lib/event.c

   1 /*****************************************************************************
   2  * event.c: New libvlc event control API
   3  *****************************************************************************
   4  * Copyright (C) 2007-2010 VLC authors and VideoLAN
   5  * $Id $
   6  *
   7  * Authors: Filippo Carone <filippo@carone.org>
   8  *          Pierre d'Herbemont <pdherbemont # videolan.org>
   9  *
  10  * This program is free software; you can redistribute it and/or modify it
  11  * under the terms of the GNU Lesser General Public License as published by
  12  * the Free Software Foundation; either version 2.1 of the License, or
  13  * (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  18  * GNU Lesser General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU Lesser General Public License
  21  * along with this program; if not, write to the Free Software Foundation,
  22  * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  23  *****************************************************************************/
  24
  25 #ifdef HAVE_CONFIG_H
  26 # include "config.h"
  27 #endif
  28
  29 #include <assert.h>
  30 #include <errno.h>
  31
  32 #include <vlc/libvlc.h>
  33 #include "libvlc_internal.h"
  34
  35 #include <vlc_common.h>
  36
  37 /*
  38  * Event Handling
  39  */
  40
  41 /* Example usage
  42  *
  43  * struct libvlc_cool_object_t
  44  * {
  45  *        ...
  46  *        libvlc_event_manager_t event_manager;
  47  *        ...
  48  * }
  49  *
  50  * libvlc_my_cool_object_new()
  51  * {
  52  *        ...
  53  *        libvlc_event_manager_init(&p_self->event_manager, p_self)
  54  *        ...
  55  * }
  56  *
  57  * libvlc_my_cool_object_release()
  58  * {
  59  *         ...
  60  *         libvlc_event_manager_release(&p_self->event_manager);
  61  *         ...
  62  * }
  63  *
  64  * libvlc_my_cool_object_do_something()
  65  * {
  66  *        ...
  67  *        libvlc_event_t event;
  68  *        event.type = libvlc_MyCoolObjectDidSomething;
  69  *        event.u.my_cool_object_did_something.what_it_did = kSomething;
  70  *        libvlc_event_send(&p_self->event_manager, &event);
  71  * }
  72  * */
  73
  74 typedef struct libvlc_event_listener_t
  75 {
  76     libvlc_event_type_t event_type;
  77     void *              p_user_data;
  78     libvlc_callback_t   pf_callback;
  79 } libvlc_event_listener_t;
  80
  81 /*
  82  * Internal libvlc functions
  83  */
  84
  85 void libvlc_event_manager_init(libvlc_event_manager_t *em, void *obj)
  86 {
  87     em->p_obj = obj;
  88     vlc_array_init(&em->listeners);
  89     vlc_mutex_init_recursive(&em->lock);
  90 }
  91
  92 void libvlc_event_manager_destroy(libvlc_event_manager_t *em)
  93 {
  94     vlc_mutex_destroy(&em->lock);
  95
  96     for (size_t i = 0; i < vlc_array_count(&em->listeners); i++)
  97         free(vlc_array_item_at_index(&em->listeners, i));
  98
  99     vlc_array_clear(&em->listeners);
 100 }
 101
 102 /**************************************************************************
 103  *       libvlc_event_send (internal) :
 104  *
 105  * Send a callback.
 106  **************************************************************************/
 107 void libvlc_event_send( libvlc_event_manager_t * p_em,
 108                         libvlc_event_t * p_event )
 109 {
 110     /* Fill event with the sending object now */
 111     p_event->p_obj = p_em->p_obj;
 112
 113     vlc_mutex_lock(&p_em->lock);
 114     for (size_t i = 0; i < vlc_array_count(&p_em->listeners); i++)
 115     {
 116         libvlc_event_listener_t *listener;
 117
 118         listener = vlc_array_item_at_index(&p_em->listeners, i);
 119         if (listener->event_type == p_event->type)
 120             listener->pf_callback(p_event, listener->p_user_data);
 121     }
 122     vlc_mutex_unlock(&p_em->lock);
 123 }
 124
 125 /*
 126  * Public libvlc functions
 127  */
 128
 129 /**************************************************************************
 130  *       libvlc_event_attach (public) :
 131  *
 132  * Add a callback for an event.
 133  **************************************************************************/
 134 int libvlc_event_attach(libvlc_event_manager_t *em, libvlc_event_type_t type,
 135                         libvlc_callback_t callback, void *opaque)
 136 {
 137     libvlc_event_listener_t *listener = malloc(sizeof (*listener));
 138     if (unlikely(listener == NULL))
 139         return ENOMEM;
 140
 141     listener->event_type = type;
 142     listener->p_user_data = opaque;
 143     listener->pf_callback = callback;
 144
 145     int i_ret;
 146     vlc_mutex_lock(&em->lock);
 147     if(vlc_array_append(&em->listeners, listener) != 0)
 148     {
 149         i_ret = VLC_EGENERIC;
 150         free(listener);
 151     }
 152     else
 153         i_ret = VLC_SUCCESS;
 154     vlc_mutex_unlock(&em->lock);
 155     return i_ret;
 156 }
 157
 158 /**************************************************************************
 159  *       libvlc_event_detach (public) :
 160  *
 161  * Remove a callback for an event.
 162  **************************************************************************/
 163 void libvlc_event_detach(libvlc_event_manager_t *em, libvlc_event_type_t type,
 164                          libvlc_callback_t callback, void *opaque)
 165 {
 166     vlc_mutex_lock(&em->lock);
 167     for (size_t i = 0; i < vlc_array_count(&em->listeners); i++)
 168     {
 169          libvlc_event_listener_t *listener;
 170
 171          listener = vlc_array_item_at_index(&em->listeners, i);
 172
 173          if (listener->event_type == type
 174           && listener->pf_callback == callback
 175           && listener->p_user_data == opaque)
 176          {   /* that's our listener */
 177              vlc_array_remove(&em->listeners, i);
 178              vlc_mutex_unlock(&em->lock);
 179              free(listener);
 180              return;
 181          }
 182     }
 183     abort();
 184 }