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  *        ...
  74  * }
  75  *
  76  * vlc_my_cool_object_release()
  77  * {
  78  *         ...
  79  *         vlc_event_manager_fini( &p_self->p_event_manager );
  80  *         ...
  81  * }
  82  *
  83  * vlc_my_cool_object_do_something()
  84  * {
  85  *        ...
  86  *        vlc_event_t event;
  87  *        event.type = vlc_MyCoolObjectDidSomething;
  88  *        event.u.my_cool_object_did_something.what_it_did = kSomething;
  89  *        vlc_event_send( &p_self->p_event_manager, &event );
  90  * }
  91  * */
  92
  93   /*****************************************************************************
  94  * Event Type
  95  *****************************************************************************/
  96
  97 /* List of event */
  98 typedef enum vlc_event_type_t {
  99     /* Input item events */
 100     vlc_InputItemMetaChanged,
 101     vlc_InputItemDurationChanged,
 102     vlc_InputItemPreparsedChanged,
 103     vlc_InputItemNameChanged,
 104     vlc_InputItemInfoChanged,
 105     vlc_InputItemErrorWhenReadingChanged,
 106 } vlc_event_type_t;
 107
 108 typedef struct vlc_event_listeners_group_t
 109 {
 110     DECL_ARRAY(struct vlc_event_listener_t *) listeners;
 111 } vlc_event_listeners_group_t;
 112
 113 /* Event manager type */
 114 typedef struct vlc_event_manager_t
 115 {
 116     void * p_obj;
 117     vlc_mutex_t lock;
 118     vlc_event_listeners_group_t events[vlc_InputItemErrorWhenReadingChanged + 1];
 119 } vlc_event_manager_t;
 120
 121 /* Event definition */
 122 typedef struct vlc_event_t
 123 {
 124     vlc_event_type_t type;
 125     void * p_obj; /* Sender object, automatically filled by vlc_event_send() */
 126     union vlc_event_type_specific
 127     {
 128         /* Input item events */
 129         struct vlc_input_item_meta_changed
 130         {
 131             vlc_meta_type_t meta_type;
 132         } input_item_meta_changed;
 133         struct vlc_input_item_subitem_added
 134         {
 135             input_item_t * p_new_child;
 136         } input_item_subitem_added;
 137         struct vlc_input_item_subitem_tree_added
 138         {
 139             input_item_node_t * p_root;
 140         } input_item_subitem_tree_added;
 141         struct vlc_input_item_duration_changed
 142         {
 143             vlc_tick_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         struct vlc_input_item_name_changed
 150         {
 151             const char * new_name;
 152         } input_item_name_changed;
 153         struct vlc_input_item_info_changed
 154         {
 155             void * unused;
 156         } input_item_info_changed;
 157         struct input_item_error_when_reading_changed
 158         {
 159             bool new_value;
 160         } input_item_error_when_reading_changed;
 161         struct input_item_preparse_ended
 162         {
 163             int new_status;
 164         } input_item_preparse_ended;
 165     } u;
 166 } vlc_event_t;
 167
 168 /* Event callback type */
 169 typedef void ( *vlc_event_callback_t )( const vlc_event_t *, void * );
 170
 171  /*****************************************************************************
 172  * Event manager
 173  *****************************************************************************/
 174
 175 /*
 176  * p_obj points to the object that owns the event manager, and from
 177  * which events are sent
 178  */
 179 void vlc_event_manager_init( vlc_event_manager_t * p_em, void * p_obj );
 180
 181 /*
 182  * Destroy
 183  */
 184 void vlc_event_manager_fini( vlc_event_manager_t * p_em );
 185
 186 /*
 187  * Send an event to the listener attached to this p_em.
 188  */
 189 void vlc_event_send( vlc_event_manager_t * p_em, vlc_event_t * );
 190
 191 /*
 192  * Add a callback for an event.
 193  */
 194 VLC_API int vlc_event_attach( vlc_event_manager_t * p_event_manager,
 195                               vlc_event_type_t event_type,
 196                               vlc_event_callback_t pf_callback,
 197                               void *p_user_data );
 198
 199 /*
 200  * Remove a callback for an event.
 201  */
 202 VLC_API void vlc_event_detach( vlc_event_manager_t *p_event_manager,
 203                                vlc_event_type_t event_type,
 204                                vlc_event_callback_t pf_callback,
 205                                void *p_user_data );
 206
 207 #endif /* VLC_EVENTS_H */