check_single_font(): use quotation mark when msGetGlyphIndex() fails …

…to retrieve the glyph

msautotest/renderers/font-fail.map

@@ -1,5 +1,6 @@
 # RUN_PARMS: font-fail-key.txt [MAPSERV] QUERY_STRING="map=[MAPFILE]&mode=map&layer=l1" > [RESULT_DEVERSION]
 # RUN_PARMS: font-fail-file.txt [MAPSERV] QUERY_STRING="map=[MAPFILE]&mode=map&layer=l2" > [RESULT_DEVERSION]
+# RUN_PARMS: font-fail-missing-glyph.png [SHP2IMG] -m [MAPFILE] -l missing_glyph -i png -o [RESULT]
 
 MAP
 
@@ -41,4 +42,21 @@ LAYER
  FEATURE POINTS 50 50 END END
 END
 
+LAYER
+    NAME "missing_glyph"
+    STATUS ON
+    TYPE POLYGON
+    FEATURE
+      POINTS 0 0 400 0 400 300 0 300 0 0 END
+    END
+    CLASS
+        LABEL
+            TEXT 'this is a test: это проверка'
+            TYPE truetype
+            SIZE 8
+            FONT "default"
+        END
+    END
+END
+
 END

textlayout.c

@@ -214,7 +214,7 @@ static hb_position_t _ms_get_glyph_v_advance_func (hb_font_t *font, void *font_d
 }
 #endif
 
-int WARN_UNUSED check_single_font(fontSetObj *fontset, char *fontkey, text_run *run, TextInfo *glyphs, int ignore_missing) {
+static int check_single_font(fontSetObj *fontset, char *fontkey, text_run *run, TextInfo *glyphs, int ignore_missing) {
   int i;
   face_element *fcache = NULL;
   if(fontset && fontkey) {
@@ -228,16 +228,23 @@ int WARN_UNUSED check_single_font(fontSetObj *fontset, char *fontkey, text_run *
   run->face = fcache;
   if(UNLIKELY(!fcache)) return MS_FAILURE;
   for(i=0; i<run->length; i++) {
-    int codepoint = msGetGlyphIndex(fcache, glyphs->unicodes[run->offset+i]);
+    unsigned int codepoint = msGetGlyphIndex(fcache, glyphs->unicodes[run->offset+i]);
     if(codepoint || ignore_missing)
+    {
+      if( codepoint == 0 )
+      {
+          msDebug("Unable to find glyph for codepoint %u. Using ? as fallback.\n", glyphs->unicodes[run->offset+i]);
+          codepoint = msGetGlyphIndex(fcache, '?');
+      }
       glyphs->codepoints[run->offset+i] = codepoint;
+    }
     else
       return MS_FAILURE;
   }
   return MS_SUCCESS;
 }
 
-int WARN_UNUSED get_face_for_run(fontSetObj *fontset, char *fontlist, text_run *run, TextInfo *glyphs) {
+static int get_face_for_run(fontSetObj *fontset, char *fontlist, text_run *run, TextInfo *glyphs) {
   char *startfont, *endfont;
   int ok;
 #if defined(USE_HARFBUZZ) && defined(USE_FRIBIDI)