programclassreader.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.DataInput;

/**
 * This ClassVisitor fills out the ProgramClass objects that it visits with data
 * from the given DataInput object.
 *
 * @author Eric Lafortune
 */
public class ProgramClassReader
extends      SimplifiedVisitor
implements   ClassVisitor,
             MemberVisitor,
             ConstantVisitor,
             AttributeVisitor,
             InnerClassesInfoVisitor,
             ExceptionInfoVisitor,
             StackMapFrameVisitor,
             VerificationTypeVisitor,
             LineNumberInfoVisitor,
             LocalVariableInfoVisitor,
             LocalVariableTypeInfoVisitor,
             AnnotationVisitor,
             ElementValueVisitor
{
    private RuntimeDataInput dataInput;


    /**
     * Creates a new ProgramClassReader for reading from the given DataInput.
     */
    public ProgramClassReader(DataInput dataInput)
    {
        this.dataInput = new RuntimeDataInput(dataInput);
    }


    // Implementations for ClassVisitor.

    public void visitProgramClass(ProgramClass programClass)
    {
        // Read and check the magic number.
        programClass.u4magic = dataInput.readInt();

        ClassUtil.checkMagicNumber(programClass.u4magic);

        // Read and check the version numbers.
        int u2minorVersion = dataInput.readUnsignedShort();
        int u2majorVersion = dataInput.readUnsignedShort();

        programClass.u4version = ClassUtil.internalClassVersion(u2majorVersion,
                                                                u2minorVersion);

        ClassUtil.checkVersionNumbers(programClass.u4version);

        // Read the constant pool. Note that the first entry is not used.
        programClass.u2constantPoolCount = dataInput.readUnsignedShort();

        programClass.constantPool = new Constant[programClass.u2constantPoolCount];
        for (int index = 1; index < programClass.u2constantPoolCount; index++)
        {
            Constant constant = createConstant();
            constant.accept(programClass, this);
            programClass.constantPool[index] = constant;

            // Long constants and double constants take up two entries in the
            // constant pool.
            int tag = constant.getTag();
            if (tag == ClassConstants.CONSTANT_Long ||
                tag == ClassConstants.CONSTANT_Double)
            {
                programClass.constantPool[++index] = null;
            }
        }

        // Read the general class information.
        programClass.u2accessFlags = dataInput.readUnsignedShort();
        programClass.u2thisClass   = dataInput.readUnsignedShort();
        programClass.u2superClass  = dataInput.readUnsignedShort();

        // Read the interfaces.
        programClass.u2interfacesCount = dataInput.readUnsignedShort();

        programClass.u2interfaces = new int[programClass.u2interfacesCount];
        for (int index = 0; index < programClass.u2interfacesCount; index++)
        {
            programClass.u2interfaces[index] = dataInput.readUnsignedShort();
        }

        // Read the fields.
        programClass.u2fieldsCount = dataInput.readUnsignedShort();

        programClass.fields = new ProgramField[programClass.u2fieldsCount];
        for (int index = 0; index < programClass.u2fieldsCount; index++)
        {
            ProgramField programField = new ProgramField();
            this.visitProgramField(programClass, programField);
            programClass.fields[index] = programField;
        }

        // Read the methods.
        programClass.u2methodsCount = dataInput.readUnsignedShort();

        programClass.methods = new ProgramMethod[programClass.u2methodsCount];
        for (int index = 0; index < programClass.u2methodsCount; index++)
        {
            ProgramMethod programMethod = new ProgramMethod();
            this.visitProgramMethod(programClass, programMethod);
            programClass.methods[index] = programMethod;
        }

        // Read the class attributes.
        programClass.u2attributesCount = dataInput.readUnsignedShort();

        programClass.attributes = new Attribute[programClass.u2attributesCount];
        for (int index = 0; index < programClass.u2attributesCount; index++)
        {
            Attribute attribute = createAttribute(programClass);
            attribute.accept(programClass, this);
            programClass.attributes[index] = attribute;
        }
    }


    public void visitLibraryClass(LibraryClass libraryClass)
    {
    }


    // Implementations for MemberVisitor.

    public void visitProgramField(ProgramClass programClass, ProgramField programField)
    {
        // Read the general field information.
        programField.u2accessFlags     = dataInput.readUnsignedShort();
        programField.u2nameIndex       = dataInput.readUnsignedShort();
        programField.u2descriptorIndex = dataInput.readUnsignedShort();

        // Read the field attributes.
        programField.u2attributesCount = dataInput.readUnsignedShort();

        programField.attributes = new Attribute[programField.u2attributesCount];
        for (int index = 0; index < programField.u2attributesCount; index++)
        {
            Attribute attribute = createAttribute(programClass);
            attribute.accept(programClass, programField, this);
            programField.attributes[index] = attribute;
        }
    }


    public void visitProgramMethod(ProgramClass programClass, ProgramMethod programMethod)
    {
        // Read the general method information.
        programMethod.u2accessFlags     = dataInput.readUnsignedShort();
        programMethod.u2nameIndex       = dataInput.readUnsignedShort();
        programMethod.u2descriptorIndex = dataInput.readUnsignedShort();

        // Read the method attributes.
        programMethod.u2attributesCount = dataInput.readUnsignedShort();

        programMethod.attributes = new Attribute[programMethod.u2attributesCount];
        for (int index = 0; index < programMethod.u2attributesCount; index++)
        {
            Attribute attribute = createAttribute(programClass);
            attribute.accept(programClass, programMethod, this);
            programMethod.attributes[index] = attribute;
        }
    }


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


    // Implementations for ConstantVisitor.

    public void visitIntegerConstant(Clazz clazz, IntegerConstant integerConstant)
    {
        integerConstant.u4value = dataInput.readInt();
    }


    public void visitLongConstant(Clazz clazz, LongConstant longConstant)
    {
        longConstant.u8value = dataInput.readLong();
    }


    public void visitFloatConstant(Clazz clazz, FloatConstant floatConstant)
    {
        floatConstant.f4value = dataInput.readFloat();
    }


    public void visitDoubleConstant(Clazz clazz, DoubleConstant doubleConstant)
    {
        doubleConstant.f8value = dataInput.readDouble();
    }


    public void visitStringConstant(Clazz clazz, StringConstant stringConstant)
    {
        stringConstant.u2stringIndex = dataInput.readUnsignedShort();
    }


    public void visitUtf8Constant(Clazz clazz, Utf8Constant utf8Constant)
    {
        int u2length = dataInput.readUnsignedShort();

        // Read the UTF-8 bytes.
        byte[] bytes = new byte[u2length];
        dataInput.readFully(bytes);
        utf8Constant.setBytes(bytes);
    }


    public void visitAnyRefConstant(Clazz clazz, RefConstant refConstant)
    {
        refConstant.u2classIndex       = dataInput.readUnsignedShort();
        refConstant.u2nameAndTypeIndex = dataInput.readUnsignedShort();
    }


    public void visitClassConstant(Clazz clazz, ClassConstant classConstant)
    {
        classConstant.u2nameIndex = dataInput.readUnsignedShort();
    }


    public void visitNameAndTypeConstant(Clazz clazz, NameAndTypeConstant nameAndTypeConstant)
    {
        nameAndTypeConstant.u2nameIndex       = dataInput.readUnsignedShort();
        nameAndTypeConstant.u2descriptorIndex = dataInput.readUnsignedShort();
    }


    // Implementations for AttributeVisitor.

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