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  *
   7  * Authors: Pierre d'Herbemont
   8  *
   9  * This program is free software; you can redistribute it and/or modify it
  10  * under the terms of the GNU Lesser General Public License as published by
  11  * the Free Software Foundation; either version 2.1 of the License, or
  12  * (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  17  * GNU Lesser General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU Lesser General Public License
  20  * along with this program; if not, write to the Free Software Foundation,
  21  * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  22  *****************************************************************************/
  23
  24 #ifndef VLC_EVENTS_H
  25 # define VLC_EVENTS_H
  26
  27 #include <vlc_arrays.h>
  28 #include <vlc_meta.h>
  29
  30 /**
  31  * \file
  32  * This file is the interface definition for events
  33  * (implementation in src/misc/events.c)
  34  */
  35
  36 /*****************************************************************************
  37  * Documentation
  38  *****************************************************************************/
  39 /*
  40  **** Background
  41  *
  42  * This implements a way to send and receive event for an object (which can be
  43  * a simple C struct or less).
  44  *
  45  * This is in direct concurrency with the Variable based Callback
  46  * (see src/misc/variables.c).
  47  *
  48  * It has the following advantages over Variable based Callback:
  49  * - No need to implement the whole vlc_object_t in the object,
  50  * thus it reduce it size. This is especially true for input_item_t which
  51  * doesn't have vlc_object_t. This is the first reason of existence of
  52  * this implementation.
  53  * - Libvlc can easily be based upon that.
  54  * - Existing event are clearly declared (in include/vlc_events.h)
  55  *
  56  *
  57  **** Example usage
  58  *
  59  * (vlc_cool_object_t doesn't need to have the vlc_object_t.)
  60  *
  61  * struct vlc_cool_object_t
  62  * {
  63  *        ...
  64  *        vlc_event_manager_t p_event_manager;
  65  *        ...
  66  * }
  67  *
  68  * vlc_my_cool_object_new()
  69  * {
  70  *        ...
  71  *        vlc_event_manager_init( &p_self->p_event_manager, p_self, p_a_libvlc_object );
  72  *        ...
  73  * }
  74  *
  75  * vlc_my_cool_object_release()
  76  * {
  77  *         ...
  78  *         vlc_event_manager_fini( &p_self->p_event_manager );
  79  *         ...
  80  * }
  81  *
  82  * vlc_my_cool_object_do_something()
  83  * {
  84  *        ...
  85  *        vlc_event_t event;
  86  *        event.type = vlc_MyCoolObjectDidSomething;
  87  *        event.u.my_cool_object_did_something.what_it_did = kSomething;
  88  *        vlc_event_send( &p_self->p_event_manager, &event );
  89  * }
  90  * */
  91
  92   /*****************************************************************************
  93  * Event Type
  94  *****************************************************************************/
  95
  96 /* List of event */
  97 typedef enum vlc_event_type_t {
  98     /* Input item events */
  99     vlc_InputItemMetaChanged,
 100     vlc_InputItemDurationChanged,
 101     vlc_InputItemPreparsedChanged,
 102     vlc_InputItemNameChanged,
 103     vlc_InputItemInfoChanged,
 104     vlc_InputItemErrorWhenReadingChanged,
 105 } vlc_event_type_t;
 106
 107 typedef struct vlc_event_listeners_group_t
 108 {
 109     DECL_ARRAY(struct vlc_event_listener_t *) listeners;
 110 } vlc_event_listeners_group_t;
 111
 112 /* Event manager type */
 113 typedef struct vlc_event_manager_t
 114 {
 115     void * p_obj;
 116     vlc_mutex_t lock;
 117     vlc_event_listeners_group_t events[vlc_InputItemErrorWhenReadingChanged + 1];
 118 } vlc_event_manager_t;
 119
 120 /* Event definition */
 121 typedef struct vlc_event_t
 122 {
 123     vlc_event_type_t type;
 124     void * p_obj; /* Sender object, automatically filled by vlc_event_send() */
 125     union vlc_event_type_specific
 126     {
 127         /* Input item events */
 128         struct vlc_input_item_meta_changed
 129         {
 130             vlc_meta_type_t meta_type;
 131         } input_item_meta_changed;
 132         struct vlc_input_item_subitem_added
 133         {
 134             input_item_t * p_new_child;
 135         } input_item_subitem_added;
 136         struct vlc_input_item_subitem_tree_added
 137         {
 138             input_item_node_t * p_root;
 139         } input_item_subitem_tree_added;
 140         struct vlc_input_item_duration_changed
 141         {
 142             vlc_tick_t new_duration;
 143         } input_item_duration_changed;
 144         struct vlc_input_item_preparsed_changed
 145         {
 146             int new_status;
 147         } input_item_preparsed_changed;
 148         struct vlc_input_item_name_changed
 149         {
 150             const char * new_name;
 151         } input_item_name_changed;
 152         struct vlc_input_item_info_changed
 153         {
 154             void * unused;
 155         } input_item_info_changed;
 156         struct input_item_error_when_reading_changed
 157         {
 158             bool new_value;
 159         } input_item_error_when_reading_changed;
 160         struct input_item_preparse_ended
 161         {
 162             int new_status;
 163         } input_item_preparse_ended;
 164     } u;
 165 } vlc_event_t;
 166
 167 /* Event callback type */
 168 typedef void ( *vlc_event_callback_t )( const vlc_event_t *, void * );
 169
 170  /*****************************************************************************
 171  * Event manager
 172  *****************************************************************************/
 173
 174 /*
 175  * p_obj points to the object that owns the event manager, and from
 176  * which events are sent
 177  */
 178 void vlc_event_manager_init( vlc_event_manager_t * p_em, void * p_obj );
 179
 180 /*
 181  * Destroy
 182  */
 183 void vlc_event_manager_fini( vlc_event_manager_t * p_em );
 184
 185 /*
 186  * Send an event to the listener attached to this p_em.
 187  */
 188 void vlc_event_send( vlc_event_manager_t * p_em, vlc_event_t * );
 189
 190 /*
 191  * Add a callback for an event.
 192  */
 193 VLC_API int vlc_event_attach( vlc_event_manager_t * p_event_manager,
 194                               vlc_event_type_t event_type,
 195                               vlc_event_callback_t pf_callback,
 196                               void *p_user_data );
 197
 198 /*
 199  * Remove a callback for an event.
 200  */
 201 VLC_API void vlc_event_detach( vlc_event_manager_t *p_event_manager,
 202                                vlc_event_type_t event_type,
 203                                vlc_event_callback_t pf_callback,
 204                                void *p_user_data );
 205
 206 #endif /* VLC_EVENTS_H */