// for plugin OpKernel developer's convenience.

#define C_OPKERNELCONTEXT_REQUIRES_OK(CTX, C_STATUS, __VA_ARGS__) \
  do {                                                            \
    ::tensorflow::Status _s(__VA_ARGS__);                         \
    if (!TF_PREDICT_TRUE(_s.ok())) {                              \
      ::tensorflow::Set_TF_Status_from_Status(C_STATUS, _s);      \

#define LIST_CASE(field, attr_type, ...)              \
  if (attr->list().field##_size() > 0) {              \
    metadata.type = attr_type;                        \
    metadata.list_size = attr->list().field##_size(); \
    __VA_ARGS__;                                      \
    break;                                            \
  }

      LIST_CASE(
          s, TF_ATTR_STRING, metadata.total_size = 0;