third_party/ijar/test/GenDuplicatedUnsupportedAttribute.java

// Copyright 2024 The Bazel Authors. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//    http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package test;

import java.io.FileOutputStream;
import java.io.IOException;
import java.util.jar.JarOutputStream;
import java.util.zip.ZipEntry;
import org.objectweb.asm.Attribute;
import org.objectweb.asm.ByteVector;
import org.objectweb.asm.ClassWriter;
import org.objectweb.asm.MethodVisitor;
import org.objectweb.asm.Opcodes;

public class GenDuplicatedUnsupportedAttribute {
  public static void main(String[] args) throws IOException {
    try (JarOutputStream jos = new JarOutputStream(new FileOutputStream(args[0]))) {
      jos.putNextEntry(new ZipEntry("unsupportedattributes/Test1.class"));
      jos.write(dump("Test1"));
      jos.putNextEntry(new ZipEntry("unsupportedattributes/Test2.class"));
      jos.write(dump("Test2"));
    }
  }

  public static byte[] dump(String name) {
    ClassWriter cw = new ClassWriter(0);
    MethodVisitor mv;

    cw.visit(
        52,
        Opcodes.ACC_PUBLIC + Opcodes.ACC_SUPER,
        "unsupportedattributes/" + name,
        null,
        "java/lang/Object",
        null);

    // This is the important part for the test - repeat an unsupported attribute.
    cw.visitAttribute(
        new Attribute("some_unknown_type") {
          @Override
          protected ByteVector write(
              ClassWriter classWriter, byte[] code, int codeLength, int maxStack, int maxLocals) {
            return new ByteVector().putInt(1234);
          }
        });

    {
      mv = cw.visitMethod(Opcodes.ACC_PUBLIC, "<init>", "()V", null, null);
      mv.visitCode();
      mv.visitVarInsn(Opcodes.ALOAD, 0);
      mv.visitMethodInsn(Opcodes.INVOKESPECIAL, "java/lang/Object", "<init>", "()V", false);
      mv.visitInsn(Opcodes.RETURN);
      mv.visitMaxs(1, 1);
      mv.visitEnd();
    }
    {
      mv =
          cw.visitMethod(
              Opcodes.ACC_PUBLIC + Opcodes.ACC_STATIC,
              "main",
              "([Ljava/lang/String;)V",
              null,
              null);
      mv.visitCode();
      mv.visitFieldInsn(Opcodes.GETSTATIC, "java/lang/System", "err", "Ljava/io/PrintStream;");
      mv.visitLdcInsn("Hello");
      mv.visitMethodInsn(
          Opcodes.INVOKEVIRTUAL, "java/io/PrintStream", "println", "(Ljava/lang/String;)V", false);
      mv.visitInsn(Opcodes.RETURN);
      mv.visitMaxs(2, 1);
      mv.visitEnd();
    }
    cw.visitEnd();

    return cw.toByteArray();
  }
}