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

[Kieran Bingham]

Quoting Laurent Pinchart (2024-08-15 22:17:45)
> 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 ?

Ooops - I didn't look closely to check.

I'll update.

> 
> > +{
> > +     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();

That may as well complete the set! I expect MediaPad is also used as
strings elsewhere through the code base quite a lot so is likely to be
useful.

> 
> Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> 
> > +
> > +     return out;
> > +}
> > +
> >  /**
> >   * \fn MediaLink::source()
> >   * \brief Retrieve the link's source pad
> 
> -- 
> Regards,
> 
> Laurent Pinchart