obfuscator.java

ProGuard 是一个免费的 Java类文件的压缩

/*
 * ProGuard -- shrinking, optimization, obfuscation, and preverification
 *             of Java bytecode.
 *
 * Copyright (c) 2002-2007 Eric Lafortune ([e-mail])
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 2 of the License, or (at your option)
 * any later version.
 *
 *
 * This program 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 General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */
package proguard.obfuscate;

import proguard.*;
import proguard.classfile.*;
import proguard.classfile.constant.visitor.AllConstantVisitor;
import proguard.classfile.editor.*;
import proguard.classfile.util.*;
import proguard.classfile.visitor.*;

import java.io.*;
import java.util.*;

/**
 * This class can perform obfuscation of class pools according to a given
 * specification.
 *
 * @author Eric Lafortune
 */
public class Obfuscator
{
    private Configuration configuration;


    /**
     * Creates a new Obfuscator.
     */
    public Obfuscator(Configuration configuration)
    {
        this.configuration = configuration;
    }


    /**
     * Performs obfuscation of the given program class pool.
     */
    public void execute(ClassPool programClassPool,
                        ClassPool libraryClassPool) throws IOException
    {
        // Check if we have at least some keep commands.
        if (configuration.keep         == null &&
            configuration.applyMapping == null &&
            configuration.printMapping == null)
        {
            throw new IOException("You have to specify '-keep' options for the obfuscation step.");
        }

        // Clean up any old visitor info.
        programClassPool.classesAccept(new ClassCleaner());
        libraryClassPool.classesAccept(new ClassCleaner());

        // If the class member names have to correspond globally,
        // link all class members in all classes, otherwise
        // link all non-private methods in all class hierarchies.
        ClassVisitor memberInfoLinker =
            configuration.useUniqueClassMemberNames ?
                (ClassVisitor)new AllMemberVisitor(new MethodLinker()) :
                (ClassVisitor)new BottomClassFilter(new MethodLinker());

        programClassPool.classesAccept(memberInfoLinker);
        libraryClassPool.classesAccept(memberInfoLinker);

        // Create a visitor for marking the seeds.
        NameMarker nameMarker = new NameMarker();
        ClassPoolVisitor classPoolvisitor =
            ClassSpecificationVisitorFactory.createClassPoolVisitor(configuration.keep,
                                                                    nameMarker,
                                                                    nameMarker,
                                                                    false,
                                                                    false,
                                                                    true);
        // Mark the seeds.
        programClassPool.accept(classPoolvisitor);
        libraryClassPool.accept(classPoolvisitor);

        // All library classes and library class members keep their names.
        libraryClassPool.classesAccept(nameMarker);
        libraryClassPool.classesAccept(new AllMemberVisitor(nameMarker));

        // Apply the mapping, if one has been specified. The mapping can
        // override the names of library classes and of library class members.
        if (configuration.applyMapping != null)
        {
            WarningPrinter warningPrinter = configuration.warn ?
                new WarningPrinter(System.err) :
                null;

            MappingReader reader = new MappingReader(configuration.applyMapping);

            MappingProcessor keeper =
                new MultiMappingProcessor(new MappingProcessor[]
                {
                    new MappingKeeper(programClassPool, warningPrinter),
                    new MappingKeeper(libraryClassPool, null),
                });

            reader.pump(keeper);

            if (configuration.warn)
            {
                // Print out a summary of the warnings if necessary.
                int mappingWarningCount = warningPrinter.getWarningCount();
                if (mappingWarningCount > 0)
                {
                    System.err.println("Warning: there were " + mappingWarningCount +
                                       " kept classes and class members that were remapped anyway.");
                    System.err.println("         You should adapt your configuration or edit the mapping file.");

                    if (!configuration.ignoreWarnings)
                    {
                        System.err.println("         If you are sure this remapping won't hurt,");
                        System.err.println("         you could try your luck using the '-ignorewarnings' option.");
                        throw new IOException("Please correct the above warnings first.");
                    }
                }
            }
        }

        // Mark attributes that have to be kept.
        AttributeUsageMarker attributeUsageMarker = new AttributeUsageMarker();
        if (configuration.keepAttributes != null)
        {
            if (!configuration.keepAttributes.isEmpty())
            {
                attributeUsageMarker.setKeepAttributes(configuration.keepAttributes);
            }
            else
            {
                attributeUsageMarker.setKeepAllAttributes();
            }
        }
        programClassPool.classesAccept(attributeUsageMarker);

        // Remove the attributes that can be discarded.
        programClassPool.classesAccept(new AttributeShrinker());

        // Come up with new names for all classes.
        programClassPool.classesAccept(new ClassObfuscator(programClassPool,
                                                           configuration.useMixedCaseClassNames,
                                                           configuration.flattenPackageHierarchy,
                                                           configuration.repackageClasses));

        // Come up with new names for all class members.
        NameFactory nameFactory = new SimpleNameFactory();

        if (configuration.obfuscationDictionary != null)
        {
            nameFactory = new DictionaryNameFactory(configuration.obfuscationDictionary,
                                                    nameFactory);
        }

        WarningPrinter warningPrinter = configuration.warn ?
            new WarningPrinter(System.err) :
            null;

        // Maintain a map of names to avoid [descriptor - new name - old name].
        Map descriptorMap = new HashMap();

        // Do the class member names have to be globally unique?
        if (configuration.useUniqueClassMemberNames)
        {
            // Collect all member names in all classes.
            programClassPool.classesAccept(
                new AllMemberVisitor(
                new MemberNameCollector(configuration.overloadAggressively,
                                        descriptorMap)));

            // Assign new names to all members in all classes.
            programClassPool.classesAccept(
                new AllMemberVisitor(
                new MemberObfuscator(configuration.overloadAggressively,
                                     nameFactory,
                                     descriptorMap)));
        }
        else
        {
            // Come up with new names for all non-private class members.
            programClassPool.classesAccept(
                new MultiClassVisitor(new ClassVisitor[]
                {
                    // Collect all private member names in this class and down
                    // the hierarchy.
                    new ClassHierarchyTraveler(true, false, false, true,
                    new AllMemberVisitor(
                    new MemberAccessFilter(ClassConstants.INTERNAL_ACC_PRIVATE, 0,
                    new MemberNameCollector(configuration.overloadAggressively,
                                            descriptorMap)))),

                    // Collect all non-private member names anywhere in the hierarchy.
                    new ClassHierarchyTraveler(true, true, true, true,
                    new AllMemberVisitor(