smo::Mind instance now global; track & manage JOLT state in Mind

We moved the instance of smo::Mind to global scope. I suppose we'll
only support one instance of Mind per SMO process at least for now.

We now track the state of Mind threads' JOLT-waiting. This allows us
to centralize the Mind thread shutdown logic. Mind::finalizeReq()
now takes care of all Mind thread shutdown state logic by tracking
whether Mind threads need to be JOLTed first before being told to
exit.

smocore/mind.cpp

@@ -4,6 +4,8 @@
 
 namespace smo {
 
+Mind mind;
+
 void Mind::initialize()
 {
     /* Distribute threads across available CPUs */
@@ -20,8 +22,9 @@ void Mind::initialize()
 
     /* Jolt the threads, then start them */
     ComponentThread::joltAllMindThreadsReq(
-        []()
+        [this]()
         {
+            this->threadsHaveBeenJolted = true;
             std::cout << "Mrntt: All mind threads JOLTed." << "\n";
             ComponentThread::startAllMindThreadsReq(
                 []()
@@ -33,8 +36,38 @@ void Mind::initialize()
     );
 }
 
-void Mind::finalize(void)
+void Mind::finalizeReq(std::function<void()> callback)
 {
+    /* If the threads haven't been jolted, we need to do that first, because
+     * otherwise they'll just enter their main loops and wait for control
+     * messages from mrntt after processing the exit request.
+     */
+    if (!threadsHaveBeenJolted)
+    {
+        ComponentThread::joltAllMindThreadsReq(
+            [this, callback]()
+            {
+                this->threadsHaveBeenJolted = true;
+                ComponentThread::exitAllMindThreadsReq(
+                    [callback]()
+                    {
+                        std::cout << "Mrntt: All mind threads exited." << "\n";
+                        if (callback) { callback(); }
+                    }
+                );
+            }
+        );
+    }
+    else
+    {
+        ComponentThread::exitAllMindThreadsReq(
+            [callback]()
+            {
+                std::cout << "Mrntt: All mind threads exited." << "\n";
+                if (callback) { callback(); }
+            }
+        );
+    }
 }
 
 } // namespace smo