Bug 466755 – pango hangul is crashing in gnome-about because it is

2007-08-14  Behdad Esfahbod  <behdad@gnome.org>

        Bug 466755 – pango hangul is crashing in gnome-about because it is
        failing to retrieve a font.

        * pango/pangofc-font.c (pango_fc_font_real_get_glyph),
        (pango_fc_font_kern_glyphs), (pango_fc_font_get_raw_extents):
        Protect against NULL face.

        * pango/shape.c (pango_shape): Improve error message by writing
        out shaping engine type name and the text too.


svn path=/trunk/; revision=2396

3 files changed, 62 insertions, 19 deletions

diff --git a/ChangeLog b/ChangeLog
index 36da2a33..45af68b4 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,17 @@
 2007-08-14  Behdad Esfahbod  <behdad@gnome.org>
 
+	Bug 466755 – pango hangul is crashing in gnome-about because it is
+	failing to retrieve a font.
+
+	* pango/pangofc-font.c (pango_fc_font_real_get_glyph),
+	(pango_fc_font_kern_glyphs), (pango_fc_font_get_raw_extents):
+	Protect against NULL face.
+
+	* pango/shape.c (pango_shape): Improve error message by writing
+	out shaping engine type name and the text too.
+
+2007-08-14  Behdad Esfahbod  <behdad@gnome.org>
+
 	* pango/pango-script.h (pango_script_for_unichar): Mark G_GNUC_CONST.
 
 2007-08-09  Behdad Esfahbod  <behdad@gnome.org>
diff --git a/pango/pangofc-font.c b/pango/pangofc-font.c
index dec1f680..f48cffb7 100644
--- a/pango/pangofc-font.c
+++ b/pango/pangofc-font.c
@@ -560,14 +560,19 @@ pango_fc_font_real_get_glyph (PangoFcFont *font,
   if (entry->ch != wc)
     {
       face = PANGO_FC_FONT_LOCK_FACE (font);
-      index = FcFreeTypeCharIndex (face, wc);
-      if (index > (FT_UInt)face->num_glyphs)
-	index = 0;
+      if (G_LIKELY (face))
+        {
+	  index = FcFreeTypeCharIndex (face, wc);
+	  if (index > (FT_UInt)face->num_glyphs)
+	    index = 0;
+
+	  PANGO_FC_FONT_UNLOCK_FACE (font);
+	}
+      else
+        index = 0;
 
       entry->ch = wc;
       entry->glyph = index;
-
-      PANGO_FC_FONT_UNLOCK_FACE (font);
     }
 
   return entry->glyph;
@@ -729,7 +734,7 @@ pango_fc_font_kern_glyphs (PangoFcFont      *font,
   g_return_if_fail (glyphs != NULL);
 
   face = PANGO_FC_FONT_LOCK_FACE (font);
-  if (!face)
+  if (G_UNLIKELY (!face))
     return;
 
   if (!FT_HAS_KERNING (face))
@@ -871,6 +876,12 @@ pango_fc_font_get_raw_extents (PangoFcFont    *fcfont,
   g_return_if_fail (PANGO_IS_FC_FONT (fcfont));
 
   face = PANGO_FC_FONT_LOCK_FACE (fcfont);
+  if (G_UNLIKELY (!face))
+    {
+      /* Get generic unknown-glyph extents. */
+      pango_font_get_glyph_extents (NULL, glyph, ink_rect, logical_rect);
+      return;
+    }
 
   if (glyph == PANGO_GLYPH_EMPTY)
     gm = NULL;
diff --git a/pango/shape.c b/pango/shape.c
index 96bcb672..1fd2d814 100644
--- a/pango/shape.c
+++ b/pango/shape.c
@@ -25,6 +25,8 @@
 #include "pango-glyph.h"
 #include "pango-engine-private.h"
 
+#include <string.h>
+
 /**
  * pango_shape:
  * @text:      the text to process
@@ -56,29 +58,47 @@ pango_shape (const gchar      *text,
       if (G_UNLIKELY (glyphs->num_glyphs == 0))
 	{
 	  /* If a font has been correctly chosen, but no glyphs are output,
-	   * there's probably something wrong with the shaper.  Trying to be
-	   * informative, we print out the font description, but to not
-	   * flood the terminal with zillions of the message, we set a flag
-	   * on the font to only err once per font.
+	   * there's probably something wrong with the shaper, or the font.
+	   *
+	   * Trying to be informative, we print out the font description,
+	   * shaper name, and the text, but to not flood the terminal with
+	   * zillions of the message, we set a flag to only err once per
+	   * font/engine pair.
+	   *
+	   * To do the flag fast, we use the engine qname to qflag the font,
+	   * but also the font description to flag the engine.  This is
+	   * supposed to be fast to check, but also avoid writing out
+	   * duplicate warnings when a new PangoFont is created.
 	   */
-	  static GQuark warned_quark = 0;
-
-	  if (!warned_quark)
-	    warned_quark = g_quark_from_static_string ("pango-shaper-warned");
+	  GType engine_type = G_OBJECT_TYPE (analysis->shape_engine);
+	  GQuark warned_quark = g_type_qname (engine_type);
 
 	  if (!g_object_get_qdata (G_OBJECT (analysis->font), warned_quark))
 	    {
 	      PangoFontDescription *desc;
-	      char *s;
+	      char *font_name;
+	      const char *engine_name;
 
 	      desc = pango_font_describe (analysis->font);
-	      s = pango_font_description_to_string (desc);
+	      font_name = pango_font_description_to_string (desc);
 	      pango_font_description_free (desc);
 
-	      /* TODO: Write out the beginning excerpt of text here? */
-	      g_warning ("shape engine failure, expect ugly output. the offending font is '%s'", s);
+	      if (!g_object_get_data (G_OBJECT (analysis->shape_engine), font_name))
+	        {
+		  engine_name = g_type_name (engine_type);
+		  if (!engine_name)
+		    engine_name = "(unknown)";
+
+		  g_warning ("shaping failure, expect ugly output. shape-engine='%s', font='%s', text='%.*s'",
+			     engine_name,
+			     font_name,
+			     length == -1 ? (gint) strlen (text) : length, text);
+
+		  g_object_set_data_full (G_OBJECT (analysis->shape_engine), font_name,
+					  GINT_TO_POINTER (1), NULL);
+	        }
 
-	      g_free (s);
+	      g_free (font_name);
 
 	      g_object_set_qdata_full (G_OBJECT (analysis->font), warned_quark,
 				       GINT_TO_POINTER (1), NULL);