hu.akarnokd.rxjava2.internal.operators.OperatorFlatMap Maven / Gradle / Ivy
/**
* 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.*;
import java.util.concurrent.atomic.*;
import org.reactivestreams.*;
import hu.akarnokd.rxjava2.Observable.Operator;
import hu.akarnokd.rxjava2.disposables.Disposable;
import hu.akarnokd.rxjava2.exceptions.*;
import hu.akarnokd.rxjava2.functions.Function;
import hu.akarnokd.rxjava2.internal.queue.*;
import hu.akarnokd.rxjava2.internal.subscriptions.SubscriptionHelper;
import hu.akarnokd.rxjava2.internal.util.*;
public final class OperatorFlatMap implements Operator {
final Function> mapper;
final boolean delayErrors;
final int maxConcurrency;
final int bufferSize;
public OperatorFlatMap(
Function> mapper,
boolean delayErrors, int maxConcurrency, int bufferSize) {
this.mapper = mapper;
this.delayErrors = delayErrors;
this.maxConcurrency = maxConcurrency;
this.bufferSize = bufferSize;
}
@Override
public Subscriber apply(Subscriber t) {
return new MergeSubscriber(t, mapper, delayErrors, maxConcurrency, bufferSize);
}
static final class MergeSubscriber extends AtomicInteger implements Subscription, Subscriber {
/** */
private static final long serialVersionUID = -2117620485640801370L;
final Subscriber actual;
final Function> mapper;
final boolean delayErrors;
final int maxConcurrency;
final int bufferSize;
volatile Queue queue;
volatile boolean done;
volatile Queue errors;
@SuppressWarnings("rawtypes")
static final AtomicReferenceFieldUpdater ERRORS =
AtomicReferenceFieldUpdater.newUpdater(MergeSubscriber.class, Queue.class, "errors");
static final Queue ERRORS_CLOSED = new RejectingQueue();
volatile boolean cancelled;
volatile InnerSubscriber[] subscribers;
@SuppressWarnings("rawtypes")
static final AtomicReferenceFieldUpdater SUBSCRIBERS =
AtomicReferenceFieldUpdater.newUpdater(MergeSubscriber.class, InnerSubscriber[].class, "subscribers");
static final InnerSubscriber[] EMPTY = new InnerSubscriber[0];
static final InnerSubscriber[] CANCELLED = new InnerSubscriber[0];
volatile long requested;
@SuppressWarnings("rawtypes")
static final AtomicLongFieldUpdater REQUESTED =
AtomicLongFieldUpdater.newUpdater(MergeSubscriber.class, "requested");
Subscription s;
long uniqueId;
long lastId;
int lastIndex;
int scalarEmitted;
final int scalarLimit;
public MergeSubscriber(Subscriber actual, Function> mapper,
boolean delayErrors, int maxConcurrency, int bufferSize) {
this.actual = actual;
this.mapper = mapper;
this.delayErrors = delayErrors;
this.maxConcurrency = maxConcurrency;
this.bufferSize = bufferSize;
this.scalarLimit = Math.max(1, maxConcurrency >> 1);
SUBSCRIBERS.lazySet(this, EMPTY);
}
@Override
public void onSubscribe(Subscription s) {
if (SubscriptionHelper.validateSubscription(this.s, s)) {
return;
}
this.s = s;
actual.onSubscribe(this);
if (!cancelled) {
if (maxConcurrency == Integer.MAX_VALUE) {
s.request(Long.MAX_VALUE);
} else {
s.request(maxConcurrency);
}
}
}
@Override
public void onNext(T t) {
// safeguard against misbehaving sources
if (done) {
return;
}
Publisher p;
try {
p = mapper.apply(t);
} catch (Throwable e) {
onError(e);
return;
}
if (p instanceof ObservableScalarSource) {
tryEmitScalar(((ObservableScalarSource)p).value());
} else {
InnerSubscriber inner = new InnerSubscriber(this, uniqueId++);
addInner(inner);
p.subscribe(inner);
}
}
void addInner(InnerSubscriber inner) {
for (;;) {
InnerSubscriber[] a = subscribers;
if (a == CANCELLED) {
inner.dispose();
return;
}
int n = a.length;
InnerSubscriber[] b = new InnerSubscriber[n + 1];
System.arraycopy(a, 0, b, 0, n);
b[n] = inner;
if (SUBSCRIBERS.compareAndSet(this, a, b)) {
return;
}
}
}
void removeInner(InnerSubscriber inner) {
for (;;) {
InnerSubscriber[] a = subscribers;
if (a == CANCELLED || a == EMPTY) {
return;
}
int n = a.length;
int j = -1;
for (int i = 0; i < n; i++) {
if (a[i] == inner) {
j = i;
break;
}
}
if (j < 0) {
return;
}
InnerSubscriber[] b;
if (n == 1) {
b = EMPTY;
} else {
b = new InnerSubscriber[n - 1];
System.arraycopy(a, 0, b, 0, j);
System.arraycopy(a, j + 1, b, j, n - j - 1);
}
if (SUBSCRIBERS.compareAndSet(this, a, b)) {
return;
}
}
}
Queue getMainQueue() {
Queue q = queue;
if (q == null) {
if (maxConcurrency == Integer.MAX_VALUE) {
q = new SpscLinkedArrayQueue(bufferSize);
} else {
if (Pow2.isPowerOfTwo(maxConcurrency)) {
q = new SpscArrayQueue(maxConcurrency);
} else {
q = new SpscExactArrayQueue(maxConcurrency);
}
}
queue = q;
}
return q;
}
void tryEmitScalar(U value) {
if (get() == 0 && compareAndSet(0, 1)) {
long r = requested;
if (r != 0L) {
actual.onNext(value);
if (r != Long.MAX_VALUE) {
REQUESTED.decrementAndGet(this);
}
if (maxConcurrency != Integer.MAX_VALUE && !cancelled
&& ++scalarEmitted == scalarLimit) {
scalarEmitted = 0;
s.request(scalarLimit);
}
} else {
Queue q = getMainQueue();
if (!q.offer(value)) {
onError(new IllegalStateException("Scalar queue full?!"));
return;
}
}
if (decrementAndGet() == 0) {
return;
}
} else {
Queue q = getMainQueue();
if (!q.offer(value)) {
onError(new IllegalStateException("Scalar queue full?!"));
return;
}
if (getAndIncrement() != 0) {
return;
}
}
drainLoop();
}
Queue getInnerQueue(InnerSubscriber inner) {
Queue q = inner.queue;
if (q == null) {
q = new SpscArrayQueue(bufferSize);
inner.queue = q;
}
return q;
}
void tryEmit(U value, InnerSubscriber inner) {
if (get() == 0 && compareAndSet(0, 1)) {
long r = requested;
if (r != 0L) {
actual.onNext(value);
if (r != Long.MAX_VALUE) {
REQUESTED.decrementAndGet(this);
}
inner.requestMore(1);
} else {
Queue q = getInnerQueue(inner);
if (!q.offer(value)) {
onError(new MissingBackpressureException("Inner queue full?!"));
return;
}
}
if (decrementAndGet() == 0) {
return;
}
} else {
Queue q = inner.queue;
if (q == null) {
q = new SpscArrayQueue(bufferSize);
inner.queue = q;
}
if (!q.offer(value)) {
onError(new MissingBackpressureException("Inner queue full?!"));
return;
}
if (getAndIncrement() != 0) {
return;
}
}
drainLoop();
}
@Override
public void onError(Throwable t) {
// safeguard against misbehaving sources
if (done) {
return;
}
getErrorQueue().offer(t);
done = true;
drain();
}
@Override
public void onComplete() {
// safeguard against misbehaving sources
if (done) {
return;
}
done = true;
drain();
}
@Override
public void request(long n) {
if (SubscriptionHelper.validateRequest(n)) {
return;
}
BackpressureHelper.add(REQUESTED, this, n);
drain();
}
@Override
public void cancel() {
if (!cancelled) {
cancelled = true;
if (getAndIncrement() == 0) {
s.cancel();
unsubscribe();
}
}
}
void drain() {
if (getAndIncrement() == 0) {
drainLoop();
}
}
void drainLoop() {
final Subscriber child = this.actual;
int missed = 1;
for (;;) {
if (checkTerminate()) {
return;
}
Queue svq = queue;
long r = requested;
boolean unbounded = r == Long.MAX_VALUE;
long replenishMain = 0;
if (svq != null) {
for (;;) {
long scalarEmission = 0;
U o = null;
while (r != 0L) {
o = svq.poll();
if (checkTerminate()) {
return;
}
if (o == null) {
break;
}
child.onNext(o);
replenishMain++;
scalarEmission++;
r--;
}
if (scalarEmission != 0L) {
if (unbounded) {
r = Long.MAX_VALUE;
} else {
r = REQUESTED.addAndGet(this, -scalarEmission);
}
}
if (r == 0L || o == null) {
break;
}
}
}
boolean d = done;
svq = queue;
InnerSubscriber[] inner = subscribers;
int n = inner.length;
if (d && (svq == null || svq.isEmpty()) && n == 0) {
Queue e = errors;
if (e == null || e.isEmpty()) {
child.onComplete();
} else {
reportError(e);
}
return;
}
boolean innerCompleted = false;
if (n != 0) {
long startId = lastId;
int index = lastIndex;
if (n <= index || inner[index].id != startId) {
if (n <= index) {
index = 0;
}
int j = index;
for (int i = 0; i < n; i++) {
if (inner[j].id == startId) {
break;
}
j++;
if (j == n) {
j = 0;
}
}
index = j;
lastIndex = j;
lastId = inner[j].id;
}
int j = index;
for (int i = 0; i < n; i++) {
if (checkTerminate()) {
return;
}
@SuppressWarnings("unchecked")
InnerSubscriber is = (InnerSubscriber)inner[j];
U o = null;
for (;;) {
long produced = 0;
while (r != 0L) {
if (checkTerminate()) {
return;
}
Queue q = is.queue;
if (q == null) {
break;
}
o = q.poll();
if (o == null) {
break;
}
child.onNext(o);
r--;
produced++;
}
if (produced != 0L) {
if (!unbounded) {
r = REQUESTED.addAndGet(this, -produced);
} else {
r = Long.MAX_VALUE;
}
is.requestMore(produced);
}
if (r == 0 || o == null) {
break;
}
}
boolean innerDone = is.done;
Queue innerQueue = is.queue;
if (innerDone && (innerQueue == null || innerQueue.isEmpty())) {
removeInner(is);
if (checkTerminate()) {
return;
}
replenishMain++;
innerCompleted = true;
}
if (r == 0L) {
break;
}
j++;
if (j == n) {
j = 0;
}
}
lastIndex = j;
lastId = inner[j].id;
}
if (replenishMain != 0L && !cancelled) {
s.request(replenishMain);
}
if (innerCompleted) {
continue;
}
missed = addAndGet(-missed);
if (missed == 0) {
break;
}
}
}
boolean checkTerminate() {
if (cancelled) {
s.cancel();
unsubscribe();
return true;
}
Queue e = errors;
if (!delayErrors && (e != null && !e.isEmpty())) {
try {
reportError(e);
} finally {
unsubscribe();
}
return true;
}
return false;
}
void reportError(Queue q) {
CompositeException composite = null;
Throwable ex = null;
Throwable t;
int count = 0;
while ((t = q.poll()) != null) {
if (count == 0) {
ex = t;
} else {
if (composite == null) {
composite = new CompositeException(ex);
}
composite.suppress(t);
}
count++;
}
if (composite != null) {
actual.onError(composite);
} else {
actual.onError(ex);
}
}
void unsubscribe() {
InnerSubscriber[] a = subscribers;
if (a != CANCELLED) {
a = SUBSCRIBERS.getAndSet(this, CANCELLED);
if (a != CANCELLED) {
ERRORS.getAndSet(this, ERRORS_CLOSED);
for (InnerSubscriber inner : a) {
inner.dispose();
}
}
}
}
Queue getErrorQueue() {
for (;;) {
Queue q = errors;
if (q != null) {
return q;
}
q = new MpscLinkedQueue();
if (ERRORS.compareAndSet(this, null, q)) {
return q;
}
}
}
}
static final class InnerSubscriber extends AtomicReference
implements Subscriber, Disposable {
/** */
private static final long serialVersionUID = -4606175640614850599L;
final long id;
final MergeSubscriber parent;
final int limit;
final int bufferSize;
volatile boolean done;
volatile Queue queue;
int outstanding;
static final Subscription CANCELLED = new Subscription() {
@Override
public void request(long n) {
}
@Override
public void cancel() {
}
};
public InnerSubscriber(MergeSubscriber parent, long id) {
this.id = id;
this.parent = parent;
this.bufferSize = parent.bufferSize;
this.limit = bufferSize >> 2;
}
@Override
public void onSubscribe(Subscription s) {
if (!compareAndSet(null, s)) {
s.cancel();
if (get() != CANCELLED) {
SubscriptionHelper.reportSubscriptionSet();
}
return;
}
outstanding = bufferSize;
s.request(outstanding);
}
@Override
public void onNext(U t) {
parent.tryEmit(t, this);
}
@Override
public void onError(Throwable t) {
parent.getErrorQueue().offer(t);
done = true;
parent.drain();
}
@Override
public void onComplete() {
done = true;
parent.drain();
}
void requestMore(long n) {
int r = outstanding - (int)n;
if (r > limit) {
outstanding = r;
return;
}
outstanding = bufferSize;
int k = bufferSize - r;
if (k > 0) {
get().request(k);
}
}
@Override
public void dispose() {
Subscription s = get();
if (s != CANCELLED) {
s = getAndSet(CANCELLED);
if (s != CANCELLED && s != null) {
s.cancel();
}
}
}
}
static final class RejectingQueue extends AbstractQueue {
@Override
public boolean offer(T e) {
return false;
}
@Override
public T poll() {
return null;
}
@Override
public T peek() {
return null;
}
@Override
public Iterator iterator() {
return Collections.emptyList().iterator();
}
@Override
public int size() {
return 0;
}
}
}
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