misc/events.c: Fix event sending, by properly supporting event_manager edition (event...

[vlc] / src / misc / events.c

diff --git a/src/misc/events.c b/src/misc/events.c
index 6e056f7ff777880b57095e83b48164b23b8c948d..67ffb3fee56bcbfa506a052e926d149807b446b7 100644 (file)
--- a/src/misc/events.c
+++ b/src/misc/events.c
@@ -58,6 +58,12 @@ typedef struct vlc_event_listeners_group_t
 {
     vlc_event_type_t    event_type;
     DECL_ARRAY(struct vlc_event_listener_t *) listeners;
+
+   /* Used in vlc_event_send() to make sure to behave
+      Correctly when vlc_event_detach was called during
+      a callback */
+    vlc_bool_t          b_sublistener_removed;
+                                         
 } vlc_event_listeners_group_t;
 
 #ifdef DEBUG_EVENT
@@ -70,6 +76,18 @@ static const char * ppsz_event_type_to_name[] =
 };
 #endif
 
+static vlc_bool_t
+group_contains_listener( vlc_event_listeners_group_t * group,
+                         vlc_event_listener_t * searched_listener )
+{
+    vlc_event_listener_t * listener;
+    FOREACH_ARRAY( listener, group->listeners )
+        if( searched_listener == listener )
+            return VLC_TRUE;
+    FOREACH_END()
+    return VLC_FALSE;
+}
+
 /*****************************************************************************
  *
  *****************************************************************************/
@@ -87,6 +105,14 @@ int vlc_event_manager_init( vlc_event_manager_t * p_em, void * p_obj,
     p_em->p_obj = p_obj;
     p_em->p_parent_object = p_parent_obj;
     vlc_mutex_init( p_parent_obj, &p_em->object_lock );
+
+    /* We need a recursive lock here, because we need to be able
+     * to call libvlc_event_detach even if vlc_event_send is in
+     * the call frame.
+     * This ensures that after libvlc_event_detach, the callback
+     * will never gets triggered.
+     * */
+    vlc_mutex_init_recursive( p_parent_obj, &p_em->event_sending_lock );
     ARRAY_INIT( p_em->listeners_groups );
     return VLC_SUCCESS;
 }
@@ -100,6 +126,7 @@ void vlc_event_manager_fini( vlc_event_manager_t * p_em )
     struct vlc_event_listener_t * listener;
 
     vlc_mutex_destroy( &p_em->object_lock );
+    vlc_mutex_destroy( &p_em->event_sending_lock );
 
     FOREACH_ARRAY( listeners_group, p_em->listeners_groups )
         FOREACH_ARRAY( listener, listeners_group->listeners )
@@ -183,6 +210,11 @@ void vlc_event_send( vlc_event_manager_t * p_em,
  
     /* Call the function attached */
     cached_listener = array_of_cached_listeners;
+    vlc_mutex_lock( &p_em->event_sending_lock );
+
+    /* Track item removed from *this* thread, with a simple flag */
+    listeners_group->b_sublistener_removed = VLC_FALSE;
+
     for( i = 0; i < i_cached_listeners; i++ )
     {
 #ifdef DEBUG_EVENT
@@ -193,12 +225,29 @@ void vlc_event_send( vlc_event_manager_t * p_em,
                     cached_listener->p_user_data );
         free(cached_listener->psz_debug_name);
 #endif
-
+        /* No need to lock on listeners_group, a listener group can't be removed */
+        if( listeners_group->b_sublistener_removed )
+        {
+            /* If a callback was removed, this gets called */
+            vlc_bool_t valid_listener;
+            vlc_mutex_lock( &p_em->object_lock );
+            valid_listener = group_contains_listener( listeners_group, cached_listener );
+            vlc_mutex_unlock( &p_em->object_lock );
+            if( !valid_listener )
+            {
+#ifdef DEBUG_EVENT
+                msg_Dbg( p_em->p_parent_object, "Callback was removed during execution" );
+#endif
+                cached_listener++;
+                continue;
+            }
+        }
         cached_listener->pf_callback( p_event, cached_listener->p_user_data );
         cached_listener++;
     }
-    free( array_of_cached_listeners );
+    vlc_mutex_unlock( &p_em->event_sending_lock );
 
+    free( array_of_cached_listeners );
 }
 
 /**
@@ -250,6 +299,7 @@ int __vlc_event_attach( vlc_event_manager_t * p_em,
 /**
  * Remove a callback for an event.
  */
+
 int vlc_event_detach( vlc_event_manager_t *p_em,
                       vlc_event_type_t event_type,
                       vlc_event_callback_t pf_callback,
@@ -259,6 +309,7 @@ int vlc_event_detach( vlc_event_manager_t *p_em,
     struct vlc_event_listener_t * listener;
 
     vlc_mutex_lock( &p_em->object_lock );
+    vlc_mutex_lock( &p_em->event_sending_lock );
     FOREACH_ARRAY( listeners_group, p_em->listeners_groups )
         if( listeners_group->event_type == event_type )
         {
@@ -266,6 +317,10 @@ int vlc_event_detach( vlc_event_manager_t *p_em,
                 if( listener->pf_callback == pf_callback &&
                     listener->p_user_data == p_user_data )
                 {
+                    /* Tell vlc_event_send, we did remove an item from that group,
+                       in case vlc_event_send is in our caller stack  */
+                    listeners_group->b_sublistener_removed = VLC_TRUE;
+
                     /* that's our listener */
                     ARRAY_REMOVE( listeners_group->listeners,
                         fe_idx /* This comes from the macro (and that's why
@@ -280,15 +335,18 @@ int vlc_event_detach( vlc_event_manager_t *p_em,
                     free( listener->psz_debug_name );
 #endif
                     free( listener );
+                    vlc_mutex_unlock( &p_em->event_sending_lock );
                     vlc_mutex_unlock( &p_em->object_lock );
                     return VLC_SUCCESS;
                 }
             FOREACH_END()
         }
     FOREACH_END()
+    vlc_mutex_unlock( &p_em->event_sending_lock );
     vlc_mutex_unlock( &p_em->object_lock );
 
     msg_Warn( p_em->p_parent_object, "Can't detach to an object event manager event" );
 
     return VLC_EGENERIC;
 }
+