Re: LibUnique as blessed dependency

[Havoc Pennington <hp redhat com>]

Hi,

Elijah Newren wrote:
> I think you're still mostly ignoring a big part of the puzzle.  IMO,
> D-Bus (as it exists today) is not a complete solution for this
> problem.  I do not recall yet seeing an application author of a
> single-instance application (whether they used D-Bus, X, bonobo,
> bacon, or something else) try to handle startup-notification on their
> own and get it right.  Maybe there was such a case and I missed it or
> forgot it, but I've seen dozens of apps get it wrong in various ways
> and plenty of others just not even attempt to get things right.

I don't mean to ignore this - I agree it's needed and "the hard part"

We did basically have this thread before I guess, I just dug out of 
Google my post saying the same thing I said this time, more or less:
http://mail.gnome.org/archives/desktop-devel-list/2006-September/msg00470.html

It would be nice IMO to go ahead and create a wiki page documenting the 
D-Bus interface - the Launch() thing or equivalent, and if it has a dict 
of properties, what the major properties are (in particular the DISPLAY, 
uris-to-open, and startup-notification-related properties).

I think it's important for libunique to 'look right' at the raw dbus 
protocol level as I talked about in that September post. I'm not quite 
sure where to find the latest libunique code? Google is not turning it up.

> The multiple backends, IMO, are just historical cruft from libgunique.

Thanks, this is good news. Avoiding extra complexity is always a plus!

To have a discussion topic at GUADEC I started poking at a "dbus 
convenience library" called "gbus" that is a different angle from the 
various current language bindings - rather than focusing on the 
Object<->IPC mapping and wrapping dbus/dbus.h, it just includes 
dbus/dbus.h wholesale and adds convenience API for things like:
 - tracking bus name owners as they come and go
 - tracking clients using an interface you provide, so you can exit when
   none are left
 - handling of bus names you own, providing the "be sure there is one of
   me" part of single instance but not the "startup notification etc."
   part
 - tracking the bus itself as it comes and goes, in case you want to
   get ambitious and handle system bus restart
This is based on hippo-dbus-helper.c which is used in the mugshot client 
and local-export-daemon. I'll post code sometime during GUADEC probably, 
I have to finish packing at the moment.

Anyway, something like this (aside from being needed so dbus can be used 
from C without writing a ton of code), would make the IPC part of single 
instance super easy.

The part that would remain, of course, is the gtk stuff - parsing the 
environment and command line options from the binary that was launched 
into some serializable form, and then unpacking that and doing the right 
magic to open on the right screen with the right startup notification in 
the binary that owns the single instance.

Havoc