proguard.classfile.editor.BootstrapMethodsAttributeEditor Maven / Gradle / Ivy

/*
 * ProGuard -- shrinking, optimization, obfuscation, and preverification
 *             of Java bytecode.
 *
 * Copyright (c) 2002-2019 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.attribute.*;
import proguard.util.ArrayUtil;

/**
 * This class can add/remove bootstrap methods to/from a given bootstrap methods
 * attribute. Bootstrap methods to be added must have been filled out beforehand.
 *
 * @author Eric Lafortune
 */
public class BootstrapMethodsAttributeEditor
{
    private BootstrapMethodsAttribute targetBootstrapMethodsAttribute;


    /**
     * Creates a new BootstrapMethodsAttributeEditor that will edit bootstrap
     * methods in the given bootstrap methods attribute.
     */
    public BootstrapMethodsAttributeEditor(BootstrapMethodsAttribute targetBootstrapMethodsAttribute)
    {
        this.targetBootstrapMethodsAttribute = targetBootstrapMethodsAttribute;
    }


    /**
     * Adds a given bootstrap method to the bootstrap methods attribute.
     * @return the index of the bootstrap method.
     */
    public int addBootstrapMethodInfo(BootstrapMethodInfo bootstrapMethodInfo)
    {
        targetBootstrapMethodsAttribute.bootstrapMethods =
            ArrayUtil.add(targetBootstrapMethodsAttribute.bootstrapMethods,
                          targetBootstrapMethodsAttribute.u2bootstrapMethodsCount,
                          bootstrapMethodInfo);

        return targetBootstrapMethodsAttribute.u2bootstrapMethodsCount++;
    }


    /**
     * Removes the given bootstrap method from the bootstrap method attribute.
     */
    public void removeBootstrapMethodInfo(BootstrapMethodInfo bootstrapMethodInfo)
    {
        ArrayUtil.remove(targetBootstrapMethodsAttribute.bootstrapMethods,
                         targetBootstrapMethodsAttribute.u2bootstrapMethodsCount--,
                         findBootstrapMethodInfoIndex(bootstrapMethodInfo));
    }


    /**
     * Finds the index of the given bootstrap method info in the target attribute.
     */
    private int findBootstrapMethodInfoIndex(BootstrapMethodInfo bootstrapMethodInfo)
    {
        int                   methodsCount = targetBootstrapMethodsAttribute.u2bootstrapMethodsCount;
        BootstrapMethodInfo[] methodInfos  = targetBootstrapMethodsAttribute.bootstrapMethods;

        for (int index = 0; index < methodsCount; index++)
        {
            if (methodInfos[index].equals(bootstrapMethodInfo))
            {
                return index;
            }
        }

        return methodsCount;
    }
}