| /* |
| * ProGuard -- shrinking, optimization, obfuscation, and preverification |
| * of Java bytecode. |
| * |
| * Copyright (c) 2002-2017 Eric Lafortune @ GuardSquare |
| * |
| * 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.obfuscate; |
| |
| import proguard.classfile.*; |
| import proguard.classfile.attribute.*; |
| import proguard.classfile.attribute.visitor.AttributeVisitor; |
| import proguard.classfile.util.SimplifiedVisitor; |
| import proguard.classfile.visitor.*; |
| |
| import java.util.Arrays; |
| |
| /** |
| * This ClassVisitor removes attributes that are not marked as being used or |
| * required. |
| * |
| * @see AttributeUsageMarker |
| * |
| * @author Eric Lafortune |
| */ |
| public class AttributeShrinker |
| extends SimplifiedVisitor |
| implements ClassVisitor, |
| MemberVisitor, |
| AttributeVisitor |
| { |
| // Implementations for ClassVisitor. |
| |
| public void visitProgramClass(ProgramClass programClass) |
| { |
| // Compact the array for class attributes. |
| programClass.u2attributesCount = |
| shrinkArray(programClass.attributes, |
| programClass.u2attributesCount); |
| |
| // Compact the attributes in fields, methods, and class attributes, |
| programClass.fieldsAccept(this); |
| programClass.methodsAccept(this); |
| programClass.attributesAccept(this); |
| } |
| |
| |
| public void visitLibraryClass(LibraryClass libraryClass) |
| { |
| // Library classes are left unchanged. |
| } |
| |
| |
| // Implementations for MemberVisitor. |
| |
| public void visitProgramMember(ProgramClass programClass, ProgramMember programMember) |
| { |
| // Compact the attributes array. |
| programMember.u2attributesCount = |
| shrinkArray(programMember.attributes, |
| programMember.u2attributesCount); |
| |
| // Compact any attributes of the remaining attributes. |
| programMember.attributesAccept(programClass, this); |
| } |
| |
| |
| // Implementations for AttributeVisitor. |
| |
| public void visitAnyAttribute(Clazz clazz, Attribute attribute) {} |
| |
| |
| public void visitCodeAttribute(Clazz clazz, Method method, CodeAttribute codeAttribute) |
| { |
| // Compact the attributes array. |
| codeAttribute.u2attributesCount = |
| shrinkArray(codeAttribute.attributes, |
| codeAttribute.u2attributesCount); |
| } |
| |
| |
| // Small utility methods. |
| |
| /** |
| * Removes all VisitorAccepter objects that are not marked as being used |
| * from the given array. |
| * @return the new number of VisitorAccepter objects. |
| */ |
| private static int shrinkArray(VisitorAccepter[] array, int length) |
| { |
| int counter = 0; |
| |
| // Shift the used objects together. |
| for (int index = 0; index < length; index++) |
| { |
| if (AttributeUsageMarker.isUsed(array[index])) |
| { |
| array[counter++] = array[index]; |
| } |
| } |
| |
| // Clear the remaining array elements. |
| Arrays.fill(array, counter, length, null); |
| |
| return counter; |
| } |
| } |