1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/src/main/java/org/apidesign/java4browser/ByteCodeToJavaScript.java Mon Aug 27 05:08:30 2012 +0200
1.3 @@ -0,0 +1,121 @@
1.4 +/*
1.5 +Java 4 Browser Bytecode Translator
1.6 +Copyright (C) 2012-2012 Jaroslav Tulach <jaroslav.tulach@apidesign.org>
1.7 +
1.8 +This program is free software: you can redistribute it and/or modify
1.9 +it under the terms of the GNU General Public License as published by
1.10 +the Free Software Foundation, version 2 of the License.
1.11 +
1.12 +This program is distributed in the hope that it will be useful,
1.13 +but WITHOUT ANY WARRANTY; without even the implied warranty of
1.14 +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
1.15 +GNU General Public License for more details.
1.16 +
1.17 +You should have received a copy of the GNU General Public License
1.18 +along with this program. Look for COPYING file in the top folder.
1.19 +If not, see http://opensource.org/licenses/GPL-2.0.
1.20 +*/
1.21 +package org.apidesign.java4browser;
1.22 +
1.23 +import java.io.IOException;
1.24 +import java.io.InputStream;
1.25 +import java.util.List;
1.26 +import org.netbeans.modules.classfile.ByteCodes;
1.27 +import org.netbeans.modules.classfile.ClassFile;
1.28 +import org.netbeans.modules.classfile.Code;
1.29 +import org.netbeans.modules.classfile.Method;
1.30 +import org.netbeans.modules.classfile.Parameter;
1.31 +
1.32 +/** Translator of the code inside class files to JavaScript.
1.33 + *
1.34 + * @author Jaroslav Tulach <jtulach@netbeans.org>
1.35 + */
1.36 +public final class ByteCodeToJavaScript {
1.37 + private final ClassFile jc;
1.38 + private final Appendable out;
1.39 +
1.40 + private ByteCodeToJavaScript(ClassFile jc, Appendable out) {
1.41 + this.jc = jc;
1.42 + this.out = out;
1.43 + }
1.44 +
1.45 + /** Converts a given class file to a JavaScript version.
1.46 + * @param fileName the name of the file we are reading
1.47 + * @param classFile input stream with code of the .class file
1.48 + * @param out a {@link StringBuilder} or similar to generate the output to
1.49 + * @throws IOException if something goes wrong during read or write or translating
1.50 + */
1.51 + public static void compile(String fileName, InputStream classFile, Appendable out) throws IOException {
1.52 + ClassFile jc = new ClassFile(classFile, true);
1.53 + ByteCodeToJavaScript compiler = new ByteCodeToJavaScript(jc, out);
1.54 + for (Method m : jc.getMethods()) {
1.55 + if (m.isStatic()) {
1.56 + compiler.generateStaticMethod(m);
1.57 + }
1.58 + }
1.59 + }
1.60 + private void generateStaticMethod(Method m) throws IOException {
1.61 + out.append("function ").append(
1.62 + jc.getName().getExternalName().replace('.', '_')
1.63 + ).append('_').append(
1.64 + m.getName()
1.65 + );
1.66 + out.append(m.getReturnType());
1.67 + List<Parameter> args = m.getParameters();
1.68 + for (Parameter t : args) {
1.69 + out.append(t.getDescriptor());
1.70 + }
1.71 + out.append('(');
1.72 + String space = "";
1.73 + for (int i = 0; i < args.size(); i++) {
1.74 + out.append(space);
1.75 + out.append("arg").append(String.valueOf(i));
1.76 + space = ",";
1.77 + }
1.78 + out.append(") {").append("\n var ");
1.79 + final Code code = m.getCode();
1.80 + int len = code.getMaxLocals();
1.81 + space = "";
1.82 + for (int i = 0; i < len; i++) {
1.83 + out.append(space);
1.84 + out.append("var").append(String.valueOf(i));
1.85 + space = ",";
1.86 + }
1.87 + out.append(";\n var stack = new Array(");
1.88 + out.append(Integer.toString(code.getMaxStack()));
1.89 + out.append(");\n");
1.90 + produceCode(code.getByteCodes());
1.91 + out.append(";\nreturn 1;");
1.92 + out.append("}");
1.93 + }
1.94 +
1.95 + private void produceCode(byte[] byteCodes) throws IOException {
1.96 + for (int i = 0; i < byteCodes.length; i++) {
1.97 + int prev = i;
1.98 + out.append(" ");
1.99 + final int c = (byteCodes[i] + 256) % 256;
1.100 + switch (c) {
1.101 + case ByteCodes.bc_aload_0:
1.102 + case ByteCodes.bc_iload_0:
1.103 + out.append("stack.push(arg0);");
1.104 + break;
1.105 + case ByteCodes.bc_aload_1:
1.106 + case ByteCodes.bc_iload_1:
1.107 + out.append("stack.push(arg1);");
1.108 + break;
1.109 + case ByteCodes.bc_iadd:
1.110 + out.append("stack.push(stack.pop() + stack.pop());");
1.111 + break;
1.112 + case ByteCodes.bc_ireturn:
1.113 + out.append("return stack.pop();");
1.114 + }
1.115 + out.append("/*");
1.116 + for (int j = prev; j <= i; j++) {
1.117 + out.append(" ");
1.118 + final int cc = (byteCodes[j] + 256) % 256;
1.119 + out.append(Integer.toString(cc));
1.120 + }
1.121 + out.append("*/\n");
1.122 + }
1.123 + }
1.124 +}