scouter.javassist.convert.TransformNewClass Maven / Gradle / Ivy
/*
* Javassist, a Java-bytecode translator toolkit.
* Copyright (C) 1999- Shigeru Chiba. All Rights Reserved.
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. Alternatively, the contents of this file may be used under
* the terms of the GNU Lesser General Public License Version 2.1 or later,
* or the Apache License Version 2.0.
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*/
package scouter.javassist.convert;
import scouter.javassist.CannotCompileException;
import scouter.javassist.CtClass;
import scouter.javassist.bytecode.CodeAttribute;
import scouter.javassist.bytecode.CodeIterator;
import scouter.javassist.bytecode.ConstPool;
final public class TransformNewClass extends Transformer {
private int nested;
private String classname, newClassName;
private int newClassIndex, newMethodNTIndex, newMethodIndex;
public TransformNewClass(Transformer next,
String classname, String newClassName) {
super(next);
this.classname = classname;
this.newClassName = newClassName;
}
@Override
public void initialize(ConstPool cp, CodeAttribute attr) {
nested = 0;
newClassIndex = newMethodNTIndex = newMethodIndex = 0;
}
/**
* Modifies a sequence of
* NEW classname
* DUP
* ...
* INVOKESPECIAL classname:method
*/
@Override
public int transform(CtClass clazz, int pos, CodeIterator iterator,
ConstPool cp) throws CannotCompileException
{
int index;
int c = iterator.byteAt(pos);
if (c == NEW) {
index = iterator.u16bitAt(pos + 1);
if (cp.getClassInfo(index).equals(classname)) {
if (iterator.byteAt(pos + 3) != DUP)
throw new CannotCompileException(
"NEW followed by no DUP was found");
if (newClassIndex == 0)
newClassIndex = cp.addClassInfo(newClassName);
iterator.write16bit(newClassIndex, pos + 1);
++nested;
}
}
else if (c == INVOKESPECIAL) {
index = iterator.u16bitAt(pos + 1);
int typedesc = cp.isConstructor(classname, index);
if (typedesc != 0 && nested > 0) {
int nt = cp.getMethodrefNameAndType(index);
if (newMethodNTIndex != nt) {
newMethodNTIndex = nt;
newMethodIndex = cp.addMethodrefInfo(newClassIndex, nt);
}
iterator.write16bit(newMethodIndex, pos + 1);
--nested;
}
}
return pos;
}
}