/*
* Copyright 2012 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.
*/
package io.netty.buffer;
import io.netty.util.ResourceLeakDetector;
import io.netty.util.ResourceLeakTracker;
import io.netty.util.internal.PlatformDependent;
import io.netty.util.internal.StringUtil;
/**
* Skeletal {@link ByteBufAllocator} implementation to extend.
*/
public abstract class AbstractByteBufAllocator implements ByteBufAllocator {
static final int DEFAULT_INITIAL_CAPACITY = 256;
static final int DEFAULT_MAX_CAPACITY = Integer.MAX_VALUE;
static final int DEFAULT_MAX_COMPONENTS = 16;
static final int CALCULATE_THRESHOLD = 1048576 * 4; // 4 MiB page
protected static ByteBuf toLeakAwareBuffer(ByteBuf buf) {
ResourceLeakTracker<ByteBuf> leak;
switch (ResourceLeakDetector.getLevel()) {
case SIMPLE:
leak = AbstractByteBuf.leakDetector.track(buf);
if (leak != null) {
buf = new SimpleLeakAwareByteBuf(buf, leak);
}
break;
case ADVANCED:
case PARANOID:
leak = AbstractByteBuf.leakDetector.track(buf);
if (leak != null) {
buf = new AdvancedLeakAwareByteBuf(buf, leak);
}
break;
default:
break;
}
return buf;
}
protected static CompositeByteBuf toLeakAwareBuffer(CompositeByteBuf buf) {
ResourceLeakTracker<ByteBuf> leak;
switch (ResourceLeakDetector.getLevel()) {
case SIMPLE:
leak = AbstractByteBuf.leakDetector.track(buf);
if (leak != null) {
buf = new SimpleLeakAwareCompositeByteBuf(buf, leak);
}
break;
case ADVANCED:
case PARANOID:
leak = AbstractByteBuf.leakDetector.track(buf);
if (leak != null) {
buf = new AdvancedLeakAwareCompositeByteBuf(buf, leak);
}
break;
default:
break;
}
return buf;
}
private final boolean directByDefault;
private final ByteBuf emptyBuf;
/**
* Instance use heap buffers by default
*/
protected AbstractByteBufAllocator() {
this(false);
}
/**
* Create new instance
*
* @param preferDirect {@code true} if {@link #buffer(int)} should try to allocate a direct buffer rather than
* a heap buffer
*/
protected AbstractByteBufAllocator(boolean preferDirect) {
directByDefault = preferDirect && PlatformDependent.hasUnsafe();
emptyBuf = new EmptyByteBuf(this);
}
@Override
public ByteBuf buffer() {
if (directByDefault) {
return directBuffer();
}
return heapBuffer();
}
@Override
public ByteBuf buffer(int initialCapacity) {
if (directByDefault) {
return directBuffer(initialCapacity);
}
return heapBuffer(initialCapacity);
}
@Override
public ByteBuf buffer(int initialCapacity, int maxCapacity) {
if (directByDefault) {
return directBuffer(initialCapacity, maxCapacity);
}
return heapBuffer(initialCapacity, maxCapacity);
}
@Override
public ByteBuf ioBuffer() {
if (PlatformDependent.hasUnsafe()) {
return directBuffer(DEFAULT_INITIAL_CAPACITY);
}
return heapBuffer(DEFAULT_INITIAL_CAPACITY);
}
@Override
public ByteBuf ioBuffer(int initialCapacity) {
if (PlatformDependent.hasUnsafe()) {
return directBuffer(initialCapacity);
}
return heapBuffer(initialCapacity);
}
@Override
public ByteBuf ioBuffer(int initialCapacity, int maxCapacity) {
if (PlatformDependent.hasUnsafe()) {
return directBuffer(initialCapacity, maxCapacity);
}
return heapBuffer(initialCapacity, maxCapacity);
}
@Override
public ByteBuf heapBuffer() {
return heapBuffer(DEFAULT_INITIAL_CAPACITY, DEFAULT_MAX_CAPACITY);
}
@Override
public ByteBuf heapBuffer(int initialCapacity) {
return heapBuffer(initialCapacity, DEFAULT_MAX_CAPACITY);
}
@Override
public ByteBuf heapBuffer(int initialCapacity, int maxCapacity) {
if (initialCapacity == 0 && maxCapacity == 0) {
return emptyBuf;
}
validate(initialCapacity, maxCapacity);
return newHeapBuffer(initialCapacity, maxCapacity);
}
@Override
public ByteBuf directBuffer() {
return directBuffer(DEFAULT_INITIAL_CAPACITY, DEFAULT_MAX_CAPACITY);
}
@Override
public ByteBuf directBuffer(int initialCapacity) {
return directBuffer(initialCapacity, DEFAULT_MAX_CAPACITY);
}
@Override
public ByteBuf directBuffer(int initialCapacity, int maxCapacity) {
if (initialCapacity == 0 && maxCapacity == 0) {
return emptyBuf;
}
validate(initialCapacity, maxCapacity);
return newDirectBuffer(initialCapacity, maxCapacity);
}
@Override
public CompositeByteBuf compositeBuffer() {
if (directByDefault) {
return compositeDirectBuffer();
}
return compositeHeapBuffer();
}
@Override
public CompositeByteBuf compositeBuffer(int maxNumComponents) {
if (directByDefault) {
return compositeDirectBuffer(maxNumComponents);
}
return compositeHeapBuffer(maxNumComponents);
}
@Override
public CompositeByteBuf compositeHeapBuffer() {
return compositeHeapBuffer(DEFAULT_MAX_COMPONENTS);
}
@Override
public CompositeByteBuf compositeHeapBuffer(int maxNumComponents) {
return toLeakAwareBuffer(new CompositeByteBuf(this, false, maxNumComponents));
}
@Override
public CompositeByteBuf compositeDirectBuffer() {
return compositeDirectBuffer(DEFAULT_MAX_COMPONENTS);
}
@Override
public CompositeByteBuf compositeDirectBuffer(int maxNumComponents) {
return toLeakAwareBuffer(new CompositeByteBuf(this, true, maxNumComponents));
}
private static void validate(int initialCapacity, int maxCapacity) {
if (initialCapacity < 0) {
throw new IllegalArgumentException("initialCapacity: " + initialCapacity + " (expected: 0+)");
}
if (initialCapacity > maxCapacity) {
throw new IllegalArgumentException(String.format(
"initialCapacity: %d (expected: not greater than maxCapacity(%d)",
initialCapacity, maxCapacity));
}
}
/**
* Create a heap {@link ByteBuf} with the given initialCapacity and maxCapacity.
*/
protected abstract ByteBuf newHeapBuffer(int initialCapacity, int maxCapacity);
/**
* Create a direct {@link ByteBuf} with the given initialCapacity and maxCapacity.
*/
protected abstract ByteBuf newDirectBuffer(int initialCapacity, int maxCapacity);
@Override
public String toString() {
return StringUtil.simpleClassName(this) + "(directByDefault: " + directByDefault + ')';
}
@Override
public int calculateNewCapacity(int minNewCapacity, int maxCapacity) {
if (minNewCapacity < 0) {
throw new IllegalArgumentException("minNewCapacity: " + minNewCapacity + " (expected: 0+)");
}
if (minNewCapacity > maxCapacity) {
throw new IllegalArgumentException(String.format(
"minNewCapacity: %d (expected: not greater than maxCapacity(%d)",
minNewCapacity, maxCapacity));
}
final int threshold = CALCULATE_THRESHOLD; // 4 MiB page
if (minNewCapacity == threshold) {
return threshold;
}
// If over threshold, do not double but just increase by threshold.
if (minNewCapacity > threshold) {
int newCapacity = minNewCapacity / threshold * threshold;
if (newCapacity > maxCapacity - threshold) {
newCapacity = maxCapacity;
} else {
newCapacity += threshold;
}
return newCapacity;
}
// Not over threshold. Double up to 4 MiB, starting from 64.
int newCapacity = 64;
while (newCapacity < minNewCapacity) {
newCapacity <<= 1;
}
return Math.min(newCapacity, maxCapacity);
}
}