* font.c (valid_font_driver) [ENABLE_CHECKING]: New function

intended to find bogus pointers in font objects (Bug#16140).
* font.h (valid_font_driver) [ENABLE_CHECKING]: Add prototype.
* alloc.c (cleanup_vector): Use valid_font_driver in eassert.
(compact_font_cache_entry, compact_font_caches) [!HAVE_NTGUI]:
Disable for MS-Windows due to Bug#15876; apparently this
requires more or less substantial changes in fontset code.
* xfont.c (xfont_close):
* xftfont.c (xftfont_close): Call x_display_info_for_display
to check whether 'Display *' is valid (Bug#16093 and probably
Bug#16069).

1 files changed, 13 insertions, 2 deletions

diff --git a/src/alloc.c b/src/alloc.c
index aeda42637cd..447b465a076 100644
--- a/src/alloc.c
+++ b/src/alloc.c
@@ -2877,7 +2877,11 @@ cleanup_vector (struct Lisp_Vector *vector)
   if (PSEUDOVECTOR_TYPEP (&vector->header, PVEC_FONT)
       && ((vector->header.size & PSEUDOVECTOR_SIZE_MASK)
           == FONT_OBJECT_MAX))
-    ((struct font *) vector)->driver->close ((struct font *) vector);
+    {
+      /* Attempt to catch subtle bugs like Bug#16140.  */
+      eassert (valid_font_driver (((struct font *) vector)->driver));
+      ((struct font *) vector)->driver->close ((struct font *) vector);
+    }
 }
 
 /* Reclaim space used by unmarked vectors.  */
@@ -5299,6 +5303,10 @@ total_bytes_of_live_objects (void)
 
 #ifdef HAVE_WINDOW_SYSTEM
 
+/* This code has a few issues on MS-Windows, see Bug#15876 and Bug#16140.  */
+
+#if !defined (HAVE_NTGUI)
+
 /* Remove unmarked font-spec and font-entity objects from ENTRY, which is
    (DRIVER-TYPE NUM-FRAMES FONT-CACHE-DATA ...), and return changed entry.  */
 
@@ -5337,6 +5345,8 @@ compact_font_cache_entry (Lisp_Object entry)
   return entry;
 }
 
+#endif /* not HAVE_NTGUI */
+
 /* Compact font caches on all terminals and mark
    everything which is still here after compaction.  */
 
@@ -5348,7 +5358,7 @@ compact_font_caches (void)
   for (t = terminal_list; t; t = t->next_terminal)
     {
       Lisp_Object cache = TERMINAL_FONT_CACHE (t);
-
+#if !defined (HAVE_NTGUI)
       if (CONSP (cache))
         {
           Lisp_Object entry;
@@ -5356,6 +5366,7 @@ compact_font_caches (void)
           for (entry = XCDR (cache); CONSP (entry); entry = XCDR (entry))
             XSETCAR (entry, compact_font_cache_entry (XCAR (entry)));
         }
+#endif /* not HAVE_NTGUI */
       mark_object (cache);
     }
 }