1/*
2 * ProGuard -- shrinking, optimization, obfuscation, and preverification
3 *             of Java bytecode.
4 *
5 * Copyright (c) 2002-2014 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.classfile.editor;
22
23import proguard.classfile.*;
24import proguard.classfile.attribute.*;
25import proguard.classfile.attribute.visitor.AttributeVisitor;
26import proguard.classfile.constant.Utf8Constant;
27import proguard.classfile.util.*;
28import proguard.classfile.visitor.ClassVisitor;
29
30import java.util.Arrays;
31
32/**
33 * This ClassVisitor removes specified interfaces from the classes and class
34 * signatures that it visits.
35 *
36 * @author Eric Lafortune
37 */
38public class InterfaceDeleter
39extends      SimplifiedVisitor
40implements   ClassVisitor,
41             AttributeVisitor
42{
43    private static final boolean DEBUG = false;
44
45
46    private final boolean[] delete;
47
48
49    /**
50     * Creates a new InterfaceDeleter to remove the specified interfaces.
51     * @param delete an array that corresponds to the interfaces of a class
52     *               and that specifies the ones to be removed.
53     */
54    public InterfaceDeleter(boolean[] delete)
55    {
56        this.delete = delete;
57    }
58
59
60    // Implementations for ClassVisitor.
61
62    public void visitProgramClass(ProgramClass programClass)
63    {
64        int[] interfaces      = programClass.u2interfaces;
65        int   interfacesCount = programClass.u2interfacesCount;
66
67        if (DEBUG)
68        {
69            System.out.println("InterfaceDeleter: "+programClass.getName()+" ("+interfacesCount+" interfaces)");
70        }
71
72        // Copy the interfaces that aren't deleted.
73        int newInterfacesCount = 0;
74        for (int index = 0; index < interfacesCount; index++)
75        {
76            if (DEBUG)
77            {
78                System.out.println("InterfaceDeleter:   "+(delete[index]?"- ":"+ ")+programClass.getInterfaceName(index));
79            }
80
81            if (!delete[index])
82            {
83                interfaces[newInterfacesCount++] = interfaces[index];
84            }
85        }
86
87        // Update the signature.
88        if (newInterfacesCount < interfacesCount)
89        {
90            programClass.u2interfacesCount = newInterfacesCount;
91
92            programClass.attributesAccept(this);
93        }
94    }
95
96
97    // Implementations for AttributeVisitor.
98
99    public void visitAnyAttribute(Clazz clazz, Attribute attribute) {}
100
101
102    public void visitSignatureAttribute(Clazz clazz, SignatureAttribute signatureAttribute)
103    {
104        Clazz[] referencedClasses = signatureAttribute.referencedClasses;
105        if (referencedClasses != null)
106        {
107            // Process the generic definitions, superclass, and implemented
108            // interfaces.
109            InternalTypeEnumeration internalTypeEnumeration =
110                new InternalTypeEnumeration(signatureAttribute.getSignature(clazz));
111
112            // Recompose the signature types in a string buffer.
113            StringBuffer newSignatureBuffer = new StringBuffer();
114
115            // Also update the array with referenced classes.
116            int referencedClassIndex    = 0;
117            int newReferencedClassIndex = 0;
118
119            // Copy the variable type declarations and the super class type.
120            while (internalTypeEnumeration.hasMoreTypes())
121            {
122                String internalType = internalTypeEnumeration.nextType();
123
124                // Append the type.
125                newSignatureBuffer.append(internalType);
126
127                // Copy any referenced classes.
128                int classCount =
129                    new DescriptorClassEnumeration(internalType).classCount();
130
131                for (int counter = 0; counter < classCount; counter++)
132                {
133                    referencedClasses[newReferencedClassIndex++] =
134                        referencedClasses[referencedClassIndex++];
135                }
136
137                if (DEBUG)
138                {
139                    System.out.println("InterfaceDeleter:   type = " + internalType + " (" + classCount + " referenced classes)");
140                }
141
142                if (ClassUtil.isInternalClassType(internalType))
143                {
144                    break;
145                }
146            }
147
148            // Copy the interface types.
149            int index = 0;
150            while (internalTypeEnumeration.hasMoreTypes())
151            {
152                String internalType = internalTypeEnumeration.nextType();
153
154                int classCount =
155                    new DescriptorClassEnumeration(internalType).classCount();
156
157                if (DEBUG)
158                {
159                    System.out.println("InterfaceDeleter:   type " + (delete[index] ? "- " : "+ ") + internalType + " (" + classCount + " referenced classes)");
160                }
161
162                if (!delete[index++])
163                {
164                    // Append the type.
165                    newSignatureBuffer.append(internalType);
166
167                    // Copy any referenced classes.
168                    for (int counter = 0; counter < classCount; counter++)
169                    {
170                        referencedClasses[newReferencedClassIndex++] =
171                            referencedClasses[referencedClassIndex++];
172                    }
173                }
174                else
175                {
176                    referencedClassIndex += classCount;
177                }
178            }
179
180            // Update the signature.
181            ((Utf8Constant)((ProgramClass)clazz).constantPool[signatureAttribute.u2signatureIndex]).setString(newSignatureBuffer.toString());
182
183            // Clear the remaining referenced classes.
184            Arrays.fill(referencedClasses,
185                        newReferencedClassIndex,
186                        referencedClassIndex,
187                        null);
188        }
189    }
190}
191