Match font registry after font is opened

* src/fontset.c (fontset_find_font): Work around TrueType
performance problem.

diff --git a/src/fontset.c b/src/fontset.c
index f196dee8259b25241c93188f46f77d7f609a9d86..8182d639299daea9dd0b3ad83cbb655fbae4d8fc 100644 (file)
--- a/src/fontset.c
+++ b/src/fontset.c
@@ -667,8 +667,29 @@ fontset_find_font (Lisp_Object fontset, int c, struct face *face,
            }
          font_object = font_open_for_lface (f, font_entity, face->lface,
                                             FONT_DEF_SPEC (font_def));
+
+         /* If the font registry is not the same as explicitly
+            specified in the font spec, do not cache the font.
+            TrueType fonts have contrived character map selection
+            semantics which makes determining the repertory at font
+            spec matching time unduly expensive.  */
+
+         {
+           Lisp_Object spec;
+
+           spec = FONT_DEF_SPEC (font_def);
+
+           if (!NILP (font_object)
+               && !NILP (AREF (spec, FONT_REGISTRY_INDEX))
+               && !NILP (AREF (font_object, FONT_REGISTRY_INDEX))
+               && !EQ (AREF (spec, FONT_REGISTRY_INDEX),
+                       AREF (font_object, FONT_REGISTRY_INDEX)))
+             goto strangeness;
+         }
+
          if (NILP (font_object))
            {
+           strangeness:
              /* Something strange happened, perhaps because of a
                 Font-backend problem.  To avoid crashing, record
                 that this spec is unusable.  It may be better to find