Re: Memory leak in keyboard variables?

[Chong Yidong <cyd@stupidchicken.com>]

Kenichi Handa <handa@m17n.org> writes:

> The strategy is to record all font-objects in font-entities, and
> record all font-entities in a cache of each font-backend.  The caches
> are freed when `delete-frame' calls font_update_drivers with
> new_drivers as nil

Thanks for the explanation.  It was very helpful.

I think the problem is that font_clear_cache is incorrectly written.
For some reason, it assumes that the font cache entries have the form

  (font-spec [entity1 entity2...])

when in fact, they have the form

  (font-spec entity1 entity2...)

The following patch to font_clear_cache frees 60-70k of memory per
terminal.

Do you know why font_clear_cache was written this way, and whether there
could be any other places in the font code that make this incorrect
assumption?

*** trunk/src/font.c.~1.99.~	2008-12-13 10:39:30.000000000 -0500
--- trunk/src/font.c	2008-12-14 22:06:26.000000000 -0500
***************
*** 2651,2671 ****
       struct font_driver *driver;
  {
    Lisp_Object tail, elt;
  
    /* CACHE = (DRIVER-TYPE NUM-FRAMES FONT-CACHE-DATA ...) */
    for (tail = XCDR (XCDR (cache)); CONSP (tail); tail = XCDR (tail))
      {
        elt = XCAR (tail);
!       if (CONSP (elt) && FONT_SPEC_P (XCAR (elt)) && VECTORP (XCDR (elt)))
  	{
! 	  Lisp_Object vec = XCDR (elt);
! 	  int i;
! 
! 	  for (i = 0; i < ASIZE (vec); i++)
  	    {
! 	      Lisp_Object entity = AREF (vec, i);
  
! 	      if (EQ (driver->type, AREF (entity, FONT_TYPE_INDEX)))
  		{
  		  Lisp_Object objlist = AREF (entity, FONT_OBJLIST_INDEX);
  
--- 2651,2671 ----
       struct font_driver *driver;
  {
    Lisp_Object tail, elt;
+   Lisp_Object tail2, entity;
  
    /* CACHE = (DRIVER-TYPE NUM-FRAMES FONT-CACHE-DATA ...) */
    for (tail = XCDR (XCDR (cache)); CONSP (tail); tail = XCDR (tail))
      {
        elt = XCAR (tail);
!       /* elt should have the form (FONT-SPEC FONT-ENTITY ...) */
!       if (CONSP (elt) && FONT_SPEC_P (XCAR (elt)))
  	{
! 	  for (tail2 = XCDR (elt); CONSP (tail2); tail2 = XCDR (tail2))
  	    {
! 	      entity = XCAR (tail2);
  
! 	      if (FONT_ENTITY_P (entity)
! 		  && EQ (driver->type, AREF (entity, FONT_TYPE_INDEX)))
  		{
  		  Lisp_Object objlist = AREF (entity, FONT_OBJLIST_INDEX);