Add timers.lua API module and test_timers.lua test program.

Since timers presents a timers.Timer Lua class supporting queries and
cancellation, make TimersListener::scheduleAfter() and scheduleEvery() respond
immediately so the newly constructed Timer object has the reqid necessary to
perform those subsequent operations.

This requires that Lua invocations of these operations avoid calling the
caller's callback with that initial response.

Reinvent leap.generate() to return a Lua object supporting next() and done()
methods. A plain Lua coroutine that (indirectly) calls fiber.wait() confuses
the fiber scheduler, so avoid implementing generate() as a Lua coroutine.

Add a bit more leap.lua diagnostic output.

1 files changed, 10 insertions, 4 deletions

diff --git a/indra/llcommon/llcallbacklist.cpp b/indra/llcommon/llcallbacklist.cpp
index 59ff8d3759..9f324b2fe9 100644
--- a/indra/llcommon/llcallbacklist.cpp
+++ b/indra/llcommon/llcallbacklist.cpp
@@ -410,11 +410,14 @@ private:
 
 void TimersListener::scheduleAfter(const LLSD& params)
 {
+    // Timer creation functions respond immediately with the reqid of the
+    // created timer, as well as later when the timer fires. That lets the
+    // requester invoke cancel, isRunning or timeUntilCall.
+    Response response(LLSD(), params);
     LLSD::Real after{ params["after"] };
     if (after < MINTIMER)
     {
-        sendReply(llsd::map("error", stringize("after must be at least ", MINTIMER)), params);
-        return;
+        return response.error(stringize("after must be at least ", MINTIMER));
     }
 
     mHandles.emplace(
@@ -432,11 +435,14 @@ void TimersListener::scheduleAfter(const LLSD& params)
 
 void TimersListener::scheduleEvery(const LLSD& params)
 {
+    // Timer creation functions respond immediately with the reqid of the
+    // created timer, as well as later when the timer fires. That lets the
+    // requester invoke cancel, isRunning or timeUntilCall.
+    Response response(LLSD(), params);
     LLSD::Real every{ params["every"] };
     if (every < MINTIMER)
     {
-        sendReply(llsd::map("error", stringize("every must be at least ", MINTIMER)), params);
-        return;
+        return response.error(stringize("every must be at least ", MINTIMER));
     }
 
     mHandles.emplace(