gio async usage from gtk+ ...

[Michael Meeks <michael meeks novell com>]

Hi guys,

	I was just digging into a libreoffice assertion failure when using the
gtk+ file selector:

Gtk:ERROR:gtkfilesystemmodel.c:746:gtk_file_system_model_sort: assertion
failed: (r == n_visible_rows)

	which looked to me, like it could well be a thread related issue; in
particular since I'm browsing a 'busy' directory (ie. /tmp/ that my
compilation is thrashing small files into and out of, no doubt creating
thrash on the model too[1]).

	I had a dig around in gtk/gtkfilesystemmodel.c on gtk-2-24 (I assume
that is the last stable branch before 3.0), to see how threading is
supposed to work; my trace is something like:

#2  0xb7c8c140 in abort () from /lib/libc.so.6
#3  0xb401de52 in g_assertion_message (domain=0xb454df3b "Gtk", file=0xb45647f6 "gtkfilesystemmodel.c", line=746, func=0xb4564a84 "gtk_file_system_model_sort", 
    message=<value optimized out>) at gtestutils.c:1358
#4  0xb401e47f in g_assertion_message_expr (domain=0xb454df3b "Gtk", file=0xb45647f6 "gtkfilesystemmodel.c", line=746, func=0xb4564a84 "gtk_file_system_model_sort", expr=
    0xb4564870 "r == n_visible_rows") at gtestutils.c:1369
#5  0xb4342d8f in gtk_file_system_model_sort (model=<value optimized out>) at gtkfilesystemmodel.c:727
#6  0xb4344b8e in _gtk_file_system_model_update_file (model=0x9981f48 [GtkFileSystemModel], file=0xae6918b0, info=0x90538b0, requires_resort=1) at gtkfilesystemmodel.c:1782
#7  0xb4344cb0 in gtk_file_system_model_query_done (object=0xae6918b0 [GLocalFile], res=0x9168c38, data=0x9981f48) at gtkfilesystemmodel.c:1153
#8  0xb3c15969 in g_simple_async_result_complete (simple=0x9168c38 [GSimpleAsyncResult]) at gsimpleasyncresult.c:747
#9  0xb3c15a03 in complete_in_idle_cb_for_thread (_data=0x99c5af0) at gsimpleasyncresult.c:812
#10 0xb3ff1e40 in g_idle_dispatch (source=0x9169518, callback=0xb3c159d0 <complete_in_idle_cb_for_thread>, user_data=0x99c5af0) at gmain.c:4536
#11 0xb3ff64f9 in g_main_dispatch (context=0x8086d60) at gmain.c:2440
#12 g_main_context_dispatch (context=0x8086d60) at gmain.c:3013
#13 0xb3ff6d00 in g_main_context_iterate (context=0x8086d60, block=1, dispatch=1, self=0x80527a8) at gmain.c:3091
#14 0xb3ff73df in g_main_loop_run (loop=0x998a130) at gmain.c:3299
#15 0xb43074af in IA__gtk_dialog_run (dialog=0x96f1848 [GtkFileChooserDialog]) at gtkdialog.c:1094
#16 0x8557e8d4 in ?? () from /usr/lib/libreoffice/program/../basis-link/program/fps_gnome.uno.so
etc.

	And I wonder where the GDK_THREADS_ENTER / GDK_THREADS_LEAVE that we
need when entering from an idle handler is.

	Presumably this is necessary for every '_async' callback that occurs
[ and lets hope they are 100% called from the idle handler, and not
sometimes for error conditions in-line ;-]. 

	And I was wondering: que ? there are ~24 of these '_async (' matches in
gtk+, and of the few I spot-checked, none take the lock; feature or
bug ?

	Thanks,

		Michael.

[1] - the file change handling FWIW is horribly inefficient, and once
you have saved-as a /tmp file, life is really bad for your app (it goes
away for long periods) for ever after if you start doing things actively
in /tmp; at least for me of course ;-)
-- 
 michael meeks novell com  <><, Pseudo Engineer, itinerant idiot