org.glowroot.agent.IbmJava6HackClassFileTransformer Maven / Gradle / Ivy
/*
* Copyright 2017-2018 the original author or authors.
*
* 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 org.glowroot.agent;
import java.lang.instrument.ClassFileTransformer;
import java.security.ProtectionDomain;
import org.glowroot.agent.shaded.org.checkerframework.checker.nullness.qual.Nullable;
import org.glowroot.agent.shaded.org.objectweb.asm.ClassReader;
import org.glowroot.agent.shaded.org.objectweb.asm.ClassVisitor;
import org.glowroot.agent.shaded.org.objectweb.asm.ClassWriter;
import org.glowroot.agent.shaded.org.objectweb.asm.MethodVisitor;
import org.glowroot.agent.shaded.org.slf4j.Logger;
import org.glowroot.agent.shaded.org.slf4j.LoggerFactory;
import static org.glowroot.agent.shaded.org.objectweb.asm.Opcodes.ACONST_NULL;
import static org.glowroot.agent.shaded.org.objectweb.asm.Opcodes.ARETURN;
import static org.glowroot.agent.shaded.org.objectweb.asm.Opcodes.ASM7;
class IbmJava6HackClassFileTransformer implements ClassFileTransformer {
private static final Logger logger =
LoggerFactory.getLogger(IbmJava6HackClassFileTransformer.class);
@Override
public byte /*@Nullable*/ [] transform(@Nullable ClassLoader loader, @Nullable String className,
@Nullable Class classBeingRedefined, @Nullable ProtectionDomain protectionDomain,
byte[] bytes) {
try {
if ("org.glowroot.agent.shaded.com.google/protobuf/UnsafeUtil".equals(className)) {
ClassWriter cw = new ClassWriter(0);
ClassVisitor cv = new IbmJava6HackClassVisitor(cw);
ClassReader cr = new ClassReader(bytes);
cr.accept(cv, 0);
return cw.toByteArray();
}
} catch (Throwable t) {
logger.error(t.getMessage(), t);
}
return null;
}
private static class IbmJava6HackClassVisitor extends ClassVisitor {
private final ClassWriter cw;
private IbmJava6HackClassVisitor(ClassWriter cw) {
super(ASM7, cw);
this.cw = cw;
}
@Override
public MethodVisitor visitMethod(int access, String name, String descriptor,
@Nullable String signature, String /*@Nullable*/ [] exceptions) {
MethodVisitor mv = cw.visitMethod(access, name, descriptor, signature, exceptions);
if (name.equals("getUnsafe")) {
mv.visitCode();
mv.visitInsn(ACONST_NULL);
mv.visitInsn(ARETURN);
mv.visitMaxs(1, 1);
mv.visitEnd();
return mv;
} else {
return mv;
}
}
}
}