hg/bck2brwsr: src/main/java/org/apidesign/java4browser/ByteCodeToJavaScript.java@4679bf342a1f

     1 /*

     2 Java 4 Browser Bytecode Translator

     3 Copyright (C) 2012-2012 Jaroslav Tulach <jaroslav.tulach@apidesign.org>

     5 This program is free software: you can redistribute it and/or modify

     6 it under the terms of the GNU General Public License as published by

     7 the Free Software Foundation, version 2 of the License.

     9 This program is distributed in the hope that it will be useful,

    10 but WITHOUT ANY WARRANTY; without even the implied warranty of

    11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

    12 GNU General Public License for more details.

    14 You should have received a copy of the GNU General Public License

    15 along with this program. Look for COPYING file in the top folder.

    16 If not, see http://opensource.org/licenses/GPL-2.0.

    17 */

    18 package org.apidesign.java4browser;

    20 import java.io.IOException;

    21 import java.io.InputStream;

    22 import java.util.List;

    23 import static org.netbeans.modules.classfile.ByteCodes.*;

    24 import org.netbeans.modules.classfile.ClassFile;

    25 import org.netbeans.modules.classfile.Code;

    26 import org.netbeans.modules.classfile.Method;

    27 import org.netbeans.modules.classfile.Parameter;

    29 /** Translator of the code inside class files to JavaScript.

    30  *

    31  * @author Jaroslav Tulach <jtulach@netbeans.org>

    32  */

    33 public final class ByteCodeToJavaScript {

    34     private final ClassFile jc;

    35     private final Appendable out;

    37     private ByteCodeToJavaScript(ClassFile jc, Appendable out) {

    38         this.jc = jc;

    39         this.out = out;

    40     }

    42     /** Converts a given class file to a JavaScript version.

    43      * @param fileName the name of the file we are reading

    44      * @param classFile input stream with code of the .class file

    45      * @param out a {@link StringBuilder} or similar to generate the output to

    46      * @throws IOException if something goes wrong during read or write or translating

    47      */

    48     public static void compile(String fileName, InputStream classFile, Appendable out) throws IOException {

    49         ClassFile jc = new ClassFile(classFile, true);

    50         ByteCodeToJavaScript compiler = new ByteCodeToJavaScript(jc, out);

    51         for (Method m : jc.getMethods()) {

    52             if (m.isStatic()) {

    53                 compiler.generateStaticMethod(m);

    54             }

    55         }

    56     }

    57     private void generateStaticMethod(Method m) throws IOException {

    58         out.append("\nfunction ").append(

    59             jc.getName().getExternalName().replace('.', '_')

    60         ).append('_').append(

    61             m.getName()

    62         );

    63         out.append(m.getReturnType());

    64         List<Parameter> args = m.getParameters();

    65         for (Parameter t : args) {

    66             out.append(t.getDescriptor());

    67         }

    68         out.append('(');

    69         String space = "";

    70         for (int index = 0, i = 0; i < args.size(); i++) {

    71             out.append(space);

    72             out.append("arg").append(String.valueOf(index));

    73             space = ",";

    74             final String desc = args.get(i).getDescriptor();

    75             if ("D".equals(desc)) {

    76                 index += 2;

    77             } else {

    78                 index++;

    79             }

    80         }

    81         out.append(") {").append("\n  var ");

    82         final Code code = m.getCode();

    83         int len = code.getMaxLocals();

    84         space = "";

    85         for (int i = 0; i < len; i++) {

    86             out.append(space);

    87             out.append("var").append(String.valueOf(i));

    88             space = ",";

    89         }

    90         out.append(";\n  var stack = new Array(");

    91         out.append(Integer.toString(code.getMaxStack()));

    92         out.append(");\n");

    93         produceCode(code.getByteCodes());

    94         out.append("}");

    95     }

    97     private void produceCode(byte[] byteCodes) throws IOException {

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

    99             int prev = i;

   100             out.append("  ");

   101             final int c = (byteCodes[i] + 256) % 256;

   102             switch (c) {

   103                 case bc_aload_0:

   104                 case bc_iload_0:

   105                 case bc_lload_0:

   106                 case bc_fload_0:

   107                 case bc_dload_0:

   108                     out.append("stack.push(arg0);");

   109                     break;

   110                 case bc_aload_1:

   111                 case bc_iload_1:

   112                 case bc_lload_1:

   113                 case bc_fload_1:

   114                 case bc_dload_1:

   115                     out.append("stack.push(arg1);");

   116                     break;

   117                 case bc_aload_2:

   118                 case bc_iload_2:

   119                 case bc_lload_2:

   120                 case bc_fload_2:

   121                 case bc_dload_2:

   122                     out.append("stack.push(arg2);");

   123                     break;

   124                 case bc_iadd:

   125                 case bc_ladd:

   126                 case bc_fadd:

   127                 case bc_dadd:

   128                     out.append("stack.push(stack.pop() + stack.pop());");

   129                     break;

   130                 case bc_isub:

   131                 case bc_lsub:

   132                 case bc_fsub:

   133                 case bc_dsub:

   134                     out.append("stack.push(- stack.pop() + stack.pop());");

   135                     break;

   136                 case bc_imul:

   137                 case bc_lmul:

   138                 case bc_fmul:

   139                 case bc_dmul:

   140                     out.append("stack.push(stack.pop() * stack.pop());");

   141                     break;

   142                 case bc_ireturn:

   143                 case bc_lreturn:

   144                 case bc_freturn:

   145                 case bc_dreturn:

   146                     out.append("return stack.pop();");

   147                     break;

   148                 case bc_i2l:

   149                 case bc_i2f:

   150                 case bc_i2d:

   151                 case bc_l2i:

   152                 case bc_l2f:

   153                 case bc_l2d:

   154                 case bc_f2i:

   155                 case bc_f2l:

   156                 case bc_f2d:

   157                 case bc_d2i:

   158                 case bc_d2l:

   159                 case bc_d2f:

   160                 case bc_i2b:

   161                 case bc_i2c:

   162                 case bc_i2s:

   163                     out.append("/* number conversion */");

   164                     break;

   165             }

   166             out.append("/*");

   167             for (int j = prev; j <= i; j++) {

   168                 out.append(" ");

   169                 final int cc = (byteCodes[j] + 256) % 256;

   170                 out.append(Integer.toString(cc));

   171             }

   172             out.append("*/\n");

   173         }

   174     }

   175 }

author	Jaroslav Tulach <jaroslav.tulach@apidesign.org>
	Mon, 27 Aug 2012 05:47:44 +0200
changeset 2	4679bf342a1f
parent 1	48b1dce93691
child 3	e44f0155d946
permissions	-rw-r--r--