001    /*
002     * To change this template, choose Tools | Templates
003     * and open the template in the editor.
004     */
005    package org.bridj.util;
006    import java.io.IOException;
007    import java.lang.reflect.Modifier;
008    import java.lang.reflect.ParameterizedType;
009    import org.bridj.Pointer;
010    import org.objectweb.asm.*;
011    import static org.objectweb.asm.Opcodes.*;
012    
013    /**
014     * Utilities for <a href="http://asm.ow2.org/">ASM</a>.
015     * @author ochafik
016     */
017    public class ASMUtils {
018        
019        public static String typeDesc(java.lang.reflect.Type t) {
020            if (t instanceof Class) {
021                Class c = (Class)t;
022                if (c == Pointer.class)
023                    return "Pointer";
024                if (c.isPrimitive()) {
025                    String s = c.getSimpleName();
026                    return Character.toUpperCase(s.charAt(0)) + s.substring(1);
027                } else if (c.isArray()) {
028                    return typeDesc(c.getComponentType()) + "Array";
029                }
030                return c.getName().replace('.', '_');
031            } else {
032                ParameterizedType p = (ParameterizedType)t;
033                StringBuilder b = new StringBuilder(typeDesc(p.getRawType()));
034                for (java.lang.reflect.Type pp : p.getActualTypeArguments())
035                    b.append("_").append(typeDesc(pp));
036                return b.toString();
037            }
038        }
039        public static void addSuperCall(ClassVisitor cv, String superClassInternalName) {
040            MethodVisitor mv = cv.visitMethod(ACC_PUBLIC, "<init>", "()V", null, null);
041            mv.visitCode();
042            mv.visitVarInsn(ALOAD, 0);
043            mv.visitMethodInsn(INVOKESPECIAL, superClassInternalName, "<init>", "()V");
044            mv.visitInsn(RETURN);
045            mv.visitMaxs(1, 1);
046            mv.visitEnd();
047        }
048        public static <T> Class<? extends T> createSubclassWithSynchronizedNativeMethodsAndNoStaticFields(Class<T> original, ClassDefiner classDefiner) throws IOException {
049            String suffix = "$SynchronizedNative";
050            final String originalInternalName = JNIUtils.getNativeName(original);
051            final String synchronizedName = original.getName() + suffix;
052            final String synchronizedInternalName = originalInternalName + suffix;
053            
054            ClassWriter classWriter = new ClassWriter(0);
055            //TraceClassVisitor traceVisitor = new TraceClassVisitor(classWriter, new PrintWriter(System.out));
056            ClassVisitor cv = new ClassVisitor(ASM4, classWriter) {
057    
058                @Override
059                public void visit(int version, int access, String name, String signature, String superName, String[] interfaces) {
060                    super.visit(version, access, synchronizedInternalName, null, originalInternalName, new String[0]);
061                    addSuperCall(cv, originalInternalName);
062                }
063    
064                @Override
065                public void visitInnerClass(String name, String outerName, String innerName, int access) {
066                    // Do nothing.
067                }
068                
069                @Override
070                public FieldVisitor visitField(int access, String name, String desc, String signature, Object value) {
071                    return null;
072                }
073                
074                @Override
075                public MethodVisitor visitMethod(int access, String name, String desc, String signature, String[] exceptions) {
076                    if (!Modifier.isNative(access))
077                        return null;
078                    
079                    return super.visitMethod(access | Modifier.SYNCHRONIZED, name, desc, signature, exceptions);
080                }
081            };
082                    
083            ClassReader classReader = new ClassReader(original.getName());
084            classReader.accept(cv, 0);
085            return (Class<? extends T>) classDefiner.defineClass(synchronizedName, classWriter.toByteArray());
086        }
087    }