net.java.truelicense.maven.plugin.obfuscation.Processor Maven / Gradle / Ivy

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Provides a Maven plugin with goals for the obfuscation of constant string values in Java class and test-class files (byte code).
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/*
 * Copyright (C) 2005-2013 Schlichtherle IT Services.
 * All rights reserved. Use is subject to license terms.
 */
package net.java.truelicense.maven.plugin.obfuscation;

import de.schlichtherle.truezip.file.TFile;
import java.io.File;
import java.util.Formatter;
import java.util.HashSet;
import java.util.Set;
import net.java.truelicense.obfuscate.Obfuscate;
import org.objectweb.asm.ClassVisitor;
import org.slf4j.Logger;

/**
 * Runs the obfuscation based on the configuration parameters provided to its
 * constructor(s).
 *
 * @author Christian Schlichtherle
 */
public final class Processor implements Runnable {

    /**
     * The default value of the {@code maxBytes} property, which is {@value}.
     *
     * @see #maxBytes()
     */
    public static final int DEFAULT_MAX_BYTES = 64 * 1024;

    /**
     * The default value of the {@code obfuscateAll} property, which is {@value}.
     *
     * @see #obfuscateAll()
     */
    public static final boolean DEFAULT_OBFUSCATE_ALL = false;

    /**
     * The default value of the {@code methodNameFormat} property, which is {@value}.
     *
     * @see #methodNameFormat()
     */
    public static final String DEFAULT_METHOD_NAME_FORMAT = "_%s#%d";

    /**
     * The default value of the {@code internStrings} property, which is {@value}.
     *
     * @see #internStrings()
     */
    public static final boolean DEFAULT_INTERN_STRINGS = true;

    private final Set constantStrings = new HashSet();

    private final Logger logger;
    private final TFile directory;
    private final int maxBytes;
    private final boolean obfuscateAll;
    private final String methodNameFormat;
    private final boolean internStrings;

    /**
     * Constructs a processor with the given parameters.
     * The constructed processor uses
     * {@link #DEFAULT_MAX_BYTES}, {@link #DEFAULT_OBFUSCATE_ALL},
     * {@link #DEFAULT_METHOD_NAME_FORMAT} and {@link #DEFAULT_INTERN_STRINGS}.
     *
     * @see #logger()
     * @see #directory()
     */
    public Processor(Logger logger, File directory) {
        this(logger, directory,
                DEFAULT_MAX_BYTES,
                DEFAULT_OBFUSCATE_ALL,
                DEFAULT_METHOD_NAME_FORMAT,
                DEFAULT_INTERN_STRINGS);
    }

    /**
     * Constructs a processor with the given parameters.
     *
     * @see #logger()
     * @see #directory()
     * @see #maxBytes()
     * @see #obfuscateAll()
     * @see #methodNameFormat()
     * @see #internStrings()
     */
    public Processor(
            final Logger logger,
            final File directory,
            final int maxBytes,
            final boolean obfuscateAll,
            final String methodNameFormat,
            final boolean internStrings) {
        this.obfuscateAll = obfuscateAll;
        if (null == (this.logger = logger)) throw new NullPointerException();
        this.directory = directory instanceof TFile
                ? (TFile) directory
                : new TFile(directory);
        if (0 >= (this.maxBytes = maxBytes))
            throw new IllegalArgumentException();
        if (null == (this.methodNameFormat = methodNameFormat))
            throw new NullPointerException();
        this.internStrings = internStrings;
    }

    /**
     * Returns the logger to use.
     * Any errors should be logged at the error level to enable subsequent
     * checking.
     */
    public Logger logger() { return logger; }

    /** Returns the directory to scan for class files to process. */
    public File directory() { return directory; }

    /** Returns the maximum allowed size of a class file in bytes. */
    public int maxBytes() { return maxBytes;  }

    /**
     * Returns {@code true} if all constant string values shall get obfuscated.
     * Otherwise only constant string values of fields annotated with
     * {@link Obfuscate} shall get obfuscated.
     *
     * @return Whether or not all constant string values shall get obfuscated.
     */
    public boolean obfuscateAll() { return obfuscateAll; }

    /**
     * Returns the methodName for synthesized method names.
     * This a methodName string for the class {@link Formatter}.
     * It's first parameter is a string identifier for the obfuscation stage
     * and its second parameter is an integer index for the synthesized method.
     */
    public String methodNameFormat() { return methodNameFormat; }

    /**
     * Returns whether or not a call to java.lang.String.intern()
     * shall get added when computing the original constant string values again.
     * Use this to preserve the identity relation of constant string values if
     * required.
     */
    public boolean internStrings() { return internStrings; }

    /**
     * Returns the set of constant strings to obfuscate.
     * The returned set is only used when {@link #obfuscateAll} is
     * {@code false} and is modifiable so as to exchange the set between
     * different processing paths.
     *
     * @return The set of constant strings to obfuscate.
     */
    @SuppressWarnings("ReturnOfCollectionOrArrayField")
    Set constantStrings() { return constantStrings; }

    Logger logger(String subject) {
        return new SubjectLogger(logger(), subject);
    }

    String methodName(String stage, int index) {
        return new Formatter().format(methodNameFormat(), stage, index).toString();
    }

    /** Runs the obfuscation processor. */
    @Override public void run() {
        firstPass().run();
        secondPass().run();
    }

    Runnable firstPass() { return new FirstPass(this); }
    Runnable secondPass() { return new SecondPass(this); }

    ClassVisitor collector() { return new Collector(this); }

    ClassVisitor obfuscator(ClassVisitor cv) {
        return new Obfuscator(this, cv);
    }

    ClassVisitor merger(ClassVisitor cv, String prefix) {
        return new Merger(this, prefix, cv);
    }
}