code.delx.au - pulseaudio/blob - src/pulsecore/mutex-posix.c

   1 /***
   2   This file is part of PulseAudio.
   3
   4   Copyright 2006 Lennart Poettering
   5
   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.
  10
  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.
  15
  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 ***/
  21
  22 #ifdef HAVE_CONFIG_H
  23 #include <config.h>
  24 #endif
  25
  26 #include <pthread.h>
  27 #include <errno.h>
  28
  29 #include <pulse/xmalloc.h>
  30 #include <pulsecore/macro.h>
  31
  32 #include "mutex.h"
  33
  34 struct pa_mutex {
  35     pthread_mutex_t mutex;
  36 };
  37
  38 struct pa_cond {
  39     pthread_cond_t cond;
  40 };
  41
  42 pa_mutex* pa_mutex_new(bool recursive, bool inherit_priority) {
  43     pa_mutex *m;
  44     pthread_mutexattr_t attr;
  45 #ifdef HAVE_PTHREAD_PRIO_INHERIT
  46     int r;
  47 #endif
  48
  49     pa_assert_se(pthread_mutexattr_init(&attr) == 0);
  50
  51     if (recursive)
  52         pa_assert_se(pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE) == 0);
  53
  54 #ifdef HAVE_PTHREAD_PRIO_INHERIT
  55     if (inherit_priority) {
  56         r = pthread_mutexattr_setprotocol(&attr, PTHREAD_PRIO_INHERIT);
  57         pa_assert(r == 0 || r == ENOTSUP);
  58     }
  59 #endif
  60
  61     m = pa_xnew(pa_mutex, 1);
  62
  63 #ifndef HAVE_PTHREAD_PRIO_INHERIT
  64     pa_assert_se(pthread_mutex_init(&m->mutex, &attr) == 0);
  65
  66 #else
  67     if ((r = pthread_mutex_init(&m->mutex, &attr))) {
  68
  69         /* If this failed, then this was probably due to non-available
  70          * priority inheritance. In which case we fall back to normal
  71          * mutexes. */
  72         pa_assert(r == ENOTSUP && inherit_priority);
  73
  74         pa_assert_se(pthread_mutexattr_setprotocol(&attr, PTHREAD_PRIO_NONE) == 0);
  75         pa_assert_se(pthread_mutex_init(&m->mutex, &attr) == 0);
  76     }
  77 #endif
  78
  79     return m;
  80 }
  81
  82 void pa_mutex_free(pa_mutex *m) {
  83     pa_assert(m);
  84
  85     pa_assert_se(pthread_mutex_destroy(&m->mutex) == 0);
  86     pa_xfree(m);
  87 }
  88
  89 void pa_mutex_lock(pa_mutex *m) {
  90     pa_assert(m);
  91
  92     pa_assert_se(pthread_mutex_lock(&m->mutex) == 0);
  93 }
  94
  95 bool pa_mutex_try_lock(pa_mutex *m) {
  96     int r;
  97     pa_assert(m);
  98
  99     if ((r = pthread_mutex_trylock(&m->mutex)) != 0) {
 100         pa_assert(r == EBUSY);
 101         return false;
 102     }
 103
 104     return true;
 105 }
 106
 107 void pa_mutex_unlock(pa_mutex *m) {
 108     pa_assert(m);
 109
 110     pa_assert_se(pthread_mutex_unlock(&m->mutex) == 0);
 111 }
 112
 113 pa_cond *pa_cond_new(void) {
 114     pa_cond *c;
 115
 116     c = pa_xnew(pa_cond, 1);
 117     pa_assert_se(pthread_cond_init(&c->cond, NULL) == 0);
 118     return c;
 119 }
 120
 121 void pa_cond_free(pa_cond *c) {
 122     pa_assert(c);
 123
 124     pa_assert_se(pthread_cond_destroy(&c->cond) == 0);
 125     pa_xfree(c);
 126 }
 127
 128 void pa_cond_signal(pa_cond *c, int broadcast) {
 129     pa_assert(c);
 130
 131     if (broadcast)
 132         pa_assert_se(pthread_cond_broadcast(&c->cond) == 0);
 133     else
 134         pa_assert_se(pthread_cond_signal(&c->cond) == 0);
 135 }
 136
 137 int pa_cond_wait(pa_cond *c, pa_mutex *m) {
 138     pa_assert(c);
 139     pa_assert(m);
 140
 141     return pthread_cond_wait(&c->cond, &m->mutex);
 142 }
 143
 144 pa_mutex* pa_static_mutex_get(pa_static_mutex *s, bool recursive, bool inherit_priority) {
 145     pa_mutex *m;
 146
 147     pa_assert(s);
 148
 149     /* First, check if already initialized and short cut */
 150     if ((m = pa_atomic_ptr_load(&s->ptr)))
 151         return m;
 152
 153     /* OK, not initialized, so let's allocate, and fill in */
 154     m = pa_mutex_new(recursive, inherit_priority);
 155     if ((pa_atomic_ptr_cmpxchg(&s->ptr, NULL, m)))
 156         return m;
 157
 158     pa_mutex_free(m);
 159
 160     /* Him, filling in failed, so someone else must have filled in
 161      * already */
 162     pa_assert_se(m = pa_atomic_ptr_load(&s->ptr));
 163     return m;
 164 }