[Xevie] Discussion startin on this alias about changes to the X server event subsystem

[Deron Johnson]

We've decided to start a general discussion on this alias about
changes to the X server event subsystem.

I'm starting to design what I call an External Event Manager (EEM?)
extension to the X server. The purpose of this extension would be to
provide a mechanism and protocol which would allow an external event
manager client to access the input device event stream of the X
server, to perform its own event processing, and to reinsert
processed, high-level X events back into the X server for distribution
to X clients.  The motivation for this would be to support 3D window
systems which require more sophisticated event processing than what
core X provides.  Rather than shoehorning a complex 3D-oriented event
processing subsystem into the X server, the idea would be to tap into
the low-level device event stream, ship it to a process which knows
how what to do with these events, and then, if the events are bound
for an X client, to reinsert these processed events back into the X
server. This would effectively "shunt around" the existing event
processing of the X server (which starts are CoreProcessKeyboardEvent
and CoreProcessPointerEvent). When the X server is running with an
external event manager (almost) all of the processing which converts
input device events into high-level X11 events would be no-op'd out.

It might be that the functionality which I am talking about ends up
becoming an extension to XEVIE or it might end up as an extension in
its own right. I have thought about it enough to come to the
conclusion that the existing XEVIE extension, as specified, won't
suffice for what I need.