src/misc/events.c

   1 /*****************************************************************************
   2  * events.c: events interface
   3  * This library provides an interface to the send and receive events.
   4  * It is more lightweight than variable based callback.
   5  *****************************************************************************
   6  * Copyright (C) 1998-2005 VLC authors and VideoLAN
   7  * $Id$
   8  *
   9  * Authors: Pierre d'Herbemont <pdherbemont # videolan.org >
  10  *
  11  * This program is free software; you can redistribute it and/or modify it
  12  * under the terms of the GNU Lesser General Public License as published by
  13  * the Free Software Foundation; either version 2.1 of the License, or
  14  * (at your option) any later version.
  15  *
  16  * This program is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  19  * GNU Lesser General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU Lesser General Public License
  22  * along with this program; if not, write to the Free Software Foundation,
  23  * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  24  *****************************************************************************/
  25
  26 /*****************************************************************************
  27  * Preamble
  28  *****************************************************************************/
  29
  30 #ifdef HAVE_CONFIG_H
  31 # include "config.h"
  32 #endif
  33
  34 #include <vlc_common.h>
  35
  36 #include <assert.h>
  37
  38 #include <vlc_events.h>
  39 #include <vlc_arrays.h>
  40
  41 /*****************************************************************************
  42  * Documentation : Read vlc_events.h
  43  *****************************************************************************/
  44
  45 /*****************************************************************************
  46  *  Private types.
  47  *****************************************************************************/
  48
  49 typedef struct vlc_event_listener_t
  50 {
  51     void *               p_user_data;
  52     vlc_event_callback_t pf_callback;
  53 } vlc_event_listener_t;
  54
  55 /*****************************************************************************
  56  *
  57  *****************************************************************************/
  58
  59 #undef vlc_event_manager_init
  60 /**
  61  * Initialize event manager object
  62  * p_obj is the object that contains the event manager. But not
  63  * necessarily a vlc_object_t (an input_item_t is not a vlc_object_t
  64  * for instance).
  65  */
  66 void vlc_event_manager_init( vlc_event_manager_t * p_em, void * p_obj )
  67 {
  68     p_em->p_obj = p_obj;
  69     /* This is an unsafe work-around for a long-standing playlist bug.
  70      * Do not rely on this. */
  71     vlc_mutex_init_recursive( &p_em->lock );
  72
  73     for( size_t i = 0; i < ARRAY_SIZE(p_em->events); i++ )
  74        ARRAY_INIT( p_em->events[i].listeners );
  75 }
  76
  77 /**
  78  * Destroy the event manager
  79  */
  80 void vlc_event_manager_fini( vlc_event_manager_t * p_em )
  81 {
  82     struct vlc_event_listener_t * listener;
  83
  84     vlc_mutex_destroy( &p_em->lock );
  85
  86     for( size_t i = 0; i < ARRAY_SIZE(p_em->events); i++ )
  87     {
  88         struct vlc_event_listeners_group_t *slot = p_em->events + i;
  89
  90         ARRAY_FOREACH( listener, slot->listeners )
  91             free( listener );
  92
  93         ARRAY_RESET( slot->listeners );
  94     }
  95 }
  96
  97 /**
  98  * Send an event to the listener attached to this p_em.
  99  */
 100 void vlc_event_send( vlc_event_manager_t * p_em,
 101                      vlc_event_t * p_event )
 102 {
 103     vlc_event_listeners_group_t *slot = &p_em->events[p_event->type];
 104     vlc_event_listener_t * listener;
 105
 106     /* Fill event with the sending object now */
 107     p_event->p_obj = p_em->p_obj;
 108
 109     vlc_mutex_lock( &p_em->lock ) ;
 110
 111     ARRAY_FOREACH( listener, slot->listeners )
 112         listener->pf_callback( p_event, listener->p_user_data );
 113
 114     vlc_mutex_unlock( &p_em->lock );
 115 }
 116
 117 #undef vlc_event_attach
 118 /**
 119  * Add a callback for an event.
 120  */
 121 int vlc_event_attach( vlc_event_manager_t * p_em,
 122                       vlc_event_type_t event_type,
 123                       vlc_event_callback_t pf_callback,
 124                       void *p_user_data )
 125 {
 126     vlc_event_listener_t * listener;
 127     vlc_event_listeners_group_t *slot = &p_em->events[event_type];
 128
 129     listener = malloc(sizeof(vlc_event_listener_t));
 130     if( !listener )
 131         return VLC_ENOMEM;
 132
 133     listener->p_user_data = p_user_data;
 134     listener->pf_callback = pf_callback;
 135
 136     vlc_mutex_lock( &p_em->lock );
 137     ARRAY_APPEND( slot->listeners, listener );
 138     vlc_mutex_unlock( &p_em->lock );
 139     return VLC_SUCCESS;
 140 }
 141
 142 /**
 143  * Remove a callback for an event.
 144  */
 145
 146 void vlc_event_detach( vlc_event_manager_t *p_em,
 147                        vlc_event_type_t event_type,
 148                        vlc_event_callback_t pf_callback,
 149                        void *p_user_data )
 150 {
 151     vlc_event_listeners_group_t *slot = &p_em->events[event_type];
 152
 153     vlc_mutex_lock( &p_em->lock );
 154
 155     for (int i = 0; i < slot->listeners.i_size; ++i)
 156     {
 157         struct vlc_event_listener_t *listener = slot->listeners.p_elems[i];
 158         if( listener->pf_callback == pf_callback &&
 159             listener->p_user_data == p_user_data )
 160         {
 161             /* that's our listener */
 162             ARRAY_REMOVE( slot->listeners, i );
 163             vlc_mutex_unlock( &p_em->lock );
 164             free( listener );
 165             return;
 166         }
 167     }
 168
 169     vlc_assert_unreachable();
 170 }