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-rw-r--r--libguile/async.c737
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diff --git a/libguile/async.c b/libguile/async.c
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+++ b/libguile/async.c
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+/* Copyright (C) 1995,1996 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, 675 Mass Ave, Cambridge, MA 02139, 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.
+ */
+
+
+#include <stdio.h>
+#include <signal.h>
+#include "_scm.h"
+
+#ifdef HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+
+
+
+/* {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.
+ *
+ */
+
+
+#define min(A,B) ((A) < (B) ? (A) : (B))
+
+
+unsigned int scm_async_clock = 20;
+static unsigned int scm_async_rate = 20;
+unsigned int scm_mask_ints = 1;
+
+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;
+
+static SCM system_signal_asyncs[SCM_NUM_SIGS];
+static SCM handler_var;
+static SCM symbol_signal;
+
+
+struct scm_async
+{
+ int got_it; /* needs to be delivered? */
+ SCM thunk; /* the handler. */
+};
+
+
+static long scm_tc16_async;
+
+#define SCM_ASYNCP(X) (scm_tc16_async == SCM_GCTYP16 (X))
+#define SCM_ASYNC(X) ((struct scm_async *)SCM_CDR (X))
+
+
+
+
+
+
+#ifdef __STDC__
+static int
+asyncs_pending (void)
+#else
+static int
+asyncs_pending ()
+#endif
+{
+ SCM pos;
+ pos = scm_asyncs;
+ while (pos != SCM_EOL)
+ {
+ SCM a;
+ struct scm_async * it;
+ a = SCM_CAR (pos);
+ it = SCM_ASYNC (a);
+ if (it->got_it)
+ return 1;
+ pos = SCM_CDR (pos);
+ }
+ return 0;
+}
+
+
+#ifdef __STDC__
+void
+scm_async_click (void)
+#else
+void
+scm_async_click ()
+#endif
+{
+ 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 (asyncs_pending ())
+ {
+ SCM_ALLOW_INTS_ONLY;
+ goto tail;
+ }
+ SCM_ALLOW_INTS;
+
+ if (owe_switch)
+ scm_switch ();
+}
+
+
+
+
+#ifdef __STDC__
+void
+scm_switch (void)
+#else
+void
+scm_switch ()
+#endif
+{}
+
+
+#ifdef __STDC__
+static void
+scm_deliver_signal (int num)
+#else
+static void
+scm_deliver_signal (num)
+ int num;
+#endif
+{
+ SCM handler;
+ handler = SCM_CDR (handler_var);
+ if (handler != SCM_BOOL_F)
+ scm_apply (handler, SCM_MAKINUM (num), scm_listofnull);
+ else
+ {
+ scm_mask_ints = 0;
+ scm_throw (symbol_signal,
+ scm_listify (SCM_MAKINUM (num), SCM_UNDEFINED));
+ }
+}
+
+
+
+
+#ifdef __STDC__
+static int
+print_async (SCM exp, SCM port, int writing)
+#else
+static int
+print_async (exp, port, writing)
+ SCM exp;
+ SCM port;
+ int writing;
+#endif
+{
+ scm_gen_puts (scm_regular_string, "#<async ", port);
+ scm_intprint(exp, 16, port);
+ scm_gen_putc('>', port);
+ return 1;
+}
+
+#ifdef __STDC__
+static SCM
+mark_async (SCM obj)
+#else
+static SCM
+mark_async (obj)
+ SCM obj;
+#endif
+{
+ struct scm_async * it;
+ if (SCM_GC8MARKP (obj))
+ return SCM_BOOL_F;
+ SCM_SETGC8MARK (obj);
+ it = SCM_ASYNC (obj);
+ return it->thunk;
+}
+
+#ifdef __STDC__
+static scm_sizet
+free_async (SCM obj)
+#else
+static scm_sizet
+free_async (SCM obj)
+ SCM obj;
+#endif
+{
+ struct scm_async * it;
+ it = SCM_ASYNC (obj);
+ scm_must_free ((char *)it);
+ return (sizeof (*it));
+}
+
+
+static scm_smobfuns async_smob =
+{
+ mark_async,
+ free_async,
+ print_async,
+ 0
+};
+
+
+
+
+SCM_PROC(s_async, "async", 1, 0, 0, scm_async);
+#ifdef __STDC__
+SCM
+scm_async (SCM thunk)
+#else
+SCM
+scm_async (thunk)
+ SCM thunk;
+#endif
+{
+ SCM it;
+ struct scm_async * async;
+
+ SCM_NEWCELL (it);
+ SCM_DEFER_INTS;
+ SCM_SETCDR (it, SCM_EOL);
+ async = (struct scm_async *)scm_must_malloc (sizeof (*async), s_async);
+ async->got_it = 0;
+ async->thunk = thunk;
+ SCM_SETCDR (it, (SCM)async);
+ SCM_SETCAR (it, (SCM)scm_tc16_async);
+ SCM_ALLOW_INTS;
+ return it;
+}
+
+SCM_PROC(s_system_async, "system-async", 1, 0, 0, scm_system_async);
+#ifdef __STDC__
+SCM
+scm_system_async (SCM thunk)
+#else
+SCM
+scm_system_async (thunk)
+ SCM thunk;
+#endif
+{
+ SCM it;
+ SCM list;
+
+ it = scm_async (thunk);
+ SCM_NEWCELL (list);
+ SCM_DEFER_INTS;
+ SCM_SETCAR (list, it);
+ SCM_SETCDR (list, scm_asyncs);
+ scm_asyncs = list;
+ SCM_ALLOW_INTS;
+ return it;
+}
+
+SCM_PROC(s_async_mark, "async-mark", 1, 0, 0, scm_async_mark);
+#ifdef __STDC__
+SCM
+scm_async_mark (SCM a)
+#else
+SCM
+scm_async_mark (a)
+ SCM a;
+#endif
+{
+ struct scm_async * it;
+ SCM_ASSERT (SCM_NIMP (a) && SCM_ASYNCP (a), a, SCM_ARG1, s_async_mark);
+ it = SCM_ASYNC (a);
+ it->got_it = 1;
+ return SCM_UNSPECIFIED;
+}
+
+
+SCM_PROC(s_system_async_mark, "system-async-mark", 1, 0, 0, scm_system_async_mark);
+#ifdef __STDC__
+SCM
+scm_system_async_mark (SCM a)
+#else
+SCM
+scm_system_async_mark (a)
+ SCM a;
+#endif
+{
+ struct scm_async * it;
+ SCM_ASSERT (SCM_NIMP (a) && SCM_ASYNCP (a), a, SCM_ARG1, s_async_mark);
+ it = SCM_ASYNC (a);
+ SCM_REDEFER_INTS;
+ it->got_it = 1;
+ scm_async_rate = 1 + scm_async_rate - scm_async_clock;
+ scm_async_clock = 1;
+ SCM_REALLOW_INTS;
+ return SCM_UNSPECIFIED;
+}
+
+
+SCM_PROC(s_run_asyncs, "run-asyncs", 1, 0, 0, scm_run_asyncs);
+#ifdef __STDC__
+SCM
+scm_run_asyncs (SCM list_of_a)
+#else
+SCM
+scm_run_asyncs (list_of_a)
+ SCM list_of_a;
+#endif
+{
+ SCM pos;
+
+ if (scm_mask_ints)
+ return SCM_BOOL_F;
+ pos = list_of_a;
+ while (pos != SCM_EOL)
+ {
+ SCM a;
+ struct scm_async * it;
+ SCM_ASSERT (SCM_NIMP (pos) && SCM_CONSP (pos), pos, SCM_ARG1, s_run_asyncs);
+ a = SCM_CAR (pos);
+ SCM_ASSERT (SCM_NIMP (a) && SCM_ASYNCP (a), a, SCM_ARG1, s_run_asyncs);
+ it = SCM_ASYNC (a);
+ scm_mask_ints = 1;
+ if (it->got_it)
+ {
+ it->got_it = 0;
+ scm_apply (it->thunk, SCM_EOL, SCM_EOL);
+ }
+ scm_mask_ints = 0;
+ pos = SCM_CDR (pos);
+ }
+ return SCM_BOOL_T;
+}
+
+
+
+
+SCM_PROC(s_noop, "noop", 0, 0, 1, scm_noop);
+#ifdef __STDC__
+SCM
+scm_noop (SCM args)
+#else
+SCM
+scm_noop (args)
+ SCM args;
+#endif
+{
+ return (SCM_NULLP (args)
+ ? SCM_BOOL_F
+ : SCM_CAR (args));
+}
+
+
+
+
+SCM_PROC(s_set_tick_rate, "set-tick-rate", 1, 0, 0, scm_set_tick_rate);
+#ifdef __STDC__
+SCM
+scm_set_tick_rate (SCM n)
+#else
+SCM
+scm_set_tick_rate (n)
+ SCM n;
+#endif
+{
+ unsigned int old_n;
+ SCM_ASSERT (SCM_INUMP (n), n, SCM_ARG1, s_set_tick_rate);
+ old_n = scm_tick_rate;
+ 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);
+}
+
+
+
+
+SCM_PROC(s_set_switch_rate, "set-switch-rate", 1, 0, 0, scm_set_switch_rate);
+#ifdef __STDC__
+SCM
+scm_set_switch_rate (SCM n)
+#else
+SCM
+scm_set_switch_rate (n)
+ SCM n;
+#endif
+{
+ unsigned int old_n;
+ SCM_ASSERT (SCM_INUMP (n), n, SCM_ARG1, s_set_switch_rate);
+ old_n = scm_switch_rate;
+ 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);
+}
+
+
+
+#ifdef __STDC__
+static SCM
+scm_sys_hup_async_thunk (void)
+#else
+static SCM
+scm_sys_hup_async_thunk ()
+#endif
+{
+ scm_deliver_signal (SCM_HUP_SIGNAL);
+ return SCM_BOOL_F;
+}
+
+#ifdef __STDC__
+static SCM
+scm_sys_int_async_thunk (void)
+#else
+static SCM
+scm_sys_int_async_thunk ()
+#endif
+{
+ scm_deliver_signal (SCM_INT_SIGNAL);
+ return SCM_BOOL_F;
+}
+
+#ifdef __STDC__
+static SCM
+scm_sys_fpe_async_thunk (void)
+#else
+static SCM
+scm_sys_fpe_async_thunk ()
+#endif
+{
+ scm_deliver_signal (SCM_FPE_SIGNAL);
+ return SCM_BOOL_F;
+}
+
+#ifdef __STDC__
+static SCM
+scm_sys_bus_async_thunk (void)
+#else
+static SCM
+scm_sys_bus_async_thunk ()
+#endif
+{
+ scm_deliver_signal (SCM_BUS_SIGNAL);
+ return SCM_BOOL_F;
+}
+
+#ifdef __STDC__
+static SCM
+scm_sys_segv_async_thunk (void)
+#else
+static SCM
+scm_sys_segv_async_thunk ()
+#endif
+{
+ scm_deliver_signal (SCM_SEGV_SIGNAL);
+ return SCM_BOOL_F;
+}
+
+#ifdef __STDC__
+static SCM
+scm_sys_alrm_async_thunk (void)
+#else
+static SCM
+scm_sys_alrm_async_thunk ()
+#endif
+{
+ scm_deliver_signal (SCM_ALRM_SIGNAL);
+ return SCM_BOOL_F;
+}
+
+#ifdef __STDC__
+static SCM
+scm_sys_gc_async_thunk (void)
+#else
+static SCM
+scm_sys_gc_async_thunk ()
+#endif
+{
+ scm_deliver_signal (SCM_GC_SIGNAL);
+ return SCM_BOOL_F;
+}
+
+#ifdef __STDC__
+static SCM
+scm_sys_tick_async_thunk (void)
+#else
+static SCM
+scm_sys_tick_async_thunk ()
+#endif
+{
+ scm_deliver_signal (SCM_TICK_SIGNAL);
+ return SCM_BOOL_F;
+}
+
+
+
+
+
+#ifdef __STDC__
+SCM
+scm_take_signal (int n)
+#else
+SCM
+scm_take_signal (n)
+ int n;
+#endif
+{
+ SCM ignored;
+ if (!scm_ints_disabled)
+ {
+ SCM_NEWCELL (ignored); /* In case we interrupted SCM_NEWCELL,
+ * throw out the possibly already allocated
+ * free cell.
+ */
+ }
+ scm_system_async_mark (system_signal_asyncs[SCM_SIG_ORD(n)]);
+ return SCM_BOOL_F;
+}
+
+
+
+SCM_PROC(s_unmask_signals, "unmask-signals", 0, 0, 0, scm_unmask_signals);
+#ifdef __STDC__
+SCM
+scm_unmask_signals (void)
+#else
+SCM
+scm_unmask_signals ()
+#endif
+{
+ scm_mask_ints = 0;
+ return SCM_UNSPECIFIED;
+}
+
+
+SCM_PROC(s_mask_signals, "mask-signals", 0, 0, 0, scm_mask_signals);
+#ifdef __STDC__
+SCM
+scm_mask_signals (void)
+#else
+SCM
+scm_mask_signals ()
+#endif
+{
+ scm_mask_ints = 1;
+ return SCM_UNSPECIFIED;
+}
+
+
+
+#ifdef __STDC__
+void
+scm_init_async (void)
+#else
+void
+scm_init_async ()
+#endif
+{
+ SCM a_thunk;
+ scm_tc16_async = scm_newsmob (&async_smob);
+ symbol_signal = SCM_CAR (scm_sysintern ("signal", strlen ("signal")));
+ scm_permanent_object (symbol_signal);
+
+ /* These are in the opposite order of delivery priortity.
+ *
+ * Error conditions are given low priority:
+ */
+ a_thunk = scm_make_gsubr ("%hup-thunk", 0, 0, 0, scm_sys_hup_async_thunk);
+ system_signal_asyncs[SCM_SIG_ORD(SCM_HUP_SIGNAL)] = scm_system_async (a_thunk);
+ a_thunk = scm_make_gsubr ("%int-thunk", 0, 0, 0, scm_sys_int_async_thunk);
+ system_signal_asyncs[SCM_SIG_ORD(SCM_INT_SIGNAL)] = scm_system_async (a_thunk);
+ a_thunk = scm_make_gsubr ("%fpe-thunk", 0, 0, 0, scm_sys_fpe_async_thunk);
+ system_signal_asyncs[SCM_SIG_ORD(SCM_FPE_SIGNAL)] = scm_system_async (a_thunk);
+ a_thunk = scm_make_gsubr ("%bus-thunk", 0, 0, 0, scm_sys_bus_async_thunk);
+ system_signal_asyncs[SCM_SIG_ORD(SCM_BUS_SIGNAL)] = scm_system_async (a_thunk);
+ a_thunk = scm_make_gsubr ("%segv-thunk", 0, 0, 0, scm_sys_segv_async_thunk);
+ system_signal_asyncs[SCM_SIG_ORD(SCM_SEGV_SIGNAL)] = scm_system_async (a_thunk);
+
+
+ a_thunk = scm_make_gsubr ("%gc-thunk", 0, 0, 0, scm_sys_gc_async_thunk);
+ system_signal_asyncs[SCM_SIG_ORD(SCM_GC_SIGNAL)] = scm_system_async (a_thunk);
+
+ /* Clock and PC driven conditions are given highest priority. */
+ a_thunk = scm_make_gsubr ("%tick-thunk", 0, 0, 0, scm_sys_tick_async_thunk);
+ system_signal_asyncs[SCM_SIG_ORD(SCM_TICK_SIGNAL)] = scm_system_async (a_thunk);
+ a_thunk = scm_make_gsubr ("%alrm-thunk", 0, 0, 0, scm_sys_alrm_async_thunk);
+ system_signal_asyncs[SCM_SIG_ORD(SCM_ALRM_SIGNAL)] = scm_system_async (a_thunk);
+
+ handler_var = scm_sysintern ("signal-handler", strlen ("signal"));
+ SCM_SETCDR (handler_var, SCM_BOOL_F);
+ scm_permanent_object (handler_var);
+#include "async.x"
+}