[Xcb] [PATCH 5/7] Add event queue splitting

[Josh Triplett]

On Wed, Nov 06, 2013 at 02:34:03PM -0500, Peter Harris wrote:
> On 2013-11-05 19:41, Keith Packard wrote:
> > This allows apps to peel off certain XGE events into separate queues
> > for custom handling. Designed to support the Present extension
> > 
> > Signed-off-by: Keith Packard <keithp at keithp.com>
> 
> Re: xcb_register_for_special_event, xcb_unregister_for_special_event,
> xcb_check_for_special_event, and xcb_wait_for_special_event.
> 
> There was some push-back the last time something similar to this came
> up, on the theory that it should be in a separate library from xcb[1].
> That said, we may have reached the point where it's just too useful to
> not have in libxcb.
> 
> Does this interface work for the rest of the things needed for GLX?

The last time that Jamey and I spoke about this, we agreed that this
type of mechanism would be required to make GL work, and that there's
really no other way to support it.  However, I'd like to see it not
XGE-specific, so that it could support the existing events GL needs
today, not just the new Present/DRI3 approach.

The architecture we'd discussed was effectively that it should be
possible to create one or more separate event queues from the primary
one, add filters that peel off events into those queues (which XCB will
automatically apply as events arrive), and then read the next event from
a queue.

- Josh Triplett