DRTVWR-476: Infrastructure to help manage long-lived coroutines.

Introduce LLCoros::Stop exception, with subclasses Stopping, Stopped and
Shutdown. Add LLCoros::checkStop(), intended to be called periodically by any
coroutine with nontrivial lifespan. It checks the LLApp status and, unless
isRunning(), throws one of these new exceptions.

Make LLCoros::toplevel() catch Stop specially and log forcible coroutine
termination.

Now that LLApp status matters even in a test program, introduce a trivial
LLTestApp subclass whose sole function is to make isRunning() true.
(LLApp::setStatus() is protected: only a subclass can call it.) Add LLTestApp
instances to lleventcoro_test.cpp and lllogin_test.cpp.

Make LLCoros::toplevel() accept parameters by value rather than by const
reference so we can continue using them even after context switches.

Make private LLCoros::get_CoroData() static. Given that we've observed some
coroutines living past LLCoros destruction, making the caller call
LLCoros::instance() is more dangerous than encapsulating it within a static
method -- since the encapsulated call can check LLCoros::wasDeleted() first
and do something reasonable instead. This also eliminates the need for both a
const and non-const overload.

Defend LLCoros::delete_CoroData() (cleanup function for fiber_specific_ptr for
CoroData, implicitly called after coroutine termination) against calls after
~LLCoros().

Add a status string to coroutine-local data, with LLCoro::setStatus(),
getStatus() and RAII class TempStatus.

Add an optional 'when' string argument to LLCoros::printActiveCoroutines().
Make ~LLCoros() print the coroutines still active at destruction.

1 files changed, 34 insertions, 0 deletions

diff --git a/indra/test/lltestapp.h b/indra/test/lltestapp.h
new file mode 100644
index 0000000000..382516cd2b
--- /dev/null
+++ b/indra/test/lltestapp.h
@@ -0,0 +1,34 @@
+/**
+ * @file   lltestapp.h
+ * @author Nat Goodspeed
+ * @date   2019-10-21
+ * @brief  LLApp subclass useful for testing.
+ * 
+ * $LicenseInfo:firstyear=2019&license=viewerlgpl$
+ * Copyright (c) 2019, Linden Research, Inc.
+ * $/LicenseInfo$
+ */
+
+#if ! defined(LL_LLTESTAPP_H)
+#define LL_LLTESTAPP_H
+
+#include "llapp.h"
+
+/**
+ * LLTestApp is a dummy LLApp that simply sets LLApp::isRunning() for anyone
+ * who cares.
+ */
+class LLTestApp: public LLApp
+{
+public:
+    LLTestApp()
+    {
+        setStatus(APP_STATUS_RUNNING);
+    }
+
+    bool init()    { return true; }
+    bool cleanup() { return true; }
+    bool frame()   { return true; }
+};
+
+#endif /* ! defined(LL_LLTESTAPP_H) */