--- /dev/null
+/* Copyright (C) 1995,1996,1997,1998,2000,2001, 2002, 2004, 2006, 2008 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+
+\f
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#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/lang.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
+
+\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_CELL_WORD_0 (X) >> 16)
+#define SET_ASYNC_GOT_IT(X, V) (SCM_SET_CELL_WORD_0 ((X), SCM_TYP16 (X) | ((V) << 16)))
+#define ASYNC_THUNK(X) SCM_CELL_OBJECT_1 (X)
+
+static SCM
+async_gc_mark (SCM obj)
+{
+ return ASYNC_THUNK (obj);
+}
+
+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_click ()
+{
+ 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_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;
+ }
+}
+
+#if (SCM_ENABLE_DEPRECATED == 1)
+
+SCM_DEFINE (scm_system_async, "system-async", 1, 0, 0,
+ (SCM thunk),
+ "This function is deprecated. You can use @var{thunk} directly\n"
+ "instead of explicitly creating an async object.\n")
+#define FUNC_NAME s_scm_system_async
+{
+ scm_c_issue_deprecation_warning
+ ("'system-async' is deprecated. "
+ "Use the procedure directly with 'system-async-mark'.");
+ return thunk;
+}
+#undef FUNC_NAME
+
+#endif /* SCM_ENABLE_DEPRECATED == 1 */
+
+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_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)
+ {
+ size_t count;
+ 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. */
+ count = 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_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_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
+
+#if (SCM_ENABLE_DEPRECATED == 1)
+
+SCM_DEFINE (scm_unmask_signals, "unmask-signals", 0, 0, 0,
+ (),
+ "Unmask signals. The returned value is not specified.")
+#define FUNC_NAME s_scm_unmask_signals
+{
+ scm_i_thread *t = SCM_I_CURRENT_THREAD;
+
+ scm_c_issue_deprecation_warning
+ ("'unmask-signals' is deprecated. "
+ "Use 'call-with-blocked-asyncs' instead.");
+
+ if (t->block_asyncs == 0)
+ SCM_MISC_ERROR ("signals already unmasked", SCM_EOL);
+ t->block_asyncs = 0;
+ scm_async_click ();
+ return SCM_UNSPECIFIED;
+}
+#undef FUNC_NAME
+
+
+SCM_DEFINE (scm_mask_signals, "mask-signals", 0, 0, 0,
+ (),
+ "Mask signals. The returned value is not specified.")
+#define FUNC_NAME s_scm_mask_signals
+{
+ scm_i_thread *t = SCM_I_CURRENT_THREAD;
+
+ scm_c_issue_deprecation_warning
+ ("'mask-signals' is deprecated. Use 'call-with-blocked-asyncs' instead.");
+
+ if (t->block_asyncs > 0)
+ SCM_MISC_ERROR ("signals already masked", SCM_EOL);
+ t->block_asyncs = 1;
+ return SCM_UNSPECIFIED;
+}
+#undef FUNC_NAME
+
+#endif /* SCM_ENABLE_DEPRECATED == 1 */
+
+static void
+increase_block (void *data)
+{
+ ((scm_i_thread *)data)->block_asyncs++;
+}
+
+static void
+decrease_block (void *data)
+{
+ if (--((scm_i_thread *)data)->block_asyncs == 0)
+ scm_async_click ();
+}
+
+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
+{
+ return scm_internal_dynamic_wind (increase_block,
+ (scm_t_inner) scm_call_0,
+ decrease_block,
+ (void *)proc,
+ SCM_I_CURRENT_THREAD);
+}
+#undef FUNC_NAME
+
+void *
+scm_c_call_with_blocked_asyncs (void *(*proc) (void *data), void *data)
+{
+ return (void *)scm_internal_dynamic_wind (increase_block,
+ (scm_t_inner) proc,
+ decrease_block,
+ data,
+ SCM_I_CURRENT_THREAD);
+}
+
+
+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
+{
+ if (SCM_I_CURRENT_THREAD->block_asyncs == 0)
+ SCM_MISC_ERROR ("asyncs already unblocked", SCM_EOL);
+ return scm_internal_dynamic_wind (decrease_block,
+ (scm_t_inner) scm_call_0,
+ increase_block,
+ (void *)proc,
+ SCM_I_CURRENT_THREAD);
+}
+#undef FUNC_NAME
+
+void *
+scm_c_call_with_unblocked_asyncs (void *(*proc) (void *data), void *data)
+{
+ if (SCM_I_CURRENT_THREAD->block_asyncs == 0)
+ scm_misc_error ("scm_c_call_with_unblocked_asyncs",
+ "asyncs already unblocked", SCM_EOL);
+ return (void *)scm_internal_dynamic_wind (decrease_block,
+ (scm_t_inner) proc,
+ increase_block,
+ data,
+ SCM_I_CURRENT_THREAD);
+}
+
+void
+scm_dynwind_block_asyncs ()
+{
+ 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 ()
+{
+ 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);
+}
+
+
+\f
+
+void
+scm_init_async ()
+{
+ scm_asyncs = SCM_EOL;
+ tc16_async = scm_make_smob_type ("async", 0);
+ scm_set_smob_mark (tc16_async, async_gc_mark);
+
+#include "libguile/async.x"
+}
+
+/*
+ Local Variables:
+ c-file-style: "gnu"
+ End:
+*/
projects / lilypond.git / blobdiff