[PATCH 1/3] libcamera: v4l2: Support fromEntityName with shared_ptr<MediaDevice>

[Laurent Pinchart]

Hi Paul,

Thank you for the patch.

On Fri, Apr 04, 2025 at 04:46:21PM +0900, Paul Elder wrote:
> From: Kieran Bingham <kieran.bingham at ideasonboard.com>
> 
> To facilitate expanding the use of a shared_ptr<MediaDevice> in
> preference of a raw MediaDevice* pointer, add an additional
> implementation for fromEntityName for both of v4l2_videodevice and
> v4l2_subdevice to support this type.

Is this really worth it, to just avoid a .get() call in the caller ?

> Signed-off-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
> Signed-off-by: Paul Elder <paul.elder at ideasonboard.com>
> ---
>  include/libcamera/internal/v4l2_subdevice.h   |  2 ++
>  include/libcamera/internal/v4l2_videodevice.h |  2 ++
>  src/libcamera/v4l2_subdevice.cpp              | 15 +++++++++++++++
>  src/libcamera/v4l2_videodevice.cpp            | 15 +++++++++++++++
>  4 files changed, 34 insertions(+)
> 
> diff --git a/include/libcamera/internal/v4l2_subdevice.h b/include/libcamera/internal/v4l2_subdevice.h
> index fa2a4a21eefb..08216cd56bc3 100644
> --- a/include/libcamera/internal/v4l2_subdevice.h
> +++ b/include/libcamera/internal/v4l2_subdevice.h
> @@ -163,6 +163,8 @@ public:
>  
>  	static std::unique_ptr<V4L2Subdevice>
>  	fromEntityName(const MediaDevice *media, const std::string &entity);
> +	static std::unique_ptr<V4L2Subdevice>
> +	fromEntityName(std::shared_ptr<const MediaDevice>, const std::string &entity);
>  
>  protected:
>  	std::string logPrefix() const override;
> diff --git a/include/libcamera/internal/v4l2_videodevice.h b/include/libcamera/internal/v4l2_videodevice.h
> index ae6a76cb0209..e35fb11bc99f 100644
> --- a/include/libcamera/internal/v4l2_videodevice.h
> +++ b/include/libcamera/internal/v4l2_videodevice.h
> @@ -228,6 +228,8 @@ public:
>  
>  	static std::unique_ptr<V4L2VideoDevice>
>  	fromEntityName(const MediaDevice *media, const std::string &entity);
> +	static std::unique_ptr<V4L2VideoDevice>
> +	fromEntityName(std::shared_ptr<const MediaDevice>, const std::string &entity);
>  
>  	V4L2PixelFormat toV4L2PixelFormat(const PixelFormat &pixelFormat) const;
>  
> diff --git a/src/libcamera/v4l2_subdevice.cpp b/src/libcamera/v4l2_subdevice.cpp
> index 33279654db8c..13f5316a3fc3 100644
> --- a/src/libcamera/v4l2_subdevice.cpp
> +++ b/src/libcamera/v4l2_subdevice.cpp
> @@ -1766,6 +1766,21 @@ V4L2Subdevice::fromEntityName(const MediaDevice *media,
>  	return std::make_unique<V4L2Subdevice>(mediaEntity);
>  }
>  
> +/**
> + * \brief Create a new video subdevice instance from \a entity in media device
> + * \a media
> + * \param[in] media The media device where the entity is registered
> + * \param[in] entity The media entity name
> + *
> + * \return A newly created V4L2Subdevice on success, nullptr otherwise
> + */
> +std::unique_ptr<V4L2Subdevice>
> +V4L2Subdevice::fromEntityName(std::shared_ptr<const MediaDevice> media,
> +			      const std::string &entity)
> +{
> +	return fromEntityName(media.get(), entity);
> +}
> +
>  std::string V4L2Subdevice::logPrefix() const
>  {
>  	return "'" + entity_->name() + "'";
> diff --git a/src/libcamera/v4l2_videodevice.cpp b/src/libcamera/v4l2_videodevice.cpp
> index f5b3fa09d9a0..ce7be7deb91f 100644
> --- a/src/libcamera/v4l2_videodevice.cpp
> +++ b/src/libcamera/v4l2_videodevice.cpp
> @@ -2109,6 +2109,21 @@ V4L2VideoDevice::fromEntityName(const MediaDevice *media,
>  	return std::make_unique<V4L2VideoDevice>(mediaEntity);
>  }
>  
> +/**
> + * \brief Create a new video device instance from \a entity in media device
> + * \a media
> + * \param[in] media The media device where the entity is registered
> + * \param[in] entity The media entity name
> + *
> + * \return A newly created V4L2VideoDevice on success, nullptr otherwise
> + */
> +std::unique_ptr<V4L2VideoDevice>
> +V4L2VideoDevice::fromEntityName(std::shared_ptr<const MediaDevice> media,
> +				const std::string &entity)
> +{
> +	return fromEntityName(media.get(), entity);
> +}
> +
>  /**
>   * \brief Convert \a PixelFormat to a V4L2PixelFormat supported by the device
>   * \param[in] pixelFormat The PixelFormat to convert

-- 
Regards,

Laurent Pinchart