dbus: don't lock the playlist, but only yield the input to prevent its...

dbus: don't lock the playlist, but only yield the input to prevent its destruction while we are accessing it.
We do that because we can't lock the playlist when we're in the input "state" callback because we MAY have been called by playlist_Control(), which does lock the playlist, and then call us.
ref #1346

modules/control/dbus.c

@@ -113,17 +113,19 @@ DBUS_METHOD( PositionGet )
     dbus_int32_t i_pos;
 
     playlist_t *p_playlist = pl_Yield( ((vlc_object_t*) p_this) );
-    PL_LOCK;
+
     input_thread_t *p_input = p_playlist->p_input;
 
     if( !p_input )
         i_pos = 0;
     else
     {
+        vlc_object_yield( p_input );
         var_Get( p_input, "time", &position );
+        vlc_object_release( p_input );
         i_pos = position.i_time / 1000;
     }
-    PL_UNLOCK;
+
     pl_Release( ((vlc_object_t*) p_this) );
     ADD_INT32( &i_pos );
     REPLY_SEND;
@@ -152,15 +154,17 @@ DBUS_METHOD( PositionSet )
         return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
     }
     p_playlist = pl_Yield( ((vlc_object_t*) p_this) );
-    PL_LOCK;
+
     input_thread_t *p_input = p_playlist->p_input;
 
     if( p_input )
     {
         position.i_time = i_pos * 1000;
+        vlc_object_yield( p_input );
         var_Set( p_input, "time", position );
+        vlc_object_release( p_input );
     }
-    PL_UNLOCK;
+
     pl_Release( ((vlc_object_t*) p_this) );
     REPLY_SEND;
 }
@@ -816,7 +820,7 @@ static int TrackChange( vlc_object_t *p_this, const char *psz_var,
     p_sys->b_meta_read = VLC_FALSE;
 
     p_playlist = pl_Yield( p_intf );
-    PL_LOCK;
+
     p_input = p_playlist->p_input;
 
     if( !p_input )
@@ -827,7 +831,7 @@ static int TrackChange( vlc_object_t *p_this, const char *psz_var,
     }
 
     vlc_object_yield( p_input );
-    PL_UNLOCK;
+
     pl_Release( p_playlist );
 
     p_item = input_GetItem( p_input );
@@ -943,12 +947,13 @@ static int MarshalStatus( intf_thread_t* p_intf, DBusMessageIter* args )
     input_thread_t* p_input = NULL;
 
     p_playlist = pl_Yield( (vlc_object_t*) p_intf );
-    PL_LOCK;
     p_input = p_playlist->p_input;
 
     i_state = 2;
     if( p_input )
     {
+        vlc_object_yield( p_input );
+
         var_Get( p_input, "state", &val );
         if( val.i_int >= END_S )
             i_state = 2;
@@ -956,6 +961,8 @@ static int MarshalStatus( intf_thread_t* p_intf, DBusMessageIter* args )
             i_state = 1;
         else if( val.i_int <= PLAYING_S )
             i_state = 0;
+
+        vlc_object_release( p_input );
     }
 
     var_Get( p_playlist, "random", &val );
@@ -967,7 +974,6 @@ static int MarshalStatus( intf_thread_t* p_intf, DBusMessageIter* args )
     var_Get( p_playlist, "loop", &val );
     i_loop = val.i_int;
 
-    PL_UNLOCK;
     pl_Release( p_playlist );
 
     dbus_message_iter_open_container( args, DBUS_TYPE_STRUCT, NULL, &status );