Bug 314239 – pangocairo crashes when font cannot be read

2006-02-21  Behdad Esfahbod  <behdad@gnome.org>

        Bug 314239 – pangocairo crashes when font cannot be read

        * pango/pangocairo-fcfont.c, pango/pangocairo-font.c: Hack up to not
        crash if we cannot create cairo_scaled_font_t for PangoFont (font is
        not readable, removed, etc.)

4 files changed, 46 insertions, 6 deletions

diff --git a/ChangeLog b/ChangeLog
index 8b34e61b..5cfc27fb 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,13 @@
 2006-02-21  Behdad Esfahbod  <behdad@gnome.org>
 
+	Bug 314239 – pangocairo crashes when font cannot be read
+
+	* pango/pangocairo-fcfont.c, pango/pangocairo-font.c: Hack up to not
+	crash if we cannot create cairo_scaled_font_t for PangoFont (font is
+	not readable, removed, etc.)
+
+2006-02-21  Behdad Esfahbod  <behdad@gnome.org>
+
 	Bug 331723 – shapers should not crash on failures
 
 	* modules/*/*-fc.c: Return instead of g_return_if_fail when
diff --git a/pango/pangocairo-fcfont.c b/pango/pangocairo-fcfont.c
index e4ff8a31..086368ff 100644
--- a/pango/pangocairo-fcfont.c
+++ b/pango/pangocairo-fcfont.c
@@ -133,11 +133,11 @@ pango_cairo_fc_font_get_font_face (PangoCairoFont *font)
     {
       cffont->font_face = cairo_ft_font_face_create_for_pattern (fcfont->font_pattern);
       
-      /* Failure of the above should only occur for out of memory,
-       * we can't proceed at that point
+      /* Unable to create FT2 cairo scaled font.
+       * This means out of memory or a cairo/fontconfig/FreeType bug,
        */
       if (!cffont->font_face)
-	g_error ("Unable to create FT2 cairo font face.\nThis means out of memory or a cairo/fontconfig/FreeType bug");
+        return NULL;
     }
   
   return cffont->font_face;
@@ -154,16 +154,20 @@ pango_cairo_fc_font_get_scaled_font (PangoCairoFont *font)
 
       font_face = pango_cairo_fc_font_get_font_face (font);
 
+      if (!font_face)
+        return NULL;
+
       cffont->scaled_font = cairo_scaled_font_create (font_face,
 						      &cffont->font_matrix,
 						      &cffont->ctm,
 						      cffont->options);
 
-      /* Failure of the above should only occur for out of memory,
-       * we can't proceed at that point
+      /* Unable to create FT2 cairo scaled font.
+       * This means out of memory or a cairo/fontconfig/FreeType bug,
+       * or a missing font...
        */
       if (!cffont->scaled_font)
-	g_error ("Unable to create FT2 cairo scaled font.\nThis means out of memory or a cairo/fontconfig/FreeType bug");
+        return NULL;
     }
   
   return cffont->scaled_font;
@@ -292,6 +296,8 @@ pango_cairo_fc_font_lock_face (PangoFcFont *font)
 {
   PangoCairoFont *cfont = (PangoCairoFont *)font;
   cairo_scaled_font_t *scaled_font = pango_cairo_fc_font_get_scaled_font (cfont);
+  if (G_UNLIKELY (!scaled_font))
+    return NULL;
   
   return cairo_ft_scaled_font_lock_face (scaled_font);
 }
@@ -301,6 +307,8 @@ pango_cairo_fc_font_unlock_face (PangoFcFont *font)
 {
   PangoCairoFont *cfont = (PangoCairoFont *)font;
   cairo_scaled_font_t *scaled_font = pango_cairo_fc_font_get_scaled_font (cfont);
+  if (G_UNLIKELY (!scaled_font))
+    return NULL;
   
   cairo_ft_scaled_font_unlock_face (scaled_font);
 }
@@ -354,6 +362,7 @@ pango_cairo_fc_font_glyph_extents_cache_init (PangoCairoFcFont *cffont)
   PangoCairoFont *cfont = (PangoCairoFont *)cffont;
   cairo_scaled_font_t *scaled_font = pango_cairo_fc_font_get_scaled_font (cfont);
   cairo_font_extents_t font_extents;
+
   cairo_scaled_font_extents (scaled_font, &font_extents);
 
   cffont->font_extents.x = 0;
@@ -435,6 +444,13 @@ pango_cairo_fc_font_get_glyph_extents (PangoFont      *font,
   PangoCairoFcFont *cffont = (PangoCairoFcFont *)font;
   GlyphExtentsCacheEntry *entry;
 
+  if (!pango_cairo_fc_font_get_scaled_font ((PangoCairoFont *)cffont))
+    {
+      /* Get generic unknown-glyph extents. */
+      pango_font_get_glyph_extents (NULL, glyph, ink_rect, logical_rect);
+      return;
+    }
+
   /* We need to initialize the cache here, since we use cffont->font_extents
    */
   if (cffont->glyph_extents_cache == NULL)
diff --git a/pango/pangocairo-font.c b/pango/pangocairo-font.c
index 1e8112c4..cba260fd 100644
--- a/pango/pangocairo-font.c
+++ b/pango/pangocairo-font.c
@@ -146,6 +146,11 @@ _pango_cairo_font_get_hex_box_info (PangoCairoFont *cfont)
     return hbi;
 
   scaled_font = _pango_cairo_font_get_scaled_font (cfont);  
+  if (!scaled_font)
+    {
+      g_object_set_data_full (G_OBJECT (cfont), "hex_box_info", NULL, NULL); 
+      return NULL;
+    }
 
 #ifdef HAVE_CAIRO_SCALED_FONT_GETTERS
   /* prepare for some hinting */
diff --git a/pango/pangofc-font.c b/pango/pangofc-font.c
index 5bea0e81..d6e2d8fd 100644
--- a/pango/pangofc-font.c
+++ b/pango/pangofc-font.c
@@ -291,6 +291,17 @@ get_face_metrics (PangoFcFont      *fcfont,
   TT_OS2 *os2;
   gboolean have_transform = FALSE;
 
+  if (!face)
+    {
+      metrics->descent = 0;
+      metrics->ascent = PANGO_SCALE * PANGO_UNKNOWN_GLYPH_HEIGHT;
+      metrics->underline_thickness = PANGO_SCALE;
+      metrics->underline_position = - PANGO_SCALE;
+      metrics->strikethrough_thickness = PANGO_SCALE;
+      metrics->strikethrough_position = PANGO_SCALE * (PANGO_UNKNOWN_GLYPH_HEIGHT/2);
+      return;
+    }
+
   if  (FcPatternGetMatrix (fcfont->font_pattern,
 			   FC_MATRIX, 0, &fc_matrix) == FcResultMatch)
     {