[libcamera-devel] [PATCH 07/17] libcamera: v4l2_subdevice: Rework enumPadSizes()

[Jacopo Mondi]

Hi Niklas,

On Mon, May 27, 2019 at 02:15:33AM +0200, Niklas Söderlund wrote:
> Align the enumPadSizes() interface and implementation with that of
> enumPadCodes(). There is no functional change.
>

I'm afraid there are a few :)

> Signed-off-by: Niklas Söderlund <niklas.soderlund at ragnatech.se>
> ---
>  src/libcamera/include/v4l2_subdevice.h |  4 +--
>  src/libcamera/v4l2_subdevice.cpp       | 36 ++++++++++++--------------
>  2 files changed, 19 insertions(+), 21 deletions(-)
>
> diff --git a/src/libcamera/include/v4l2_subdevice.h b/src/libcamera/include/v4l2_subdevice.h
> index e714e2575022c04d..c6fdf417b43c0423 100644
> --- a/src/libcamera/include/v4l2_subdevice.h
> +++ b/src/libcamera/include/v4l2_subdevice.h
> @@ -58,8 +58,8 @@ protected:
>
>  private:
>  	std::vector<unsigned int> enumPadCodes(unsigned int pad);
> -	int enumPadSizes(unsigned int pad, unsigned int code,
> -			 std::vector<SizeRange> *size);
> +	std::vector<SizeRange> enumPadSizes(unsigned int pad,
> +					    unsigned int code);
>
>  	int setSelection(unsigned int pad, unsigned int target,
>  			 Rectangle *rect);
> diff --git a/src/libcamera/v4l2_subdevice.cpp b/src/libcamera/v4l2_subdevice.cpp
> index 51b0ffaafb3e668e..8720013600ddb95f 100644
> --- a/src/libcamera/v4l2_subdevice.cpp
> +++ b/src/libcamera/v4l2_subdevice.cpp
> @@ -210,8 +210,7 @@ FormatEnum V4L2Subdevice::formats(unsigned int pad)
>  	}
>
>  	for (unsigned int code : enumPadCodes(pad))
> -		if (enumPadSizes(pad, code, &formatMap[code]))
> -			return {};
> +		formatMap[code] = enumPadSizes(pad, code);
>
>  	return formatMap;
>  }
> @@ -336,38 +335,37 @@ std::vector<unsigned int> V4L2Subdevice::enumPadCodes(unsigned int pad)
>  	return codes;
>  }
>
> -int V4L2Subdevice::enumPadSizes(unsigned int pad,unsigned int code,
> -				std::vector<SizeRange> *sizes)
> +std::vector<SizeRange> V4L2Subdevice::enumPadSizes(unsigned int pad,
> +						   unsigned int code)

One of the reason I returned an int and accepted the vector as
parameter, was to be able to propagate up any error returned by
ENUM_FRAME_SIZES which is here ignored instead (not true, a message is
printed out) leaving the format map with an entry with an empty size
list.

If you're confortable with not propagating the error up, which I agree
might not be that -strictly- vital, at least you should check if the
returned vector is empty and not add the format code to the map. This
means you should store the size list in a local variable first, then
copy it in the map, giving up  any return value optimization speed
up. This was the reason this code returned an int.

Thanks
   j

>  {
> -	struct v4l2_subdev_frame_size_enum sizeEnum = {};
> +	std::vector<SizeRange> sizes;
>  	int ret;
>
> -	sizeEnum.index = 0;
> -	sizeEnum.pad = pad;
> -	sizeEnum.code = code;
> -	sizeEnum.which = V4L2_SUBDEV_FORMAT_ACTIVE;
> -	while (true) {
> +	for (unsigned int index = 0;; index++) {
> +		struct v4l2_subdev_frame_size_enum sizeEnum = {
> +			.index = index,
> +			.pad = pad,
> +			.code = code,
> +			.which = V4L2_SUBDEV_FORMAT_ACTIVE,
> +		};
> +
>  		ret = ioctl(fd_, VIDIOC_SUBDEV_ENUM_FRAME_SIZE, &sizeEnum);
>  		if (ret)
>  			break;
>
> -		sizes->emplace_back(sizeEnum.min_width, sizeEnum.min_height,
> +		sizes.emplace_back(sizeEnum.min_width, sizeEnum.min_height,
>  				    sizeEnum.max_width, sizeEnum.max_height);
> -
> -		sizeEnum.index++;
>  	}
>
>  	if (ret && (errno != EINVAL && errno != ENOTTY)) {
> -		ret = -errno;
> +		ret = errno;
>  		LOG(V4L2Subdev, Error)
>  			<< "Unable to enumerate sizes on pad " << pad
> -			<< ": " << strerror(-ret);
> -		sizes->clear();
> -
> -		return ret;
> +			<< ": " << strerror(ret);
> +		return {};
>  	}
>
> -	return 0;
> +	return sizes;
>  }
>
>  int V4L2Subdevice::setSelection(unsigned int pad, unsigned int target,
> --
> 2.21.0
>
> _______________________________________________
> libcamera-devel mailing list
> libcamera-devel at lists.libcamera.org
> https://lists.libcamera.org/listinfo/libcamera-devel
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