[libcamera-devel] [RFC 3/7] libcamera: camera_sensor: Factorize out properties

[Niklas Söderlund]

Hi Jacopo,

Thanks for your patch.

On 2019-12-18 15:49:57 +0100, Jacopo Mondi wrote:
> Factorize CameraSensor properties initialization to a dedicated virtual

Factorize don't seem to match the context :-)

I would here and in the subject s/Factorize/Refactor/

> function that dervied classes could subclass to register sensor-specific
> properties.
> 
> Signed-off-by: Jacopo Mondi <jacopo at jmondi.org>
> ---
>  src/libcamera/camera_sensor.cpp       | 94 ++++++++++++++++-----------
>  src/libcamera/include/camera_sensor.h |  5 +-
>  2 files changed, 60 insertions(+), 39 deletions(-)
> 
> diff --git a/src/libcamera/camera_sensor.cpp b/src/libcamera/camera_sensor.cpp
> index d1c9c9bcd58f..9692895d9b7b 100644
> --- a/src/libcamera/camera_sensor.cpp
> +++ b/src/libcamera/camera_sensor.cpp
> @@ -77,7 +77,7 @@ CameraSensor *CameraSensorFactory::create(const MediaEntity *entity)
>   * Once constructed the instance must be initialized with init().
>   */
>  CameraSensor::CameraSensor(const MediaEntity *entity)
> -	: entity_(entity), properties_(properties::properties)
> +	: properties_(properties::properties), entity_(entity)
>  {
>  	subdev_ = new V4L2Subdevice(entity);
>  }
> @@ -119,42 +119,6 @@ int CameraSensor::init()
>  	if (ret < 0)
>  		return ret;
>  
> -	/* Retrieve and store the camera sensor properties. */
> -	const ControlInfoMap &controls = subdev_->controls();
> -	int32_t propertyValue;
> -
> -	/* Camera Location: default is front location. */
> -	const auto &locationControl = controls.find(V4L2_CID_CAMERA_SENSOR_LOCATION);
> -	if (locationControl != controls.end()) {
> -		int32_t v4l2Location =
> -			locationControl->second.def().get<int32_t>();
> -		switch (v4l2Location) {
> -		case V4L2_LOCATION_EXTERNAL:
> -			propertyValue = properties::CameraLocationExternal;
> -			break;
> -		case V4L2_LOCATION_FRONT:
> -			propertyValue = properties::CameraLocationFront;
> -			break;
> -		case V4L2_LOCATION_BACK:
> -			propertyValue = properties::CameraLocationBack;
> -			break;
> -		default:
> -			LOG(CameraSensor, Error)
> -				<< "Unsupported camera location: " << v4l2Location;
> -			return -EINVAL;
> -		}
> -	} else {
> -		propertyValue = properties::CameraLocationFront;
> -	}
> -	properties_.set(properties::Location, propertyValue);
> -
> -	/* Camera Rotation: default is 0 degrees. */
> -	propertyValue = 0;
> -	const auto &rotationControl = controls.find(V4L2_CID_CAMERA_SENSOR_ROTATION);
> -	if (rotationControl != controls.end())
> -		propertyValue = rotationControl->second.def().get<int32_t>();
> -	properties_.set(properties::Rotation, propertyValue);
> -

I Wonder if we should not refactor this into three functions, one 
virtual initProperties() as done already but go even further and add a 
two non-virtual functions initDefaultLocationProperty() and 
initDefaultRotationProperty().

The refactored initProperties() would then call the two new functions 
and allow subclasses to reuse a standard way to parse common 
controls/properties.

>  	/* Enumerate and cache media bus codes and sizes. */
>  	const ImageFormats formats = subdev_->formats(0);
>  	if (formats.isEmpty()) {
> @@ -185,6 +149,62 @@ int CameraSensor::init()
>  	std::sort(mbusCodes_.begin(), mbusCodes_.end());
>  	std::sort(sizes_.begin(), sizes_.end());
>  
> +	return initProperties(subdev_->controls());
> +}
> +
> +/**
> + * \brief Initialize the camera sensor properties
> + * \param[in] controlMap The map of control information provided by the sensor
> + *
> + * This method initializes the camera sensor properties, by inspecting the
> + * control information reported by the sensor media entity in \a controlMap.
> + * For each supported standard V4L2 control reported by the sensor, a libcamera
> + * property is created and registered in the list of properties supported by the
> + * sensor.
> + *
> + * Derived classes are free to override this method to register sensor specific
> + * properties as they like, by inspecting custom controls or by adding
> + * properties with pre-defined values, and eventually call this base class
> + * implementation to register standard ones.
> + *
> + * \return 0 on success, a negative error code otherwise
> + */
> +int CameraSensor::initProperties(const ControlInfoMap &controlMap)
> +{
> +	int32_t propertyValue;
> +
> +	/* Camera Location: default is front location. */
> +	const auto &locationControl = controlMap.find(V4L2_CID_CAMERA_SENSOR_LOCATION);
> +	if (locationControl != controlMap.end()) {
> +		int32_t v4l2Location =
> +			locationControl->second.def().get<int32_t>();
> +		switch (v4l2Location) {
> +		case V4L2_LOCATION_EXTERNAL:
> +			propertyValue = properties::CameraLocationExternal;
> +			break;
> +		case V4L2_LOCATION_FRONT:
> +			propertyValue = properties::CameraLocationFront;
> +			break;
> +		case V4L2_LOCATION_BACK:
> +			propertyValue = properties::CameraLocationBack;
> +			break;
> +		default:
> +			LOG(CameraSensor, Error)
> +				<< "Unsupported camera location: " << v4l2Location;
> +			return -EINVAL;
> +		}
> +	} else {
> +		propertyValue = properties::CameraLocationFront;
> +	}
> +	properties_.set(properties::Location, propertyValue);
> +
> +	/* Camera Rotation: default is 0 degrees. */
> +	propertyValue = 0;
> +	const auto &rotationControl = controlMap.find(V4L2_CID_CAMERA_SENSOR_ROTATION);
> +	if (rotationControl != controlMap.end())
> +		propertyValue = rotationControl->second.def().get<int32_t>();
> +	properties_.set(properties::Rotation, propertyValue);
> +
>  	return 0;
>  }
>  
> diff --git a/src/libcamera/include/camera_sensor.h b/src/libcamera/include/camera_sensor.h
> index 2c09b1bdb61b..43748a6c8535 100644
> --- a/src/libcamera/include/camera_sensor.h
> +++ b/src/libcamera/include/camera_sensor.h
> @@ -38,6 +38,7 @@ public:
>  	CameraSensor &operator=(const CameraSensor &) = delete;
>  
>  	int init();
> +	virtual int initProperties(const ControlInfoMap &controlMap);
>  
>  	const MediaEntity *entity() const { return entity_; }
>  	const std::vector<unsigned int> &mbusCodes() const { return mbusCodes_; }
> @@ -55,6 +56,8 @@ public:
>  	const ControlList &properties() const { return properties_; }
>  
>  protected:
> +	ControlList properties_;
> +
>  	friend class CameraSensorFactory;
>  	explicit CameraSensor(const MediaEntity *entity);
>  	std::string logPrefix() const;
> @@ -65,8 +68,6 @@ private:
>  
>  	std::vector<unsigned int> mbusCodes_;
>  	std::vector<Size> sizes_;
> -
> -	ControlList properties_;
>  };
>  
>  } /* namespace libcamera */
> -- 
> 2.24.0
> 
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-- 
Regards,
Niklas Söderlund