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Easy Redis Java client and Real-Time Data Platform. Valkey compatible. Sync/Async/RxJava3/Reactive API. Client side caching. Over 50 Redis based Java objects and services: JCache API, Apache Tomcat, Hibernate, Spring, Set, Multimap, SortedSet, Map, List, Queue, Deque, Semaphore, Lock, AtomicLong, Map Reduce, Bloom filter, Scheduler, RPC
/*
* Copyright 2013 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:
*
* https://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.buffer;
import java.util.concurrent.atomic.AtomicIntegerFieldUpdater;
import io.netty.util.internal.ReferenceCountUpdater;
/**
* Abstract base class for {@link ByteBuf} implementations that count references.
*/
public abstract class AbstractReferenceCountedByteBuf extends AbstractByteBuf {
private static final long REFCNT_FIELD_OFFSET =
ReferenceCountUpdater.getUnsafeOffset(AbstractReferenceCountedByteBuf.class, "refCnt");
private static final AtomicIntegerFieldUpdater AIF_UPDATER =
AtomicIntegerFieldUpdater.newUpdater(AbstractReferenceCountedByteBuf.class, "refCnt");
private static final ReferenceCountUpdater updater =
new ReferenceCountUpdater() {
@Override
protected AtomicIntegerFieldUpdater updater() {
return AIF_UPDATER;
}
@Override
protected long unsafeOffset() {
return REFCNT_FIELD_OFFSET;
}
};
// Value might not equal "real" reference count, all access should be via the updater
@SuppressWarnings({"unused", "FieldMayBeFinal"})
private volatile int refCnt;
protected AbstractReferenceCountedByteBuf(int maxCapacity) {
super(maxCapacity);
updater.setInitialValue(this);
}
@Override
boolean isAccessible() {
// Try to do non-volatile read for performance as the ensureAccessible() is racy anyway and only provide
// a best-effort guard.
return updater.isLiveNonVolatile(this);
}
@Override
public int refCnt() {
return updater.refCnt(this);
}
/**
* An unsafe operation intended for use by a subclass that sets the reference count of the buffer directly
*/
protected final void setRefCnt(int refCnt) {
updater.setRefCnt(this, refCnt);
}
/**
* An unsafe operation intended for use by a subclass that resets the reference count of the buffer to 1
*/
protected final void resetRefCnt() {
updater.resetRefCnt(this);
}
@Override
public ByteBuf retain() {
return updater.retain(this);
}
@Override
public ByteBuf retain(int increment) {
return updater.retain(this, increment);
}
@Override
public ByteBuf touch() {
return this;
}
@Override
public ByteBuf touch(Object hint) {
return this;
}
@Override
public boolean release() {
return handleRelease(updater.release(this));
}
@Override
public boolean release(int decrement) {
return handleRelease(updater.release(this, decrement));
}
private boolean handleRelease(boolean result) {
if (result) {
deallocate();
}
return result;
}
/**
* Called once {@link #refCnt()} is equals 0.
*/
protected abstract void deallocate();
}
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