include/vlc_events.h

   1 /*****************************************************************************
   2  * events.h: events definitions
   3  * Interface used to send events.
   4  *****************************************************************************
   5  * Copyright (C) 2007 the VideoLAN team
   6  * $Id$
   7  *
   8  * Authors: Pierre d'Herbemont
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License as published by
  12  * the Free Software Foundation; either version 2 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 General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, write to the Free Software
  22  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  23  *****************************************************************************/
  24
  25 #ifndef VLC_EVENTS_H
  26 # define VLC_EVENTS_H
  27
  28 #include <vlc_arrays.h>
  29 #include <vlc_meta.h>
  30
  31 /**
  32  * \file
  33  * This file is the interface definition for events
  34  * (implementation in src/misc/events.c)
  35  */
  36
  37 /*****************************************************************************
  38  * Documentation
  39  *****************************************************************************/
  40 /*
  41  **** Background
  42  *
  43  * This implements a way to send and receive event for an object (which can be
  44  * a simple C struct or less).
  45  *
  46  * This is in direct concurrency with the Variable based Callback
  47  * (see src/misc/variables.c).
  48  *
  49  * It has the following advantages over Variable based Callback:
  50  * - No need to implement the whole VLC_COMMON_MEMBERS in the object,
  51  * thus it reduce it size. This is especially true for input_item_t which
  52  * doesn't have VLC_COMMON_MEMBERS. This is the first reason of existence of
  53  * this implementation.
  54  * - Libvlc can easily be based upon that.
  55  * - Existing event are clearly declared (in include/vlc_events.h)
  56  *
  57  *
  58  **** Example usage
  59  *
  60  * (vlc_cool_object_t doesn't need to have the VLC_COMMON_MEMBERS.)
  61  *
  62  * struct vlc_cool_object_t
  63  * {
  64  *        ...
  65  *        vlc_event_manager_t p_event_manager;
  66  *        ...
  67  * }
  68  *
  69  * vlc_my_cool_object_new()
  70  * {
  71  *        ...
  72  *        vlc_event_manager_Create( &p_self->p_event_manager, p_this );
  73  *        vlc_event_manager_register_event_type(p_self->p_event_manager,
  74  *                vlc_MyCoolObjectDidSomething, p_e)
  75  *        ...
  76  * }
  77  *
  78  * vlc_my_cool_object_release()
  79  * {
  80  *         ...
  81  *         vlc_event_manager_release( p_self->p_event_manager );
  82  *         ...
  83  * }
  84  *
  85  * vlc_my_cool_object_do_something()
  86  * {
  87  *        ...
  88  *        vlc_event_t event;
  89  *        event.type = vlc_MyCoolObjectDidSomething;
  90  *        event.u.my_cool_object_did_something.what_it_did = kSomething;
  91  *        vlc_event_send( p_self->p_event_manager, &event );
  92  * }
  93  * */
  94
  95   /*****************************************************************************
  96  * Event Type
  97  *****************************************************************************/
  98
  99 /* Private structure defined in misc/events.c */
 100 struct vlc_event_listeners_group_t;
 101
 102 /* Event manager type */
 103 typedef struct vlc_event_manager_t
 104 {
 105     void * p_obj;
 106     vlc_mutex_t object_lock;
 107     vlc_object_t *p_parent_object;
 108     DECL_ARRAY(struct vlc_event_listeners_group_t *) listeners_groups;
 109 } vlc_event_manager_t;
 110
 111 /* List of event */
 112 /* Be sure to keep sync-ed with misc/events.c debug name table */
 113 typedef enum vlc_event_type_t {
 114     /* Input item events */
 115     vlc_InputItemMetaChanged,
 116     vlc_InputItemSubItemAdded,
 117     vlc_InputItemDurationChanged,
 118     vlc_InputItemPreparsedChanged,
 119
 120     /* Service Discovery event */
 121     vlc_ServicesDiscoveryItemAdded,
 122     vlc_ServicesDiscoveryItemRemoved
 123 } vlc_event_type_t;
 124
 125 /* Event definition */
 126 typedef struct vlc_event_t
 127 {
 128     vlc_event_type_t type;
 129     void * p_obj; /* Sender object, automatically filled by vlc_event_send() */
 130     union vlc_event_type_specific
 131     {
 132         /* Input item events */
 133         struct vlc_input_item_meta_changed
 134         {
 135             vlc_meta_type_t meta_type;
 136         } input_item_meta_changed;
 137         struct vlc_input_item_subitem_added
 138         {
 139             input_item_t * p_new_child;
 140         } input_item_subitem_added;
 141         struct vlc_input_item_duration_changed
 142         {
 143             mtime_t new_duration;
 144         } input_item_duration_changed;
 145         struct vlc_input_item_preparsed_changed
 146         {
 147             int new_status;
 148         } input_item_preparsed_changed;
 149
 150         /* Service discovery events */
 151         struct vlc_services_discovery_item_added
 152         {
 153             input_item_t * p_new_item;
 154             const char * psz_category;
 155         } services_discovery_item_added;
 156         struct vlc_services_discovery_item_removed
 157         {
 158             input_item_t * p_item;
 159         } services_discovery_item_removed;
 160
 161     } u;
 162 } vlc_event_t;
 163
 164 /* Event callback type */
 165 typedef void ( *vlc_event_callback_t )( const vlc_event_t *, void * );
 166
 167  /*****************************************************************************
 168  * Event manager
 169  *****************************************************************************/
 170
 171 /*
 172  * p_obj points to the object that owns the event manager, and from
 173  * which events are sent
 174  * p_obj is here to give us a libvlc instance
 175  */
 176 VLC_EXPORT(int, vlc_event_manager_init, ( vlc_event_manager_t * p_em,
 177                                           void * p_obj, vlc_object_t * ));
 178
 179 /*
 180  * Destroy
 181  */
 182 VLC_EXPORT(void, vlc_event_manager_fini, ( vlc_event_manager_t * p_em ));
 183
 184 /*
 185  * Tells a specific event manager that it will handle event_type object
 186  */
 187 VLC_EXPORT(int, vlc_event_manager_register_event_type,
 188                 ( vlc_event_manager_t * p_em, vlc_event_type_t event_type ));
 189
 190 /*
 191  * Send an event to the listener attached to this p_em.
 192  */
 193 VLC_EXPORT(void, vlc_event_send, ( vlc_event_manager_t * p_em,
 194                                    vlc_event_t * p_event ));
 195
 196 /*
 197  * Add a callback for an event.
 198  */
 199 #define vlc_event_attach(a, b, c, d) __vlc_event_attach(a, b, c, d, #c)
 200 VLC_EXPORT(int, __vlc_event_attach, ( vlc_event_manager_t * p_event_manager,
 201                                       vlc_event_type_t event_type,
 202                                       vlc_event_callback_t pf_callback,
 203                                       void *p_user_data,
 204                                       const char * psz_debug_name ));
 205
 206 /*
 207  * Remove a callback for an event.
 208  */
 209 VLC_EXPORT(int, vlc_event_detach, ( vlc_event_manager_t *p_event_manager,
 210                                     vlc_event_type_t event_type,
 211                                     vlc_event_callback_t pf_callback,
 212                                     void *p_user_data ));
 213
 214 #endif /* VLC_EVENTS_H */