programclasswriter.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 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.io;

import proguard.classfile.*;
import proguard.classfile.attribute.*;
import proguard.classfile.attribute.annotation.*;
import proguard.classfile.attribute.annotation.visitor.*;
import proguard.classfile.attribute.preverification.*;
import proguard.classfile.attribute.preverification.visitor.*;
import proguard.classfile.attribute.visitor.*;
import proguard.classfile.constant.*;
import proguard.classfile.constant.visitor.ConstantVisitor;
import proguard.classfile.util.*;
import proguard.classfile.visitor.*;

import java.io.*;

/**
 * This ClassVisitor writes out the ProgramClass objects that it visits to the
 * given DataOutput object.
 *
 * @author Eric Lafortune
 */
public class ProgramClassWriter
extends      SimplifiedVisitor
implements   ClassVisitor,
             MemberVisitor,
             ConstantVisitor,
             AttributeVisitor
{
    private RuntimeDataOutput dataOutput;

    private ConstantBodyWriter         constantBodyWriter         = new ConstantBodyWriter();
    private AttributeBodyWriter        attributeBodyWriter        = new AttributeBodyWriter();
    private StackMapFrameBodyWriter    stackMapFrameBodyWriter    = new StackMapFrameBodyWriter();
    private VerificationTypeBodyWriter verificationTypeBodyWriter = new VerificationTypeBodyWriter();
    private ElementValueBodyWriter     elementValueBodyWriter     = new ElementValueBodyWriter();


    /**
     * Creates a new ProgramClassWriter for reading from the given DataOutput.
     */
    public ProgramClassWriter(DataOutput dataOutput)
    {
        this.dataOutput = new RuntimeDataOutput(dataOutput);
    }


    // Implementations for ClassVisitor.

    public void visitProgramClass(ProgramClass programClass)
    {
        // Write the magic number.
        dataOutput.writeInt(programClass.u4magic);

        // Write the version numbers.
        dataOutput.writeShort(ClassUtil.internalMinorClassVersion(programClass.u4version));
        dataOutput.writeShort(ClassUtil.internalMajorClassVersion(programClass.u4version));

        // Write the constant pool.
        dataOutput.writeShort(programClass.u2constantPoolCount);

        programClass.constantPoolEntriesAccept(this);

        // Write the general class information.
        dataOutput.writeShort(programClass.u2accessFlags);
        dataOutput.writeShort(programClass.u2thisClass);
        dataOutput.writeShort(programClass.u2superClass);

        // Write the interfaces.
        dataOutput.writeShort(programClass.u2interfacesCount);

        for (int index = 0; index < programClass.u2interfacesCount; index++)
        {
            dataOutput.writeShort(programClass.u2interfaces[index]);
        }

        // Write the fields.
        dataOutput.writeShort(programClass.u2fieldsCount);

        programClass.fieldsAccept(this);

        // Write the methods.
        dataOutput.writeShort(programClass.u2methodsCount);

        programClass.methodsAccept(this);

        // Write the class attributes.
        dataOutput.writeShort(programClass.u2attributesCount);

        programClass.attributesAccept(this);
    }


    public void visitLibraryClass(LibraryClass libraryClass)
    {
    }


    // Implementations for MemberVisitor.

    public void visitProgramField(ProgramClass programClass, ProgramField programField)
    {
        // Write the general field information.
        dataOutput.writeShort(programField.u2accessFlags);
        dataOutput.writeShort(programField.u2nameIndex);
        dataOutput.writeShort(programField.u2descriptorIndex);

        // Write the field attributes.
        dataOutput.writeShort(programField.u2attributesCount);

        programField.attributesAccept(programClass, this);
    }


    public void visitProgramMethod(ProgramClass programClass, ProgramMethod programMethod)
    {
        // Write the general method information.
        dataOutput.writeShort(programMethod.u2accessFlags);
        dataOutput.writeShort(programMethod.u2nameIndex);
        dataOutput.writeShort(programMethod.u2descriptorIndex);

        // Write the method attributes.
        dataOutput.writeShort(programMethod.u2attributesCount);

        programMethod.attributesAccept(programClass, this);
    }


    public void visitLibraryMember(LibraryClass libraryClass, LibraryMember libraryMember)
    {
    }


    // Implementations for ConstantVisitor.

    public void visitAnyConstant(Clazz clazz, Constant constant)
    {
        // Write the tag.
        dataOutput.writeByte(constant.getTag());

        // Write the actual body.
        constant.accept(clazz, constantBodyWriter);
    }


    private class ConstantBodyWriter
    extends       SimplifiedVisitor
    implements    ConstantVisitor
    {
        // Implementations for ConstantVisitor.

        public void visitIntegerConstant(Clazz clazz, IntegerConstant integerConstant)
        {
            dataOutput.writeInt(integerConstant.u4value);
        }


        public void visitLongConstant(Clazz clazz, LongConstant longConstant)
        {
            dataOutput.writeLong(longConstant.u8value);
        }


        public void visitFloatConstant(Clazz clazz, FloatConstant floatConstant)
        {
            dataOutput.writeFloat(floatConstant.f4value);
        }


        public void visitDoubleConstant(Clazz clazz, DoubleConstant doubleConstant)
        {
            dataOutput.writeDouble(doubleConstant.f8value);
        }


        public void visitStringConstant(Clazz clazz, StringConstant stringConstant)
        {
            dataOutput.writeShort(stringConstant.u2stringIndex);
        }


        public void visitUtf8Constant(Clazz clazz, Utf8Constant utf8Constant)
        {
            byte[] bytes = utf8Constant.getBytes();

            dataOutput.writeShort(bytes.length);
            dataOutput.write(bytes);
        }


        public void visitAnyRefConstant(Clazz clazz, RefConstant refConstant)
        {
            dataOutput.writeShort(refConstant.u2classIndex);
            dataOutput.writeShort(refConstant.u2nameAndTypeIndex);
        }


        public void visitClassConstant(Clazz clazz, ClassConstant classConstant)
        {
            dataOutput.writeShort(classConstant.u2nameIndex);
        }


        public void visitNameAndTypeConstant(Clazz clazz, NameAndTypeConstant nameAndTypeConstant)
        {
            dataOutput.writeShort(nameAndTypeConstant.u2nameIndex);
            dataOutput.writeShort(nameAndTypeConstant.u2descriptorIndex);
        }
    }


    // Implementations for AttributeVisitor.

    public void visitAnyAttribute(Clazz clazz, Attribute attribute)
    {
        // Write the attribute name index.
        dataOutput.writeShort(attribute.u2attributeNameIndex);

        // We'll write the attribute body into an array first, so we can
        // automatically figure out its length.
        ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();

        // Temporarily replace the current data output.
        RuntimeDataOutput oldDataOutput = dataOutput;
        dataOutput = new RuntimeDataOutput(new DataOutputStream(byteArrayOutputStream));

        // Write the attribute body into the array. Note that the
        // accept method with two dummy null arguments never throws
        // an UnsupportedOperationException.
        attribute.accept(clazz, null, null, attributeBodyWriter);

        // Restore the original data output.
        dataOutput = oldDataOutput;

        // Write the attribute length and body.
        byte[] info = byteArrayOutputStream.toByteArray();

        dataOutput.writeInt(info.length);
        dataOutput.write(info);
    }


    private class AttributeBodyWriter
    extends       SimplifiedVisitor
    implements    AttributeVisitor,
                  InnerClassesInfoVisitor,
                  ExceptionInfoVisitor,
                  StackMapFrameVisitor,
                  VerificationTypeVisitor,
                  LineNumberInfoVisitor,
                  LocalVariableInfoVisitor,
                  LocalVariableTypeInfoVisitor,
                  AnnotationVisitor,
                  ElementValueVisitor
    {
        // Implementations for AttributeVisitor.

        public void visitUnknownAttribute(Clazz clazz, UnknownAttribute unknownAttribute)
        {
            // Write the unknown information.
            byte[] info = new byte[unknownAttribute.u4attributeLength];
            dataOutput.write(info);
            unknownAttribute.info = info;
        }


        public void visitSourceFileAttribute(Clazz clazz, SourceFileAttribute sourceFileAttribute)
        {
            dataOutput.writeShort(sourceFileAttribute.u2sourceFileIndex);
        }


        public void visitSourceDirAttribute(Clazz clazz, SourceDirAttribute sourceDirAttribute)
        {
            dataOutput.writeShort(sourceDirAttribute.u2sourceDirIndex);
        }


        public void visitInnerClassesAttribute(Clazz clazz, InnerClassesAttribute innerClassesAttribute)
        {
            // Write the inner classes.
            dataOutput.writeShort(innerClassesAttribute.u2classesCount);

            innerClassesAttribute.innerClassEntriesAccept(clazz, this);
        }


        public void visitEnclosingMethodAttribute(Clazz clazz, EnclosingMethodAttribute enclosingMethodAttribute)
        {
            dataOutput.writeShort(enclosingMethodAttribute.u2classIndex);
            dataOutput.writeShort(enclosingMethodAttribute.u2nameAndTypeIndex);
        }


        public void visitDeprecatedAttribute(Clazz clazz, DeprecatedAttribute deprecatedAttribute)
        {
            // This attribute does not contain any additional information.
        }


        public void visitSyntheticAttribute(Clazz clazz, SyntheticAttribute syntheticAttribute)
        {
            // This attribute does not contain any additional information.
        }


        public void visitSignatureAttribute(Clazz clazz, SignatureAttribute signatureAttribute)
        {
            dataOutput.writeShort(signatureAttribute.u2signatureIndex);
        }


        public void visitConstantValueAttribute(Clazz clazz, Field field, ConstantValueAttribute constantValueAttribute)
        {
            dataOutput.writeShort(constantValueAttribute.u2constantValueIndex);
        }


        public void visitExceptionsAttribute(Clazz clazz, Method method, ExceptionsAttribute exceptionsAttribute)
        {
            // Write the exceptions.
            dataOutput.writeShort(exceptionsAttribute.u2exceptionIndexTableLength);

            for (int index = 0; index < exceptionsAttribute.u2exceptionIndexTableLength; index++)
            {
                dataOutput.writeShort(exceptionsAttribute.u2exceptionIndexTable[index]);
            }