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      1 /*
      2  * ProGuard -- shrinking, optimization, obfuscation, and preverification
      3  *             of Java bytecode.
      4  *
      5  * Copyright (c) 2002-2014 Eric Lafortune (eric (at) 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.classfile.visitor;
     22 
     23 import proguard.classfile.*;
     24 import proguard.classfile.util.*;
     25 
     26 /**
     27  * This <code>MemberVisitor</code> delegates its visits to another given
     28  * <code>MemberVisitor</code>, but only when the visited member is accessible
     29  * from the given referencing class.
     30  *
     31  * @author Eric Lafortune
     32  */
     33 public class MemberClassAccessFilter
     34 implements   MemberVisitor
     35 {
     36     private final Clazz         referencingClass;
     37     private final MemberVisitor memberVisitor;
     38 
     39 
     40     /**
     41      * Creates a new MemberAccessFilter.
     42      * @param referencingClass the class that is accessing the member.
     43      * @param memberVisitor    the <code>MemberVisitor</code> to which visits
     44      *                         will be delegated.
     45      */
     46     public MemberClassAccessFilter(Clazz         referencingClass,
     47                                    MemberVisitor memberVisitor)
     48     {
     49         this.referencingClass = referencingClass;
     50         this.memberVisitor    = memberVisitor;
     51     }
     52 
     53 
     54     // Implementations for MemberVisitor.
     55 
     56     public void visitProgramField(ProgramClass programClass, ProgramField programField)
     57     {
     58         if (accepted(programClass, programField.getAccessFlags()))
     59         {
     60             memberVisitor.visitProgramField(programClass, programField);
     61         }
     62     }
     63 
     64 
     65     public void visitProgramMethod(ProgramClass programClass, ProgramMethod programMethod)
     66     {
     67         if (accepted(programClass, programMethod.getAccessFlags()))
     68         {
     69             memberVisitor.visitProgramMethod(programClass, programMethod);
     70         }
     71     }
     72 
     73 
     74     public void visitLibraryField(LibraryClass libraryClass, LibraryField libraryField)
     75     {
     76         if (accepted(libraryClass, libraryField.getAccessFlags()))
     77         {
     78             memberVisitor.visitLibraryField(libraryClass, libraryField);
     79         }
     80     }
     81 
     82 
     83     public void visitLibraryMethod(LibraryClass libraryClass, LibraryMethod libraryMethod)
     84     {
     85         if (accepted(libraryClass, libraryMethod.getAccessFlags()))
     86         {
     87             memberVisitor.visitLibraryMethod(libraryClass, libraryMethod);
     88         }
     89     }
     90 
     91 
     92     // Small utility methods.
     93 
     94     private boolean accepted(Clazz clazz, int memberAccessFlags)
     95     {
     96         int accessLevel = AccessUtil.accessLevel(memberAccessFlags);
     97 
     98         return
     99             (accessLevel >= AccessUtil.PUBLIC                                                              ) ||
    100             (accessLevel >= AccessUtil.PRIVATE         && referencingClass.equals(clazz)                   ) ||
    101             (accessLevel >= AccessUtil.PACKAGE_VISIBLE && (ClassUtil.internalPackageName(referencingClass.getName()).equals(
    102                                                            ClassUtil.internalPackageName(clazz.getName())))) ||
    103             (accessLevel >= AccessUtil.PROTECTED       && (referencingClass.extends_(clazz)                  ||
    104                                                            referencingClass.extendsOrImplements(clazz))            );
    105     }
    106 }
    107