Method operator()

python/pyarrow/src/arrow/python/udf.cc:115–129

      : function_maker(std::move(function_maker)), cb(std::move(cb)) {}

  Result<std::unique_ptr<compute::KernelState>> operator()(
      compute::KernelContext* ctx, const compute::KernelInitArgs&) {
    return SafeCallIntoPython(
        [this, ctx]() -> Result<std::unique_ptr<compute::KernelState>> {
          UdfContext udf_context{ctx->memory_pool(), /*batch_length=*/0};
          OwnedRef empty_tuple(PyTuple_New(0));
          auto function = std::make_shared<OwnedRefNoGIL>(
              cb(function_maker->obj(), udf_context, empty_tuple.obj()));
          RETURN_NOT_OK(CheckPyError());
          if (!PyCallable_Check(function->obj())) {
            return Status::TypeError("Expected a callable Python object.");
          }
          return std::make_unique<PythonUdfKernelState>(std::move(function));
        });
  }

  std::shared_ptr<OwnedRefNoGIL> function_maker;
  UdfWrapperCallback cb;