Re: Memleak in canvas_paint, update

On Sat, 2004-12-04 at 08:33 -0800, Al Hooton wrote:

> I've been able to track it down to gtk_plot_canvas_paint().  I will keep
> working to get lower in the stack...

	Using the gutted testgtkplotcanvas.c I sent earlier, I have spent this
morning digging down the call stack to see what I can find.  I have
bottomed out at gtk_plot_gdk_draw_string.  The memprof tool tells me
this routine is where about 95% of the leaks I'm seeing are being
caused, although it could be happening in libraries further down, but I
don't have symbols built in those (yet).  Here's the call stack, with
line numbers, starting at the canvas_paint call in testgtkplotcanvas:

gtk_plot_canvas_paint:906
gtk_plot_canvas_child_draw:1980
gtk_plot_canvas_plot_draw:162
gtk_plot_paint:1917
gtk_plot_real_paint:2040
gtk_plot_draw_labels:2630
gtk_plot_draw_text:3011
gtk_plot_pc_draw_string:264
gtk_plot_gdk_draw_string:626

	That's as far down as it goes.  The gdk_draw_string routine does it's
thing, and the call stack unwinds all the way back up.

	I have been walking through gdk_draw_string, to see if I can find
anything obvious.  Only two things have jumped out at me, and neither of
them takes care of the leak:

- The variable "colormap" is initialized with gdk_colormap_get_system(),
but then is not used for anything.

- It appears that if (psfont->i18n_latinfamily) is true, then the
"latin_font" variable is assigned from gtk_psfont_get_font_description,
but it is never subsequently freed with a call to
"pango_font_description_free), although with my lack of pango knowledge,
I may not be understanding this correctly.

	When adding test code to take care of the above items, the leaks still
occur.

	My problem now is that this is the first time I've gotten this close to
the pango API (something I had not planned on needing to do), and I
don't at all claim to understand the memory management
conventions/guidelines therein.

	My next step will be to fully instrument GDK and pango with symbols and
profiling hooks (as I have done with gtkextra and GTK+), and see if I
can get farther down the rabbit hole.  Since I've not been inside any of
the pango stuff before. I'm not sure how much help I'll be able to
provide in driving further debugging, but I'll keep going until the
White Rabbit warns me against going further...   8^)=

	All thoughts, suggestions, warnings, and weapons to use on my journey
are greatly appreciated....     8^)=

-Al




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