1 /* GLIB - Library of useful routines for C programming
2 * Copyright (C) 1995-1997 Peter Mattis, Spencer Kimball and Josh MacDonald
4 * gthread.c: MT safety related functions
5 * Copyright 1998 Sebastian Wilhelmi; University of Karlsruhe
8 * This library is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2 of the License, or (at your option) any later version.
13 * This library is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with this library; if not, write to the
20 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
21 * Boston, MA 02111-1307, USA.
25 * Modified by the GLib Team and others 1997-2000. See the AUTHORS
26 * file for a list of people on the GLib Team. See the ChangeLog
27 * files for a list of changes. These files are distributed with
28 * GLib at ftp://ftp.gtk.org/pub/gtk/.
45 #include "gthreadinit.h"
47 #if GLIB_SIZEOF_SYSTEM_THREAD == SIZEOF_VOID_P
48 # define g_system_thread_equal_simple(thread1, thread2) \
49 ((thread1).dummy_pointer == (thread2).dummy_pointer)
50 # define g_system_thread_assign(dest, src) \
51 ((dest).dummy_pointer = (src).dummy_pointer)
52 #else /* GLIB_SIZEOF_SYSTEM_THREAD != SIZEOF_VOID_P */
53 # define g_system_thread_equal_simple(thread1, thread2) \
54 (memcmp (&(thread1), &(thread2), GLIB_SIZEOF_SYSTEM_THREAD) == 0)
55 # define g_system_thread_assign(dest, src) \
56 (memcpy (&(dest), &(src), GLIB_SIZEOF_SYSTEM_THREAD))
57 #endif /* GLIB_SIZEOF_SYSTEM_THREAD == SIZEOF_VOID_P */
59 #define g_system_thread_equal(thread1, thread2) \
60 (g_thread_functions_for_glib_use.thread_equal ? \
61 g_thread_functions_for_glib_use.thread_equal (&(thread1), &(thread2)) :\
62 g_system_thread_equal_simple((thread1), (thread2)))
65 g_thread_error_quark (void)
69 quark = g_quark_from_static_string ("g_thread_error");
73 /* Keep this in sync with GRealThread in gmain.c! */
74 typedef struct _GRealThread GRealThread;
78 gpointer private_data;
80 GSystemThread system_thread;
83 typedef struct _GStaticPrivateNode GStaticPrivateNode;
84 struct _GStaticPrivateNode
87 GDestroyNotify destroy;
90 static void g_thread_cleanup (gpointer data);
91 static void g_thread_fail (void);
93 /* Global variables */
95 static GSystemThread zero_thread; /* This is initialized to all zero */
96 gboolean g_thread_use_default_impl = TRUE;
97 gboolean g_threads_got_initialized = FALSE;
99 GThreadFunctions g_thread_functions_for_glib_use = {
100 (GMutex*(*)())g_thread_fail, /* mutex_new */
101 NULL, /* mutex_lock */
102 NULL, /* mutex_trylock */
103 NULL, /* mutex_unlock */
104 NULL, /* mutex_free */
105 (GCond*(*)())g_thread_fail, /* cond_new */
106 NULL, /* cond_signal */
107 NULL, /* cond_broadcast */
108 NULL, /* cond_wait */
109 NULL, /* cond_timed_wait */
110 NULL, /* cond_free */
111 (GPrivate*(*)(GDestroyNotify))g_thread_fail, /* private_new */
112 NULL, /* private_get */
113 NULL, /* private_set */
114 (void(*)(GThreadFunc, gpointer, gulong,
115 gboolean, gboolean, GThreadPriority,
116 gpointer, GError**))g_thread_fail, /* thread_create */
117 NULL, /* thread_yield */
118 NULL, /* thread_join */
119 NULL, /* thread_exit */
120 NULL, /* thread_set_priority */
121 NULL /* thread_self */
126 static GMutex *g_once_mutex = NULL;
127 static GCond *g_once_cond = NULL;
128 static GPrivate *g_thread_specific_private = NULL;
129 static GSList *g_thread_all_threads = NULL;
130 static GSList *g_thread_free_indeces = NULL;
132 G_LOCK_DEFINE_STATIC (g_thread);
134 #ifdef G_THREADS_ENABLED
135 /* This must be called only once, before any threads are created.
136 * It will only be called from g_thread_init() in -lgthread.
139 g_thread_init_glib (void)
141 /* We let the main thread (the one that calls g_thread_init) inherit
142 * the static_private data set before calling g_thread_init
144 GRealThread* main_thread = (GRealThread*) g_thread_self ();
146 g_once_mutex = g_mutex_new ();
147 g_once_cond = g_cond_new ();
149 _g_convert_thread_init ();
150 _g_rand_thread_init ();
151 _g_main_thread_init ();
152 _g_mem_thread_init ();
153 _g_messages_thread_init ();
154 _g_atomic_thread_init ();
156 g_threads_got_initialized = TRUE;
158 g_thread_specific_private = g_private_new (g_thread_cleanup);
159 g_private_set (g_thread_specific_private, main_thread);
160 G_THREAD_UF (thread_self, (&main_thread->system_thread));
162 _g_mem_thread_private_init ();
163 _g_messages_thread_private_init ();
166 #endif /* G_THREADS_ENABLED */
169 g_once_impl (GOnce *once,
173 g_mutex_lock (g_once_mutex);
175 while (once->status == G_ONCE_STATUS_PROGRESS)
176 g_cond_wait (g_once_cond, g_once_mutex);
178 if (once->status != G_ONCE_STATUS_READY)
180 once->status = G_ONCE_STATUS_PROGRESS;
181 g_mutex_unlock (g_once_mutex);
183 once->retval = func (arg);
185 g_mutex_lock (g_once_mutex);
186 once->status = G_ONCE_STATUS_READY;
187 g_cond_broadcast (g_once_cond);
190 g_mutex_unlock (g_once_mutex);
196 g_static_mutex_init (GStaticMutex *mutex)
198 static GStaticMutex init_mutex = G_STATIC_MUTEX_INIT;
200 g_return_if_fail (mutex);
206 g_static_mutex_get_mutex_impl (GMutex** mutex)
208 if (!g_thread_supported ())
211 g_assert (g_once_mutex);
213 g_mutex_lock (g_once_mutex);
217 GMutex *new_mutex = g_mutex_new ();
219 /* The following is a memory barrier to avoid the write
220 * to *new_mutex being reordered to after writing *mutex */
221 g_mutex_lock (new_mutex);
222 g_mutex_unlock (new_mutex);
227 g_mutex_unlock (g_once_mutex);
233 g_static_mutex_free (GStaticMutex* mutex)
235 GMutex **runtime_mutex;
237 g_return_if_fail (mutex);
239 /* The runtime_mutex is the first (or only) member of GStaticMutex,
240 * see both versions (of glibconfig.h) in configure.in */
241 runtime_mutex = ((GMutex**)mutex);
244 g_mutex_free (*runtime_mutex);
246 *runtime_mutex = NULL;
250 g_static_rec_mutex_init (GStaticRecMutex *mutex)
252 static GStaticRecMutex init_mutex = G_STATIC_REC_MUTEX_INIT;
254 g_return_if_fail (mutex);
260 g_static_rec_mutex_lock (GStaticRecMutex* mutex)
264 g_return_if_fail (mutex);
266 if (!g_thread_supported ())
269 G_THREAD_UF (thread_self, (&self));
271 if (g_system_thread_equal (self, mutex->owner))
276 g_static_mutex_lock (&mutex->mutex);
277 g_system_thread_assign (mutex->owner, self);
282 g_static_rec_mutex_trylock (GStaticRecMutex* mutex)
286 g_return_val_if_fail (mutex, FALSE);
288 if (!g_thread_supported ())
291 G_THREAD_UF (thread_self, (&self));
293 if (g_system_thread_equal (self, mutex->owner))
299 if (!g_static_mutex_trylock (&mutex->mutex))
302 g_system_thread_assign (mutex->owner, self);
308 g_static_rec_mutex_unlock (GStaticRecMutex* mutex)
310 g_return_if_fail (mutex);
312 if (!g_thread_supported ())
315 if (mutex->depth > 1)
320 g_system_thread_assign (mutex->owner, zero_thread);
321 g_static_mutex_unlock (&mutex->mutex);
325 g_static_rec_mutex_lock_full (GStaticRecMutex *mutex,
329 g_return_if_fail (mutex);
331 if (!g_thread_supported ())
334 G_THREAD_UF (thread_self, (&self));
336 if (g_system_thread_equal (self, mutex->owner))
338 mutex->depth += depth;
341 g_static_mutex_lock (&mutex->mutex);
342 g_system_thread_assign (mutex->owner, self);
343 mutex->depth = depth;
347 g_static_rec_mutex_unlock_full (GStaticRecMutex *mutex)
351 g_return_val_if_fail (mutex, 0);
353 if (!g_thread_supported ())
356 depth = mutex->depth;
358 g_system_thread_assign (mutex->owner, zero_thread);
360 g_static_mutex_unlock (&mutex->mutex);
366 g_static_rec_mutex_free (GStaticRecMutex *mutex)
368 g_return_if_fail (mutex);
370 g_static_mutex_free (&mutex->mutex);
374 g_static_private_init (GStaticPrivate *private_key)
376 private_key->index = 0;
380 g_static_private_get (GStaticPrivate *private_key)
382 GRealThread *self = (GRealThread*) g_thread_self ();
385 array = self->private_data;
389 if (!private_key->index)
391 else if (private_key->index <= array->len)
392 return g_array_index (array, GStaticPrivateNode,
393 private_key->index - 1).data;
399 g_static_private_set (GStaticPrivate *private_key,
401 GDestroyNotify notify)
403 GRealThread *self = (GRealThread*) g_thread_self ();
405 static guint next_index = 0;
406 GStaticPrivateNode *node;
408 array = self->private_data;
411 array = g_array_new (FALSE, TRUE, sizeof (GStaticPrivateNode));
412 self->private_data = array;
415 if (!private_key->index)
419 if (!private_key->index)
421 if (g_thread_free_indeces)
424 GPOINTER_TO_UINT (g_thread_free_indeces->data);
425 g_thread_free_indeces =
426 g_slist_delete_link (g_thread_free_indeces,
427 g_thread_free_indeces);
430 private_key->index = ++next_index;
436 if (private_key->index > array->len)
437 g_array_set_size (array, private_key->index);
439 node = &g_array_index (array, GStaticPrivateNode, private_key->index - 1);
442 gpointer ddata = node->data;
443 GDestroyNotify ddestroy = node->destroy;
446 node->destroy = notify;
453 node->destroy = notify;
458 g_static_private_free (GStaticPrivate *private_key)
460 guint index = private_key->index;
466 private_key->index = 0;
469 list = g_thread_all_threads;
472 GRealThread *thread = list->data;
473 GArray *array = thread->private_data;
476 if (array && index <= array->len)
478 GStaticPrivateNode *node = &g_array_index (array,
481 gpointer ddata = node->data;
482 GDestroyNotify ddestroy = node->destroy;
485 node->destroy = NULL;
495 g_thread_free_indeces = g_slist_prepend (g_thread_free_indeces,
496 GUINT_TO_POINTER (index));
501 g_thread_cleanup (gpointer data)
505 GRealThread* thread = data;
506 if (thread->private_data)
508 GArray* array = thread->private_data;
511 for (i = 0; i < array->len; i++ )
513 GStaticPrivateNode *node =
514 &g_array_index (array, GStaticPrivateNode, i);
516 node->destroy (node->data);
518 g_array_free (array, TRUE);
521 /* We only free the thread structure, if it isn't joinable. If
522 it is, the structure is freed in g_thread_join */
523 if (!thread->thread.joinable)
526 g_thread_all_threads = g_slist_remove (g_thread_all_threads, data);
529 /* Just to make sure, this isn't used any more */
530 g_system_thread_assign (thread->system_thread, zero_thread);
539 g_error ("The thread system is not yet initialized.");
543 g_thread_create_proxy (gpointer data)
545 GRealThread* thread = data;
549 /* This has to happen before G_LOCK, as that might call g_thread_self */
550 g_private_set (g_thread_specific_private, data);
552 /* the lock makes sure, that thread->system_thread is written,
553 before thread->thread.func is called. See g_thread_create. */
557 thread->retval = thread->thread.func (thread->thread.data);
563 g_thread_create_full (GThreadFunc func,
568 GThreadPriority priority,
572 GError *local_error = NULL;
573 g_return_val_if_fail (func, NULL);
574 g_return_val_if_fail (priority >= G_THREAD_PRIORITY_LOW, NULL);
575 g_return_val_if_fail (priority <= G_THREAD_PRIORITY_URGENT, NULL);
577 result = g_new (GRealThread, 1);
579 result->thread.joinable = joinable;
580 result->thread.priority = priority;
581 result->thread.func = func;
582 result->thread.data = data;
583 result->private_data = NULL;
585 G_THREAD_UF (thread_create, (g_thread_create_proxy, result,
586 stack_size, joinable, bound, priority,
587 &result->system_thread, &local_error));
588 g_thread_all_threads = g_slist_prepend (g_thread_all_threads, result);
593 g_propagate_error (error, local_error);
598 return (GThread*) result;
602 g_thread_exit (gpointer retval)
604 GRealThread* real = (GRealThread*) g_thread_self ();
605 real->retval = retval;
606 G_THREAD_CF (thread_exit, (void)0, ());
610 g_thread_join (GThread* thread)
612 GRealThread* real = (GRealThread*) thread;
615 g_return_val_if_fail (thread, NULL);
616 g_return_val_if_fail (thread->joinable, NULL);
617 g_return_val_if_fail (!g_system_thread_equal (real->system_thread,
620 G_THREAD_UF (thread_join, (&real->system_thread));
622 retval = real->retval;
625 g_thread_all_threads = g_slist_remove (g_thread_all_threads, thread);
628 /* Just to make sure, this isn't used any more */
629 thread->joinable = 0;
630 g_system_thread_assign (real->system_thread, zero_thread);
632 /* the thread structure for non-joinable threads is freed upon
633 thread end. We free the memory here. This will leave a loose end,
634 if a joinable thread is not joined. */
642 g_thread_set_priority (GThread* thread,
643 GThreadPriority priority)
645 GRealThread* real = (GRealThread*) thread;
647 g_return_if_fail (thread);
648 g_return_if_fail (!g_system_thread_equal (real->system_thread, zero_thread));
649 g_return_if_fail (priority >= G_THREAD_PRIORITY_LOW);
650 g_return_if_fail (priority <= G_THREAD_PRIORITY_URGENT);
652 thread->priority = priority;
654 G_THREAD_CF (thread_set_priority, (void)0,
655 (&real->system_thread, priority));
661 GRealThread* thread = g_private_get (g_thread_specific_private);
665 /* If no thread data is available, provide and set one. This
666 can happen for the main thread and for threads, that are not
668 thread = g_new (GRealThread, 1);
669 thread->thread.joinable = FALSE; /* This is a save guess */
670 thread->thread.priority = G_THREAD_PRIORITY_NORMAL; /* This is
672 thread->thread.func = NULL;
673 thread->thread.data = NULL;
674 thread->private_data = NULL;
676 if (g_thread_supported ())
677 G_THREAD_UF (thread_self, (&thread->system_thread));
679 g_private_set (g_thread_specific_private, thread);
682 g_thread_all_threads = g_slist_prepend (g_thread_all_threads, thread);
686 return (GThread*)thread;
690 g_static_rw_lock_init (GStaticRWLock* lock)
692 static GStaticRWLock init_lock = G_STATIC_RW_LOCK_INIT;
694 g_return_if_fail (lock);
700 g_static_rw_lock_wait (GCond** cond, GStaticMutex* mutex)
703 *cond = g_cond_new ();
704 g_cond_wait (*cond, g_static_mutex_get_mutex (mutex));
708 g_static_rw_lock_signal (GStaticRWLock* lock)
710 if (lock->want_to_write && lock->write_cond)
711 g_cond_signal (lock->write_cond);
712 else if (lock->want_to_read && lock->read_cond)
713 g_cond_broadcast (lock->read_cond);
717 g_static_rw_lock_reader_lock (GStaticRWLock* lock)
719 g_return_if_fail (lock);
721 if (!g_threads_got_initialized)
724 g_static_mutex_lock (&lock->mutex);
725 lock->want_to_read++;
726 while (lock->have_writer || lock->want_to_write)
727 g_static_rw_lock_wait (&lock->read_cond, &lock->mutex);
728 lock->want_to_read--;
729 lock->read_counter++;
730 g_static_mutex_unlock (&lock->mutex);
734 g_static_rw_lock_reader_trylock (GStaticRWLock* lock)
736 gboolean ret_val = FALSE;
738 g_return_val_if_fail (lock, FALSE);
740 if (!g_threads_got_initialized)
743 g_static_mutex_lock (&lock->mutex);
744 if (!lock->have_writer && !lock->want_to_write)
746 lock->read_counter++;
749 g_static_mutex_unlock (&lock->mutex);
754 g_static_rw_lock_reader_unlock (GStaticRWLock* lock)
756 g_return_if_fail (lock);
758 if (!g_threads_got_initialized)
761 g_static_mutex_lock (&lock->mutex);
762 lock->read_counter--;
763 if (lock->read_counter == 0)
764 g_static_rw_lock_signal (lock);
765 g_static_mutex_unlock (&lock->mutex);
769 g_static_rw_lock_writer_lock (GStaticRWLock* lock)
771 g_return_if_fail (lock);
773 if (!g_threads_got_initialized)
776 g_static_mutex_lock (&lock->mutex);
777 lock->want_to_write++;
778 while (lock->have_writer || lock->read_counter)
779 g_static_rw_lock_wait (&lock->write_cond, &lock->mutex);
780 lock->want_to_write--;
781 lock->have_writer = TRUE;
782 g_static_mutex_unlock (&lock->mutex);
786 g_static_rw_lock_writer_trylock (GStaticRWLock* lock)
788 gboolean ret_val = FALSE;
790 g_return_val_if_fail (lock, FALSE);
792 if (!g_threads_got_initialized)
795 g_static_mutex_lock (&lock->mutex);
796 if (!lock->have_writer && !lock->read_counter)
798 lock->have_writer = TRUE;
801 g_static_mutex_unlock (&lock->mutex);
806 g_static_rw_lock_writer_unlock (GStaticRWLock* lock)
808 g_return_if_fail (lock);
810 if (!g_threads_got_initialized)
813 g_static_mutex_lock (&lock->mutex);
814 lock->have_writer = FALSE;
815 g_static_rw_lock_signal (lock);
816 g_static_mutex_unlock (&lock->mutex);
820 g_static_rw_lock_free (GStaticRWLock* lock)
822 g_return_if_fail (lock);
826 g_cond_free (lock->read_cond);
827 lock->read_cond = NULL;
829 if (lock->write_cond)
831 g_cond_free (lock->write_cond);
832 lock->write_cond = NULL;
834 g_static_mutex_free (&lock->mutex);