Fix a memory leak in GC of font cache

* src/alloc.c (compact_font_cache_entry): Don't GC unmarked font
entities if some of the fonts it references are marked.  This
plugs a memory leak.  (Bug#21556)

diff --git a/src/alloc.c b/src/alloc.c
index 60751bcfe2bc768c0b8036c8f4b6b7d7f0705fdc..81d644a16ad28c8ebcd8052d826e4e3993260dea 100644 (file)
--- a/src/alloc.c
+++ b/src/alloc.c
@@ -5328,11 +5328,35 @@ compact_font_cache_entry (Lisp_Object entry)
             are not marked too.  But we must be sure that nothing is
             marked within OBJ before we really drop it.  */
          for (i = 0; i < size; i++)
-           if (VECTOR_MARKED_P (XFONT_ENTITY (AREF (XCDR (obj), i))))
-             break;
+            {
+              Lisp_Object objlist;
+
+              if (VECTOR_MARKED_P (XFONT_ENTITY (AREF (XCDR (obj), i))))
+                break;
+
+              objlist = AREF (AREF (XCDR (obj), i), FONT_OBJLIST_INDEX);
+              for (; CONSP (objlist); objlist = XCDR (objlist))
+                {
+                  Lisp_Object val = XCAR (objlist);
+                  struct font *font = XFONT_OBJECT (val);
+
+                  if (!NILP (AREF (val, FONT_TYPE_INDEX))
+                      && VECTOR_MARKED_P(font))
+                    break;
+                }
+              if (CONSP (objlist))
+               {
+                 /* Foiund a marked font, bail out.  */
+                 break;
+               }
+            }
 
          if (i == size)
-           drop = 1;
+           {
+             /* No marked fonts were found, so this entire font
+                entity can be dropped.  */
+             drop = 1;
+           }
        }
       if (drop)
        *prev = XCDR (tail);