159 lines
5.3 KiB
Java
159 lines
5.3 KiB
Java
/*
|
|
* Copyright 2016 The Netty Project
|
|
*
|
|
* The Netty Project licenses this file to you 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.
|
|
*/
|
|
/*
|
|
* 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;
|
|
|
|
import java.util.AbstractQueue;
|
|
import java.util.Iterator;
|
|
|
|
/**
|
|
* Forked from <a href="https://github.com/JCTools/JCTools">JCTools</a>.
|
|
*
|
|
* A base data structure for concurrent linked queues.
|
|
*
|
|
* @param <E>
|
|
*/
|
|
abstract class BaseLinkedQueue<E> extends BaseLinkedQueueConsumerNodeRef<E> {
|
|
long p01, p02, p03, p04, p05, p06, p07;
|
|
long p10, p11, p12, p13, p14, p15, p16, p17;
|
|
|
|
@Override
|
|
public final Iterator<E> iterator() {
|
|
throw new UnsupportedOperationException();
|
|
}
|
|
|
|
/**
|
|
* {@inheritDoc} <br>
|
|
* <p>
|
|
* IMPLEMENTATION NOTES:<br>
|
|
* This is an O(n) operation as we run through all the nodes and count them.<br>
|
|
*
|
|
* @see java.util.Queue#size()
|
|
*/
|
|
@Override
|
|
public final int size() {
|
|
// Read consumer first, this is important because if the producer is node is 'older' than the consumer the
|
|
// consumer may overtake it (consume past it). This will lead to an infinite loop below.
|
|
LinkedQueueNode<E> chaserNode = lvConsumerNode();
|
|
final LinkedQueueNode<E> producerNode = lvProducerNode();
|
|
int size = 0;
|
|
// must chase the nodes all the way to the producer node, but there's no need to chase a moving target.
|
|
while (chaserNode != producerNode && size < Integer.MAX_VALUE) {
|
|
LinkedQueueNode<E> next;
|
|
while ((next = chaserNode.lvNext()) == null) {
|
|
continue;
|
|
}
|
|
chaserNode = next;
|
|
size++;
|
|
}
|
|
return size;
|
|
}
|
|
|
|
/**
|
|
* {@inheritDoc} <br>
|
|
* <p>
|
|
* IMPLEMENTATION NOTES:<br>
|
|
* Queue is empty when producerNode is the same as consumerNode. An alternative implementation would be to observe
|
|
* the producerNode.value is null, which also means an empty queue because only the consumerNode.value is allowed to
|
|
* be null.
|
|
*
|
|
* @see MessagePassingQueue#isEmpty()
|
|
*/
|
|
@Override
|
|
public final boolean isEmpty() {
|
|
return lvConsumerNode() == lvProducerNode();
|
|
}
|
|
|
|
@Override
|
|
public int capacity() {
|
|
return UNBOUNDED_CAPACITY;
|
|
}
|
|
}
|
|
|
|
abstract class BaseLinkedQueuePad0<E> extends AbstractQueue<E> implements MessagePassingQueue<E> {
|
|
long p00, p01, p02, p03, p04, p05, p06, p07;
|
|
long p10, p11, p12, p13, p14, p15, p16;
|
|
}
|
|
|
|
abstract class BaseLinkedQueueProducerNodeRef<E> extends BaseLinkedQueuePad0<E> {
|
|
protected static final long P_NODE_OFFSET;
|
|
|
|
static {
|
|
try {
|
|
P_NODE_OFFSET = PlatformDependent0.objectFieldOffset(
|
|
BaseLinkedQueueProducerNodeRef.class.getDeclaredField("producerNode"));
|
|
} catch (NoSuchFieldException e) {
|
|
throw new RuntimeException(e);
|
|
}
|
|
}
|
|
protected LinkedQueueNode<E> producerNode;
|
|
protected final void spProducerNode(LinkedQueueNode<E> node) {
|
|
producerNode = node;
|
|
}
|
|
|
|
@SuppressWarnings("unchecked")
|
|
protected final LinkedQueueNode<E> lvProducerNode() {
|
|
return (LinkedQueueNode<E>) PlatformDependent0.getObjectVolatile(this, P_NODE_OFFSET);
|
|
}
|
|
|
|
protected final LinkedQueueNode<E> lpProducerNode() {
|
|
return producerNode;
|
|
}
|
|
}
|
|
|
|
abstract class BaseLinkedQueuePad1<E> extends BaseLinkedQueueProducerNodeRef<E> {
|
|
long p01, p02, p03, p04, p05, p06, p07;
|
|
long p10, p11, p12, p13, p14, p15, p16, p17;
|
|
}
|
|
|
|
abstract class BaseLinkedQueueConsumerNodeRef<E> extends BaseLinkedQueuePad1<E> {
|
|
protected static final long C_NODE_OFFSET;
|
|
|
|
static {
|
|
try {
|
|
C_NODE_OFFSET = PlatformDependent0.objectFieldOffset(
|
|
BaseLinkedQueueConsumerNodeRef.class.getDeclaredField("consumerNode"));
|
|
} catch (NoSuchFieldException e) {
|
|
throw new RuntimeException(e);
|
|
}
|
|
}
|
|
protected LinkedQueueNode<E> consumerNode;
|
|
protected final void spConsumerNode(LinkedQueueNode<E> node) {
|
|
consumerNode = node;
|
|
}
|
|
|
|
@SuppressWarnings("unchecked")
|
|
protected final LinkedQueueNode<E> lvConsumerNode() {
|
|
return (LinkedQueueNode<E>) PlatformDependent0.getObjectVolatile(this, C_NODE_OFFSET);
|
|
}
|
|
|
|
protected final LinkedQueueNode<E> lpConsumerNode() {
|
|
return consumerNode;
|
|
}
|
|
}
|