fix event loop timing issue

The event loop tries to run no faster than every 10ms. If it detects
that it goes faster, it would incorrectly calculate the difference, and
then wait (what I assume was) way too long or too short.
Either way, now it's fixed and it correctly works, even when introducing
new lua states.

src/Common.cpp

@@ -25,6 +25,7 @@ void Application::RegisterShutdownHandler(const TShutdownHandler& Handler) {
 }
 
 void Application::GracefullyShutdown() {
+    SetShutdown(true);
     static bool AlreadyShuttingDown = false;
     static uint8_t ShutdownAttempts = 0;
     if (AlreadyShuttingDown) {
@@ -93,6 +94,22 @@ bool Application::IsOutdated(const Version& Current, const Version& Newest) {
     }
 }
 
+bool Application::IsShuttingDown() {
+    std::shared_lock Lock(mShutdownMtx);
+    return mShutdown;
+}
+
+void Application::SleepSafeSeconds(size_t Seconds) {
+    // Sleeps for 500 ms, checks if a shutdown occurred, and so forth
+    for (size_t i = 0; i < Seconds * 2; ++i) {
+        if (Application::IsShuttingDown()) {
+            return;
+        } else {
+            std::this_thread::sleep_for(std::chrono::milliseconds(500));
+        }
+    }
+}
+
 TEST_CASE("Application::IsOutdated (version check)") {
     SUBCASE("Same version") {
         CHECK(!Application::IsOutdated({ 1, 2, 3 }, { 1, 2, 3 }));
@@ -158,6 +175,11 @@ void Application::SetSubsystemStatus(const std::string& Subsystem, Status status
     mSystemStatusMap[Subsystem] = status;
 }
 
+void Application::SetShutdown(bool Val) {
+    std::unique_lock Lock(mShutdownMtx);
+    mShutdown = Val;
+}
+
 TEST_CASE("Application::SetSubsystemStatus") {
     Application::SetSubsystemStatus("Test", Application::Status::Good);
     auto Map = Application::GetSubsystemStatuses();