/*
 * Copyright (c) 2012, 2025, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

import java.lang.classfile.ClassFile;
import java.lang.classfile.ClassTransform;
import java.lang.classfile.CodeBuilder;
import java.lang.classfile.CodeElement;
import java.lang.classfile.CodeTransform;

class Asmator {
    static byte[] fixup(byte[] buf) {
        return ClassFile.of().transformClass(ClassFile.of().parse(buf), ClassTransform.transformingMethodBodies(
                m -> m.methodName().equalsString("callme"),
                new CodeTransform() {
                    @Override
                    public void atStart(CodeBuilder builder) {
                        // make receiver go dead!
                        builder.aconst_null().astore(0);
                    }

                    @Override
                    public void accept(CodeBuilder builder, CodeElement element) {
                        builder.with(element); // pass through
                    }
                }
        ));
    }
}