edu.berkeley.cs.jqf.instrument.InstrumentingClassLoader Maven / Gradle / Ivy

Show more of this group Show more artifacts with this name
Show all versions of jqf-instrument Show documentation
JQF: Feedback-directed Quickcheck for Java - Instrumentation and event generation module
There is a newer version: 2.0
/*
 * Copyright (c) 2017-2018 The Regents of the University of California
 *
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 * 1. Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
package edu.berkeley.cs.jqf.instrument;

import java.io.BufferedInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.lang.instrument.ClassFileTransformer;
import java.lang.instrument.IllegalClassFormatException;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLClassLoader;

import janala.instrument.SnoopInstructionTransformer;

/**
 * @author Rohan Padhye
 */
public class InstrumentingClassLoader extends URLClassLoader {

    private ClassFileTransformer transformer = new SnoopInstructionTransformer();

    public InstrumentingClassLoader(URL[] urls, ClassLoader parent) {
        super(urls, parent);
    }

    public InstrumentingClassLoader(String[] paths, ClassLoader parent) throws MalformedURLException {
        this(stringsToUrls(paths), parent);
    }

    private static URL[] stringsToUrls(String[] paths) throws MalformedURLException {
        URL[] urls = new URL[paths.length];
        for (int i = 0; i < paths.length; i++) {
            urls[i] = new File(paths[i]).toURI().toURL();
        }
        return urls;
    }


    @Override
    public Class findClass(String name) throws ClassNotFoundException {
        byte[] bytes;

        // Try to read the class file in as a resource
        String internalName = name.replace('.', '/');
        String path = internalName.concat(".class");
        try (InputStream in = super.getResourceAsStream(path)) {
            if (in == null) {
                throw new ClassNotFoundException("Cannot find class " + name);
            }
            BufferedInputStream buf = new BufferedInputStream(in);

            ByteArrayOutputStream baos = new ByteArrayOutputStream();
            int b;
            while ((b = buf.read()) != -1) {
                baos.write(b);
            }
            bytes = baos.toByteArray();
        } catch (IOException e) {
            throw new ClassNotFoundException("I/O exception while loading class.", e);
        }

        assert (bytes != null);

        byte[] transformedBytes;
        try {
            transformedBytes = transformer.transform(this, internalName, null, null, bytes);
        } catch (IllegalClassFormatException e) {
            // Just use original bytes
            transformedBytes = null;
        }


        // Load the class with transformed bytes, if possible
        if (transformedBytes != null) {
            bytes = transformedBytes;
        }
        return defineClass(name, bytes,
                0, bytes.length);
    }

}