Check if SimConnect was properly loaded before attempting to use it

This commit adds a check that loadAndResolveSimConnect actually succeeds and
moves it right before SimConnect_Open is called.
The method itself was improved to check whether symbols got loaded already
in a previous run, before doing everything again.

src/plugins/simulator/fsxcommon/simconnectsymbols.cpp

@@ -99,6 +99,9 @@ QString getLastErrorMsg()
 
 bool loadAndResolveSimConnect(bool manifestProbing)
 {
+    // Check if already loaded
+    if (gSymbols.SimConnect_Open) { return true; }
+
     QLibrary simConnectDll;
     simConnectDll.setFileName("SimConnect.dll");
     simConnectDll.setLoadHints(QLibrary::PreventUnloadHint);
@@ -171,6 +174,11 @@ bool loadAndResolveSimConnect(bool manifestProbing)
         gSymbols.SimConnect_CreateClientData = reinterpret_cast<PfnSimConnect_CreateClientData>(simConnectDll.resolve("SimConnect_CreateClientData"));
         gSymbols.SimConnect_AddToClientDataDefinition = reinterpret_cast<PfnSimConnect_AddToClientDataDefinition>(simConnectDll.resolve("SimConnect_AddToClientDataDefinition"));
     }
+    else
+    {
+        CLogMessage(static_cast<SimConnectSymbols*>(nullptr)).error("Failed to load SimConnect.dll: %1") << getLastErrorMsg();
+        return false;
+    }
 
     return true;
 }

src/plugins/simulator/fsxcommon/simulatorfsxcommon.cpp

@@ -87,6 +87,9 @@ namespace BlackSimPlugin
         {
             if (this->isConnected()) { return true; }
             this->reset();
+
+            if (!loadAndResolveSimConnect(true)) { return false; }
+
             if (FAILED(SimConnect_Open(&m_hSimConnect, sApp->swiftVersionChar(), nullptr, 0, 0, 0)))
             {
                 // reset state as expected for unconnected
@@ -2017,7 +2020,6 @@ namespace BlackSimPlugin
             constexpr int QueryInterval = 5 * 1000; // 5 seconds
             m_timer.setInterval(QueryInterval);
             m_timer.setObjectName(this->objectName().append(":m_timer"));
-            loadAndResolveSimConnect(true);
             connect(&m_timer, &QTimer::timeout, this, &CSimulatorFsxCommonListener::checkConnection);
         }
 
@@ -2027,6 +2029,9 @@ namespace BlackSimPlugin
             m_simConnectVersion.clear();
             m_simulatorName.clear();
             m_simulatorDetails.clear();
+
+            if (!loadAndResolveSimConnect(true)) { return; }
+
             m_timer.start();
         }