summaryrefslogtreecommitdiff
path: root/src/proguard/optimize/peephole/RetargetedInnerClassAttributeRemover.java
blob: 6707a12c1c35cca7dc3c0df22fc7da5f05ab002a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
/*
 * ProGuard -- shrinking, optimization, obfuscation, and preverification
 *             of Java bytecode.
 *
 * Copyright (c) 2002-2009 Eric Lafortune (eric@graphics.cornell.edu)
 *
 * 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.optimize.peephole;

import proguard.classfile.*;
import proguard.classfile.attribute.*;
import proguard.classfile.attribute.visitor.*;
import proguard.classfile.constant.ClassConstant;
import proguard.classfile.constant.visitor.ConstantVisitor;
import proguard.classfile.util.SimplifiedVisitor;
import proguard.classfile.visitor.ClassVisitor;

/**
 * This ClassVisitor removes InnerClasses and EnclosingMethod attributes in
 * classes that are retargeted or that refer to classes that are retargeted.
 *
 * @see ClassMerger
 * @author Eric Lafortune
 */
public class RetargetedInnerClassAttributeRemover
extends      SimplifiedVisitor
implements   ClassVisitor,
             AttributeVisitor,
             InnerClassesInfoVisitor,
             ConstantVisitor
{
    private boolean retargeted;


    // Implementations for ClassVisitor.

    public void visitProgramClass(ProgramClass programClass)
    {
        int         attributesCount = programClass.u2attributesCount;
        Attribute[] attributes      = programClass.attributes;

        int newAtributesCount = 0;

        // Copy over all non-retargeted attributes.
        for (int index = 0; index < attributesCount; index++)
        {
            Attribute attribute = attributes[index];

            // Check if it's an InnerClasses or EnclosingMethod attribute in
            // a retargeted class or referring to a retargeted class.
            retargeted = false;
            attribute.accept(programClass, this);
            if (!retargeted)
            {
                attributes[newAtributesCount++] = attribute;
            }
        }

        // Clean up any remaining array elements.
        for (int index = newAtributesCount; index < attributesCount; index++)
        {
            attributes[index] = null;
        }

        // Update the number of attribuets.
        programClass.u2attributesCount = newAtributesCount;
    }


    // Implementations for AttributeVisitor.

    public void visitAnyAttribute(Clazz clazz, Attribute attribute) {}


    public void visitInnerClassesAttribute(Clazz clazz, InnerClassesAttribute innerClassesAttribute)
    {
        // Check whether the class itself is retargeted.
        checkTarget(clazz);

        // Check whether the referenced classes are retargeted.
        innerClassesAttribute.innerClassEntriesAccept(clazz, this);
    }


    public void visitEnclosingMethodAttribute(Clazz clazz, EnclosingMethodAttribute enclosingMethodAttribute)
    {
        // Check whether the class itself is retargeted.
        checkTarget(clazz);

        // Check whether the referenced class is retargeted.
        checkTarget(enclosingMethodAttribute.referencedClass);
    }


    // Implementations for InnerClassesInfoVisitor.

    public void visitInnerClassesInfo(Clazz clazz, InnerClassesInfo innerClassesInfo)
    {
        // Check whether the inner class or the outer class are retargeted.
        innerClassesInfo.innerClassConstantAccept(clazz, this);
        innerClassesInfo.outerClassConstantAccept(clazz, this);
    }


    // Implementations for ConstantVisitor.

    public void visitClassConstant(Clazz clazz, ClassConstant classConstant)
    {
        // Check whether the referenced class is retargeted.
        checkTarget(classConstant.referencedClass);
    }


    // Small utility methods.

    /**
     * Sets the global return value to true if the given class is retargeted.
     */
    private void checkTarget(Clazz clazz)
    {
        if (clazz != null &&
            ClassMerger.getTargetClass(clazz) != null)
        {
            retargeted = true;
        }
    }
}