Previously we had ei_seat.capabilities and ei_device.capabilities,
both referring to the same enum. The seat caps were used to bind,
the device caps were used to announce capabilities.
The device caps were already mostly superfluous as the information
they carried was implicitly available by the set of interfaces
the device announced - if the device has a keyboard interface
it must also have the keyboard capability.
So let's drop the separate enum and make the capabilities
the set of supported interfaces. In the device we can drop the
event directly and just send the interface list. In the seat
we have a capability event that sends each *possible* interface
with a custom-assigned mask. The client can then use that mask
to bind to the capability as before.
For example:
<- ei_seat.capability(0x1, "ei_pointer")
<- ei_seat.capability(0x4, "ei_keyboard")
<- ei_seat.capability(0x8, "ei_touchscreen")
<- ei_seat.done()
-> ei_seat.bind(0x4 | 0x8) # bind to keyboard and touchscreen
<- ei_seat.device()
-> ei_device.interface("ei_keyboard")
-> ei_device.interface("ei_touchscreen")
<- ei_device.done()
In the generated bindings we simply use the interface index
to generate the masks, but the protocol at least states that
the mask may not be constant.
Because the button/scroll interfaces are not exposed by the C API, some
of the handling is a bit awkward since we need to use both depending
whether we have pointer/pointer_absolute selected.
Fixes#28
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Split the ei_pointer protocol interface into ei_pointer,
ei_pointer_absolute, ei_scroll and ei_button.
This gets rid of the slightly awkward pointer vs pointer absolute
handling. Those were two different capabilities but tied to the same
interface.
Plus it paves the way for devices that are keyboards with scroll
buttons, etc.
This allows us to have a device support multiple interfaces and evolve
those interfaces individually, e.g. add things to the keyboard interface
without having to bump the touchscreen interface.
Note that due to a name clash with the existing struct ei_touch public
API the protocol interface is named touchscreen.
