src/proguard/classfile/editor/MemberAdder.java

/*
 * ProGuard -- shrinking, optimization, obfuscation, and preverification
 *             of Java bytecode.
 *
 * Copyright (c) 2002-2009 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.editor;

import proguard.classfile.*;
import proguard.classfile.attribute.Attribute;
import proguard.classfile.util.SimplifiedVisitor;
import proguard.classfile.visitor.MemberVisitor;

/**
 * This ConstantVisitor adds all class members that it visits to the given
 * target class.
 *
 * @author Eric Lafortune
 */
public class MemberAdder
extends      SimplifiedVisitor
implements   MemberVisitor
{
    //*
    private static final boolean DEBUG = false;
    /*/
    private static       boolean DEBUG = true;
    //*/


    private static final Attribute[] EMPTY_ATTRIBUTES = new Attribute[0];


    private final ProgramClass targetClass;
//    private final boolean      addFields;

    private final ConstantAdder      constantAdder;
    private final ClassEditor        classEditor;
    private final ConstantPoolEditor constantPoolEditor;


    /**
     * Creates a new MemberAdder that will copy methods into the given target
     * class.
     * @param targetClass the class to which all visited class members will be
     *                    added.
     */
//     * @param addFields   specifies whether fields should be added, or fused
//     *                    with the present fields.
    public MemberAdder(ProgramClass targetClass)//),
//                       boolean      addFields)
    {
        this.targetClass = targetClass;
//        this.addFields   = addFields;

        constantAdder      = new ConstantAdder(targetClass);
        classEditor        = new ClassEditor(targetClass);
        constantPoolEditor = new ConstantPoolEditor(targetClass);
    }


    // Implementations for MemberVisitor.

    public void visitProgramField(ProgramClass programClass, ProgramField programField)
    {
        String name        = programField.getName(programClass);
        String descriptor  = programField.getDescriptor(programClass);
        int    accessFlags = programField.getAccessFlags();

        // Does the target class already have such a field?
        ProgramField targetField = (ProgramField)targetClass.findField(name, descriptor);
        if (targetField != null)
        {
            // Is the field private or static?
            int targetAccessFlags = targetField.getAccessFlags();
            if ((targetAccessFlags &
                 (ClassConstants.INTERNAL_ACC_PRIVATE |
                  ClassConstants.INTERNAL_ACC_STATIC)) != 0)
            {
                if (DEBUG)
                {
                    System.out.println("MemberAdder: renaming field ["+targetClass+"."+targetField.getName(targetClass)+" "+targetField.getDescriptor(targetClass)+"]");
                }

                // Rename the private or static field.
                targetField.u2nameIndex =
                    constantPoolEditor.addUtf8Constant(newUniqueMemberName(name, targetClass.getName()));
            }
//            else
//            {
//                // Keep the non-private and non-static field, but update its
//                // contents, in order to keep any references to it valid.
//                if (DEBUG)
//                {
//                    System.out.println("MemberAdder: updating field ["+programClass+"."+programField.getName(programClass)+" "+programField.getDescriptor(programClass)+"] into ["+targetClass.getName()+"]");
//                }
//
//                // Combine the access flags.
//                targetField.u2accessFlags = accessFlags | targetAccessFlags;
//
//                // Add and replace any attributes.
//                programField.attributesAccept(programClass,
//                                              new AttributeAdder(targetClass,
//                                                                 targetField,
//                                                                 true));
//
//                // Don't add a new field.
//                return;
//            }
        }

        if (DEBUG)
        {
            System.out.println("MemberAdder: copying field ["+programClass+"."+programField.getName(programClass)+" "+programField.getDescriptor(programClass)+"] into ["+targetClass.getName()+"]");
        }

        // Create a copy of the field.
        ProgramField newProgramField =
            new ProgramField(accessFlags,
                             constantAdder.addConstant(programClass, programField.u2nameIndex),
                             constantAdder.addConstant(programClass, programField.u2descriptorIndex),
                             0,
                             programField.u2attributesCount > 0 ?
                                 new Attribute[programField.u2attributesCount] :
                                 EMPTY_ATTRIBUTES,
                             programField.referencedClass);

        // Link to its visitor info.
        newProgramField.setVisitorInfo(programField);

        // Copy its attributes.
        programField.attributesAccept(programClass,
                                      new AttributeAdder(targetClass,
                                                         newProgramField,
                                                         false));

        // Add the completed field.
        classEditor.addField(newProgramField);
    }


    public void visitProgramMethod(ProgramClass programClass, ProgramMethod programMethod)
    {
        String name        = programMethod.getName(programClass);
        String descriptor  = programMethod.getDescriptor(programClass);
        int    accessFlags = programMethod.getAccessFlags();

        // Does the target class already have such a method?
        ProgramMethod targetMethod = (ProgramMethod)targetClass.findMethod(name, descriptor);
        if (targetMethod != null)
        {
            // is this source method abstract?
            if ((accessFlags & ClassConstants.INTERNAL_ACC_ABSTRACT) != 0)
            {
                // Keep the target method.
                if (DEBUG)
                {
                    System.out.println("MemberAdder: skipping abstract method ["+programClass.getName()+"."+programMethod.getName(programClass)+programMethod.getDescriptor(programClass)+"] into ["+targetClass.getName()+"]");
                }

                // Don't add a new method.
                return;
            }

            // Is the target method abstract?
            int targetAccessFlags = targetMethod.getAccessFlags();
            if ((targetAccessFlags & ClassConstants.INTERNAL_ACC_ABSTRACT) != 0)
            {
                // Keep the abstract method, but update its contents, in order
                // to keep any references to it valid.
                if (DEBUG)
                {
                    System.out.println("MemberAdder: updating method ["+programClass.getName()+"."+programMethod.getName(programClass)+programMethod.getDescriptor(programClass)+"] into ["+targetClass.getName()+"]");
                }

                // Replace the access flags.
                targetMethod.u2accessFlags =
                    accessFlags & ~ClassConstants.INTERNAL_ACC_FINAL;

                // Add and replace the attributes.
                programMethod.attributesAccept(programClass,
                                               new AttributeAdder(targetClass,
                                                                  targetMethod,
                                                                  true));

                // Don't add a new method.
                return;
            }

            if (DEBUG)
            {
                System.out.println("MemberAdder: renaming method ["+targetClass.getName()+"."+targetMethod.getName(targetClass)+targetMethod.getDescriptor(targetClass)+"]");
            }

            // Rename the private (non-abstract) or static method.
            targetMethod.u2nameIndex =
                constantPoolEditor.addUtf8Constant(newUniqueMemberName(name, descriptor));
        }

        if (DEBUG)
        {
            System.out.println("MemberAdder: copying method ["+programClass.getName()+"."+programMethod.getName(programClass)+programMethod.getDescriptor(programClass)+"] into ["+targetClass.getName()+"]");
        }

        // Create a copy of the method.
        ProgramMethod newProgramMethod =
            new ProgramMethod(accessFlags & ~ClassConstants.INTERNAL_ACC_FINAL,
                              constantAdder.addConstant(programClass, programMethod.u2nameIndex),
                              constantAdder.addConstant(programClass, programMethod.u2descriptorIndex),
                              0,
                              programMethod.u2attributesCount > 0 ?
                                  new Attribute[programMethod.u2attributesCount] :
                                  EMPTY_ATTRIBUTES,
                              programMethod.referencedClasses != null ?
                                  (Clazz[])programMethod.referencedClasses.clone() :
                                  null);

        // Link to its visitor info.
        newProgramMethod.setVisitorInfo(programMethod);

        // Copy its attributes.
        programMethod.attributesAccept(programClass,
                                       new AttributeAdder(targetClass,
                                                          newProgramMethod,
                                                          false));

        // Add the completed method.
        classEditor.addMethod(newProgramMethod);
    }


    // Small utility methods.

    /**
     * Returns a unique class member name, based on the given name and descriptor.
     */
    private String newUniqueMemberName(String name, String descriptor)
    {
        return name.equals(ClassConstants.INTERNAL_METHOD_NAME_INIT) ?
            ClassConstants.INTERNAL_METHOD_NAME_INIT :
            name + ClassConstants.SPECIAL_MEMBER_SEPARATOR + Long.toHexString(Math.abs((descriptor).hashCode()));
    }
}