When talking to other applications or serializing the modifier
state (and in particular when implementing a wayland compositor),
the effective modifier state alone is not sufficient, one needs
to know the base, latched and locked modifiers.
Previously one could do with backend specific functionality
such as clutter_device_manager_evdev_get_xkb_state(), but the
problem is that the internal data structures are updated as
soon as the events are fetched from the upstream source, but
the events are reported to the application some time later,
and thus the two can get out of sync.
This way, on the other hand, the information is cached in the
event, and provided to the application with the value that
was current when the event was generated.
https://bugzilla.gnome.org/show_bug.cgi?id=706494
All evdev devices are slave devices, which means that xkb state
and pointer position must be shared by emulating a core keyboard
and a core pointer. Also, we must make sure to add all modifier
state (keyboard and button) to our events.
https://bugzilla.gnome.org/show_bug.cgi?id=705710
For Wayland, this is mostly the input protocol having changed, although
there's also the SHM pool API, the cursor API, as well as fullscreen and
ping.
Also port to the new (months-old) xkbcommon API, as used by Weston 0.95.
This involves having xkbcommon manage the state for us, where
appropriate. Fans of multi-layout keyboards (or just caps lock) will no
doubt appreciate these changes.
Signed-off-by: Daniel Stone <daniel@fooishbar.org>
The wayland client code has support for translating raw linux input
device key codes coming from the wayland compositor into key symbols
thanks to libxkbcommon.
A backend directly listening to linux input devices (called evdev, just
like the Xorg one) could use exactly the same code for the translation,
so abstract it a bit in a separate file.
