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_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     vlc_object_t *p_parent_object;
 109     DECL_ARRAY(struct vlc_event_listeners_group_t *) listeners_groups;
 110 } vlc_event_manager_t;
 111
 112 /* List of event */
 113 /* Be sure to keep sync-ed with misc/events.c debug name table */
 114 typedef enum vlc_event_type_t {
 115     /* Input (thread) events */
 116     vlc_InputStateChanged,
 117     vlc_InputSelectedStreamChanged,
 118
 119     /* Input item events */
 120     vlc_InputItemMetaChanged,
 121     vlc_InputItemSubItemAdded,
 122     vlc_InputItemDurationChanged,
 123     vlc_InputItemPreparsedChanged,
 124     vlc_InputItemNameChanged,
 125     vlc_InputItemInfoChanged,
 126     vlc_InputItemErrorWhenReadingChanged,
 127
 128     /* Service Discovery event */
 129     vlc_ServicesDiscoveryItemAdded,
 130     vlc_ServicesDiscoveryItemRemoved,
 131     vlc_ServicesDiscoveryStarted,
 132     vlc_ServicesDiscoveryEnded
 133 } vlc_event_type_t;
 134
 135 /* Event definition */
 136 typedef struct vlc_event_t
 137 {
 138     vlc_event_type_t type;
 139     void * p_obj; /* Sender object, automatically filled by vlc_event_send() */
 140     union vlc_event_type_specific
 141     {
 142         /* Input (thread) events */
 143         struct vlc_input_state_changed
 144         {
 145             int new_state;
 146         } input_state_changed;
 147         struct vlc_input_selected_stream_changed
 148         {
 149             void * unused;
 150         } input_selected_stream_changed;
 151
 152         /* Input item events */
 153         struct vlc_input_item_meta_changed
 154         {
 155             vlc_meta_type_t meta_type;
 156         } input_item_meta_changed;
 157         struct vlc_input_item_subitem_added
 158         {
 159             input_item_t * p_new_child;
 160         } input_item_subitem_added;
 161         struct vlc_input_item_duration_changed
 162         {
 163             mtime_t new_duration;
 164         } input_item_duration_changed;
 165         struct vlc_input_item_preparsed_changed
 166         {
 167             int new_status;
 168         } input_item_preparsed_changed;
 169         struct vlc_input_item_name_changed
 170         {
 171             const char * new_name;
 172         } input_item_name_changed;
 173         struct vlc_input_item_info_changed
 174         {
 175             void * unused;
 176         } input_item_info_changed;
 177         struct input_item_error_when_reading_changed
 178         {
 179             bool new_value;
 180         } input_item_error_when_reading_changed;
 181
 182         /* Service discovery events */
 183         struct vlc_services_discovery_item_added
 184         {
 185             input_item_t * p_new_item;
 186             const char * psz_category;
 187         } services_discovery_item_added;
 188         struct vlc_services_discovery_item_removed
 189         {
 190             input_item_t * p_item;
 191         } services_discovery_item_removed;
 192         struct vlc_services_discovery_started
 193         {
 194             void * unused;
 195         } services_discovery_started;
 196         struct vlc_services_discovery_ended
 197         {
 198             void * unused;
 199         } services_discovery_ended;
 200
 201     } u;
 202 } vlc_event_t;
 203
 204 /* Event callback type */
 205 typedef void ( *vlc_event_callback_t )( const vlc_event_t *, void * );
 206
 207  /*****************************************************************************
 208  * Event manager
 209  *****************************************************************************/
 210
 211 /*
 212  * p_obj points to the object that owns the event manager, and from
 213  * which events are sent
 214  * p_obj is here to give us a libvlc instance
 215  */
 216 #define vlc_event_manager_init_with_vlc_object(a,b) \
 217             vlc_event_manager_init( a, b, b )
 218
 219 #define vlc_event_manager_init(a,b,c) \
 220             __vlc_event_manager_init(a, b, VLC_OBJECT(c))
 221 VLC_EXPORT(int, __vlc_event_manager_init, ( vlc_event_manager_t * p_em,
 222                                           void * p_obj, vlc_object_t * ));
 223
 224 /*
 225  * Destroy
 226  */
 227 VLC_EXPORT(void, vlc_event_manager_fini, ( vlc_event_manager_t * p_em ));
 228
 229 /*
 230  * Tells a specific event manager that it will handle event_type object
 231  */
 232 VLC_EXPORT(int, vlc_event_manager_register_event_type,
 233                 ( vlc_event_manager_t * p_em, vlc_event_type_t event_type ));
 234
 235 /*
 236  * Send an event to the listener attached to this p_em.
 237  */
 238 VLC_EXPORT(void, vlc_event_send, ( vlc_event_manager_t * p_em,
 239                                    vlc_event_t * p_event ));
 240
 241 /*
 242  * Add a callback for an event.
 243  */
 244 #define vlc_event_attach(a, b, c, d) __vlc_event_attach(a, b, c, d, #c)
 245 VLC_EXPORT(int, __vlc_event_attach, ( vlc_event_manager_t * p_event_manager,
 246                                       vlc_event_type_t event_type,
 247                                       vlc_event_callback_t pf_callback,
 248                                       void *p_user_data,
 249                                       const char * psz_debug_name ));
 250
 251 /*
 252  * Remove a callback for an event.
 253  */
 254 VLC_EXPORT(int, vlc_event_detach, ( vlc_event_manager_t *p_event_manager,
 255                                     vlc_event_type_t event_type,
 256                                     vlc_event_callback_t pf_callback,
 257                                     void *p_user_data ));
 258
 259 #endif /* VLC_EVENTS_H */