mirror of
https://git.savannah.gnu.org/git/guile.git
synced 2025-04-30 20:00:19 +02:00
379 lines
8.9 KiB
C
379 lines
8.9 KiB
C
/* Copyright (C) 1995,1996,1997,1998,2000,2001, 2002, 2003, 2006, 2008 Free Software Foundation, Inc.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#if 0
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/* This whole file is not being compiled. See futures.h for the
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reason.
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*/
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#ifdef HAVE_CONFIG_H
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# include <config.h>
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#endif
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#include "libguile/_scm.h"
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#include "libguile/eval.h"
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#include "libguile/ports.h"
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#include "libguile/validate.h"
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#include "libguile/stime.h"
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#include "libguile/threads.h"
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#include "libguile/futures.h"
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#define LINK(list, obj) \
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do { \
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SCM_SET_FUTURE_NEXT (obj, list); \
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list = obj; \
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} while (0)
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#define UNLINK(list, obj) \
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do { \
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obj = list; \
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list = SCM_FUTURE_NEXT (list); \
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} while (0)
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scm_i_pthread_mutex_t future_admin_mutex = SCM_I_PTHREAD_MUTEX_INITIALIZER;
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static SCM futures = SCM_EOL;
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static SCM young = SCM_EOL;
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static SCM old = SCM_EOL;
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static SCM undead = SCM_EOL;
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static long last_switch;
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#ifdef SCM_FUTURES_DEBUG
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static int n_dead = 0;
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static SCM
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count (SCM ls)
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{
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int n = 0;
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while (!scm_is_null (ls))
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{
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++n;
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ls = SCM_FUTURE_NEXT (ls);
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}
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return scm_from_int (n);
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}
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extern SCM scm_future_cache_status (void);
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SCM_DEFINE (scm_future_cache_status, "future-cache-status", 0, 0, 0,
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(),
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"Return a list containing number of futures, youngs, olds, undeads and deads.")
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#define FUNC_NAME s_scm_future_cache_status
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{
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int nd = n_dead;
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n_dead = 0;
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return scm_list_5 (count (futures),
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count (young),
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count (old),
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count (undead),
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scm_from_int (nd));
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}
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#undef FUNC_NAME
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#endif
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SCM *scm_loc_sys_thread_handler;
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SCM_DEFINE (scm_make_future, "make-future", 1, 0, 0,
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(SCM thunk),
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"Make a future evaluating THUNK.")
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#define FUNC_NAME s_scm_make_future
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{
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SCM_VALIDATE_THUNK (1, thunk);
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return scm_i_make_future (thunk);
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}
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#undef FUNC_NAME
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static char *s_future = "future";
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static void
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cleanup (scm_t_future *future)
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{
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scm_i_pthread_mutex_destroy (&future->mutex);
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scm_i_pthread_cond_destroy (&future->cond);
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scm_gc_free (future, sizeof (*future), s_future);
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#ifdef SCM_FUTURES_DEBUG
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++n_dead;
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#endif
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}
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static SCM
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future_loop (scm_t_future *future)
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{
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scm_i_scm_pthread_mutex_lock (&future->mutex);
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do {
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if (future->status == SCM_FUTURE_SIGNAL_ME)
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scm_i_pthread_cond_broadcast (&future->cond);
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future->status = SCM_FUTURE_COMPUTING;
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future->data = (SCM_CLOSUREP (future->data)
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? scm_i_call_closure_0 (future->data)
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: scm_call_0 (future->data));
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scm_i_scm_pthread_cond_wait (&future->cond, &future->mutex);
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} while (!future->die_p);
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future->status = SCM_FUTURE_DEAD;
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scm_i_pthread_mutex_unlock (&future->mutex);
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return SCM_UNSPECIFIED;
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}
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static SCM
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future_handler (scm_t_future *future, SCM key, SCM args)
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{
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future->status = SCM_FUTURE_DEAD;
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scm_i_pthread_mutex_unlock (&future->mutex);
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return scm_apply_1 (*scm_loc_sys_thread_handler, key, args);
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}
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static SCM
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alloc_future (SCM thunk)
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{
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scm_t_future *f = scm_gc_malloc (sizeof (*f), s_future);
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SCM future;
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f->data = SCM_BOOL_F;
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scm_i_pthread_mutex_init (&f->mutex, NULL);
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scm_i_pthread_cond_init (&f->cond, NULL);
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f->die_p = 0;
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f->status = SCM_FUTURE_TASK_ASSIGNED;
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scm_i_scm_pthread_mutex_lock (&future_admin_mutex);
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SCM_NEWSMOB2 (future, scm_tc16_future, futures, f);
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SCM_SET_FUTURE_DATA (future, thunk);
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futures = future;
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scm_i_pthread_mutex_unlock (&future_admin_mutex);
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scm_spawn_thread ((scm_t_catch_body) future_loop,
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SCM_FUTURE (future),
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(scm_t_catch_handler) future_handler,
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SCM_FUTURE (future));
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return future;
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}
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static void
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kill_future (SCM future)
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{
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SCM_FUTURE (future)->die_p = 1;
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LINK (undead, future);
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}
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SCM
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scm_i_make_future (SCM thunk)
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{
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SCM future;
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scm_i_scm_pthread_mutex_lock (&future_admin_mutex);
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while (1)
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{
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if (!scm_is_null (old))
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UNLINK (old, future);
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else if (!scm_is_null (young))
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UNLINK (young, future);
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else
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{
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scm_i_pthread_mutex_unlock (&future_admin_mutex);
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return alloc_future (thunk);
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}
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if (scm_i_pthread_mutex_trylock (SCM_FUTURE_MUTEX (future)))
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kill_future (future);
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else if (!SCM_FUTURE_ALIVE_P (future))
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{
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scm_i_pthread_mutex_unlock (SCM_FUTURE_MUTEX (future));
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cleanup (SCM_FUTURE (future));
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}
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else
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break;
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}
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LINK (futures, future);
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scm_i_pthread_mutex_unlock (&future_admin_mutex);
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SCM_SET_FUTURE_DATA (future, thunk);
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SCM_SET_FUTURE_STATUS (future, SCM_FUTURE_TASK_ASSIGNED);
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scm_i_pthread_cond_signal (SCM_FUTURE_COND (future));
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scm_i_pthread_mutex_unlock (SCM_FUTURE_MUTEX (future));
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return future;
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}
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static SCM
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future_mark (SCM ptr) {
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return SCM_FUTURE_DATA (ptr);
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}
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static int
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future_print (SCM exp, SCM port, scm_print_state *pstate)
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{
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int writingp = SCM_WRITINGP (pstate);
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scm_puts ("#<future ", port);
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SCM_SET_WRITINGP (pstate, 1);
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scm_iprin1 (SCM_FUTURE_DATA (exp), port, pstate);
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SCM_SET_WRITINGP (pstate, writingp);
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scm_putc ('>', port);
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return !0;
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}
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SCM_DEFINE (scm_future_ref, "future-ref", 1, 0, 0,
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(SCM future),
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"If the future @var{x} has not been computed yet, compute and\n"
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"return @var{x}, otherwise just return the previously computed\n"
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"value.")
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#define FUNC_NAME s_scm_future_ref
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{
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SCM res;
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SCM_VALIDATE_FUTURE (1, future);
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scm_i_scm_pthread_mutex_lock (SCM_FUTURE_MUTEX (future));
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if (SCM_FUTURE_STATUS (future) != SCM_FUTURE_COMPUTING)
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{
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SCM_SET_FUTURE_STATUS (future, SCM_FUTURE_SIGNAL_ME);
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scm_i_scm_pthread_cond_wait (SCM_FUTURE_COND (future),
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SCM_FUTURE_MUTEX (future));
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}
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if (!SCM_FUTURE_ALIVE_P (future))
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{
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scm_i_pthread_mutex_unlock (SCM_FUTURE_MUTEX (future));
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SCM_MISC_ERROR ("requesting result from failed future ~A",
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scm_list_1 (future));
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}
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res = SCM_FUTURE_DATA (future);
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scm_i_pthread_mutex_unlock (SCM_FUTURE_MUTEX (future));
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return res;
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}
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#undef FUNC_NAME
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static void
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kill_futures (SCM victims)
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{
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while (!scm_is_null (victims))
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{
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SCM future;
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UNLINK (victims, future);
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kill_future (future);
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scm_i_pthread_cond_signal (SCM_FUTURE_COND (future));
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}
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}
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static void
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cleanup_undead ()
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{
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SCM next = undead, *nextloc = &undead;
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while (!scm_is_null (next))
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{
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if (scm_i_pthread_mutex_trylock (SCM_FUTURE_MUTEX (next)))
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goto next;
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else if (SCM_FUTURE_ALIVE_P (next))
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{
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scm_i_pthread_cond_signal (SCM_FUTURE_COND (next));
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scm_i_pthread_mutex_unlock (SCM_FUTURE_MUTEX (next));
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next:
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SCM_SET_GC_MARK (next);
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nextloc = SCM_FUTURE_NEXTLOC (next);
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next = *nextloc;
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}
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else
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{
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SCM future;
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UNLINK (next, future);
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scm_i_pthread_mutex_unlock (SCM_FUTURE_MUTEX (future));
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cleanup (SCM_FUTURE (future));
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*nextloc = next;
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}
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}
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}
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static void
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mark_futures (SCM futures)
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{
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while (!scm_is_null (futures))
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{
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SCM_SET_GC_MARK (futures);
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futures = SCM_FUTURE_NEXT (futures);
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}
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}
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static void *
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scan_futures (void *dummy1, void *dummy2, void *dummy3)
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{
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SCM next, *nextloc;
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long now = scm_c_get_internal_run_time ();
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if (now - last_switch > SCM_TIME_UNITS_PER_SECOND)
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{
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/* switch out old (> 1 sec), unused futures */
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kill_futures (old);
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old = young;
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young = SCM_EOL;
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last_switch = now;
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}
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else
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mark_futures (young);
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next = futures;
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nextloc = &futures;
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while (!scm_is_null (next))
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{
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if (!SCM_GC_MARK_P (next))
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goto free;
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keep:
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nextloc = SCM_FUTURE_NEXTLOC (next);
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next = *nextloc;
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}
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goto exit;
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while (!scm_is_null (next))
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{
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if (SCM_GC_MARK_P (next))
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{
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*nextloc = next;
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goto keep;
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}
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free:
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{
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SCM future;
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UNLINK (next, future);
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SCM_SET_GC_MARK (future);
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LINK (young, future);
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}
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}
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*nextloc = SCM_EOL;
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exit:
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cleanup_undead ();
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mark_futures (old);
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return 0;
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}
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scm_t_bits scm_tc16_future;
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void
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scm_init_futures ()
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{
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last_switch = scm_c_get_internal_run_time ();
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scm_loc_sys_thread_handler
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= SCM_VARIABLE_LOC (scm_c_define ("%thread-handler", SCM_BOOL_F));
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scm_tc16_future = scm_make_smob_type ("future", 0);
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scm_set_smob_mark (scm_tc16_future, future_mark);
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scm_set_smob_print (scm_tc16_future, future_print);
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scm_c_hook_add (&scm_before_sweep_c_hook, scan_futures, 0, 0);
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#include "libguile/futures.x"
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}
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#endif
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/*
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Local Variables:
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c-file-style: "gnu"
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End:
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*/
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