Getting the currently active widget?

Hello,

I'm working on the AT-SPI2 driver of brltty, and there is something we
are doing very oddly: finding out which widget is currently active.  At
the moment what we do is starting from the AT-SPI root, and recursively
look at children until we find one which is focused and has an active
parent. This is quite suboptimal when the desktop is quite loaded... Is
there a better way to do this?

Samuel