/*
* 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.
Collection;
import java.util.
Objects;
import java.util.concurrent.atomic.
AtomicLongFieldUpdater;
import java.util.concurrent.atomic.
AtomicReferenceFieldUpdater;
import java.util.function.
Supplier;
import org.reactivestreams.
Publisher;
import org.reactivestreams.
Subscription;
import reactor.core.
CoreSubscriber;
import reactor.core.
Exceptions;
import reactor.util.annotation.
Nullable;
import reactor.util.context.
Context;
/**
* Buffers elements into custom collections where the buffer boundary is signalled
* by another publisher.
*
* @param <T> the source value type
* @param <U> the element type of the boundary publisher (irrelevant)
* @param <C> the output collection type
*
* @see <a href="https://github.com/reactor/reactive-streams-commons">Reactive-Streams-Commons</a>
*/
final class
FluxBufferBoundary<T, U, C extends
Collection<? super T>>
extends
FluxOperator<T, C> {
final
Publisher<U>
other;
final
Supplier<C>
bufferSupplier;
FluxBufferBoundary(
Flux<? extends T>
source,
Publisher<U>
other,
Supplier<C>
bufferSupplier) {
super(
source);
this.
other =
Objects.
requireNonNull(
other, "other");
this.
bufferSupplier =
Objects.
requireNonNull(
bufferSupplier, "bufferSupplier");
}
@
Override
public int
getPrefetch() {
return
Integer.
MAX_VALUE;
}
@
Override
public void
subscribe(
CoreSubscriber<? super C>
actual) {
C
buffer;
try {
buffer =
Objects.
requireNonNull(
bufferSupplier.
get(),
"The bufferSupplier returned a null buffer");
}
catch (
Throwable e) {
Operators.
error(
actual,
Operators.
onOperatorError(
e,
actual.
currentContext()));
return;
}
BufferBoundaryMain<T, U, C>
parent =
new
BufferBoundaryMain<>(
source instanceof
FluxInterval ?
actual :
Operators.
serialize(
actual),
buffer,
bufferSupplier);
actual.
onSubscribe(
parent);
other.
subscribe(
parent.
other);
source.
subscribe(
parent);
}
static final class
BufferBoundaryMain<T, U, C extends
Collection<? super T>>
implements
InnerOperator<T, C> {
final
Supplier<C>
bufferSupplier;
final
CoreSubscriber<? super C>
actual;
final
Context ctx;
final
BufferBoundaryOther<U>
other;
C
buffer;
volatile
Subscription s;
@
SuppressWarnings("rawtypes")
static final
AtomicReferenceFieldUpdater<
BufferBoundaryMain,
Subscription>
S =
AtomicReferenceFieldUpdater.
newUpdater(
BufferBoundaryMain.class,
Subscription.class,
"s");
volatile long
requested;
@
SuppressWarnings("rawtypes")
static final
AtomicLongFieldUpdater<
BufferBoundaryMain>
REQUESTED =
AtomicLongFieldUpdater.
newUpdater(
BufferBoundaryMain.class, "requested");
BufferBoundaryMain(
CoreSubscriber<? super C>
actual,
C
buffer,
Supplier<C>
bufferSupplier) {
this.
actual =
actual;
this.
ctx =
actual.
currentContext();
this.
buffer =
buffer;
this.
bufferSupplier =
bufferSupplier;
this.
other = new
BufferBoundaryOther<>(this);
}
@
Override
public
CoreSubscriber<? super C>
actual() {
return
actual;
}
@
Override
@
Nullable
public
Object scanUnsafe(
Attr key) {
if (
key ==
Attr.
PARENT) return
s;
if (
key ==
Attr.
CANCELLED) return
s ==
Operators.
cancelledSubscription();
if (
key ==
Attr.
CAPACITY) {
C
buffer = this.
buffer;
return
buffer != null ?
buffer.
size() : 0;
}
if (
key ==
Attr.
PREFETCH) return
Integer.
MAX_VALUE;
if (
key ==
Attr.
REQUESTED_FROM_DOWNSTREAM) return
requested;
return
InnerOperator.super.scanUnsafe(
key);
}
@
Override
public void
request(long
n) {
if (
Operators.
validate(
n)) {
Operators.
addCap(
REQUESTED, this,
n);
}
}
@
Override
public void
cancel() {
Operators.
terminate(
S, this);
Operators.
onDiscardMultiple(
buffer, this.
ctx);
other.
cancel();
}
@
Override
public void
onSubscribe(
Subscription s) {
if (
Operators.
setOnce(
S, this,
s)) {
s.
request(
Long.
MAX_VALUE);
}
}
@
Override
public void
onNext(T
t) {
synchronized (this) {
C
b =
buffer;
if (
b != null) {
b.
add(
t);
return;
}
}
Operators.
onNextDropped(
t, this.
ctx);
}
@
Override
public void
onError(
Throwable t) {
if(
Operators.
terminate(
S, this)) {
C
b;
synchronized (this) {
b =
buffer;
buffer = null;
}
other.
cancel();
actual.
onError(
t);
Operators.
onDiscardMultiple(
b, this.
ctx);
return;
}
Operators.
onErrorDropped(
t, this.
ctx);
}
@
Override
public void
onComplete() {
if(
Operators.
terminate(
S, this)) {
C
b;
synchronized (this) {
b =
buffer;
buffer = null;
}
other.
cancel();
if (!
b.
isEmpty()) {
if (
emit(
b)) {
actual.
onComplete();
} //failed emit will discard buffer's elements
}
else {
actual.
onComplete();
}
}
}
void
otherComplete() {
Subscription s =
S.
getAndSet(this,
Operators.
cancelledSubscription());
if(
s !=
Operators.
cancelledSubscription()) {
C
b;
synchronized (this) {
b =
buffer;
buffer = null;
}
if(
s != null){
s.
cancel();
}
if (
b != null && !
b.
isEmpty()) {
if (
emit(
b)) {
actual.
onComplete();
} //failed emit will discard buffer content
}
else {
actual.
onComplete();
}
}
}
void
otherError(
Throwable t){
Subscription s =
S.
getAndSet(this,
Operators.
cancelledSubscription());
if(
s !=
Operators.
cancelledSubscription()) {
C
b;
synchronized (this) {
b =
buffer;
buffer = null;
}
if(
s != null){
s.
cancel();
}
actual.
onError(
t);
Operators.
onDiscardMultiple(
b, this.
ctx);
return;
}
Operators.
onErrorDropped(
t, this.
ctx);
}
void
otherNext() {
C
c;
try {
c =
Objects.
requireNonNull(
bufferSupplier.
get(),
"The bufferSupplier returned a null buffer");
}
catch (
Throwable e) {
otherError(
Operators.
onOperatorError(
other,
e, this.
ctx));
return;
}
C
b;
synchronized (this) {
b =
buffer;
buffer =
c;
}
if (
b == null ||
b.
isEmpty()) {
return;
}
emit(
b);
}
boolean
emit(C
b) {
long
r =
requested;
if (
r != 0L) {
actual.
onNext(
b);
if (
r !=
Long.
MAX_VALUE) {
REQUESTED.
decrementAndGet(this);
}
return true;
}
else {
actual.
onError(
Operators.
onOperatorError(this,
Exceptions
.
failWithOverflow(),
b, this.
ctx));
Operators.
onDiscardMultiple(
b, this.
ctx);
return false;
}
}
}
static final class
BufferBoundaryOther<U> extends
Operators.
DeferredSubscription
implements
InnerConsumer<U> {
final
BufferBoundaryMain<?, U, ?>
main;
BufferBoundaryOther(
BufferBoundaryMain<?, U, ?>
main) {
this.
main =
main;
}
@
Override
public void
onSubscribe(
Subscription s) {
if (
set(
s)) {
s.
request(
Long.
MAX_VALUE);
}
}
@
Override
public
Context currentContext() {
return
main.
currentContext();
}
@
Override
@
Nullable
public
Object scanUnsafe(
Attr key) {
if (
key ==
Attr.
ACTUAL) {
return
main;
}
return super.scanUnsafe(
key);
}
@
Override
public void
onNext(U
t) {
main.
otherNext();
}
@
Override
public void
onError(
Throwable t) {
main.
otherError(
t);
}
@
Override
public void
onComplete() {
main.
otherComplete();
}
}
}