[PATCH 1/3] libcamera: media_object: Add MediaLink string representations

[Laurent Pinchart]

Hi Kieran,

Thank you for the patch.

On Thu, Aug 15, 2024 at 10:09:23PM +0100, Kieran Bingham wrote:
> Various parts of libcamera print the representation of a MediaLink by
> inline joining the parts to make a string representation.
> 
> This repeated use case can be supported with a common helper to print
> the MediaLink in a common manner using the existing toString() and
> operator<< overload style to make it easier to report on MediaLink
> types.
> 
> This implementation will report in the following style:
> 
>   'imx283 1-001a'[0] -> 'video-mux'[0]
> 
> Signed-off-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
> ---
>  include/libcamera/internal/media_object.h |  4 ++++
>  src/libcamera/media_object.cpp            | 25 +++++++++++++++++++++++
>  2 files changed, 29 insertions(+)
> 
> diff --git a/include/libcamera/internal/media_object.h b/include/libcamera/internal/media_object.h
> index c9d77511a991..3ebef938bc49 100644
> --- a/include/libcamera/internal/media_object.h
> +++ b/include/libcamera/internal/media_object.h
> @@ -48,6 +48,8 @@ public:
>  	unsigned int flags() const { return flags_; }
>  	int setEnabled(bool enable);
>  
> +	std::string toString() const;
> +
>  private:
>  	LIBCAMERA_DISABLE_COPY_AND_MOVE(MediaLink)
>  
> @@ -61,6 +63,8 @@ private:
>  	unsigned int flags_;
>  };
>  
> +std::ostream &operator<<(std::ostream &out, const MediaLink &link);
> +
>  class MediaPad : public MediaObject
>  {
>  public:
> diff --git a/src/libcamera/media_object.cpp b/src/libcamera/media_object.cpp
> index 1b191a1e4df8..fa2c44b0abb6 100644
> --- a/src/libcamera/media_object.cpp
> +++ b/src/libcamera/media_object.cpp
> @@ -146,6 +146,31 @@ MediaLink::MediaLink(const struct media_v2_link *link, MediaPad *source,
>  {
>  }
>  
> +std::string MediaLink::toString() const

No warning from doxygen about missing documentation ?

> +{
> +	std::stringstream ss;
> +	ss << *this;
> +
> +	return ss.str();
> +}
> +
> +/**
> + * \brief Insert a text representation of a Link into an output stream
> + * \param[in] out The output stream
> + * \param[in] r The MediaLink
> + * \return The output stream \a out
> + */
> +std::ostream &operator<<(std::ostream &out, const MediaLink &link)
> +{
> +	out << "'"
> +	    << link.source()->entity()->name() << "'["
> +	    << link.source()->index() << "] -> '"
> +	    << link.sink()->entity()->name() << "'["
> +	    << link.sink()->index() << "]";

How about also adding the same two helpers for MediaPad ? Then you could
write

	out << link.source() << " -> " << link->sink();

Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>

> +
> +	return out;
> +}
> +
>  /**
>   * \fn MediaLink::source()
>   * \brief Retrieve the link's source pad

-- 
Regards,

Laurent Pinchart