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_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 item events */
 116     vlc_InputItemMetaChanged,
 117     vlc_InputItemSubItemAdded,
 118     vlc_InputItemDurationChanged,
 119     vlc_InputItemPreparsedChanged,
 120
 121     /* Service Discovery event */
 122     vlc_ServicesDiscoveryItemAdded,
 123     vlc_ServicesDiscoveryItemRemoved,
 124     vlc_ServicesDiscoveryStarted,
 125     vlc_ServicesDiscoveryEnded
 126 } vlc_event_type_t;
 127
 128 /* Event definition */
 129 typedef struct vlc_event_t
 130 {
 131     vlc_event_type_t type;
 132     void * p_obj; /* Sender object, automatically filled by vlc_event_send() */
 133     union vlc_event_type_specific
 134     {
 135         /* Input item events */
 136         struct vlc_input_item_meta_changed
 137         {
 138             vlc_meta_type_t meta_type;
 139         } input_item_meta_changed;
 140         struct vlc_input_item_subitem_added
 141         {
 142             input_item_t * p_new_child;
 143         } input_item_subitem_added;
 144         struct vlc_input_item_duration_changed
 145         {
 146             mtime_t new_duration;
 147         } input_item_duration_changed;
 148         struct vlc_input_item_preparsed_changed
 149         {
 150             int new_status;
 151         } input_item_preparsed_changed;
 152
 153         /* Service discovery events */
 154         struct vlc_services_discovery_item_added
 155         {
 156             input_item_t * p_new_item;
 157             const char * psz_category;
 158         } services_discovery_item_added;
 159         struct vlc_services_discovery_item_removed
 160         {
 161             input_item_t * p_item;
 162         } services_discovery_item_removed;
 163         struct vlc_services_discovery_started
 164         {
 165             void * unused;
 166         } services_discovery_started;
 167         struct vlc_services_discovery_ended
 168         {
 169             void * unused;
 170         } services_discovery_ended;
 171
 172     } u;
 173 } vlc_event_t;
 174
 175 /* Event callback type */
 176 typedef void ( *vlc_event_callback_t )( const vlc_event_t *, void * );
 177
 178  /*****************************************************************************
 179  * Event manager
 180  *****************************************************************************/
 181
 182 /*
 183  * p_obj points to the object that owns the event manager, and from
 184  * which events are sent
 185  * p_obj is here to give us a libvlc instance
 186  */
 187 VLC_EXPORT(int, vlc_event_manager_init, ( vlc_event_manager_t * p_em,
 188                                           void * p_obj, vlc_object_t * ));
 189
 190 /*
 191  * Destroy
 192  */
 193 VLC_EXPORT(void, vlc_event_manager_fini, ( vlc_event_manager_t * p_em ));
 194
 195 /*
 196  * Tells a specific event manager that it will handle event_type object
 197  */
 198 VLC_EXPORT(int, vlc_event_manager_register_event_type,
 199                 ( vlc_event_manager_t * p_em, vlc_event_type_t event_type ));
 200
 201 /*
 202  * Send an event to the listener attached to this p_em.
 203  */
 204 VLC_EXPORT(void, vlc_event_send, ( vlc_event_manager_t * p_em,
 205                                    vlc_event_t * p_event ));
 206
 207 /*
 208  * Add a callback for an event.
 209  */
 210 #define vlc_event_attach(a, b, c, d) __vlc_event_attach(a, b, c, d, #c)
 211 VLC_EXPORT(int, __vlc_event_attach, ( vlc_event_manager_t * p_event_manager,
 212                                       vlc_event_type_t event_type,
 213                                       vlc_event_callback_t pf_callback,
 214                                       void *p_user_data,
 215                                       const char * psz_debug_name ));
 216
 217 /*
 218  * Remove a callback for an event.
 219  */
 220 VLC_EXPORT(int, vlc_event_detach, ( vlc_event_manager_t *p_event_manager,
 221                                     vlc_event_type_t event_type,
 222                                     vlc_event_callback_t pf_callback,
 223                                     void *p_user_data ));
 224
 225 #endif /* VLC_EVENTS_H */