/*
* 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
*
* 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 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 <T> the value type
*
* @see <a href="https://github.com/reactor/reactive-streams-commons">Reactive-Streams-Commons</a>
*/
final class
FluxPublishOn<T> extends
FluxOperator<T, T> implements
Fuseable {
final
Scheduler scheduler;
final boolean
delayError;
final
Supplier<? extends
Queue<T>>
queueSupplier;
final int
prefetch;
final int
lowTide;
FluxPublishOn(
Flux<? extends T>
source,
Scheduler scheduler,
boolean
delayError,
int
prefetch,
int
lowTide,
Supplier<? extends
Queue<T>>
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;
return super.scanUnsafe(
key);
}
@
Override
public int
getPrefetch() {
return
prefetch;
}
@
Override
@
SuppressWarnings("unchecked")
public void
subscribe(
CoreSubscriber<? super T>
actual) {
Worker worker;
try {
worker =
Objects.
requireNonNull(
scheduler.
createWorker(),
"The scheduler returned a null worker");
}
catch (
Throwable e) {
Operators.
error(
actual,
Operators.
onOperatorError(
e,
actual.
currentContext()));
return;
}
if (
actual instanceof
ConditionalSubscriber) {
ConditionalSubscriber<? super T>
cs = (
ConditionalSubscriber<? super T>)
actual;
source.
subscribe(new
PublishOnConditionalSubscriber<>(
cs,
scheduler,
worker,
delayError,
prefetch,
lowTide,
queueSupplier));
return;
}
source.
subscribe(new
PublishOnSubscriber<>(
actual,
scheduler,
worker,
delayError,
prefetch,
lowTide,
queueSupplier));
}
static final class
PublishOnSubscriber<T>
implements
QueueSubscription<T>,
Runnable,
InnerOperator<T, T> {
final
CoreSubscriber<? super T>
actual;
final
Scheduler scheduler;
final
Worker worker;
final boolean
delayError;
final int
prefetch;
final int
limit;
final
Supplier<? extends
Queue<T>>
queueSupplier;
Subscription s;
Queue<T>
queue;
volatile boolean
cancelled;
volatile boolean
done;
Throwable error;
volatile int
wip;
@
SuppressWarnings("rawtypes")
static final
AtomicIntegerFieldUpdater<
PublishOnSubscriber>
WIP =
AtomicIntegerFieldUpdater.
newUpdater(
PublishOnSubscriber.class, "wip");
volatile long
requested;
@
SuppressWarnings("rawtypes")
static final
AtomicLongFieldUpdater<
PublishOnSubscriber>
REQUESTED =
AtomicLongFieldUpdater.
newUpdater(
PublishOnSubscriber.class, "requested");
int
sourceMode;
long
produced;
boolean
outputFused;
PublishOnSubscriber(
CoreSubscriber<? super T>
actual,
Scheduler scheduler,
Worker worker,
boolean
delayError,
int
prefetch,
int
lowTide,
Supplier<? extends
Queue<T>>
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<T>
f =
(
QueueSubscription<T>)
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 (!
queue.
offer(
t)) {
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) {
Operators.
onDiscardQueueWithClear(
queue,
actual.
currentContext(), null);
}
}
void
trySchedule(
@
Nullable Subscription subscription,
@
Nullable Throwable suppressed,
@
Nullable Object dataSignal) {
if (
WIP.
getAndIncrement(this) != 0) {
return;
}
try {
worker.
schedule(this);
}
catch (
RejectedExecutionException ree) {
Operators.
onDiscardQueueWithClear(
queue,
actual.
currentContext(), null);
actual.
onError(
Operators.
onRejectedExecution(
ree,
subscription,
suppressed,
dataSignal,
actual.
currentContext()));
}
}
void
runSync() {
int
missed = 1;
final
Subscriber<? super T>
a =
actual;
final
Queue<T>
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.
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<? super T>
a =
actual;
final
Queue<T>
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();
Operators.
onDiscardQueueWithClear(
q,
actual.
currentContext(), null);
doError(
a,
Operators.
onOperatorError(
ex,
actual.
currentContext()));
return;
}
boolean
empty =
v == null;
if (
checkTerminated(
d,
empty,
a)) {
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)) {
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) {
Operators.
onDiscardQueueWithClear(
queue,
actual.
currentContext(), null);
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) {
if (
cancelled) {
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.
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;
return
InnerOperator.super.scanUnsafe(
key);
}
@
Override
public
CoreSubscriber<? super T>
actual() {
return
actual;
}
@
Override
public void
clear() {
Operators.
onDiscardQueueWithClear(
queue,
actual.
currentContext(), null);
}
@
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<T>
implements
QueueSubscription<T>,
Runnable,
InnerOperator<T, T> {
final
ConditionalSubscriber<? super T>
actual;
final
Worker worker;
final
Scheduler scheduler;
final boolean
delayError;
final int
prefetch;
final int
limit;
final
Supplier<? extends
Queue<T>>
queueSupplier;
Subscription s;
Queue<T>
queue;
volatile boolean
cancelled;
volatile boolean
done;
Throwable error;
volatile int
wip;
@
SuppressWarnings("rawtypes")
static final
AtomicIntegerFieldUpdater<
PublishOnConditionalSubscriber>
WIP =
AtomicIntegerFieldUpdater.
newUpdater(
PublishOnConditionalSubscriber.class,
"wip");
volatile long
requested;
@
SuppressWarnings("rawtypes")
static final
AtomicLongFieldUpdater<
PublishOnConditionalSubscriber>
REQUESTED =
AtomicLongFieldUpdater.
newUpdater(
PublishOnConditionalSubscriber.class,
"requested");
int
sourceMode;
long
produced;
long
consumed;
boolean
outputFused;
PublishOnConditionalSubscriber(
ConditionalSubscriber<? super T>
actual,
Scheduler scheduler,
Worker worker,
boolean
delayError,
int
prefetch,
int
lowTide,
Supplier<? extends
Queue<T>>
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<T>
f =
(
QueueSubscription<T>)
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);
return;
}
if (
done) {
Operators.
onNextDropped(
t,
actual.
currentContext());
return;
}
if (!
queue.
offer(
t)) {
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) {
Operators.
onDiscardQueueWithClear(
queue,
actual.
currentContext(), null);
}
}
void
trySchedule(
@
Nullable Subscription subscription,
@
Nullable Throwable suppressed,
@
Nullable Object dataSignal) {
if (
WIP.
getAndIncrement(this) != 0) {
return;
}
try {
worker.
schedule(this);
}
catch (
RejectedExecutionException ree) {
Operators.
onDiscardQueueWithClear(
queue,
actual.
currentContext(), null);
actual.
onError(
Operators.
onRejectedExecution(
ree,
subscription,
suppressed,
dataSignal,
actual.
currentContext()));
}
}
void
runSync() {
int
missed = 1;
final
ConditionalSubscriber<? super T>
a =
actual;
final
Queue<T>
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.
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<? super T>
a =
actual;
final
Queue<T>
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();
Operators.
onDiscardQueueWithClear(
q,
actual.
currentContext(), null);
doError(
a,
Operators.
onOperatorError(
ex,
actual.
currentContext()));
return;
}
boolean
empty =
v == null;
if (
checkTerminated(
d,
empty,
a)) {
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)) {
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) {
Operators.
onDiscardQueueWithClear(
queue,
actual.
currentContext(), null);
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<? super T>
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;
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) {
if (
cancelled) {
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.
onDiscardQueueWithClear(
queue,
actual.
currentContext(), null);
doError(
a,
e);
return true;
}
else if (
empty) {
doComplete(
a);
return true;
}
}
}
return false;
}
@
Override
public void
clear() {
Operators.
onDiscardQueueWithClear(
queue,
actual.
currentContext(), null);
}
@
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();
}
}
}