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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.internal.operators.observable;
import java.util.*;
import java.util.concurrent.Callable;
import java.util.concurrent.atomic.*;
import io.reactivex.ObservableSource;
import io.reactivex.Observer;
import io.reactivex.disposables.Disposable;
import io.reactivex.exceptions.*;
import io.reactivex.functions.Function;
import io.reactivex.internal.disposables.DisposableHelper;
import io.reactivex.internal.functions.ObjectHelper;
import io.reactivex.internal.fuseable.*;
import io.reactivex.internal.queue.*;
import io.reactivex.internal.util.*;
import io.reactivex.plugins.RxJavaPlugins;
public final class ObservableFlatMap extends AbstractObservableWithUpstream {
final Function> mapper;
final boolean delayErrors;
final int maxConcurrency;
final int bufferSize;
public ObservableFlatMap(ObservableSource source,
Function> mapper,
boolean delayErrors, int maxConcurrency, int bufferSize) {
super(source);
this.mapper = mapper;
this.delayErrors = delayErrors;
this.maxConcurrency = maxConcurrency;
this.bufferSize = bufferSize;
}
@Override
public void subscribeActual(Observer t) {
if (ObservableScalarXMap.tryScalarXMapSubscribe(source, t, mapper)) {
return;
}
source.subscribe(new MergeObserver(t, mapper, delayErrors, maxConcurrency, bufferSize));
}
static final class MergeObserver extends AtomicInteger implements Disposable, Observer {
private static final long serialVersionUID = -2117620485640801370L;
final Observer downstream;
final Function> mapper;
final boolean delayErrors;
final int maxConcurrency;
final int bufferSize;
volatile SimplePlainQueue queue;
volatile boolean done;
final AtomicThrowable errors = new AtomicThrowable();
volatile boolean cancelled;
final AtomicReference[]> observers;
static final InnerObserver[] EMPTY = new InnerObserver[0];
static final InnerObserver[] CANCELLED = new InnerObserver[0];
Disposable upstream;
long uniqueId;
long lastId;
int lastIndex;
Queue> sources;
int wip;
MergeObserver(Observer actual, Function> mapper,
boolean delayErrors, int maxConcurrency, int bufferSize) {
this.downstream = actual;
this.mapper = mapper;
this.delayErrors = delayErrors;
this.maxConcurrency = maxConcurrency;
this.bufferSize = bufferSize;
if (maxConcurrency != Integer.MAX_VALUE) {
sources = new ArrayDeque>(maxConcurrency);
}
this.observers = new AtomicReference[]>(EMPTY);
}
@Override
public void onSubscribe(Disposable d) {
if (DisposableHelper.validate(this.upstream, d)) {
this.upstream = d;
downstream.onSubscribe(this);
}
}
@Override
public void onNext(T t) {
// safeguard against misbehaving sources
if (done) {
return;
}
ObservableSource p;
try {
p = ObjectHelper.requireNonNull(mapper.apply(t), "The mapper returned a null ObservableSource");
} catch (Throwable e) {
Exceptions.throwIfFatal(e);
upstream.dispose();
onError(e);
return;
}
if (maxConcurrency != Integer.MAX_VALUE) {
synchronized (this) {
if (wip == maxConcurrency) {
sources.offer(p);
return;
}
wip++;
}
}
subscribeInner(p);
}
@SuppressWarnings("unchecked")
void subscribeInner(ObservableSource p) {
for (;;) {
if (p instanceof Callable) {
if (tryEmitScalar(((Callable)p)) && maxConcurrency != Integer.MAX_VALUE) {
boolean empty = false;
synchronized (this) {
p = sources.poll();
if (p == null) {
wip--;
empty = true;
}
}
if (empty) {
drain();
break;
}
} else {
break;
}
} else {
InnerObserver inner = new InnerObserver(this, uniqueId++);
if (addInner(inner)) {
p.subscribe(inner);
}
break;
}
}
}
boolean addInner(InnerObserver inner) {
for (;;) {
InnerObserver[] a = observers.get();
if (a == CANCELLED) {
inner.dispose();
return false;
}
int n = a.length;
InnerObserver[] b = new InnerObserver[n + 1];
System.arraycopy(a, 0, b, 0, n);
b[n] = inner;
if (observers.compareAndSet(a, b)) {
return true;
}
}
}
void removeInner(InnerObserver inner) {
for (;;) {
InnerObserver[] a = observers.get();
int n = a.length;
if (n == 0) {
return;
}
int j = -1;
for (int i = 0; i < n; i++) {
if (a[i] == inner) {
j = i;
break;
}
}
if (j < 0) {
return;
}
InnerObserver[] b;
if (n == 1) {
b = EMPTY;
} else {
b = new InnerObserver[n - 1];
System.arraycopy(a, 0, b, 0, j);
System.arraycopy(a, j + 1, b, j, n - j - 1);
}
if (observers.compareAndSet(a, b)) {
return;
}
}
}
boolean tryEmitScalar(Callable value) {
U u;
try {
u = value.call();
} catch (Throwable ex) {
Exceptions.throwIfFatal(ex);
errors.addThrowable(ex);
drain();
return true;
}
if (u == null) {
return true;
}
if (get() == 0 && compareAndSet(0, 1)) {
downstream.onNext(u);
if (decrementAndGet() == 0) {
return true;
}
} else {
SimplePlainQueue q = queue;
if (q == null) {
if (maxConcurrency == Integer.MAX_VALUE) {
q = new SpscLinkedArrayQueue(bufferSize);
} else {
q = new SpscArrayQueue(maxConcurrency);
}
queue = q;
}
if (!q.offer(u)) {
onError(new IllegalStateException("Scalar queue full?!"));
return true;
}
if (getAndIncrement() != 0) {
return false;
}
}
drainLoop();
return true;
}
void tryEmit(U value, InnerObserver inner) {
if (get() == 0 && compareAndSet(0, 1)) {
downstream.onNext(value);
if (decrementAndGet() == 0) {
return;
}
} else {
SimpleQueue q = inner.queue;
if (q == null) {
q = new SpscLinkedArrayQueue(bufferSize);
inner.queue = q;
}
q.offer(value);
if (getAndIncrement() != 0) {
return;
}
}
drainLoop();
}
@Override
public void onError(Throwable t) {
if (done) {
RxJavaPlugins.onError(t);
return;
}
if (errors.addThrowable(t)) {
done = true;
drain();
} else {
RxJavaPlugins.onError(t);
}
}
@Override
public void onComplete() {
if (done) {
return;
}
done = true;
drain();
}
@Override
public void dispose() {
if (!cancelled) {
cancelled = true;
if (disposeAll()) {
Throwable ex = errors.terminate();
if (ex != null && ex != ExceptionHelper.TERMINATED) {
RxJavaPlugins.onError(ex);
}
}
}
}
@Override
public boolean isDisposed() {
return cancelled;
}
void drain() {
if (getAndIncrement() == 0) {
drainLoop();
}
}
void drainLoop() {
final Observer child = this.downstream;
int missed = 1;
for (;;) {
if (checkTerminate()) {
return;
}
SimplePlainQueue svq = queue;
if (svq != null) {
for (;;) {
if (checkTerminate()) {
return;
}
U o = svq.poll();
if (o == null) {
break;
}
child.onNext(o);
}
}
boolean d = done;
svq = queue;
InnerObserver[] inner = observers.get();
int n = inner.length;
int nSources = 0;
if (maxConcurrency != Integer.MAX_VALUE) {
synchronized (this) {
nSources = sources.size();
}
}
if (d && (svq == null || svq.isEmpty()) && n == 0 && nSources == 0) {
Throwable ex = errors.terminate();
if (ex != ExceptionHelper.TERMINATED) {
if (ex == null) {
child.onComplete();
} else {
child.onError(ex);
}
}
return;
}
int innerCompleted = 0;
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")
InnerObserver is = (InnerObserver)inner[j];
SimpleQueue q = is.queue;
if (q != null) {
for (;;) {
U o;
try {
o = q.poll();
} catch (Throwable ex) {
Exceptions.throwIfFatal(ex);
is.dispose();
errors.addThrowable(ex);
if (checkTerminate()) {
return;
}
removeInner(is);
innerCompleted++;
j++;
if (j == n) {
j = 0;
}
continue sourceLoop;
}
if (o == null) {
break;
}
child.onNext(o);
if (checkTerminate()) {
return;
}
}
}
boolean innerDone = is.done;
SimpleQueue innerQueue = is.queue;
if (innerDone && (innerQueue == null || innerQueue.isEmpty())) {
removeInner(is);
if (checkTerminate()) {
return;
}
innerCompleted++;
}
j++;
if (j == n) {
j = 0;
}
}
lastIndex = j;
lastId = inner[j].id;
}
if (innerCompleted != 0) {
if (maxConcurrency != Integer.MAX_VALUE) {
while (innerCompleted-- != 0) {
ObservableSource p;
synchronized (this) {
p = sources.poll();
if (p == null) {
wip--;
continue;
}
}
subscribeInner(p);
}
}
continue;
}
missed = addAndGet(-missed);
if (missed == 0) {
break;
}
}
}
boolean checkTerminate() {
if (cancelled) {
return true;
}
Throwable e = errors.get();
if (!delayErrors && (e != null)) {
disposeAll();
e = errors.terminate();
if (e != ExceptionHelper.TERMINATED) {
downstream.onError(e);
}
return true;
}
return false;
}
boolean disposeAll() {
upstream.dispose();
InnerObserver[] a = observers.get();
if (a != CANCELLED) {
a = observers.getAndSet(CANCELLED);
if (a != CANCELLED) {
for (InnerObserver inner : a) {
inner.dispose();
}
return true;
}
}
return false;
}
}
static final class InnerObserver extends AtomicReference
implements Observer {
private static final long serialVersionUID = -4606175640614850599L;
final long id;
final MergeObserver parent;
volatile boolean done;
volatile SimpleQueue queue;
int fusionMode;
InnerObserver(MergeObserver parent, long id) {
this.id = id;
this.parent = parent;
}
@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) {
fusionMode = m;
queue = qd;
done = true;
parent.drain();
return;
}
if (m == QueueDisposable.ASYNC) {
fusionMode = m;
queue = qd;
}
}
}
}
@Override
public void onNext(U t) {
if (fusionMode == QueueDisposable.NONE) {
parent.tryEmit(t, this);
} else {
parent.drain();
}
}
@Override
public void onError(Throwable t) {
if (parent.errors.addThrowable(t)) {
if (!parent.delayErrors) {
parent.disposeAll();
}
done = true;
parent.drain();
} else {
RxJavaPlugins.onError(t);
}
}
@Override
public void onComplete() {
done = true;
parent.drain();
}
public void dispose() {
DisposableHelper.dispose(this);
}
}
}
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