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rxjava2-backport developed by David Karnok
/**
* Copyright 2015 David Karnok and Netflix, Inc.
*
* 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.rxjava2.internal.operators.nbp;
import java.util.Queue;
import java.util.concurrent.atomic.*;
import hu.akarnokd.rxjava2.NbpObservable;
import hu.akarnokd.rxjava2.NbpObservable.*;
import hu.akarnokd.rxjava2.disposables.Disposable;
import hu.akarnokd.rxjava2.functions.Function;
import hu.akarnokd.rxjava2.internal.disposables.EmptyDisposable;
import hu.akarnokd.rxjava2.internal.queue.SpscLinkedArrayQueue;
import hu.akarnokd.rxjava2.plugins.RxJavaPlugins;
public final class NbpOnSubscribeZip implements NbpOnSubscribe {
final NbpObservable[] sources;
final Iterable> sourcesIterable;
final Function zipper;
final int bufferSize;
final boolean delayError;
public NbpOnSubscribeZip(NbpObservable[] sources,
Iterable> sourcesIterable,
Function zipper,
int bufferSize,
boolean delayError) {
this.sources = sources;
this.sourcesIterable = sourcesIterable;
this.zipper = zipper;
this.bufferSize = bufferSize;
this.delayError = delayError;
}
@Override
@SuppressWarnings("unchecked")
public void accept(NbpSubscriber s) {
NbpObservable[] sources = this.sources;
int count = 0;
if (sources == null) {
sources = new NbpObservable[8];
for (NbpObservable p : sourcesIterable) {
if (count == sources.length) {
NbpObservable[] b = new NbpObservable[count + (count >> 2)];
System.arraycopy(sources, 0, b, 0, count);
sources = b;
}
sources[count++] = p;
}
} else {
count = sources.length;
}
if (count == 0) {
EmptyDisposable.complete(s);
return;
}
ZipCoordinator zc = new ZipCoordinator(s, zipper, count, delayError);
zc.subscribe(sources, bufferSize);
}
static final class ZipCoordinator extends AtomicInteger implements Disposable {
/** */
private static final long serialVersionUID = 2983708048395377667L;
final NbpSubscriber actual;
final Function zipper;
final ZipSubscriber[] subscribers;
final Object[] row;
final boolean delayError;
volatile boolean cancelled;
@SuppressWarnings("unchecked")
public ZipCoordinator(NbpSubscriber actual,
Function zipper,
int count, boolean delayError) {
this.actual = actual;
this.zipper = zipper;
this.subscribers = new ZipSubscriber[count];
this.row = new Object[count];
this.delayError = delayError;
}
public void subscribe(NbpObservable[] sources, int bufferSize) {
ZipSubscriber[] s = subscribers;
int len = s.length;
for (int i = 0; i < len; i++) {
s[i] = new ZipSubscriber(this, bufferSize);
}
// this makes sure the contents of the subscribers array is visible
this.lazySet(0);
actual.onSubscribe(this);
for (int i = 0; i < len; i++) {
if (cancelled) {
return;
}
sources[i].subscribe(s[i]);
}
}
@Override
public void dispose() {
if (!cancelled) {
cancelled = true;
if (getAndIncrement() == 0) {
clear();
}
}
}
void clear() {
for (ZipSubscriber zs : subscribers) {
zs.dispose();
zs.queue.clear();
}
}
public void drain() {
if (getAndIncrement() != 0) {
return;
}
int missing = 1;
final ZipSubscriber[] zs = subscribers;
final NbpSubscriber a = actual;
final Object[] os = row;
final boolean delayError = this.delayError;
for (;;) {
for (;;) {
int i = 0;
int emptyCount = 0;
for (ZipSubscriber z : zs) {
boolean d = z.done;
T v = z.queue.peek();
boolean empty = v == null;
if (checkTerminated(d, empty, a, delayError, z)) {
return;
}
if (empty) {
emptyCount++;
continue;
}
os[i] = v;
i++;
}
if (emptyCount != 0) {
break;
}
// consume the row
for (ZipSubscriber z : zs) {
z.queue.poll();
}
R v;
try {
v = zipper.apply(os.clone());
} catch (Throwable ex) {
clear();
a.onError(ex);
return;
}
if (v == null) {
clear();
a.onError(new NullPointerException("The zipper returned a null value"));
return;
}
a.onNext(v);
}
missing = addAndGet(-missing);
if (missing == 0) {
return;
}
}
}
boolean checkTerminated(boolean d, boolean empty, NbpSubscriber a, boolean delayError, ZipSubscriber source) {
if (cancelled) {
clear();
return true;
}
if (d) {
if (delayError) {
if (empty) {
Throwable e = source.error;
clear();
if (e != null) {
a.onError(e);
} else {
a.onComplete();
}
return true;
}
} else {
Throwable e = source.error;
if (e != null) {
clear();
a.onError(e);
return true;
} else
if (empty) {
clear();
a.onComplete();
return true;
}
}
}
return false;
}
}
static final class ZipSubscriber implements NbpSubscriber, Disposable {
final ZipCoordinator parent;
final Queue queue;
volatile boolean done;
Throwable error;
volatile Disposable s;
@SuppressWarnings("rawtypes")
static final AtomicReferenceFieldUpdater S =
AtomicReferenceFieldUpdater.newUpdater(ZipSubscriber.class, Disposable.class, "s");
static final Disposable CANCELLED = new Disposable() {
@Override
public void dispose() { }
};
public ZipSubscriber(ZipCoordinator parent, int bufferSize) {
this.parent = parent;
this.queue = new SpscLinkedArrayQueue(bufferSize);
}
@Override
public void onSubscribe(Disposable s) {
for (;;) {
Disposable current = this.s;
if (current == CANCELLED) {
s.dispose();
return;
}
if (current != null) {
s.dispose();
RxJavaPlugins.onError(new IllegalStateException("Subscription already set!"));
return;
}
if (S.compareAndSet(this, null, s)) {
return;
} else {
s.dispose();
}
}
}
@Override
public void onNext(T t) {
if (t == null) {
s.dispose();
onError(new NullPointerException());
return;
}
if (!queue.offer(t)) {
s.dispose();
onError(new IllegalStateException("Queue full?!"));
return;
}
parent.drain();
}
@Override
public void onError(Throwable t) {
error = t;
done = true;
parent.drain();
}
@Override
public void onComplete() {
done = true;
parent.drain();
}
@Override
public void dispose() {
Disposable s = this.s;
if (s != CANCELLED) {
s = S.getAndSet(this, CANCELLED);
if (s != CANCELLED && s != null) {
s.dispose();
}
}
}
}
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