modules/video_output/win32/inhibit.c

   1 /*****************************************************************************
   2  * inhibit.c: Windows video output common code
   3  *****************************************************************************
   4  * Copyright (C) 2018 VLC authors and VideoLAN
   5  *
   6  * Authors: Steve Lhomme <robux4@ycbcr.xyz>
   7  *
   8  * This program is free software; you can redistribute it and/or modify it
   9  * under the terms of the GNU Lesser General Public License as published by
  10  * the Free Software Foundation; either version 2.1 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  16  * GNU Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public License
  19  * along with this program; if not, write to the Free Software Foundation,
  20  * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  21  *****************************************************************************/
  22
  23 #ifdef HAVE_CONFIG_H
  24 # include "config.h"
  25 #endif
  26
  27 #include <vlc_common.h>
  28 #include <vlc_inhibit.h>
  29 #include <vlc_plugin.h>
  30 #include <assert.h>
  31
  32 struct vlc_inhibit_sys
  33 {
  34     vlc_sem_t sem;
  35     vlc_mutex_t mutex;
  36     vlc_cond_t cond;
  37     vlc_thread_t thread;
  38     bool signaled;
  39     unsigned int mask;
  40 };
  41
  42 static void Inhibit (vlc_inhibit_t *ih, unsigned mask)
  43 {
  44     vlc_inhibit_sys_t *sys = ih->p_sys;
  45     vlc_mutex_lock(&sys->mutex);
  46     sys->mask = mask;
  47     sys->signaled = true;
  48     vlc_mutex_unlock(&sys->mutex);
  49     vlc_cond_signal(&sys->cond);
  50 }
  51
  52 static void* Run(void* obj)
  53 {
  54     vlc_inhibit_t *ih = (vlc_inhibit_t*)obj;
  55     vlc_inhibit_sys_t *sys = ih->p_sys;
  56     EXECUTION_STATE prev_state = ES_CONTINUOUS;
  57
  58     vlc_sem_post(&sys->sem);
  59     while (true)
  60     {
  61         unsigned int mask;
  62
  63         vlc_mutex_lock(&sys->mutex);
  64         mutex_cleanup_push(&sys->mutex);
  65         while (!sys->signaled)
  66             vlc_cond_wait(&sys->cond, &sys->mutex);
  67         mask = sys->mask;
  68         sys->signaled = false;
  69         vlc_mutex_unlock(&sys->mutex);
  70         vlc_cleanup_pop();
  71
  72         bool suspend = (mask & VLC_INHIBIT_DISPLAY) != 0;
  73         if (suspend)
  74             /* Prevent monitor from powering off */
  75             prev_state = SetThreadExecutionState( ES_DISPLAY_REQUIRED |
  76                                                   ES_SYSTEM_REQUIRED |
  77                                                   ES_CONTINUOUS );
  78         else
  79             SetThreadExecutionState( prev_state );
  80     }
  81     vlc_assert_unreachable();
  82 }
  83
  84 static void CloseInhibit (vlc_object_t *obj)
  85 {
  86     vlc_inhibit_t *ih = (vlc_inhibit_t*)obj;
  87     vlc_inhibit_sys_t* sys = ih->p_sys;
  88     vlc_cancel(sys->thread);
  89     vlc_join(sys->thread, NULL);
  90     vlc_cond_destroy(&sys->cond);
  91     vlc_mutex_destroy(&sys->mutex);
  92     vlc_sem_destroy(&sys->sem);
  93 }
  94
  95 static int OpenInhibit (vlc_object_t *obj)
  96 {
  97     vlc_inhibit_t *ih = (vlc_inhibit_t *)obj;
  98     vlc_inhibit_sys_t *sys = ih->p_sys =
  99             vlc_obj_malloc(obj, sizeof(vlc_inhibit_sys_t));
 100     if (unlikely(ih->p_sys == NULL))
 101         return VLC_ENOMEM;
 102
 103     vlc_sem_init(&sys->sem, 0);
 104     vlc_mutex_init(&sys->mutex);
 105     vlc_cond_init(&sys->cond);
 106     sys->signaled = false;
 107
 108     /* SetThreadExecutionState always needs to be called from the same thread */
 109     if (vlc_clone(&sys->thread, Run, ih, VLC_THREAD_PRIORITY_LOW))
 110     {
 111         vlc_cond_destroy(&sys->cond);
 112         vlc_mutex_destroy(&sys->mutex);
 113         vlc_sem_destroy(&sys->sem);
 114         return VLC_EGENERIC;
 115     }
 116
 117     vlc_sem_wait(&sys->sem);
 118
 119     ih->inhibit = Inhibit;
 120     return VLC_SUCCESS;
 121 }
 122
 123 vlc_module_begin ()
 124     set_shortname (N_("Windows screensaver"))
 125     set_description (N_("Windows screen saver inhibition"))
 126     set_category (CAT_ADVANCED)
 127     set_subcategory (SUBCAT_ADVANCED_MISC)
 128     set_capability ("inhibit", 10)
 129     set_callbacks (OpenInhibit, CloseInhibit)
 130 vlc_module_end ()