include/vlc_events.h

   1 /*****************************************************************************
   2  * vlc_events.h: events definitions
   3  * Interface used to send events.
   4  *****************************************************************************
   5  * Copyright (C) 2007 VLC authors and VideoLAN
   6  * $Id$
   7  *
   8  * Authors: Pierre d'Herbemont
   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 #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_init( &p_self->p_event_manager, p_self, p_a_libvlc_object );
  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_fini( &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_mutex_t event_sending_lock;
 108     DECL_ARRAY(struct vlc_event_listeners_group_t *) listeners_groups;
 109 } vlc_event_manager_t;
 110
 111 /* List of event */
 112 typedef enum vlc_event_type_t {
 113     /* Input (thread) events */
 114     vlc_InputStateChanged,
 115     vlc_InputSelectedStreamChanged,
 116
 117     /* Input item events */
 118     vlc_InputItemMetaChanged,
 119     vlc_InputItemSubItemAdded,
 120     vlc_InputItemSubItemTreeAdded,
 121     vlc_InputItemDurationChanged,
 122     vlc_InputItemPreparsedChanged,
 123     vlc_InputItemNameChanged,
 124     vlc_InputItemInfoChanged,
 125     vlc_InputItemErrorWhenReadingChanged,
 126
 127     /* Service Discovery event */
 128     vlc_ServicesDiscoveryItemAdded,
 129     vlc_ServicesDiscoveryItemRemoved,
 130     vlc_ServicesDiscoveryStarted,
 131     vlc_ServicesDiscoveryEnded
 132 } vlc_event_type_t;
 133
 134 /* Event definition */
 135 typedef struct vlc_event_t
 136 {
 137     vlc_event_type_t type;
 138     void * p_obj; /* Sender object, automatically filled by vlc_event_send() */
 139     union vlc_event_type_specific
 140     {
 141         /* Input (thread) events */
 142         struct vlc_input_state_changed
 143         {
 144             int new_state;
 145         } input_state_changed;
 146         struct vlc_input_selected_stream_changed
 147         {
 148             void * unused;
 149         } input_selected_stream_changed;
 150
 151         /* Input item events */
 152         struct vlc_input_item_meta_changed
 153         {
 154             vlc_meta_type_t meta_type;
 155         } input_item_meta_changed;
 156         struct vlc_input_item_subitem_added
 157         {
 158             input_item_t * p_new_child;
 159         } input_item_subitem_added;
 160         struct vlc_input_item_subitem_tree_added
 161         {
 162             input_item_node_t * p_root;
 163         } input_item_subitem_tree_added;
 164         struct vlc_input_item_duration_changed
 165         {
 166             mtime_t new_duration;
 167         } input_item_duration_changed;
 168         struct vlc_input_item_preparsed_changed
 169         {
 170             int new_status;
 171         } input_item_preparsed_changed;
 172         struct vlc_input_item_name_changed
 173         {
 174             const char * new_name;
 175         } input_item_name_changed;
 176         struct vlc_input_item_info_changed
 177         {
 178             void * unused;
 179         } input_item_info_changed;
 180         struct input_item_error_when_reading_changed
 181         {
 182             bool new_value;
 183         } input_item_error_when_reading_changed;
 184
 185         /* Service discovery events */
 186         struct vlc_services_discovery_item_added
 187         {
 188             input_item_t * p_new_item;
 189             const char * psz_category;
 190         } services_discovery_item_added;
 191         struct vlc_services_discovery_item_removed
 192         {
 193             input_item_t * p_item;
 194         } services_discovery_item_removed;
 195         struct vlc_services_discovery_started
 196         {
 197             void * unused;
 198         } services_discovery_started;
 199         struct vlc_services_discovery_ended
 200         {
 201             void * unused;
 202         } services_discovery_ended;
 203
 204     } u;
 205 } vlc_event_t;
 206
 207 /* Event callback type */
 208 typedef void ( *vlc_event_callback_t )( const vlc_event_t *, void * );
 209
 210  /*****************************************************************************
 211  * Event manager
 212  *****************************************************************************/
 213
 214 /*
 215  * p_obj points to the object that owns the event manager, and from
 216  * which events are sent
 217  */
 218 VLC_API int vlc_event_manager_init( vlc_event_manager_t * p_em, void * p_obj );
 219
 220 /*
 221  * Destroy
 222  */
 223 VLC_API void vlc_event_manager_fini( vlc_event_manager_t * p_em );
 224
 225 /*
 226  * Tells a specific event manager that it will handle event_type object
 227  */
 228 VLC_API int vlc_event_manager_register_event_type( vlc_event_manager_t * p_em,
 229                                                    vlc_event_type_t );
 230
 231 /*
 232  * Send an event to the listener attached to this p_em.
 233  */
 234 VLC_API void vlc_event_send( vlc_event_manager_t * p_em, vlc_event_t * );
 235
 236 /*
 237  * Add a callback for an event.
 238  */
 239 VLC_API int vlc_event_attach( vlc_event_manager_t * p_event_manager,
 240                               vlc_event_type_t event_type,
 241                               vlc_event_callback_t pf_callback,
 242                               void *p_user_data );
 243
 244 /*
 245  * Remove a callback for an event.
 246  */
 247 VLC_API void vlc_event_detach( vlc_event_manager_t *p_event_manager,
 248                                vlc_event_type_t event_type,
 249                                vlc_event_callback_t pf_callback,
 250                                void *p_user_data );
 251
 252 #endif /* VLC_EVENTS_H */