/*
* Copyright (c) 2011-2018 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.
AtomicLongFieldUpdater;
import java.util.concurrent.atomic.
AtomicReferenceFieldUpdater;
import java.util.function.
Predicate;
import java.util.function.
Supplier;
import java.util.stream.
Stream;
import org.reactivestreams.
Subscriber;
import org.reactivestreams.
Subscription;
import reactor.core.
CoreSubscriber;
import reactor.core.
Exceptions;
import reactor.core.
Fuseable;
import reactor.core.
Scannable;
import reactor.core.publisher.
FluxBufferPredicate.
Mode;
import reactor.util.annotation.
Nullable;
import reactor.util.context.
Context;
/**
* Cut a sequence into non-overlapping windows where each window boundary is determined by
* a {@link Predicate} on the values. The predicate can be used in several modes:
* <ul>
* <li>{@code Until}: A new window starts when the predicate returns true. The
* element that just matched the predicate is the last in the previous window, and the
* windows are not emitted before an inner element is pushed.</li>
* <li>{@code UntilOther}: A new window starts when the predicate returns true. The
* element that just matched the predicate is the first in the new window, which is
* emitted immediately.</li>
* <li>{@code While}: A new window starts when the predicate stops matching. The
* non-matching elements that delimit each window are simply discarded, and the
* windows are not emitted before an inner element is pushed</li>
* </ul>
*
* @param <T> the source and window value type
*
* @see <a href="https://github.com/reactor/reactive-streams-commons">Reactive-Streams-Commons</a>
*/
final class
FluxWindowPredicate<T> extends
FluxOperator<T,
Flux<T>>
implements
Fuseable{
final
Supplier<? extends
Queue<T>>
groupQueueSupplier;
final
Supplier<? extends
Queue<
Flux<T>>>
mainQueueSupplier;
final
Mode mode;
final
Predicate<? super T>
predicate;
final int
prefetch;
FluxWindowPredicate(
Flux<? extends T>
source,
Supplier<? extends
Queue<
Flux<T>>>
mainQueueSupplier,
Supplier<? extends
Queue<T>>
groupQueueSupplier,
int
prefetch,
Predicate<? super T>
predicate,
Mode mode) {
super(
source);
if (
prefetch <= 0) {
throw new
IllegalArgumentException("prefetch > 0 required but it was " +
prefetch);
}
this.
predicate =
Objects.
requireNonNull(
predicate, "predicate");
this.
mainQueueSupplier =
Objects.
requireNonNull(
mainQueueSupplier, "mainQueueSupplier");
this.
groupQueueSupplier =
Objects.
requireNonNull(
groupQueueSupplier, "groupQueueSupplier");
this.
mode =
mode;
this.
prefetch =
prefetch;
}
@
Override
public void
subscribe(
CoreSubscriber<? super
Flux<T>>
actual) {
source.
subscribe(new
WindowPredicateMain<>(
actual,
mainQueueSupplier.
get(),
groupQueueSupplier,
prefetch,
predicate,
mode));
}
@
Override
public int
getPrefetch() {
return
prefetch;
}
static final class
WindowPredicateMain<T>
implements
Fuseable.
QueueSubscription<
Flux<T>>,
InnerOperator<T,
Flux<T>> {
final
CoreSubscriber<? super
Flux<T>>
actual;
final
Context ctx;
final
Supplier<? extends
Queue<T>>
groupQueueSupplier;
final
Mode mode;
final
Predicate<? super T>
predicate;
final int
prefetch;
final
Queue<
Flux<T>>
queue;
WindowFlux<T>
window;
volatile int
wip;
@
SuppressWarnings("rawtypes")
static final
AtomicIntegerFieldUpdater<
WindowPredicateMain>
WIP =
AtomicIntegerFieldUpdater.
newUpdater(
WindowPredicateMain.class, "wip");
volatile long
requested;
@
SuppressWarnings("rawtypes")
static final
AtomicLongFieldUpdater<
WindowPredicateMain>
REQUESTED =
AtomicLongFieldUpdater.
newUpdater(
WindowPredicateMain.class, "requested");
volatile boolean
done;
volatile
Throwable error;
@
SuppressWarnings("rawtypes")
static final
AtomicReferenceFieldUpdater<
WindowPredicateMain,
Throwable>
ERROR =
AtomicReferenceFieldUpdater.
newUpdater(
WindowPredicateMain.class,
Throwable.class,
"error");
volatile int
cancelled;
@
SuppressWarnings("rawtypes")
static final
AtomicIntegerFieldUpdater<
WindowPredicateMain>
CANCELLED =
AtomicIntegerFieldUpdater.
newUpdater(
WindowPredicateMain.class,
"cancelled");
volatile int
windowCount;
@
SuppressWarnings("rawtypes")
static final
AtomicIntegerFieldUpdater<
WindowPredicateMain>
WINDOW_COUNT =
AtomicIntegerFieldUpdater.
newUpdater(
WindowPredicateMain.class, "windowCount");
Subscription s;
volatile boolean
outputFused;
WindowPredicateMain(
CoreSubscriber<? super
Flux<T>>
actual,
Queue<
Flux<T>>
queue,
Supplier<? extends
Queue<T>>
groupQueueSupplier,
int
prefetch,
Predicate<? super T>
predicate,
Mode mode) {
this.
actual =
actual;
this.
ctx =
actual.
currentContext();
this.
queue =
queue;
this.
groupQueueSupplier =
groupQueueSupplier;
this.
prefetch =
prefetch;
this.
predicate =
predicate;
this.
mode =
mode;
WINDOW_COUNT.
lazySet(this, 2);
initializeWindow();
}
@
Override
public void
onSubscribe(
Subscription s) {
if (
Operators.
validate(this.
s,
s)) {
this.
s =
s;
actual.
onSubscribe(this);
if (
cancelled == 0) {
s.
request(
Operators.
unboundedOrPrefetch(
prefetch));
}
}
}
void
initializeWindow() {
WindowFlux<T>
g = new
WindowFlux<>(
groupQueueSupplier.
get(),
this);
window =
g;
}
@
Nullable WindowFlux<T>
newWindowDeferred() {
// if the main is cancelled, don't create new groups
if (
cancelled == 0) {
WINDOW_COUNT.
getAndIncrement(this);
WindowFlux<T>
g = new
WindowFlux<>(
groupQueueSupplier.
get(), this);
window =
g;
return
g;
}
return null;
}
@
Override
public void
onNext(T
t) {
if (
done) {
Operators.
onNextDropped(
t,
ctx);
return;
}
WindowFlux<T>
g =
window;
boolean
match;
try {
match =
predicate.
test(
t);
}
catch (
Throwable e) {
onError(
Operators.
onOperatorError(
s,
e,
t,
ctx));
return;
}
if (!
handleDeferredWindow(
g,
t)) {
return;
}
drain();
if (
mode ==
Mode.
UNTIL &&
match) {
g.
onNext(
t);
g.
onComplete();
newWindowDeferred();
}
else if (
mode ==
Mode.
UNTIL_CUT_BEFORE &&
match) {
g.
onComplete();
g =
newWindowDeferred();
if (
g != null) {
g.
onNext(
t);
handleDeferredWindow(
g,
t);
drain();
}
}
else if (
mode ==
Mode.
WHILE && !
match) {
g.
onComplete();
newWindowDeferred();
Operators.
onDiscard(
t,
ctx);
//compensate for the dropped delimiter
s.
request(1);
}
else {
g.
onNext(
t);
}
}
boolean
handleDeferredWindow(@
Nullable WindowFlux<T>
window, T
signal) {
if (
window != null &&
window.
deferred) {
window.
deferred = false;
if (!
queue.
offer(
window)) {
onError(
Operators.
onOperatorError(this,
Exceptions.
failWithOverflow(
Exceptions.
BACKPRESSURE_ERROR_QUEUE_FULL),
signal,
ctx));
return false;
}
}
return true;
}
@
Override
public void
onError(
Throwable t) {
if (
Exceptions.
addThrowable(
ERROR, this,
t)) {
done = true;
drain();
}
else {
Operators.
onErrorDropped(
t,
ctx);
}
}
@
Override
public void
onComplete() {
if(
done) {
return;
}
WindowFlux<T>
g =
window;
if (
g != null) {
g.
onComplete();
}
window = null;
done = true;
WINDOW_COUNT.
decrementAndGet(this);
drain();
}
@
Override
@
Nullable
public
Object scanUnsafe(
Attr key) {
if (
key ==
Attr.
PARENT) return
s;
if (
key ==
Attr.
CANCELLED) return
cancelled == 1;
if (
key ==
Attr.
PREFETCH) return
prefetch;
if (
key ==
Attr.
TERMINATED) return
done;
if (
key ==
Attr.
BUFFERED) return
queue.
size();
if (
key ==
Attr.
ERROR) return
error;
if (
key ==
Attr.
REQUESTED_FROM_DOWNSTREAM) return
requested;
return
InnerOperator.super.scanUnsafe(
key);
}
@
Override
public
Stream<? extends
Scannable>
inners() {
return
window == null ?
Stream.
empty() :
Stream.
of(
window);
}
@
Override
public
CoreSubscriber<? super
Flux<T>>
actual() {
return
actual;
}
void
signalAsyncError() {
Throwable e =
Exceptions.
terminate(
ERROR, this);
windowCount = 0;
WindowFlux<T>
g =
window;
if (
g != null) {
g.
onError(
e);
}
actual.
onError(
e);
window = null;
}
@
Override
public void
request(long
n) {
if (
Operators.
validate(
n)) {
Operators.
addCap(
REQUESTED, this,
n);
drain();
}
}
@
Override
public void
cancel() {
if (
CANCELLED.
compareAndSet(this, 0, 1)) {
if (
WINDOW_COUNT.
decrementAndGet(this) == 0) {
s.
cancel();
}
else if (!
outputFused) {
if (
WIP.
getAndIncrement(this) == 0) {
// remove queued up but unobservable groups from the mapping
Flux<T>
g;
while ((
g =
queue.
poll()) != null) {
((
WindowFlux<T>)
g).
cancel();
}
if (
WIP.
decrementAndGet(this) == 0) {
return;
}
drainLoop();
}
}
}
}
void
groupTerminated() {
if (
windowCount == 0) {
return;
}
window = null;
if (
WINDOW_COUNT.
decrementAndGet(this) == 0) {
s.
cancel();
}
}
void
drain() {
if (
WIP.
getAndIncrement(this) != 0) {
return;
}
if (
outputFused) {
drainFused();
}
else {
drainLoop();
}
}
void
drainFused() {
int
missed = 1;
final
Subscriber<? super
Flux<T>>
a =
actual;
final
Queue<
Flux<T>>
q =
queue;
for (; ; ) {
if (
cancelled != 0) {
q.
clear();
return;
}
boolean
d =
done;
a.
onNext(null);
if (
d) {
Throwable ex =
error;
if (
ex != null) {
signalAsyncError();
}
else {
a.
onComplete();
}
return;
}
missed =
WIP.
addAndGet(this, -
missed);
if (
missed == 0) {
break;
}
}
}
void
drainLoop() {
int
missed = 1;
Subscriber<? super
Flux<T>>
a =
actual;
Queue<
Flux<T>>
q =
queue;
for (; ; ) {
long
r =
requested;
long
e = 0L;
while (
e !=
r) {
boolean
d =
done;
Flux<T>
v =
q.
poll();
boolean
empty =
v == null;
if (
checkTerminated(
d,
empty,
a,
q)) {
return;
}
if (
empty) {
break;
}
a.
onNext(
v);
e++;
}
if (
e ==
r) {
if (
checkTerminated(
done,
q.
isEmpty(),
a,
q)) {
return;
}
}
if (
e != 0L) {
s.
request(
e);
if (
r !=
Long.
MAX_VALUE) {
REQUESTED.
addAndGet(this, -
e);
}
}
missed =
WIP.
addAndGet(this, -
missed);
if (
missed == 0) {
break;
}
}
}
boolean
checkTerminated(boolean
d,
boolean
empty,
Subscriber<?>
a,
Queue<
Flux<T>>
q) {
if (
cancelled != 0) {
q.
clear();
return true;
}
if (
d) {
Throwable e =
error;
if (
e != null &&
e !=
Exceptions.
TERMINATED) {
queue.
clear();
signalAsyncError();
return true;
}
else if (
empty) {
a.
onComplete();
return true;
}
}
return false;
}
@
Override
@
Nullable
public
Flux<T>
poll() {
return
queue.
poll();
}
@
Override
public int
size() {
return
queue.
size();
}
@
Override
public boolean
isEmpty() {
return
queue.
isEmpty();
}
@
Override
public void
clear() {
queue.
clear();
}
@
Override
public int
requestFusion(int
requestedMode) {
if ((
requestedMode &
Fuseable.
ASYNC) != 0) {
outputFused = true;
return
Fuseable.
ASYNC;
}
return
Fuseable.
NONE;
}
}
static final class
WindowFlux<T> extends
Flux<T>
implements
Fuseable,
Fuseable.
QueueSubscription<T>,
InnerOperator<T, T> {
final
Queue<T>
queue;
volatile
WindowPredicateMain<T>
parent;
@
SuppressWarnings("rawtypes")
static final
AtomicReferenceFieldUpdater<
WindowFlux,
WindowPredicateMain>
PARENT =
AtomicReferenceFieldUpdater.
newUpdater(
WindowFlux.class,
WindowPredicateMain.class,
"parent");
volatile boolean
done;
Throwable error;
volatile
CoreSubscriber<? super T>
actual;
@
SuppressWarnings("rawtypes")
static final
AtomicReferenceFieldUpdater<
WindowFlux,
CoreSubscriber>
ACTUAL =
AtomicReferenceFieldUpdater.
newUpdater(
WindowFlux.class,
CoreSubscriber.class,
"actual");
volatile
Context ctx =
Context.
empty();
volatile boolean
cancelled;
volatile int
once;
@
SuppressWarnings("rawtypes")
static final
AtomicIntegerFieldUpdater<
WindowFlux>
ONCE =
AtomicIntegerFieldUpdater.
newUpdater(
WindowFlux.class, "once");
volatile int
wip;
@
SuppressWarnings("rawtypes")
static final
AtomicIntegerFieldUpdater<
WindowFlux>
WIP =
AtomicIntegerFieldUpdater.
newUpdater(
WindowFlux.class, "wip");
volatile long
requested;
@
SuppressWarnings("rawtypes")
static final
AtomicLongFieldUpdater<
WindowFlux>
REQUESTED =
AtomicLongFieldUpdater.
newUpdater(
WindowFlux.class, "requested");
volatile boolean
enableOperatorFusion;
int
produced;
boolean
deferred;
WindowFlux(
Queue<T>
queue,
WindowPredicateMain<T>
parent) {
this.
queue =
queue;
this.
parent =
parent;
this.
deferred = true;
}
@
Override
public
CoreSubscriber<? super T>
actual() {
return
actual;
}
void
propagateTerminate() {
WindowPredicateMain<T>
r =
parent;
if (
r != null &&
PARENT.
compareAndSet(this,
r, null)) {
r.
groupTerminated();
}
}
void
drainRegular(
Subscriber<? super T>
a) {
int
missed = 1;
final
Queue<T>
q =
queue;
for (; ; ) {
long
r =
requested;
long
e = 0L;
while (
r !=
e) {
boolean
d =
done;
T
t =
q.
poll();
boolean
empty =
t == null;
if (
checkTerminated(
d,
empty,
a,
q)) {
return;
}
if (
empty) {
break;
}
a.
onNext(
t);
e++;
}
if (
r ==
e) {
if (
checkTerminated(
done,
q.
isEmpty(),
a,
q)) {
return;
}
}
if (
e != 0) {
WindowPredicateMain<T>
main =
parent;
if (
main != null) {
main.
s.
request(
e);
}
if (
r !=
Long.
MAX_VALUE) {
REQUESTED.
addAndGet(this, -
e);
}
}
missed =
WIP.
addAndGet(this, -
missed);
if (
missed == 0) {
break;
}
}
}
void
drainFused(
Subscriber<? super T>
a) {
int
missed = 1;
final
Queue<T>
q =
queue;
for (; ; ) {
if (
cancelled) {
Operators.
onDiscardQueueWithClear(
q,
ctx, null);
ctx =
Context.
empty();
actual = null;
return;
}
boolean
d =
done;
a.
onNext(null);
if (
d) {
ctx =
Context.
empty();
actual = null;
Throwable ex =
error;
if (
ex != null) {
a.
onError(
ex);
}
else {
a.
onComplete();
}
return;
}
missed =
WIP.
addAndGet(this, -
missed);
if (
missed == 0) {
break;
}
}
}
void
drain() {
Subscriber<? super T>
a =
actual;
if (
a != null) {
if (
WIP.
getAndIncrement(this) != 0) {
return;
}
if (
enableOperatorFusion) {
drainFused(
a);
}
else {
drainRegular(
a);
}
}
}
boolean
checkTerminated(boolean
d, boolean
empty,
Subscriber<?>
a,
Queue<?>
q) {
if (
cancelled) {
Operators.
onDiscardQueueWithClear(
q,
ctx, null);
ctx =
Context.
empty();
actual = null;
return true;
}
if (
d &&
empty) {
Throwable e =
error;
ctx =
Context.
empty();
actual = null;
if (
e != null) {
a.
onError(
e);
}
else {
a.
onComplete();
}
return true;
}
return false;
}
public void
onNext(T
t) {
Subscriber<? super T>
a =
actual;
if (!
queue.
offer(
t)) {
onError(
Operators.
onOperatorError(this,
Exceptions.
failWithOverflow(
Exceptions.
BACKPRESSURE_ERROR_QUEUE_FULL),
t,
ctx));
return;
}
if (
enableOperatorFusion) {
if (
a != null) {
a.
onNext(null); // in op-fusion, onNext(null) is the indicator of more data
}
}
else {
drain();
}
}
@
Override
public void
onSubscribe(
Subscription s) {
//IGNORE
}
@
Override
public void
onError(
Throwable t) {
error =
t;
done = true;
propagateTerminate();
drain();
}
@
Override
public void
onComplete() {
done = true;
propagateTerminate();
drain();
}
@
Override
public void
subscribe(
CoreSubscriber<? super T>
actual) {
if (
once == 0 &&
ONCE.
compareAndSet(this, 0, 1)) {
actual.
onSubscribe(this);
ACTUAL.
lazySet(this,
actual);
ctx =
actual.
currentContext();
drain();
}
else {
actual.
onError(new
IllegalStateException(
"This processor allows only a single Subscriber"));
}
}
@
Override
public void
request(long
n) {
if (
Operators.
validate(
n)) {
Operators.
addCap(
REQUESTED, this,
n);
drain();
}
}
@
Override
public void
cancel() {
if (
cancelled) {
return;
}
cancelled = true;
WindowPredicateMain<T>
r =
parent;
if (
r != null &&
PARENT.
compareAndSet(this,
r, null)) {
if (
WindowPredicateMain.
WINDOW_COUNT.
decrementAndGet(
r) == 0) {
r.
cancel();
}
else {
r.
s.
request(1);
}
}
if (!
enableOperatorFusion) {
if (
WIP.
getAndIncrement(this) == 0) {
Operators.
onDiscardQueueWithClear(
queue,
ctx, null);
}
}
}
@
Override
@
Nullable
public T
poll() {
T
v =
queue.
poll();
if (
v != null) {
produced++;
}
else {
int
p =
produced;
if (
p != 0) {
produced = 0;
WindowPredicateMain<T>
main =
parent;
if (
main != null) {
main.
s.
request(
p);
}
}
}
return
v;
}
@
Override
public int
size() {
return
queue.
size();
}
@
Override
public boolean
isEmpty() {
return
queue.
isEmpty();
}
@
Override
public void
clear() {
Operators.
onDiscardQueueWithClear(
queue,
ctx, null);
}
@
Override
public int
requestFusion(int
requestedMode) {
if ((
requestedMode &
Fuseable.
ASYNC) != 0) {
enableOperatorFusion = true;
return
Fuseable.
ASYNC;
}
return
Fuseable.
NONE;
}
@
Override
@
Nullable
public
Object scanUnsafe(
Attr key) {
if (
key ==
Attr.
PARENT) return
parent;
if (
key ==
Attr.
CANCELLED) return
cancelled;
if (
key ==
Attr.
TERMINATED) return
done;
if (
key ==
Attr.
BUFFERED) return
queue == null ? 0 :
queue.
size();
if (
key ==
Attr.
ERROR) return
error;
if (
key ==
Attr.
REQUESTED_FROM_DOWNSTREAM) return
requested;
return
InnerOperator.super.scanUnsafe(
key);
}
}
}