code.delx.au - pulseaudio/blob - src/pulsecore/once-win32.c

   1 /* $Id$ */
   2
   3 /***
   4   This file is part of PulseAudio.
   5
   6   Copyright 2006 Pierre Ossman <ossman@cendio.se> for Cendio AB
   7
   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 published
  10   by the Free Software Foundation; either version 2 of the License,
  11   or (at your option) any later version.
  12
  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   General Public License for more details.
  17
  18   You should have received a copy of the GNU Lesser General Public License
  19   along with PulseAudio; if not, write to the Free Software
  20   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
  21   USA.
  22 ***/
  23
  24 #ifdef HAVE_CONFIG_H
  25 #include <config.h>
  26 #endif
  27
  28 #include <assert.h>
  29 #include <stdio.h>
  30
  31 #include <windows.h>
  32
  33 #include <pulsecore/mutex.h>
  34
  35 #include "once.h"
  36
  37 void pa_once(pa_once_t *control, pa_once_func_t func) {
  38     HANDLE mutex;
  39     char name[64];
  40
  41     assert(control);
  42     assert(func);
  43
  44     /* Create the global mutex */
  45     sprintf(name, "pulse%d", (int)GetCurrentProcessId());
  46
  47     mutex = CreateMutex(NULL, FALSE, name);
  48     assert(mutex);
  49
  50     /* Create the local mutex */
  51     WaitForSingleObject(mutex, INFINITE);
  52     if (!control->mutex)
  53         control->mutex = pa_mutex_new(1);
  54     ReleaseMutex(mutex);
  55
  56     CloseHandle(mutex);
  57
  58     /* Execute function */
  59     pa_mutex_lock(control->mutex);
  60     if (!control->once_value) {
  61         control->once_value = 1;
  62         func();
  63     }
  64     pa_mutex_unlock(control->mutex);
  65
  66     /* Caveat: We have to make sure that the once func has completed
  67      * before returning, even if the once func is not actually
  68      * executed by us. Hence the awkward locking. */
  69 }