-/* Copyright (C) 1995, 96, 97, 98, 2000 Free Software Foundation, Inc.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2, or (at your option)
- * any later version.
- *
- * This program 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 General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this software; see the file COPYING. If not, write to
- * the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
- * Boston, MA 02111-1307 USA
- *
- * As a special exception, the Free Software Foundation gives permission
- * for additional uses of the text contained in its release of GUILE.
- *
- * The exception is that, if you link the GUILE library with other files
- * to produce an executable, this does not by itself cause the
- * resulting executable to be covered by the GNU General Public License.
- * Your use of that executable is in no way restricted on account of
- * linking the GUILE library code into it.
- *
- * This exception does not however invalidate any other reasons why
- * the executable file might be covered by the GNU General Public License.
- *
- * This exception applies only to the code released by the
- * Free Software Foundation under the name GUILE. If you copy
- * code from other Free Software Foundation releases into a copy of
- * GUILE, as the General Public License permits, the exception does
- * not apply to the code that you add in this way. To avoid misleading
- * anyone as to the status of such modified files, you must delete
- * this exception notice from them.
- *
- * If you write modifications of your own for GUILE, it is your choice
- * whether to permit this exception to apply to your modifications.
- * If you do not wish that, delete this exception notice. */
-
-/* Software engineering face-lift by Greg J. Badros, 11-Dec-1999,
- gjb@cs.washington.edu, http://www.cs.washington.edu/homes/gjb */
-
-\f
-
-#include <stdio.h>
-#include <signal.h>
-#include "libguile/_scm.h"
-#include "libguile/eval.h"
-#include "libguile/throw.h"
-#include "libguile/root.h"
-#include "libguile/smob.h"
-#include "libguile/gc.h"
-
-#include "libguile/validate.h"
-#include "libguile/async.h"
-
-#ifdef HAVE_STRING_H
-#include <string.h>
-#endif
-#ifdef HAVE_UNISTD_H
-#include <unistd.h>
-#endif
-
-
-\f
-/* {Asynchronous Events}
- *
- *
- * Async == thunk + mark.
- *
- * Setting the mark guarantees future execution of the thunk. More
- * than one set may be satisfied by a single execution.
- *
- * scm_tick_clock decremented once per SCM_ALLOW_INTS.
- * Async execution triggered by SCM_ALLOW_INTS when scm_tick_clock drops to 0.
- * Async execution prevented by scm_mask_ints != 0.
- *
- * If the clock reaches 0 when scm_mask_ints != 0, then reset the clock
- * to 1.
- *
- * If the clock reaches 0 any other time, run marked asyncs.
- *
- * From a unix signal handler, mark a corresponding async and set the clock
- * to 1. Do SCM_REDEFER_INTS;/SCM_REALLOW_INTS so that if the signal handler is not
- * called in the dynamic scope of a critical section, it is excecuted immediately.
- *
- * Overall, closely timed signals of a particular sort may be combined. Pending signals
- * are delivered in a fixed priority order, regardless of arrival order.
- *
- */
-
-/* True between SCM_DEFER_INTS and SCM_ALLOW_INTS, and
- * when the interpreter is not running at all.
- */
-int scm_ints_disabled = 1;
-unsigned int scm_mask_ints = 1;
-
-#ifdef GUILE_OLD_ASYNC_CLICK
-unsigned int scm_async_clock = 20;
-static unsigned int scm_async_rate = 20;
-
-static unsigned int scm_tick_clock = 0;
-static unsigned int scm_tick_rate = 0;
-static unsigned int scm_desired_tick_rate = 0;
-static unsigned int scm_switch_clock = 0;
-static unsigned int scm_switch_rate = 0;
-static unsigned int scm_desired_switch_rate = 0;
-#else
-int scm_asyncs_pending_p = 0;
-#endif
-
-static long tc16_async;
-
-\f
-
-/* cmm: this has SCM_ prefix because SCM_MAKE_VALIDATE expects it.
- this is ugly. */
-#define SCM_ASYNCP(X) (SCM_NIMP(X) && (tc16_async == SCM_GCTYP16 (X)))
-
-#define VALIDATE_ASYNC(pos,a) SCM_MAKE_VALIDATE(pos, a, ASYNCP)
-
-#define ASYNC_GOT_IT(X) (SCM_CELL_WORD_0 (X) >> 16)
-#define SET_ASYNC_GOT_IT(X, V) (SCM_SET_CELL_WORD_0 (X, (SCM_CELL_WORD_0 (X) & ((1 << 16) - 1)) | ((V) << 16)))
-#define ASYNC_THUNK(X) SCM_CELL_OBJECT_1 (X)
-
-\f
-
-#ifdef GUILE_OLD_ASYNC_CLICK
-int
-scm_asyncs_pending ()
-{
- SCM pos;
- pos = scm_asyncs;
- while (pos != SCM_EOL)
- {
- SCM a = SCM_CAR (pos);
- if (ASYNC_GOT_IT (a))
- return 1;
- pos = SCM_CDR (pos);
- }
- return 0;
-}
-
-#if 0
-static SCM
-scm_sys_tick_async_thunk (void)
-{
- scm_deliver_signal (SCM_TICK_SIGNAL);
- return SCM_BOOL_F;
-}
-#endif
-
-void
-scm_async_click ()
-{
- int owe_switch;
- int owe_tick;
-
- if (!scm_switch_rate)
- {
- owe_switch = 0;
- scm_switch_clock = scm_switch_rate = scm_desired_switch_rate;
- scm_desired_switch_rate = 0;
- }
- else
- {
- owe_switch = (scm_async_rate >= scm_switch_clock);
- if (owe_switch)
- {
- if (scm_desired_switch_rate)
- {
- scm_switch_clock = scm_switch_rate = scm_desired_switch_rate;
- scm_desired_switch_rate = 0;
- }
- else
- scm_switch_clock = scm_switch_rate;
- }
- else
- {
- if (scm_desired_switch_rate)
- {
- scm_switch_clock = scm_switch_rate = scm_desired_switch_rate;
- scm_desired_switch_rate = 0;
- }
- else
- scm_switch_clock -= scm_async_rate;
- }
- }
-
- if (scm_mask_ints)
- {
- if (owe_switch)
- scm_switch ();
- scm_async_clock = 1;
- return;;
- }
-
- if (!scm_tick_rate)
- {
- unsigned int r;
- owe_tick = 0;
- r = scm_desired_tick_rate;
- if (r)
- {
- scm_desired_tick_rate = 0;
- scm_tick_rate = r;
- scm_tick_clock = r;
- }
- }
- else
- {
- owe_tick = (scm_async_rate >= scm_tick_clock);
- if (owe_tick)
- {
- scm_tick_clock = scm_tick_rate = scm_desired_tick_rate;
- scm_desired_tick_rate = 0;
- }
- else
- {
- if (scm_desired_tick_rate)
- {
- scm_tick_clock = scm_tick_rate = scm_desired_tick_rate;
- scm_desired_tick_rate = 0;
- }
- else
- scm_tick_clock -= scm_async_rate;
- }
- }
-
- /*
- if (owe_tick)
- scm_async_mark (system_signal_asyncs[SCM_SIG_ORD(SCM_TICK_SIGNAL)]); */
-
- SCM_DEFER_INTS;
- if (scm_tick_rate && scm_switch_rate)
- {
- scm_async_rate = min (scm_tick_clock, scm_switch_clock);
- scm_async_clock = scm_async_rate;
- }
- else if (scm_tick_rate)
- {
- scm_async_clock = scm_async_rate = scm_tick_clock;
- }
- else if (scm_switch_rate)
- {
- scm_async_clock = scm_async_rate = scm_switch_clock;
- }
- else
- scm_async_clock = scm_async_rate = 1 << 16;
- SCM_ALLOW_INTS_ONLY;
-
- tail:
- scm_run_asyncs (scm_asyncs);
-
- SCM_DEFER_INTS;
- if (scm_asyncs_pending ())
- {
- SCM_ALLOW_INTS_ONLY;
- goto tail;
- }
- SCM_ALLOW_INTS;
-
- if (owe_switch)
- scm_switch ();
-}
-
-void
-scm_switch ()
-{
-#if 0 /* Thread switching code should probably reside here, but the
- async switching code doesn't seem to work, so it's put in the
- SCM_DEFER_INTS macro instead. /mdj */
- SCM_THREAD_SWITCHING_CODE;
-#endif
-}
-
-#else
-
-void
-scm_async_click ()
-{
- if (!scm_mask_ints)
- do
- scm_run_asyncs (scm_asyncs);
- while (scm_asyncs_pending_p);
-}
-
-#endif
-
-
-\f
-
-static SCM
-mark_async (SCM obj)
-{
- return ASYNC_THUNK (obj);
-}
-
-\f
-
-SCM_DEFINE (scm_async, "async", 1, 0, 0,
- (SCM thunk),
-"")
-#define FUNC_NAME s_scm_async
-{
- SCM_RETURN_NEWSMOB (tc16_async, SCM_UNPACK (thunk));
-}
-#undef FUNC_NAME
-
-SCM_DEFINE (scm_system_async, "system-async", 1, 0, 0,
- (SCM thunk),
-"")
-#define FUNC_NAME s_scm_system_async
-{
- SCM it;
- SCM list;
-
- it = scm_async (thunk);
- SCM_NEWCELL (list);
- SCM_SETCAR (list, it);
- SCM_SETCDR (list, scm_asyncs);
- scm_asyncs = list;
- return it;
-}
-#undef FUNC_NAME
-
-SCM_DEFINE (scm_async_mark, "async-mark", 1, 0, 0,
- (SCM a),
-"")
-#define FUNC_NAME s_scm_async_mark
-{
- VALIDATE_ASYNC (1, a);
-#ifdef GUILE_OLD_ASYNC_CLICK
- SET_ASYNC_GOT_IT (a, 1);
-#else
- SET_ASYNC_GOT_IT (a, scm_asyncs_pending_p = 1);
-#endif
- return SCM_UNSPECIFIED;
-}
-#undef FUNC_NAME
-
-
-SCM_DEFINE (scm_system_async_mark, "system-async-mark", 1, 0, 0,
- (SCM a),
-"")
-#define FUNC_NAME s_scm_system_async_mark
-{
- VALIDATE_ASYNC (1, a);
- SCM_REDEFER_INTS;
-#ifdef GUILE_OLD_ASYNC_CLICK
- SET_ASYNC_GOT_IT (a, 1);
- scm_async_rate = 1 + scm_async_rate - scm_async_clock;
- scm_async_clock = 1;
-#else
- SET_ASYNC_GOT_IT (a, scm_asyncs_pending_p = 1);
-#endif
- SCM_REALLOW_INTS;
- return SCM_UNSPECIFIED;
-}
-#undef FUNC_NAME
-
-
-SCM_DEFINE (scm_run_asyncs, "run-asyncs", 1, 0, 0,
- (SCM list_of_a),
-"")
-#define FUNC_NAME s_scm_run_asyncs
-{
-#ifdef GUILE_OLD_ASYNC_CLICK
- if (scm_mask_ints)
- return SCM_BOOL_F;
-#else
- scm_asyncs_pending_p = 0;
-#endif
- while (! SCM_NULLP (list_of_a))
- {
- SCM a;
- SCM_VALIDATE_CONS (1, list_of_a);
- a = SCM_CAR (list_of_a);
- VALIDATE_ASYNC (SCM_ARG1, a);
- scm_mask_ints = 1;
- if (ASYNC_GOT_IT (a))
- {
- SET_ASYNC_GOT_IT (a, 0);
- scm_apply (ASYNC_THUNK (a), SCM_EOL, SCM_EOL);
- }
- scm_mask_ints = 0;
- list_of_a = SCM_CDR (list_of_a);
- }
- return SCM_BOOL_T;
-}
-#undef FUNC_NAME
-
-\f
-
-
-SCM_DEFINE (scm_noop, "noop", 0, 0, 1,
- (SCM args),
-"")
-#define FUNC_NAME s_scm_noop
-{
- SCM_VALIDATE_REST_ARGUMENT (args);
- return (SCM_NULLP (args) ? SCM_BOOL_F : SCM_CAR (args));
-}
-#undef FUNC_NAME
-
-
-\f
-
-#ifdef GUILE_OLD_ASYNC_CLICK
-
-SCM_DEFINE (scm_set_tick_rate, "set-tick-rate", 1, 0, 0,
- (SCM n),
-"")
-#define FUNC_NAME s_scm_set_tick_rate
-{
- unsigned int old_n = scm_tick_rate;
- SCM_VALIDATE_INUM (1, n);
- scm_desired_tick_rate = SCM_INUM (n);
- scm_async_rate = 1 + scm_async_rate - scm_async_clock;
- scm_async_clock = 1;
- return SCM_MAKINUM (old_n);
-}
-#undef FUNC_NAME
-
-\f
-
-
-SCM_DEFINE (scm_set_switch_rate, "set-switch-rate", 1, 0, 0,
- (SCM n),
-"")
-#define FUNC_NAME s_scm_set_switch_rate
-{
- unsigned int old_n = scm_switch_rate;
- SCM_VALIDATE_INUM (1, n);
- scm_desired_switch_rate = SCM_INUM (n);
- scm_async_rate = 1 + scm_async_rate - scm_async_clock;
- scm_async_clock = 1;
- return SCM_MAKINUM (old_n);
-}
-#undef FUNC_NAME
-
-#endif
-\f
-
-/* points to the GC system-async, so that scm_gc_end can find it. */
-SCM scm_gc_async;
-
-/* the vcell for gc-thunk. */
-static SCM scm_gc_vcell;
-
-/* the thunk installed in the GC system-async, which is marked at the
- end of garbage collection. */
-static SCM
-scm_sys_gc_async_thunk (void)
-{
- scm_c_run_hook (scm_after_gc_hook, SCM_EOL);
-
-#if (SCM_DEBUG_DEPRECATED == 0)
-
- /* The following code will be removed in Guile 1.5. */
- if (SCM_NFALSEP (scm_gc_vcell))
- {
- SCM proc = SCM_CDR (scm_gc_vcell);
-
- if (SCM_NFALSEP (proc) && !SCM_UNBNDP (proc))
- scm_apply (proc, SCM_EOL, SCM_EOL);
- }
-
-#endif /* SCM_DEBUG_DEPRECATED == 0 */
-
- return SCM_UNSPECIFIED;
-}
-
-\f
-
-SCM_DEFINE (scm_unmask_signals, "unmask-signals", 0, 0, 0,
- (),
-"")
-#define FUNC_NAME s_scm_unmask_signals
-{
- scm_mask_ints = 0;
- return SCM_UNSPECIFIED;
-}
-#undef FUNC_NAME
-
-
-SCM_DEFINE (scm_mask_signals, "mask-signals", 0, 0, 0,
- (),
-"")
-#define FUNC_NAME s_scm_mask_signals
-{
- scm_mask_ints = 1;
- return SCM_UNSPECIFIED;
-}
-#undef FUNC_NAME
-
-\f
-
-void
-scm_init_async ()
-{
- SCM a_thunk;
- tc16_async = scm_make_smob_type_mfpe ("async", 0,
- mark_async, NULL, NULL, NULL);
- scm_gc_vcell = scm_sysintern ("gc-thunk", SCM_BOOL_F);
- a_thunk = scm_make_gsubr ("%gc-thunk", 0, 0, 0, scm_sys_gc_async_thunk);
- scm_gc_async = scm_system_async (a_thunk);
-
-#include "libguile/async.x"
-}
-
-/*
- Local Variables:
- c-file-style: "gnu"
- End:
-*/
+/* Copyright (C) 1995,1996,1997,1998,2000,2001, 2002, 2004, 2006, 2008, 2009, 2010, 2011 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
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#include "libguile/_scm.h"
+#include "libguile/eval.h"
+#include "libguile/throw.h"
+#include "libguile/root.h"
+#include "libguile/smob.h"
+#include "libguile/dynwind.h"
+#include "libguile/deprecation.h"
+
+#include "libguile/validate.h"
+#include "libguile/async.h"
+
+#ifdef HAVE_STRING_H
+#include <string.h>
+#endif
+#ifdef HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+
+#include <full-write.h>
+
+\f
+/* {Asynchronous Events}
+ *
+ * There are two kinds of asyncs: system asyncs and user asyncs. The
+ * two kinds have some concepts in commen but work slightly
+ * differently and are not interchangeable.
+ *
+ * System asyncs are used to run arbitrary code at the next safe point
+ * in a specified thread. You can use them to trigger execution of
+ * Scheme code from signal handlers or to interrupt a thread, for
+ * example.
+ *
+ * Each thread has a list of 'activated asyncs', which is a normal
+ * Scheme list of procedures with zero arguments. When a thread
+ * executes a SCM_ASYNC_TICK statement (which is included in
+ * SCM_TICK), it will call all procedures on this list.
+ *
+ * Also, a thread will wake up when a procedure is added to its list
+ * of active asyncs and call them. After that, it will go to sleep
+ * again. (Not implemented yet.)
+ *
+ *
+ * User asyncs are a little data structure that consists of a
+ * procedure of zero arguments and a mark. There are functions for
+ * setting the mark of a user async and for calling all procedures of
+ * marked asyncs in a given list. Nothing you couldn't quickly
+ * implement yourself.
+ */
+
+
+\f
+
+/* User asyncs. */
+
+static scm_t_bits tc16_async;
+
+/* cmm: this has SCM_ prefix because SCM_MAKE_VALIDATE expects it.
+ this is ugly. */
+#define SCM_ASYNCP(X) SCM_TYP16_PREDICATE (tc16_async, X)
+#define VALIDATE_ASYNC(pos, a) SCM_MAKE_VALIDATE_MSG(pos, a, ASYNCP, "user async")
+
+#define ASYNC_GOT_IT(X) (SCM_SMOB_FLAGS (X))
+#define SET_ASYNC_GOT_IT(X, V) (SCM_SET_SMOB_FLAGS ((X), ((V))))
+#define ASYNC_THUNK(X) SCM_SMOB_OBJECT_1 (X)
+
+
+SCM_DEFINE (scm_async, "async", 1, 0, 0,
+ (SCM thunk),
+ "Create a new async for the procedure @var{thunk}.")
+#define FUNC_NAME s_scm_async
+{
+ SCM_RETURN_NEWSMOB (tc16_async, SCM_UNPACK (thunk));
+}
+#undef FUNC_NAME
+
+SCM_DEFINE (scm_async_mark, "async-mark", 1, 0, 0,
+ (SCM a),
+ "Mark the async @var{a} for future execution.")
+#define FUNC_NAME s_scm_async_mark
+{
+ VALIDATE_ASYNC (1, a);
+ SET_ASYNC_GOT_IT (a, 1);
+ return SCM_UNSPECIFIED;
+}
+#undef FUNC_NAME
+
+SCM_DEFINE (scm_run_asyncs, "run-asyncs", 1, 0, 0,
+ (SCM list_of_a),
+ "Execute all thunks from the asyncs of the list @var{list_of_a}.")
+#define FUNC_NAME s_scm_run_asyncs
+{
+ while (! SCM_NULL_OR_NIL_P (list_of_a))
+ {
+ SCM a;
+ SCM_VALIDATE_CONS (1, list_of_a);
+ a = SCM_CAR (list_of_a);
+ VALIDATE_ASYNC (SCM_ARG1, a);
+ if (ASYNC_GOT_IT (a))
+ {
+ SET_ASYNC_GOT_IT (a, 0);
+ scm_call_0 (ASYNC_THUNK (a));
+ }
+ list_of_a = SCM_CDR (list_of_a);
+ }
+ return SCM_BOOL_T;
+}
+#undef FUNC_NAME
+
+\f
+
+static scm_i_pthread_mutex_t async_mutex = SCM_I_PTHREAD_MUTEX_INITIALIZER;
+
+/* System asyncs. */
+
+void
+scm_async_tick (void)
+{
+ scm_i_thread *t = SCM_I_CURRENT_THREAD;
+ SCM asyncs;
+
+ /* Reset pending_asyncs even when asyncs are blocked and not really
+ executed since this will avoid future futile calls to this
+ function. When asyncs are unblocked again, this function is
+ invoked even when pending_asyncs is zero.
+ */
+
+ scm_i_scm_pthread_mutex_lock (&async_mutex);
+ t->pending_asyncs = 0;
+ if (t->block_asyncs == 0)
+ {
+ asyncs = t->active_asyncs;
+ t->active_asyncs = SCM_EOL;
+ }
+ else
+ asyncs = SCM_EOL;
+ scm_i_pthread_mutex_unlock (&async_mutex);
+
+ while (scm_is_pair (asyncs))
+ {
+ SCM next = SCM_CDR (asyncs);
+ SCM_SETCDR (asyncs, SCM_BOOL_F);
+ scm_call_0 (SCM_CAR (asyncs));
+ asyncs = next;
+ }
+}
+
+void
+scm_i_queue_async_cell (SCM c, scm_i_thread *t)
+{
+ SCM sleep_object;
+ scm_i_pthread_mutex_t *sleep_mutex;
+ int sleep_fd;
+ SCM p;
+
+ scm_i_scm_pthread_mutex_lock (&async_mutex);
+ p = t->active_asyncs;
+ SCM_SETCDR (c, SCM_EOL);
+ if (!scm_is_pair (p))
+ t->active_asyncs = c;
+ else
+ {
+ SCM pp;
+ while (scm_is_pair (pp = SCM_CDR (p)))
+ {
+ if (scm_is_eq (SCM_CAR (p), SCM_CAR (c)))
+ {
+ scm_i_pthread_mutex_unlock (&async_mutex);
+ return;
+ }
+ p = pp;
+ }
+ SCM_SETCDR (p, c);
+ }
+ t->pending_asyncs = 1;
+ sleep_object = t->sleep_object;
+ sleep_mutex = t->sleep_mutex;
+ sleep_fd = t->sleep_fd;
+ scm_i_pthread_mutex_unlock (&async_mutex);
+
+ if (sleep_mutex)
+ {
+ /* By now, the thread T might be out of its sleep already, or
+ might even be in the next, unrelated sleep. Interrupting it
+ anyway does no harm, however.
+
+ The important thing to prevent here is to signal sleep_cond
+ before T waits on it. This can not happen since T has
+ sleep_mutex locked while setting t->sleep_mutex and will only
+ unlock it again while waiting on sleep_cond.
+ */
+ scm_i_scm_pthread_mutex_lock (sleep_mutex);
+ scm_i_pthread_cond_signal (&t->sleep_cond);
+ scm_i_pthread_mutex_unlock (sleep_mutex);
+ }
+
+ if (sleep_fd >= 0)
+ {
+ char dummy = 0;
+
+ /* Likewise, T might already been done with sleeping here, but
+ interrupting it once too often does no harm. T might also
+ not yet have started sleeping, but this is no problem either
+ since the data written to a pipe will not be lost, unlike a
+ condition variable signal. */
+ full_write (sleep_fd, &dummy, 1);
+ }
+
+ /* This is needed to protect sleep_mutex.
+ */
+ scm_remember_upto_here_1 (sleep_object);
+}
+
+int
+scm_i_setup_sleep (scm_i_thread *t,
+ SCM sleep_object, scm_i_pthread_mutex_t *sleep_mutex,
+ int sleep_fd)
+{
+ int pending;
+
+ scm_i_scm_pthread_mutex_lock (&async_mutex);
+ pending = t->pending_asyncs;
+ if (!pending)
+ {
+ t->sleep_object = sleep_object;
+ t->sleep_mutex = sleep_mutex;
+ t->sleep_fd = sleep_fd;
+ }
+ scm_i_pthread_mutex_unlock (&async_mutex);
+ return pending;
+}
+
+void
+scm_i_reset_sleep (scm_i_thread *t)
+{
+ scm_i_scm_pthread_mutex_lock (&async_mutex);
+ t->sleep_object = SCM_BOOL_F;
+ t->sleep_mutex = NULL;
+ t->sleep_fd = -1;
+ scm_i_pthread_mutex_unlock (&async_mutex);
+}
+
+SCM_DEFINE (scm_system_async_mark_for_thread, "system-async-mark", 1, 1, 0,
+ (SCM proc, SCM thread),
+ "Mark @var{proc} (a procedure with zero arguments) for future execution\n"
+ "in @var{thread}. If @var{proc} has already been marked for\n"
+ "@var{thread} but has not been executed yet, this call has no effect.\n"
+ "If @var{thread} is omitted, the thread that called\n"
+ "@code{system-async-mark} is used.\n\n"
+ "This procedure is not safe to be called from C signal handlers. Use\n"
+ "@code{scm_sigaction} or @code{scm_sigaction_for_thread} to install\n"
+ "signal handlers.")
+#define FUNC_NAME s_scm_system_async_mark_for_thread
+{
+ /* The current thread might not have a handle yet. This can happen
+ when the GC runs immediately before allocating the handle. At
+ the end of that GC, a system async might be marked. Thus, we can
+ not use scm_current_thread here.
+ */
+
+ scm_i_thread *t;
+
+ if (SCM_UNBNDP (thread))
+ t = SCM_I_CURRENT_THREAD;
+ else
+ {
+ SCM_VALIDATE_THREAD (2, thread);
+ if (scm_c_thread_exited_p (thread))
+ SCM_MISC_ERROR ("thread has already exited", SCM_EOL);
+ t = SCM_I_THREAD_DATA (thread);
+ }
+ scm_i_queue_async_cell (scm_cons (proc, SCM_BOOL_F), t);
+ return SCM_UNSPECIFIED;
+}
+#undef FUNC_NAME
+
+SCM
+scm_system_async_mark (SCM proc)
+#define FUNC_NAME s_scm_system_async_mark_for_thread
+{
+ return scm_system_async_mark_for_thread (proc, SCM_UNDEFINED);
+}
+#undef FUNC_NAME
+
+\f
+
+
+SCM_DEFINE (scm_noop, "noop", 0, 0, 1,
+ (SCM args),
+ "Do nothing. When called without arguments, return @code{#f},\n"
+ "otherwise return the first argument.")
+#define FUNC_NAME s_scm_noop
+{
+ SCM_VALIDATE_REST_ARGUMENT (args);
+ return (SCM_NULL_OR_NIL_P (args) ? SCM_BOOL_F : SCM_CAR (args));
+}
+#undef FUNC_NAME
+
+
+\f
+
+static void
+increase_block (void *data)
+{
+ scm_i_thread *t = data;
+ t->block_asyncs++;
+}
+
+static void
+decrease_block (void *data)
+{
+ scm_i_thread *t = data;
+ if (--t->block_asyncs == 0)
+ scm_async_tick ();
+}
+
+void
+scm_dynwind_block_asyncs (void)
+{
+ scm_i_thread *t = SCM_I_CURRENT_THREAD;
+ scm_dynwind_rewind_handler (increase_block, t, SCM_F_WIND_EXPLICITLY);
+ scm_dynwind_unwind_handler (decrease_block, t, SCM_F_WIND_EXPLICITLY);
+}
+
+void
+scm_dynwind_unblock_asyncs (void)
+{
+ scm_i_thread *t = SCM_I_CURRENT_THREAD;
+ if (t->block_asyncs == 0)
+ scm_misc_error ("scm_with_unblocked_asyncs",
+ "asyncs already unblocked", SCM_EOL);
+ scm_dynwind_rewind_handler (decrease_block, t, SCM_F_WIND_EXPLICITLY);
+ scm_dynwind_unwind_handler (increase_block, t, SCM_F_WIND_EXPLICITLY);
+}
+
+SCM_DEFINE (scm_call_with_blocked_asyncs, "call-with-blocked-asyncs", 1, 0, 0,
+ (SCM proc),
+ "Call @var{proc} with no arguments and block the execution\n"
+ "of system asyncs by one level for the current thread while\n"
+ "it is running. Return the value returned by @var{proc}.\n")
+#define FUNC_NAME s_scm_call_with_blocked_asyncs
+{
+ SCM ans;
+
+ scm_dynwind_begin (SCM_F_DYNWIND_REWINDABLE);
+ scm_dynwind_block_asyncs ();
+ ans = scm_call_0 (proc);
+ scm_dynwind_end ();
+
+ return ans;
+}
+#undef FUNC_NAME
+
+void *
+scm_c_call_with_blocked_asyncs (void *(*proc) (void *data), void *data)
+{
+ void* ans;
+
+ scm_dynwind_begin (SCM_F_DYNWIND_REWINDABLE);
+ scm_dynwind_block_asyncs ();
+ ans = proc (data);
+ scm_dynwind_end ();
+
+ return ans;
+}
+
+
+SCM_DEFINE (scm_call_with_unblocked_asyncs, "call-with-unblocked-asyncs", 1, 0, 0,
+ (SCM proc),
+ "Call @var{proc} with no arguments and unblock the execution\n"
+ "of system asyncs by one level for the current thread while\n"
+ "it is running. Return the value returned by @var{proc}.\n")
+#define FUNC_NAME s_scm_call_with_unblocked_asyncs
+{
+ SCM ans;
+
+ if (SCM_I_CURRENT_THREAD->block_asyncs == 0)
+ SCM_MISC_ERROR ("asyncs already unblocked", SCM_EOL);
+
+ scm_dynwind_begin (SCM_F_DYNWIND_REWINDABLE);
+ scm_dynwind_unblock_asyncs ();
+ ans = scm_call_0 (proc);
+ scm_dynwind_end ();
+
+ return ans;
+}
+#undef FUNC_NAME
+
+void *
+scm_c_call_with_unblocked_asyncs (void *(*proc) (void *data), void *data)
+{
+ void* ans;
+
+ if (SCM_I_CURRENT_THREAD->block_asyncs == 0)
+ scm_misc_error ("scm_c_call_with_unblocked_asyncs",
+ "asyncs already unblocked", SCM_EOL);
+
+ scm_dynwind_begin (SCM_F_DYNWIND_REWINDABLE);
+ scm_dynwind_unblock_asyncs ();
+ ans = proc (data);
+ scm_dynwind_end ();
+
+ return ans;
+}
+
+\f
+/* These are function variants of the same-named macros (uppercase) for use
+ outside of libguile. This is so that `SCM_I_CURRENT_THREAD', which may
+ reside in TLS, is not accessed from outside of libguile. It thus allows
+ libguile to be built with the "local-dynamic" TLS model. */
+
+void
+scm_critical_section_start (void)
+{
+ SCM_CRITICAL_SECTION_START;
+}
+
+void
+scm_critical_section_end (void)
+{
+ SCM_CRITICAL_SECTION_END;
+}
+
+\f
+
+void
+scm_init_async ()
+{
+ tc16_async = scm_make_smob_type ("async", 0);
+
+#include "libguile/async.x"
+}
+
+/*
+ Local Variables:
+ c-file-style: "gnu"
+ End:
+*/