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/*
* Javassist, a Java-bytecode translator toolkit.
* Copyright (C) 1999-2007 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.
*
* 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 javassist.convert;
import javassist.CtClass;
import javassist.CtMethod;
import javassist.ClassPool;
import javassist.Modifier;
import javassist.NotFoundException;
import javassist.bytecode.*;
public class TransformCall extends Transformer {
protected String classname, methodname, methodDescriptor;
protected String newClassname, newMethodname;
protected boolean newMethodIsPrivate;
/* cache */
protected int newIndex;
protected ConstPool constPool;
public TransformCall(Transformer next, CtMethod origMethod,
CtMethod substMethod)
{
this(next, origMethod.getName(), substMethod);
classname = origMethod.getDeclaringClass().getName();
}
public TransformCall(Transformer next, String oldMethodName,
CtMethod substMethod)
{
super(next);
methodname = oldMethodName;
methodDescriptor = substMethod.getMethodInfo2().getDescriptor();
classname = newClassname = substMethod.getDeclaringClass().getName();
newMethodname = substMethod.getName();
constPool = null;
newMethodIsPrivate = Modifier.isPrivate(substMethod.getModifiers());
}
public void initialize(ConstPool cp, CodeAttribute attr) {
if (constPool != cp)
newIndex = 0;
}
/**
* Modify INVOKEINTERFACE, INVOKESPECIAL, INVOKESTATIC and INVOKEVIRTUAL
* so that a different method is invoked. The class name in the operand
* of these instructions might be a subclass of the target class specified
* by <code>classname</code>. This method transforms the instruction
* in that case unless the subclass overrides the target method.
*/
public int transform(CtClass clazz, int pos, CodeIterator iterator,
ConstPool cp) throws BadBytecode
{
int c = iterator.byteAt(pos);
if (c == INVOKEINTERFACE || c == INVOKESPECIAL
|| c == INVOKESTATIC || c == INVOKEVIRTUAL) {
int index = iterator.u16bitAt(pos + 1);
String cname = cp.eqMember(methodname, methodDescriptor, index);
if (cname != null && matchClass(cname, clazz.getClassPool())) {
int ntinfo = cp.getMemberNameAndType(index);
pos = match(c, pos, iterator,
cp.getNameAndTypeDescriptor(ntinfo), cp);
}
}
return pos;
}
private boolean matchClass(String name, ClassPool pool) {
if (classname.equals(name))
return true;
try {
CtClass clazz = pool.get(name);
CtClass declClazz = pool.get(classname);
if (clazz.subtypeOf(declClazz))
try {
CtMethod m = clazz.getMethod(methodname, methodDescriptor);
return m.getDeclaringClass().getName().equals(classname);
}
catch (NotFoundException e) {
// maybe the original method has been removed.
return true;
}
}
catch (NotFoundException e) {
return false;
}
return false;
}
protected int match(int c, int pos, CodeIterator iterator,
int typedesc, ConstPool cp) throws BadBytecode
{
if (newIndex == 0) {
int nt = cp.addNameAndTypeInfo(cp.addUtf8Info(newMethodname),
typedesc);
int ci = cp.addClassInfo(newClassname);
if (c == INVOKEINTERFACE)
newIndex = cp.addInterfaceMethodrefInfo(ci, nt);
else {
if (newMethodIsPrivate && c == INVOKEVIRTUAL)
iterator.writeByte(INVOKESPECIAL, pos);
newIndex = cp.addMethodrefInfo(ci, nt);
}
constPool = cp;
}
iterator.write16bit(newIndex, pos + 1);
return pos;
}
}
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