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/*
* ProGuard -- shrinking, optimization, obfuscation, and preverification
* of Java bytecode.
*
* Copyright (c) 2002-2013 Eric Lafortune (eric@graphics.cornell.edu)
*
* 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.classfile.util;
import proguard.classfile.*;
import proguard.classfile.attribute.Attribute;
import proguard.classfile.attribute.visitor.AttributeVisitor;
import proguard.classfile.constant.*;
import proguard.classfile.constant.visitor.ConstantVisitor;
import proguard.classfile.visitor.ClassVisitor;
/**
* This ClassVisitor shares strings in the class files that it visits.
*
* @author Eric Lafortune
*/
public class StringSharer
extends SimplifiedVisitor
implements ClassVisitor,
ConstantVisitor,
AttributeVisitor
{
// A fields acting as an argument for the visitor methods.
private String name;
private String type;
// Implementations for ClassVisitor.
public void visitProgramClass(ProgramClass programClass)
{
// Replace name strings in the constant pool by shared strings.
programClass.constantPoolEntriesAccept(this);
// Replace attribute name strings in the constant pool by internalized
// strings.
programClass.attributesAccept(this);
}
public void visitLibraryClass(LibraryClass libraryClass)
{
// Replace the super class name string by the shared name string.
Clazz superClass = libraryClass.superClass;
if (superClass != null)
{
libraryClass.superClassName = superClass.getName();
}
// Replace the interface name strings by the shared name strings.
if (libraryClass.interfaceNames != null)
{
String[] interfaceNames = libraryClass.interfaceNames;
Clazz[] interfaceClasses = new Clazz[interfaceNames.length];
for (int index = 0; index < interfaceNames.length; index++)
{
// Keep a reference to the interface class.
Clazz interfaceClass = interfaceClasses[index];
if (interfaceClass != null)
{
interfaceNames[index] = interfaceClass.getName();
}
}
}
}
// Implementations for ConstantVisitor.
public void visitAnyConstant(Clazz clazz, Constant constant) {}
public void visitStringConstant(Clazz clazz, StringConstant stringConstant)
{
Member referencedMember = stringConstant.referencedMember;
if (referencedMember != null)
{
Clazz referencedClass = stringConstant.referencedClass;
// Put the actual class member's name in the class pool.
name = referencedMember.getName(referencedClass);
clazz.constantPoolEntryAccept(stringConstant.u2stringIndex, this);
}
}
public void visitAnyRefConstant(Clazz clazz, RefConstant refConstant)
{
Member referencedMember = refConstant.referencedMember;
if (referencedMember != null)
{
Clazz referencedClass = refConstant.referencedClass;
// Put the actual class member's name and type strings in the class
// pool.
name = referencedMember.getName(referencedClass);
type = referencedMember.getDescriptor(referencedClass);
clazz.constantPoolEntryAccept(refConstant.u2nameAndTypeIndex, this);
}
}
public void visitNameAndTypeConstant(Clazz clazz, NameAndTypeConstant nameAndTypeConstant)
{
if (name != null)
{
// Put the actual class member's name and type strings in the class
// pool.
clazz.constantPoolEntryAccept(nameAndTypeConstant.u2nameIndex, this);
name = type;
clazz.constantPoolEntryAccept(nameAndTypeConstant.u2descriptorIndex, this);
}
}
public void visitClassConstant(Clazz clazz, ClassConstant classConstant)
{
Clazz referencedClass = classConstant.referencedClass;
if (referencedClass != null)
{
// Put the actual class's name string in the class pool.
name = referencedClass.getName();
clazz.constantPoolEntryAccept(classConstant.u2nameIndex, this);
}
}
public void visitUtf8Constant(Clazz clazz, Utf8Constant utf8Constant)
{
// Do we have a new string to put into this constant?
if (name != null)
{
// Replace the string, if it's actually the same.
if (name.equals(utf8Constant.getString()))
{
utf8Constant.setString(name);
}
name = null;
}
}
// Implementations for AttributeVisitor.
public void visitAnyAttribute(Clazz clazz, Attribute attribute)
{
// Put the internalized attribute's name string in the class pool.
name = attribute.getAttributeName(clazz).intern();
clazz.constantPoolEntryAccept(attribute.u2attributeNameIndex, this);
}
}
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