SL-16220: Add tests for WorkQueue::waitForResult(), void & non-void.

indra/llcommon/tests/workqueue_test.cpp

@@ -20,7 +20,10 @@
 // external library headers
 // other Linden headers
 #include "../test/lltut.h"
+#include "../test/catch_and_store_what_in.h"
 #include "llcond.h"
+#include "llcoros.h"
+#include "lleventcoro.h"
 #include "llstring.h"
 #include "stringize.h"
 
@@ -177,4 +180,50 @@ namespace tut
         main.runOne();
         ensure_equals("failed to run both lambdas", observe, "queue;main");
     }
+
+    template<> template<>
+    void object::test<6>()
+    {
+        set_test_name("waitForResult");
+        std::string stored;
+        // Try to call waitForResult() on this thread's main coroutine. It
+        // should throw because the main coroutine must service the queue.
+        auto what{ catch_what<WorkQueue::Error>(
+                [this, &stored](){ stored = queue.waitForResult(
+                        [](){ return "should throw"; }); }) };
+        ensure("lambda should not have run", stored.empty());
+        ensure_not("waitForResult() should have thrown", what.empty());
+        ensure(STRINGIZE("should mention waitForResult: " << what),
+               what.find("waitForResult") != std::string::npos);
+
+        // Call waitForResult() on a coroutine, with a string result.
+        LLCoros::instance().launch(
+            "waitForResult string",
+            [this, &stored]()
+            { stored = queue.waitForResult(
+                    [](){ return "string result"; }); });
+        llcoro::suspend();
+        // Nothing will have happened yet because, even if the coroutine did
+        // run immediately, all it did was to queue the inner lambda on
+        // 'queue'. Service it.
+        queue.runOne();
+        llcoro::suspend();
+        ensure_equals("bad waitForResult return", stored, "string result");
+
+        // Call waitForResult() on a coroutine, with a void callable.
+        stored.clear();
+        bool done = false;
+        LLCoros::instance().launch(
+            "waitForResult void",
+            [this, &stored, &done]()
+            {
+                queue.waitForResult([&stored](){ stored = "ran"; });
+                done = true;
+            });
+        llcoro::suspend();
+        queue.runOne();
+        llcoro::suspend();
+        ensure_equals("didn't run coroutine", stored, "ran");
+        ensure("void waitForResult() didn't return", done);
+    }
 } // namespace tut

indra/llcommon/workqueue.h

@@ -92,6 +92,25 @@ namespace LL
             post(TimePoint::clock::now(), std::move(callable));
         }
 
+        /**
+         * Post work to be run at a specified time to another WorkQueue, which
+         * may or may not still exist and be open. Return true if we were able
+         * to post.
+         */
+        template <typename CALLABLE>
+        static bool postMaybe(weak_t target, const TimePoint& time, CALLABLE&& callable);
+
+        /**
+         * Post work to another WorkQueue, which may or may not still exist
+         * and be open. Return true if we were able to post.
+         */
+        template <typename CALLABLE>
+        static bool postMaybe(weak_t target, CALLABLE&& callable)
+        {
+            return postMaybe(target, TimePoint::clock::now(),
+                             std::forward<CALLABLE>(callable));
+        }
+
         /**
          * Launch a callable returning bool that will trigger repeatedly at
          * specified interval, until the callable returns false.
@@ -136,25 +155,6 @@ namespace LL
                           std::move(callable), std::move(callback));
         }
 
-        /**
-         * Post work to be run at a specified time to another WorkQueue, which
-         * may or may not still exist and be open. Return true if we were able
-         * to post.
-         */
-        template <typename CALLABLE>
-        static bool postMaybe(weak_t target, const TimePoint& time, CALLABLE&& callable);
-
-        /**
-         * Post work to another WorkQueue, which may or may not still exist
-         * and be open. Return true if we were able to post.
-         */
-        template <typename CALLABLE>
-        static bool postMaybe(weak_t target, CALLABLE&& callable)
-        {
-            return postMaybe(target, TimePoint::clock::now(),
-                             std::forward<CALLABLE>(callable));
-        }
-
         /**
          * Post work to another WorkQueue to be run at a specified time,
          * blocking the calling coroutine until then, returning the result to