/* classes: h_files */

#ifndef SCM_THREADS_H
#define SCM_THREADS_H

/* Copyright (C) 1996,1997,1998,2000,2001, 2002, 2003 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 2.1 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */



#include "libguile/__scm.h"
#include "libguile/procs.h"
#include "libguile/throw.h"
#include "libguile/root.h"
#include "libguile/iselect.h"
#include "libguile/threads-plugin.h"


/* smob tags for the thread datatypes */
SCM_API scm_t_bits scm_tc16_thread;
SCM_API scm_t_bits scm_tc16_mutex;
SCM_API scm_t_bits scm_tc16_fair_mutex;
SCM_API scm_t_bits scm_tc16_condvar;
SCM_API scm_t_bits scm_tc16_fair_condvar;

#define SCM_THREADP(x)        SCM_SMOB_PREDICATE (scm_tc16_thread, x)
#define SCM_THREAD_DATA(x)    ((scm_thread *) SCM_SMOB_DATA (x))

#define SCM_MUTEXP(x)         SCM_SMOB_PREDICATE (scm_tc16_mutex, x)
#define SCM_FAIR_MUTEX_P(x)   SCM_SMOB_PREDICATE (scm_tc16_fair_mutex, x)
#define SCM_MUTEX_DATA(x)     ((void *) SCM_SMOB_DATA (x))

#define SCM_CONDVARP(x)       SCM_SMOB_PREDICATE (scm_tc16_condvar, x)
#define SCM_FAIR_CONDVAR_P(x) SCM_SMOB_PREDICATE (scm_tc16_fair_condvar, x)
#define SCM_CONDVAR_DATA(x)   ((void *) SCM_SMOB_DATA (x))

#define SCM_VALIDATE_THREAD(pos, a) \
 SCM_MAKE_VALIDATE_MSG (pos, a, THREADP, "thread")

#define SCM_VALIDATE_MUTEX(pos, a) \
 SCM_ASSERT_TYPE (SCM_MUTEXP (a) || SCM_FAIR_MUTEX_P (a), \
                  a, pos, FUNC_NAME, "mutex");

#define SCM_VALIDATE_CONDVAR(pos, a) \
 SCM_ASSERT_TYPE (SCM_CONDVARP (a) || SCM_FAIR_CONDVAR_P (a), \
                  a, pos, FUNC_NAME, "condition variable");

SCM_API void scm_threads_mark_stacks (void);
SCM_API void scm_init_threads (SCM_STACKITEM *);
SCM_API void scm_init_thread_procs (void);

#if SCM_USE_PTHREAD_THREADS
# include "libguile/pthread-threads.h"
#else
# include "libguile/null-threads.h"
#endif

/*----------------------------------------------------------------------*/
/* Low-level C API */

/* The purpose of this API is seamless, simple and thread package
   independent interaction with Guile threads from the application.

   Note that Guile also uses it to implement itself, just like
   with the rest of the application API.
 */

/* MDJ 021209 <djurfeldt@nada.kth.se>:
   The separation of the plugin interface (currently in
   pthread-threads.h and null-threads.h) and the low-level C API needs
   to be completed in a sensible way.
 */

/* Deprecate this name and rename to scm_thread_create?
   Introduce the other two arguments in pthread_create to prepare for
   the future?
 */
SCM_API SCM scm_spawn_thread (scm_t_catch_body body, void *body_data,
			      scm_t_catch_handler handler, void *handler_data);
SCM_API scm_t_thread scm_c_scm2thread (SCM thread);

#define scm_thread_join		scm_i_plugin_thread_join
#define scm_thread_detach	scm_i_plugin_thread_detach
#define scm_thread_self		scm_i_plugin_thread_self
#define scm_thread_yield	scm_i_plugin_thread_yield

#define scm_mutex_init		scm_i_plugin_mutex_init 
#define scm_mutex_destroy	scm_i_plugin_mutex_destroy
SCM_API int scm_mutex_lock (scm_t_mutex *m);
#define scm_mutex_trylock	scm_i_plugin_mutex_trylock 
#define scm_mutex_unlock	scm_i_plugin_mutex_unlock 

/* Guile itself needs recursive mutexes.  See for example the
   implentation of scm_force in eval.c.

   Note that scm_rec_mutex_lock et al can be replaced by direct usage
   of the corresponding pthread functions if we use the pthread
   debugging API to access the stack top (in which case there is no
   longer any need to save the top of the stack before blocking).

   It's therefore highly motivated to use these calls in situations
   where Guile or the application needs recursive mutexes.
 */
#define scm_rec_mutex_init	scm_i_plugin_rec_mutex_init
#define scm_rec_mutex_destroy	scm_i_plugin_rec_mutex_destroy
/* It's a safer bet to use the following functions.
   The future of the _init functions is uncertain.
 */
SCM_API scm_t_rec_mutex *scm_make_rec_mutex (void);
SCM_API void scm_rec_mutex_free (scm_t_rec_mutex *);
SCM_API int scm_rec_mutex_lock (scm_t_rec_mutex *m);
#define scm_rec_mutex_trylock	scm_i_plugin_rec_mutex_trylock 
#define scm_rec_mutex_unlock	scm_i_plugin_rec_mutex_unlock 

#define scm_cond_init		scm_i_plugin_cond_init 
#define scm_cond_destroy	scm_i_plugin_cond_destroy 
SCM_API int scm_cond_wait (scm_t_cond *c, scm_t_mutex *m);
SCM_API int scm_cond_timedwait (scm_t_cond *c,
				scm_t_mutex *m,
				const scm_t_timespec *t);
#define scm_cond_signal		scm_i_plugin_cond_signal 
#define scm_cond_broadcast	scm_i_plugin_cond_broadcast 

#define scm_key_create		scm_i_plugin_key_create 
#define scm_key_delete		scm_i_plugin_key_delete 
SCM_API int scm_setspecific (scm_t_key k, void *s);
SCM_API void *scm_getspecific (scm_t_key k);

#define scm_thread_select	scm_internal_select

/* The application must scm_leave_guile() before entering any piece of
   code which can
   1. block, or
   2. execute for any longer period of time without calling SCM_TICK

   Note, though, that it is *not* necessary to use these calls
   together with any call in this API.
 */

SCM_API void scm_enter_guile (void);
SCM_API void scm_leave_guile (void);

/* Better versions (although we need the former ones also in order to
   avoid forcing code restructuring in existing applications): */
/*fixme* Not implemented yet! */
SCM_API void *scm_in_guile (void (*func) (void*), void *data);
SCM_API void *scm_outside_guile (void (*func) (void*), void *data);

/* These are versions of the ordinary sleep and usleep functions
   that play nicely with the thread system.  */
SCM_API unsigned long scm_thread_sleep (unsigned long);
SCM_API unsigned long scm_thread_usleep (unsigned long);

/* End of low-level C API */
/*----------------------------------------------------------------------*/

typedef struct scm_thread scm_thread;

SCM_API void scm_i_enter_guile (scm_thread *t);
SCM_API scm_thread *scm_i_leave_guile (void);

/* Critical sections */

/* This is the generic critical section for places where we are too
   lazy to allocate a specific mutex. */
extern scm_t_mutex scm_i_critical_section_mutex;

#define SCM_CRITICAL_SECTION_START \
  scm_mutex_lock (&scm_i_critical_section_mutex)
#define SCM_CRITICAL_SECTION_END \
  scm_mutex_unlock (&scm_i_critical_section_mutex)

/* This is the temporary support for the old ALLOW/DEFER ints sections */
extern scm_t_rec_mutex scm_i_defer_mutex;

extern int scm_i_thread_go_to_sleep;

void scm_i_thread_put_to_sleep (void);
void scm_i_thread_wake_up (void);
void scm_i_thread_invalidate_freelists (void);
void scm_i_thread_sleep_for_gc (void);
void scm_threads_prehistory (void);
void scm_threads_init_first_thread (void);

#define SCM_THREAD_SWITCHING_CODE \
do { \
  if (scm_i_thread_go_to_sleep) \
    scm_i_thread_sleep_for_gc (); \
} while (0)

SCM scm_i_create_thread (scm_t_catch_body body, void *body_data,
			 scm_t_catch_handler handler, void *handler_data,
			 SCM protects);

/* The C versions of the Scheme-visible thread functions.  */
SCM_API SCM scm_call_with_new_thread (SCM thunk, SCM handler);
SCM_API SCM scm_yield (void);
SCM_API SCM scm_join_thread (SCM t);
SCM_API SCM scm_make_mutex (void);
SCM_API SCM scm_make_fair_mutex (void);
SCM_API SCM scm_lock_mutex (SCM m);
SCM_API SCM scm_try_mutex (SCM m);
SCM_API SCM scm_unlock_mutex (SCM m);
SCM_API SCM scm_make_condition_variable (void);
SCM_API SCM scm_make_fair_condition_variable (void);
SCM_API SCM scm_wait_condition_variable (SCM cond, SCM mutex);
SCM_API SCM scm_timed_wait_condition_variable (SCM cond, SCM mutex,
					       SCM abstime);
SCM_API SCM scm_signal_condition_variable (SCM cond);
SCM_API SCM scm_broadcast_condition_variable (SCM cond);

SCM_API SCM scm_current_thread (void);
SCM_API SCM scm_all_threads (void);

SCM_API int scm_c_thread_exited_p (SCM thread);
SCM_API SCM scm_thread_exited_p (SCM thread);

SCM_API scm_root_state *scm_i_thread_root (SCM thread);

#define SCM_CURRENT_THREAD \
  ((scm_thread *) scm_i_plugin_getspecific (scm_i_thread_key))
extern scm_t_key scm_i_thread_key;

/* These macros have confusing names.
   They really refer to the root state of the running thread. */
#define SCM_THREAD_LOCAL_DATA (scm_getspecific (scm_i_root_state_key))
#define SCM_SET_THREAD_LOCAL_DATA(x) scm_i_set_thread_data(x)
SCM_API scm_t_key scm_i_root_state_key;
SCM_API void scm_i_set_thread_data (void *);

#endif  /* SCM_THREADS_H */

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