[PATCH libinput 9/9] Add libinput_device_get_name() to advertise the kernel name

[Peter Hutterer]

On Tue, Apr 08, 2014 at 10:22:23PM +0200, Jonas Ådahl wrote:
> On Fri, Mar 28, 2014 at 02:38:52PM +1000, Peter Hutterer wrote:
> > Signed-off-by: Peter Hutterer <peter.hutterer at who-t.net>
> > ---
> 
> Sorry, had forgotten about these, but have some comments (in a previous
> e-mail and in this one). Anyhow, consider the patches in this series
> Reviewed-by: me.
> 
> > I didn't end up needing this but it seems a nice to have. However, it does
> > lead to a discussion on how much of the device should we expose to the
> > caller through libinput.
> 
> Is it really needed to start exposing information without existing use
> cases using them?
> 
> In this case, its already useful in event-debug, so it makes sense to
> add immediately.

my argument here is largely: if we expose some information this way, we
will eventually need to expose everything this way (fsvo "everything"). if
we have some other way, like the fd approach you mentioned below, we don't
need to expose any of it. any other approach means more boilerplate code in
the client, so the question is where should we draw the line, or plan to
draw the line?

> > Right now libinput hides virtually everthing but the sysname and even that
> > may not be enough to even get a udev reference. It is enough for now though
> > because we only handle one subsystem.
> > 
> > If a caller needs settings or get other information on the device, they need
> > to be able to query udev or the fd, but the latter then needs 
> > needs open_restricted-like hooks.
> 
> Maybe libinput could allow reopening a device returning a new fd. Not a
> dup() but using the already existing open_restricted hooks in libinput
> internally to open a new fd.

hmm, interesting idea. I'll have a think about that. the other option could
be to export the dev_t, which also provides an easy way to get to the
device, either through udev or manually.
 
> >  src/libinput.c      |  6 ++++++
> >  src/libinput.h      | 12 ++++++++++++
> >  tools/event-debug.c |  5 +++--
> >  3 files changed, 21 insertions(+), 2 deletions(-)
> > 
> > diff --git a/src/libinput.c b/src/libinput.c
> > index 1e31be3..2863f1d 100644
> > --- a/src/libinput.c
> > +++ b/src/libinput.c
> > @@ -1043,6 +1043,12 @@ libinput_device_get_user_data(struct libinput_device *device)
> >  }
> >  
> >  LIBINPUT_EXPORT const char *
> > +libinput_device_get_name(struct libinput_device *device)
> > +{
> > +	return ((struct evdev_device *) device)->devname;
> > +}
> > +
> > +LIBINPUT_EXPORT const char *
> >  libinput_device_get_sysname(struct libinput_device *device)
> >  {
> >  	return evdev_device_get_sysname((struct evdev_device *) device);
> > diff --git a/src/libinput.h b/src/libinput.h
> > index 6e43181..f291ce8 100644
> > --- a/src/libinput.h
> > +++ b/src/libinput.h
> > @@ -1158,6 +1158,18 @@ libinput_device_get_user_data(struct libinput_device *device);
> >  /**
> >   * @ingroup device
> >   *
> > + * Get the name of the device.
> 
> Maybe mention that the name is descriptive and in human readable form
> i.e. not enumerated device name on the filesystem.

will do, thanks.

Cheers,
  Peter

> > + *
> > + * @param device A previously obtained device
> > + * @return The product name of the device
> > + *
> > + */
> > +const char*
> > +libinput_device_get_name(struct libinput_device *device);
> > +
> > +/**
> > + * @ingroup device
> > + *
> >   * Get the system name of the device.
> >   *
> >   * @param device A previously obtained device
> > diff --git a/tools/event-debug.c b/tools/event-debug.c
> > index c0a08a7..3d0a383 100644
> > --- a/tools/event-debug.c
> > +++ b/tools/event-debug.c
> > @@ -231,9 +231,10 @@ print_device_notify(struct libinput_event *ev)
> >  	struct libinput_device *dev = libinput_event_get_device(ev);
> >  	struct libinput_seat *seat = libinput_device_get_seat(dev);
> >  
> > -	printf("%s	%s\n",
> > +	printf("%s	%s	%s\n",
> >  	       libinput_seat_get_physical_name(seat),
> > -	       libinput_seat_get_logical_name(seat));
> > +	       libinput_seat_get_logical_name(seat),
> > +	       libinput_device_get_name(dev));
> >  }
> >  
> >  static void
> > -- 
> > 1.8.5.3
> > 
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