io.undertow.server.DirectByteBufferDeallocator Maven / Gradle / Ivy
Go to download
This artifact provides a single jar that contains all classes required to use remote EJB and JMS, including
all dependencies. It is intended for use by those not using maven, maven users should just import the EJB and
JMS BOM's instead (shaded JAR's cause lots of problems with maven, as it is very easy to inadvertently end up
with different versions on classes on the class path).
package io.undertow.server;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.nio.ByteBuffer;
import java.security.AccessController;
import java.security.PrivilegedAction;
import io.undertow.UndertowLogger;
import sun.misc.Unsafe;
/**
* {@link DirectByteBufferDeallocator} Utility class used to free direct buffer memory.
*/
public final class DirectByteBufferDeallocator {
private static final boolean SUPPORTED;
private static final Method cleaner;
private static final Method cleanerClean;
private static final Unsafe UNSAFE;
static {
String versionString = System.getProperty("java.specification.version");
if(versionString.equals("0.9")) {
//android hardcoded
versionString = "11";
} else if(versionString.startsWith("1.")) {
versionString = versionString.substring(2);
}
int version = Integer.parseInt(versionString);
Method tmpCleaner = null;
Method tmpCleanerClean = null;
boolean supported;
Unsafe tmpUnsafe = null;
if (version < 9) {
try {
tmpCleaner = getAccesibleMethod("java.nio.DirectByteBuffer", "cleaner");
tmpCleanerClean = getAccesibleMethod("sun.misc.Cleaner", "clean");
supported = true;
} catch (Throwable t) {
UndertowLogger.ROOT_LOGGER.directBufferDeallocatorInitializationFailed(t);
supported = false;
}
} else {
try {
tmpUnsafe = getUnsafe();
tmpCleanerClean = getDeclaredMethod(tmpUnsafe, "invokeCleaner", ByteBuffer.class);
supported = true;
} catch (Throwable t) {
UndertowLogger.ROOT_LOGGER.directBufferDeallocatorInitializationFailed(t);
supported = false;
}
}
SUPPORTED = supported;
cleaner = tmpCleaner;
cleanerClean = tmpCleanerClean;
UNSAFE = tmpUnsafe;
}
private DirectByteBufferDeallocator() {
// Utility Class
}
/**
* Attempts to deallocate the underlying direct memory.
* This is a no-op for buffers where {@link ByteBuffer#isDirect()} returns false.
*
* @param buffer to deallocate
*/
public static void free(ByteBuffer buffer) {
if (SUPPORTED && buffer != null && buffer.isDirect()) {
try {
if (UNSAFE != null) {
//use the JDK9 method
cleanerClean.invoke(UNSAFE, buffer);
} else {
Object cleaner = DirectByteBufferDeallocator.cleaner.invoke(buffer);
cleanerClean.invoke(cleaner);
}
} catch (Throwable t) {
UndertowLogger.ROOT_LOGGER.directBufferDeallocationFailed(t);
}
}
}
private static Unsafe getUnsafe() {
if (System.getSecurityManager() != null) {
return AccessController.doPrivileged(new PrivilegedAction() {
public Unsafe run() {
return getUnsafe0();
}
});
}
return getUnsafe0();
}
private static Unsafe getUnsafe0() {
try {
Field theUnsafe = Unsafe.class.getDeclaredField("theUnsafe");
theUnsafe.setAccessible(true);
return (Unsafe) theUnsafe.get(null);
} catch (Throwable t) {
throw new RuntimeException("JDK did not allow accessing unsafe", t);
}
}
private static Method getAccesibleMethod(String className, String methodName) {
if (System.getSecurityManager() != null) {
return AccessController.doPrivileged(new PrivilegedAction() {
@Override
public Method run() {
return getAccesibleMethod0(className, methodName);
}
});
}
return getAccesibleMethod0(className, methodName);
}
private static Method getAccesibleMethod0(String className, String methodName) {
try {
Method method = Class.forName(className).getMethod(methodName);
method.setAccessible(true);
return method;
} catch (Throwable t) {
throw new RuntimeException("JDK did not allow accessing method", t);
}
}
private static Method getDeclaredMethod(Unsafe tmpUnsafe, String methodName, Class... parameterTypes) {
if (System.getSecurityManager() != null) {
return AccessController.doPrivileged(new PrivilegedAction() {
@Override
public Method run() {
return getDeclaredMethod0(tmpUnsafe, methodName, parameterTypes);
}
});
}
return getDeclaredMethod0(tmpUnsafe, methodName, parameterTypes);
}
private static Method getDeclaredMethod0(Unsafe tmpUnsafe, String methodName, Class... parameterTypes) {
try {
Method method = tmpUnsafe.getClass().getDeclaredMethod(methodName, parameterTypes);
method.setAccessible(true);
return method;
} catch (Throwable t) {
throw new RuntimeException("JDK did not allow accessing method", t);
}
}
}