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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.constant.visitor;
     22 
     23 import proguard.classfile.Clazz;
     24 import proguard.classfile.attribute.*;
     25 import proguard.classfile.attribute.visitor.*;
     26 import proguard.classfile.constant.*;
     27 import proguard.classfile.util.SimplifiedVisitor;
     28 
     29 /**
     30  * This ConstantVisitor and BootstrapMethodInfoVisitor travels from any invoke
     31  * dynamic constants or bootstrap method info entries that it visits to their
     32  * bootstrap method handle constants, and applies a given constant visitor.
     33  *
     34  * @author Eric Lafortune
     35  */
     36 public class BootstrapMethodHandleTraveler
     37 extends      SimplifiedVisitor
     38 implements   ConstantVisitor,
     39              AttributeVisitor,
     40              BootstrapMethodInfoVisitor
     41 {
     42     private ConstantVisitor bootstrapMethodHandleVisitor;
     43 
     44     // Field serving as a method argument.
     45     int bootstrapMethodAttributeIndex;
     46 
     47 
     48     /**
     49      * Creates a new BootstrapMethodHandleVisitor that will delegate to the
     50      * given constant visitor.
     51      */
     52     public BootstrapMethodHandleTraveler(ConstantVisitor bootstrapMethodHandleVisitor)
     53     {
     54         this.bootstrapMethodHandleVisitor = bootstrapMethodHandleVisitor;
     55     }
     56 
     57 
     58     // Implementations for ConstantVisitor.
     59 
     60     public void visitAnyConstant(Clazz clazz, Constant constant) {}
     61 
     62 
     63     public void visitInvokeDynamicConstant(Clazz clazz, InvokeDynamicConstant invokeDynamicConstant)
     64     {
     65         // Pass the method index.
     66         bootstrapMethodAttributeIndex =
     67             invokeDynamicConstant.u2bootstrapMethodAttributeIndex;
     68 
     69         // Delegate to the bootstrap method.
     70         clazz.attributesAccept(this);
     71     }
     72 
     73 
     74     // Implementations for AttributeVisitor.
     75 
     76     public void visitAnyAttribute(Clazz clazz, Attribute attribute) {}
     77 
     78 
     79     public void visitBootstrapMethodsAttribute(Clazz clazz, BootstrapMethodsAttribute bootstrapMethodsAttribute)
     80     {
     81         // Check bootstrap methods.
     82         bootstrapMethodsAttribute.bootstrapMethodEntryAccept(clazz,
     83                                                              bootstrapMethodAttributeIndex,
     84                                                              this);
     85     }
     86 
     87 
     88     // Implementations for BootstrapMethodInfoVisitor.
     89 
     90     public void visitBootstrapMethodInfo(Clazz clazz, BootstrapMethodInfo bootstrapMethodInfo)
     91     {
     92         // Check bootstrap method.
     93         clazz.constantPoolEntryAccept(bootstrapMethodInfo.u2methodHandleIndex,
     94                                       bootstrapMethodHandleVisitor);
     95     }
     96 }
     97