[libcamera-devel] [PATCH v3 06/13] libcamera: stream: Add operator<<() to print StreamRole as a string

[Laurent Pinchart]

Hi Jacopo,

On Wed, Oct 26, 2022 at 05:07:03PM +0200, Jacopo Mondi wrote:
> On Mon, Oct 24, 2022 at 03:03:49AM +0300, Laurent Pinchart via libcamera-devel wrote:
> > libcamera prints stream role values in log messages. To be more
> > user-friendly, add a specialization of operator<<() to print the role
> > name as a string instead of a numerical value.
> >
> > Signed-off-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> 
> > ---
> >  include/libcamera/stream.h |  3 +++
> >  src/libcamera/stream.cpp   | 19 +++++++++++++++++++
> >  2 files changed, 22 insertions(+)
> >
> > diff --git a/include/libcamera/stream.h b/include/libcamera/stream.h
> > index f0ae7e62e0a3..efec695ad317 100644
> > --- a/include/libcamera/stream.h
> > +++ b/include/libcamera/stream.h
> > @@ -9,6 +9,7 @@
> >
> >  #include <map>
> >  #include <memory>
> > +#include <ostream>
> >  #include <string>
> >  #include <vector>
> >
> > @@ -70,6 +71,8 @@ enum StreamRole {
> >
> >  using StreamRoles = std::vector<StreamRole>;
> >
> > +std::ostream &operator<<(std::ostream &out, StreamRole role);
> > +
> >  class Stream
> >  {
> >  public:
> > diff --git a/src/libcamera/stream.cpp b/src/libcamera/stream.cpp
> > index 686e693bccba..67f308157fbf 100644
> > --- a/src/libcamera/stream.cpp
> > +++ b/src/libcamera/stream.cpp
> > @@ -417,6 +417,25 @@ std::string StreamConfiguration::toString() const
> >   * acceptable.
> >   */
> >
> > +/**
> > + * \brief Insert a text representation of a StreamRole into an output stream
> > + * \param[in] out The output stream
> > + * \param[in] role The StreamRole
> > + * \return The output stream \a out
> > + */
> > +std::ostream &operator<<(std::ostream &out, StreamRole role)
> > +{
> > +	static constexpr std::array<const char *, 4> names{
> > +		"Raw",
> > +		"StillCapture",
> > +		"VideoRecording",
> > +		"Viewfinder",
> > +	};
> 
> My only concern is about the enum and the list of names going out of
> sync. A map might help ?

I'm not very concerned by the risk of reordering values, I don't think
we will do that. There is a risk of forgetting to update this code when
adding values though, but I haven't found a goog way to catch this at
compilation time.

> > +
> > +	out << names[static_cast<std::underlying_type_t<StreamRole>>(role)];
> > +	return out;
> > +}
> > +
> >  /**
> >   * \typedef StreamRoles
> >   * \brief A vector of StreamRole

-- 
Regards,

Laurent Pinchart