default: esd is obsolete, hence don't load it anymore by default
[pulseaudio-mirror.git] / src / pulsecore / once.c
blob4e509e0cca0fc71af5e85b990bad87ada5178e8b
1 /***
2 This file is part of PulseAudio.
4 Copyright 2006 Lennart Poettering
6 PulseAudio is free software; you can redistribute it and/or modify
7 it under the terms of the GNU Lesser General Public License as published
8 by the Free Software Foundation; either version 2.1 of the License,
9 or (at your option) any later version.
11 PulseAudio is distributed in the hope that it will be useful, but
12 WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 General Public License for more details.
16 You should have received a copy of the GNU Lesser General Public License
17 along with PulseAudio; if not, write to the Free Software
18 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
19 USA.
20 ***/
22 #ifdef HAVE_CONFIG_H
23 #include <config.h>
24 #endif
26 #include <pulsecore/macro.h>
27 #include <pulsecore/mutex.h>
29 #include "once.h"
31 pa_bool_t pa_once_begin(pa_once *control) {
32 pa_assert(control);
34 if (pa_atomic_load(&control->done))
35 return FALSE;
37 pa_atomic_inc(&control->ref);
39 /* Caveat: We have to make sure that the once func has completed
40 * before returning, even if the once func is not actually
41 * executed by us. Hence the awkward locking. */
43 for (;;) {
44 pa_mutex *m;
46 if ((m = pa_atomic_ptr_load(&control->mutex))) {
48 /* The mutex is stored in locked state, hence let's just
49 * wait until it is unlocked */
50 pa_mutex_lock(m);
52 pa_assert(pa_atomic_load(&control->done));
54 pa_once_end(control);
55 return FALSE;
58 pa_assert_se(m = pa_mutex_new(FALSE, FALSE));
59 pa_mutex_lock(m);
61 if (pa_atomic_ptr_cmpxchg(&control->mutex, NULL, m))
62 return TRUE;
64 pa_mutex_unlock(m);
65 pa_mutex_free(m);
69 void pa_once_end(pa_once *control) {
70 pa_mutex *m;
72 pa_assert(control);
74 pa_atomic_store(&control->done, 1);
76 pa_assert_se(m = pa_atomic_ptr_load(&control->mutex));
77 pa_mutex_unlock(m);
79 if (pa_atomic_dec(&control->ref) <= 1) {
80 pa_assert_se(pa_atomic_ptr_cmpxchg(&control->mutex, m, NULL));
81 pa_mutex_free(m);
85 /* Not reentrant -- how could it be? */
86 void pa_run_once(pa_once *control, pa_once_func_t func) {
87 pa_assert(control);
88 pa_assert(func);
90 if (pa_once_begin(control)) {
91 func();
92 pa_once_end(control);