com.develorium.metracer.statik.MetracerClassFileTransformer.java Source code

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Here is the source code for com.develorium.metracer.statik.MetracerClassFileTransformer.java

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/*
 * Copyright 2015-2016 Michael Kocherov
 *
 * 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 com.develorium.metracer.statik;

import java.lang.instrument.*;
import java.security.ProtectionDomain;
import java.util.*;
import java.util.regex.*;
import org.objectweb.asm.*;
import org.objectweb.asm.tree.*;
import com.develorium.metracer.*;
import com.develorium.metracer.asm.*;

public class MetracerClassFileTransformer implements ClassFileTransformer {
    private Patterns patterns = null;
    private RuntimeLogger runtimeLogger = new RuntimeLogger();
    private com.develorium.metracer.Runtime runtime = new com.develorium.metracer.Runtime(runtimeLogger);

    public MetracerClassFileTransformer(String theArguments) {
        if (theArguments == null)
            throw new RuntimeException("Arguments are missing");

        patterns = new Patterns(theArguments, null, StackTraceMode.DISABLED);
    }

    @Override
    public byte[] transform(ClassLoader theLoader, String theClassName, Class<?> theClassBeingRedefined,
            ProtectionDomain theProtectionDomain, byte[] theClassfileBuffer) throws IllegalClassFormatException {
        if (theClassName.startsWith("java/lang"))
            return theClassfileBuffer;

        try {
            InstrumentClassResult icr = instrumentClass(theClassfileBuffer,
                    theLoader != null ? theLoader : getClass().getClassLoader());

            if (icr.hasSlf4jLogger)
                runtimeLogger.registerClassWithSlf4jLogger(theClassName.replaceAll("/", "."), theLoader);

            theClassfileBuffer = icr.bytecode;
        } catch (Throwable t) {
            System.err.format("Failed to instrument class %1$s, loader %2$s, error message: %3$s\n", theClassName,
                    theLoader, t.toString());
            t.printStackTrace();
        }

        return theClassfileBuffer;
    }

    private static class InstrumentClassResult {
        byte[] bytecode = null;
        boolean hasSlf4jLogger = false;
    }

    private InstrumentClassResult instrumentClass(byte theBytecode[], ClassLoader theLoader) {
        ClassReader reader = new ClassReader(theBytecode);
        ClassNode parsedClass = new ClassNode();
        reader.accept(parsedClass, 0);

        MetracerClassWriter writer = new MetracerClassWriter(reader, theLoader);
        MetracerClassVisitor visitor = new MetracerClassVisitor(writer, theLoader, patterns, parsedClass);
        reader.accept(visitor, ClassReader.EXPAND_FRAMES);

        InstrumentClassResult rv = new InstrumentClassResult();
        rv.bytecode = visitor.getIsChanged() ? writer.toByteArray() : theBytecode;
        rv.hasSlf4jLogger = visitor.getHasSlf4Logger();
        return rv;
    }
}