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VoltDB client interface libraries
/*
* Copyright 2014 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_voltpatches.util.internal;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.nio.ByteBuffer;
import io.netty_voltpatches.util.internal.logging.InternalLogger;
import io.netty_voltpatches.util.internal.logging.InternalLoggerFactory;
/**
* Allows to free direct {@link ByteBuffer} by using Cleaner. This is encapsulated in an extra class to be able
* to use {@link PlatformDependent0} on Android without problems.
*
* For more details see #2604.
*/
final class Cleaner0 {
private static final long CLEANER_FIELD_OFFSET;
private static final Method CLEAN_METHOD;
private static final boolean CLEANER_IS_RUNNABLE;
private static final InternalLogger logger = InternalLoggerFactory.getInstance(Cleaner0.class);
static {
ByteBuffer direct = ByteBuffer.allocateDirect(1);
Field cleanerField;
long fieldOffset = -1;
Method clean = null;
boolean cleanerIsRunnable = false;
if (PlatformDependent0.hasUnsafe()) {
try {
cleanerField = direct.getClass().getDeclaredField("cleaner");
cleanerField.setAccessible(true);
fieldOffset = PlatformDependent0.objectFieldOffset(cleanerField);
Object cleaner = cleanerField.get(direct);
try {
// Cleaner implements Runnable from JDK9 onwards.
Runnable runnable = (Runnable) cleaner;
runnable.run();
cleanerIsRunnable = true;
} catch (ClassCastException ignored) {
clean = cleaner.getClass().getDeclaredMethod("clean");
clean.invoke(cleaner);
}
} catch (Throwable t) {
// We don't have ByteBuffer.cleaner().
fieldOffset = -1;
clean = null;
cleanerIsRunnable = false;
}
}
logger.debug("java.nio.ByteBuffer.cleaner(): {}", fieldOffset != -1? "available" : "unavailable");
CLEANER_FIELD_OFFSET = fieldOffset;
CLEAN_METHOD = clean;
CLEANER_IS_RUNNABLE = cleanerIsRunnable;
// free buffer if possible
freeDirectBuffer(direct);
}
static void freeDirectBuffer(ByteBuffer buffer) {
if (CLEANER_FIELD_OFFSET == -1 || !buffer.isDirect()) {
return;
}
assert CLEAN_METHOD != null || CLEANER_IS_RUNNABLE:
"CLEANER_FIELD_OFFSET != -1 implies CLEAN_METHOD != null or CLEANER_IS_RUNNABLE == true";
try {
Object cleaner = PlatformDependent0.getObject(buffer, CLEANER_FIELD_OFFSET);
if (cleaner != null) {
if (CLEANER_IS_RUNNABLE) {
((Runnable) cleaner).run();
} else {
CLEAN_METHOD.invoke(cleaner);
}
}
} catch (Throwable t) {
// Nothing we can do here.
}
}
private Cleaner0() { }
}