/*
* 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.
ArrayDeque;
import java.util.
Collection;
import java.util.
Objects;
import java.util.concurrent.atomic.
AtomicIntegerFieldUpdater;
import java.util.concurrent.atomic.
AtomicLongFieldUpdater;
import java.util.function.
BooleanSupplier;
import java.util.function.
Supplier;
import org.reactivestreams.
Subscription;
import reactor.core.
CoreSubscriber;
import reactor.util.annotation.
Nullable;
import reactor.util.context.
Context;
/**
* Buffers a certain number of subsequent elements and emits the buffers.
*
* @param <T> the source value type
* @param <C> the buffer collection type
*
* @see <a href="https://github.com/reactor/reactive-streams-commons">Reactive-Streams-Commons</a>
*/
final class
FluxBuffer<T, C extends
Collection<? super T>> extends
FluxOperator<T, C> {
final int
size;
final int
skip;
final
Supplier<C>
bufferSupplier;
FluxBuffer(
Flux<? extends T>
source, int
size,
Supplier<C>
bufferSupplier) {
this(
source,
size,
size,
bufferSupplier);
}
FluxBuffer(
Flux<? extends T>
source,
int
size,
int
skip,
Supplier<C>
bufferSupplier) {
super(
source);
if (
size <= 0) {
throw new
IllegalArgumentException("size > 0 required but it was " +
size);
}
if (
skip <= 0) {
throw new
IllegalArgumentException("skip > 0 required but it was " +
size);
}
this.
size =
size;
this.
skip =
skip;
this.
bufferSupplier =
Objects.
requireNonNull(
bufferSupplier, "bufferSupplier");
}
@
Override
public void
subscribe(
CoreSubscriber<? super C>
actual) {
if (
size ==
skip) {
source.
subscribe(new
BufferExactSubscriber<>(
actual,
size,
bufferSupplier));
}
else if (
skip >
size) {
source.
subscribe(new
BufferSkipSubscriber<>(
actual,
size,
skip,
bufferSupplier));
}
else {
source.
subscribe(new
BufferOverlappingSubscriber<>(
actual,
size,
skip,
bufferSupplier));
}
}
static final class
BufferExactSubscriber<T, C extends
Collection<? super T>>
implements
InnerOperator<T, C> {
final
CoreSubscriber<? super C>
actual;
final
Context ctx;
final
Supplier<C>
bufferSupplier;
final int
size;
C
buffer;
Subscription s;
boolean
done;
BufferExactSubscriber(
CoreSubscriber<? super C>
actual,
int
size,
Supplier<C>
bufferSupplier) {
this.
actual =
actual;
this.
ctx =
actual.
currentContext();
this.
size =
size;
this.
bufferSupplier =
bufferSupplier;
}
@
Override
public void
request(long
n) {
if (
Operators.
validate(
n)) {
s.
request(
Operators.
multiplyCap(
n,
size));
}
}
@
Override
public void
cancel() {
s.
cancel();
Operators.
onDiscardMultiple(
buffer, this.
ctx);
}
@
Override
public void
onSubscribe(
Subscription s) {
if (
Operators.
validate(this.
s,
s)) {
this.
s =
s;
actual.
onSubscribe(this);
}
}
@
Override
public void
onNext(T
t) {
if (
done) {
Operators.
onNextDropped(
t, this.
ctx);
return;
}
C
b =
buffer;
if (
b == null) {
try {
b =
Objects.
requireNonNull(
bufferSupplier.
get(),
"The bufferSupplier returned a null buffer");
}
catch (
Throwable e) {
onError(
Operators.
onOperatorError(
s,
e,
t, this.
ctx));
Operators.
onDiscard(
t, this.
ctx); //this is in no buffer
return;
}
buffer =
b;
}
b.
add(
t);
if (
b.
size() ==
size) {
buffer = null;
actual.
onNext(
b);
}
}
@
Override
public void
onError(
Throwable t) {
if (
done) {
Operators.
onErrorDropped(
t, this.
ctx);
return;
}
done = true;
actual.
onError(
t);
Operators.
onDiscardMultiple(
buffer, this.
ctx);
}
@
Override
public void
onComplete() {
if (
done) {
return;
}
done = true;
C
b =
buffer;
if (
b != null && !
b.
isEmpty()) {
actual.
onNext(
b);
}
actual.
onComplete();
}
@
Override
public
CoreSubscriber<? super C>
actual() {
return
actual;
}
@
Override
@
Nullable
public
Object scanUnsafe(
Attr key) {
if (
key ==
Attr.
PARENT) return
s;
if (
key ==
Attr.
TERMINATED) return
done;
if (
key ==
Attr.
BUFFERED) {
C
b =
buffer;
return
b != null ?
b.
size() : 0;
}
if (
key ==
Attr.
CAPACITY) return
size;
if (
key ==
Attr.
PREFETCH) return
size;
return
InnerOperator.super.scanUnsafe(
key);
}
}
static final class
BufferSkipSubscriber<T, C extends
Collection<? super T>>
implements
InnerOperator<T, C> {
final
CoreSubscriber<? super C>
actual;
final
Context ctx;
final
Supplier<C>
bufferSupplier;
final int
size;
final int
skip;
C
buffer;
Subscription s;
boolean
done;
long
index;
volatile int
wip;
@
SuppressWarnings("rawtypes")
static final
AtomicIntegerFieldUpdater<
BufferSkipSubscriber>
WIP =
AtomicIntegerFieldUpdater.
newUpdater(
BufferSkipSubscriber.class, "wip");
BufferSkipSubscriber(
CoreSubscriber<? super C>
actual,
int
size,
int
skip,
Supplier<C>
bufferSupplier) {
this.
actual =
actual;
this.
ctx =
actual.
currentContext();
this.
size =
size;
this.
skip =
skip;
this.
bufferSupplier =
bufferSupplier;
}
@
Override
public void
request(long
n) {
if (!
Operators.
validate(
n)) {
return;
}
if (
wip == 0 &&
WIP.
compareAndSet(this, 0, 1)) {
// n full buffers
long
u =
Operators.
multiplyCap(
n,
size);
// + (n - 1) gaps
long
v =
Operators.
multiplyCap(
skip -
size,
n - 1);
s.
request(
Operators.
addCap(
u,
v));
}
else {
// n full buffer + gap
s.
request(
Operators.
multiplyCap(
skip,
n));
}
}
@
Override
public void
cancel() {
s.
cancel();
Operators.
onDiscardMultiple(
buffer, this.
ctx);
}
@
Override
public void
onSubscribe(
Subscription s) {
if (
Operators.
validate(this.
s,
s)) {
this.
s =
s;
actual.
onSubscribe(this);
}
}
@
Override
public void
onNext(T
t) {
if (
done) {
Operators.
onNextDropped(
t, this.
ctx);
return;
}
C
b =
buffer;
long
i =
index;
if (
i %
skip == 0L) {
try {
b =
Objects.
requireNonNull(
bufferSupplier.
get(),
"The bufferSupplier returned a null buffer");
}
catch (
Throwable e) {
onError(
Operators.
onOperatorError(
s,
e,
t, this.
ctx));
Operators.
onDiscard(
t, this.
ctx); //t hasn't got a chance to end up in any buffer
return;
}
buffer =
b;
}
if (
b != null) {
b.
add(
t);
if (
b.
size() ==
size) {
buffer = null;
actual.
onNext(
b);
}
}
else {
//dropping
Operators.
onDiscard(
t, this.
ctx);
}
index =
i + 1;
}
@
Override
public void
onError(
Throwable t) {
if (
done) {
Operators.
onErrorDropped(
t, this.
ctx);
return;
}
done = true;
C
b =
buffer;
buffer = null;
actual.
onError(
t);
Operators.
onDiscardMultiple(
b, this.
ctx);
}
@
Override
public void
onComplete() {
if (
done) {
return;
}
done = true;
C
b =
buffer;
buffer = null;
if (
b != null) {
actual.
onNext(
b);
}
actual.
onComplete();
}
@
Override
public
CoreSubscriber<? super C>
actual() {
return
actual;
}
@
Override
@
Nullable
public
Object scanUnsafe(
Attr key) {
if (
key ==
Attr.
PARENT) return
s;
if (
key ==
Attr.
TERMINATED) return
done;
if (
key ==
Attr.
CAPACITY) return
size;
if (
key ==
Attr.
BUFFERED) {
C
b =
buffer;
return
b != null ?
b.
size() : 0;
}
if (
key ==
Attr.
PREFETCH) return
size;
return
InnerOperator.super.scanUnsafe(
key);
}
}
static final class
BufferOverlappingSubscriber<T, C extends
Collection<? super T>>
extends
ArrayDeque<C>
implements
BooleanSupplier,
InnerOperator<T, C> {
final
CoreSubscriber<? super C>
actual;
final
Context ctx;
final
Supplier<C>
bufferSupplier;
final int
size;
final int
skip;
Subscription s;
boolean
done;
long
index;
volatile boolean
cancelled;
long
produced;
volatile int
once;
@
SuppressWarnings("rawtypes")
static final
AtomicIntegerFieldUpdater<
BufferOverlappingSubscriber>
ONCE =
AtomicIntegerFieldUpdater.
newUpdater(
BufferOverlappingSubscriber.class,
"once");
volatile long
requested;
@
SuppressWarnings("rawtypes")
static final
AtomicLongFieldUpdater<
BufferOverlappingSubscriber>
REQUESTED =
AtomicLongFieldUpdater.
newUpdater(
BufferOverlappingSubscriber.class,
"requested");
BufferOverlappingSubscriber(
CoreSubscriber<? super C>
actual,
int
size,
int
skip,
Supplier<C>
bufferSupplier) {
this.
actual =
actual;
this.
ctx =
actual.
currentContext();
this.
size =
size;
this.
skip =
skip;
this.
bufferSupplier =
bufferSupplier;
}
@
Override
public boolean
getAsBoolean() {
return
cancelled;
}
@
Override
public void
request(long
n) {
if (!
Operators.
validate(
n)) {
return;
}
if (
DrainUtils.
postCompleteRequest(
n,
actual,
this,
REQUESTED,
this,
this)) {
return;
}
if (
once == 0 &&
ONCE.
compareAndSet(this, 0, 1)) {
// (n - 1) skips
long
u =
Operators.
multiplyCap(
skip,
n - 1);
// + 1 full buffer
long
r =
Operators.
addCap(
size,
u);
s.
request(
r);
}
else {
// n skips
long
r =
Operators.
multiplyCap(
skip,
n);
s.
request(
r);
}
}
@
Override
public void
cancel() {
cancelled = true;
s.
cancel();
clear();
}
@
Override
public void
onSubscribe(
Subscription s) {
if (
Operators.
validate(this.
s,
s)) {
this.
s =
s;
actual.
onSubscribe(this);
}
}
@
Override
public void
onNext(T
t) {
if (
done) {
Operators.
onNextDropped(
t, this.
ctx);
return;
}
long
i =
index;
if (
i %
skip == 0L) {
C
b;
try {
b =
Objects.
requireNonNull(
bufferSupplier.
get(),
"The bufferSupplier returned a null buffer");
}
catch (
Throwable e) {
onError(
Operators.
onOperatorError(
s,
e,
t, this.
ctx));
Operators.
onDiscard(
t, this.
ctx); //didn't get a chance to be added to a buffer
return;
}
offer(
b);
}
C
b =
peek();
if (
b != null &&
b.
size() + 1 ==
size) {
poll();
b.
add(
t);
actual.
onNext(
b);
produced++;
}
for (C
b0 : this) {
b0.
add(
t);
}
index =
i + 1;
}
@
Override
public void
onError(
Throwable t) {
if (
done) {
Operators.
onErrorDropped(
t, this.
ctx);
return;
}
done = true;
clear();
actual.
onError(
t);
}
@
Override
public void
clear() {
for(C
b: this) {
Operators.
onDiscardMultiple(
b, this.
ctx);
}
super.clear();
}
@
Override
public void
onComplete() {
if (
done) {
return;
}
done = true;
long
p =
produced;
if (
p != 0L) {
Operators.
produced(
REQUESTED,this,
p);
}
DrainUtils.
postComplete(
actual, this,
REQUESTED, this, 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.
TERMINATED) return
done;
if (
key ==
Attr.
CANCELLED) return
cancelled;
if (
key ==
Attr.
CAPACITY) return
size() *
size;
if (
key ==
Attr.
BUFFERED) return
stream().
mapToInt(
Collection::size).
sum();
if (
key ==
Attr.
PREFETCH) return
Integer.
MAX_VALUE;
if (
key ==
Attr.
REQUESTED_FROM_DOWNSTREAM) return
requested;
return
InnerOperator.super.scanUnsafe(
key);
}
}
}