Cosmetic
[vlc.git] / src / misc / events.c
1 /*****************************************************************************
2  * events.c: events interface
3  * This library provides an interface to the send and receive events.
4  * It is more lightweight than variable based callback.
5  *****************************************************************************
6  * Copyright (C) 1998-2005 the VideoLAN team
7  * $Id$
8  *
9  * Authors: Pierre d'Herbemont <pdherbemont # videolan.org >
10  *
11  * This program is free software; you can redistribute it and/or modify
12  * it under the terms of the GNU General Public License as published by
13  * the Free Software Foundation; either version 2 of the License, or
14  * (at your option) any later version.
15  *
16  * This program is distributed in the hope that it will be useful,
17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
19  * GNU General Public License for more details.
20  *
21  * You should have received a copy of the GNU General Public License
22  * along with this program; if not, write to the Free Software
23  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
24  *****************************************************************************/
25
26 /*****************************************************************************
27  * Preamble
28  *****************************************************************************/
29
30 #ifdef HAVE_CONFIG_H
31 # include "config.h"
32 #endif
33
34 #include <vlc_common.h>
35
36 #include <assert.h>
37
38 #include <vlc_events.h>
39 #include <vlc_arrays.h>
40
41 /*****************************************************************************
42  * Documentation : Read vlc_events.h
43  *****************************************************************************/
44
45 //#define DEBUG_EVENT
46
47 /*****************************************************************************
48  *  Private types.
49  *****************************************************************************/
50
51 typedef struct vlc_event_listener_t
52 {
53     void *               p_user_data;
54     vlc_event_callback_t pf_callback;
55 #ifdef DEBUG_EVENT
56     char *               psz_debug_name;
57 #endif
58 } vlc_event_listener_t;
59
60 typedef struct vlc_event_listeners_group_t
61 {
62     vlc_event_type_t    event_type;
63     DECL_ARRAY(struct vlc_event_listener_t *) listeners;
64
65    /* Used in vlc_event_send() to make sure to behave
66       Correctly when vlc_event_detach was called during
67       a callback */
68     bool          b_sublistener_removed;
69                                          
70 } vlc_event_listeners_group_t;
71
72 #ifdef DEBUG_EVENT
73 static const char ppsz_event_type_to_name[][40] =
74 {
75     [vlc_InputStateChanged]             = "vlc_InputStateChanged",
76     [vlc_InputSelectedStreamChanged]    = "vlc_InputSelectedStreamChanged",
77
78     [vlc_InputItemMetaChanged]          = "vlc_InputItemMetaChanged",
79     [vlc_InputItemSubItemAdded]         = "vlc_InputItemSubItemAdded",
80     [vlc_InputItemDurationChanged]      = "vlc_InputItemDurationChanged",
81     [vlc_InputItemPreparsedChanged]     = "vlc_InputItemPreparsedChanged",
82     [vlc_InputItemNameChanged]          = "vlc_InputItemNameChanged",
83     [vlc_InputItemInfoChanged]          = "vlc_InputItemInfoChanged",
84     [vlc_InputItemErrorWhenReadingChanged] = "vlc_InputItemErrorWhenReadingChanged",
85
86     [vlc_ServicesDiscoveryItemAdded]    = "vlc_ServicesDiscoveryItemAdded",
87     [vlc_ServicesDiscoveryItemRemoved]  = "vlc_ServicesDiscoveryItemRemoved",
88     [vlc_ServicesDiscoveryStarted]      = "vlc_ServicesDiscoveryStarted",
89     [vlc_ServicesDiscoveryEnded]        = "vlc_ServicesDiscoveryEnded"
90 };
91 #endif
92
93 static bool
94 listeners_are_equal( vlc_event_listener_t * listener1,
95                      vlc_event_listener_t * listener2 )
96 {
97     return listener1->pf_callback == listener2->pf_callback &&
98            listener1->p_user_data == listener2->p_user_data;
99 }
100
101 static bool
102 group_contains_listener( vlc_event_listeners_group_t * group,
103                          vlc_event_listener_t * searched_listener )
104 {
105     vlc_event_listener_t * listener;
106     FOREACH_ARRAY( listener, group->listeners )
107         if( listeners_are_equal(searched_listener, listener) )
108             return true;
109     FOREACH_END()
110     return false;
111 }
112
113 /*****************************************************************************
114  *
115  *****************************************************************************/
116
117 /**
118  * Initialize event manager object
119  * p_obj is the object that contains the event manager. But not
120  * necessarily a vlc_object_t (an input_item_t is not a vlc_object_t
121  * for instance).
122  * p_parent_obj gives a libvlc instance
123  */
124 int __vlc_event_manager_init( vlc_event_manager_t * p_em, void * p_obj,
125                               vlc_object_t * p_parent_obj )
126 {
127     p_em->p_obj = p_obj;
128     p_em->p_parent_object = p_parent_obj;
129     vlc_mutex_init( &p_em->object_lock );
130
131     /* We need a recursive lock here, because we need to be able
132      * to call libvlc_event_detach even if vlc_event_send is in
133      * the call frame.
134      * This ensures that after libvlc_event_detach, the callback
135      * will never gets triggered.
136      * */
137     vlc_mutex_init_recursive( &p_em->event_sending_lock );
138     ARRAY_INIT( p_em->listeners_groups );
139     return VLC_SUCCESS;
140 }
141
142 /**
143  * Destroy the event manager
144  */
145 void vlc_event_manager_fini( vlc_event_manager_t * p_em )
146 {
147     struct vlc_event_listeners_group_t * listeners_group;
148     struct vlc_event_listener_t * listener;
149
150     vlc_mutex_destroy( &p_em->object_lock );
151     vlc_mutex_destroy( &p_em->event_sending_lock );
152
153     FOREACH_ARRAY( listeners_group, p_em->listeners_groups )
154         FOREACH_ARRAY( listener, listeners_group->listeners )
155             free( listener );
156         FOREACH_END()
157         ARRAY_RESET( listeners_group->listeners );
158         free( listeners_group );
159     FOREACH_END()
160     ARRAY_RESET( p_em->listeners_groups );
161 }
162
163 /**
164  * Destroy the event manager
165  */
166 int vlc_event_manager_register_event_type(
167         vlc_event_manager_t * p_em,
168         vlc_event_type_t event_type )
169 {
170     vlc_event_listeners_group_t * listeners_group;
171     listeners_group = malloc(sizeof(vlc_event_listeners_group_t));
172
173     if( !listeners_group )
174         return VLC_ENOMEM;
175
176     listeners_group->event_type = event_type;
177     ARRAY_INIT( listeners_group->listeners );
178  
179     vlc_mutex_lock( &p_em->object_lock );
180     ARRAY_APPEND( p_em->listeners_groups, listeners_group );
181     vlc_mutex_unlock( &p_em->object_lock );
182
183     return VLC_SUCCESS;
184 }
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,
190                      vlc_event_t * p_event )
191 {
192     vlc_event_listeners_group_t * listeners_group = NULL;
193     vlc_event_listener_t * listener;
194     vlc_event_listener_t * array_of_cached_listeners = NULL;
195     vlc_event_listener_t * cached_listener;
196     int i, i_cached_listeners = 0;
197
198     /* Fill event with the sending object now */
199     p_event->p_obj = p_em->p_obj;
200
201     vlc_mutex_lock( &p_em->object_lock );
202     FOREACH_ARRAY( listeners_group, p_em->listeners_groups )
203         if( listeners_group->event_type == p_event->type )
204         {
205             if( listeners_group->listeners.i_size <= 0 )
206                 break;
207
208             /* Save the function to call */
209             i_cached_listeners = listeners_group->listeners.i_size;
210             array_of_cached_listeners = malloc(
211                     sizeof(vlc_event_listener_t)*i_cached_listeners );
212             if( !array_of_cached_listeners )
213             {
214                 vlc_mutex_unlock( &p_em->object_lock );
215                 return;
216             }
217
218             cached_listener = array_of_cached_listeners;
219             FOREACH_ARRAY( listener, listeners_group->listeners )
220                 memcpy( cached_listener, listener, sizeof(vlc_event_listener_t));
221 #ifdef DEBUG_EVENT
222                 cached_listener->psz_debug_name = strdup(cached_listener->psz_debug_name);
223 #endif
224                 cached_listener++;
225             FOREACH_END()
226
227             break;
228         }
229     FOREACH_END()
230     vlc_mutex_unlock( &p_em->object_lock );
231  
232     /* Call the function attached */
233     cached_listener = array_of_cached_listeners;
234
235     if( !listeners_group || !array_of_cached_listeners )
236     {
237         free( array_of_cached_listeners );
238         return;
239     }
240
241     vlc_mutex_lock( &p_em->event_sending_lock ) ;
242
243     /* Track item removed from *this* thread, with a simple flag */
244     listeners_group->b_sublistener_removed = false;
245
246     for( i = 0; i < i_cached_listeners; i++ )
247     {
248 #ifdef DEBUG_EVENT
249         msg_Dbg( p_em->p_parent_object,
250                     "Calling '%s' with a '%s' event (data %p)",
251                     cached_listener->psz_debug_name,
252                     ppsz_event_type_to_name[p_event->type],
253                     cached_listener->p_user_data );
254         free(cached_listener->psz_debug_name);
255 #endif
256         /* No need to lock on listeners_group, a listener group can't be removed */
257         if( listeners_group->b_sublistener_removed )
258         {
259             /* If a callback was removed, this gets called */
260             bool valid_listener;
261             vlc_mutex_lock( &p_em->object_lock );
262             valid_listener = group_contains_listener( listeners_group, cached_listener );
263             vlc_mutex_unlock( &p_em->object_lock );
264             if( !valid_listener )
265             {
266 #ifdef DEBUG_EVENT
267                 msg_Dbg( p_em->p_parent_object, "Callback was removed during execution" );
268 #endif
269                 cached_listener++;
270                 continue;
271             }
272         }
273         cached_listener->pf_callback( p_event, cached_listener->p_user_data );
274         cached_listener++;
275     }
276     vlc_mutex_unlock( &p_em->event_sending_lock );
277
278     free( array_of_cached_listeners );
279 }
280
281 /**
282  * Add a callback for an event.
283  */
284 int __vlc_event_attach( vlc_event_manager_t * p_em,
285                         vlc_event_type_t event_type,
286                         vlc_event_callback_t pf_callback,
287                         void *p_user_data,
288                         const char * psz_debug_name )
289 {
290     vlc_event_listeners_group_t * listeners_group;
291     vlc_event_listener_t * listener;
292     listener = malloc(sizeof(vlc_event_listener_t));
293     if( !listener )
294         return VLC_ENOMEM;
295  
296     listener->p_user_data = p_user_data;
297     listener->pf_callback = pf_callback;
298 #ifdef DEBUG_EVENT
299     listener->psz_debug_name = strdup( psz_debug_name );
300 #else
301     (void)psz_debug_name;
302 #endif
303
304     vlc_mutex_lock( &p_em->object_lock );
305     FOREACH_ARRAY( listeners_group, p_em->listeners_groups )
306         if( listeners_group->event_type == event_type )
307         {
308             ARRAY_APPEND( listeners_group->listeners, listener );
309 #ifdef DEBUG_EVENT
310                 msg_Dbg( p_em->p_parent_object,
311                     "Listening to '%s' event with '%s' (data %p)",
312                     ppsz_event_type_to_name[event_type],
313                     listener->psz_debug_name,
314                     listener->p_user_data );
315 #endif
316             vlc_mutex_unlock( &p_em->object_lock );
317             return VLC_SUCCESS;
318         }
319     FOREACH_END()
320     vlc_mutex_unlock( &p_em->object_lock );
321
322     msg_Err( p_em->p_parent_object, "cannot attach to an object event" );
323     free(listener);
324     return VLC_EGENERIC;
325 }
326
327 /**
328  * Remove a callback for an event.
329  */
330
331 int vlc_event_detach( vlc_event_manager_t *p_em,
332                       vlc_event_type_t event_type,
333                       vlc_event_callback_t pf_callback,
334                       void *p_user_data )
335 {
336     vlc_event_listeners_group_t * listeners_group;
337     struct vlc_event_listener_t * listener;
338
339     vlc_mutex_lock( &p_em->object_lock );
340     vlc_mutex_lock( &p_em->event_sending_lock );
341     FOREACH_ARRAY( listeners_group, p_em->listeners_groups )
342         if( listeners_group->event_type == event_type )
343         {
344             FOREACH_ARRAY( listener, listeners_group->listeners )
345                 if( listener->pf_callback == pf_callback &&
346                     listener->p_user_data == p_user_data )
347                 {
348                     /* Tell vlc_event_send, we did remove an item from that group,
349                        in case vlc_event_send is in our caller stack  */
350                     listeners_group->b_sublistener_removed = true;
351
352                     /* that's our listener */
353                     ARRAY_REMOVE( listeners_group->listeners,
354                         fe_idx /* This comes from the macro (and that's why
355                                   I hate macro) */ );
356 #ifdef DEBUG_EVENT
357                     msg_Dbg( p_em->p_parent_object,
358                         "Detaching '%s' from '%s' event (data %p)",
359                         listener->psz_debug_name,
360                         ppsz_event_type_to_name[event_type],
361                         listener->p_user_data );
362
363                     free( listener->psz_debug_name );
364 #endif
365                     free( listener );
366                     vlc_mutex_unlock( &p_em->event_sending_lock );
367                     vlc_mutex_unlock( &p_em->object_lock );
368                     return VLC_SUCCESS;
369                 }
370             FOREACH_END()
371         }
372     FOREACH_END()
373     vlc_mutex_unlock( &p_em->event_sending_lock );
374     vlc_mutex_unlock( &p_em->object_lock );
375
376     msg_Warn( p_em->p_parent_object, "cannot detach from an object event" );
377
378     return VLC_EGENERIC;
379 }
380