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code.delx.au - pulseaudio/blob - src/pulsecore/fdsem.c
4 This file is part of PulseAudio.
6 Copyright 2006 Lennart Poettering
8 PulseAudio is free software; you can redistribute it and/or modify
9 it under the terms of the GNU Lesser General Public License as
10 published by the Free Software Foundation; either version 2.1 of the
11 License, or (at your option) any later version.
13 PulseAudio is distributed in the hope that it will be useful, but
14 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 PulseAudio; if not, write to the Free Software
20 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
31 #include <pulsecore/atomic.h>
32 #include <pulsecore/log.h>
33 #include <pulsecore/thread.h>
34 #include <pulsecore/macro.h>
35 #include <pulsecore/core-util.h>
36 #include <pulse/xmalloc.h>
43 pa_atomic_t signalled
;
47 pa_fdsem
*pa_fdsem_new(void) {
50 f
= pa_xnew(pa_fdsem
, 1);
52 if (pipe(f
->fds
) < 0) {
57 pa_fd_set_cloexec(f
->fds
[0], 1);
58 pa_fd_set_cloexec(f
->fds
[1], 1);
60 pa_atomic_store(&f
->waiting
, 0);
61 pa_atomic_store(&f
->signalled
, 0);
62 pa_atomic_store(&f
->in_pipe
, 0);
67 void pa_fdsem_free(pa_fdsem
*f
) {
76 static void flush(pa_fdsem
*f
) {
80 if (pa_atomic_load(&f
->in_pipe
) <= 0)
86 if ((r
= read(f
->fds
[0], &x
, sizeof(x
))) <= 0) {
87 pa_assert(r
< 0 && errno
== EINTR
);
91 } while (pa_atomic_sub(&f
->in_pipe
, r
) > r
);
94 void pa_fdsem_post(pa_fdsem
*f
) {
97 if (pa_atomic_cmpxchg(&f
->signalled
, 0, 1)) {
99 if (pa_atomic_load(&f
->waiting
)) {
103 pa_atomic_inc(&f
->in_pipe
);
107 if ((r
= write(f
->fds
[1], &x
, 1)) != 1) {
108 pa_assert(r
< 0 && errno
== EINTR
);
118 void pa_fdsem_wait(pa_fdsem
*f
) {
123 if (pa_atomic_cmpxchg(&f
->signalled
, 1, 0))
126 pa_atomic_inc(&f
->waiting
);
128 while (!pa_atomic_cmpxchg(&f
->signalled
, 1, 0)) {
132 if ((r
= read(f
->fds
[0], &x
, sizeof(x
))) <= 0) {
133 pa_assert(r
< 0 && errno
== EINTR
);
137 pa_atomic_sub(&f
->in_pipe
, r
);
140 pa_atomic_dec(&f
->waiting
);
143 int pa_fdsem_try(pa_fdsem
*f
) {
148 if (pa_atomic_cmpxchg(&f
->signalled
, 1, 0))
155 int pa_fdsem_get(pa_fdsem
*f
) {
161 int pa_fdsem_before_poll(pa_fdsem
*f
) {
166 if (pa_atomic_cmpxchg(&f
->signalled
, 1, 0))
169 pa_atomic_inc(&f
->waiting
);
171 if (pa_atomic_cmpxchg(&f
->signalled
, 1, 0)) {
172 pa_assert_se(pa_atomic_dec(&f
->waiting
) >= 1);
178 int pa_fdsem_after_poll(pa_fdsem
*f
) {
181 pa_assert_se(pa_atomic_dec(&f
->waiting
) >= 1);
185 if (pa_atomic_cmpxchg(&f
->signalled
, 1, 0))