/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.apache.cassandra.continuations;
import java.lang.annotation.Annotation;
import java.lang.instrument.ClassFileTransformer;
import java.lang.instrument.IllegalClassFormatException;
import java.security.ProtectionDomain;
import java.util.List;
import java.util.Set;
import java.util.HashSet;
import java.util.StringTokenizer;
import org.objectweb.asm.ClassReader;
import org.objectweb.asm.tree.AnnotationNode;
import org.objectweb.asm.tree.ClassNode;
import org.objectweb.asm.tree.MethodNode;
import org.apache.commons.javaflow.bytecode.transformation.ResourceTransformer;
import org.apache.commons.javaflow.bytecode.transformation.bcel.BcelClassTransformer;
/**
* Author : Avinash Lakshman ( alakshman@facebook.com) & Prashant Malik ( pmalik@facebook.com )
*/
class ContinuationClassTransformer implements ClassFileTransformer
{
private static final String targetAnnotation_ = "Suspendable";
private ResourceTransformer transformer_;
public ContinuationClassTransformer(String agentArguments, ResourceTransformer transformer)
{
super();
transformer_ = transformer;
}
public byte[] transform(ClassLoader classLoader, String className, Class redefiningClass, ProtectionDomain domain, byte[] bytes) throws IllegalClassFormatException
{
/*
* Use the ASM class reader to see which classes support
* the Suspendable annotation. If they do then those
* classes need to have their bytecodes transformed for
* Continuation support.
*/
ClassReader classReader = new ClassReader(bytes);
ClassNode classNode = new ClassNode();
classReader.accept(classNode, true);
List<AnnotationNode> annotationNodes = classNode.visibleAnnotations;
for( AnnotationNode annotationNode : annotationNodes )
{
if (annotationNode.desc.contains(ContinuationClassTransformer.targetAnnotation_))
{
bytes = transformer_.transform(bytes);
}
}
return bytes;
}
}