Fix bug #27450 ("Fat mutexes not GC'd until their owner dies").

[bpt/guile.git] / libguile / weaks.h

/* classes: h_files */

#ifndef SCM_WEAKS_H
#define SCM_WEAKS_H

/* Copyright (C) 1995,1996,2000,2001, 2003, 2006, 2008, 2009 Free Software Foundation, Inc.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public License
 * as published by the Free Software Foundation; either version 3 of
 * the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301 USA
 */

\f

#include "libguile/__scm.h"

\f

#define SCM_WVECTF_WEAK_KEY   1
#define SCM_WVECTF_WEAK_VALUE 2

#define SCM_WVECT_WEAK_KEY_P(x) (SCM_I_WVECT_EXTRA(x) & SCM_WVECTF_WEAK_KEY)
#define SCM_WVECT_WEAK_VALUE_P(x) (SCM_I_WVECT_EXTRA(x) & SCM_WVECTF_WEAK_VALUE)

/* The DELTA field is used by the abstract hash tables.  During GC,
   this field will be set to the number of items that have been
   dropped.  The abstract hash table will then use it to update its
   item count.  DELTA is unsigned.
*/

#define SCM_I_WVECT_DELTA(x)       (SCM_I_WVECT_EXTRA(x) >> 3)
#define SCM_I_SET_WVECT_DELTA(x,n) (SCM_I_SET_WVECT_EXTRA \
				    ((x), ((SCM_I_WVECT_EXTRA (x) & 7)	\
					   | ((n) << 3))))

#define SCM_I_WVECT_TYPE(x)       (SCM_I_WVECT_EXTRA(x) & 7)
#define SCM_I_SET_WVECT_TYPE(x,t) (SCM_I_SET_WVECT_EXTRA		\
				   ((x), (SCM_I_WVECT_EXTRA (x) & ~7) | (t)))
#define SCM_IS_WHVEC(X)           (SCM_I_WVECT_TYPE (X) == 1)
#define SCM_IS_WHVEC_V(X)         (SCM_I_WVECT_TYPE (X) == 2)
#define SCM_IS_WHVEC_B(X)         (SCM_I_WVECT_TYPE (X) == 3)
#define SCM_IS_WHVEC_ANY(X)       (SCM_I_WVECT_TYPE (X) != 0)

\f
/* Weak pairs.  */

SCM_API SCM scm_weak_car_pair (SCM car, SCM cdr);
SCM_API SCM scm_weak_cdr_pair (SCM car, SCM cdr);
SCM_API SCM scm_doubly_weak_pair (SCM car, SCM cdr);

/* Testing the weak component(s) of a cell for reachability.  */
#define SCM_WEAK_PAIR_WORD_DELETED_P(_cell, _word)		\
  (SCM_CELL_OBJECT ((_cell), (_word)) == SCM_PACK (NULL))
#define SCM_WEAK_PAIR_CAR_DELETED_P(_cell)	\
  (SCM_WEAK_PAIR_WORD_DELETED_P ((_cell), 0))
#define SCM_WEAK_PAIR_CDR_DELETED_P(_cell)	\
  (SCM_WEAK_PAIR_WORD_DELETED_P ((_cell), 1))

#define SCM_WEAK_PAIR_DELETED_P(_cell)		\
  ((SCM_WEAK_PAIR_CAR_DELETED_P (_cell))	\
   || (SCM_WEAK_PAIR_CDR_DELETED_P (_cell)))

/* Accessing the components of a weak cell.  These return `SCM_UNDEFINED' if
   the car/cdr has been collected.  */
#define SCM_WEAK_PAIR_WORD(_cell, _word)		\
  (SCM_WEAK_PAIR_WORD_DELETED_P ((_cell), (_word))	\
   ? SCM_UNDEFINED					\
   : SCM_CELL_OBJECT ((_cell), (_word)))
#define SCM_WEAK_PAIR_CAR(_cell)  (SCM_WEAK_PAIR_WORD ((_cell), 0))
#define SCM_WEAK_PAIR_CDR(_cell)  (SCM_WEAK_PAIR_WORD ((_cell), 1))


\f
/* Weak vectors and weak hash tables.  */

SCM_API SCM scm_make_weak_vector (SCM k, SCM fill);
SCM_API SCM scm_weak_vector (SCM l);
SCM_API SCM scm_weak_vector_p (SCM x);
SCM_API SCM scm_make_weak_key_alist_vector (SCM k);
SCM_API SCM scm_make_weak_value_alist_vector (SCM k);
SCM_API SCM scm_make_doubly_weak_alist_vector (SCM k);
SCM_API SCM scm_weak_key_alist_vector_p (SCM x);
SCM_API SCM scm_weak_value_alist_vector_p (SCM x);
SCM_API SCM scm_doubly_weak_alist_vector_p (SCM x);
SCM_INTERNAL SCM scm_init_weaks_builtins (void);
SCM_INTERNAL void scm_weaks_prehistory (void);
SCM_INTERNAL void scm_init_weaks (void);

SCM_INTERNAL void scm_i_init_weak_vectors_for_gc (void);
SCM_INTERNAL void scm_i_mark_weak_vector (SCM w);
SCM_INTERNAL int scm_i_mark_weak_vectors_non_weaks (void);
SCM_INTERNAL void scm_i_remove_weaks_from_weak_vectors (void);


#endif  /* SCM_WEAKS_H */

/*
  Local Variables:
  c-file-style: "gnu"
  End:
*/