proguard.shrink.UsagePrinter Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of proguard
ProGuard is a free Java class file shrinker, optimizer, and obfuscator. It removes unused classes, fields, methods, and attributes. It then optimizes the bytecode. It then renames the remaining classes, fields, and methods using short meaningless names. Finally, it preverifies the processed code for Java 6 or for Java Micro Edition.
The newest version!
/*
 * ProGuard -- shrinking, optimization, obfuscation, and preverification
 *             of Java bytecode.
 *
 * Copyright (c) 2002-2009 Eric Lafortune ([email protected])
 *
 * 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.shrink;

import proguard.classfile.*;
import proguard.classfile.util.*;
import proguard.classfile.visitor.*;

import java.io.PrintStream;


/**
 * This ClassVisitor prints out the classes and class members that have been
 * marked as being used (or not used).
 *
 * @see UsageMarker
 *
 * @author Eric Lafortune
 */
public class UsagePrinter
extends      SimplifiedVisitor
implements   ClassVisitor,
             MemberVisitor
{
    private final UsageMarker usageMarker;
    private final boolean     printUnusedItems;
    private final PrintStream ps;

    // A field to remember the class name, if a header is needed for class members.
    private String      className;


    /**
     * Creates a new UsagePrinter that prints to System.out.
     * @param usageMarker      the usage marker that was used to mark the
     *                         classes and class members.
     * @param printUnusedItems a flag that indicates whether only unused items
     *                         should be printed, or alternatively, only used
     *                         items.
     */
    public UsagePrinter(UsageMarker usageMarker,
                        boolean     printUnusedItems)
    {
        this(usageMarker, printUnusedItems, System.out);
    }


    /**
     * Creates a new UsagePrinter that prints to the given stream.
     * @param usageMarker      the usage marker that was used to mark the
     *                         classes and class members.
     * @param printUnusedItems a flag that indicates whether only unused items
     *                         should be printed, or alternatively, only used
     *                         items.
     * @param printStream      the stream to which to print.
     */
    public UsagePrinter(UsageMarker usageMarker,
                        boolean     printUnusedItems,
                        PrintStream printStream)
    {
        this.usageMarker      = usageMarker;
        this.printUnusedItems = printUnusedItems;
        this.ps               = printStream;
    }


    // Implementations for ClassVisitor.

    public void visitProgramClass(ProgramClass programClass)
    {
        if (usageMarker.isUsed(programClass))
        {
            if (printUnusedItems)
            {
                className = programClass.getName();

                programClass.fieldsAccept(this);
                programClass.methodsAccept(this);

                className = null;
            }
            else
            {
                ps.println(ClassUtil.externalClassName(programClass.getName()));
            }
        }
        else
        {
            if (printUnusedItems)
            {
                ps.println(ClassUtil.externalClassName(programClass.getName()));
            }
        }
    }


    // Implementations for MemberVisitor.

    public void visitProgramField(ProgramClass programClass, ProgramField programField)
    {
        if (usageMarker.isUsed(programField) ^ printUnusedItems)
        {
            printClassNameHeader();

            ps.println("    " +
                       lineNumberRange(programClass, programField) +
                       ClassUtil.externalFullFieldDescription(
                           programField.getAccessFlags(),
                           programField.getName(programClass),
                           programField.getDescriptor(programClass)));
        }
    }


    public void visitProgramMethod(ProgramClass programClass, ProgramMethod programMethod)
    {
        if (usageMarker.isUsed(programMethod) ^ printUnusedItems)
        {
            printClassNameHeader();

            ps.println("    " +
                       lineNumberRange(programClass, programMethod) +
                       ClassUtil.externalFullMethodDescription(
                           programClass.getName(),
                           programMethod.getAccessFlags(),
                           programMethod.getName(programClass),
                           programMethod.getDescriptor(programClass)));
        }
    }


    // Small utility methods.

    /**
     * Prints the class name field. The field is then cleared, so it is not
     * printed again.
     */
    private void printClassNameHeader()
    {
        if (className != null)
        {
            ps.println(ClassUtil.externalClassName(className) + ":");
            className = null;
        }
    }


    /**
     * Returns the line number range of the given class member, followed by a
     * colon, or just an empty String if no range is available.
     */
    private static String lineNumberRange(ProgramClass programClass, ProgramMember programMember)
    {
        String range = programMember.getLineNumberRange(programClass);
        return range != null ?
            (range + ":") :
            "";
    }
}