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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.flowable;
import java.util.ArrayDeque;
import java.util.concurrent.atomic.*;
import org.reactivestreams.*;
import io.reactivex.*;
import io.reactivex.internal.queue.SpscLinkedArrayQueue;
import io.reactivex.internal.subscriptions.SubscriptionHelper;
import io.reactivex.internal.util.BackpressureHelper;
import io.reactivex.plugins.RxJavaPlugins;
import io.reactivex.processors.UnicastProcessor;
public final class FlowableWindow extends AbstractFlowableWithUpstream> {
final long size;
final long skip;
final int bufferSize;
public FlowableWindow(Flowable source, long size, long skip, int bufferSize) {
super(source);
this.size = size;
this.skip = skip;
this.bufferSize = bufferSize;
}
@Override
public void subscribeActual(Subscriber> s) {
if (skip == size) {
source.subscribe(new WindowExactSubscriber(s, size, bufferSize));
} else
if (skip > size) {
source.subscribe(new WindowSkipSubscriber(s, size, skip, bufferSize));
} else {
source.subscribe(new WindowOverlapSubscriber(s, size, skip, bufferSize));
}
}
static final class WindowExactSubscriber
extends AtomicInteger
implements FlowableSubscriber, Subscription, Runnable {
private static final long serialVersionUID = -2365647875069161133L;
final Subscriber> downstream;
final long size;
final AtomicBoolean once;
final int bufferSize;
long index;
Subscription upstream;
UnicastProcessor window;
WindowExactSubscriber(Subscriber> actual, long size, int bufferSize) {
super(1);
this.downstream = actual;
this.size = size;
this.once = new AtomicBoolean();
this.bufferSize = bufferSize;
}
@Override
public void onSubscribe(Subscription s) {
if (SubscriptionHelper.validate(this.upstream, s)) {
this.upstream = s;
downstream.onSubscribe(this);
}
}
@Override
public void onNext(T t) {
long i = index;
UnicastProcessor w = window;
if (i == 0) {
getAndIncrement();
w = UnicastProcessor.create(bufferSize, this);
window = w;
downstream.onNext(w);
}
i++;
w.onNext(t);
if (i == size) {
index = 0;
window = null;
w.onComplete();
} else {
index = i;
}
}
@Override
public void onError(Throwable t) {
Processor w = window;
if (w != null) {
window = null;
w.onError(t);
}
downstream.onError(t);
}
@Override
public void onComplete() {
Processor w = window;
if (w != null) {
window = null;
w.onComplete();
}
downstream.onComplete();
}
@Override
public void request(long n) {
if (SubscriptionHelper.validate(n)) {
long u = BackpressureHelper.multiplyCap(size, n);
upstream.request(u);
}
}
@Override
public void cancel() {
if (once.compareAndSet(false, true)) {
run();
}
}
@Override
public void run() {
if (decrementAndGet() == 0) {
upstream.cancel();
}
}
}
static final class WindowSkipSubscriber
extends AtomicInteger
implements FlowableSubscriber, Subscription, Runnable {
private static final long serialVersionUID = -8792836352386833856L;
final Subscriber> downstream;
final long size;
final long skip;
final AtomicBoolean once;
final AtomicBoolean firstRequest;
final int bufferSize;
long index;
Subscription upstream;
UnicastProcessor window;
WindowSkipSubscriber(Subscriber> actual, long size, long skip, int bufferSize) {
super(1);
this.downstream = actual;
this.size = size;
this.skip = skip;
this.once = new AtomicBoolean();
this.firstRequest = new AtomicBoolean();
this.bufferSize = bufferSize;
}
@Override
public void onSubscribe(Subscription s) {
if (SubscriptionHelper.validate(this.upstream, s)) {
this.upstream = s;
downstream.onSubscribe(this);
}
}
@Override
public void onNext(T t) {
long i = index;
UnicastProcessor w = window;
if (i == 0) {
getAndIncrement();
w = UnicastProcessor.create(bufferSize, this);
window = w;
downstream.onNext(w);
}
i++;
if (w != null) {
w.onNext(t);
}
if (i == size) {
window = null;
w.onComplete();
}
if (i == skip) {
index = 0;
} else {
index = i;
}
}
@Override
public void onError(Throwable t) {
Processor w = window;
if (w != null) {
window = null;
w.onError(t);
}
downstream.onError(t);
}
@Override
public void onComplete() {
Processor w = window;
if (w != null) {
window = null;
w.onComplete();
}
downstream.onComplete();
}
@Override
public void request(long n) {
if (SubscriptionHelper.validate(n)) {
if (!firstRequest.get() && firstRequest.compareAndSet(false, true)) {
long u = BackpressureHelper.multiplyCap(size, n);
long v = BackpressureHelper.multiplyCap(skip - size, n - 1);
long w = BackpressureHelper.addCap(u, v);
upstream.request(w);
} else {
long u = BackpressureHelper.multiplyCap(skip, n);
upstream.request(u);
}
}
}
@Override
public void cancel() {
if (once.compareAndSet(false, true)) {
run();
}
}
@Override
public void run() {
if (decrementAndGet() == 0) {
upstream.cancel();
}
}
}
static final class WindowOverlapSubscriber
extends AtomicInteger
implements FlowableSubscriber, Subscription, Runnable {
private static final long serialVersionUID = 2428527070996323976L;
final Subscriber> downstream;
final SpscLinkedArrayQueue> queue;
final long size;
final long skip;
final ArrayDeque> windows;
final AtomicBoolean once;
final AtomicBoolean firstRequest;
final AtomicLong requested;
final AtomicInteger wip;
final int bufferSize;
long index;
long produced;
Subscription upstream;
volatile boolean done;
Throwable error;
volatile boolean cancelled;
WindowOverlapSubscriber(Subscriber> actual, long size, long skip, int bufferSize) {
super(1);
this.downstream = actual;
this.size = size;
this.skip = skip;
this.queue = new SpscLinkedArrayQueue>(bufferSize);
this.windows = new ArrayDeque>();
this.once = new AtomicBoolean();
this.firstRequest = new AtomicBoolean();
this.requested = new AtomicLong();
this.wip = new AtomicInteger();
this.bufferSize = bufferSize;
}
@Override
public void onSubscribe(Subscription s) {
if (SubscriptionHelper.validate(this.upstream, s)) {
this.upstream = s;
downstream.onSubscribe(this);
}
}
@Override
public void onNext(T t) {
if (done) {
return;
}
long i = index;
if (i == 0) {
if (!cancelled) {
getAndIncrement();
UnicastProcessor w = UnicastProcessor.create(bufferSize, this);
windows.offer(w);
queue.offer(w);
drain();
}
}
i++;
for (Processor w : windows) {
w.onNext(t);
}
long p = produced + 1;
if (p == size) {
produced = p - skip;
Processor w = windows.poll();
if (w != null) {
w.onComplete();
}
} else {
produced = p;
}
if (i == skip) {
index = 0;
} else {
index = i;
}
}
@Override
public void onError(Throwable t) {
if (done) {
RxJavaPlugins.onError(t);
return;
}
for (Processor w : windows) {
w.onError(t);
}
windows.clear();
error = t;
done = true;
drain();
}
@Override
public void onComplete() {
if (done) {
return;
}
for (Processor w : windows) {
w.onComplete();
}
windows.clear();
done = true;
drain();
}
void drain() {
if (wip.getAndIncrement() != 0) {
return;
}
final Subscriber> a = downstream;
final SpscLinkedArrayQueue> q = queue;
int missed = 1;
for (;;) {
long r = requested.get();
long e = 0;
while (e != r) {
boolean d = done;
UnicastProcessor t = q.poll();
boolean empty = t == null;
if (checkTerminated(d, empty, a, q)) {
return;
}
if (empty) {
break;
}
a.onNext(t);
e++;
}
if (e == r) {
if (checkTerminated(done, q.isEmpty(), a, q)) {
return;
}
}
if (e != 0L && r != Long.MAX_VALUE) {
requested.addAndGet(-e);
}
missed = wip.addAndGet(-missed);
if (missed == 0) {
break;
}
}
}
boolean checkTerminated(boolean d, boolean empty, Subscriber a, SpscLinkedArrayQueue q) {
if (cancelled) {
q.clear();
return true;
}
if (d) {
Throwable e = error;
if (e != null) {
q.clear();
a.onError(e);
return true;
} else
if (empty) {
a.onComplete();
return true;
}
}
return false;
}
@Override
public void request(long n) {
if (SubscriptionHelper.validate(n)) {
BackpressureHelper.add(requested, n);
if (!firstRequest.get() && firstRequest.compareAndSet(false, true)) {
long u = BackpressureHelper.multiplyCap(skip, n - 1);
long v = BackpressureHelper.addCap(size, u);
upstream.request(v);
} else {
long u = BackpressureHelper.multiplyCap(skip, n);
upstream.request(u);
}
drain();
}
}
@Override
public void cancel() {
cancelled = true;
if (once.compareAndSet(false, true)) {
run();
}
}
@Override
public void run() {
if (decrementAndGet() == 0) {
upstream.cancel();
}
}
}
}