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/*
* 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 io.netty.util.internal.shaded.org.jctools.queues;
import static io.netty.util.internal.shaded.org.jctools.util.UnsafeAccess.UNSAFE;
import static io.netty.util.internal.shaded.org.jctools.util.UnsafeAccess.fieldOffset;
import static io.netty.util.internal.shaded.org.jctools.util.UnsafeRefArrayAccess.*;
abstract class SpmcArrayQueueL1Pad extends ConcurrentCircularArrayQueue
{
long p01, p02, p03, p04, p05, p06, p07;
long p10, p11, p12, p13, p14, p15, p16, p17;
SpmcArrayQueueL1Pad(int capacity)
{
super(capacity);
}
}
//$gen:ordered-fields
abstract class SpmcArrayQueueProducerIndexField extends SpmcArrayQueueL1Pad
{
protected final static long P_INDEX_OFFSET = fieldOffset(SpmcArrayQueueProducerIndexField.class,"producerIndex");
private volatile long producerIndex;
SpmcArrayQueueProducerIndexField(int capacity)
{
super(capacity);
}
@Override
public final long lvProducerIndex()
{
return producerIndex;
}
final long lpProducerIndex()
{
return UNSAFE.getLong(this, P_INDEX_OFFSET);
}
final void soProducerIndex(long newValue)
{
UNSAFE.putOrderedLong(this, P_INDEX_OFFSET, newValue);
}
}
abstract class SpmcArrayQueueL2Pad extends SpmcArrayQueueProducerIndexField
{
long p01, p02, p03, p04, p05, p06, p07;
long p10, p11, p12, p13, p14, p15, p16, p17;
SpmcArrayQueueL2Pad(int capacity)
{
super(capacity);
}
}
//$gen:ordered-fields
abstract class SpmcArrayQueueConsumerIndexField extends SpmcArrayQueueL2Pad
{
protected final static long C_INDEX_OFFSET = fieldOffset(SpmcArrayQueueConsumerIndexField.class, "consumerIndex");
private volatile long consumerIndex;
SpmcArrayQueueConsumerIndexField(int capacity)
{
super(capacity);
}
@Override
public final long lvConsumerIndex()
{
return consumerIndex;
}
final boolean casConsumerIndex(long expect, long newValue)
{
return UNSAFE.compareAndSwapLong(this, C_INDEX_OFFSET, expect, newValue);
}
}
abstract class SpmcArrayQueueMidPad extends SpmcArrayQueueConsumerIndexField
{
long p01, p02, p03, p04, p05, p06, p07;
long p10, p11, p12, p13, p14, p15, p16, p17;
SpmcArrayQueueMidPad(int capacity)
{
super(capacity);
}
}
//$gen:ordered-fields
abstract class SpmcArrayQueueProducerIndexCacheField extends SpmcArrayQueueMidPad
{
// This is separated from the consumerIndex which will be highly contended in the hope that this value spends most
// of it's time in a cache line that is Shared(and rarely invalidated)
private volatile long producerIndexCache;
SpmcArrayQueueProducerIndexCacheField(int capacity)
{
super(capacity);
}
protected final long lvProducerIndexCache()
{
return producerIndexCache;
}
protected final void svProducerIndexCache(long newValue)
{
producerIndexCache = newValue;
}
}
abstract class SpmcArrayQueueL3Pad extends SpmcArrayQueueProducerIndexCacheField
{
long p01, p02, p03, p04, p05, p06, p07;
long p10, p11, p12, p13, p14, p15, p16, p17;
SpmcArrayQueueL3Pad(int capacity)
{
super(capacity);
}
}
public class SpmcArrayQueue extends SpmcArrayQueueL3Pad
{
public SpmcArrayQueue(final int capacity)
{
super(capacity);
}
@Override
public boolean offer(final E e)
{
if (null == e)
{
throw new NullPointerException();
}
final E[] buffer = this.buffer;
final long mask = this.mask;
final long currProducerIndex = lvProducerIndex();
final long offset = calcCircularRefElementOffset(currProducerIndex, mask);
if (null != lvRefElement(buffer, offset))
{
long size = currProducerIndex - lvConsumerIndex();
if (size > mask)
{
return false;
}
else
{
// spin wait for slot to clear, buggers wait freedom
while (null != lvRefElement(buffer, offset))
{
// BURN
}
}
}
soRefElement(buffer, offset, e);
// single producer, so store ordered is valid. It is also required to correctly publish the element
// and for the consumers to pick up the tail value.
soProducerIndex(currProducerIndex + 1);
return true;
}
@Override
public E poll()
{
long currentConsumerIndex;
long currProducerIndexCache = lvProducerIndexCache();
do
{
currentConsumerIndex = lvConsumerIndex();
if (currentConsumerIndex >= currProducerIndexCache)
{
long currProducerIndex = lvProducerIndex();
if (currentConsumerIndex >= currProducerIndex)
{
return null;
}
else
{
currProducerIndexCache = currProducerIndex;
svProducerIndexCache(currProducerIndex);
}
}
}
while (!casConsumerIndex(currentConsumerIndex, currentConsumerIndex + 1));
// consumers are gated on latest visible tail, and so can't see a null value in the queue or overtake
// and wrap to hit same location.
return removeElement(buffer, currentConsumerIndex, mask);
}
private E removeElement(final E[] buffer, long index, final long mask)
{
final long offset = calcCircularRefElementOffset(index, mask);
// load plain, element happens before it's index becomes visible
final E e = lpRefElement(buffer, offset);
// store ordered, make sure nulling out is visible. Producer is waiting for this value.
soRefElement(buffer, offset, null);
return e;
}
@Override
public E peek()
{
final long mask = this.mask;
final long currProducerIndexCache = lvProducerIndexCache();
long currentConsumerIndex;
E e;
do
{
currentConsumerIndex = lvConsumerIndex();
if (currentConsumerIndex >= currProducerIndexCache)
{
long currProducerIndex = lvProducerIndex();
if (currentConsumerIndex >= currProducerIndex)
{
return null;
}
else
{
svProducerIndexCache(currProducerIndex);
}
}
}
while (null == (e = lvRefElement(buffer,
calcCircularRefElementOffset(currentConsumerIndex, mask))));
return e;
}
@Override
public boolean relaxedOffer(E e)
{
if (null == e)
{
throw new NullPointerException("Null is not a valid element");
}
final E[] buffer = this.buffer;
final long mask = this.mask;
final long producerIndex = lpProducerIndex();
final long offset = calcCircularRefElementOffset(producerIndex, mask);
if (null != lvRefElement(buffer, offset))
{
return false;
}
soRefElement(buffer, offset, e);
// single producer, so store ordered is valid. It is also required to correctly publish the element
// and for the consumers to pick up the tail value.
soProducerIndex(producerIndex + 1);
return true;
}
@Override
public E relaxedPoll()
{
return poll();
}
@Override
public E relaxedPeek()
{
final E[] buffer = this.buffer;
final long mask = this.mask;
final long consumerIndex = lvConsumerIndex();
return lvRefElement(buffer, calcCircularRefElementOffset(consumerIndex, mask));
}
@Override
public int drain(final Consumer c, final int limit)
{
if (null == c)
throw new IllegalArgumentException("c is null");
if (limit < 0)
throw new IllegalArgumentException("limit is negative: " + limit);
if (limit == 0)
return 0;
final E[] buffer = this.buffer;
final long mask = this.mask;
long currProducerIndexCache = lvProducerIndexCache();
int adjustedLimit = 0;
long currentConsumerIndex;
do
{
currentConsumerIndex = lvConsumerIndex();
// is there any space in the queue?
if (currentConsumerIndex >= currProducerIndexCache)
{
long currProducerIndex = lvProducerIndex();
if (currentConsumerIndex >= currProducerIndex)
{
return 0;
}
else
{
currProducerIndexCache = currProducerIndex;
svProducerIndexCache(currProducerIndex);
}
}
// try and claim up to 'limit' elements in one go
int remaining = (int) (currProducerIndexCache - currentConsumerIndex);
adjustedLimit = Math.min(remaining, limit);
}
while (!casConsumerIndex(currentConsumerIndex, currentConsumerIndex + adjustedLimit));
for (int i = 0; i < adjustedLimit; i++)
{
c.accept(removeElement(buffer, currentConsumerIndex + i, mask));
}
return adjustedLimit;
}
@Override
public int fill(final Supplier s, final int limit)
{
if (null == s)
throw new IllegalArgumentException("supplier is null");
if (limit < 0)
throw new IllegalArgumentException("limit is negative:" + limit);
if (limit == 0)
return 0;
final E[] buffer = this.buffer;
final long mask = this.mask;
long producerIndex = this.lpProducerIndex();
for (int i = 0; i < limit; i++)
{
final long offset = calcCircularRefElementOffset(producerIndex, mask);
if (null != lvRefElement(buffer, offset))
{
return i;
}
producerIndex++;
soRefElement(buffer, offset, s.get());
soProducerIndex(producerIndex); // ordered store -> atomic and ordered for size()
}
return limit;
}
@Override
public int drain(final Consumer c)
{
return MessagePassingQueueUtil.drain(this, c);
}
@Override
public int fill(final Supplier s)
{
return fill(s, capacity());
}
@Override
public void drain(final Consumer c, final WaitStrategy w, final ExitCondition exit)
{
MessagePassingQueueUtil.drain(this, c, w, exit);
}
@Override
public void fill(final Supplier s, final WaitStrategy w, final ExitCondition e)
{
MessagePassingQueueUtil.fill(this, s, w, e);
}
}