/*
* Hibernate, Relational Persistence for Idiomatic Java
*
* Copyright (c) 2008, Red Hat Middleware LLC or third-party contributors as
* indicated by the @author tags or express copyright attribution
* statements applied by the authors. All third-party contributions are
* distributed under license by Red Hat Middleware LLC.
*
* This copyrighted material is made available to anyone wishing to use, modify,
* copy, or redistribute it subject to the terms and conditions of the GNU
* Lesser General Public License, as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
* for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this distribution; if not, write to:
* Free Software Foundation, Inc.
* 51 Franklin Street, Fifth Floor
* Boston, MA 02110-1301 USA
*
*/
package org.hibernate.bytecode.cglib;
import java.security.ProtectionDomain;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.ByteArrayOutputStream;
import org.hibernate.repackage.cglib.transform.ClassTransformer;
import org.hibernate.repackage.cglib.transform.TransformingClassGenerator;
import org.hibernate.repackage.cglib.transform.ClassReaderGenerator;
import org.hibernate.repackage.cglib.transform.impl.InterceptFieldEnabled;
import org.hibernate.repackage.cglib.transform.impl.InterceptFieldFilter;
import org.hibernate.repackage.cglib.transform.impl.InterceptFieldTransformer;
import org.hibernate.repackage.cglib.core.ClassNameReader;
import org.hibernate.repackage.cglib.core.DebuggingClassWriter;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.hibernate.bytecode.AbstractClassTransformerImpl;
import org.hibernate.bytecode.util.FieldFilter;
import org.hibernate.bytecode.util.ClassFilter;
import org.hibernate.HibernateException;
import org.hibernate.repackage.cglib.asm.Attribute;
import org.hibernate.repackage.cglib.asm.Type;
import org.hibernate.repackage.cglib.asm.ClassReader;
import org.hibernate.repackage.cglib.asm.ClassWriter;
import org.hibernate.repackage.cglib.asm.attrs.Attributes;
/**
* Enhance the classes allowing them to implements InterceptFieldEnabled
* This interface is then used by Hibernate for some optimizations.
*
* @author Emmanuel Bernard
*/
public class CglibClassTransformer extends AbstractClassTransformerImpl {
private static Logger log = LoggerFactory.getLogger( CglibClassTransformer.class.getName() );
public CglibClassTransformer(ClassFilter classFilter, FieldFilter fieldFilter) {
super( classFilter, fieldFilter );
}
protected byte[] doTransform(
ClassLoader loader,
String className,
Class classBeingRedefined,
ProtectionDomain protectionDomain,
byte[] classfileBuffer) {
ClassReader reader;
try {
reader = new ClassReader( new ByteArrayInputStream( classfileBuffer ) );
}
catch (IOException e) {
log.error( "Unable to read class", e );
throw new HibernateException( "Unable to read class: " + e.getMessage() );
}
String[] names = ClassNameReader.getClassInfo( reader );
ClassWriter w = new DebuggingClassWriter( true );
ClassTransformer t = getClassTransformer( names );
if ( t != null ) {
if ( log.isDebugEnabled() ) {
log.debug( "Enhancing " + className );
}
ByteArrayOutputStream out;
byte[] result;
try {
reader = new ClassReader( new ByteArrayInputStream( classfileBuffer ) );
new TransformingClassGenerator(
new ClassReaderGenerator( reader, attributes(), skipDebug() ), t
).generateClass( w );
out = new ByteArrayOutputStream();
out.write( w.toByteArray() );
result = out.toByteArray();
out.close();
}
catch (Exception e) {
log.error( "Unable to transform class", e );
throw new HibernateException( "Unable to transform class: " + e.getMessage() );
}
return result;
}
return classfileBuffer;
}
private Attribute[] attributes() {
return Attributes.getDefaultAttributes();
}
private boolean skipDebug() {
return false;
}
private ClassTransformer getClassTransformer(final String[] classInfo) {
if ( isAlreadyInstrumented( classInfo ) ) {
return null;
}
return new InterceptFieldTransformer(
new InterceptFieldFilter() {
public boolean acceptRead(Type owner, String name) {
return fieldFilter.shouldTransformFieldAccess( classInfo[0], owner.getClassName(), name );
}
public boolean acceptWrite(Type owner, String name) {
return fieldFilter.shouldTransformFieldAccess( classInfo[0], owner.getClassName(), name );
}
}
);
}
private boolean isAlreadyInstrumented(String[] classInfo) {
for ( int i = 1; i < classInfo.length; i++ ) {
if ( InterceptFieldEnabled.class.getName().equals( classInfo[i] ) ) {
return true;
}
}
return false;
}
}