ATSPI over D-Bus (was Re: [Accessibility] Re: [Accessibility-atspi] D-Bus AT-SPI - The way forward)

Rob Taylor rob.taylor at
Wed Dec 12 15:14:39 PST 2007

Havoc Pennington wrote:
> Hi,
> Rob Taylor wrote:
>> CC'ing the D-Bus mailing list as there's lots of interesting stuff here.
> OK, this is about 400 topics in one email, cross-posted to 5 mailing
> lists ;-)

Heh, you can blame Michael for bringing such a long list of issues

<snip - we can get round to the other bits later>

> Perspective
> ===
> Let me say again. I know it's a lot of fun to screw with component
> systems and type systems and IPC systems. (Obviously I've done it
> myself.) However, we should not delude ourselves that this is especially
> *worthwhile* in most cases.
> Where are apps having the most trouble, doing the most things wrong,
> etc.? Arcane improvements to the IPC system are not the answer.

Havoc, these discussion aren't coming out of 'wouldn't it be fun to add
lots of stuff to dbus?' its out of 'here's an existing technology based
on a component technology, how can we use dbus for this case?'

Note that performance is really an issue here, have a look at the
current profiling breakdown of AT-SPI as it stands today:

> Most of the problems are on a higher level. e.g. lack of convenience API
> for stuff like this:
> Or in GNOME, we aren't even using dbus for the baseline, simple
> functionality it already provides; e.g. there's still no single-instance
> support in gtk. Why would we be adding all kinds of new stuff to dbus,
> when we're still sucking at using the functionality we have?

It would be good of you to take a look over the current work plan here,
to get a clearer idea of what's actually being planned.

> Let's remember that DCOP was implemented in a very short period of time,
> and was dead simple - MUCH less complex than dbus is - and people used
> it heavily and successfully for lots of real functionality.

And KDE never wrote a sucessful accessibility framework with DCOP.

Now, next onto breaking down the various points.


NB, for those reading on AT-SPI lists, the rest of the technical
discussion will only be on the dbus mailing list to not spam everyone..

Rob Taylor, Codethink Ltd. -

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