bb-tools/proguard4.7/src/proguard/optimize/peephole/TargetClassChanger.java
/*
* ProGuard -- shrinking, optimization, obfuscation, and preverification
* of Java bytecode.
*
* Copyright (c) 2002-2011 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.optimize.peephole;
import proguard.classfile.*;
import proguard.classfile.editor.*;
import proguard.classfile.attribute.*;
import proguard.classfile.attribute.annotation.*;
import proguard.classfile.attribute.annotation.visitor.*;
import proguard.classfile.attribute.visitor.*;
import proguard.classfile.constant.*;
import proguard.classfile.constant.visitor.ConstantVisitor;
import proguard.classfile.util.*;
import proguard.classfile.visitor.*;
/**
* This ClassVisitor replaces references to classes and class members if the
* classes have targets that are intended to replace them.
*
* @see VerticalClassMerger
* @see ClassReferenceFixer
* @see MemberReferenceFixer
* @author Eric Lafortune
*/
public class TargetClassChanger
extends SimplifiedVisitor
implements ClassVisitor,
ConstantVisitor,
MemberVisitor,
AttributeVisitor,
LocalVariableInfoVisitor,
LocalVariableTypeInfoVisitor,
AnnotationVisitor,
ElementValueVisitor
{
private static final boolean DEBUG = false;
// Implementations for ClassVisitor.
public void visitProgramClass(ProgramClass programClass)
{
// Change the references of the constant pool.
programClass.constantPoolEntriesAccept(this);
// Change the references of the class members.
programClass.fieldsAccept(this);
programClass.methodsAccept(this);
// Change the references of the attributes.
programClass.attributesAccept(this);
// Is the class itself being retargeted?
Clazz targetClass = ClassMerger.getTargetClass(programClass);
if (targetClass != null)
{
// Restore the class name. We have to add a new class entry
// to avoid an existing entry with the same name being reused. The
// names have to be fixed later, based on their referenced classes.
programClass.u2thisClass =
addNewClassConstant(programClass,
programClass.getName(),
programClass);
// This class will loose all its interfaces.
programClass.u2interfacesCount = 0;
// This class will loose all its subclasses.
programClass.subClasses = null;
}
else
{
// Remove interface classes that are pointing to this class.
int newInterfacesCount = 0;
for (int index = 0; index < programClass.u2interfacesCount; index++)
{
Clazz interfaceClass = programClass.getInterface(index);
if (!programClass.equals(interfaceClass))
{
programClass.u2interfaces[newInterfacesCount++] =
programClass.u2interfaces[index];
}
}
programClass.u2interfacesCount = newInterfacesCount;
// Update the subclasses of the superclass and interfaces of the
// target class.
ConstantVisitor subclassAdder =
new ReferencedClassVisitor(
new SubclassFilter(programClass,
new SubclassAdder(programClass)));
programClass.superClassConstantAccept(subclassAdder);
programClass.interfaceConstantsAccept(subclassAdder);
// TODO: Maybe restore private method references.
}
}
public void visitLibraryClass(LibraryClass libraryClass)
{
// Change the references of the class members.
libraryClass.fieldsAccept(this);
libraryClass.methodsAccept(this);
}
// Implementations for MemberVisitor.
public void visitProgramField(ProgramClass programClass, ProgramField programField)
{
// Change the referenced class.
programField.referencedClass =
updateReferencedClass(programField.referencedClass);
// Change the references of the attributes.
programField.attributesAccept(programClass, this);
}
public void visitProgramMethod(ProgramClass programClass, ProgramMethod programMethod)
{
// Change the referenced classes.
updateReferencedClasses(programMethod.referencedClasses);
// Change the references of the attributes.
programMethod.attributesAccept(programClass, this);
}
public void visitLibraryField(LibraryClass libraryClass, LibraryField libraryField)
{
// Change the referenced class.
libraryField.referencedClass =
updateReferencedClass(libraryField.referencedClass);
}
public void visitLibraryMethod(LibraryClass libraryClass, LibraryMethod libraryMethod)
{
// Change the referenced classes.
updateReferencedClasses(libraryMethod.referencedClasses);
}
// Implementations for ConstantVisitor.
public void visitAnyConstant(Clazz clazz, Constant constant) {}
public void visitStringConstant(Clazz clazz, StringConstant stringConstant)
{
// Does the string refer to a class, due to a Class.forName construct?
Clazz referencedClass = stringConstant.referencedClass;
Clazz newReferencedClass = updateReferencedClass(referencedClass);
if (referencedClass != newReferencedClass)
{
// Change the referenced class.
stringConstant.referencedClass = newReferencedClass;
// Change the referenced class member, if applicable.
stringConstant.referencedMember =
updateReferencedMember(stringConstant.referencedMember,
stringConstant.getString(clazz),
null,
newReferencedClass);
}
}
public void visitAnyRefConstant(Clazz clazz, RefConstant refConstant)
{
Clazz referencedClass = refConstant.referencedClass;
Clazz newReferencedClass = updateReferencedClass(referencedClass);
if (referencedClass != newReferencedClass)
{
if (DEBUG)
{
System.out.println("TargetClassChanger:");
System.out.println(" ["+clazz.getName()+"] changing reference from ["+refConstant.referencedClass+"."+refConstant.referencedMember.getName(refConstant.referencedClass)+refConstant.referencedMember.getDescriptor(refConstant.referencedClass)+"]");
}
// Change the referenced class.
refConstant.referencedClass = newReferencedClass;
// Change the referenced class member.
refConstant.referencedMember =
updateReferencedMember(refConstant.referencedMember,
refConstant.getName(clazz),
refConstant.getType(clazz),
newReferencedClass);
if (DEBUG)
{
System.out.println(" ["+clazz.getName()+"] to ["+refConstant.referencedClass+"."+refConstant.referencedMember.getName(refConstant.referencedClass)+refConstant.referencedMember.getDescriptor(refConstant.referencedClass)+"]");
}
}
}
public void visitClassConstant(Clazz clazz, ClassConstant classConstant)
{
// Change the referenced class.
classConstant.referencedClass =
updateReferencedClass(classConstant.referencedClass);
}
// Implementations for AttributeVisitor.
public void visitAnyAttribute(Clazz clazz, Attribute attribute) {}
public void visitCodeAttribute(Clazz clazz, Method method, CodeAttribute codeAttribute)
{
// Change the references of the attributes.
codeAttribute.attributesAccept(clazz, method, this);
}
public void visitLocalVariableTableAttribute(Clazz clazz, Method method, CodeAttribute codeAttribute, LocalVariableTableAttribute localVariableTableAttribute)
{
// Change the references of the local variables.
localVariableTableAttribute.localVariablesAccept(clazz, method, codeAttribute, this);
}
public void visitLocalVariableTypeTableAttribute(Clazz clazz, Method method, CodeAttribute codeAttribute, LocalVariableTypeTableAttribute localVariableTypeTableAttribute)
{
// Change the references of the local variables.
localVariableTypeTableAttribute.localVariablesAccept(clazz, method, codeAttribute, this);
}
public void visitSignatureAttribute(Clazz clazz, SignatureAttribute signatureAttribute)
{
// Change the referenced classes.
updateReferencedClasses(signatureAttribute.referencedClasses);
}
public void visitAnyAnnotationsAttribute(Clazz clazz, AnnotationsAttribute annotationsAttribute)
{
// Change the references of the annotations.
annotationsAttribute.annotationsAccept(clazz, this);
}
public void visitAnyParameterAnnotationsAttribute(Clazz clazz, Method method, ParameterAnnotationsAttribute parameterAnnotationsAttribute)
{
// Change the references of the annotations.
parameterAnnotationsAttribute.annotationsAccept(clazz, method, this);
}
public void visitAnnotationDefaultAttribute(Clazz clazz, Method method, AnnotationDefaultAttribute annotationDefaultAttribute)
{
// Change the references of the annotation.
annotationDefaultAttribute.defaultValueAccept(clazz, this);
}
// Implementations for LocalVariableInfoVisitor.
public void visitLocalVariableInfo(Clazz clazz, Method method, CodeAttribute codeAttribute, LocalVariableInfo localVariableInfo)
{
// Change the referenced class.
localVariableInfo.referencedClass =
updateReferencedClass(localVariableInfo.referencedClass);
}
// Implementations for LocalVariableTypeInfoVisitor.
public void visitLocalVariableTypeInfo(Clazz clazz, Method method, CodeAttribute codeAttribute, LocalVariableTypeInfo localVariableTypeInfo)
{
// Change the referenced classes.
updateReferencedClasses(localVariableTypeInfo.referencedClasses);
}
// Implementations for AnnotationVisitor.
public void visitAnnotation(Clazz clazz, Annotation annotation)
{
// Change the referenced classes.
updateReferencedClasses(annotation.referencedClasses);
// Change the references of the element values.
annotation.elementValuesAccept(clazz, this);
}
// Implementations for ElementValueVisitor.
public void visitAnyElementValue(Clazz clazz, Annotation annotation, ElementValue elementValue)
{
Clazz referencedClass = elementValue.referencedClass;
Clazz newReferencedClass = updateReferencedClass(referencedClass);
if (referencedClass != newReferencedClass)
{
// Change the referenced annotation class.
elementValue.referencedClass = newReferencedClass;
// Change the referenced method.
elementValue.referencedMethod =
(Method)updateReferencedMember(elementValue.referencedMethod,
elementValue.getMethodName(clazz),
null,
newReferencedClass);
}
}
public void visitConstantElementValue(Clazz clazz, Annotation annotation, ConstantElementValue constantElementValue)
{
// Change the referenced annotation class and method.
visitAnyElementValue(clazz, annotation, constantElementValue);
}
public void visitEnumConstantElementValue(Clazz clazz, Annotation annotation, EnumConstantElementValue enumConstantElementValue)
{
// Change the referenced annotation class and method.
visitAnyElementValue(clazz, annotation, enumConstantElementValue);
// Change the referenced classes.
updateReferencedClasses(enumConstantElementValue.referencedClasses);
}
public void visitClassElementValue(Clazz clazz, Annotation annotation, ClassElementValue classElementValue)
{
// Change the referenced annotation class and method.
visitAnyElementValue(clazz, annotation, classElementValue);
// Change the referenced classes.
updateReferencedClasses(classElementValue.referencedClasses);
}
public void visitAnnotationElementValue(Clazz clazz, Annotation annotation, AnnotationElementValue annotationElementValue)
{
// Change the referenced annotation class and method.
visitAnyElementValue(clazz, annotation, annotationElementValue);
// Change the references of the annotation.
annotationElementValue.annotationAccept(clazz, this);
}
public void visitArrayElementValue(Clazz clazz, Annotation annotation, ArrayElementValue arrayElementValue)
{
// Change the referenced annotation class and method.
visitAnyElementValue(clazz, annotation, arrayElementValue);
// Change the references of the element values.
arrayElementValue.elementValuesAccept(clazz, annotation, this);
}
// Small utility methods.
/**
* Updates the retargeted classes in the given array of classes.
*/
private void updateReferencedClasses(Clazz[] referencedClasses)
{
if (referencedClasses == null)
{
return;
}
for (int index = 0; index < referencedClasses.length; index++)
{
referencedClasses[index] =
updateReferencedClass(referencedClasses[index]);
}
}
/**
* Returns the retargeted class of the given class.
*/
private Clazz updateReferencedClass(Clazz referencedClass)
{
if (referencedClass == null)
{
return null;
}
Clazz targetClazz = ClassMerger.getTargetClass(referencedClass);
return targetClazz != null ?
targetClazz :
referencedClass;
}
/**
* Returns the retargeted class member of the given class member.
*/
private Member updateReferencedMember(Member referencedMember,
String name,
String type,
Clazz newReferencedClass)
{
if (referencedMember == null)
{
return null;
}
return referencedMember instanceof Field ?
(Member)newReferencedClass.findField(name, type) :
(Member)newReferencedClass.findMethod(name, type);
}
/**
* Explicitly adds a new class constant for the given class in the given
* program class.
*/
private int addNewClassConstant(ProgramClass programClass,
String className,
Clazz referencedClass)
{
ConstantPoolEditor constantPoolEditor =
new ConstantPoolEditor(programClass);
int nameIndex =
constantPoolEditor.addUtf8Constant(className);
int classConstantIndex =
constantPoolEditor.addConstant(new ClassConstant(nameIndex,
referencedClass));
return classConstantIndex;
}
}