org.evosuite.testcarver.instrument.Transformer.java Source code

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Here is the source code for org.evosuite.testcarver.instrument.Transformer.java

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/**
 * Copyright (C) 2010-2016 Gordon Fraser, Andrea Arcuri and EvoSuite
 * contributors
 *
 * This file is part of EvoSuite.
 *
 * EvoSuite is free software: you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as published
 * by the Free Software Foundation, either version 3.0 of the License, or
 * (at your option) any later version.
 *
 * EvoSuite 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
 * Lesser Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with EvoSuite. If not, see <http://www.gnu.org/licenses/>.
 */
package org.evosuite.testcarver.instrument;

import java.lang.instrument.ClassFileTransformer;
import java.lang.instrument.IllegalClassFormatException;
import java.security.ProtectionDomain;
import java.util.Arrays;
import java.util.HashSet;

import org.evosuite.testcarver.capture.Capturer;
import org.objectweb.asm.ClassReader;
import org.objectweb.asm.ClassWriter;
import org.objectweb.asm.tree.ClassNode;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class Transformer implements ClassFileTransformer {
    private final HashSet<String> classesToBeObserved;

    private final Instrumenter instrumenter;

    private static final Logger logger = LoggerFactory.getLogger(Transformer.class);

    public Transformer(final String[] namesOfClassesToBeObserved) {
        logger.debug("initialized transformer with namesOfClassesToBeObserved={}",
                new Object[] { Arrays.toString(namesOfClassesToBeObserved) });
        if (namesOfClassesToBeObserved == null) {
            throw new NullPointerException("Given array of names of classes to be observed must not be null");
        }

        this.classesToBeObserved = new HashSet<String>();

        final int size = namesOfClassesToBeObserved.length;
        for (int i = 0; i < size; i++) {
            this.classesToBeObserved.add(namesOfClassesToBeObserved[i].replace('.', '/'));
        }

        this.instrumenter = new Instrumenter();
    }

    @Override
    public byte[] transform(final ClassLoader loader, final String className, final Class<?> classBeingRedefined,
            final ProtectionDomain protectionDomain, final byte[] classFileBuffer)
            throws IllegalClassFormatException {
        logger.debug("transforming {}", className);

        if (!Capturer.isCapturing()) {
            logger.debug("class {} has not been transformed because Capturer is not active", className);
            return classFileBuffer;
        }

        if (!TransformerUtil.isClassConsideredForInstrumenetation(className)) {
            logger.debug("class {} has not been instrumented because its name is on the blacklist", className);
            return classFileBuffer;
        }

        final ClassReader cr = new ClassReader(classFileBuffer);
        final ClassWriter cw = new ClassWriter(ClassWriter.COMPUTE_MAXS);
        final ClassNode cn = new ClassNode();
        cr.accept(cn, ClassReader.SKIP_DEBUG);

        this.instrumenter.instrument(className, cn);

        cn.accept(cw);

        return cw.toByteArray();
    }
}