catchexceptionmarker.java

ProGuard 是一个免费的 Java类文件的压缩

/*
 * ProGuard -- shrinking, optimization, obfuscation, and preverification
 *             of Java bytecode.
 *
 * Copyright (c) 2002-2007 Eric Lafortune ([e-mail])
 *
 * This library 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 library 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 Lesser General Public License
 * for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this library; if not, write to the Free Software Foundation,
 * Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */
package proguard.optimize.info;

import proguard.classfile.util.SimplifiedVisitor;
import proguard.classfile.attribute.visitor.AttributeVisitor;
import proguard.classfile.attribute.*;
import proguard.classfile.*;

/**
 * This AttributeVisitor marks all methods that catch exceptions.
 *
 * @author Eric Lafortune
 */
public class CatchExceptionMarker
extends      SimplifiedVisitor
implements   AttributeVisitor
{
    // Implementations for AttributeVisitor.

    public void visitAnyAttribute(Clazz clazz, Attribute attribute) {}


    public void visitCodeAttribute(Clazz clazz, Method method, CodeAttribute codeAttribute)
    {
        if (codeAttribute.u2exceptionTableLength > 0)
        {
            markCatchException(method);
        }
    }


    // Small utility methods.

    private static void markCatchException(Method method)
    {
        MethodOptimizationInfo info = MethodOptimizationInfo.getMethodOptimizationInfo(method);
        if (info != null)
        {
            info.setCatchesExceptions();
        }
    }


    public static boolean catchesExceptions(Method method)
    {
        MethodOptimizationInfo info = MethodOptimizationInfo.getMethodOptimizationInfo(method);
        return info == null ||
               info.catchesExceptions();
    }
}