[LAD] Session Handlers and 'level 1' support

[Chris Cannam]

On Fri, Jan 8, 2010 at 11:00 AM, Nedko Arnaudov <nedko at arnaudov.name> wrote:
> Chris Cannam <cannam at all-day-breakfast.com> writes:
>> What I mean is: if the user starts an application that has no
>> knowledge of LADI at all, and they check the level 1 box in ladish, is
>> that application then guaranteed to crash on session save and lose
>> their data because of an unhandled signal?
>
> If user checks level 1 in ladish when starting the app, then ladish will
> send SIGUSR1 to the app. If the app actually does not support level 1,
> signal will be sent and chances are that default signal handler will be
> executed. The default signal handler is to terminate the app.

That sounds rather hazardous to me.  To lose all of one's data instead
of saving it, after a potentially long session's work, because of a
check box incorrectly checked when starting the session, surely
wouldn't please many users?

> Applications cannot register themself yet.

I think I must have misunderstood the use of D-BUS here, then.  I had
thought that LADI was a D-BUS service which the application connected
to, so that LADI would know whether an application was running in a
"LADI-aware" state or not.


Chris