[Bug-guile-ncurses] [PATCH 1/2] Add reference count to ITEM structs contained by SCMs

[John Darrington]

* ncurses/menu_type.c (_scm_from_item, new_item, free_item): Add reference 
counting.
---
 ncurses/menu_type.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/ncurses/menu_type.c b/ncurses/menu_type.c
index 679e9c1..712cd35 100644
--- a/ncurses/menu_type.c
+++ b/ncurses/menu_type.c
@@ -88,6 +88,8 @@ gucu_new_item (SCM name, SCM description)
        abort ();
     }
 
+  /* Use the userptr member as a reference count */
+  set_item_userptr (c_item, 0);
   SCM ret = _scm_from_item (c_item);
 
   return ret;
@@ -117,6 +119,9 @@ _scm_from_item (ITEM * x)
 
   assert (x == (ITEM *) SCM_SMOB_DATA (s_item));
 
+  intptr_t refcnt = (intptr_t) item_userptr (x);
+  set_item_userptr (x, (void *) (++refcnt));
+  
   if (0)
     {
       fprintf (stderr, "Making <#item> smob from ITEM * %p\n", (void *) x);
@@ -157,7 +162,11 @@ gc_free_item (SCM item)
 
   assert (m != NULL);
 
-  free_item (m);
+  intptr_t refcnt = (intptr_t) item_userptr (m);
+  set_item_userptr (m, (void *) (--refcnt));
+
+  if (refcnt == 0)
+    free_item (m);
 
   return 0;
 }
-- 
2.1.4