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

   1 /* $Id$ */
   2
   3 /***
   4   This file is part of PulseAudio.
   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 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 <assert.h>
  27 #include <pthread.h>
  28 #include <sched.h>
  29 #include <errno.h>
  30
  31 #include <pulse/xmalloc.h>
  32 #include <pulsecore/mutex.h>
  33 #include <pulsecore/once.h>
  34 #include <pulsecore/atomic.h>
  35
  36 #include "thread.h"
  37
  38 #define ASSERT_SUCCESS(x) do { \
  39     int _r = (x); \
  40     assert(_r == 0); \
  41 } while(0)
  42
  43 struct pa_thread {
  44     pthread_t id;
  45     pa_thread_func_t thread_func;
  46     void *userdata;
  47     pa_atomic_int_t running;
  48 };
  49
  50 struct pa_tls {
  51     pthread_key_t key;
  52 };
  53
  54 static pa_tls *thread_tls;
  55 static pa_once_t thread_tls_once = PA_ONCE_INIT;
  56
  57 static void tls_free_cb(void *p) {
  58     pa_thread *t = p;
  59
  60     assert(t);
  61
  62     if (!t->thread_func)
  63         /* This is a foreign thread, we need to free the struct */
  64         pa_xfree(t);
  65 }
  66
  67 static void thread_tls_once_func(void) {
  68     thread_tls = pa_tls_new(tls_free_cb);
  69     assert(thread_tls);
  70 }
  71
  72 static void* internal_thread_func(void *userdata) {
  73     pa_thread *t = userdata;
  74     assert(t);
  75
  76     t->id = pthread_self();
  77
  78     pa_once(&thread_tls_once, thread_tls_once_func);
  79
  80     pa_tls_set(thread_tls, t);
  81
  82     pa_atomic_inc(&t->running);
  83     t->thread_func(t->userdata);
  84     pa_atomic_add(&t->running, -2);
  85
  86     return NULL;
  87 }
  88
  89 pa_thread* pa_thread_new(pa_thread_func_t thread_func, void *userdata) {
  90     pa_thread *t;
  91
  92     assert(thread_func);
  93
  94     t = pa_xnew(pa_thread, 1);
  95     t->thread_func = thread_func;
  96     t->userdata = userdata;
  97     pa_atomic_store(&t->running, 0);
  98
  99     if (pthread_create(&t->id, NULL, internal_thread_func, t) < 0) {
 100         pa_xfree(t);
 101         return NULL;
 102     }
 103
 104     pa_atomic_inc(&t->running);
 105
 106     return t;
 107 }
 108
 109 int pa_thread_is_running(pa_thread *t) {
 110     assert(t);
 111
 112     if (!t->thread_func) {
 113         /* Mhmm, this is a foreign thread, t->running is not
 114          * necessarily valid. We misuse pthread_getschedparam() to
 115          * check if the thread is valid. This might not be portable. */
 116
 117         int policy;
 118         struct sched_param param;
 119
 120         return pthread_getschedparam(t->id, &policy, &param) >= 0 || errno != ESRCH;
 121     }
 122
 123     return pa_atomic_load(&t->running) > 0;
 124 }
 125
 126 void pa_thread_free(pa_thread *t) {
 127     assert(t);
 128
 129     pa_thread_join(t);
 130     pa_xfree(t);
 131 }
 132
 133 int pa_thread_join(pa_thread *t) {
 134     assert(t);
 135
 136     return pthread_join(t->id, NULL);
 137 }
 138
 139 pa_thread* pa_thread_self(void) {
 140     pa_thread *t;
 141
 142     pa_once(&thread_tls_once, thread_tls_once_func);
 143
 144     if ((t = pa_tls_get(thread_tls)))
 145         return t;
 146
 147     /* This is a foreign thread, let's create a pthread structure to
 148      * make sure that we can always return a sensible pointer */
 149
 150     t = pa_xnew(pa_thread, 1);
 151     t->id = pthread_self();
 152     t->thread_func = NULL;
 153     t->userdata = NULL;
 154     pa_atomic_store(&t->running, 2);
 155
 156     pa_tls_set(thread_tls, t);
 157
 158     return t;
 159 }
 160
 161 void* pa_thread_get_data(pa_thread *t) {
 162     assert(t);
 163
 164     return t->userdata;
 165 }
 166
 167 void pa_thread_set_data(pa_thread *t, void *userdata) {
 168     assert(t);
 169
 170     t->userdata = userdata;
 171 }
 172
 173 void pa_thread_yield(void) {
 174 #ifdef HAVE_PTHREAD_YIELD
 175     pthread_yield();
 176 #else
 177     ASSERT_SUCCESS(sched_yield());
 178 #endif
 179 }
 180
 181 pa_tls* pa_tls_new(pa_free_cb_t free_cb) {
 182     pa_tls *t;
 183
 184     t = pa_xnew(pa_tls, 1);
 185
 186     if (pthread_key_create(&t->key, free_cb) < 0) {
 187         pa_xfree(t);
 188         return NULL;
 189     }
 190
 191     return t;
 192 }
 193
 194 void pa_tls_free(pa_tls *t) {
 195     assert(t);
 196
 197     ASSERT_SUCCESS(pthread_key_delete(t->key));
 198     pa_xfree(t);
 199 }
 200
 201 void *pa_tls_get(pa_tls *t) {
 202     assert(t);
 203
 204     return pthread_getspecific(t->key);
 205 }
 206
 207 void *pa_tls_set(pa_tls *t, void *userdata) {
 208     void *r;
 209
 210     r = pthread_getspecific(t->key);
 211     ASSERT_SUCCESS(pthread_setspecific(t->key, userdata));
 212     return r;
 213 }
 214