1 /* 2 * ProGuard -- shrinking, optimization, obfuscation, and preverification 3 * of Java bytecode. 4 * 5 * Copyright (c) 2002-2009 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; 22 23 import proguard.classfile.*; 24 import proguard.classfile.util.MethodLinker; 25 import proguard.classfile.visitor.*; 26 27 28 /** 29 * This <code>ClassVisitor</code> and <code>MemberVisitor</code> 30 * marks classes and class members it visits. The marked elements 31 * will remain unchanged as necessary in the optimization step. 32 * 33 * @author Eric Lafortune 34 */ 35 public class KeepMarker 36 implements ClassVisitor, 37 MemberVisitor 38 { 39 // A visitor info flag to indicate the visitor accepter is being kept. 40 private static final Object KEPT = new Object(); 41 42 43 // Implementations for ClassVisitor. 44 visitProgramClass(ProgramClass programClass)45 public void visitProgramClass(ProgramClass programClass) 46 { 47 markAsKept(programClass); 48 } 49 50 visitLibraryClass(LibraryClass libraryClass)51 public void visitLibraryClass(LibraryClass libraryClass) 52 { 53 markAsKept(libraryClass); 54 } 55 56 57 // Implementations for MemberVisitor. 58 visitProgramField(ProgramClass programClass, ProgramField programField)59 public void visitProgramField(ProgramClass programClass, ProgramField programField) 60 { 61 markAsKept(programField); 62 } 63 64 visitProgramMethod(ProgramClass programClass, ProgramMethod programMethod)65 public void visitProgramMethod(ProgramClass programClass, ProgramMethod programMethod) 66 { 67 markAsKept(MethodLinker.lastMember(programMethod)); 68 } 69 70 visitLibraryField(LibraryClass libraryClass, LibraryField libraryField)71 public void visitLibraryField(LibraryClass libraryClass, LibraryField libraryField) 72 { 73 markAsKept(libraryField); 74 } 75 76 visitLibraryMethod(LibraryClass libraryClass, LibraryMethod libraryMethod)77 public void visitLibraryMethod(LibraryClass libraryClass, LibraryMethod libraryMethod) 78 { 79 markAsKept(MethodLinker.lastMember(libraryMethod)); 80 } 81 82 83 // Small utility methods. 84 markAsKept(VisitorAccepter visitorAccepter)85 private static void markAsKept(VisitorAccepter visitorAccepter) 86 { 87 visitorAccepter.setVisitorInfo(KEPT); 88 } 89 90 isKept(VisitorAccepter visitorAccepter)91 public static boolean isKept(VisitorAccepter visitorAccepter) 92 { 93 return MethodLinker.lastVisitorAccepter(visitorAccepter).getVisitorInfo() == KEPT; 94 } 95 } 96