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  */
21 package proguard.optimize.peephole;
22 
23 import proguard.classfile.*;
24 import proguard.classfile.util.SimplifiedVisitor;
25 import proguard.classfile.visitor.ClassVisitor;
26 import proguard.optimize.KeepMarker;
27 
28 /**
29  * This <code>ClassVisitor</code> makes the program classes that it visits
30  * final, if possible.
31  *
32  * @author Eric Lafortune
33  */
34 public class ClassFinalizer
35 extends      SimplifiedVisitor
36 implements   ClassVisitor
37 {
38     private final ClassVisitor extraClassVisitor;
39 
40 
41     /**
42      * Creates a new ClassFinalizer.
43      */
ClassFinalizer()44     public ClassFinalizer()
45     {
46         this(null);
47     }
48 
49 
50     /**
51      * Creates a new ClassFinalizer.
52      * @param extraClassVisitor an optional extra visitor for all finalized
53      *                          classes.
54      */
ClassFinalizer(ClassVisitor extraClassVisitor)55     public ClassFinalizer(ClassVisitor  extraClassVisitor)
56     {
57         this.extraClassVisitor = extraClassVisitor;
58     }
59 
60 
61     // Implementations for ClassVisitor.
62 
visitProgramClass(ProgramClass programClass)63     public void visitProgramClass(ProgramClass programClass)
64     {
65         // If the class is not final/interface/abstract,
66         // and it is not being kept,
67         // and it doesn't have any subclasses,
68         // then make it final.
69         if ((programClass.u2accessFlags & (ClassConstants.ACC_FINAL     |
70                                            ClassConstants.ACC_INTERFACE |
71                                            ClassConstants.ACC_ABSTRACT)) == 0 &&
72             !KeepMarker.isKept(programClass)                                           &&
73             programClass.subClasses == null)
74         {
75             programClass.u2accessFlags |= ClassConstants.ACC_FINAL;
76 
77             // Visit the class, if required.
78             if (extraClassVisitor != null)
79             {
80                 extraClassVisitor.visitProgramClass(programClass);
81             }
82         }
83     }
84 }
85