DEV-43463: Keep LLEventPump's LLStandardSignal alive during post()

Replace LLEventPump's boost::scoped_ptr<LLStandardSignal> with
boost::shared_ptr. Take a local stack copy of that shared_ptr in post()
methods, and invoke the signal through that copy. This guards against scenario
in which LLEventPump gets destroyed during signal invocation. (See Jira for
details.) Re-enable Mani's test case that used to crash.
Introduce ll_template_cast<> to allow a template function to recognize a
parameter of a particular type.
Introduce LLListenerWrapper mechanism to support wrapper objects for
LLEventPump listeners. You instantiate an LLListenerWrapper subclass object
inline in the listen() call (typically with llwrap<>), passing it the real
listener, trusting it to forward the eventual call.
Introduce prototypical LLCoutListener and LLLogListener subclasses for
illustrative and diagnostic purposes. Test that LLLogListener doesn't block
recognizing LLEventTrackable base class bound into wrapped listener.

1 files changed, 29 insertions, 1 deletions

diff --git a/indra/test/llevents_tut.cpp b/indra/test/llevents_tut.cpp
index 31130c3c79..e58b10ce07 100644
--- a/indra/test/llevents_tut.cpp
+++ b/indra/test/llevents_tut.cpp
@@ -21,6 +21,7 @@
 #define testable public
 #include "llevents.h"
 #undef testable
+#include "lllistenerwrapper.h"
 // STL headers
 // std headers
 #include <iostream>
@@ -639,6 +640,33 @@ namespace tut
         heaptest.post(2);
     }
 
+    template<> template<>
+    void events_object::test<15>()
+    {
+        // This test ensures that using an LLListenerWrapper subclass doesn't
+        // block Boost.Signals2 from recognizing a bound LLEventTrackable
+        // subclass.
+        set_test_name("listen(llwrap<LLLogListener>(boost::bind(...TempTrackableListener ref...)))");
+        bool live = false;
+        LLEventPump& heaptest(pumps.obtain("heaptest"));
+        LLBoundListener connection;
+        {
+            TempTrackableListener tempListener("temp", live);
+            ensure("TempTrackableListener constructed", live);
+            connection = heaptest.listen(tempListener.getName(),
+                                         llwrap<LLLogListener>(
+                                         boost::bind(&TempTrackableListener::call,
+                                                     boost::ref(tempListener), _1)));
+            heaptest.post(1);
+            check_listener("received", tempListener, 1);
+        } // presumably this will make tempListener go away?
+        // verify that
+        ensure("TempTrackableListener destroyed", ! live);
+        ensure("implicit disconnect", ! connection.connected());
+        // now just make sure we don't blow up trying to access a freed object!
+        heaptest.post(2);
+    }
+
     class TempSharedListener: public TempListener,
                               public boost::enable_shared_from_this<TempSharedListener>
     {
@@ -649,7 +677,7 @@ namespace tut
     };
 
     template<> template<>
-    void events_object::test<15>()
+    void events_object::test<16>()
     {
         set_test_name("listen(boost::bind(...TempSharedListener ref...))");
 #if 0