jaroslav@1170: /**
jaroslav@1170:  * Back 2 Browser Bytecode Translator
jaroslav@1170:  * Copyright (C) 2012 Jaroslav Tulach <jaroslav.tulach@apidesign.org>
jaroslav@1170:  *
jaroslav@1170:  * This program is free software: you can redistribute it and/or modify
jaroslav@1170:  * it under the terms of the GNU General Public License as published by
jaroslav@1170:  * the Free Software Foundation, version 2 of the License.
jaroslav@1170:  *
jaroslav@1170:  * This program is distributed in the hope that it will be useful,
jaroslav@1170:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
jaroslav@1170:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
jaroslav@1170:  * GNU General Public License for more details.
jaroslav@1170:  *
jaroslav@1170:  * You should have received a copy of the GNU General Public License
jaroslav@1170:  * along with this program. Look for COPYING file in the top folder.
jaroslav@1170:  * If not, see http://opensource.org/licenses/GPL-2.0.
jaroslav@1170:  */
jaroslav@1170: package org.apidesign.bck2brwsr.launcher.fximpl;
jaroslav@1170: 
jaroslav@1170: import java.io.IOException;
jaroslav@1170: import java.io.InputStream;
jaroslav@1170: import java.net.URL;
jaroslav@1170: import java.net.URLClassLoader;
jaroslav@1170: import java.util.ArrayList;
jaroslav@1170: import java.util.Arrays;
jaroslav@1170: import java.util.List;
jaroslav@1170: import org.objectweb.asm.AnnotationVisitor;
jaroslav@1170: import org.objectweb.asm.ClassReader;
jaroslav@1170: import org.objectweb.asm.ClassVisitor;
jaroslav@1170: import org.objectweb.asm.ClassWriter;
jaroslav@1170: import org.objectweb.asm.Label;
jaroslav@1170: import org.objectweb.asm.MethodVisitor;
jaroslav@1170: import org.objectweb.asm.Opcodes;
jaroslav@1170: import org.objectweb.asm.Type;
jaroslav@1170: 
jaroslav@1170: /** 
jaroslav@1170:  *
jaroslav@1170:  * @author Jaroslav Tulach <jaroslav.tulach@apidesign.org>
jaroslav@1170:  */
jaroslav@1170: public abstract class JsClassLoader extends URLClassLoader {
jaroslav@1170:     JsClassLoader(URL[] urls, ClassLoader parent) {
jaroslav@1170:         super(urls, parent);
jaroslav@1170:     }
jaroslav@1170: 
jaroslav@1170:     @Override
jaroslav@1170:     protected Class<?> findClass(String name) throws ClassNotFoundException {
jaroslav@1170:         URL u = findResource(name.replace('.', '/') + ".class");
jaroslav@1170:         if (u != null) {
jaroslav@1170:             InputStream is = null;
jaroslav@1170:             try {
jaroslav@1170:                 is = u.openStream();
jaroslav@1170:                 ClassReader cr = new ClassReader(is);
jaroslav@1170:                 ClassWriter w = new ClassWriter(cr, ClassWriter.COMPUTE_MAXS | ClassWriter.COMPUTE_FRAMES);
jaroslav@1170:                 FindInClass fic = new FindInClass(w);
jaroslav@1170:                 cr.accept(fic, 0);
jaroslav@1170:                 byte[] arr = w.toByteArray();
jaroslav@1170:                 return defineClass(name, arr, 0, arr.length);
jaroslav@1170:             } catch (IOException ex) {
jaroslav@1170:                 throw new ClassNotFoundException("Can't load " + name, ex);
jaroslav@1170:             } finally {
jaroslav@1170:                 try {
jaroslav@1170:                     if (is != null) is.close();
jaroslav@1170:                 } catch (IOException ex) {
jaroslav@1170:                     throw new ClassNotFoundException(null, ex);
jaroslav@1170:                 }
jaroslav@1170:             }
jaroslav@1170:         }
jaroslav@1170:         if (name.startsWith("org.apidesign.bck2brwsr.launcher.fximpl.JsClassLoader")) {
jaroslav@1170:             return Class.forName(name);
jaroslav@1170:         }
jaroslav@1170:         
jaroslav@1170:         return super.findClass(name);
jaroslav@1170:     }
jaroslav@1170:     
jaroslav@1170:     public final Fn define(String code, String... names) {
jaroslav@1170:         return defineFn(code, names);
jaroslav@1170:     }
jaroslav@1170:     
jaroslav@1170: 
jaroslav@1170:     protected abstract Fn defineFn(String code, String... names);
jaroslav@1170:     
jaroslav@1170:     public static abstract class Fn {
jaroslav@1170:         public abstract Object invoke(Object... args) throws Exception;
jaroslav@1170:     }
jaroslav@1170:     
jaroslav@1170:     
jaroslav@1170:     private static final class FindInClass extends ClassVisitor {
jaroslav@1170:         private String name;
jaroslav@1170:         
jaroslav@1170:         public FindInClass(ClassVisitor cv) {
jaroslav@1170:             super(Opcodes.ASM4, cv);
jaroslav@1170:         }
jaroslav@1170: 
jaroslav@1170:         @Override
jaroslav@1170:         public void visit(int version, int access, String name, String signature, String superName, String[] interfaces) {
jaroslav@1170:             this.name = name;
jaroslav@1170:             super.visit(version, access, name, signature, superName, interfaces);
jaroslav@1170:         }
jaroslav@1170:         
jaroslav@1170:         
jaroslav@1170: 
jaroslav@1170:         @Override
jaroslav@1170:         public MethodVisitor visitMethod(int access, String name, String desc, String signature, String[] exceptions) {
jaroslav@1170:             return new FindInMethod(name,
jaroslav@1170:                 super.visitMethod(access, name, desc, signature, exceptions)
jaroslav@1170:             );
jaroslav@1170:         }
jaroslav@1170:         
jaroslav@1170:         private final class FindInMethod extends MethodVisitor {
jaroslav@1170:             private final String name;
jaroslav@1170:             private List<String> args;
jaroslav@1170:             private String body;
jaroslav@1170:             
jaroslav@1170:             public FindInMethod(String name, MethodVisitor mv) {
jaroslav@1170:                 super(Opcodes.ASM4, mv);
jaroslav@1170:                 this.name = name;
jaroslav@1170:             }
jaroslav@1170: 
jaroslav@1170:             @Override
jaroslav@1170:             public AnnotationVisitor visitAnnotation(String desc, boolean visible) {
jaroslav@1170:                 if ("Lorg/apidesign/bck2brwsr/core/JavaScriptBody;".equals(desc)) { // NOI18N
jaroslav@1170:                     return new FindInAnno();
jaroslav@1170:                 }
jaroslav@1170:                 return super.visitAnnotation(desc, visible);
jaroslav@1170:             }
jaroslav@1170: 
jaroslav@1170:             private void generateJSBody(List<String> args, String body) {
jaroslav@1170:                 this.args = args;
jaroslav@1170:                 this.body = body;
jaroslav@1170:             }
jaroslav@1170:             
jaroslav@1170:             @Override
jaroslav@1170:             public void visitCode() {
jaroslav@1170:                 if (body == null) {
jaroslav@1170:                     return;
jaroslav@1170:                 } 
jaroslav@1170:                 
jaroslav@1170:                 super.visitFieldInsn(
jaroslav@1170:                     Opcodes.GETSTATIC, FindInClass.this.name, 
jaroslav@1170:                     "$$bck2brwsr$$" + name, 
jaroslav@1170:                     "Lorg/apidesign/bck2brwsr/launcher/fximpl/JsClassLoader$Fn;"
jaroslav@1170:                 );
jaroslav@1170:                 super.visitInsn(Opcodes.DUP);
jaroslav@1170:                 Label ifNotNull = new Label();
jaroslav@1170:                 super.visitJumpInsn(Opcodes.IFNONNULL, ifNotNull);
jaroslav@1170:                 
jaroslav@1170:                 // init Fn
jaroslav@1170:                 super.visitInsn(Opcodes.POP);
jaroslav@1170:                 super.visitLdcInsn(Type.getObjectType(FindInClass.this.name));
jaroslav@1170:                 super.visitMethodInsn(Opcodes.INVOKEVIRTUAL, 
jaroslav@1170:                     "java/lang/Class", "getClassLoader", "()Ljava/lang/ClassLoader;"
jaroslav@1170:                 );
jaroslav@1170:                 super.visitTypeInsn(Opcodes.CHECKCAST, "org/apidesign/bck2brwsr/launcher/fximpl/JsClassLoader");
jaroslav@1170:                 super.visitLdcInsn(body);
jaroslav@1170:                 super.visitIntInsn(Opcodes.SIPUSH, args.size());
jaroslav@1170:                 super.visitTypeInsn(Opcodes.ANEWARRAY, "java/lang/String");
jaroslav@1170:                 for (int i = 0; i < args.size(); i++) {
jaroslav@1170:                     String name = args.get(i);
jaroslav@1170:                     super.visitInsn(Opcodes.DUP);
jaroslav@1170:                     super.visitIntInsn(Opcodes.BIPUSH, i);
jaroslav@1170:                     super.visitLdcInsn(name);
jaroslav@1170:                     super.visitInsn(Opcodes.AASTORE);
jaroslav@1170:                 }
jaroslav@1170:                 super.visitMethodInsn(Opcodes.INVOKEVIRTUAL, 
jaroslav@1170:                     "org/apidesign/bck2brwsr/launcher/fximpl/JsClassLoader",
jaroslav@1170:                     "define", "(Ljava/lang/String;[Ljava/lang/String;)Lorg/apidesign/bck2brwsr/launcher/fximpl/JsClassLoader$Fn;"
jaroslav@1170:                 );
jaroslav@1170:                 // end of Fn init
jaroslav@1170:                 
jaroslav@1170:                 super.visitLabel(ifNotNull);
jaroslav@1170:                 super.visitIntInsn(Opcodes.SIPUSH, args.size());
jaroslav@1170:                 super.visitTypeInsn(Opcodes.ANEWARRAY, "java/lang/Object");
jaroslav@1170:                 super.visitMethodInsn(Opcodes.INVOKEVIRTUAL, 
jaroslav@1170:                     "org/apidesign/bck2brwsr/launcher/fximpl/JsClassLoader$Fn", "invoke", "([Ljava/lang/Object;)Ljava/lang/Object;"
jaroslav@1170:                 );
jaroslav@1170:                 super.visitInsn(Opcodes.ARETURN);
jaroslav@1170:             }
jaroslav@1170: 
jaroslav@1170:             @Override
jaroslav@1170:             public void visitEnd() {
jaroslav@1170:                 super.visitEnd();
jaroslav@1170:                 if (body != null) {
jaroslav@1170:                     FindInClass.this.visitField(
jaroslav@1170:                         Opcodes.ACC_PRIVATE | Opcodes.ACC_STATIC, 
jaroslav@1170:                         "$$bck2brwsr$$" + name, 
jaroslav@1170:                         "Lorg/apidesign/bck2brwsr/launcher/fximpl/JsClassLoader$Fn;", 
jaroslav@1170:                         null, null
jaroslav@1170:                     );
jaroslav@1170:                 }
jaroslav@1170:             }
jaroslav@1170:             
jaroslav@1170:             
jaroslav@1170:             
jaroslav@1170:             
jaroslav@1170:         
jaroslav@1170:             private final class FindInAnno extends AnnotationVisitor {
jaroslav@1170:                 private List<String> args = new ArrayList<String>();
jaroslav@1170:                 private String body;
jaroslav@1170: 
jaroslav@1170:                 public FindInAnno() {
jaroslav@1170:                     super(Opcodes.ASM4);
jaroslav@1170:                 }
jaroslav@1170: 
jaroslav@1170:                 @Override
jaroslav@1170:                 public void visit(String name, Object value) {
jaroslav@1170:                     if (name == null) {
jaroslav@1170:                         args.add((String) value);
jaroslav@1170:                         return;
jaroslav@1170:                     }
jaroslav@1170:                     assert name.equals("body");
jaroslav@1170:                     body = (String) value;
jaroslav@1170:                 }
jaroslav@1170: 
jaroslav@1170:                 @Override
jaroslav@1170:                 public AnnotationVisitor visitArray(String name) {
jaroslav@1170:                     return this;
jaroslav@1170:                 }
jaroslav@1170: 
jaroslav@1170:                 @Override
jaroslav@1170:                 public void visitEnd() {
jaroslav@1170:                     if (body != null) {
jaroslav@1170:                         generateJSBody(args, body);
jaroslav@1170:                     }
jaroslav@1170:                 }
jaroslav@1170:             }
jaroslav@1170:         }
jaroslav@1170:     }
jaroslav@1170: }