/*
 * 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.optimize.info;

import proguard.classfile.*;
import proguard.classfile.attribute.CodeAttribute;
import proguard.classfile.constant.ClassConstant;
import proguard.classfile.constant.visitor.ConstantVisitor;
import proguard.classfile.instruction.*;
import proguard.classfile.instruction.visitor.InstructionVisitor;
import proguard.classfile.util.SimplifiedVisitor;
import proguard.classfile.visitor.ClassVisitor;

/**
 * This InstructionVisitor marks all classes that are used in an 'instanceof'
 * test by any of the instructions that it visits.
 *
 * @author Eric Lafortune
 */
public class InstanceofClassMarker
extends      SimplifiedVisitor
implements   InstructionVisitor,
             ConstantVisitor,
             ClassVisitor
{
    // Implementations for InstructionVisitor.

    public void visitAnyInstruction(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset, Instruction instruction) {}


    public void visitConstantInstruction(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset, ConstantInstruction constantInstruction)
    {
        if (constantInstruction.opcode == InstructionConstants.OP_INSTANCEOF)
        {
            clazz.constantPoolEntryAccept(constantInstruction.constantIndex, this);
        }
    }


    // Implementations for ConstantVisitor.

    public void visitClassConstant(Clazz clazz, ClassConstant classConstant)
    {
        classConstant.referencedClassAccept(this);
    }


    // Implementations for ClassVisitor.

    public void visitLibraryClass(LibraryClass libraryClass) {}

    public void visitProgramClass(ProgramClass programClass)
    {
        setInstanceofed(programClass);
    }


    // Small utility methods.

    private static void setInstanceofed(Clazz clazz)
    {
        ClassOptimizationInfo info = ClassOptimizationInfo.getClassOptimizationInfo(clazz);
        if (info != null)
        {
            info.setInstanceofed();
        }
    }


    public static boolean isInstanceofed(Clazz clazz)
    {
        ClassOptimizationInfo info = ClassOptimizationInfo.getClassOptimizationInfo(clazz);
        return info == null || info.isInstanceofed();
    }
}