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RxJava 3.x extra sources, operators and components and ports of many 1.x companion libraries.
/*
* Copyright 2016-2019 David Karnok
*
* 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 hu.akarnokd.rxjava3.operators;
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.*;
import io.reactivex.rxjava3.internal.disposables.DisposableHelper;
import io.reactivex.rxjava3.internal.functions.ObjectHelper;
import io.reactivex.rxjava3.internal.queue.SpscLinkedArrayQueue;
import io.reactivex.rxjava3.internal.util.AtomicThrowable;
import io.reactivex.rxjava3.plugins.RxJavaPlugins;
/**
* Maps each upstream element into the single result of an inner Observable while
* keeping the order of items and combines the original and inner item into the output
* value for the downstream.
*
* @param the upstream value type
* @param the inner Observable's element type
* @param the result element type
* @since 0.20.4
*/
final class ObservableMapAsync extends Observable
implements ObservableTransformer {
final ObservableSource source;
final Function> mapper;
final BiFunction combiner;
final int capacityHint;
ObservableMapAsync(ObservableSource source,
Function> mapper,
BiFunction combiner,
int capacityHint) {
super();
this.source = source;
this.mapper = mapper;
this.combiner = combiner;
this.capacityHint = capacityHint;
}
@Override
public ObservableSource apply(Observable upstream) {
return new ObservableMapAsync(upstream, mapper, combiner, capacityHint);
}
@Override
protected void subscribeActual(Observer observer) {
source.subscribe(new MapAsyncObserver(observer, mapper, combiner, capacityHint));
}
static final class MapAsyncObserver extends AtomicInteger implements Observer, Disposable {
private static final long serialVersionUID = -204261674817426393L;
final Observer downstream;
final Function> mapper;
final BiFunction combiner;
final SpscLinkedArrayQueue queue;
final AtomicThrowable errors;
final AtomicReference innerDisposable;
Disposable upstream;
volatile boolean done;
volatile boolean disposed;
T current;
volatile int state;
U inner;
static final int STATE_FRESH = 0;
static final int STATE_RUNNING = 1;
static final int STATE_SUCCESS = 2;
static final int STATE_EMPTY = 3;
MapAsyncObserver(
Observer downstream,
Function> mapper,
BiFunction combiner,
int capacityHint) {
this.downstream = downstream;
this.mapper = mapper;
this.combiner = combiner;
this.queue = new SpscLinkedArrayQueue(capacityHint);
this.errors = new AtomicThrowable();
this.innerDisposable = new AtomicReference();
}
@Override
public void dispose() {
disposed = true;
upstream.dispose();
DisposableHelper.dispose(innerDisposable);
errors.tryTerminateAndReport();
drain();
}
@Override
public boolean isDisposed() {
return disposed;
}
@Override
public void onSubscribe(Disposable d) {
if (DisposableHelper.validate(upstream, d)) {
this.upstream = d;
downstream.onSubscribe(this);
}
}
@Override
public void onNext(T t) {
queue.offer(t);
drain();
}
@Override
public void onError(Throwable e) {
DisposableHelper.dispose(innerDisposable);
if (errors.tryAddThrowableOrReport(e)) {
done = true;
drain();
}
}
@Override
public void onComplete() {
done = true;
drain();
}
public void drain() {
if (getAndIncrement() != 0) {
return;
}
int missed = 1;
for (;;) {
if (disposed) {
current = null;
inner = null;
queue.clear();
} else {
if (errors.get() != null) {
disposed = true;
errors.tryTerminateConsumer(downstream);
continue;
}
int s = state;
if (s == STATE_FRESH) {
boolean d = done;
T item = queue.poll();
boolean empty = item == null;
if (d && empty) {
downstream.onComplete();
} else
if (!empty) {
current = item;
ObservableSource innerSource;
try {
innerSource = ObjectHelper.requireNonNull(mapper.apply(item), "The mapper returned a null ObservableSource");
} catch (Throwable ex) {
Exceptions.throwIfFatal(ex);
disposed = true;
upstream.dispose();
errors.tryAddThrowableOrReport(ex);
errors.tryTerminateConsumer(downstream);
continue;
}
state = STATE_RUNNING;
innerSource.subscribe(new InnerObserver());
}
} else
if (s == STATE_SUCCESS) {
T mainItem = current;
current = null;
U innerItem = inner;
inner = null;
R result;
try {
result = ObjectHelper.requireNonNull(combiner.apply(mainItem, innerItem), "The combiner returned a null value");
} catch (Throwable ex) {
Exceptions.throwIfFatal(ex);
disposed = true;
upstream.dispose();
errors.tryAddThrowableOrReport(ex);
errors.tryTerminateConsumer(downstream);
continue;
}
downstream.onNext(result);
state = STATE_FRESH;
continue;
} else
if (s == STATE_EMPTY) {
current = null;
state = STATE_FRESH;
continue;
}
}
missed = addAndGet(-missed);
if (missed == 0) {
break;
}
}
}
void innerSuccess(U item) {
inner = item;
state = STATE_SUCCESS;
DisposableHelper.replace(innerDisposable, null);
drain();
}
void innerError(Throwable ex) {
if (errors.tryAddThrowableOrReport(ex)) {
state = STATE_EMPTY;
DisposableHelper.replace(innerDisposable, null);
upstream.dispose();
drain();
}
}
void innerComplete() {
state = STATE_EMPTY;
DisposableHelper.replace(innerDisposable, null);
drain();
}
final class InnerObserver implements Observer {
boolean once;
@Override
public void onSubscribe(Disposable d) {
DisposableHelper.setOnce(innerDisposable, d);
}
@Override
public void onNext(U t) {
if (!once) {
once = true;
innerDisposable.get().dispose();
innerSuccess(t);
}
}
@Override
public void onError(Throwable e) {
if (!once) {
innerError(e);
} else {
RxJavaPlugins.onError(e);
}
}
@Override
public void onComplete() {
if (!once) {
innerComplete();
}
}
}
}
}