diff options
Diffstat (limited to 'libs/pbd/event_loop.cc')
-rw-r--r-- | libs/pbd/event_loop.cc | 27 |
1 files changed, 24 insertions, 3 deletions
diff --git a/libs/pbd/event_loop.cc b/libs/pbd/event_loop.cc index 5a9a220075..5c132037d3 100644 --- a/libs/pbd/event_loop.cc +++ b/libs/pbd/event_loop.cc @@ -20,14 +20,35 @@ EventLoop::set_event_loop_for_thread (EventLoop* loop) thread_event_loop.set (loop, do_not_delete_the_loop_pointer); } -/** Called when a sigc::trackable that was connected to using the invalidator() macro - * is destroyed. - */ void* EventLoop::invalidate_request (void* data) { InvalidationRecord* ir = (InvalidationRecord*) data; + /* Some of the requests queued with an EventLoop may involve functors + * that make method calls to objects whose lifetime is shorter + * than the EventLoop's. We do not want to make those calls if the + * object involve has been destroyed. To prevent this, we + * provide a way to invalidate those requests when the object is + * destroyed. + * + * An object was passed to __invalidator() which added a callback to + * EventLoop::invalidate_request() to its "notify when destroyed" + * list. __invalidator() returned an InvalidationRecord that has been + * to passed to this function as data. + * + * The object is currently being destroyed and so we want to + * mark all requests involving this object that are queued with + * any EventLoop as invalid. + * + * As of April 2012, we are usign sigc::trackable as the base object + * used to queue calls to ::invalidate_request() to be made upon + * destruction, via its ::add_destroy_notify_callback() API. This is + * not necessarily ideal, but it is very close to precisely what we + * want, and many of the objects we want to do this with already + * inherit (indirectly) from sigc::trackable. + */ + if (ir->event_loop) { Glib::Mutex::Lock lm (ir->event_loop->slot_invalidation_mutex()); for (list<BaseRequestObject*>::iterator i = ir->requests.begin(); i != ir->requests.end(); ++i) { |