vlc_events.h 5.17 KB
Newer Older
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172
/*****************************************************************************
 * events.h: events definitions
 * Interface used to send events.
 *****************************************************************************
 * Copyright (C) 2007 the VideoLAN team
 * $Id$
 *
 * Authors: Pierre d'Herbemont
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
 *****************************************************************************/

#ifndef VLC_EVENTS_H
# define VLC_EVENTS_H

#include <vlc_arrays.h>

/**
 * \file
 * This file is the interface definition for events
 * (implementation in src/misc/events.c)
 */

/*****************************************************************************
 * Documentation
 *****************************************************************************/
/*
 **** Background
 *
 * This implements a way to send and receive event for an object (which can be
 * a simple C struct or less).
 * 
 * This is in direct concurrency with the Variable based Callback
 * (see src/misc/variables.c).
 *
 * It has the following advantages over Variable based Callback:
 * - No need to implement the whole VLC_COMMON_MEMBERS in the object,
 * thus it reduce it size. This is especially true for input_item_t which
 * doesn't have VLC_COMMON_MEMBERS. This is the first reason of existence of
 * this implementation.
 * - Libvlc can easily be based upon that.
 * - Existing event are clearly declared (in include/vlc_events.h)
 *
 *
 **** Example usage
 *
 * (vlc_cool_object_t doesn't need to have the VLC_COMMON_MEMBERS.)
 *
 * struct vlc_cool_object_t 
 * {
 *        ...
 *        vlc_event_manager_t p_event_manager;
 *        ...
 * }
 *
 * vlc_my_cool_object_new()
 * {
 *        ...
 *        vlc_event_manager_Create( &p_self->p_event_manager, p_this );
 *        vlc_event_manager_register_event_type(p_self->p_event_manager,
 *                vlc_MyCoolObjectDidSomething, p_e)
 *        ...
 * }
 *
 * vlc_my_cool_object_release()
 * {
 *         ...
 *         vlc_event_manager_release( p_self->p_event_manager );
 *         ...
 * }
 *
 * vlc_my_cool_object_do_something()
 * {
 *        ...
 *        vlc_event_t event;
 *        event.type = vlc_MyCoolObjectDidSomething;
 *        event.u.my_cool_object_did_something.what_it_did = kSomething;
 *        vlc_event_send( p_self->p_event_manager, &event );
 * }
 * */
 
  /*****************************************************************************
 * Event Type
 *****************************************************************************/

/* Private structure defined in misc/events.c */
struct vlc_event_listeners_group_t;

/* Event manager type */
typedef struct vlc_event_manager_t
{
    void * p_obj;
    DECL_ARRAY(struct vlc_event_listeners_group_t *) listeners_groups;
} vlc_event_manager_t;

/* List of event */
typedef enum vlc_event_type_t {
    vlc_InputItemMetaChanged
} vlc_event_type_t;

/* Event definition */
typedef struct vlc_event_t
{
    vlc_event_type_t type;
    void * p_obj; /* Sender object, automatically filled by event_Send() */
    union event_type_specific
    {
        struct
        {
            int meta; /* One of the meta identified in include/vlc_meta.h */
        } input_item_meta_changed;
    } u;
} vlc_event_t;

/* Event callback type */
typedef void ( *vlc_event_callback_t )( const vlc_event_t *, void * );

 /*****************************************************************************
 * Event manager
 *****************************************************************************/

/*
 * p_obj points to the object that owns the event manager, and from
 * which events are sent
 */
int event_manager_Create( vlc_event_manager_t * p_em, void * p_obj );

/*
 * Destroy
 */
void event_manager_Destroy( vlc_event_manager_t * p_em );

/*
 * Tells a specific event manager that it will handle event_type object
 */
int event_manager_RegisterEventType( vlc_event_manager_t * p_em,
                                     vlc_event_type_t event_type );

/*
 * Send an event to the listener attached to this p_em.
 */
void event_Send( vlc_event_manager_t * p_em, vlc_event_t * p_event );

/*
 * Add a callback for an event.
 */
int event_Attach( vlc_event_manager_t * p_event_manager,
                  vlc_event_type_t event_type,
                  vlc_event_callback_t pf_callback,
                  void *p_user_data );

/*
 * Remove a callback for an event.
 */
int event_Detach( vlc_event_manager_t *p_event_manager,
                   vlc_event_type_t event_type,
                   vlc_event_callback_t pf_callback,
                   void *p_user_data );

#endif /* VLC_EVENTS_H */