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

   1 /* $Id$ */
   2
   3 /***
   4   This file is part of PulseAudio.
   5
   6   Copyright 2006 Lennart Poettering
   7   Copyright 2006 Pierre Ossman <ossman@cendio.se> for Cendio AB
   8
   9   PulseAudio is free software; you can redistribute it and/or modify
  10   it under the terms of the GNU Lesser General Public License as published
  11   by the Free Software Foundation; either version 2 of the License,
  12   or (at your option) any later version.
  13
  14   PulseAudio is distributed in the hope that it will be useful, but
  15   WITHOUT ANY WARRANTY; without even the implied warranty of
  16   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  17   General Public License for more details.
  18
  19   You should have received a copy of the GNU Lesser General Public License
  20   along with PulseAudio; if not, write to the Free Software
  21   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
  22   USA.
  23 ***/
  24
  25 #ifdef HAVE_CONFIG_H
  26 #include <config.h>
  27 #endif
  28
  29 #include <assert.h>
  30 #include <pthread.h>
  31 #include <sched.h>
  32 #include <errno.h>
  33
  34 #include <pulse/xmalloc.h>
  35 #include <pulsecore/mutex.h>
  36 #include <pulsecore/once.h>
  37 #include <pulsecore/atomic.h>
  38
  39 #include "thread.h"
  40
  41 #define ASSERT_SUCCESS(x) do { \
  42     int _r = (x); \
  43     assert(_r == 0); \
  44 } while(0)
  45
  46 struct pa_thread {
  47     pthread_t id;
  48     pa_thread_func_t thread_func;
  49     void *userdata;
  50     pa_atomic_int_t running;
  51 };
  52
  53 struct pa_tls {
  54     pthread_key_t key;
  55 };
  56
  57 static pa_tls *thread_tls;
  58 static pa_once_t thread_tls_once = PA_ONCE_INIT;
  59
  60 static void tls_free_cb(void *p) {
  61     pa_thread *t = p;
  62
  63     assert(t);
  64
  65     if (!t->thread_func)
  66         /* This is a foreign thread, we need to free the struct */
  67         pa_xfree(t);
  68 }
  69
  70 static void thread_tls_once_func(void) {
  71     thread_tls = pa_tls_new(tls_free_cb);
  72     assert(thread_tls);
  73 }
  74
  75 static void* internal_thread_func(void *userdata) {
  76     pa_thread *t = userdata;
  77     assert(t);
  78
  79     t->id = pthread_self();
  80
  81     pa_once(&thread_tls_once, thread_tls_once_func);
  82
  83     pa_tls_set(thread_tls, t);
  84
  85     pa_atomic_inc(&t->running);
  86     t->thread_func(t->userdata);
  87     pa_atomic_add(&t->running, -2);
  88
  89     return NULL;
  90 }
  91
  92 pa_thread* pa_thread_new(pa_thread_func_t thread_func, void *userdata) {
  93     pa_thread *t;
  94
  95     assert(thread_func);
  96
  97     t = pa_xnew(pa_thread, 1);
  98     t->thread_func = thread_func;
  99     t->userdata = userdata;
 100     pa_atomic_store(&t->running, 0);
 101
 102     if (pthread_create(&t->id, NULL, internal_thread_func, t) < 0) {
 103         pa_xfree(t);
 104         return NULL;
 105     }
 106
 107     pa_atomic_inc(&t->running);
 108
 109     return t;
 110 }
 111
 112 int pa_thread_is_running(pa_thread *t) {
 113     assert(t);
 114
 115     /* Unfortunately there is no way to tell whether a "foreign"
 116      * thread is still running. See
 117      * http://udrepper.livejournal.com/16844.html for more
 118      * information */
 119     assert(t->thread_func);
 120
 121     return pa_atomic_load(&t->running) > 0;
 122 }
 123
 124 void pa_thread_free(pa_thread *t) {
 125     assert(t);
 126
 127     pa_thread_join(t);
 128     pa_xfree(t);
 129 }
 130
 131 int pa_thread_join(pa_thread *t) {
 132     assert(t);
 133
 134     return pthread_join(t->id, NULL);
 135 }
 136
 137 pa_thread* pa_thread_self(void) {
 138     pa_thread *t;
 139
 140     pa_once(&thread_tls_once, thread_tls_once_func);
 141
 142     if ((t = pa_tls_get(thread_tls)))
 143         return t;
 144
 145     /* This is a foreign thread, let's create a pthread structure to
 146      * make sure that we can always return a sensible pointer */
 147
 148     t = pa_xnew(pa_thread, 1);
 149     t->id = pthread_self();
 150     t->thread_func = NULL;
 151     t->userdata = NULL;
 152     pa_atomic_store(&t->running, 2);
 153
 154     pa_tls_set(thread_tls, t);
 155
 156     return t;
 157 }
 158
 159 void* pa_thread_get_data(pa_thread *t) {
 160     assert(t);
 161
 162     return t->userdata;
 163 }
 164
 165 void pa_thread_set_data(pa_thread *t, void *userdata) {
 166     assert(t);
 167
 168     t->userdata = userdata;
 169 }
 170
 171 void pa_thread_yield(void) {
 172 #ifdef HAVE_PTHREAD_YIELD
 173     pthread_yield();
 174 #else
 175     ASSERT_SUCCESS(sched_yield());
 176 #endif
 177 }
 178
 179 pa_tls* pa_tls_new(pa_free_cb_t free_cb) {
 180     pa_tls *t;
 181
 182     t = pa_xnew(pa_tls, 1);
 183
 184     if (pthread_key_create(&t->key, free_cb) < 0) {
 185         pa_xfree(t);
 186         return NULL;
 187     }
 188
 189     return t;
 190 }
 191
 192 void pa_tls_free(pa_tls *t) {
 193     assert(t);
 194
 195     ASSERT_SUCCESS(pthread_key_delete(t->key));
 196     pa_xfree(t);
 197 }
 198
 199 void *pa_tls_get(pa_tls *t) {
 200     assert(t);
 201
 202     return pthread_getspecific(t->key);
 203 }
 204
 205 void *pa_tls_set(pa_tls *t, void *userdata) {
 206     void *r;
 207
 208     r = pthread_getspecific(t->key);
 209     ASSERT_SUCCESS(pthread_setspecific(t->key, userdata));
 210     return r;
 211 }
 212