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
26 #include <pulsecore/macro.h>
27 #include <pulsecore/mutex.h>
31 pa_bool_t pa_once_begin(pa_once *control) {
36 if (pa_atomic_load(&control->done))
39 pa_atomic_inc(&control->ref);
41 /* Caveat: We have to make sure that the once func has completed
42 * before returning, even if the once func is not actually
43 * executed by us. Hence the awkward locking. */
47 if ((m = pa_atomic_ptr_load(&control->mutex))) {
49 /* The mutex is stored in locked state, hence let's just
50 * wait until it is unlocked */
53 pa_assert(pa_atomic_load(&control->done));
59 pa_assert_se(m = pa_mutex_new(FALSE, FALSE));
62 if (pa_atomic_ptr_cmpxchg(&control->mutex, NULL, m))
70 void pa_once_end(pa_once *control) {
75 pa_atomic_store(&control->done, 1);
77 pa_assert_se(m = pa_atomic_ptr_load(&control->mutex));
80 if (pa_atomic_dec(&control->ref) <= 1) {
81 pa_assert_se(pa_atomic_ptr_cmpxchg(&control->mutex, m, NULL));
86 /* Not reentrant -- how could it be? */
87 void pa_run_once(pa_once *control, pa_once_func_t func) {
91 if (pa_once_begin(control)) {