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.classfile.editor;
22
23import proguard.classfile.*;
24import proguard.classfile.attribute.*;
25import proguard.classfile.attribute.visitor.*;
26import proguard.classfile.constant.*;
27import proguard.classfile.constant.visitor.ConstantVisitor;
28import proguard.classfile.util.*;
29import proguard.classfile.visitor.*;
30
31/**
32 * This ConstantVisitor fixes the access modifiers of all classes and class
33 * members that are referenced by the constants that it visits.
34 *
35 * @author Eric Lafortune
36 */
37public class AccessFixer
38extends      SimplifiedVisitor
39implements   ConstantVisitor,
40             ClassVisitor,
41             MemberVisitor
42{
43    private MyReferencedClassFinder referencedClassFinder = new MyReferencedClassFinder();
44
45    private Clazz referencingClass;
46    private Clazz referencedClass;
47
48
49    // Implementations for ConstantVisitor.
50
51    public void visitAnyConstant(Clazz clazz, Constant constant) {}
52
53
54    public void visitStringConstant(Clazz clazz, StringConstant stringConstant)
55    {
56        referencingClass = clazz;
57        referencedClass  = stringConstant.referencedClass;
58
59        // Make sure the access flags of the referenced class or class member,
60        // if any, are acceptable.
61        stringConstant.referencedClassAccept(this);
62        stringConstant.referencedMemberAccept(this);
63    }
64
65
66    public void visitInvokeDynamicConstant(Clazz clazz, InvokeDynamicConstant invokeDynamicConstant)
67    {
68        // Check the bootstrap method.
69        invokeDynamicConstant.bootstrapMethodHandleAccept(clazz, this);
70    }
71
72
73    public void visitMethodHandleConstant(Clazz clazz, MethodHandleConstant methodHandleConstant)
74    {
75        // Check the method reference.
76        clazz.constantPoolEntryAccept(methodHandleConstant.u2referenceIndex, this);
77    }
78
79
80    public void visitAnyRefConstant(Clazz clazz, RefConstant refConstant)
81    {
82        referencingClass = clazz;
83
84        // Remember the specified class, since it might be different from
85        // the referenced class that actually contains the class member.
86        clazz.constantPoolEntryAccept(refConstant.u2classIndex, referencedClassFinder);
87
88        // Make sure the access flags of the referenced class member are
89        // acceptable.
90        refConstant.referencedMemberAccept(this);
91    }
92
93
94    public void visitClassConstant(Clazz clazz, ClassConstant classConstant)
95    {
96        referencingClass = clazz;
97
98        // Make sure the access flags of the referenced class are acceptable.
99        classConstant.referencedClassAccept(this);
100    }
101
102
103    // Implementations for ClassVisitor.
104
105    public void visitLibraryClass(LibraryClass libraryClass) {}
106
107
108    public void visitProgramClass(ProgramClass programClass)
109    {
110        int currentAccessFlags = programClass.getAccessFlags();
111        int currentAccessLevel = AccessUtil.accessLevel(currentAccessFlags);
112
113        // Compute the required access level.
114        Clazz referencingClass = this.referencingClass;
115        int requiredAccessLevel =
116            inSamePackage(programClass, referencingClass) ? AccessUtil.PACKAGE_VISIBLE :
117                                                            AccessUtil.PUBLIC;
118
119        // Fix the class access flags if necessary.
120        if (currentAccessLevel < requiredAccessLevel)
121        {
122            programClass.u2accessFlags =
123                AccessUtil.replaceAccessFlags(currentAccessFlags,
124                                              AccessUtil.accessFlags(requiredAccessLevel));
125        }
126    }
127
128
129    // Implementations for MemberVisitor.
130
131    public void visitLibraryMember(LibraryClass libraryClass, LibraryMember libraryMember) {}
132
133
134    public void visitProgramMember(ProgramClass programClass, ProgramMember programMember)
135    {
136        int currentAccessFlags = programMember.getAccessFlags();
137        int currentAccessLevel = AccessUtil.accessLevel(currentAccessFlags);
138
139        // Compute the required access level.
140        int requiredAccessLevel =
141            programClass.equals(referencingClass)         ? AccessUtil.PRIVATE         :
142            inSamePackage(programClass, referencingClass) ? AccessUtil.PACKAGE_VISIBLE :
143            referencedClass.extends_(referencingClass) &&
144            referencingClass.extends_(programClass)       ? AccessUtil.PROTECTED       :
145                                                            AccessUtil.PUBLIC;
146
147        // Fix the class member access flags if necessary.
148        if (currentAccessLevel < requiredAccessLevel)
149        {
150            programMember.u2accessFlags =
151                AccessUtil.replaceAccessFlags(currentAccessFlags,
152                                              AccessUtil.accessFlags(requiredAccessLevel));
153        }
154    }
155
156
157    /**
158     * This ConstantVisitor returns the referenced class of the class constant
159     * that it visits.
160     */
161    private class MyReferencedClassFinder
162    extends       SimplifiedVisitor
163    implements    ConstantVisitor
164    {
165        // Implementations for ConstantVisitor.
166        public void visitClassConstant(Clazz clazz, ClassConstant classConstant)
167        {
168            referencedClass = classConstant.referencedClass;
169        }
170    }
171
172
173    // Small utility methods.
174
175    private boolean inSamePackage(ProgramClass class1, Clazz class2)
176    {
177        return ClassUtil.internalPackageName(class1.getName()).equals(
178               ClassUtil.internalPackageName(class2.getName()));
179    }
180}
181