attrinfo.java

j2me 混淆包,用于混淆j2me的原代码用的

/* $Id: AttrInfo.java,v 1.3 2004/11/26 17:19:58 eric Exp $
 *
 * ProGuard -- shrinking, optimization, and obfuscation of Java class files.
 *
 * Copyright (c) 1999      Mark Welsh ([e-mail])
 * Copyright (c) 2002-2004 Eric Lafortune ([e-mail])
 *
 * This library is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser 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.classfile.attribute;


import proguard.classfile.*;
import proguard.classfile.attribute.annotation.*;

import java.io.*;

/**
 * Representation of an attribute. Specific attributes have their representations
 * sub-classed from this.
 *
 * @author Mark Welsh
 * @author Eric Lafortune
 */
public abstract class AttrInfo implements VisitorAccepter
{
    protected static final int CONSTANT_FIELD_SIZE = 6;


    public int u2attrNameIndex;
    //public int  u4attrLength;
    //public byte info[];

    /**
     * An extra field in which visitors can store information.
     */
    public Object visitorInfo;


    /**
     * Creates a new AttrInfo from the data passed.
     *
     * @throws java.io.IOException if class file is corrupt or incomplete
     */
    public static AttrInfo create(DataInput din, ClassFile classFile) throws IOException
    {
        // Instantiate based on attribute name
        int u2attrNameIndex = din.readUnsignedShort();
        int u4attrLength    = din.readInt();
        String attrName = classFile.getCpString(u2attrNameIndex);
        AttrInfo attrInfo =
            attrName.equals(ClassConstants.ATTR_InnerClasses)                         ? (AttrInfo)new InnerClassesAttrInfo():
            attrName.equals(ClassConstants.ATTR_EnclosingMethod)                      ? (AttrInfo)new EnclosingMethodAttrInfo():
            attrName.equals(ClassConstants.ATTR_ConstantValue)                        ? (AttrInfo)new ConstantValueAttrInfo():
            attrName.equals(ClassConstants.ATTR_Exceptions)                           ? (AttrInfo)new ExceptionsAttrInfo():
            attrName.equals(ClassConstants.ATTR_Code)                                 ? (AttrInfo)new CodeAttrInfo():
            attrName.equals(ClassConstants.ATTR_LineNumberTable)                      ? (AttrInfo)new LineNumberTableAttrInfo():
            attrName.equals(ClassConstants.ATTR_LocalVariableTable)                   ? (AttrInfo)new LocalVariableTableAttrInfo():
            attrName.equals(ClassConstants.ATTR_LocalVariableTypeTable)               ? (AttrInfo)new LocalVariableTypeTableAttrInfo():
            attrName.equals(ClassConstants.ATTR_SourceFile)                           ? (AttrInfo)new SourceFileAttrInfo():
            attrName.equals(ClassConstants.ATTR_SourceDir)                            ? (AttrInfo)new SourceDirAttrInfo():
            attrName.equals(ClassConstants.ATTR_Deprecated)                           ? (AttrInfo)new DeprecatedAttrInfo():
            attrName.equals(ClassConstants.ATTR_Synthetic)                            ? (AttrInfo)new SyntheticAttrInfo():
            attrName.equals(ClassConstants.ATTR_Signature)                            ? (AttrInfo)new SignatureAttrInfo():
            attrName.equals(ClassConstants.ATTR_RuntimeVisibleAnnotations)            ? (AttrInfo)new RuntimeVisibleAnnotationsAttrInfo():
            attrName.equals(ClassConstants.ATTR_RuntimeInvisibleAnnotations)          ? (AttrInfo)new RuntimeInvisibleAnnotationsAttrInfo():
            attrName.equals(ClassConstants.ATTR_RuntimeVisibleParameterAnnotations)   ? (AttrInfo)new RuntimeVisibleParameterAnnotationsAttrInfo():
            attrName.equals(ClassConstants.ATTR_RuntimeInvisibleParameterAnnotations) ? (AttrInfo)new RuntimeInvisibleParameterAnnotationsAttrInfo():
            attrName.equals(ClassConstants.ATTR_AnnotationDefault)                    ? (AttrInfo)new AnnotationDefaultAttrInfo():
                                                                                        (AttrInfo)new UnknownAttrInfo(u4attrLength);
        attrInfo.u2attrNameIndex = u2attrNameIndex;
        attrInfo.readInfo(din, classFile);

        return attrInfo;
    }


    protected AttrInfo()
    {
    }


    /**
     * Exports the representation to a DataOutput stream.
     */
    public final void write(DataOutput dout) throws IOException
    {
        dout.writeShort(u2attrNameIndex);
        dout.writeInt(getLength());
        writeInfo(dout);
    }


    /**
     * Returns the String name of the attribute; override this in subclasses.
     */
    public String getAttributeName(ClassFile classFile)
    {
        return classFile.getCpString(u2attrNameIndex);
    }


    // Abstract methods to be implemented by extensions.

    /**
     * Returns the length of the attribute, expressed in bytes.
     */
    protected abstract int getLength();


    /**
     * Reads the data following the header.
     */
    protected abstract void readInfo(DataInput din, ClassFile classFile) throws IOException;


    /**
     * Exports data following the header to a DataOutput stream.
     */
    protected abstract void writeInfo(DataOutput dout) throws IOException;


    /**
     * Accepts the given visitor.
     * This default implementation does nothing, which is useful for attributes
     * that require a context.
     */
    public void accept(ClassFile classFile, AttrInfoVisitor attrInfoVisitor)
    {
        // Do nothing.
    }

    /**
     * Accepts the given visitor in the context of a field.
     * This default implementation ignores the context.
     */
    public void accept(ClassFile classFile, FieldInfo fieldInfo, AttrInfoVisitor attrInfoVisitor)
    {
        accept(classFile, attrInfoVisitor);
    }

    /**
     * Accepts the given visitor in the context of a method.
     * This default implementation ignores the context.
     */
    public void accept(ClassFile classFile, MethodInfo methodInfo, AttrInfoVisitor attrInfoVisitor)
    {
        accept(classFile, attrInfoVisitor);
    }

    /**
     * Accepts the given visitor in the context of a method's code.
     * This default implementation ignores the code.
     */
    public void accept(ClassFile classFile, MethodInfo methodInfo, CodeAttrInfo codeAttrInfo, AttrInfoVisitor attrInfoVisitor)
    {
        accept(classFile, methodInfo, attrInfoVisitor);
    }


    // Implementations for VisitorAccepter.

    public Object getVisitorInfo()
    {
        return visitorInfo;
    }

    public void setVisitorInfo(Object visitorInfo)
    {
        this.visitorInfo = visitorInfo;
    }
}