[PATCH v1 3/4] libcamera: controls: Arrays of arrays are not supported

[Laurent Pinchart]

On Tue, Apr 01, 2025 at 03:19:38PM +0200, Barnabás Pőcze wrote:
> Arrays of arrays, even arrays of strings, are not supported by
> the current `ControlValue` mechanism, so disable them to trigger
> comptime errors if attempts are made to use them.

What currently happens if we try to use them ?

> Signed-off-by: Barnabás Pőcze <barnabas.pocze at ideasonboard.com>
> ---
>  include/libcamera/controls.h    | 2 +-
>  src/apps/cam/capture_script.cpp | 4 ----
>  2 files changed, 1 insertion(+), 5 deletions(-)
> 
> diff --git a/include/libcamera/controls.h b/include/libcamera/controls.h
> index d35347f4c..85c724ec1 100644
> --- a/include/libcamera/controls.h
> +++ b/include/libcamera/controls.h
> @@ -120,7 +120,7 @@ struct control_type<Point> {
>  };
>  
>  template<typename T, std::size_t N>
> -struct control_type<Span<T, N>> : public control_type<std::remove_cv_t<T>> {
> +struct control_type<Span<T, N>, std::enable_if_t<control_type<std::remove_cv_t<T>>::size == 0>> : public control_type<std::remove_cv_t<T>> {
>  	static constexpr std::size_t size = N;
>  };
>  
> diff --git a/src/apps/cam/capture_script.cpp b/src/apps/cam/capture_script.cpp
> index fc1dfa75f..f3262af98 100644
> --- a/src/apps/cam/capture_script.cpp
> +++ b/src/apps/cam/capture_script.cpp
> @@ -600,10 +600,6 @@ ControlValue CaptureScript::parseArrayControl(const ControlId *id,
>  		value = Span<const float>(values.data(), values.size());
>  		break;
>  	}
> -	case ControlTypeString: {
> -		value = Span<const std::string>(repr.data(), repr.size());
> -		break;
> -	}
>  	default:
>  		std::cerr << "Unsupported control type" << std::endl;
>  		break;

-- 
Regards,

Laurent Pinchart