Keyboard issues w/Orca screen reader

[Mike Gorse]

As part of the GNOME project, we have Orca. It is a screen reader that reads 
what an application is displaying out loud, or sends it to a Braille display. 
It allows a blind user to interact with GNOME. There are currently several 
issues with Orca on Wayland, since it (and AT-SPI, the accessibility API that 
it uses) were originally designed for X11, without regard to the kind of 
security constraints that Wayland has.

Traditionally, Orca has used what amounts to a key filter implemented by 
AT-SPI. The toolkit (gtk, qt, etc) would make a dbus method call to AT-SPI when 
a key is pressed, passing on the keycode, keysym, and text associated with the 
key (Orca uses the latter to announce the key that was just pressed). The 
AT-SPI registry daemon would make a method call to Orca, Orca would return a 
boolean to indicate whether it consumed the key or not, and AT-SPI would return 
the result to the toolkit. This is no longer supported by gtk 4, so I am trying 
to solve things another way. There is a good amount of discussion at 
https://gitlab.gnome.org/GNOME/gtk/-/issues/1739

Orca uses this key filter for a few things. It wants to announce the key that 
the user just pressed. If the user presses the control key, then Orca will stop 
reading whatever it is reading. It also implements commands in this way (the 
user can press a key to have it read the current line, to give one example). 
For X11, I can have AT-SPI/Orca watch for XI_KeyPress events and call 
XIGrabKeycode when Orca wants to grab a key, but I'm struggling to figure out 
what to do on Wayland. I think that I would need to propose a new protocol or 
two, but I foresee security being a challenge/concern, so I'm wondering if 
anyone has any advice in particular. Xwayland-keyboard-grab looks like it would 
do part of what I need, if Orca ran as an xwayland client, but it wouldn't help 
in terms of passing key press notifications on to Orca for the purposes of key 
echoing and interrupting speech, unless a grab was active for the particular 
key. If I enable my X11 code for Wayland, then I don't see XI_KeyPress events 
for keys going to other applications, which I think is expected given Wayland's 
security model.

Thanks,
-Mike