Properties interface enhancements

[Havoc Pennington]

Hi,

Rob Taylor wrote:
> I've actually long though that this could be pretty useful - unnecessary
> context switches aren't nice! (seriously, with this work to move AT-SPI
> to dbus, it'd be good if every ATK signal emission didn't result in a
> context switch when there's no AT's running). It'd be possible to remove
> the race condition by having the bus only return from AddMatch after
> it's informed all relevant connections of the new requirement (and got a
> return from those calls).
> 

This would be pretty complex to code, both in the bus daemon itself and 
in the application code. It seems simpler to have some way to keep track 
of what AT's are running, composite that info into a global bool flag 
"there are >0 AT's", and skip all the signals (and all other ATK work 
for that matter) if there are no AT's. i.e. use the "client 
registration" pattern.

It would be nice to have some protocol and/or binding support for that 
pattern, for sure.

Havoc