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/**
* 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.atomic.*;
import org.reactivestreams.*;
import io.reactivex.*;
import io.reactivex.disposables.*;
import io.reactivex.exceptions.Exceptions;
import io.reactivex.functions.Function;
import io.reactivex.internal.disposables.DisposableHelper;
import io.reactivex.internal.functions.ObjectHelper;
import io.reactivex.internal.queue.SpscLinkedArrayQueue;
import io.reactivex.internal.subscriptions.SubscriptionHelper;
import io.reactivex.internal.util.*;
import io.reactivex.plugins.RxJavaPlugins;
/**
* Maps upstream values into SingleSources and merges their signals into one sequence.
* @param the source value type
* @param the result value type
*/
public final class FlowableFlatMapSingle extends AbstractFlowableWithUpstream {
final Function> mapper;
final boolean delayErrors;
final int maxConcurrency;
public FlowableFlatMapSingle(Flowable source, Function> mapper,
boolean delayError, int maxConcurrency) {
super(source);
this.mapper = mapper;
this.delayErrors = delayError;
this.maxConcurrency = maxConcurrency;
}
@Override
protected void subscribeActual(Subscriber s) {
source.subscribe(new FlatMapSingleSubscriber(s, mapper, delayErrors, maxConcurrency));
}
static final class FlatMapSingleSubscriber
extends AtomicInteger
implements FlowableSubscriber, Subscription {
private static final long serialVersionUID = 8600231336733376951L;
final Subscriber downstream;
final boolean delayErrors;
final int maxConcurrency;
final AtomicLong requested;
final CompositeDisposable set;
final AtomicInteger active;
final AtomicThrowable errors;
final Function> mapper;
final AtomicReference> queue;
Subscription upstream;
volatile boolean cancelled;
FlatMapSingleSubscriber(Subscriber actual,
Function> mapper, boolean delayErrors, int maxConcurrency) {
this.downstream = actual;
this.mapper = mapper;
this.delayErrors = delayErrors;
this.maxConcurrency = maxConcurrency;
this.requested = new AtomicLong();
this.set = new CompositeDisposable();
this.errors = new AtomicThrowable();
this.active = new AtomicInteger(1);
this.queue = new AtomicReference>();
}
@Override
public void onSubscribe(Subscription s) {
if (SubscriptionHelper.validate(this.upstream, s)) {
this.upstream = s;
downstream.onSubscribe(this);
int m = maxConcurrency;
if (m == Integer.MAX_VALUE) {
s.request(Long.MAX_VALUE);
} else {
s.request(maxConcurrency);
}
}
}
@Override
public void onNext(T t) {
SingleSource ms;
try {
ms = ObjectHelper.requireNonNull(mapper.apply(t), "The mapper returned a null SingleSource");
} catch (Throwable ex) {
Exceptions.throwIfFatal(ex);
upstream.cancel();
onError(ex);
return;
}
active.getAndIncrement();
InnerObserver inner = new InnerObserver();
if (!cancelled && set.add(inner)) {
ms.subscribe(inner);
}
}
@Override
public void onError(Throwable t) {
active.decrementAndGet();
if (errors.addThrowable(t)) {
if (!delayErrors) {
set.dispose();
}
drain();
} else {
RxJavaPlugins.onError(t);
}
}
@Override
public void onComplete() {
active.decrementAndGet();
drain();
}
@Override
public void cancel() {
cancelled = true;
upstream.cancel();
set.dispose();
}
@Override
public void request(long n) {
if (SubscriptionHelper.validate(n)) {
BackpressureHelper.add(requested, n);
drain();
}
}
void innerSuccess(InnerObserver inner, R value) {
set.delete(inner);
if (get() == 0 && compareAndSet(0, 1)) {
boolean d = active.decrementAndGet() == 0;
if (requested.get() != 0) {
downstream.onNext(value);
SpscLinkedArrayQueue q = queue.get();
if (d && (q == null || q.isEmpty())) {
Throwable ex = errors.terminate();
if (ex != null) {
downstream.onError(ex);
} else {
downstream.onComplete();
}
return;
}
BackpressureHelper.produced(requested, 1);
if (maxConcurrency != Integer.MAX_VALUE) {
upstream.request(1);
}
} else {
SpscLinkedArrayQueue q = getOrCreateQueue();
synchronized (q) {
q.offer(value);
}
}
if (decrementAndGet() == 0) {
return;
}
} else {
SpscLinkedArrayQueue q = getOrCreateQueue();
synchronized (q) {
q.offer(value);
}
active.decrementAndGet();
if (getAndIncrement() != 0) {
return;
}
}
drainLoop();
}
SpscLinkedArrayQueue getOrCreateQueue() {
for (;;) {
SpscLinkedArrayQueue current = queue.get();
if (current != null) {
return current;
}
current = new SpscLinkedArrayQueue(Flowable.bufferSize());
if (queue.compareAndSet(null, current)) {
return current;
}
}
}
void innerError(InnerObserver inner, Throwable e) {
set.delete(inner);
if (errors.addThrowable(e)) {
if (!delayErrors) {
upstream.cancel();
set.dispose();
} else {
if (maxConcurrency != Integer.MAX_VALUE) {
upstream.request(1);
}
}
active.decrementAndGet();
drain();
} else {
RxJavaPlugins.onError(e);
}
}
void drain() {
if (getAndIncrement() == 0) {
drainLoop();
}
}
void clear() {
SpscLinkedArrayQueue q = queue.get();
if (q != null) {
q.clear();
}
}
void drainLoop() {
int missed = 1;
Subscriber a = downstream;
AtomicInteger n = active;
AtomicReference> qr = queue;
for (;;) {
long r = requested.get();
long e = 0L;
while (e != r) {
if (cancelled) {
clear();
return;
}
if (!delayErrors) {
Throwable ex = errors.get();
if (ex != null) {
ex = errors.terminate();
clear();
a.onError(ex);
return;
}
}
boolean d = n.get() == 0;
SpscLinkedArrayQueue q = qr.get();
R v = q != null ? q.poll() : null;
boolean empty = v == null;
if (d && empty) {
Throwable ex = errors.terminate();
if (ex != null) {
a.onError(ex);
} else {
a.onComplete();
}
return;
}
if (empty) {
break;
}
a.onNext(v);
e++;
}
if (e == r) {
if (cancelled) {
clear();
return;
}
if (!delayErrors) {
Throwable ex = errors.get();
if (ex != null) {
ex = errors.terminate();
clear();
a.onError(ex);
return;
}
}
boolean d = n.get() == 0;
SpscLinkedArrayQueue q = qr.get();
boolean empty = q == null || q.isEmpty();
if (d && empty) {
Throwable ex = errors.terminate();
if (ex != null) {
a.onError(ex);
} else {
a.onComplete();
}
return;
}
}
if (e != 0L) {
BackpressureHelper.produced(requested, e);
if (maxConcurrency != Integer.MAX_VALUE) {
upstream.request(e);
}
}
missed = addAndGet(-missed);
if (missed == 0) {
break;
}
}
}
final class InnerObserver extends AtomicReference
implements SingleObserver, Disposable {
private static final long serialVersionUID = -502562646270949838L;
@Override
public void onSubscribe(Disposable d) {
DisposableHelper.setOnce(this, d);
}
@Override
public void onSuccess(R value) {
innerSuccess(this, value);
}
@Override
public void onError(Throwable e) {
innerError(this, e);
}
@Override
public boolean isDisposed() {
return DisposableHelper.isDisposed(get());
}
@Override
public void dispose() {
DisposableHelper.dispose(this);
}
}
}
}