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_InputItemSubItemTreeAdded,
 102     vlc_InputItemDurationChanged,
 103     vlc_InputItemPreparsedChanged,
 104     vlc_InputItemNameChanged,
 105     vlc_InputItemInfoChanged,
 106     vlc_InputItemErrorWhenReadingChanged,
 107     vlc_InputItemPreparseEnded,
 108 } vlc_event_type_t;
 109
 110 typedef struct vlc_event_listeners_group_t
 111 {
 112     DECL_ARRAY(struct vlc_event_listener_t *) listeners;
 113 } vlc_event_listeners_group_t;
 114
 115 /* Event manager type */
 116 typedef struct vlc_event_manager_t
 117 {
 118     void * p_obj;
 119     vlc_mutex_t lock;
 120     vlc_event_listeners_group_t events[vlc_InputItemPreparseEnded + 1];
 121 } vlc_event_manager_t;
 122
 123 /* Event definition */
 124 typedef struct vlc_event_t
 125 {
 126     vlc_event_type_t type;
 127     void * p_obj; /* Sender object, automatically filled by vlc_event_send() */
 128     union vlc_event_type_specific
 129     {
 130         /* Input item events */
 131         struct vlc_input_item_meta_changed
 132         {
 133             vlc_meta_type_t meta_type;
 134         } input_item_meta_changed;
 135         struct vlc_input_item_subitem_added
 136         {
 137             input_item_t * p_new_child;
 138         } input_item_subitem_added;
 139         struct vlc_input_item_subitem_tree_added
 140         {
 141             input_item_node_t * p_root;
 142         } input_item_subitem_tree_added;
 143         struct vlc_input_item_duration_changed
 144         {
 145             mtime_t new_duration;
 146         } input_item_duration_changed;
 147         struct vlc_input_item_preparsed_changed
 148         {
 149             int new_status;
 150         } input_item_preparsed_changed;
 151         struct vlc_input_item_name_changed
 152         {
 153             const char * new_name;
 154         } input_item_name_changed;
 155         struct vlc_input_item_info_changed
 156         {
 157             void * unused;
 158         } input_item_info_changed;
 159         struct input_item_error_when_reading_changed
 160         {
 161             bool new_value;
 162         } input_item_error_when_reading_changed;
 163         struct input_item_preparse_ended
 164         {
 165             int new_status;
 166         } input_item_preparse_ended;
 167     } u;
 168 } vlc_event_t;
 169
 170 /* Event callback type */
 171 typedef void ( *vlc_event_callback_t )( const vlc_event_t *, void * );
 172
 173  /*****************************************************************************
 174  * Event manager
 175  *****************************************************************************/
 176
 177 /*
 178  * p_obj points to the object that owns the event manager, and from
 179  * which events are sent
 180  */
 181 void vlc_event_manager_init( vlc_event_manager_t * p_em, void * p_obj );
 182
 183 /*
 184  * Destroy
 185  */
 186 void vlc_event_manager_fini( vlc_event_manager_t * p_em );
 187
 188 /*
 189  * Send an event to the listener attached to this p_em.
 190  */
 191 void vlc_event_send( vlc_event_manager_t * p_em, vlc_event_t * );
 192
 193 /*
 194  * Add a callback for an event.
 195  */
 196 VLC_API int vlc_event_attach( vlc_event_manager_t * p_event_manager,
 197                               vlc_event_type_t event_type,
 198                               vlc_event_callback_t pf_callback,
 199                               void *p_user_data );
 200
 201 /*
 202  * Remove a callback for an event.
 203  */
 204 VLC_API void vlc_event_detach( vlc_event_manager_t *p_event_manager,
 205                                vlc_event_type_t event_type,
 206                                vlc_event_callback_t pf_callback,
 207                                void *p_user_data );
 208
 209 #endif /* VLC_EVENTS_H */