Examples with Method org.objectweb.asm.commons.Method used on opensource projects

Example 31 with Method

use of org.objectweb.asm.commons.Method in project cdap by caskdata.

the class ContainerLauncherGenerator method generateMainClass.

/**
   * Generates a class that has a static main method which delegates the call to a static method in the given delegator
   * class with method signature {@code public static void launch(String className, String[] args)}
   *
   * @param className the classname of the generated class
   * @param mainDelegator the class to delegate the main call to
   * @param output for writing the generated bytes
   */
private static void generateMainClass(String className, Type mainDelegator, JarOutputStream output) throws IOException {
    String internalName = className.replace('.', '/');
    ClassWriter classWriter = new ClassWriter(ClassWriter.COMPUTE_FRAMES);
    classWriter.visit(Opcodes.V1_7, Opcodes.ACC_PUBLIC + Opcodes.ACC_SUPER, internalName, null, Type.getInternalName(Object.class), null);
    // Generate the default constructor, which just call super()
    Method constructor = Methods.getMethod(void.class, "<init>");
    GeneratorAdapter mg = new GeneratorAdapter(Opcodes.ACC_PUBLIC, constructor, null, null, classWriter);
    mg.loadThis();
    mg.invokeConstructor(Type.getType(Object.class), constructor);
    mg.returnValue();
    mg.endMethod();
    // Generate the main method
    // public static void main(String[] args) throws Exception {
    //   System.out.println("Launch class .....");
    //   <MainDelegator>.launch(<className>, args);
    // }
    Method mainMethod = Methods.getMethod(void.class, "main", String[].class);
    mg = new GeneratorAdapter(Opcodes.ACC_PUBLIC + Opcodes.ACC_STATIC, mainMethod, null, new Type[] { Type.getType(Exception.class) }, classWriter);
    mg.getStatic(Type.getType(System.class), "out", Type.getType(PrintStream.class));
    mg.visitLdcInsn("Launch class " + className + " by calling " + mainDelegator.getClassName() + ".launch");
    mg.invokeVirtual(Type.getType(PrintStream.class), Methods.getMethod(void.class, "println", String.class));
    // The main classname is stored as string literal in the generated class
    mg.visitLdcInsn(className);
    mg.loadArg(0);
    mg.invokeStatic(mainDelegator, Methods.getMethod(void.class, "launch", String.class, String[].class));
    mg.returnValue();
    mg.endMethod();
    classWriter.visitEnd();
    output.putNextEntry(new JarEntry(internalName + ".class"));
    output.write(classWriter.toByteArray());
}

Example 32 with Method

use of org.objectweb.asm.commons.Method in project cdap by caskdata.

the class SparkClassRewriter method rewriteExecutorClassLoader.

/**
   * Rewrites the ExecutorClassLoader so that it won't use system classloader as parent since CDAP classes
   * are not in system classloader.
   * Also optionally overrides the getResource, getResources and getResourceAsStream methods if they are not
   * defined (for fixing SPARK-11818 for older Spark < 1.6).
   */
private byte[] rewriteExecutorClassLoader(InputStream byteCodeStream) throws IOException {
    ClassReader cr = new ClassReader(byteCodeStream);
    ClassWriter cw = new ClassWriter(ClassWriter.COMPUTE_MAXS);
    final Type classloaderType = Type.getType(ClassLoader.class);
    final Type parentClassLoaderType = Type.getObjectType("org/apache/spark/util/ParentClassLoader");
    final Method parentLoaderMethod = new Method("parentLoader", parentClassLoaderType, new Type[0]);
    // Map from getResource* methods to the method signature
    // (can be null, since only method that has generic has signature)
    final Map<Method, String> resourceMethods = new HashMap<>();
    Method method = new Method("getResource", Type.getType(URL.class), new Type[] { Type.getType(String.class) });
    resourceMethods.put(method, null);
    method = new Method("getResources", Type.getType(Enumeration.class), new Type[] { Type.getType(String.class) });
    resourceMethods.put(method, Signatures.getMethodSignature(method, new TypeToken<Enumeration<URL>>() {
    }, TypeToken.of(String.class)));
    method = new Method("getResourceAsStream", Type.getType(InputStream.class), new Type[] { Type.getType(String.class) });
    resourceMethods.put(method, null);
    cr.accept(new ClassVisitor(Opcodes.ASM5, cw) {

        private boolean hasParentLoader;

        private boolean rewriteInit;

        @Override
        public void visit(int version, int access, String name, String signature, String superName, String[] interfaces) {
            // Only rewrite `<init>` if the ExecutorClassloader extends from ClassLoader
            if (classloaderType.getInternalName().equals(superName)) {
                rewriteInit = true;
            }
            super.visit(version, access, name, signature, superName, interfaces);
        }

        @Override
        public MethodVisitor visitMethod(int access, String name, String desc, String signature, String[] exceptions) {
            MethodVisitor mv = super.visitMethod(access, name, desc, signature, exceptions);
            // If the resource method is declared, no need to generate at the end.
            Method method = new Method(name, desc);
            resourceMethods.remove(method);
            hasParentLoader = hasParentLoader || parentLoaderMethod.equals(method);
            if (!rewriteInit || !"<init>".equals(name)) {
                return mv;
            }
            return new GeneratorAdapter(Opcodes.ASM5, mv, access, name, desc) {

                @Override
                public void visitMethodInsn(int opcode, String owner, String name, String desc, boolean itf) {
                    // If there is a call to `super()`, skip that instruction and have the onMethodEnter generate the call
                    if (opcode == Opcodes.INVOKESPECIAL && Type.getObjectType(owner).equals(classloaderType) && name.equals("<init>") && Type.getArgumentTypes(desc).length == 0 && Type.getReturnType(desc).equals(Type.VOID_TYPE)) {
                        // Generate `super(null)`. The `this` is already in the stack, so no need to `loadThis()`
                        push((Type) null);
                        invokeConstructor(classloaderType, new Method("<init>", Type.VOID_TYPE, new Type[] { classloaderType }));
                    } else {
                        super.visitMethodInsn(opcode, owner, name, desc, itf);
                    }
                }
            };
        }

        @Override
        public void visitEnd() {
            // All implementations are delegating to the parentLoader
            if (!hasParentLoader) {
                super.visitEnd();
                return;
            }
            for (Map.Entry<Method, String> entry : resourceMethods.entrySet()) {
                // Generate the method.
                // return parentLoader().getResource*(arg)
                Method method = entry.getKey();
                MethodVisitor mv = super.visitMethod(Modifier.PUBLIC, method.getName(), method.getDescriptor(), entry.getValue(), null);
                GeneratorAdapter generator = new GeneratorAdapter(Modifier.PUBLIC, method, mv);
                // call `parentLoader()`
                generator.loadThis();
                generator.invokeVirtual(SPARK_EXECUTOR_CLASSLOADER_TYPE, parentLoaderMethod);
                // Load the argument
                generator.loadArg(0);
                // Call the method on the parent loader.
                generator.invokeVirtual(parentClassLoaderType, method);
                generator.returnValue();
                generator.endMethod();
            }
        }
    }, ClassReader.EXPAND_FRAMES);
    return cw.toByteArray();
}