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- /*
- * Javassist, a Java-bytecode translator toolkit.
- * Copyright (C) 1999-2003 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.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;
- }
- }
- 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));
- }
- }
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