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rxjava2-extensions developed by David Karnok
/*
* Copyright 2016-2018 David Karnok
*
* 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.operators;
import java.util.concurrent.atomic.*;
import org.reactivestreams.*;
import io.reactivex.*;
import io.reactivex.exceptions.Exceptions;
import io.reactivex.functions.Function;
import io.reactivex.internal.functions.ObjectHelper;
import io.reactivex.internal.fuseable.*;
import io.reactivex.internal.queue.SpscArrayQueue;
import io.reactivex.internal.subscriptions.SubscriptionHelper;
import io.reactivex.internal.util.*;
import io.reactivex.plugins.RxJavaPlugins;
/**
* FlatMap a bounded number of inner, non-trivial flows (unbound not supported).
*
* @param the input value type
* @param the result value type
*
* @since 0.16.0
*/
final class FlowableFlatMapSync extends Flowable implements FlowableTransformer {
final Publisher source;
final Function> mapper;
final int maxConcurrency;
final int bufferSize;
final boolean depthFirst;
FlowableFlatMapSync(Publisher source, Function> mapper,
int maxConcurrency, int bufferSize, boolean depthFirst) {
this.source = source;
this.mapper = mapper;
this.maxConcurrency = maxConcurrency;
this.bufferSize = bufferSize;
this.depthFirst = depthFirst;
}
@Override
protected void subscribeActual(Subscriber s) {
source.subscribe(new FlatMapOuterSubscriber(s, mapper, maxConcurrency, bufferSize, depthFirst));
}
@Override
public Publisher apply(Flowable upstream) {
return new FlowableFlatMapSync(upstream, mapper, maxConcurrency, bufferSize, depthFirst);
}
interface FlatMapInnerSubscriberSupport {
void innerNext(FlatMapInnerSubscriber inner, R value);
void innerError(FlatMapInnerSubscriber inner, Throwable ex);
void innerComplete(FlatMapInnerSubscriber inner);
void drain();
}
abstract static class BaseFlatMapOuterSubscriber extends AtomicInteger
implements Subscriber, Subscription, FlatMapInnerSubscriberSupport {
private static final long serialVersionUID = -208456984819517117L;
final Subscriber actual;
final Function> mapper;
final int maxConcurrency;
final int bufferSize;
final AtomicLong requested;
final AtomicReferenceArray> subscribers;
final AtomicIntegerArray freelist;
final AtomicThrowable error;
final boolean depthFirst;
final AtomicLong active;
volatile boolean done;
volatile boolean cancelled;
Subscription upstream;
long emitted;
long finished;
static final int PRODUCER_INDEX = 16;
static final int CONSUMER_INDEX = 32;
BaseFlatMapOuterSubscriber(Subscriber actual,
Function> mapper,
int maxConcurrency, int bufferSize,
boolean depthFirst) {
this.actual = actual;
this.mapper = mapper;
this.maxConcurrency = maxConcurrency;
this.bufferSize = bufferSize;
this.requested = new AtomicLong();
this.error = new AtomicThrowable();
this.depthFirst = depthFirst;
this.active = new AtomicLong();
int c = Pow2.roundToPowerOfTwo(maxConcurrency);
this.subscribers = new AtomicReferenceArray>(c);
this.freelist = new AtomicIntegerArray(c + CONSUMER_INDEX + 16);
}
@Override
public final void onSubscribe(Subscription s) {
if (SubscriptionHelper.validate(this.upstream, s)) {
this.upstream = s;
actual.onSubscribe(this);
s.request(maxConcurrency);
}
}
@Override
public final void onNext(T t) {
Publisher p;
try {
p = ObjectHelper.requireNonNull(mapper.apply(t), "The mapper returned a null value");
} catch (Throwable ex) {
Exceptions.throwIfFatal(ex);
upstream.cancel();
cancelInners();
if (error.addThrowable(ex)) {
done = true;
drain();
} else {
RxJavaPlugins.onError(ex);
}
return;
}
if (!cancelled) {
AtomicIntegerArray fl = freelist;
AtomicReferenceArray> s = subscribers;
int m = s.length();
int ci = fl.get(m + CONSUMER_INDEX);
int idx = fl.get(ci);
if (idx == 0) {
idx = ci + 1;
}
FlatMapInnerSubscriber inner = new FlatMapInnerSubscriber(this, bufferSize, idx);
s.lazySet(idx - 1, inner);
fl.lazySet(m + CONSUMER_INDEX, (ci + 1) & (m - 1));
AtomicLong act = active;
act.lazySet(act.get() + 1);
if (cancelled) {
s.lazySet(idx - 1, null);
} else {
p.subscribe(inner);
}
}
}
@Override
public final void onError(Throwable t) {
if (error.addThrowable(t)) {
done = true;
drain();
} else {
RxJavaPlugins.onError(t);
}
}
@Override
public final void onComplete() {
done = true;
drain();
}
@Override
public final void request(long n) {
if (SubscriptionHelper.validate(n)) {
BackpressureHelper.add(requested, n);
drain();
}
}
@Override
public final void cancel() {
if (!cancelled) {
cancelled = true;
upstream.cancel();
cancelInners();
cleanupAfter();
}
}
abstract void cleanupAfter();
final void depthFirst() {
int missed = 1;
long e = emitted;
AtomicReferenceArray> s = subscribers;
int m = s.length();
Subscriber a = actual;
AtomicLong act = active;
for (;;) {
long r = requested.get();
while (e != r) {
if (cancelled) {
return;
}
boolean d = done;
if (d) {
Throwable ex = error.get();
if (ex != null) {
a.onError(error.terminate());
cleanupAfter();
return;
}
}
long n = act.get();
long f = finished;
int innerEmpty = 0;
for (int i = 0, j = 0; i < m && j + f < n; i++) {
FlatMapInnerSubscriber inner = s.get(i);
if (inner != null) {
j++;
boolean innerDone = inner.done;
SimpleQueue q = inner.queue;
if (innerDone && (q == null || q.isEmpty())) {
remove(inner);
finished++;
innerEmpty++;
upstream.request(1);
} else
if (q != null) {
while (e != r) {
if (cancelled) {
return;
}
if (d) {
Throwable ex = error.get();
if (ex != null) {
a.onError(error.terminate());
cleanupAfter();
return;
}
}
R v;
try {
v = q.poll();
} catch (Throwable ex) {
Exceptions.throwIfFatal(ex);
error.addThrowable(ex);
upstream.cancel();
cancelInners();
a.onError(error.terminate());
cleanupAfter();
return;
}
boolean empty = v == null;
if (innerDone && empty) {
remove(inner);
finished++;
innerEmpty++;
upstream.request(1);
break;
}
if (empty) {
innerEmpty++;
break;
}
a.onNext(v);
e++;
inner.producedOne();
}
} else {
innerEmpty++;
}
}
}
n = act.get();
f = finished;
if (d) {
if (n == f) {
a.onComplete();
cleanupAfter();
return;
}
}
if (innerEmpty + f == n) {
break;
}
}
if (e == r) {
if (cancelled) {
return;
}
boolean d = done;
if (d) {
Throwable ex = error.get();
if (ex != null) {
a.onError(error.terminate());
cleanupAfter();
return;
}
long n = act.get();
if (n == finished) {
a.onComplete();
cleanupAfter();
return;
}
}
}
int w = get();
if (w == missed) {
emitted = e;
missed = addAndGet(-missed);
if (missed == 0) {
break;
}
} else {
missed = w;
}
}
}
final void breadthFirst() {
int missed = 1;
long e = emitted;
AtomicReferenceArray> s = subscribers;
int m = s.length();
Subscriber a = actual;
AtomicLong act = active;
for (;;) {
for (;;) {
long r = requested.get();
long alive = act.get() - finished;
int innerEmpty = 0;
int j = 0;
for (int i = 0; i < m && j < alive; i++) {
if (cancelled) {
return;
}
if (done) {
Throwable ex = error.get();
if (ex != null) {
a.onError(error.terminate());
cleanupAfter();
return;
}
}
FlatMapInnerSubscriber inner = s.get(i);
if (inner != null) {
j++;
boolean innerDone = inner.done;
SimpleQueue q = inner.queue;
if (innerDone && (q == null || q.isEmpty())) {
remove(inner);
finished++;
innerEmpty++;
upstream.request(1);
} else
if (q != null) {
if (e != r) {
R v;
try {
v = q.poll();
} catch (Throwable ex) {
Exceptions.throwIfFatal(ex);
error.addThrowable(ex);
upstream.cancel();
cancelInners();
a.onError(error.terminate());
cleanupAfter();
return;
}
if (v == null) {
innerEmpty++;
} else {
a.onNext(v);
e++;
inner.producedOne();
}
}
} else {
innerEmpty++;
}
}
}
if (e == r) {
if (cancelled) {
return;
}
if (done) {
Throwable ex = error.get();
if (ex != null) {
a.onError(error.terminate());
cleanupAfter();
return;
}
if (finished == act.get()) {
a.onComplete();
cleanupAfter();
return;
}
}
break;
}
long f = finished;
long in2 = act.get();
if (done && in2 == f) {
a.onComplete();
cleanupAfter();
return;
}
if (innerEmpty == alive) {
break;
}
}
int w = get();
if (w == missed) {
emitted = e;
missed = addAndGet(-missed);
if (missed == 0) {
break;
}
} else {
missed = w;
}
}
}
final void remove(FlatMapInnerSubscriber inner) {
AtomicIntegerArray fl = freelist;
AtomicReferenceArray> s = subscribers;
int m = s.length();
int idx = inner.index;
int pi = fl.get(m + PRODUCER_INDEX);
s.lazySet(idx - 1, null);
fl.lazySet(pi, idx);
fl.lazySet(m + PRODUCER_INDEX, (pi + 1) & (m - 1));
}
final void cancelInners() {
AtomicReferenceArray> s = subscribers;
int m = s.length();
for (int i = 0; i < m; i++) {
FlatMapInnerSubscriber inner = s.get(i);
if (inner != null) {
s.lazySet(i, null);
inner.cancel();
}
}
}
}
static final class FlatMapOuterSubscriber extends BaseFlatMapOuterSubscriber {
private static final long serialVersionUID = -5109342841608286301L;
FlatMapOuterSubscriber(Subscriber actual,
Function> mapper, int maxConcurrency, int bufferSize,
boolean depthFirst) {
super(actual, mapper, maxConcurrency, bufferSize, depthFirst);
}
@Override
public void drain() {
if (getAndIncrement() == 0) {
drainLoop();
}
}
void drainLoop() {
if (depthFirst) {
depthFirst();
} else {
breadthFirst();
}
}
@Override
void cleanupAfter() {
}
@Override
public void innerNext(FlatMapInnerSubscriber inner, R item) {
if (get() == 0 && compareAndSet(0, 1)) {
long r = requested.get();
long e = emitted;
if (e != r) {
actual.onNext(item);
emitted = e + 1;
inner.producedOne();
} else {
SimpleQueue q = inner.queue();
q.offer(item);
}
if (decrementAndGet() == 0) {
return;
}
} else {
SimpleQueue q = inner.queue();
q.offer(item);
if (getAndIncrement() != 0) {
return;
}
}
drainLoop();
}
@Override
public void innerError(FlatMapInnerSubscriber inner, Throwable ex) {
remove(inner);
if (error.addThrowable(ex)) {
inner.done = true;
done = true;
upstream.cancel();
cancelInners();
drain();
} else {
RxJavaPlugins.onError(ex);
}
}
@Override
public void innerComplete(FlatMapInnerSubscriber inner) {
inner.done = true;
drain();
}
}
static final class FlatMapInnerSubscriber extends AtomicReference
implements Subscriber {
private static final long serialVersionUID = -4991009168975207961L;
final FlatMapInnerSubscriberSupport parent;
final int bufferSize;
final int limit;
final int index;
int produced;
int fusionMode;
volatile boolean done;
volatile SimpleQueue queue;
FlatMapInnerSubscriber(FlatMapInnerSubscriberSupport parent, int bufferSize, int index) {
this.parent = parent;
this.bufferSize = bufferSize;
this.limit = bufferSize - (bufferSize >> 2);
this.index = index;
}
@Override
public void onSubscribe(Subscription s) {
if (SubscriptionHelper.setOnce(this, s)) {
if (s instanceof QueueSubscription) {
@SuppressWarnings("unchecked")
QueueSubscription qs = (QueueSubscription) s;
int m = qs.requestFusion(QueueSubscription.ANY | QueueSubscription.BOUNDARY);
if (m == QueueSubscription.SYNC) {
fusionMode = m;
queue = qs;
done = true;
parent.drain();
return;
}
if (m == QueueSubscription.ASYNC) {
fusionMode = m;
queue = qs;
s.request(bufferSize);
return;
}
}
s.request(bufferSize);
}
}
@Override
public void onNext(R t) {
if (fusionMode == QueueSubscription.NONE) {
parent.innerNext(this, t);
} else {
parent.drain();
}
}
@Override
public void onError(Throwable t) {
parent.innerError(this, t);
}
@Override
public void onComplete() {
parent.innerComplete(this);
}
void cancel() {
SubscriptionHelper.cancel(this);
}
void producedOne() {
if (fusionMode != QueueSubscription.SYNC) {
int p = produced + 1;
if (p == limit) {
produced = 0;
get().request(p);
} else {
produced = p;
}
}
}
SimpleQueue queue() {
SimpleQueue q = queue;
if (q == null) {
q = new SpscArrayQueue(bufferSize);
queue = q;
}
return q;
}
}
}