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(pa_bool_t recursive, pa_bool_t inherit_priority) {
  43     pa_mutex *m;
  44     pthread_mutexattr_t attr;
  45     int r;
  46
  47     pa_assert_se(pthread_mutexattr_init(&attr) == 0);
  48
  49     if (recursive)
  50         pa_assert_se(pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE) == 0);
  51
  52 #ifdef HAVE_PTHREAD_PRIO_INHERIT
  53     if (inherit_priority)
  54         pa_assert_se(pthread_mutexattr_setprotocol(&attr, PTHREAD_PRIO_INHERIT) == 0);
  55 #endif
  56
  57     m = pa_xnew(pa_mutex, 1);
  58
  59 #ifndef HAVE_PTHREAD_PRIO_INHERIT
  60     pa_assert_se(pthread_mutex_init(&m->mutex, &attr) == 0);
  61
  62 #else
  63     if ((r = pthread_mutex_init(&m->mutex, &attr))) {
  64
  65         /* If this failed, then this was probably due to non-available
  66          * priority inheritance. In which case we fall back to normal
  67          * mutexes. */
  68         pa_assert(r == ENOTSUP && inherit_priority);
  69
  70         pa_assert_se(pthread_mutexattr_setprotocol(&attr, PTHREAD_PRIO_NONE) == 0);
  71         pa_assert_se(pthread_mutex_init(&m->mutex, &attr) == 0);
  72     }
  73 #endif
  74
  75     return m;
  76 }
  77
  78 void pa_mutex_free(pa_mutex *m) {
  79     pa_assert(m);
  80
  81     pa_assert_se(pthread_mutex_destroy(&m->mutex) == 0);
  82     pa_xfree(m);
  83 }
  84
  85 void pa_mutex_lock(pa_mutex *m) {
  86     pa_assert(m);
  87
  88     pa_assert_se(pthread_mutex_lock(&m->mutex) == 0);
  89 }
  90
  91 pa_bool_t pa_mutex_try_lock(pa_mutex *m) {
  92     int r;
  93     pa_assert(m);
  94
  95     if ((r = pthread_mutex_trylock(&m->mutex)) != 0) {
  96         pa_assert(r == EBUSY);
  97         return FALSE;
  98     }
  99
 100     return TRUE;
 101 }
 102
 103 void pa_mutex_unlock(pa_mutex *m) {
 104     pa_assert(m);
 105
 106     pa_assert_se(pthread_mutex_unlock(&m->mutex) == 0);
 107 }
 108
 109 pa_cond *pa_cond_new(void) {
 110     pa_cond *c;
 111
 112     c = pa_xnew(pa_cond, 1);
 113     pa_assert_se(pthread_cond_init(&c->cond, NULL) == 0);
 114     return c;
 115 }
 116
 117 void pa_cond_free(pa_cond *c) {
 118     pa_assert(c);
 119
 120     pa_assert_se(pthread_cond_destroy(&c->cond) == 0);
 121     pa_xfree(c);
 122 }
 123
 124 void pa_cond_signal(pa_cond *c, int broadcast) {
 125     pa_assert(c);
 126
 127     if (broadcast)
 128         pa_assert_se(pthread_cond_broadcast(&c->cond) == 0);
 129     else
 130         pa_assert_se(pthread_cond_signal(&c->cond) == 0);
 131 }
 132
 133 int pa_cond_wait(pa_cond *c, pa_mutex *m) {
 134     pa_assert(c);
 135     pa_assert(m);
 136
 137     return pthread_cond_wait(&c->cond, &m->mutex);
 138 }
 139
 140 pa_mutex* pa_static_mutex_get(pa_static_mutex *s, pa_bool_t recursive, pa_bool_t inherit_priority) {
 141     pa_mutex *m;
 142
 143     pa_assert(s);
 144
 145     /* First, check if already initialized and short cut */
 146     if ((m = pa_atomic_ptr_load(&s->ptr)))
 147         return m;
 148
 149     /* OK, not initialized, so let's allocate, and fill in */
 150     m = pa_mutex_new(recursive, inherit_priority);
 151     if ((pa_atomic_ptr_cmpxchg(&s->ptr, NULL, m)))
 152         return m;
 153
 154     pa_mutex_free(m);
 155
 156     /* Him, filling in failed, so someone else must have filled in
 157      * already */
 158     pa_assert_se(m = pa_atomic_ptr_load(&s->ptr));
 159     return m;
 160 }