Java Code Examples for org.objectweb.asm.ClassVisitor#visitEnd()

public Class<?> translate(Plugin plugin) throws IOException {
    // 防止出现 Class not found 的奇葩问题，使用缓存（目的是兼容热重载）
    InputStream inputStream = useCache ? new ByteArrayInputStream(cacheClasses.computeIfAbsent(target, n -> {
        try {
            return IO.readFully(Files.getResource(plugin, target.replace(".", "/") + ".class"));
        } catch (IOException e) {
            e.printStackTrace();
        }
        return new byte[0];
    })) : Files.getResource(plugin, target.replace(".", "/") + ".class");
    // 读取
    ClassReader classReader = new ClassReader(inputStream);
    ClassWriter classWriter = new ClassWriter(0);
    ClassVisitor classVisitor = new SimpleClassVisitor(this, classWriter);
    classReader.accept(classVisitor, ClassReader.EXPAND_FRAMES);
    classWriter.visitEnd();
    classVisitor.visitEnd();
    // 打印
    if (mapping || plugin instanceof InternalPlugin) {
        executorService.submit(this::printMapping);
    }
    // 因第三方插件调用该方法时会出现找不到类，所以第三方插件使用 BridgeLoader 加载类
    return plugin instanceof InternalPlugin ? AsmClassLoader.createNewClass(target, classWriter.toByteArray()) : BridgeLoader.createNewClass(target, classWriter.toByteArray());
}
 

public Class<?> translateBridge() throws IOException {
    Class<?> callerClass = Ref.getCallerClass(3).orElse(null);
    if (callerClass != null && !callerClass.getName().startsWith("io.izzel")) {
        throw new IllegalStateException();
    }
    ClassReader classReader = new ClassReader(Files.getTabooLibResource(target.replace(".", "/") + ".class"));
    ClassWriter classWriter = new ClassWriter(0);
    ClassVisitor classVisitor = new SimpleClassVisitor(this, classWriter);
    classReader.accept(classVisitor, ClassReader.EXPAND_FRAMES);
    classWriter.visitEnd();
    classVisitor.visitEnd();
    if (mapping || plugin instanceof InternalPlugin) {
        executorService.submit(this::printMapping);
    }
    return BridgeLoader.createNewClass(target, classWriter.toByteArray());
}
 

public static void inject(Plugin plugin, Class<?> clazz) {
    if (clazz.equals(TabooLib.class)) {
        for (Dependency dependency : TabooLib.class.getAnnotationsByType(Dependency.class)) {
            for (String url : dependency.url().split(";")) {
                try {
                    if (TDependency.requestLib(dependency.maven(), dependency.mavenRepo(), url)) {
                        break;
                    }
                } catch (Throwable ignored) {
                }
            }
        }
    } else {
        try {
            ClassReader classReader = new ClassReader(Files.getResource(plugin, clazz.getName().replace(".", "/") + ".class"));
            ClassWriter classWriter = new ClassWriter(0);
            ClassVisitor classVisitor = new DependencyClassVisitor(plugin, classWriter);
            classReader.accept(classVisitor, ClassReader.EXPAND_FRAMES);
            classWriter.visitEnd();
            classVisitor.visitEnd();
        } catch (Throwable t) {
            t.printStackTrace();
        }
    }
}
 

@Override
        public ClassVisitor wrap(TypeDescription typeDescription, ClassVisitor cv, Context context, TypePool typePool,
                                 FieldList<FieldDescription.InDefinedShape> fieldList, MethodList<?> methodList, int i, int i1)
        {
//            public void visit(int version, int modifiers, String name, String signature, String superName, String[] interfaces) {
            cv.visit(ClassFileVersion.JAVA_V9.getMinorMajorVersion(), typeDescription.getModifiers(), typeDescription.getInternalName(), null,
                     typeDescription.getSuperClass().asErasure().getInternalName(), typeDescription.getInterfaces().asErasures().toInternalNames());
            TypeDescription clazz = this.clazz;
            String internalName = clazz.getInternalName();
            String descriptor = clazz.getDescriptor();
            MethodList<InDefinedShape> declaredMethods = clazz.getDeclaredMethods();
            int methodsSize = declaredMethods.size();
            String implName = GENERATED_PREFIX + "." + clazz.getName();
            String internalImplName = GENERATED_PREFIX.replace('.', '/') + "/" + internalName;
            String descriptorImplName = "L" + GENERATED_PREFIX.replace('.', '/') + "/" + internalName + ";";

            FieldVisitor fv;
            MethodVisitor mv;
            AnnotationVisitor av0;

            cv.visitEnd();
            return cv;
        }
 

@Override
public Void visitPackage(PackageElement e, ClassVisitor classVisitor) {
  classVisitor.visit(
      SourceVersionUtils.sourceVersionToClassFileVersion(targetVersion),
      Opcodes.ACC_SYNTHETIC | Opcodes.ACC_ABSTRACT | Opcodes.ACC_INTERFACE,
      e.getQualifiedName().toString().replace('.', '/') + "/package-info",
      null,
      "java/lang/Object",
      new String[0]);

  visitAnnotations(e, classVisitor::visitAnnotation);

  new InnerClassesTable(descriptorFactory, accessFlagsUtils, e)
      .reportInnerClassReferences(classVisitor);

  classVisitor.visitEnd();

  return null;
}
 

public void accept(ClassVisitor visitor)
{
	String[] ints = interfaces.getInterfaces().stream().map(i -> i.getName()).toArray(String[]::new);

	visitor.visit(version, access, name.getName(), null, super_class.getName(), ints);
	visitor.visitSource(source, null);

	for (Annotation annotation : annotations.getAnnotations())
	{
		AnnotationVisitor av = visitor.visitAnnotation(annotation.getType().toString(), true);
		annotation.accept(av);
	}

	for (Field field : fields)
	{
		FieldVisitor fv = visitor.visitField(field.getAccessFlags(), field.getName(), field.getType().toString(), null, field.getValue());
		field.accept(fv);
	}

	for (Method method : methods)
	{
		String[] exceptions = method.getExceptions().getExceptions().stream().map(cl -> cl.getName()).toArray(String[]::new);
		if (exceptions.length == 0)
		{
			exceptions = null;
		}

		MethodVisitor mv = visitor.visitMethod(method.getAccessFlags(), method.getName(), method.getDescriptor().toString(), null, exceptions);
		method.accept(mv);
	}

	visitor.visitEnd();
}
 

public static void main(String[] args) throws Exception {
	ClassWriter cw = new ClassWriter(0);
	TraceClassVisitor tracer =
			new TraceClassVisitor(cw, new PrintWriter(System.out));
	ClassVisitor cv = tracer;
	String name = "Nerd";
	String generics = null;
	String superName = "java/lang/Object";
	String[] interfaces = null;
	int access = ACC_PUBLIC + ACC_INTERFACE;
	int version = V1_5;
	cv.visit(version, access, name, generics, superName, interfaces);

	int fieldAccess = ACC_PUBLIC + ACC_FINAL + ACC_STATIC;
	String shortDescriptor = Type.SHORT_TYPE.getDescriptor();
	FieldVisitor hair = cv.visitField(fieldAccess, "hair", shortDescriptor,
									  null, new Integer(0));
	hair.visitEnd();

	MethodVisitor playVideoGame =
		cv.visitMethod(ACC_PUBLIC + ACC_ABSTRACT, "playVideoGame",
					   "()V", null, null);
	// no code to define, just finish it up
	playVideoGame.visitEnd();
	cv.visitEnd(); // prints if using tracer
	byte[] b = cw.toByteArray();
	// can define or write to file:
	// defineClass(name, b, 0, b.length)
	// from findClass() in subclass of ClassLoader

	FileOutputStream fos = new FileOutputStream("Nerd.class");
	fos.write(b);
	fos.close();
}
 

public static void main(String[] args) throws Exception {
	ClassWriter cw = new ClassWriter(0);
	TraceClassVisitor tracer =
			new TraceClassVisitor(cw, new PrintWriter(System.out));
	ClassVisitor cv = tracer;
	String name = "Nerd";
	String generics = null;
	String superName = "java/lang/Object";
	String[] interfaces = null;
	int access = ACC_PUBLIC + ACC_INTERFACE;
	int version = V1_5;
	cv.visit(version, access, name, generics, superName, interfaces);

	int fieldAccess = ACC_PUBLIC + ACC_FINAL + ACC_STATIC;
	String shortDescriptor = Type.SHORT_TYPE.getDescriptor();
	FieldVisitor hair = cv.visitField(fieldAccess, "hair", shortDescriptor,
									  null, new Integer(0));
	hair.visitEnd();

	MethodVisitor playVideoGame =
		cv.visitMethod(ACC_PUBLIC + ACC_ABSTRACT, "playVideoGame",
					   "()V", null, null);
	// no code to define, just finish it up
	playVideoGame.visitEnd();
	cv.visitEnd(); // prints if using tracer
	byte[] b = cw.toByteArray();
	// can define or write to file:
	// defineClass(name, b, 0, b.length)
	// from findClass() in subclass of ClassLoader

	FileOutputStream fos = new FileOutputStream("Nerd.class");
	fos.write(b);
	fos.close();
}
 

/**
 * 生成格式如下的代码，其中ServiceInit_xxx由注解生成器生成。
 * <pre>
 * package com.sankuai.waimai.router.generated;
 *
 * public class ServiceLoaderInit {
 *
 *     public static void init() {
 *         ServiceInit_xxx1.init();
 *         ServiceInit_xxx2.init();
 *     }
 * }
 * </pre>
 */
private void generateServiceInitClass(String directory, Set<String> classes) {

    if (classes.isEmpty()) {
        WMRouterLogger.info(GENERATE_INIT + "skipped, no service found");
        return;
    }

    try {
        WMRouterLogger.info(GENERATE_INIT + "start...");
        long ms = System.currentTimeMillis();

        ClassWriter writer = new ClassWriter(ClassWriter.COMPUTE_FRAMES | ClassWriter.COMPUTE_MAXS);
        ClassVisitor cv = new ClassVisitor(Opcodes.ASM5, writer) {
        };
        String className = Const.SERVICE_LOADER_INIT.replace('.', '/');
        cv.visit(50, Opcodes.ACC_PUBLIC, className, null, "java/lang/Object", null);

        MethodVisitor mv = cv.visitMethod(Opcodes.ACC_PUBLIC | Opcodes.ACC_STATIC,
                Const.INIT_METHOD, "()V", null, null);

        mv.visitCode();

        for (String clazz : classes) {
            mv.visitMethodInsn(Opcodes.INVOKESTATIC, clazz.replace('.', '/'),
                    "init",
                    "()V",
                    false);
        }
        mv.visitMaxs(0, 0);
        mv.visitInsn(Opcodes.RETURN);
        mv.visitEnd();
        cv.visitEnd();

        File dest = new File(directory, className + SdkConstants.DOT_CLASS);
        dest.getParentFile().mkdirs();
        new FileOutputStream(dest).write(writer.toByteArray());

        WMRouterLogger.info(GENERATE_INIT + "cost %s ms", System.currentTimeMillis() - ms);

    } catch (IOException e) {
        WMRouterLogger.fatal(e);
    }
}
 

public void driveVisitor(Element fullElement, ClassVisitor visitor) {
  fullElement.accept(new ElementVisitorAdapter(), visitor);
  visitor.visitEnd();
}