/**

  * Back 2 Browser Bytecode Translator

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

  *

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

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

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

  *

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

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

  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

  * GNU General Public License for more details.

  *

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

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

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

  */

 package org.apidesign.vm4brwsr;

 import java.io.InputStream;

 import java.lang.invoke.CallSite;

 import java.lang.invoke.MethodHandles;

 import java.lang.invoke.MethodType;

 import java.lang.reflect.Method;

 import org.objectweb.asm.ClassReader;

 import org.objectweb.asm.ClassVisitor;

 import org.objectweb.asm.ClassWriter;

 import org.objectweb.asm.Handle;

 import org.objectweb.asm.MethodVisitor;

 import org.objectweb.asm.Opcodes;

 import static org.objectweb.asm.Opcodes.ASM4;

 import static org.objectweb.asm.Opcodes.INVOKESTATIC;

 import static org.testng.Assert.*;

 import org.testng.annotations.BeforeClass;

 import org.testng.annotations.Test;

 /**

  *

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

  */

 public class InvokeDynamicTest {

     private static Class<?> invokeDynamicClass;

     @Test public void simpleDynamicInJava() throws Exception {

         Method m = invokeDynamicClass.getMethod("dynamicSay");

         Object ret = m.invoke(m);

         assertEquals(ret, "Hello from Dynamic!");

     }

 /*    

     private static TestVM code;

     @BeforeClass

     public void compileTheCode() throws Exception {

         code = TestVM.compileClass(InvokeDynamic.class.getName());

     }

     @AfterClass

     public static void releaseTheCode() {

         code = null;

     }

     private void assertExec(

             String msg, Class clazz, String method, Object expRes, Object... args

     ) throws Exception {

         code.assertExec(msg, clazz, method, expRes, args);

     }

  */

     //

     // the following code is inspired by 

     // https://code.google.com/p/indy-maven-plugin/

     // which I don't want to use, as it is not in a public repository

     //

     @BeforeClass 

     public static void prepareClass() throws Exception {

         InputStream input = InvokeDynamic.class.getResourceAsStream("InvokeDynamic.class");

         assertNotNull(input, "Class found");

         ClassReader reader = new ClassReader(input);

         ClassWriter writer = new ClassWriter(reader, 0);

         reader.accept(

                 new ClassVisitor(ASM4, writer) {

                     @Override

                     public MethodVisitor visitMethod(int access, String name, String desc, String signature, String[] exceptions

                     ) {

                         MethodVisitor mv = super.visitMethod(access, name, desc, signature, exceptions);

                         return new InvokeDynamicProcessor(mv);

                     }

                 },

                 0);

         input.close();

         final byte[] invokeDynamicBytes = writer.toByteArray();

         ClassLoader l = new ClassLoader() {

             @Override

             public Class<?> loadClass(String name) throws ClassNotFoundException {

                 if (name.equals(InvokeDynamic.class.getName())) {

                     return defineClass(name, invokeDynamicBytes, 0, invokeDynamicBytes.length);

                 }

                 return super.loadClass(name);

             }

         };

         invokeDynamicClass = l.loadClass(InvokeDynamic.class.getName());

     }

     private static class InvokeDynamicProcessor extends MethodVisitor {

         InvokeDynamicProcessor(MethodVisitor mv) {

             super(ASM4, mv);

         }

         @Override

         public void visitMethodInsn(int opcode, String owner, String name, String desc) {

             if (opcode == INVOKESTATIC) {

                 if (name.startsWith("TEST_dynamic_")) {

                     final String shortName = name.substring(13);

                     Handle mh = new Handle(

                         Opcodes.H_INVOKESTATIC, owner, shortName,

                         MethodType.methodType(

                             CallSite.class,

                             MethodHandles.Lookup.class,

                             String.class, 

                             MethodType.class

                         ).toMethodDescriptorString()

                     );

                     super.visitInvokeDynamicInsn(shortName, desc, mh);

                     return;

                 }

             }

             super.visitMethodInsn(opcode, owner, name, desc);

         }

     }

 }