InstructionAdder.java revision cfead78069f3dc32998dc118ee08cab3867acea2 
1/*
2 * ProGuard -- shrinking, optimization, obfuscation, and preverification
3 *             of Java bytecode.
4 *
5 * Copyright (c) 2002-2011 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.instruction.visitor.InstructionVisitor;
26import proguard.classfile.instruction.*;
27import proguard.classfile.util.SimplifiedVisitor;
28
29/**
30 * This InstructionVisitor adds all instructions that it visits to the given
31 * target code attribute.
32 *
33 * @author Eric Lafortune
34 */
35public class InstructionAdder
36extends      SimplifiedVisitor
37implements   InstructionVisitor
38{
39    private final ConstantAdder         constantAdder;
40    private final CodeAttributeComposer codeAttributeComposer;
41
42
43    /**
44     * Creates a new InstructionAdder that will copy classes into the given
45     * target code attribute.
46     */
47    public InstructionAdder(ProgramClass          targetClass,
48                            CodeAttributeComposer targetComposer)
49    {
50        constantAdder         = new ConstantAdder(targetClass);
51        codeAttributeComposer = targetComposer;
52    }
53
54
55    // Implementations for InstructionVisitor.
56
57
58    public void visitAnyInstruction(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset, Instruction instruction)
59    {
60        // Add the instruction.
61        codeAttributeComposer.appendInstruction(offset, instruction);
62    }
63
64
65    public void visitConstantInstruction(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset, ConstantInstruction constantInstruction)
66    {
67        // Create a copy of the instruction.
68        Instruction newConstantInstruction =
69            new ConstantInstruction(constantInstruction.opcode,
70                                    constantAdder.addConstant(clazz, constantInstruction.constantIndex),
71                                    constantInstruction.constant).shrink();
72
73        // Add the instruction.
74        codeAttributeComposer.appendInstruction(offset, newConstantInstruction);
75    }
76}