1/*
2 * ProGuard -- shrinking, optimization, obfuscation, and preverification
3 *             of Java bytecode.
4 *
5 * Copyright (c) 2002-2013 Eric Lafortune (eric@graphics.cornell.edu)
6 *
7 * This program is free software; you can redistribute it and/or modify it
8 * under the terms of the GNU General Public License as published by the Free
9 * Software Foundation; either version 2 of the License, or (at your option)
10 * any later version.
11 *
12 * This program is distributed in the hope that it will be useful, but WITHOUT
13 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
15 * more details.
16 *
17 * You should have received a copy of the GNU General Public License along
18 * with this program; if not, write to the Free Software Foundation, Inc.,
19 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20 */
21package proguard.io;
22
23import proguard.classfile.*;
24import proguard.classfile.util.ClassUtil;
25
26import java.io.IOException;
27import java.util.Map;
28
29/**
30 * This DataEntryReader delegates to another DataEntryReader, renaming the
31 * data entries based on the renamed classes in the given ClassPool.
32 *
33 * @author Eric Lafortune
34 */
35public class DataEntryObfuscator implements DataEntryReader
36{
37    private final ClassPool       classPool;
38    private final Map             packagePrefixMap;
39    private final DataEntryReader dataEntryReader;
40
41
42    /**
43     * Creates a new DataEntryObfuscator.
44     * @param classPool        the class pool that maps from old names to new
45     *                         names.
46     * @param packagePrefixMap the map from old package prefixes to new package
47     *                         prefixes.
48     * @param dataEntryReader  the DataEntryReader to which calls will be
49     *                         delegated.
50     */
51    public DataEntryObfuscator(ClassPool       classPool,
52                               Map             packagePrefixMap,
53                               DataEntryReader dataEntryReader)
54    {
55        this.classPool        = classPool;
56        this.packagePrefixMap = packagePrefixMap;
57        this.dataEntryReader  = dataEntryReader;
58    }
59
60
61    // Implementations for DataEntryReader.
62
63    public void read(DataEntry dataEntry) throws IOException
64    {
65        // Delegate to the actual data entry reader.
66        dataEntryReader.read(renamedDataEntry(dataEntry));
67    }
68
69
70    /**
71     * Create a renamed data entry, if possible.
72     */
73    private DataEntry renamedDataEntry(DataEntry dataEntry)
74    {
75        String dataEntryName = dataEntry.getName();
76
77        // Try to find a corresponding class name by removing increasingly
78        // long suffixes.
79        for (int suffixIndex = dataEntryName.length() - 1;
80             suffixIndex > 0;
81             suffixIndex--)
82        {
83            char c = dataEntryName.charAt(suffixIndex);
84            if (!Character.isLetterOrDigit(c))
85            {
86                // Chop off the suffix.
87                String className = dataEntryName.substring(0, suffixIndex);
88
89                // Did we get to the package separator?
90                if (c == ClassConstants.INTERNAL_PACKAGE_SEPARATOR)
91                {
92                    break;
93                }
94
95                // Is there a class corresponding to the data entry?
96                Clazz clazz = classPool.getClass(className);
97                if (clazz != null)
98                {
99                    // Did the class get a new name?
100                    String newClassName = clazz.getName();
101                    if (!className.equals(newClassName))
102                    {
103                        // Return a renamed data entry.
104                        String newDataEntryName =
105                            newClassName + dataEntryName.substring(suffixIndex);
106
107                        return new RenamedDataEntry(dataEntry, newDataEntryName);
108                    }
109                    else
110                    {
111                        // Otherwise stop looking.
112                        return dataEntry;
113                    }
114                }
115            }
116        }
117
118        // Try to find a corresponding package name by increasingly removing
119        // more subpackages.
120        String packagePrefix = dataEntryName;
121        do
122        {
123            // Chop off the class name or the last subpackage name.
124            packagePrefix = ClassUtil.internalPackagePrefix(packagePrefix);
125
126            // Is there a package corresponding to the package prefix?
127            String newPackagePrefix = (String)packagePrefixMap.get(packagePrefix);
128            if (newPackagePrefix != null)
129            {
130                // Did the package get a new name?
131                if (!packagePrefix.equals(newPackagePrefix))
132                {
133                    // Return a renamed data entry.
134                    String newDataEntryName =
135                        newPackagePrefix + dataEntryName.substring(packagePrefix.length());
136
137                    return new RenamedDataEntry(dataEntry, newDataEntryName);
138                }
139                else
140                {
141                    // Otherwise stop looking.
142                    return dataEntry;
143                }
144            }
145        }
146        while (packagePrefix.length() > 0);
147
148        return dataEntry;
149    }
150}
151