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rxjava3-flowable developed by David Karnok
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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.flowable.internal.operators;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.atomic.*;
import org.reactivestreams.*;
import hu.akarnokd.reactivestreams.extensions.RelaxedSubscriber;
import io.reactivex.common.RxJavaCommonPlugins;
import io.reactivex.common.annotations.Nullable;
import io.reactivex.common.exceptions.Exceptions;
import io.reactivex.common.functions.Function;
import io.reactivex.common.internal.functions.ObjectHelper;
import io.reactivex.flowable.*;
import io.reactivex.flowable.internal.queues.SpscLinkedArrayQueue;
import io.reactivex.flowable.internal.subscriptions.*;
import io.reactivex.flowable.internal.utils.BackpressureHelper;
public final class FlowableGroupBy extends AbstractFlowableWithUpstream> {
final Function keySelector;
final Function valueSelector;
final int bufferSize;
final boolean delayError;
public FlowableGroupBy(Flowable source, Function keySelector, Function valueSelector, int bufferSize, boolean delayError) {
super(source);
this.keySelector = keySelector;
this.valueSelector = valueSelector;
this.bufferSize = bufferSize;
this.delayError = delayError;
}
@Override
protected void subscribeActual(Subscriber> s) {
source.subscribe(new GroupBySubscriber(s, keySelector, valueSelector, bufferSize, delayError));
}
public static final class GroupBySubscriber
extends BasicIntFusedQueueSubscription>
implements RelaxedSubscriber {
private static final long serialVersionUID = -3688291656102519502L;
final Subscriber> actual;
final Function keySelector;
final Function valueSelector;
final int bufferSize;
final boolean delayError;
final Map> groups;
final SpscLinkedArrayQueue> queue;
static final Object NULL_KEY = new Object();
Subscription s;
final AtomicBoolean cancelled = new AtomicBoolean();
final AtomicLong requested = new AtomicLong();
final AtomicInteger groupCount = new AtomicInteger(1);
Throwable error;
volatile boolean done;
boolean outputFused;
public GroupBySubscriber(Subscriber> actual, Function keySelector, Function valueSelector, int bufferSize, boolean delayError) {
this.actual = actual;
this.keySelector = keySelector;
this.valueSelector = valueSelector;
this.bufferSize = bufferSize;
this.delayError = delayError;
this.groups = new ConcurrentHashMap>();
this.queue = new SpscLinkedArrayQueue>(bufferSize);
}
@Override
public void onSubscribe(Subscription s) {
if (SubscriptionHelper.validate(this.s, s)) {
this.s = s;
actual.onSubscribe(this);
s.request(bufferSize);
}
}
@Override
public void onNext(T t) {
if (done) {
return;
}
final SpscLinkedArrayQueue> q = this.queue;
K key;
try {
key = keySelector.apply(t);
} catch (Throwable ex) {
Exceptions.throwIfFatal(ex);
s.cancel();
onError(ex);
return;
}
boolean newGroup = false;
Object mapKey = key != null ? key : NULL_KEY;
GroupedUnicast group = groups.get(mapKey);
if (group == null) {
// if the main has been cancelled, stop creating groups
// and skip this value
if (cancelled.get()) {
return;
}
group = GroupedUnicast.createWith(key, bufferSize, this, delayError);
groups.put(mapKey, group);
groupCount.getAndIncrement();
newGroup = true;
}
V v;
try {
v = ObjectHelper.requireNonNull(valueSelector.apply(t), "The valueSelector returned null");
} catch (Throwable ex) {
Exceptions.throwIfFatal(ex);
s.cancel();
onError(ex);
return;
}
group.onNext(v);
if (newGroup) {
q.offer(group);
drain();
}
}
@Override
public void onError(Throwable t) {
if (done) {
RxJavaCommonPlugins.onError(t);
return;
}
for (GroupedUnicast g : groups.values()) {
g.onError(t);
}
groups.clear();
error = t;
done = true;
drain();
}
@Override
public void onComplete() {
if (!done) {
for (GroupedUnicast g : groups.values()) {
g.onComplete();
}
groups.clear();
done = true;
drain();
}
}
@Override
public void request(long n) {
if (SubscriptionHelper.validate(n)) {
BackpressureHelper.add(requested, n);
drain();
}
}
@Override
public void cancel() {
// cancelling the main source means we don't want any more groups
// but running groups still require new values
if (cancelled.compareAndSet(false, true)) {
if (groupCount.decrementAndGet() == 0) {
s.cancel();
}
}
}
public void cancel(K key) {
Object mapKey = key != null ? key : NULL_KEY;
groups.remove(mapKey);
if (groupCount.decrementAndGet() == 0) {
s.cancel();
if (getAndIncrement() == 0) {
queue.clear();
}
}
}
void drain() {
if (getAndIncrement() != 0) {
return;
}
if (outputFused) {
drainFused();
} else {
drainNormal();
}
}
void drainFused() {
int missed = 1;
final SpscLinkedArrayQueue> q = this.queue;
final Subscriber> a = this.actual;
for (;;) {
if (cancelled.get()) {
q.clear();
return;
}
boolean d = done;
if (d && !delayError) {
Throwable ex = error;
if (ex != null) {
q.clear();
a.onError(ex);
return;
}
}
a.onNext(null);
if (d) {
Throwable ex = error;
if (ex != null) {
a.onError(ex);
} else {
a.onComplete();
}
return;
}
missed = addAndGet(-missed);
if (missed == 0) {
return;
}
}
}
void drainNormal() {
int missed = 1;
final SpscLinkedArrayQueue> q = this.queue;
final Subscriber> a = this.actual;
for (;;) {
long r = requested.get();
long e = 0L;
while (e != r) {
boolean d = done;
GroupedFlowable t = q.poll();
boolean empty = t == null;
if (checkTerminated(d, empty, a, q)) {
return;
}
if (empty) {
break;
}
a.onNext(t);
e++;
}
if (e == r && checkTerminated(done, q.isEmpty(), a, q)) {
return;
}
if (e != 0L) {
if (r != Long.MAX_VALUE) {
requested.addAndGet(-e);
}
s.request(e);
}
missed = addAndGet(-missed);
if (missed == 0) {
break;
}
}
}
boolean checkTerminated(boolean d, boolean empty, Subscriber a, SpscLinkedArrayQueue q) {
if (cancelled.get()) {
q.clear();
return true;
}
if (delayError) {
if (d && empty) {
Throwable ex = error;
if (ex != null) {
a.onError(ex);
} else {
a.onComplete();
}
return true;
}
} else {
if (d) {
Throwable ex = error;
if (ex != null) {
q.clear();
a.onError(ex);
return true;
} else if (empty) {
a.onComplete();
return true;
}
}
}
return false;
}
@Override
public int requestFusion(int mode) {
if ((mode & ASYNC) != 0) {
outputFused = true;
return ASYNC;
}
return NONE;
}
@Nullable
@Override
public GroupedFlowable poll() {
return queue.poll();
}
@Override
public void clear() {
queue.clear();
}
@Override
public boolean isEmpty() {
return queue.isEmpty();
}
}
static final class GroupedUnicast extends GroupedFlowable {
final State state;
public static GroupedUnicast createWith(K key, int bufferSize, GroupBySubscriber parent, boolean delayError) {
State state = new State(bufferSize, parent, key, delayError);
return new GroupedUnicast(key, state);
}
protected GroupedUnicast(K key, State state) {
super(key);
this.state = state;
}
@Override
protected void subscribeActual(Subscriber s) {
state.subscribe(s);
}
public void onNext(T t) {
state.onNext(t);
}
public void onError(Throwable e) {
state.onError(e);
}
public void onComplete() {
state.onComplete();
}
}
static final class State extends BasicIntFusedQueueSubscription implements Publisher {
private static final long serialVersionUID = -3852313036005250360L;
final K key;
final SpscLinkedArrayQueue queue;
final GroupBySubscriber parent;
final boolean delayError;
final AtomicLong requested = new AtomicLong();
volatile boolean done;
Throwable error;
final AtomicBoolean cancelled = new AtomicBoolean();
final AtomicReference> actual = new AtomicReference>();
final AtomicBoolean once = new AtomicBoolean();
boolean outputFused;
int produced;
State(int bufferSize, GroupBySubscriber parent, K key, boolean delayError) {
this.queue = new SpscLinkedArrayQueue(bufferSize);
this.parent = parent;
this.key = key;
this.delayError = delayError;
}
@Override
public void request(long n) {
if (SubscriptionHelper.validate(n)) {
BackpressureHelper.add(requested, n);
drain();
}
}
@Override
public void cancel() {
if (cancelled.compareAndSet(false, true)) {
parent.cancel(key);
}
}
@Override
public void subscribe(Subscriber s) {
if (once.compareAndSet(false, true)) {
s.onSubscribe(this);
actual.lazySet(s);
drain();
} else {
EmptySubscription.error(new IllegalStateException("Only one Subscriber allowed!"), s);
}
}
public void onNext(T t) {
queue.offer(t);
drain();
}
public void onError(Throwable e) {
error = e;
done = true;
drain();
}
public void onComplete() {
done = true;
drain();
}
void drain() {
if (getAndIncrement() != 0) {
return;
}
if (outputFused) {
drainFused();
} else {
drainNormal();
}
}
void drainFused() {
int missed = 1;
final SpscLinkedArrayQueue q = this.queue;
Subscriber a = this.actual.get();
for (;;) {
if (a != null) {
if (cancelled.get()) {
q.clear();
return;
}
boolean d = done;
if (d && !delayError) {
Throwable ex = error;
if (ex != null) {
q.clear();
a.onError(ex);
return;
}
}
a.onNext(null);
if (d) {
Throwable ex = error;
if (ex != null) {
a.onError(ex);
} else {
a.onComplete();
}
return;
}
}
missed = addAndGet(-missed);
if (missed == 0) {
return;
}
if (a == null) {
a = this.actual.get();
}
}
}
void drainNormal() {
int missed = 1;
final SpscLinkedArrayQueue q = queue;
final boolean delayError = this.delayError;
Subscriber a = actual.get();
for (;;) {
if (a != null) {
long r = requested.get();
long e = 0;
while (e != r) {
boolean d = done;
T v = q.poll();
boolean empty = v == null;
if (checkTerminated(d, empty, a, delayError)) {
return;
}
if (empty) {
break;
}
a.onNext(v);
e++;
}
if (e == r && checkTerminated(done, q.isEmpty(), a, delayError)) {
return;
}
if (e != 0L) {
if (r != Long.MAX_VALUE) {
requested.addAndGet(-e);
}
parent.s.request(e);
}
}
missed = addAndGet(-missed);
if (missed == 0) {
break;
}
if (a == null) {
a = actual.get();
}
}
}
boolean checkTerminated(boolean d, boolean empty, Subscriber a, boolean delayError) {
if (cancelled.get()) {
queue.clear();
return true;
}
if (d) {
if (delayError) {
if (empty) {
Throwable e = error;
if (e != null) {
a.onError(e);
} else {
a.onComplete();
}
return true;
}
} else {
Throwable e = error;
if (e != null) {
queue.clear();
a.onError(e);
return true;
} else
if (empty) {
a.onComplete();
return true;
}
}
}
return false;
}
@Override
public int requestFusion(int mode) {
if ((mode & ASYNC) != 0) {
outputFused = true;
return ASYNC;
}
return NONE;
}
@Nullable
@Override
public T poll() {
T v = queue.poll();
if (v != null) {
produced++;
return v;
}
int p = produced;
if (p != 0) {
produced = 0;
parent.s.request(p);
}
return null;
}
@Override
public boolean isEmpty() {
return queue.isEmpty();
}
@Override
public void clear() {
queue.clear();
}
}
}