classfile.java

已经移植好的java虚拟机

/*
 *	ClassFile.java	1.9	99/04/06 SMI
 *
 * Copyright (c) 1997 Sun Microsystems, Inc. All Rights Reserved.
 *
 * This software is the confidential and proprietary information of Sun
 * Microsystems, Inc. ("Confidential Information").  You shall not
 * disclose such Confidential Information and shall use it only in
 * accordance with the terms of the license agreement you entered into
 * with Sun.
 *
 * SUN MAKES NO REPRESENTATIONS OR WARRANTIES ABOUT THE SUITABILITY OF THE
 * SOFTWARE, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
 * PURPOSE, OR NON-INFRINGEMENT. SUN SHALL NOT BE LIABLE FOR ANY DAMAGES
 * SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING OR DISTRIBUTING
 * THIS SOFTWARE OR ITS DERIVATIVES.
 * Use is subject to license terms.
 */

package util;

import components.*;
import vm.Const;

import java.io.DataInput;
import java.io.DataInputStream;
import java.io.DataOutput;
import java.io.IOException;
import java.io.PrintStream;
import java.io.InputStream;

import java.util.Enumeration;
import java.util.Hashtable;

/*
 * Reading of class files.
 * Which is different from reading a class from a multi-class file.
 * But not much.
 * Much of the real work is done in components.ClassInfo.
 *
 * There would be stuff for writing class files here, too, but we've
 * never been called upon to do that operation.
 *
 * Also includes a small test program for reading and dumping
 * a class file.
 */

public
class ClassFile
{
    // Input file name
    public String 	fileName;
    public boolean 	didRead = false;
    public Exception 	failureMode; // only for didRead == false.
    public boolean	verbose = false;
    public ClassInfo	clas;
    PrintStream   	log = System.out;
    InputStream		istream;

    // Identifies the classfile format
    int			minorID,
			majorID;

    public ClassFile(String name, boolean v ) {
	fileName = name;
	verbose	 = v;
	clas     = new ClassInfo( v );
	istream  = null;
    }

    public ClassFile(String name, InputStream i, boolean v ) {
	fileName = name;
	verbose	 = v;
	clas     = new ClassInfo( v );
	istream  = i;
    }

    // Read in the entire class file
    public boolean
    readClassFile( ConstantPool t ) {
	DataInputStream in = null;
	failureMode = null;
    done:
	try {
	    int magic;
	    if ( istream == null ){
		istream = new java.io.BufferedInputStream( new java.io.FileInputStream( fileName ) );
	    }
	    in = new DataInputStream( istream );
	    if ((magic = in.readInt()) != Const.JAVA_MAGIC) {
		failureMode = new IOException(Localizer.getString("classfile.bad_magic.ioexception"));
		break done; // bad magic -- bail immediately.
	    }

	    minorID = in.readShort();
	    majorID = in.readShort();

            /* Ignore major and minor versions for JDK 1.4 compatibility */
            
            /*
	    if (minorID != Const.JAVA_MINOR_VERSION) {
		failureMode = new IOException(Localizer.getString("classfile.bad_minor_version_number.ioexception"));
		break done; // bad magic -- bail immediately.
	    }

	    if (majorID != Const.JAVA_VERSION) {
		failureMode = new IOException(Localizer.getString("classfile.bad_major_version_number.ioexception"));
		break done; // bad magic -- bail immediately.
	    }
            */

	    if(verbose){
		log.println(Localizer.getString("classfile._file", fileName)+
			    Localizer.getString("classfile._magic/major/minor",
		                                Integer.toHexString( magic ),
		                                Integer.toHexString( majorID ),
		                                Integer.toHexString( minorID )));
	    }
	    clas.read( in, true, t );
	    didRead = true;
	} catch ( Exception e ){
	    failureMode = e;
	}
	if ( in != null ){
	    try{
		in.close();
	    } catch ( IOException e ){
		if (didRead==true){
		    didRead=false;
		    failureMode=e;
		}
	    }
	}
	return didRead;
    }

    public void
    dump( PrintStream o ){
	o.println(Localizer.getString("classfile.file", fileName));
	if ( ! didRead ){
	    o.println(Localizer.getString(
			  "classfile.could_not_be_read_because_of", 
			  failureMode));
	    if ( failureMode != null ) // stupid.
		failureMode.printStackTrace( o );
	    return;
	}
	clas.dump( o );
    }

    /*
     * Simple test program.
     * Parameters: list of class files to read and process.
     */
    public static void main( String clist[] ){
	for( int i = 0; i < clist.length; i++ ){
	    ClassFile f = new ClassFile( clist[i], true );
	    if (f.readClassFile( null ) != true ){
		System.out.println(Localizer.getString(
				        "classfile.read_of",
				        clist[i]));
		f.dump( System.out );
		continue;
	    }
	    f.clas.countReferences( true );
	    f.dump( System.out );
	}
    }

}