struct ObjectClearer {
    void operator()(PyObject *obj) {
        Py_XDECREF(obj);
    }
};

typedef ::std::unique_ptr<PyObject, ObjectClearer> unique_object;


PyObject *ReadSharedMemory(PyObject *self, PyObject *args) {
    PyObject *agent_capsule = NULL;
    int worker_index;

    if (!PyArg_ParseTuple(args, "Oi", &agent_capsule, &worker_index)) {
        PyErr_BadArgument();
        return NULL;
    }

    SharedRingBufferAgent *agent = static_cast<SharedRingBufferAgent *>(
                        PyCapsule_GetPointer(agent_capsule, NULL));

    auto* buffer = agent->get_ring_buffer(static_cast<uint32_t>(worker_index));
    uint32_t msg_len = buffer->HeadMsgLen();

    std::unique_ptr<uint8_t[]> buf(new (std::nothrow) uint8_t[msg_len]);
    bool result = buffer->Read(buf.get());

    if (!result) {
        return Py_None;
    }

    struct TaskInfo* task_info = (struct TaskInfo*)(buf.get());
    unique_object msg(baidu::rpc::CreateMessage());

    uint32_t data_len = msg_len - sizeof(struct TaskInfo);
    uint8_t* data_ptr = buf.get() + sizeof(struct TaskInfo);

#if PY_MAJOR_VERSION >= 3
    unique_object req_buf(
        PyMemoryView_FromMemory(
                reinterpret_cast<char *>(data_ptr),
                static_cast<Py_ssize_t>(data_len),
                PyBUF_READ));
#else
    unique_object req_buf(
            PyBuffer_FromMemory(
                    data_ptr,
                    static_cast<Py_ssize_t>(data_len)));
#endif

    PyObject_SetAttrString(msg.get(), "_request_buf", req_buf.get());

    unique_object task_id(PyLong_FromLong(task_info->task_id));
    PyObject_SetAttrString(msg.get(), "_task_id", task_id.get());

    unique_object index(PyLong_FromLong(worker_index));
    PyObject_SetAttrString(msg.get(), "_worker_index", index.get());

    buf.release();
    return msg.release();
}

class Message(object):
    def __init__(self):
        self._request_buf = None
        self._response = None
        self._cntl = None
        self._closure = None
        self._method_index = -1
        self._task_id = -1
        self._worker_index = -1