Do not crash if the (win32 typically) shaper fails. Bug #304702:

2006-01-29  Behdad Esfahbod  <behdad@gnome.org>

        Do not crash if the (win32 typically) shaper fails. Bug #304702:

        * pango/pango-engine.c (_pango_engine_shape_shape): Set num_glyphs to
        zero if failing.

        * pango/pango-shape.c (pango_shape): Instead of crashing if the shaper
        failed to produce any glyphs, print out a warning message containing
        the name of the font, and mark the font such that we don't keep
        printing warning for the same font.

4 files changed, 54 insertions, 6 deletions

diff --git a/ChangeLog b/ChangeLog
index 0e5a0807..3a0468ac 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,15 @@
+2006-01-29  Behdad Esfahbod  <behdad@gnome.org>
+
+	Do not crash if the (win32 typically) shaper fails. Bug #304702:
+
+	* pango/pango-engine.c (_pango_engine_shape_shape): Set num_glyphs to
+	zero if failing.
+
+	* pango/pango-shape.c (pango_shape): Instead of crashing if the shaper
+	failed to produce any glyphs, print out a warning message containing
+	the name of the font, and mark the font such that we don't keep
+	printing warning for the same font.
+
 2006-01-28  Behdad Esfahbod  <behdad@gnome.org>
 
 	* .cvsusers: Removed.
diff --git a/pango/pango-coverage.c b/pango/pango-coverage.c
index 500dee24..2a68ea05 100644
--- a/pango/pango-coverage.c
+++ b/pango/pango-coverage.c
@@ -449,7 +449,7 @@ pango_coverage_from_bytes (guchar *bytes,
 {
   PangoCoverage *coverage = g_new0 (PangoCoverage, 1);
   guchar *ptr = bytes;
- int i;
+  int i;
 
   coverage->ref_count = 1;
   
diff --git a/pango/pango-engine.c b/pango/pango-engine.c
index 7517679d..4179119f 100644
--- a/pango/pango-engine.c
+++ b/pango/pango-engine.c
@@ -66,6 +66,8 @@ _pango_engine_shape_shape (PangoEngineShape *engine,
 			   PangoAnalysis    *analysis,
 			   PangoGlyphString *glyphs)
 {
+  glyphs->num_glyphs = 0;
+
   g_return_if_fail (PANGO_IS_ENGINE_SHAPE (engine));
   g_return_if_fail (PANGO_IS_FONT (font));
   g_return_if_fail (text != NULL);
diff --git a/pango/shape.c b/pango/shape.c
index 9a8b42e5..24902a47 100644
--- a/pango/shape.c
+++ b/pango/shape.c
@@ -43,11 +43,47 @@ pango_shape (const gchar      *text,
 {
   int i;
   int last_cluster = -1;
-  
+
   if (analysis->shape_engine)
-    _pango_engine_shape_shape (analysis->shape_engine, analysis->font,
-			       text, length, analysis, glyphs);
+    {
+      _pango_engine_shape_shape (analysis->shape_engine, analysis->font,
+				 text, length, analysis, glyphs);
+
+      if (G_UNLIKELY (glyphs->num_glyphs == 0 && analysis->font))
+        {
+	  /* 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.
+	   */
+	  static GQuark warned_quark = 0;
+
+	  if (!warned_quark)
+	    warned_quark = g_quark_from_static_string ("pango-shaper-warned");
+	  
+	  if (!g_object_get_qdata (G_OBJECT (analysis->font), warned_quark))
+	    {
+	      PangoFontDescription *desc;
+	      char *s;
+
+	      desc = pango_font_describe (analysis->font);
+	      s = pango_font_description_to_string (desc);
+	      pango_font_description_free (desc);
+
+	      g_warning ("shape engine failure, expect ugly output. the offending font is `%s'", s);
+
+	      g_free (s);
+
+	      g_object_set_qdata_full (G_OBJECT (analysis->font), warned_quark,
+				       GINT_TO_POINTER (1), NULL);
+	    }
+	}
+    }
   else
+    glyphs->num_glyphs = 0;
+
+  if (!glyphs->num_glyphs)
     {
       pango_glyph_string_set_size (glyphs, 1);
 
@@ -72,6 +108,4 @@ pango_shape (const gchar      *text,
       else
 	glyphs->glyphs[i].attr.is_cluster_start = FALSE;
     }
-	    
-  g_assert (glyphs->num_glyphs > 0);
 }