proguard.classfile.editor.ClassEditor Maven / Gradle / Ivy
/*
* ProGuard -- shrinking, optimization, obfuscation, and preverification
* of Java bytecode.
*
* Copyright (c) 2002-2018 GuardSquare NV
*
* 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.editor;
import proguard.classfile.*;
/**
* This class can add interfaces and class members to a given class.
* Elements to be added must be filled out beforehand, including their
* references to the constant pool.
*
* @author Eric Lafortune
*/
public class ClassEditor
{
private static final boolean DEBUG = false;
private ProgramClass targetClass;
/**
* Creates a new ClassEditor that will edit elements in the given
* target class.
*/
public ClassEditor(ProgramClass targetClass)
{
this.targetClass = targetClass;
}
/**
* Adds the given interface.
*/
public void addInterface(int interfaceConstantIndex)
{
int interfacesCount = targetClass.u2interfacesCount;
int[] interfaces = targetClass.u2interfaces;
// Make sure there is enough space for the new interface.
if (interfaces.length <= interfacesCount)
{
targetClass.u2interfaces = new int[interfacesCount+1];
System.arraycopy(interfaces, 0,
targetClass.u2interfaces, 0,
interfacesCount);
interfaces = targetClass.u2interfaces;
}
if (DEBUG)
{
System.out.println(targetClass.getName()+": adding interface ["+targetClass.getClassName(interfaceConstantIndex)+"]");
}
// Add the interface.
interfaces[targetClass.u2interfacesCount++] = interfaceConstantIndex;
}
/**
* Removes the given interface.
*/
public void removeInterface(int interfaceConstantIndex)
{
int interfacesCount = targetClass.u2interfacesCount;
int[] interfaces = targetClass.u2interfaces;
int interfaceIndex = findInterfaceIndex(interfaceConstantIndex);
// Shift the interface entries.
System.arraycopy(interfaces, interfaceIndex+1,
interfaces, interfaceIndex,
interfacesCount - interfaceIndex - 1);
// Clear the last entry.
interfaces[--targetClass.u2interfacesCount] = 0;
}
/**
* Finds the index of the given interface in the target class.
*/
private int findInterfaceIndex(int interfaceConstantIndex)
{
int interfacesCount = targetClass.u2interfacesCount;
int[] interfaces = targetClass.u2interfaces;
for (int index = 0; index < interfacesCount; index++)
{
if (interfaces[index] == interfaceConstantIndex)
{
return index;
}
}
return interfacesCount;
}
/**
* Adds the given field.
*/
public void addField(Field field)
{
int fieldsCount = targetClass.u2fieldsCount;
Field[] fields = targetClass.fields;
// Make sure there is enough space for the new field.
if (fields.length <= fieldsCount)
{
targetClass.fields = new ProgramField[fieldsCount+1];
System.arraycopy(fields, 0,
targetClass.fields, 0,
fieldsCount);
fields = targetClass.fields;
}
if (DEBUG)
{
System.out.println(targetClass.getName()+": adding field ["+field.getName(targetClass)+" "+field.getDescriptor(targetClass)+"]");
}
// Add the field.
fields[targetClass.u2fieldsCount++] = field;
}
/**
* Removes the given field. Note that removing a field that is still being
* referenced can cause unpredictable effects.
*/
public void removeField(Field field)
{
int fieldsCount = targetClass.u2fieldsCount;
Field[] fields = targetClass.fields;
int fieldIndex = findFieldIndex(field);
// Shift the field entries.
System.arraycopy(fields, fieldIndex+1,
fields, fieldIndex,
fieldsCount - fieldIndex - 1);
// Clear the last entry.
fields[--targetClass.u2fieldsCount] = null;
}
/**
* Finds the index of the given field in the target class.
*/
private int findFieldIndex(Field field)
{
int fieldsCount = targetClass.u2fieldsCount;
Field[] fields = targetClass.fields;
for (int index = 0; index < fieldsCount; index++)
{
if (fields[index].equals(field))
{
return index;
}
}
return fieldsCount;
}
/**
* Adds the given method.
*/
public void addMethod(Method method)
{
int methodsCount = targetClass.u2methodsCount;
Method[] methods = targetClass.methods;
// Make sure there is enough space for the new method.
if (methods.length <= methodsCount)
{
targetClass.methods = new ProgramMethod[methodsCount+1];
System.arraycopy(methods, 0,
targetClass.methods, 0,
methodsCount);
methods = targetClass.methods;
}
if (DEBUG)
{
System.out.println(targetClass.getName()+": adding method ["+method.getName(targetClass)+method.getDescriptor(targetClass)+"]");
}
// Add the method.
methods[targetClass.u2methodsCount++] = method;
}
/**
* Removes the given method. Note that removing a method that is still being
* referenced can cause unpredictable effects.
*/
public void removeMethod(Method method)
{
int methodsCount = targetClass.u2methodsCount;
Method[] methods = targetClass.methods;
int methodIndex = findMethodIndex(method);
// Shift the method entries.
System.arraycopy(methods, methodIndex+1,
methods, methodIndex,
methodsCount - methodIndex - 1);
// Clear the last entry.
methods[--targetClass.u2methodsCount] = null;
}
/**
* Finds the index of the given method in the target class.
*/
private int findMethodIndex(Method method)
{
int methodsCount = targetClass.u2methodsCount;
Method[] methods = targetClass.methods;
for (int index = 0; index < methodsCount; index++)
{
if (methods[index].equals(method))
{
return index;
}
}
return methodsCount;
}
}
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