/**
* 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.internal.operators.flowable;
import java.util.concurrent.Callable;
import java.util.concurrent.atomic.*;
import org.reactivestreams.*;
import io.reactivex.*;
import io.reactivex.disposables.Disposable;
import io.reactivex.exceptions.*;
import io.reactivex.functions.Function;
import io.reactivex.internal.functions.ObjectHelper;
import io.reactivex.internal.fuseable.*;
import io.reactivex.internal.queue.*;
import io.reactivex.internal.subscriptions.SubscriptionHelper;
import io.reactivex.internal.util.*;
import io.reactivex.plugins.RxJavaPlugins;
public final class FlowableFlatMap<T, U> extends AbstractFlowableWithUpstream<T, U> {
final Function<? super T, ? extends Publisher<? extends U>> mapper;
final boolean delayErrors;
final int maxConcurrency;
final int bufferSize;
public FlowableFlatMap(Flowable<T> source,
Function<? super T, ? extends Publisher<? extends U>> 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<? super U> s) {
if (FlowableScalarXMap.tryScalarXMapSubscribe(source, s, mapper)) {
return;
}
source.subscribe(subscribe(s, mapper, delayErrors, maxConcurrency, bufferSize));
}
public static <T, U> FlowableSubscriber<T> subscribe(Subscriber<? super U> s,
Function<? super T, ? extends Publisher<? extends U>> mapper,
boolean delayErrors, int maxConcurrency, int bufferSize) {
return new MergeSubscriber<T, U>(s, mapper, delayErrors, maxConcurrency, bufferSize);
}
static final class MergeSubscriber<T, U> extends AtomicInteger implements FlowableSubscriber<T>, Subscription {
private static final long serialVersionUID = -2117620485640801370L;
final Subscriber<? super U> actual;
final Function<? super T, ? extends Publisher<? extends U>> mapper;
final boolean delayErrors;
final int maxConcurrency;
final int bufferSize;
volatile SimplePlainQueue<U> queue;
volatile boolean done;
final AtomicThrowable errs = new AtomicThrowable();
volatile boolean cancelled;
final AtomicReference<InnerSubscriber<?, ?>[]> subscribers = new AtomicReference<InnerSubscriber<?, ?>[]>();
static final InnerSubscriber<?, ?>[] EMPTY = new InnerSubscriber<?, ?>[0];
static final InnerSubscriber<?, ?>[] CANCELLED = new InnerSubscriber<?, ?>[0];
final AtomicLong requested = new AtomicLong();
Subscription s;
long uniqueId;
long lastId;
int lastIndex;
int scalarEmitted;
final int scalarLimit;
MergeSubscriber(Subscriber<? super U> actual, Function<? super T, ? extends Publisher<? extends U>> mapper,
boolean delayErrors, int maxConcurrency, int bufferSize) {
this.actual = 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.s, s)) {
this.s = s;
actual.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<? extends U> p;
try {
p = ObjectHelper.requireNonNull(mapper.apply(t), "The mapper returned a null Publisher");
} catch (Throwable e) {
Exceptions.throwIfFatal(e);
s.cancel();
onError(e);
return;
}
if (p instanceof Callable) {
U u;
try {
u = ((Callable<U>)p).call();
} catch (Throwable ex) {
Exceptions.throwIfFatal(ex);
errs.addThrowable(ex);
drain();
return;
}
if (u != null) {
tryEmitScalar(u);
} else {
if (maxConcurrency != Integer.MAX_VALUE && !cancelled
&& ++scalarEmitted == scalarLimit) {
scalarEmitted = 0;
s.request(scalarLimit);
}
}
} else {
InnerSubscriber<T, U> inner = new InnerSubscriber<T, U>(this, uniqueId++);
if (addInner(inner)) {
p.subscribe(inner);
}
}
}
boolean addInner(InnerSubscriber<T, U> 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<T, U> inner) {
for (;;) {
InnerSubscriber<?, ?>[] a = subscribers.get();
if (a == CANCELLED || a == EMPTY) {
return;
}
int n = a.length;
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<U> getMainQueue() {
SimplePlainQueue<U> q = queue;
if (q == null) {
if (maxConcurrency == Integer.MAX_VALUE) {
q = new SpscLinkedArrayQueue<U>(bufferSize);
} else {
q = new SpscArrayQueue<U>(maxConcurrency);
}
queue = q;
}
return q;
}
void tryEmitScalar(U value) {
if (get() == 0 && compareAndSet(0, 1)) {
long r = requested.get();
SimpleQueue<U> q = queue;
if (r != 0L && (q == null || q.isEmpty())) {
actual.onNext(value);
if (r != Long.MAX_VALUE) {
requested.decrementAndGet();
}
if (maxConcurrency != Integer.MAX_VALUE && !cancelled
&& ++scalarEmitted == scalarLimit) {
scalarEmitted = 0;
s.request(scalarLimit);
}
} else {
if (q == null) {
q = getMainQueue();
}
if (!q.offer(value)) {
onError(new IllegalStateException("Scalar queue full?!"));
return;
}
}
if (decrementAndGet() == 0) {
return;
}
} else {
SimpleQueue<U> q = getMainQueue();
if (!q.offer(value)) {
onError(new IllegalStateException("Scalar queue full?!"));
return;
}
if (getAndIncrement() != 0) {
return;
}
}
drainLoop();
}
SimpleQueue<U> getInnerQueue(InnerSubscriber<T, U> inner) {
SimpleQueue<U> q = inner.queue;
if (q == null) {
q = new SpscArrayQueue<U>(bufferSize);
inner.queue = q;
}
return q;
}
void tryEmit(U value, InnerSubscriber<T, U> inner) {
if (get() == 0 && compareAndSet(0, 1)) {
long r = requested.get();
SimpleQueue<U> q = inner.queue;
if (r != 0L && (q == null || q.isEmpty())) {
actual.onNext(value);
if (r != Long.MAX_VALUE) {
requested.decrementAndGet();
}
inner.requestMore(1);
} else {
if (q == null) {
q = getInnerQueue(inner);
}
if (!q.offer(value)) {
onError(new MissingBackpressureException("Inner queue full?!"));
return;
}
}
if (decrementAndGet() == 0) {
return;
}
} else {
SimpleQueue<U> q = inner.queue;
if (q == null) {
q = new SpscArrayQueue<U>(bufferSize);
inner.queue = q;
}
if (!q.offer(value)) {
onError(new MissingBackpressureException("Inner queue full?!"));
return;
}
if (getAndIncrement() != 0) {
return;
}
}
drainLoop();
}
@Override
public void onError(Throwable t) {
// safeguard against misbehaving sources
if (done) {
RxJavaPlugins.onError(t);
return;
}
if (errs.addThrowable(t)) {
done = true;
drain();
} else {
RxJavaPlugins.onError(t);
}
}
@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;
s.cancel();
disposeAll();
if (getAndIncrement() == 0) {
SimpleQueue<U> q = queue;
if (q != null) {
q.clear();
}
}
}
}
void drain() {
if (getAndIncrement() == 0) {
drainLoop();
}
}
void drainLoop() {
final Subscriber<? super U> child = this.actual;
int missed = 1;
for (;;) {
if (checkTerminate()) {
return;
}
SimplePlainQueue<U> svq = queue;
long r = requested.get();
boolean unbounded = r == Long.MAX_VALUE;
long replenishMain = 0;
if (svq != null) {
for (;;) {
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);
}
}
if (r == 0L || o == null) {
break;
}
}
}
boolean d = done;
svq = queue;
InnerSubscriber<?, ?>[] inner = subscribers.get();
int n = inner.length;
if (d && (svq == null || svq.isEmpty()) && n == 0) {
Throwable ex = errs.terminate();
if (ex != ExceptionHelper.TERMINATED) {
if (ex == null) {
child.onComplete();
} else {
child.onError(ex);
}
}
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<T, U> is = (InnerSubscriber<T, U>)inner[j];
U o = null;
for (;;) {
if (checkTerminate()) {
return;
}
SimpleQueue<U> q = is.queue;
if (q == null) {
break;
}
long produced = 0;
while (r != 0L) {
try {
o = q.poll();
} catch (Throwable ex) {
Exceptions.throwIfFatal(ex);
is.dispose();
errs.addThrowable(ex);
if (checkTerminate()) {
return;
}
removeInner(is);
innerCompleted = true;
i++;
continue sourceLoop;
}
if (o == null) {
break;
}
child.onNext(o);
if (checkTerminate()) {
return;
}
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<U> 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) {
s.request(replenishMain);
}
if (innerCompleted) {
continue;
}
missed = addAndGet(-missed);
if (missed == 0) {
break;
}
}
}
boolean checkTerminate() {
if (cancelled) {
clearScalarQueue();
return true;
}
if (!delayErrors && errs.get() != null) {
clearScalarQueue();
Throwable ex = errs.terminate();
if (ex != ExceptionHelper.TERMINATED) {
actual.onError(ex);
}
return true;
}
return false;
}
void clearScalarQueue() {
SimpleQueue<U> q = queue;
if (q != null) {
q.clear();
}
}
void disposeAll() {
InnerSubscriber<?, ?>[] a = subscribers.get();
if (a != CANCELLED) {
a = subscribers.getAndSet(CANCELLED);
if (a != CANCELLED) {
for (InnerSubscriber<?, ?> inner : a) {
inner.dispose();
}
Throwable ex = errs.terminate();
if (ex != null && ex != ExceptionHelper.TERMINATED) {
RxJavaPlugins.onError(ex);
}
}
}
}
void innerError(InnerSubscriber<T, U> inner, Throwable t) {
if (errs.addThrowable(t)) {
inner.done = true;
if (!delayErrors) {
s.cancel();
for (InnerSubscriber<?, ?> a : subscribers.getAndSet(CANCELLED)) {
a.dispose();
}
}
drain();
} else {
RxJavaPlugins.onError(t);
}
}
}
static final class InnerSubscriber<T, U> extends AtomicReference<Subscription>
implements FlowableSubscriber<U>, Disposable {
private static final long serialVersionUID = -4606175640614850599L;
final long id;
final MergeSubscriber<T, U> parent;
final int limit;
final int bufferSize;
volatile boolean done;
volatile SimpleQueue<U> queue;
long produced;
int fusionMode;
InnerSubscriber(MergeSubscriber<T, U> parent, long id) {
this.id = id;
this.parent = parent;
this.bufferSize = parent.bufferSize;
this.limit = bufferSize >> 2;
}
@Override
public void onSubscribe(Subscription s) {
if (SubscriptionHelper.setOnce(this, s)) {
if (s instanceof QueueSubscription) {
@SuppressWarnings("unchecked")
QueueSubscription<U> qs = (QueueSubscription<U>) 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;
}
}
}