[AUCTeX-devel] Re: [AUCTeX] Inverse Search with Evince & DBUS

[Michael Albinus]

Tassilo Horn <address@hidden> writes:

> Hi Ralf,

Hi,

>> Ideally the function should only be called if a Dbus-aware viewer is
>> selected and be fed with the parameters which are specific to that
>> viewer.
>
> I guess, all the options are specific to Evince.

You could ask for the D-Bus existence of such a viewer. For Evince, I
would try

(member
 "org.gnome.evince.Daemon"
 (dbus-call-method
  :session dbus-service-dbus
  dbus-path-dbus dbus-interface-dbus "ListActivatableNames"))

(`dbus-list-activatable-names' should provide this information; I've
just seen it does it for the system bus only. I'll fix it in Emacs 24.1)

>> Do you know if listening to Dbus signals is resource intensive or has
>> any security implications?  If that's the case we might at least have
>> to provide a way to switch it off.
>
> I don't know.  At least I cannot notice any performance issues on my
> system.  However, I don't know if it can get resource intensive to
> dispatch between many messages and signals to pick the one(s) emacs has
> registered for.  You might want to use `dbus-monitor' to see what goes
> over the bus.

If Emacs is built with D-Bus support, the mainloop looks for incoming
D-Bus events. No further burden, whether you register something, or not.

When Emacs registers for a signal, exactly *this* signal is sent from
the D-Bus to Emacs, and no other one. Handling of such a signal might
last some tenths of a second, but it does not happen often.

> WRT security, what goes over the session bus is only the basename of the
> TeX document and a line number (and a column number that is always -1).

Indeed.

> Bye,
> Tassilo

Best regards, Michael.