TestClassAdapter.java

/*
 * Copyright (c) 2010, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code 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 General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 *
 */
package org.hotswap.agent.plugin.proxy;

import java.util.Map;

import org.objectweb.asm.AnnotationVisitor;
import org.objectweb.asm.Attribute;
import org.objectweb.asm.ByteVector;
import org.objectweb.asm.ClassVisitor;
import org.objectweb.asm.ClassWriter;
import org.objectweb.asm.MethodVisitor;
import org.objectweb.asm.Type;
import org.objectweb.asm.commons.Remapper;
import org.objectweb.asm.commons.RemappingAnnotationAdapter;
import org.objectweb.asm.commons.RemappingClassAdapter;
import org.objectweb.asm.commons.RemappingMethodAdapter;

/**
 * @author Ivan Dubrov
 */
public class TestClassAdapter extends RemappingClassAdapter {
	/**
	 * This suffix is automatically removed from the method.
	 */
	private final static String METHOD_SUFFIX = "___";
	
	private boolean isObject;
	
	public TestClassAdapter(ClassVisitor cv, final Map<String, String> typeMappings) {
		super(cv, new Remapper() {
			@Override
			public String map(String type) {
				return typeMappings.containsKey(type) ? typeMappings.get(type) : type;
			}
		});
	}
	
	@Override
	public void visit(int version, int access, String name, String signature, String superName, String[] interfaces) {
		// For java/lang/Object redefinition
		String newName = remapper.mapType(name);
		if (newName.equals("java/lang/Object")) {
			superName = null;
			isObject = true;
		}
		super.visit(version, access, name, signature, superName, interfaces);
	}
	
	@Override
	public MethodVisitor visitMethod(int access, String name, String desc, String signature, String[] exceptions) {
		return super.visitMethod(access, stripMethodSuffix(name), desc, signature, exceptions);
	}
	
	/**
	 * Get renamed class name.
	 * 
	 * @return
	 */
	public String getClassName() {
		return remapper.mapType(className);
	}
	
	protected MethodVisitor createRemappingMethodAdapter(int access, String newDesc, MethodVisitor mv) {
		return new RemappingMethodAdapter(access, newDesc, mv, remapper) {
			@Override
			public void visitMethodInsn(int opcode, String owner, String name, String desc, boolean itf) {
				if (name.equals("<init>") && isObject && owner.equals("java/lang/Object")) {
					return;
				}
				
				super.visitMethodInsn(opcode, owner, stripMethodSuffix(name), desc, itf);
			}
		};
	}
	
	private static String stripMethodSuffix(String name) {
		int pos = name.indexOf(METHOD_SUFFIX);
		return (pos != -1) ? name.substring(0, pos) : name;
	}
	
	@Override
	public AnnotationVisitor visitAnnotation(final String desc, final boolean visible) {
		AnnotationVisitor av = super.visitAnnotation(remapper.mapDesc(desc), visible);
		return av == null ? null : new RemappingAnnotationAdapter(av, remapper) {
			@Override
			public void visitEnum(String name, String enumDesc, String value) {
				if (Type.getType(enumDesc).getClassName().equals(RedefinitionPolicy.class.getName())) {
					RedefinitionPolicy valueAsEnum = RedefinitionPolicy.valueOf(value);
					if (Type.getType(desc).getClassName().equals(FieldRedefinitionPolicy.class.getName())) {
						cv.visitAttribute(new SingleByteAttribute(FieldRedefinitionPolicy.class.getSimpleName(),
								(byte) valueAsEnum.ordinal()));
					}
					if (Type.getType(desc).getClassName().equals(MethodRedefinitionPolicy.class.getName())) {
						cv.visitAttribute(new SingleByteAttribute(MethodRedefinitionPolicy.class.getSimpleName(),
								(byte) valueAsEnum.ordinal()));
					}
				}
				super.visitEnum(name, desc, value);
			}
		};
	}
	
	private static class SingleByteAttribute extends Attribute {
		private byte value;
		
		public SingleByteAttribute(String name, byte value) {
			super(name);
			this.value = value;
		}
		
		@Override
		protected ByteVector write(ClassWriter writer, byte[] code, int len, int maxStack, int maxLocals) {
			return new ByteVector().putByte(value);
		}
	}
	
}