/*
* Copyright (c) 2011-2017 Pivotal Software Inc, All Rights Reserved.
*
* 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 reactor.core.publisher;
import java.util.
Objects;
import java.util.
Queue;
import java.util.concurrent.atomic.
AtomicIntegerFieldUpdater;
import java.util.concurrent.atomic.
AtomicReferenceFieldUpdater;
import java.util.function.
BiPredicate;
import java.util.stream.
Stream;
import org.reactivestreams.
Publisher;
import org.reactivestreams.
Subscription;
import reactor.core.
CoreSubscriber;
import reactor.core.
Exceptions;
import reactor.core.
Scannable;
import reactor.util.annotation.
Nullable;
import reactor.util.concurrent.
Queues;
import reactor.util.context.
Context;
import static reactor.core.publisher.
Operators.cancelledSubscription;
final class
MonoSequenceEqual<T> extends
Mono<
Boolean> implements
SourceProducer<
Boolean> {
final
Publisher<? extends T>
first;
final
Publisher<? extends T>
second;
final
BiPredicate<? super T, ? super T>
comparer;
final int
prefetch;
MonoSequenceEqual(
Publisher<? extends T>
first,
Publisher<? extends T>
second,
BiPredicate<? super T, ? super T>
comparer, int
prefetch) {
this.
first =
Objects.
requireNonNull(
first, "first");
this.
second =
Objects.
requireNonNull(
second, "second");
this.
comparer =
Objects.
requireNonNull(
comparer, "comparer");
if(
prefetch < 1){
throw new
IllegalArgumentException("Buffer size must be strictly positive: " +
""+
prefetch);
}
this.
prefetch =
prefetch;
}
@
Override
public void
subscribe(
CoreSubscriber<? super
Boolean>
actual) {
EqualCoordinator<T>
ec = new
EqualCoordinator<>(
actual,
prefetch,
first,
second,
comparer);
actual.
onSubscribe(
ec);
ec.
subscribe();
}
@
Override
public
Object scanUnsafe(
Attr key) {
if (
key ==
Attr.
PREFETCH) return
prefetch;
return null;
}
static final class
EqualCoordinator<T> implements
InnerProducer<
Boolean> {
final
CoreSubscriber<? super
Boolean>
actual;
final
BiPredicate<? super T, ? super T>
comparer;
final
Publisher<? extends T>
first;
final
Publisher<? extends T>
second;
final
EqualSubscriber<T>
firstSubscriber;
final
EqualSubscriber<T>
secondSubscriber;
volatile boolean
cancelled;
volatile int
once;
@
SuppressWarnings("rawtypes")
static final
AtomicIntegerFieldUpdater<
EqualCoordinator>
ONCE =
AtomicIntegerFieldUpdater.
newUpdater(
EqualCoordinator.class, "once");
T
v1;
T
v2;
volatile int
wip;
@
SuppressWarnings("rawtypes")
static final
AtomicIntegerFieldUpdater<
EqualCoordinator>
WIP =
AtomicIntegerFieldUpdater.
newUpdater(
EqualCoordinator.class, "wip");
EqualCoordinator(
CoreSubscriber<? super
Boolean>
actual, int
prefetch,
Publisher<? extends T>
first,
Publisher<? extends T>
second,
BiPredicate<? super T, ? super T>
comparer) {
this.
actual =
actual;
this.
first =
first;
this.
second =
second;
this.
comparer =
comparer;
firstSubscriber = new
EqualSubscriber<>(this,
prefetch);
secondSubscriber = new
EqualSubscriber<>(this,
prefetch);
}
@
Override
public
CoreSubscriber<? super
Boolean>
actual() {
return
actual;
}
@
Override
@
Nullable
public
Object scanUnsafe(
Attr key) {
if (
key ==
Attr.
CANCELLED) return
cancelled;
return
InnerProducer.super.scanUnsafe(
key);
}
@
Override
public
Stream<? extends
Scannable>
inners() {
return
Stream.
of(
firstSubscriber,
secondSubscriber);
}
void
subscribe() {
if (
ONCE.
compareAndSet(this, 0, 1)) {
first.
subscribe(
firstSubscriber);
second.
subscribe(
secondSubscriber);
}
}
@
Override
public void
request(long
n) {
if (!
Operators.
validate(
n)) {
return;
}
if (
ONCE.
compareAndSet(this, 0, 1)) {
first.
subscribe(
firstSubscriber);
second.
subscribe(
secondSubscriber);
}
}
@
Override
public void
cancel() {
if (!
cancelled) {
cancelled = true;
cancelInner(
firstSubscriber);
cancelInner(
secondSubscriber);
if (
WIP.
getAndIncrement(this) == 0) {
firstSubscriber.
queue.
clear();
secondSubscriber.
queue.
clear();
}
}
}
void
cancel(
EqualSubscriber<T>
s1,
Queue<T>
q1,
EqualSubscriber<T>
s2,
Queue<T>
q2) {
cancelled = true;
cancelInner(
s1);
q1.
clear();
cancelInner(
s2);
q2.
clear();
}
void
cancelInner(
EqualSubscriber<T>
innerSubscriber) {
Subscription s =
innerSubscriber.
subscription;
if (
s !=
cancelledSubscription()) {
s =
EqualSubscriber.
S.
getAndSet(
innerSubscriber,
cancelledSubscription());
if (
s != null &&
s !=
cancelledSubscription()) {
s.
cancel();
}
}
}
void
drain() {
if (
WIP.
getAndIncrement(this) != 0) {
return;
}
int
missed = 1;
final
EqualSubscriber<T>
s1 =
firstSubscriber;
final
Queue<T>
q1 =
s1.
queue;
final
EqualSubscriber<T>
s2 =
secondSubscriber;
final
Queue<T>
q2 =
s2.
queue;
for (;;) {
long
r = 0L;
for (;;) {
if (
cancelled) {
q1.
clear();
q2.
clear();
return;
}
boolean
d1 =
s1.
done;
if (
d1) {
Throwable e =
s1.
error;
if (
e != null) {
cancel(
s1,
q1,
s2,
q2);
actual.
onError(
e);
return;
}
}
boolean
d2 =
s2.
done;
if (
d2) {
Throwable e =
s2.
error;
if (
e != null) {
cancel(
s1,
q1,
s2,
q2);
actual.
onError(
e);
return;
}
}
if (
v1 == null) {
v1 =
q1.
poll();
}
boolean
e1 =
v1 == null;
if (
v2 == null) {
v2 =
q2.
poll();
}
boolean
e2 =
v2 == null;
if (
d1 &&
d2 &&
e1 &&
e2) {
actual.
onNext(true);
actual.
onComplete();
return;
}
if ((
d1 &&
d2) && (
e1 !=
e2)) {
cancel(
s1,
q1,
s2,
q2);
actual.
onNext(false);
actual.
onComplete();
return;
}
if (!
e1 && !
e2) {
boolean
c;
try {
c =
comparer.
test(
v1,
v2);
} catch (
Throwable ex) {
Exceptions.
throwIfFatal(
ex);
cancel(
s1,
q1,
s2,
q2);
actual.
onError(
Operators.
onOperatorError(
ex,
actual.
currentContext()));
return;
}
if (!
c) {
cancel(
s1,
q1,
s2,
q2);
actual.
onNext(false);
actual.
onComplete();
return;
}
r++;
v1 = null;
v2 = null;
}
if (
e1 ||
e2) {
break;
}
}
if (
r != 0L) {
s1.
cachedSubscription.
request(
r);
s2.
cachedSubscription.
request(
r);
}
missed =
WIP.
addAndGet(this, -
missed);
if (
missed == 0) {
break;
}
}
}
}
static final class
EqualSubscriber<T>
implements
InnerConsumer<T> {
final
EqualCoordinator<T>
parent;
final
Queue<T>
queue;
final int
prefetch;
volatile boolean
done;
Throwable error;
Subscription cachedSubscription;
volatile
Subscription subscription;
static final
AtomicReferenceFieldUpdater<
EqualSubscriber,
Subscription>
S =
AtomicReferenceFieldUpdater.
newUpdater(
EqualSubscriber.class,
Subscription.class, "subscription");
EqualSubscriber(
EqualCoordinator<T>
parent, int
prefetch) {
this.
parent =
parent;
this.
prefetch =
prefetch;
this.
queue =
Queues.<T>
get(
prefetch).
get();
}
@
Override
public
Context currentContext() {
return
parent.
actual.
currentContext();
}
@
Override
@
Nullable
public
Object scanUnsafe(
Attr key) {
if (
key ==
Attr.
TERMINATED) return
done;
if (
key ==
Attr.
ACTUAL) return
parent;
if (
key ==
Attr.
ERROR) return
error;
if (
key ==
Attr.
CANCELLED) return
subscription ==
Operators.
cancelledSubscription();
if (
key ==
Attr.
PARENT) return
subscription;
if (
key ==
Attr.
PREFETCH) return
prefetch;
if (
key ==
Attr.
BUFFERED) return
queue.
size();
return null;
}
@
Override
public void
onSubscribe(
Subscription s) {
if (
Operators.
setOnce(
S, this,
s)) {
this.
cachedSubscription =
s;
s.
request(
Operators.
unboundedOrPrefetch(
prefetch));
}
}
@
Override
public void
onNext(T
t) {
if (!
queue.
offer(
t)) {
onError(
Operators.
onOperatorError(
cachedSubscription,
Exceptions
.
failWithOverflow(
Exceptions.
BACKPRESSURE_ERROR_QUEUE_FULL),
t,
currentContext()));
return;
}
parent.
drain();
}
@
Override
public void
onError(
Throwable t) {
error =
t;
done = true;
parent.
drain();
}
@
Override
public void
onComplete() {
done = true;
parent.
drain();
}
}
}