From f2f0fa7fd0efc221f1358dd4e440b5d51a5fb8b4 Mon Sep 17 00:00:00 2001 From: Nat Goodspeed Date: Thu, 18 Jul 2024 13:29:34 -0400 Subject: Ditch `LLEventTrackable` aka `boost::signals2::trackable`. Remove documented `LLEventPump` support for `LLEventTrackable`. That claimed support was always a little bit magical/fragile. IF: * a class included `LLEventTrackable` as a base class AND * an instance of that class was managed by `boost::shared_ptr` AND * you passed one of that class's methods and the `boost::shared_ptr` specifically to `boost::bind()` AND * the resulting `boost::bind()` object was passed into `LLEventPump::listen()` THEN the promise was that on destruction of that object, that listener would automatically be disconnected -- instead of leaving a dangling pointer bound into the `LLEventPump`, causing a crash on the next `LLEventPump::post()` call. The only existing code in the viewer code base that exercised `LLEventTrackable` functionality was in test programs. When the viewer calls `LLEventPump::listen()`, it typically stores the resulting connection object in an `LLTempBoundListener` variable, which guarantees disconnection on destruction of that variable. The fact that `LLEventTrackable` support is specific to `boost::bind()`, that it silently fails to keep its promise with `std::bind()` or a lambda or any other form of C++ callable, makes it untrustworthy for new code. Note that the code base still uses `boost::signals2::trackable` for other `boost::signals2::signal` instances not associated with `LLEventPump`. We are not changing those at this time. --- indra/llui/llnotifications.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'indra/llui/llnotifications.h') diff --git a/indra/llui/llnotifications.h b/indra/llui/llnotifications.h index ab4f009a80..206c521592 100644 --- a/indra/llui/llnotifications.h +++ b/indra/llui/llnotifications.h @@ -734,7 +734,7 @@ typedef std::multimap LLNotificationMap; // all of the built-in tests should attach to the "Visible" channel // class LLNotificationChannelBase : - public LLEventTrackable, + public boost::signals2::trackable, public LLRefCount { LOG_CLASS(LLNotificationChannelBase); -- cgit v1.2.3