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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.observable;
import java.util.Objects;
import java.util.concurrent.atomic.*;
import io.reactivex.rxjava3.core.*;
import io.reactivex.rxjava3.disposables.Disposable;
import io.reactivex.rxjava3.exceptions.Exceptions;
import io.reactivex.rxjava3.functions.Function;
import io.reactivex.rxjava3.internal.disposables.DisposableHelper;
import io.reactivex.rxjava3.internal.util.AtomicThrowable;
import io.reactivex.rxjava3.operators.QueueDisposable;
import io.reactivex.rxjava3.operators.SimpleQueue;
import io.reactivex.rxjava3.operators.SpscLinkedArrayQueue;
import io.reactivex.rxjava3.plugins.RxJavaPlugins;
public final class ObservableSwitchMap extends AbstractObservableWithUpstream {
final Function> mapper;
final int bufferSize;
final boolean delayErrors;
public ObservableSwitchMap(ObservableSource source,
Function> mapper, int bufferSize,
boolean delayErrors) {
super(source);
this.mapper = mapper;
this.bufferSize = bufferSize;
this.delayErrors = delayErrors;
}
@Override
public void subscribeActual(Observer t) {
if (ObservableScalarXMap.tryScalarXMapSubscribe(source, t, mapper)) {
return;
}
source.subscribe(new SwitchMapObserver<>(t, mapper, bufferSize, delayErrors));
}
static final class SwitchMapObserver extends AtomicInteger implements Observer, Disposable {
private static final long serialVersionUID = -3491074160481096299L;
final Observer downstream;
final Function> mapper;
final int bufferSize;
final boolean delayErrors;
final AtomicThrowable errors;
volatile boolean done;
volatile boolean cancelled;
Disposable upstream;
final AtomicReference> active = new AtomicReference<>();
static final SwitchMapInnerObserver CANCELLED;
static {
CANCELLED = new SwitchMapInnerObserver<>(null, -1L, 1);
CANCELLED.cancel();
}
volatile long unique;
SwitchMapObserver(Observer actual,
Function> mapper, int bufferSize,
boolean delayErrors) {
this.downstream = actual;
this.mapper = mapper;
this.bufferSize = bufferSize;
this.delayErrors = delayErrors;
this.errors = new AtomicThrowable();
}
@Override
public void onSubscribe(Disposable d) {
if (DisposableHelper.validate(this.upstream, d)) {
this.upstream = d;
downstream.onSubscribe(this);
}
}
@Override
public void onNext(T t) {
long c = unique + 1;
unique = c;
SwitchMapInnerObserver inner = active.get();
if (inner != null) {
inner.cancel();
}
ObservableSource p;
try {
p = Objects.requireNonNull(mapper.apply(t), "The ObservableSource returned is null");
} catch (Throwable e) {
Exceptions.throwIfFatal(e);
upstream.dispose();
onError(e);
return;
}
SwitchMapInnerObserver nextInner = new SwitchMapInnerObserver<>(this, c, bufferSize);
for (;;) {
inner = active.get();
if (inner == CANCELLED) {
break;
}
if (active.compareAndSet(inner, nextInner)) {
p.subscribe(nextInner);
break;
}
}
}
@Override
public void onError(Throwable t) {
if (!done && errors.tryAddThrowable(t)) {
if (!delayErrors) {
disposeInner();
}
done = true;
drain();
} else {
RxJavaPlugins.onError(t);
}
}
@Override
public void onComplete() {
if (!done) {
done = true;
drain();
}
}
@Override
public void dispose() {
if (!cancelled) {
cancelled = true;
upstream.dispose();
disposeInner();
errors.tryTerminateAndReport();
}
}
@Override
public boolean isDisposed() {
return cancelled;
}
@SuppressWarnings("unchecked")
void disposeInner() {
SwitchMapInnerObserver a = active.getAndSet((SwitchMapInnerObserver)CANCELLED);
if (a != null) {
a.cancel();
}
}
void drain() {
if (getAndIncrement() != 0) {
return;
}
final Observer a = downstream;
final AtomicReference> active = this.active;
final boolean delayErrors = this.delayErrors;
int missing = 1;
for (;;) {
if (cancelled) {
return;
}
if (done) {
boolean empty = active.get() == null;
if (delayErrors) {
if (empty) {
Throwable ex = errors.get();
if (ex != null) {
a.onError(ex);
} else {
a.onComplete();
}
return;
}
} else {
Throwable ex = errors.get();
if (ex != null) {
errors.tryTerminateConsumer(a);
return;
}
if (empty) {
a.onComplete();
return;
}
}
}
SwitchMapInnerObserver inner = active.get();
if (inner != null) {
SimpleQueue q = inner.queue;
if (q != null) {
boolean retry = false;
for (;;) {
if (cancelled) {
return;
}
if (inner != active.get()) {
retry = true;
break;
}
if (!delayErrors) {
Throwable ex = errors.get();
if (ex != null) {
errors.tryTerminateConsumer(a);
return;
}
}
boolean d = inner.done;
R v;
try {
v = q.poll();
} catch (Throwable ex) {
Exceptions.throwIfFatal(ex);
errors.tryAddThrowableOrReport(ex);
active.compareAndSet(inner, null);
if (!delayErrors) {
disposeInner();
upstream.dispose();
done = true;
} else {
inner.cancel();
}
v = null;
retry = true;
}
boolean empty = v == null;
if (d && empty) {
active.compareAndSet(inner, null);
retry = true;
break;
}
if (empty) {
break;
}
a.onNext(v);
}
if (retry) {
continue;
}
}
}
missing = addAndGet(-missing);
if (missing == 0) {
break;
}
}
}
void innerError(SwitchMapInnerObserver inner, Throwable ex) {
if (inner.index == unique && errors.tryAddThrowable(ex)) {
if (!delayErrors) {
upstream.dispose();
done = true;
}
inner.done = true;
drain();
} else {
RxJavaPlugins.onError(ex);
}
}
}
static final class SwitchMapInnerObserver extends AtomicReference implements Observer {
private static final long serialVersionUID = 3837284832786408377L;
final SwitchMapObserver parent;
final long index;
final int bufferSize;
volatile SimpleQueue queue;
volatile boolean done;
SwitchMapInnerObserver(SwitchMapObserver parent, long index, int bufferSize) {
this.parent = parent;
this.index = index;
this.bufferSize = bufferSize;
}
@Override
public void onSubscribe(Disposable d) {
if (DisposableHelper.setOnce(this, d)) {
if (d instanceof QueueDisposable) {
@SuppressWarnings("unchecked")
QueueDisposable qd = (QueueDisposable) d;
int m = qd.requestFusion(QueueDisposable.ANY | QueueDisposable.BOUNDARY);
if (m == QueueDisposable.SYNC) {
queue = qd;
done = true;
parent.drain();
return;
}
if (m == QueueDisposable.ASYNC) {
queue = qd;
return;
}
}
queue = new SpscLinkedArrayQueue<>(bufferSize);
}
}
@Override
public void onNext(R t) {
SimpleQueue q = queue;
if (index == parent.unique && q != null) {
if (t != null) {
q.offer(t);
}
parent.drain();
}
}
@Override
public void onError(Throwable t) {
parent.innerError(this, t);
}
@Override
public void onComplete() {
if (index == parent.unique) {
done = true;
parent.drain();
}
}
public void cancel() {
DisposableHelper.dispose(this);
}
}
}
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