io.reactivex.rxjava3.internal.operators.mixed.FlowableConcatMapSingle Maven / Gradle / Ivy
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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.rxjava3.internal.operators.mixed;
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.Exceptions;
import io.reactivex.rxjava3.functions.Function;
import io.reactivex.rxjava3.internal.disposables.DisposableHelper;
import io.reactivex.rxjava3.internal.util.*;
import io.reactivex.rxjava3.operators.SimpleQueue;
/**
* Maps each upstream item into a {@link SingleSource}, subscribes to them one after the other terminates
* and relays their success values, optionally delaying any errors till the main and inner sources
* terminate.
* History: 2.1.11 - experimental
* @param the upstream element type
* @param the output element type
* @since 2.2
*/
public final class FlowableConcatMapSingle extends Flowable {
final Flowable source;
final Function> mapper;
final ErrorMode errorMode;
final int prefetch;
public FlowableConcatMapSingle(Flowable source,
Function> mapper,
ErrorMode errorMode, int prefetch) {
this.source = source;
this.mapper = mapper;
this.errorMode = errorMode;
this.prefetch = prefetch;
}
@Override
protected void subscribeActual(Subscriber s) {
source.subscribe(new ConcatMapSingleSubscriber<>(s, mapper, prefetch, errorMode));
}
static final class ConcatMapSingleSubscriber
extends ConcatMapXMainSubscriber implements Subscription {
private static final long serialVersionUID = -9140123220065488293L;
final Subscriber downstream;
final Function> mapper;
final AtomicLong requested;
final ConcatMapSingleObserver inner;
long emitted;
int consumed;
R item;
volatile int state;
/** No inner SingleSource is running. */
static final int STATE_INACTIVE = 0;
/** An inner SingleSource is running but there are no results yet. */
static final int STATE_ACTIVE = 1;
/** The inner SingleSource succeeded with a value in {@link #item}. */
static final int STATE_RESULT_VALUE = 2;
ConcatMapSingleSubscriber(Subscriber downstream,
Function> mapper,
int prefetch, ErrorMode errorMode) {
super(prefetch, errorMode);
this.downstream = downstream;
this.mapper = mapper;
this.requested = new AtomicLong();
this.inner = new ConcatMapSingleObserver<>(this);
}
@Override
void onSubscribeDownstream() {
downstream.onSubscribe(this);
}
@Override
public void request(long n) {
BackpressureHelper.add(requested, n);
drain();
}
@Override
public void cancel() {
stop();
}
@Override
void clearValue() {
item = null;
}
@Override
void disposeInner() {
inner.dispose();
}
void innerSuccess(R item) {
this.item = item;
this.state = STATE_RESULT_VALUE;
drain();
}
void innerError(Throwable ex) {
if (errors.tryAddThrowableOrReport(ex)) {
if (errorMode != ErrorMode.END) {
upstream.cancel();
}
this.state = STATE_INACTIVE;
drain();
}
}
@Override
void drain() {
if (getAndIncrement() != 0) {
return;
}
int missed = 1;
Subscriber downstream = this.downstream;
ErrorMode errorMode = this.errorMode;
SimpleQueue queue = this.queue;
AtomicThrowable errors = this.errors;
AtomicLong requested = this.requested;
int limit = prefetch - (prefetch >> 1);
boolean syncFused = this.syncFused;
for (;;) {
for (;;) {
if (cancelled) {
queue.clear();
item = null;
break;
}
int s = state;
if (errors.get() != null) {
if (errorMode == ErrorMode.IMMEDIATE
|| (errorMode == ErrorMode.BOUNDARY && s == STATE_INACTIVE)) {
queue.clear();
item = null;
errors.tryTerminateConsumer(downstream);
return;
}
}
if (s == STATE_INACTIVE) {
boolean d = done;
T v;
try {
v = queue.poll();
} catch (Throwable ex) {
Exceptions.throwIfFatal(ex);
upstream.cancel();
errors.tryAddThrowableOrReport(ex);
errors.tryTerminateConsumer(downstream);
return;
}
boolean empty = v == null;
if (d && empty) {
errors.tryTerminateConsumer(downstream);
return;
}
if (empty) {
break;
}
if (!syncFused) {
int c = consumed + 1;
if (c == limit) {
consumed = 0;
upstream.request(limit);
} else {
consumed = c;
}
}
SingleSource ss;
try {
ss = Objects.requireNonNull(mapper.apply(v), "The mapper returned a null SingleSource");
} catch (Throwable ex) {
Exceptions.throwIfFatal(ex);
upstream.cancel();
queue.clear();
errors.tryAddThrowableOrReport(ex);
errors.tryTerminateConsumer(downstream);
return;
}
state = STATE_ACTIVE;
ss.subscribe(inner);
break;
} else if (s == STATE_RESULT_VALUE) {
long e = emitted;
if (e != requested.get()) {
R w = item;
item = null;
downstream.onNext(w);
emitted = e + 1;
state = STATE_INACTIVE;
} else {
break;
}
} else {
break;
}
}
missed = addAndGet(-missed);
if (missed == 0) {
break;
}
}
}
static final class ConcatMapSingleObserver
extends AtomicReference
implements SingleObserver {
private static final long serialVersionUID = -3051469169682093892L;
final ConcatMapSingleSubscriber parent;
ConcatMapSingleObserver(ConcatMapSingleSubscriber parent) {
this.parent = parent;
}
@Override
public void onSubscribe(Disposable d) {
DisposableHelper.replace(this, d);
}
@Override
public void onSuccess(R t) {
parent.innerSuccess(t);
}
@Override
public void onError(Throwable e) {
parent.innerError(e);
}
void dispose() {
DisposableHelper.dispose(this);
}
}
}
}