/*
* 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 javassist.convert;
import javassist.bytecode.*;
import javassist.
CtClass;
import javassist.
CannotCompileException;
final public class
TransformNew extends
Transformer {
private int
nested;
private
String classname,
trapClass,
trapMethod;
public
TransformNew(
Transformer next,
String classname,
String trapClass,
String trapMethod) {
super(
next);
this.
classname =
classname;
this.
trapClass =
trapClass;
this.
trapMethod =
trapMethod;
}
public void
initialize(
ConstPool cp,
CodeAttribute attr) {
nested = 0;
}
/**
* Replace a sequence of
* NEW classname
* DUP
* ...
* INVOKESPECIAL
* with
* NOP
* NOP
* ...
* INVOKESTATIC trapMethod in trapClass
*/
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");
iterator.
writeByte(
NOP,
pos);
iterator.
writeByte(
NOP,
pos + 1);
iterator.
writeByte(
NOP,
pos + 2);
iterator.
writeByte(
NOP,
pos + 3);
++
nested;
StackMapTable smt
= (
StackMapTable)
iterator.
get().
getAttribute(
StackMapTable.
tag);
if (
smt != null)
smt.
removeNew(
pos);
StackMap sm
= (
StackMap)
iterator.
get().
getAttribute(
StackMap.
tag);
if (
sm != null)
sm.
removeNew(
pos);
}
}
else if (
c ==
INVOKESPECIAL) {
index =
iterator.
u16bitAt(
pos + 1);
int
typedesc =
cp.
isConstructor(
classname,
index);
if (
typedesc != 0 &&
nested > 0) {
int
methodref =
computeMethodref(
typedesc,
cp);
iterator.
writeByte(
INVOKESTATIC,
pos);
iterator.
write16bit(
methodref,
pos + 1);
--
nested;
}
}
return
pos;
}
private int
computeMethodref(int
typedesc,
ConstPool cp) {
int
classIndex =
cp.
addClassInfo(
trapClass);
int
mnameIndex =
cp.
addUtf8Info(
trapMethod);
typedesc =
cp.
addUtf8Info(
Descriptor.
changeReturnType(
classname,
cp.
getUtf8Info(
typedesc)));
return
cp.
addMethodrefInfo(
classIndex,
cp.
addNameAndTypeInfo(
mnameIndex,
typedesc));
}
}