/*
* 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.atomic.
AtomicIntegerFieldUpdater;
import java.util.concurrent.atomic.
AtomicLongFieldUpdater;
import java.util.concurrent.atomic.
AtomicReferenceFieldUpdater;
import java.util.function.
Function;
import java.util.function.
Supplier;
import java.util.stream.
Stream;
import org.reactivestreams.
Publisher;
import org.reactivestreams.
Subscription;
import reactor.core.
CoreSubscriber;
import reactor.core.
Exceptions;
import reactor.core.
Fuseable;
import reactor.core.
Scannable;
import reactor.util.annotation.
Nullable;
import reactor.util.context.
Context;
/**
* Shares a sequence for the duration of a function that may transform it and consume it
* as many times as necessary without causing multiple subscriptions to the upstream.
*
* @param <T> the source value type
* @param <R> the output value type
*
* @see <a href="https://github.com/reactor/reactive-streams-commons">Reactive-Streams-Commons</a>
*/
final class
FluxPublishMulticast<T, R> extends
FluxOperator<T, R> implements
Fuseable {
final
Function<? super
Flux<T>, ? extends
Publisher<? extends R>>
transform;
final
Supplier<? extends
Queue<T>>
queueSupplier;
final int
prefetch;
FluxPublishMulticast(
Flux<? extends T>
source,
Function<? super
Flux<T>, ? extends
Publisher<? extends R>>
transform,
int
prefetch,
Supplier<? extends
Queue<T>>
queueSupplier) {
super(
source);
if (
prefetch < 1) {
throw new
IllegalArgumentException("prefetch > 0 required but it was " +
prefetch);
}
this.
prefetch =
prefetch;
this.
transform =
Objects.
requireNonNull(
transform, "transform");
this.
queueSupplier =
Objects.
requireNonNull(
queueSupplier, "queueSupplier");
}
@
Override
public int
getPrefetch() {
return
prefetch;
}
@
Override
public void
subscribe(
CoreSubscriber<? super R>
actual) {
FluxPublishMulticaster<T>
multicast = new
FluxPublishMulticaster<>(
prefetch,
queueSupplier,
actual.
currentContext());
Publisher<? extends R>
out;
try {
out =
Objects.
requireNonNull(
transform.
apply(
multicast),
"The transform returned a null Publisher");
}
catch (
Throwable ex) {
Operators.
error(
actual,
Operators.
onOperatorError(
ex,
actual.
currentContext()));
return;
}
if (
out instanceof
Fuseable) {
out.
subscribe(new
CancelFuseableMulticaster<>(
actual,
multicast));
}
else {
out.
subscribe(new
CancelMulticaster<>(
actual,
multicast));
}
source.
subscribe(
multicast);
}
static final class
FluxPublishMulticaster<T> extends
Flux<T>
implements
InnerConsumer<T>,
PublishMulticasterParent {
final int
limit;
final int
prefetch;
final
Supplier<? extends
Queue<T>>
queueSupplier;
Queue<T>
queue;
volatile
Subscription s;
@
SuppressWarnings("rawtypes")
static final
AtomicReferenceFieldUpdater<
FluxPublishMulticaster,
Subscription>
S =
AtomicReferenceFieldUpdater.
newUpdater(
FluxPublishMulticaster.class,
Subscription.class,
"s");
volatile int
wip;
@
SuppressWarnings("rawtypes")
static final
AtomicIntegerFieldUpdater<
FluxPublishMulticaster>
WIP =
AtomicIntegerFieldUpdater.
newUpdater(
FluxPublishMulticaster.class, "wip");
volatile
PublishMulticastInner<T>[]
subscribers;
@
SuppressWarnings("rawtypes")
static final
AtomicReferenceFieldUpdater<
FluxPublishMulticaster,
PublishMulticastInner[]>
SUBSCRIBERS =
AtomicReferenceFieldUpdater.
newUpdater(
FluxPublishMulticaster.class,
PublishMulticastInner[].class,
"subscribers");
@
SuppressWarnings("rawtypes")
static final
PublishMulticastInner[]
EMPTY = new
PublishMulticastInner[0];
@
SuppressWarnings("rawtypes")
static final
PublishMulticastInner[]
TERMINATED = new
PublishMulticastInner[0];
volatile boolean
done;
volatile boolean
connected;
Throwable error;
final
Context context;
int
produced;
int
sourceMode;
@
SuppressWarnings("unchecked")
FluxPublishMulticaster(int
prefetch,
Supplier<? extends
Queue<T>>
queueSupplier,
Context ctx) {
this.
prefetch =
prefetch;
this.
limit =
Operators.
unboundedOrLimit(
prefetch);
this.
queueSupplier =
queueSupplier;
SUBSCRIBERS.
lazySet(this,
EMPTY);
this.
context =
ctx;
}
@
Override
@
Nullable
public
Object scanUnsafe(
Attr key) {
if (
key ==
Attr.
PARENT) {
return
s;
}
if (
key ==
Attr.
ERROR) {
return
error;
}
if (
key ==
Attr.
CANCELLED) {
return
s ==
Operators.
cancelledSubscription();
}
if (
key ==
Attr.
TERMINATED) {
return
done;
}
if (
key ==
Attr.
PREFETCH) {
return
prefetch;
}
if (
key ==
Attr.
BUFFERED) {
return
queue != null ?
queue.
size() : 0;
}
return null;
}
@
Override
public
Stream<? extends
Scannable>
inners() {
return
Stream.
of(
subscribers);
}
@
Override
public
Context currentContext() {
return
context;
}
@
Override
public void
subscribe(
CoreSubscriber<? super T>
actual) {
PublishMulticastInner<T>
pcs = new
PublishMulticastInner<>(this,
actual);
actual.
onSubscribe(
pcs);
if (
add(
pcs)) {
if (
pcs.
requested ==
Long.
MIN_VALUE) {
remove(
pcs);
return;
}
drain();
}
else {
Throwable ex =
error;
if (
ex != null) {
actual.
onError(
ex);
}
else {
actual.
onComplete();
}
}
}
@
Override
public void
onSubscribe(
Subscription s) {
if (
Operators.
setOnce(
S, this,
s)) {
if (
s instanceof
QueueSubscription) {
@
SuppressWarnings("unchecked")
QueueSubscription<T>
qs =
(
QueueSubscription<T>)
s;
int
m =
qs.
requestFusion(
Fuseable.
ANY);
if (
m ==
Fuseable.
SYNC) {
sourceMode =
m;
queue =
qs;
done = true;
connected = true;
drain();
return;
}
if (
m ==
Fuseable.
ASYNC) {
sourceMode =
m;
queue =
qs;
connected = true;
s.
request(
Operators.
unboundedOrPrefetch(
prefetch));
return;
}
}
queue =
queueSupplier.
get();
connected = true;
s.
request(
Operators.
unboundedOrPrefetch(
prefetch));
}
}
@
Override
public void
onNext(T
t) {
if (
done) {
Operators.
onNextDropped(
t,
context);
return;
}
if (
sourceMode !=
Fuseable.
ASYNC) {
if (!
queue.
offer(
t)) {
onError(
Operators.
onOperatorError(
s,
Exceptions.
failWithOverflow(
Exceptions.
BACKPRESSURE_ERROR_QUEUE_FULL),
t,
context));
return;
}
}
drain();
}
@
Override
public void
onError(
Throwable t) {
if (
done) {
Operators.
onErrorDropped(
t,
context);
return;
}
error =
t;
done = true;
drain();
}
@
Override
public void
onComplete() {
done = true;
drain();
}
void
drain() {
if (
WIP.
getAndIncrement(this) != 0) {
return;
}
if (
sourceMode ==
Fuseable.
SYNC) {
drainSync();
}
else {
drainAsync();
}
}
@
SuppressWarnings("unchecked")
void
drainSync() {
int
missed = 1;
for (; ; ) {
if (
connected) {
if (
s ==
Operators.
cancelledSubscription()) {
queue.
clear();
return;
}
final
Queue<T>
queue = this.
queue;
PublishMulticastInner<T>[]
a =
subscribers;
int
n =
a.length;
if (
n != 0) {
long
r =
Long.
MAX_VALUE;
long
u;
for (int
i = 0;
i <
n;
i++) {
u =
a[
i].
requested;
if (
u !=
Long.
MIN_VALUE) {
r =
Math.
min(
r,
u);
}
}
long
e = 0L;
while (
e !=
r) {
if (
s ==
Operators.
cancelledSubscription()) {
queue.
clear();
return;
}
T
v;
try {
v =
queue.
poll();
}
catch (
Throwable ex) {
error =
Operators.
onOperatorError(
s,
ex,
context);
queue.
clear();
a =
SUBSCRIBERS.
getAndSet(this,
TERMINATED);
n =
a.length;
for (int
i = 0;
i <
n;
i++) {
a[
i].
actual.
onError(
ex);
}
return;
}
if (
v == null) {
a =
SUBSCRIBERS.
getAndSet(this,
TERMINATED);
n =
a.length;
for (int
i = 0;
i <
n;
i++) {
a[
i].
actual.
onComplete();
}
return;
}
for (int
i = 0;
i <
n;
i++) {
a[
i].
actual.
onNext(
v);
}
e++;
}
if (
s ==
Operators.
cancelledSubscription()) {
queue.
clear();
return;
}
if (
queue.
isEmpty()) {
a =
SUBSCRIBERS.
getAndSet(this,
TERMINATED);
n =
a.length;
for (int
i = 0;
i <
n;
i++) {
a[
i].
actual.
onComplete();
}
return;
}
if (
e != 0L) {
for (int
i = 0;
i <
n;
i++) {
a[
i].
produced(
e);
}
}
}
}
missed =
WIP.
addAndGet(this, -
missed);
if (
missed == 0) {
break;
}
}
}
@
SuppressWarnings("unchecked")
void
drainAsync() {
int
missed = 1;
int
p =
produced;
for (; ; ) {
if (
connected) {
if (
s ==
Operators.
cancelledSubscription()) {
queue.
clear();
return;
}
final
Queue<T>
queue = this.
queue;
PublishMulticastInner<T>[]
a =
subscribers;
int
n =
a.length;
if (
n != 0) {
long
r =
Long.
MAX_VALUE;
long
u;
for (int
i = 0;
i <
n;
i++) {
u =
a[
i].
requested;
if (
u !=
Long.
MIN_VALUE) {
r =
Math.
min(
r,
u);
}
}
long
e = 0L;
while (
e !=
r) {
if (
s ==
Operators.
cancelledSubscription()) {
queue.
clear();
return;
}
boolean
d =
done;
T
v;
try {
v =
queue.
poll();
}
catch (
Throwable ex) {
queue.
clear();
error =
Operators.
onOperatorError(
s,
ex,
context);
a =
SUBSCRIBERS.
getAndSet(this,
TERMINATED);
n =
a.length;
for (int
i = 0;
i <
n;
i++) {
a[
i].
actual.
onError(
ex);
}
return;
}
boolean
empty =
v == null;
if (
d) {
Throwable ex =
error;
if (
ex != null) {
queue.
clear();
a =
SUBSCRIBERS.
getAndSet(this,
TERMINATED);
n =
a.length;
for (int
i = 0;
i <
n;
i++) {
a[
i].
actual.
onError(
ex);
}
return;
}
if (
empty) {
a =
SUBSCRIBERS.
getAndSet(this,
TERMINATED);
n =
a.length;
for (int
i = 0;
i <
n;
i++) {
a[
i].
actual.
onComplete();
}
return;
}
}
if (
empty) {
break;
}
for (int
i = 0;
i <
n;
i++) {
a[
i].
actual.
onNext(
v);
}
e++;
if (++
p ==
limit) {
s.
request(
p);
p = 0;
}
}
if (
e ==
r) {
if (
s ==
Operators.
cancelledSubscription()) {
queue.
clear();
return;
}
boolean
d =
done;
if (
d) {
Throwable ex =
error;
if (
ex != null) {
queue.
clear();
a =
SUBSCRIBERS.
getAndSet(this,
TERMINATED);
n =
a.length;
for (int
i = 0;
i <
n;
i++) {
a[
i].
actual.
onError(
ex);
}
return;
}
if (
queue.
isEmpty()) {
a =
SUBSCRIBERS.
getAndSet(this,
TERMINATED);
n =
a.length;
for (int
i = 0;
i <
n;
i++) {
a[
i].
actual.
onComplete();
}
return;
}
}
}
if (
e != 0L) {
for (int
i = 0;
i <
n;
i++) {
a[
i].
produced(
e);
}
}
}
}
produced =
p;
missed =
WIP.
addAndGet(this, -
missed);
if (
missed == 0) {
break;
}
}
}
boolean
add(
PublishMulticastInner<T>
s) {
for (; ; ) {
PublishMulticastInner<T>[]
a =
subscribers;
if (
a ==
TERMINATED) {
return false;
}
int
n =
a.length;
@
SuppressWarnings("unchecked")
PublishMulticastInner<T>[]
b =
new
PublishMulticastInner[
n + 1];
System.
arraycopy(
a, 0,
b, 0,
n);
b[
n] =
s;
if (
SUBSCRIBERS.
compareAndSet(this,
a,
b)) {
return true;
}
}
}
@
SuppressWarnings("unchecked")
void
remove(
PublishMulticastInner<T>
s) {
for (; ; ) {
PublishMulticastInner<T>[]
a =
subscribers;
if (
a ==
TERMINATED ||
a ==
EMPTY) {
return;
}
int
n =
a.length;
int
j = -1;
for (int
i = 0;
i <
n;
i++) {
if (
a[
i] ==
s) {
j =
i;
break;
}
}
if (
j < 0) {
return;
}
PublishMulticastInner<T>[]
b;
if (
n == 1) {
b =
EMPTY;
}
else {
b = new
PublishMulticastInner[
n - 1];
System.
arraycopy(
a, 0,
b, 0,
j);
System.
arraycopy(
a,
j + 1,
b,
j,
n -
j - 1);
}
if (
SUBSCRIBERS.
compareAndSet(this,
a,
b)) {
return;
}
}
}
@
Override
@
SuppressWarnings("unchecked")
public void
terminate() {
Operators.
terminate(
S, this);
if (
WIP.
getAndIncrement(this) == 0) {
if (
connected) {
queue.
clear();
}
}
}
}
static final class
PublishMulticastInner<T> implements
InnerProducer<T> {
final
FluxPublishMulticaster<T>
parent;
final
CoreSubscriber<? super T>
actual;
volatile long
requested;
@
SuppressWarnings("rawtypes")
static final
AtomicLongFieldUpdater<
PublishMulticastInner>
REQUESTED =
AtomicLongFieldUpdater.
newUpdater(
PublishMulticastInner.class,
"requested");
PublishMulticastInner(
FluxPublishMulticaster<T>
parent,
CoreSubscriber<? super T>
actual) {
this.
parent =
parent;
this.
actual =
actual;
}
@
Override
@
Nullable
public
Object scanUnsafe(
Attr key) {
if (
key ==
Attr.
REQUESTED_FROM_DOWNSTREAM) {
return
Math.
max(0L,
requested);
}
if (
key ==
Attr.
PARENT) {
return
parent;
}
if (
key ==
Attr.
CANCELLED) {
return
Long.
MIN_VALUE ==
requested;
}
return
InnerProducer.super.scanUnsafe(
key);
}
@
Override
public
CoreSubscriber<? super T>
actual() {
return
actual;
}
@
Override
public void
request(long
n) {
if (
Operators.
validate(
n)) {
Operators.
addCapCancellable(
REQUESTED, this,
n);
parent.
drain();
}
}
@
Override
public void
cancel() {
if (
REQUESTED.
getAndSet(this,
Long.
MIN_VALUE) !=
Long.
MIN_VALUE) {
parent.
remove(this);
parent.
drain();
}
}
void
produced(long
n) {
Operators.
producedCancellable(
REQUESTED, this,
n);
}
}
interface
PublishMulticasterParent {
void
terminate();
}
static final class
CancelMulticaster<T>
implements
InnerOperator<T, T>,
QueueSubscription<T> {
final
CoreSubscriber<? super T>
actual;
final
PublishMulticasterParent parent;
Subscription s;
CancelMulticaster(
CoreSubscriber<? super T>
actual,
PublishMulticasterParent parent) {
this.
actual =
actual;
this.
parent =
parent;
}
@
Override
public
CoreSubscriber<? super T>
actual() {
return
actual;
}
@
Override
@
Nullable
public
Object scanUnsafe(
Attr key) {
if (
key ==
Attr.
PARENT) {
return
s;
}
return
InnerOperator.super.scanUnsafe(
key);
}
@
Override
public void
request(long
n) {
s.
request(
n);
}
@
Override
public void
cancel() {
s.
cancel();
parent.
terminate();
}
@
Override
public void
onSubscribe(
Subscription s) {
if (
Operators.
validate(this.
s,
s)) {
this.
s =
s;
actual.
onSubscribe(this);
}
}
@
Override
public void
onNext(T
t) {
actual.
onNext(
t);
}
@
Override
public void
onError(
Throwable t) {
actual.
onError(
t);
parent.
terminate();
}
@
Override
public void
onComplete() {
actual.
onComplete();
parent.
terminate();
}
@
Override
public int
requestFusion(int
requestedMode) {
return
NONE;
}
@
Override
public void
clear() {
// should not be called because fusion is always rejected
}
@
Override
public boolean
isEmpty() {
// should not be called because fusion is always rejected
return false;
}
@
Override
public int
size() {
// should not be called because fusion is always rejected
return 0;
}
@
Override
@
Nullable
public T
poll() {
// should not be called because fusion is always rejected
return null;
}
}
static final class
CancelFuseableMulticaster<T>
implements
InnerOperator<T, T>,
QueueSubscription<T> {
final
CoreSubscriber<? super T>
actual;
final
PublishMulticasterParent parent;
QueueSubscription<T>
s;
CancelFuseableMulticaster(
CoreSubscriber<? super T>
actual,
PublishMulticasterParent parent) {
this.
actual =
actual;
this.
parent =
parent;
}
@
Override
public
CoreSubscriber<? super T>
actual() {
return
actual;
}
@
Override
@
Nullable
public
Object scanUnsafe(
Attr key) {
if (
key ==
Attr.
PARENT) {
return
s;
}
return
InnerOperator.super.scanUnsafe(
key);
}
@
Override
public void
request(long
n) {
s.
request(
n);
}
@
Override
public void
cancel() {
s.
cancel();
parent.
terminate();
}
@
SuppressWarnings("unchecked")
@
Override
public void
onSubscribe(
Subscription s) {
if (
Operators.
validate(this.
s,
s)) {
this.
s =
Operators.
as(
s);
actual.
onSubscribe(this);
}
}
@
Override
public void
onNext(T
t) {
actual.
onNext(
t);
}
@
Override
public void
onError(
Throwable t) {
actual.
onError(
t);
parent.
terminate();
}
@
Override
public void
onComplete() {
actual.
onComplete();
parent.
terminate();
}
@
Override
public int
requestFusion(int
requestedMode) {
return
s.
requestFusion(
requestedMode);
}
@
Override
@
Nullable
public T
poll() {
return
s.
poll();
}
@
Override
public boolean
isEmpty() {
return
s.
isEmpty();
}
@
Override
public int
size() {
return
s.
size();
}
@
Override
public void
clear() {
s.
clear();
}
}
}