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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;
import java.util.Queue;
import java.util.concurrent.atomic.*;
import org.reactivestreams.*;
import hu.akarnokd.rxjava2.functions.Function;
import hu.akarnokd.rxjava2.internal.queue.*;
import hu.akarnokd.rxjava2.internal.subscriptions.EmptySubscription;
import hu.akarnokd.rxjava2.internal.util.*;
import hu.akarnokd.rxjava2.plugins.RxJavaPlugins;
public final class PublisherZip implements Publisher {
final Publisher[] sources;
final Iterable> sourcesIterable;
final Function zipper;
final int bufferSize;
final boolean delayError;
public PublisherZip(Publisher[] 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 subscribe(Subscriber s) {
Publisher[] sources = this.sources;
int count = 0;
if (sources == null) {
sources = new Publisher[8];
for (Publisher p : sourcesIterable) {
if (count == sources.length) {
Publisher[] b = new Publisher[count + (count >> 2)];
System.arraycopy(sources, 0, b, 0, count);
sources = b;
}
sources[count++] = p;
}
} else {
count = sources.length;
}
if (count == 0) {
EmptySubscription.complete(s);
return;
}
ZipCoordinator zc = new ZipCoordinator(s, zipper, count, delayError);
zc.subscribe(sources, bufferSize);
}
static final class ZipCoordinator extends AtomicInteger implements Subscription {
/** */
private static final long serialVersionUID = 2983708048395377667L;
final Subscriber actual;
final Function zipper;
final ZipSubscriber[] subscribers;
final Object[] row;
final boolean delayError;
volatile long requested;
@SuppressWarnings("rawtypes")
static final AtomicLongFieldUpdater REQUESTED =
AtomicLongFieldUpdater.newUpdater(ZipCoordinator.class, "requested");
volatile boolean cancelled;
@SuppressWarnings("unchecked")
public ZipCoordinator(Subscriber 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(Publisher[] 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
REQUESTED.lazySet(this, 0);
actual.onSubscribe(this);
for (int i = 0; i < len; i++) {
if (cancelled) {
return;
}
sources[i].subscribe(s[i]);
}
}
@Override
public void request(long n) {
if (n <= 0) {
RxJavaPlugins.onError(new IllegalArgumentException("n > required but it was " + n));
return;
}
BackpressureHelper.add(REQUESTED, this, n);
drain();
}
@Override
public void cancel() {
if (!cancelled) {
cancelled = true;
if (getAndIncrement() == 0) {
clear();
}
}
}
void clear() {
for (ZipSubscriber zs : subscribers) {
zs.cancel();
zs.queue.clear();
}
}
public void drain() {
if (getAndIncrement() != 0) {
return;
}
int missing = 1;
final ZipSubscriber[] zs = subscribers;
final Subscriber a = actual;
final Object[] os = row;
final boolean delayError = this.delayError;
for (;;) {
long r = requested;
boolean unbounded = r == Long.MAX_VALUE;
long e = 0;
while (r != 0) {
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 null"));
return;
}
a.onNext(v);
r--;
e++;
}
if (e != 0) {
if (!unbounded) {
REQUESTED.addAndGet(this, -e);
}
for (ZipSubscriber z : zs) {
z.request(e);
}
}
missing = addAndGet(-missing);
if (missing == 0) {
return;
}
}
}
boolean checkTerminated(boolean d, boolean empty, Subscriber 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 extends AtomicLong implements Subscriber, Subscription {
/** */
private static final long serialVersionUID = -4627193790118206028L;
final ZipCoordinator parent;
final int bufferSize;
final Queue queue;
volatile boolean done;
Throwable error;
volatile Subscription s;
@SuppressWarnings("rawtypes")
static final AtomicReferenceFieldUpdater S =
AtomicReferenceFieldUpdater.newUpdater(ZipSubscriber.class, Subscription.class, "s");
Subscription cachedS;
static final Subscription CANCELLED = new Subscription() {
@Override
public void request(long n) {
}
@Override
public void cancel() {
}
};
public ZipSubscriber(ZipCoordinator parent, int bufferSize) {
this.parent = parent;
this.bufferSize = bufferSize;
Queue q;
if (Pow2.isPowerOfTwo(bufferSize)) {
q = new SpscArrayQueue(bufferSize);
} else {
q = new SpscExactArrayQueue(bufferSize);
}
this.queue = q;
}
@Override
public void onSubscribe(Subscription s) {
for (;;) {
Subscription current = this.s;
if (current == CANCELLED) {
s.cancel();
return;
}
if (current != null) {
s.cancel();
RxJavaPlugins.onError(new IllegalStateException("Subscription already set!"));
return;
}
if (S.compareAndSet(this, null, s)) {
lazySet(bufferSize);
s.request(bufferSize);
return;
} else {
s.cancel();
}
}
}
@Override
public void onNext(T t) {
if (t == null) {
s.cancel();
onError(new NullPointerException());
return;
}
if (!queue.offer(t)) {
s.cancel();
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 request(long n) {
lazySet(BackpressureHelper.addCap(get(), n));
// this method is only called if s is no longer null;
if (cachedS == null) {
cachedS = s;
}
cachedS.request(n);
}
@Override
public void cancel() {
Subscription s = this.s;
if (s != CANCELLED) {
s = S.getAndSet(this, CANCELLED);
if (s != CANCELLED && s != null) {
s.cancel();
}
}
}
public void produced(long n) {
long v = get() - n;
if (v < 0L) {
RxJavaPlugins.onError(new IllegalArgumentException("More produced than requested: " + v));
v = 0;
}
lazySet(v);
}
}
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