/*

 * reserved comment block

 * DO NOT REMOVE OR ALTER!

 */

package com.sun.org.apache.bcel.internal.util;

/* ====================================================================

 * The Apache Software License, Version 1.1

 *

 * Copyright (c) 2002 The Apache Software Foundation.  All rights

 * reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 *

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions and the following disclaimer.

 *

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in

 *    the documentation and/or other materials provided with the

 *    distribution.

 *

 * 3. The end-user documentation included with the redistribution,

 *    if any, must include the following acknowledgment:

 *       "This product includes software developed by the

 *        Apache Software Foundation (http://www.apache.org/)."

 *    Alternately, this acknowledgment may appear in the software itself,

 *    if and wherever such third-party acknowledgments normally appear.

 *

 * 4. The names "Apache" and "Apache Software Foundation" and

 *    "Apache BCEL" must not be used to endorse or promote products

 *    derived from this software without prior written permission. For

 *    written permission, please contact apache@apache.org.

 *

 * 5. Products derived from this software may not be called "Apache",

 *    "Apache BCEL", nor may "Apache" appear in their name, without

 *    prior written permission of the Apache Software Foundation.

 *

 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED

 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES

 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE

 * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR

 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,

 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT

 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF

 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND

 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,

 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT

 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF

 * SUCH DAMAGE.

 * ====================================================================

 *

 * This software consists of voluntary contributions made by many

 * individuals on behalf of the Apache Software Foundation.  For more

 * information on the Apache Software Foundation, please see

 * <http://www.apache.org/>.

 */

import com.sun.org.apache.bcel.internal.classfile.*;

import com.sun.org.apache.bcel.internal.generic.*;

import com.sun.org.apache.bcel.internal.Repository;

import com.sun.org.apache.bcel.internal.Constants;

import java.io.*;

/**

 * This class takes a given JavaClass object and converts it to a

 * Java program that creates that very class using BCEL. This

 * gives new users of BCEL a useful example showing how things

 * are done with BCEL. It does not cover all features of BCEL,

 * but tries to mimic hand-written code as close as possible.

 *

 * @author <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A>

 */

public class BCELifier extends com.sun.org.apache.bcel.internal.classfile.EmptyVisitor {

  private JavaClass         _clazz;

  private PrintWriter       _out;

  private ConstantPoolGen   _cp;

  /** @param clazz Java class to "decompile"

   * @param out where to output Java program

   */

  public BCELifier(JavaClass clazz, OutputStream out) {

    _clazz = clazz;

    _out = new PrintWriter(out);

    _cp = new ConstantPoolGen(_clazz.getConstantPool());

  }

  /** Start Java code generation

   */

  public void start() {

    visitJavaClass(_clazz);

    _out.flush();

  }

  public void visitJavaClass(JavaClass clazz) {

    String class_name   = clazz.getClassName();

    String super_name   = clazz.getSuperclassName();

    String package_name = clazz.getPackageName();

    String inter        = Utility.printArray(clazz.getInterfaceNames(),

                                             false, true);

    if(!"".equals(package_name)) {

      class_name = class_name.substring(package_name.length() + 1);

      _out.println("package " + package_name + ";\n");

     }

    _out.println("import com.sun.org.apache.bcel.internal.generic.*;");

    _out.println("import com.sun.org.apache.bcel.internal.classfile.*;");

    _out.println("import com.sun.org.apache.bcel.internal.*;");

    _out.println("import java.io.*;\n");

    _out.println("public class " + class_name + "Creator implements Constants {");

    _out.println("  private InstructionFactory _factory;");

    _out.println("  private ConstantPoolGen    _cp;");

    _out.println("  private ClassGen           _cg;\n");

    _out.println("  public " + class_name  + "Creator() {");

    _out.println("    _cg = new ClassGen(\"" +

                 (("".equals(package_name))? class_name :

                  package_name + "." + class_name) +

                 "\", \"" + super_name + "\", " +

                 "\"" + clazz.getSourceFileName() + "\", " +

                 printFlags(clazz.getAccessFlags(), true) + ", " +

                 "new String[] { " + inter + " });\n");

    _out.println("    _cp = _cg.getConstantPool();");

    _out.println("    _factory = new InstructionFactory(_cg, _cp);");

    _out.println("  }\n");

    printCreate();

    Field[] fields = clazz.getFields();

    if(fields.length > 0) {

      _out.println("  private void createFields() {");

      _out.println("    FieldGen field;");

      for(int i=0; i < fields.length; i++) {

        fields[i].accept(this);

      }

      _out.println("  }\n");

    }

    Method[] methods = clazz.getMethods();

    for(int i=0; i < methods.length; i++) {

      _out.println("  private void createMethod_" + i + "() {");

      methods[i].accept(this);

      _out.println("  }\n");

    }

    printMain();

    _out.println("}");

  }

  private void printCreate() {

    _out.println("  public void create(OutputStream out) throws IOException {");

    Field[] fields = _clazz.getFields();

    if(fields.length > 0) {

      _out.println("    createFields();");

    }

    Method[] methods = _clazz.getMethods();

    for(int i=0; i < methods.length; i++) {

      _out.println("    createMethod_" + i + "();");

    }

    _out.println("    _cg.getJavaClass().dump(out);");

    _out.println("  }\n");

  }

  private void printMain() {

    String   class_name   = _clazz.getClassName();

    _out.println("  public static void _main(String[] args) throws Exception {");

    _out.println("    " + class_name + "Creator creator = new " +

                 class_name + "Creator();");

    _out.println("    creator.create(new FileOutputStream(\"" + class_name +

                 ".class\"));");

    _out.println("  }");

  }

  public void visitField(Field field) {

    _out.println("\n    field = new FieldGen(" +

                 printFlags(field.getAccessFlags()) +

                 ", " + printType(field.getSignature()) + ", \"" +

                 field.getName() + "\", _cp);");

    ConstantValue cv = field.getConstantValue();

    if(cv != null) {

      String value = cv.toString();

      _out.println("    field.setInitValue(" + value + ")");

    }

    _out.println("    _cg.addField(field.getField());");

  }

  public void visitMethod(Method method) {

    MethodGen mg = new MethodGen(method, _clazz.getClassName(), _cp);

    Type   result_type = mg.getReturnType();

    Type[] arg_types   = mg.getArgumentTypes();

    _out.println("    InstructionList il = new InstructionList();");

    _out.println("    MethodGen method = new MethodGen(" +

                 printFlags(method.getAccessFlags()) +

                 ", " + printType(result_type) +

                 ", " + printArgumentTypes(arg_types) + ", " +

                 "new String[] { " +

                 Utility.printArray(mg.getArgumentNames(), false, true) +

                 " }, \"" + method.getName() + "\", \"" +

                 _clazz.getClassName() + "\", il, _cp);\n");

    BCELFactory factory = new BCELFactory(mg, _out);

    factory.start();

    _out.println("    method.setMaxStack();");

    _out.println("    method.setMaxLocals();");

    _out.println("    _cg.addMethod(method.getMethod());");

    _out.println("    il.dispose();");

  }

  static String printFlags(int flags) {

    return printFlags(flags, false);

  }

  static String printFlags(int flags, boolean for_class) {

    if(flags == 0)

      return "0";

    StringBuffer buf = new StringBuffer();

    for(int i=0, pow=1; i <= Constants.MAX_ACC_FLAG; i++) {

      if((flags & pow) != 0) {

        if((pow == Constants.ACC_SYNCHRONIZED) && for_class)

          buf.append("ACC_SUPER | ");

        else

          buf.append("ACC_" + Constants.ACCESS_NAMES[i].toUpperCase() + " | ");

      }

      pow <<= 1;

    }

    String str = buf.toString();

    return str.substring(0, str.length() - 3);

  }

  static String printArgumentTypes(Type[] arg_types) {

    if(arg_types.length == 0)

      return "Type.NO_ARGS";

    StringBuffer args = new StringBuffer();

    for(int i=0; i < arg_types.length; i++) {

      args.append(printType(arg_types[i]));

      if(i < arg_types.length - 1)

        args.append(", ");

    }

    return "new Type[] { " + args.toString() + " }";

  }

  static String printType(Type type) {

    return printType(type.getSignature());

  }

  static String printType(String signature) {

    Type type = Type.getType(signature);

    byte t    = type.getType();

    if(t <= Constants.T_VOID) {

      return "Type." + Constants.TYPE_NAMES[t].toUpperCase();

    } else if(type.toString().equals("java.lang.String")) {

      return "Type.STRING";

    } else if(type.toString().equals("java.lang.Object")) {

      return "Type.OBJECT";

    } else if(type.toString().equals("java.lang.StringBuffer")) {

      return "Type.STRINGBUFFER";

    } else if(type instanceof ArrayType) {

      ArrayType at = (ArrayType)type;

      return "new ArrayType(" + printType(at.getBasicType()) +

        ", " + at.getDimensions() + ")";

    } else {

      return "new ObjectType(\"" + Utility.signatureToString(signature, false) +

        "\")";

    }

  }

  /** Default _main method

   */

  public static void _main(String[] argv) throws Exception {

    JavaClass java_class;

    String    name = argv[0];

    if((java_class = Repository.lookupClass(name)) == null)

      java_class = new ClassParser(name).parse(); // May throw IOException

    BCELifier bcelifier = new BCELifier(java_class, System.out);

    bcelifier.start();

  }

}