scouter.javassist.convert.TransformWriteField 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.CtClass;
import scouter.javassist.CtField;
import scouter.javassist.bytecode.BadBytecode;
import scouter.javassist.bytecode.CodeAttribute;
import scouter.javassist.bytecode.CodeIterator;
import scouter.javassist.bytecode.ConstPool;
final public class TransformWriteField extends TransformReadField {
public TransformWriteField(Transformer next, CtField field,
String methodClassname, String methodName)
{
super(next, field, methodClassname, methodName);
}
@Override
public int transform(CtClass tclazz, int pos, CodeIterator iterator,
ConstPool cp) throws BadBytecode
{
int c = iterator.byteAt(pos);
if (c == PUTFIELD || c == PUTSTATIC) {
int index = iterator.u16bitAt(pos + 1);
String typedesc = isField(tclazz.getClassPool(), cp,
fieldClass, fieldname, isPrivate, index);
if (typedesc != null) {
if (c == PUTSTATIC) {
CodeAttribute ca = iterator.get();
iterator.move(pos);
char c0 = typedesc.charAt(0);
if (c0 == 'J' || c0 == 'D') { // long or double
// insertGap() may insert 4 bytes.
pos = iterator.insertGap(3);
iterator.writeByte(ACONST_NULL, pos);
iterator.writeByte(DUP_X2, pos + 1);
iterator.writeByte(POP, pos + 2);
ca.setMaxStack(ca.getMaxStack() + 2);
}
else {
// insertGap() may insert 4 bytes.
pos = iterator.insertGap(2);
iterator.writeByte(ACONST_NULL, pos);
iterator.writeByte(SWAP, pos + 1);
ca.setMaxStack(ca.getMaxStack() + 1);
}
pos = iterator.next();
}
int mi = cp.addClassInfo(methodClassname);
String type = "(Ljava/lang/Object;" + typedesc + ")V";
int methodref = cp.addMethodrefInfo(mi, methodName, type);
iterator.writeByte(INVOKESTATIC, pos);
iterator.write16bit(methodref, pos + 1);
}
}
return pos;
}
}