[ion] Events::Journal has isEmpty

ion/include/ion/events.h

@@ -57,6 +57,7 @@ class Journal {
 public:
   virtual void pushEvent(Event e) = 0;
   virtual Event popEvent() = 0;
+  virtual bool isEmpty() = 0;
 };
 
 void replayFrom(Journal * l);

ion/src/shared/events_keyboard.cpp

@@ -125,11 +125,10 @@ void logTo(Journal * l) { sDestinationJournal = l; }
 
 Event getEvent(int * timeout) {
   if (sSourceJournal != nullptr) {
-    Event e = sSourceJournal->popEvent();
-    if (e == None) {
+    if (sSourceJournal->isEmpty()) {
       sSourceJournal = nullptr;
     } else {
-      return e;
+      return sSourceJournal->popEvent();
     }
   }
   Event e = innerGetEvent(timeout);

ion/src/simulator/shared/journal.cpp

@@ -12,10 +12,16 @@ public:
     m_eventStorage.push(e);
   }
   virtual Event popEvent() override {
+    if (isEmpty()) {
+      return Ion::Events::None;
+    }
     Event e = m_eventStorage.front();
     m_eventStorage.pop();
     return e;
   }
+  virtual bool isEmpty() override {
+    return m_eventStorage.empty();
+  }
 private:
   std::queue<Event> m_eventStorage;
 };