Bug 143542 – PangoFT2Fontmap leak

2008-08-22  Behdad Esfahbod  <behdad@gnome.org>

        Bug 143542 – PangoFT2Fontmap leak

        * pango/fonts.c:
        * pango/pangoatsui.c (pango_atsui_font_finalize),
        (_pango_atsui_font_set_font_map):
        * pango/pangocairo-font.c (_pango_cairo_font_get_metrics),
        (_pango_cairo_font_private_get_hex_box_info):
        * pango/pangocairo-win32font.c (_pango_cairo_win32_font_new):
        * pango/pangofc-font.c (pango_fc_font_get_metrics):
        * pango/pangofc-fontmap.c (pango_fc_font_map_add),
        (_pango_fc_font_map_remove), (cleanup_font):
        * pango/pangowin32-fontmap.c (pango_win32_font_neww),
        (pango_win32_font_map_real_find_font):
        * pango/pangowin32.c (pango_win32_font_finalize):
        * pango/pangox-fontmap.c (pango_x_font_map_load_font):
        * pango/pangox.c (pango_x_font_new), (pango_x_font_finalize):
        Make the reference the font->fontmap reference weak.

        The code for setting the reference must look like this:

          g_assert (font->fontmap == NULL);
          font->fontmap = (PangoFontMap *) fontmap;
          g_object_add_weak_pointer (G_OBJECT (font->fontmap), (gpointer *) (gpointer) &font->fontmap);

        And releasing it like:

          g_assert (font->fontmap != NULL);
          g_object_remove_weak_pointer (G_OBJECT (font->fontmap), (gpointer *) (gpointer) &font->fontmap);
          font->fontmap = NULL;

        I have converted all fontmaps.  The win32 and atsui ones can
        use some simple testing.

        The PangoFc fonts actually don't need the weakref as the fontmap
        already provides a similar link by itself.

svn path=/trunk/; revision=2704

1 files changed, 9 insertions, 1 deletions

diff --git a/pango/fonts.c b/pango/fonts.c
index efb989bb..2f997035 100644
--- a/pango/fonts.c
+++ b/pango/fonts.c
@@ -1414,10 +1414,18 @@ pango_font_get_metrics (PangoFont        *font,
 
 /**
  * pango_font_get_font_map:
- * @font: a #PangoFont
+ * @font: a #PangoFont, or %NULL
  *
  * Gets the font map for which the font was created.
  *
+ * Note that the font maintains a <firstterm>weak</firstterm> reference
+ * to the font map, so if all references to font map are dropped, the font
+ * map will be finalized even if there are fonts created with the font
+ * map that are still alive.  In that case this function will return %NULL.
+ * It is the responsibility of the user to ensure that the font map is kept
+ * alive.  In most uses this is not an issue as a #PangoContext holds
+ * a reference to the font map.
+ *
  * Return value: the #PangoFontMap for the font, or %NULL if @font is %NULL.
  *
  * Since: 1.10