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Reactive Extensions for Java
/*
* Copyright (c) 2016-present, RxJava Contributors.
*
* 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 io.reactivex.rxjava3.internal.operators.flowable;
import java.util.Objects;
import java.util.concurrent.atomic.*;
import org.reactivestreams.*;
import io.reactivex.rxjava3.core.*;
import io.reactivex.rxjava3.disposables.Disposable;
import io.reactivex.rxjava3.exceptions.*;
import io.reactivex.rxjava3.functions.*;
import io.reactivex.rxjava3.internal.subscriptions.SubscriptionHelper;
import io.reactivex.rxjava3.internal.util.*;
import io.reactivex.rxjava3.operators.*;
import io.reactivex.rxjava3.plugins.RxJavaPlugins;
public final class FlowableFlatMap extends AbstractFlowableWithUpstream {
final Function> mapper;
final boolean delayErrors;
final int maxConcurrency;
final int bufferSize;
public FlowableFlatMap(Flowable source,
Function> mapper,
boolean delayErrors, int maxConcurrency, int bufferSize) {
super(source);
this.mapper = mapper;
this.delayErrors = delayErrors;
this.maxConcurrency = maxConcurrency;
this.bufferSize = bufferSize;
}
@Override
protected void subscribeActual(Subscriber s) {
if (FlowableScalarXMap.tryScalarXMapSubscribe(source, s, mapper)) {
return;
}
source.subscribe(subscribe(s, mapper, delayErrors, maxConcurrency, bufferSize));
}
public static FlowableSubscriber subscribe(Subscriber s,
Function> mapper,
boolean delayErrors, int maxConcurrency, int bufferSize) {
return new MergeSubscriber<>(s, mapper, delayErrors, maxConcurrency, bufferSize);
}
static final class MergeSubscriber extends AtomicInteger implements FlowableSubscriber, Subscription {
private static final long serialVersionUID = -2117620485640801370L;
final Subscriber downstream;
final Function> mapper;
final boolean delayErrors;
final int maxConcurrency;
final int bufferSize;
volatile SimplePlainQueue queue;
volatile boolean done;
final AtomicThrowable errors = new AtomicThrowable();
volatile boolean cancelled;
final AtomicReference[]> subscribers = new AtomicReference<>();
static final InnerSubscriber[] EMPTY = new InnerSubscriber[0];
static final InnerSubscriber[] CANCELLED = new InnerSubscriber[0];
final AtomicLong requested = new AtomicLong();
Subscription upstream;
long uniqueId;
long lastId;
int lastIndex;
int scalarEmitted;
final int scalarLimit;
MergeSubscriber(Subscriber actual, Function> mapper,
boolean delayErrors, int maxConcurrency, int bufferSize) {
this.downstream = actual;
this.mapper = mapper;
this.delayErrors = delayErrors;
this.maxConcurrency = maxConcurrency;
this.bufferSize = bufferSize;
this.scalarLimit = Math.max(1, maxConcurrency >> 1);
subscribers.lazySet(EMPTY);
}
@Override
public void onSubscribe(Subscription s) {
if (SubscriptionHelper.validate(this.upstream, s)) {
this.upstream = s;
downstream.onSubscribe(this);
if (!cancelled) {
if (maxConcurrency == Integer.MAX_VALUE) {
s.request(Long.MAX_VALUE);
} else {
s.request(maxConcurrency);
}
}
}
}
@SuppressWarnings("unchecked")
@Override
public void onNext(T t) {
// safeguard against misbehaving sources
if (done) {
return;
}
Publisher p;
try {
p = Objects.requireNonNull(mapper.apply(t), "The mapper returned a null Publisher");
} catch (Throwable e) {
Exceptions.throwIfFatal(e);
upstream.cancel();
onError(e);
return;
}
if (p instanceof Supplier) {
U u;
try {
u = ((Supplier)p).get();
} catch (Throwable ex) {
Exceptions.throwIfFatal(ex);
errors.tryAddThrowableOrReport(ex);
drain();
return;
}
if (u != null) {
tryEmitScalar(u);
} else {
if (maxConcurrency != Integer.MAX_VALUE
&& !cancelled && ++scalarEmitted == scalarLimit) {
scalarEmitted = 0;
upstream.request(scalarLimit);
}
}
} else {
InnerSubscriber inner = new InnerSubscriber<>(this, bufferSize, uniqueId++);
if (addInner(inner)) {
p.subscribe(inner);
}
}
}
boolean addInner(InnerSubscriber inner) {
for (;;) {
InnerSubscriber[] a = subscribers.get();
if (a == CANCELLED) {
inner.dispose();
return false;
}
int n = a.length;
InnerSubscriber[] b = new InnerSubscriber[n + 1];
System.arraycopy(a, 0, b, 0, n);
b[n] = inner;
if (subscribers.compareAndSet(a, b)) {
return true;
}
}
}
void removeInner(InnerSubscriber inner) {
for (;;) {
InnerSubscriber[] a = subscribers.get();
int n = a.length;
if (n == 0) {
return;
}
int j = -1;
for (int i = 0; i < n; i++) {
if (a[i] == inner) {
j = i;
break;
}
}
if (j < 0) {
return;
}
InnerSubscriber[] b;
if (n == 1) {
b = EMPTY;
} else {
b = new InnerSubscriber[n - 1];
System.arraycopy(a, 0, b, 0, j);
System.arraycopy(a, j + 1, b, j, n - j - 1);
}
if (subscribers.compareAndSet(a, b)) {
return;
}
}
}
SimpleQueue getMainQueue() {
SimplePlainQueue q = queue;
if (q == null) {
if (maxConcurrency == Integer.MAX_VALUE) {
q = new SpscLinkedArrayQueue<>(bufferSize);
} else {
q = new SpscArrayQueue<>(maxConcurrency);
}
queue = q;
}
return q;
}
void tryEmitScalar(U value) {
if (get() == 0 && compareAndSet(0, 1)) {
long r = requested.get();
SimpleQueue q = queue;
if (r != 0L && (q == null || q.isEmpty())) {
downstream.onNext(value);
if (r != Long.MAX_VALUE) {
requested.decrementAndGet();
}
if (maxConcurrency != Integer.MAX_VALUE
&& !cancelled && ++scalarEmitted == scalarLimit) {
scalarEmitted = 0;
upstream.request(scalarLimit);
}
} else {
if (q == null) {
q = getMainQueue();
}
if (!q.offer(value)) {
onError(new QueueOverflowException());
}
}
if (decrementAndGet() == 0) {
return;
}
} else {
SimpleQueue q = getMainQueue();
if (!q.offer(value)) {
onError(new QueueOverflowException());
return;
}
if (getAndIncrement() != 0) {
return;
}
}
drainLoop();
}
void tryEmit(U value, InnerSubscriber inner) {
if (get() == 0 && compareAndSet(0, 1)) {
long r = requested.get();
SimpleQueue q = inner.queue;
if (r != 0L && (q == null || q.isEmpty())) {
downstream.onNext(value);
if (r != Long.MAX_VALUE) {
requested.decrementAndGet();
}
inner.requestMore(1);
} else {
if (q == null) {
q = new SpscArrayQueue<>(bufferSize);
inner.queue = q;
}
if (!q.offer(value)) {
onError(new QueueOverflowException());
}
}
if (decrementAndGet() == 0) {
return;
}
} else {
SimpleQueue q = inner.queue;
if (q == null) {
q = new SpscArrayQueue<>(bufferSize);
inner.queue = q;
}
if (!q.offer(value)) {
onError(new QueueOverflowException());
return;
}
if (getAndIncrement() != 0) {
return;
}
}
drainLoop();
}
@Override
public void onError(Throwable t) {
// safeguard against misbehaving sources
if (done) {
RxJavaPlugins.onError(t);
return;
}
if (errors.tryAddThrowableOrReport(t)) {
done = true;
if (!delayErrors) {
for (InnerSubscriber a : subscribers.getAndSet(CANCELLED)) {
a.dispose();
}
}
drain();
}
}
@Override
public void onComplete() {
// safeguard against misbehaving sources
if (done) {
return;
}
done = true;
drain();
}
@Override
public void request(long n) {
if (SubscriptionHelper.validate(n)) {
BackpressureHelper.add(requested, n);
drain();
}
}
@Override
public void cancel() {
if (!cancelled) {
cancelled = true;
upstream.cancel();
disposeAll();
if (getAndIncrement() == 0) {
SimpleQueue q = queue;
if (q != null) {
q.clear();
}
}
}
}
void drain() {
if (getAndIncrement() == 0) {
drainLoop();
}
}
void drainLoop() {
final Subscriber child = this.downstream;
int missed = 1;
for (;;) {
if (checkTerminate()) {
return;
}
SimplePlainQueue svq = queue;
long r = requested.get();
boolean unbounded = r == Long.MAX_VALUE;
long replenishMain = 0;
if (svq != null) {
long scalarEmission = 0;
U o = null;
while (r != 0L) {
o = svq.poll();
if (checkTerminate()) {
return;
}
if (o == null) {
break;
}
child.onNext(o);
replenishMain++;
scalarEmission++;
r--;
}
if (scalarEmission != 0L) {
if (unbounded) {
r = Long.MAX_VALUE;
} else {
r = requested.addAndGet(-scalarEmission);
}
}
}
boolean d = done;
svq = queue;
InnerSubscriber[] inner = subscribers.get();
int n = inner.length;
if (d && (svq == null || svq.isEmpty()) && n == 0) {
errors.tryTerminateConsumer(downstream);
return;
}
boolean innerCompleted = false;
if (n != 0) {
long startId = lastId;
int index = lastIndex;
if (n <= index || inner[index].id != startId) {
if (n <= index) {
index = 0;
}
int j = index;
for (int i = 0; i < n; i++) {
if (inner[j].id == startId) {
break;
}
j++;
if (j == n) {
j = 0;
}
}
index = j;
lastIndex = j;
lastId = inner[j].id;
}
int j = index;
sourceLoop:
for (int i = 0; i < n; i++) {
if (checkTerminate()) {
return;
}
@SuppressWarnings("unchecked")
InnerSubscriber is = (InnerSubscriber)inner[j];
U o = null;
for (;;) {
SimpleQueue q = is.queue;
if (q == null) {
break;
}
long produced = 0;
while (r != 0L) {
if (checkTerminate()) {
return;
}
try {
o = q.poll();
} catch (Throwable ex) {
Exceptions.throwIfFatal(ex);
is.dispose();
errors.tryAddThrowableOrReport(ex);
if (!delayErrors) {
upstream.cancel();
}
if (checkTerminate()) {
return;
}
removeInner(is);
innerCompleted = true;
i++;
continue sourceLoop;
}
if (o == null) {
break;
}
child.onNext(o);
r--;
produced++;
}
if (produced != 0L) {
if (!unbounded) {
r = requested.addAndGet(-produced);
} else {
r = Long.MAX_VALUE;
}
is.requestMore(produced);
}
if (r == 0 || o == null) {
break;
}
}
boolean innerDone = is.done;
SimpleQueue innerQueue = is.queue;
if (innerDone && (innerQueue == null || innerQueue.isEmpty())) {
removeInner(is);
if (checkTerminate()) {
return;
}
replenishMain++;
innerCompleted = true;
}
if (r == 0L) {
break;
}
j++;
if (j == n) {
j = 0;
}
}
lastIndex = j;
lastId = inner[j].id;
}
if (replenishMain != 0L && !cancelled) {
upstream.request(replenishMain);
}
if (innerCompleted) {
continue;
}
missed = addAndGet(-missed);
if (missed == 0) {
break;
}
}
}
boolean checkTerminate() {
if (cancelled) {
clearScalarQueue();
return true;
}
if (!delayErrors && errors.get() != null) {
clearScalarQueue();
errors.tryTerminateConsumer(downstream);
return true;
}
return false;
}
void clearScalarQueue() {
SimpleQueue q = queue;
if (q != null) {
q.clear();
}
}
void disposeAll() {
InnerSubscriber[] a = subscribers.getAndSet(CANCELLED);
if (a != CANCELLED) {
for (InnerSubscriber inner : a) {
inner.dispose();
}
errors.tryTerminateAndReport();
}
}
void innerError(InnerSubscriber inner, Throwable t) {
if (errors.tryAddThrowableOrReport(t)) {
inner.done = true;
if (!delayErrors) {
upstream.cancel();
for (InnerSubscriber a : subscribers.getAndSet(CANCELLED)) {
a.dispose();
}
}
drain();
}
}
}
static final class InnerSubscriber extends AtomicReference
implements FlowableSubscriber, Disposable {
private static final long serialVersionUID = -4606175640614850599L;
final long id;
final MergeSubscriber parent;
final int limit;
final int bufferSize;
volatile boolean done;
volatile SimpleQueue queue;
long produced;
int fusionMode;
InnerSubscriber(MergeSubscriber parent, int bufferSize, long id) {
this.id = id;
this.parent = parent;
this.bufferSize = bufferSize;
this.limit = bufferSize >> 2;
}
@Override
public void onSubscribe(Subscription s) {
if (SubscriptionHelper.setOnce(this, s)) {
if (s instanceof QueueSubscription) {
@SuppressWarnings("unchecked")
QueueSubscription qs = (QueueSubscription) s;
int m = qs.requestFusion(QueueSubscription.ANY | QueueSubscription.BOUNDARY);
if (m == QueueSubscription.SYNC) {
fusionMode = m;
queue = qs;
done = true;
parent.drain();
return;
}
if (m == QueueSubscription.ASYNC) {
fusionMode = m;
queue = qs;
}
}
s.request(bufferSize);
}
}
@Override
public void onNext(U t) {
if (fusionMode != QueueSubscription.ASYNC) {
parent.tryEmit(t, this);
} else {
parent.drain();
}
}
@Override
public void onError(Throwable t) {
lazySet(SubscriptionHelper.CANCELLED);
parent.innerError(this, t);
}
@Override
public void onComplete() {
done = true;
parent.drain();
}
void requestMore(long n) {
if (fusionMode != QueueSubscription.SYNC) {
long p = produced + n;
if (p >= limit) {
produced = 0;
get().request(p);
} else {
produced = p;
}
}
}
@Override
public void dispose() {
SubscriptionHelper.cancel(this);
}
@Override
public boolean isDisposed() {
return get() == SubscriptionHelper.CANCELLED;
}
}
}
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