (e != r) {
T v;
try {
v = q.poll();
}
catch (Throwable ex) {
doError(a, Operators.onOperatorError(s, ex,
actual.currentContext()));
return;
}
if (cancelled) {
Operators.onDiscard(v, actual.currentContext());
Operators.onDiscardQueueWithClear(q, actual.currentContext(), null);
return;
}
if (v == null) {
doComplete(a);
return;
}
if (a.tryOnNext(v)) {
e++;
}
}
if (cancelled) {
Operators.onDiscardQueueWithClear(q, actual.currentContext(), null);
return;
}
if (q.isEmpty()) {
doComplete(a);
return;
}
int w = wip;
if (missed == w) {
produced = e;
missed = WIP.addAndGet(this, -missed);
if (missed == 0) {
break;
}
}
else {
missed = w;
}
}
}
void runAsync() {
int missed = 1;
final ConditionalSubscriber a = actual;
final Queue q = queue;
long emitted = produced;
long polled = consumed;
for (; ; ) {
long r = requested;
while (emitted != r) {
boolean d = done;
T v;
try {
v = q.poll();
}
catch (Throwable ex) {
Exceptions.throwIfFatal(ex);
s.cancel();
// delegates discarding to the queue holder to ensure there is no racing on draining from the SpScQueue
q.clear();
doError(a, Operators.onOperatorError(ex, actual.currentContext()));
return;
}
boolean empty = v == null;
if (checkTerminated(d, empty, a, v)) {
return;
}
if (empty) {
break;
}
if (a.tryOnNext(v)) {
emitted++;
}
polled++;
if (polled == limit) {
s.request(polled);
polled = 0L;
}
}
if (emitted == r && checkTerminated(done, q.isEmpty(), a, null)) {
return;
}
int w = wip;
if (missed == w) {
produced = emitted;
consumed = polled;
missed = WIP.addAndGet(this, -missed);
if (missed == 0) {
break;
}
}
else {
missed = w;
}
}
}
void runBackfused() {
int missed = 1;
for (; ; ) {
if (cancelled) {
// We are the holder of the queue, but we still have to perform discarding under the guarded block
// to prevent any racing done by downstream
this.clear();
return;
}
boolean d = done;
actual.onNext(null);
if (d) {
Throwable e = error;
if (e != null) {
doError(actual, e);
}
else {
doComplete(actual);
}
return;
}
missed = WIP.addAndGet(this, -missed);
if (missed == 0) {
break;
}
}
}
@Override
public void run() {
if (outputFused) {
runBackfused();
}
else if (sourceMode == Fuseable.SYNC) {
runSync();
}
else {
runAsync();
}
}
@Override
public CoreSubscriber actual() {
return actual;
}
@Override
@Nullable
public Object scanUnsafe(Attr key) {
if (key == Attr.REQUESTED_FROM_DOWNSTREAM) return requested;
if (key == Attr.PARENT) return s;
if (key == Attr.CANCELLED) return cancelled;
if (key == Attr.TERMINATED) return done;
if (key == Attr.BUFFERED) return queue != null ? queue.size() : 0;
if (key == Attr.ERROR) return error;
if (key == Attr.DELAY_ERROR) return delayError;
if (key == Attr.PREFETCH) return prefetch;
if (key == Attr.RUN_ON) return worker;
if (key == Attr.RUN_STYLE) return Attr.RunStyle.ASYNC;
return InnerOperator.super.scanUnsafe(key);
}
void doComplete(Subscriber a) {
a.onComplete();
worker.dispose();
}
void doError(Subscriber a, Throwable e) {
try {
a.onError(e);
}
finally {
worker.dispose();
}
}
boolean checkTerminated(boolean d, boolean empty, Subscriber a, @Nullable T v) {
if (cancelled) {
Operators.onDiscard(v, actual.currentContext());
if (sourceMode == ASYNC) {
// delegates discarding to the queue holder to ensure there is no racing on draining from the SpScQueue
queue.clear();
} else {
// discard MUST be happening only and only if there is no racing on elements consumption
// which is guaranteed by the WIP guard here
Operators.onDiscardQueueWithClear(queue, actual.currentContext(), null);
}
return true;
}
if (d) {
if (delayError) {
if (empty) {
Throwable e = error;
if (e != null) {
doError(a, e);
}
else {
doComplete(a);
}
return true;
}
}
else {
Throwable e = error;
if (e != null) {
Operators.onDiscard(v, actual.currentContext());
if (sourceMode == ASYNC) {
// delegates discarding to the queue holder to ensure there is no racing on draining from the SpScQueue
queue.clear();
} else {
// discard MUST be happening only and only if there is no racing on elements consumption
// which is guaranteed by the WIP guard here
Operators.onDiscardQueueWithClear(queue, actual.currentContext(), null);
}
doError(a, e);
return true;
}
else if (empty) {
doComplete(a);
return true;
}
}
}
return false;
}
@Override
public void clear() {
// use guard on the queue instance as the best way to ensure there is no racing on draining
// the call to this method must be done only during the ASYNC fusion so all the callers will be waiting
// this should not be performance costly with the assumption the cancel is rare operation
if (DISCARD_GUARD.getAndIncrement(this) != 0) {
return;
}
int missed = 1;
for (;;) {
Operators.onDiscardQueueWithClear(queue, actual.currentContext(), null);
int dg = discardGuard;
if (missed == dg) {
missed = DISCARD_GUARD.addAndGet(this, -missed);
if (missed == 0) {
break;
}
}
else {
missed = dg;
}
}
}
@Override
public boolean isEmpty() {
return queue.isEmpty();
}
@Override
@Nullable
public T poll() {
T v = queue.poll();
if (v != null && sourceMode != SYNC) {
long p = consumed + 1;
if (p == limit) {
consumed = 0;
s.request(p);
}
else {
consumed = p;
}
}
return v;
}
@Override
public int requestFusion(int requestedMode) {
if ((requestedMode & ASYNC) != 0) {
outputFused = true;
return ASYNC;
}
return NONE;
}
@Override
public int size() {
return queue.size();
}
}
}
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