Thread Calculation : fix data race.

Common/Header/Globals.h

@@ -71,7 +71,6 @@ struct Radio_t {
 };
 
 GEXTERN bool MenuActive GEXTFALSE;
-GEXTERN Poco::Event dataTriggerEvent;
 
 GEXTERN unsigned short HaveSystemInfo GEXTZERO; // Normally only on linux
 GEXTERN bool HaveBatteryInfo GEXTFALSE;

Common/Source/Thread_Calculation.cpp

@@ -22,9 +22,7 @@ extern bool OnFastPanning;
 // PulseEvent is unreliable. But it does not matter anymore, since we should
 // change approach for compatibility with unix.
 
-void TriggerRedraws(NMEA_INFO *nmea_info, DERIVED_INFO *derived_info) {
-    (void) nmea_info;
-    (void) derived_info;
+void TriggerRedraws() {
 
 #ifndef ENABLE_OPENGL
     if (MapWindow::IsDisplayRunning()) {
@@ -42,119 +40,122 @@ void TriggerRedraws(NMEA_INFO *nmea_info, DERIVED_INFO *derived_info) {
 #endif
 }
 
-// System boot specific flags
-// Give me a go/no-go
-static bool goCalculationThread = false;
-
 class CalculationThread : public Thread {
 public:
     CalculationThread() : Thread("Calculation") {}
 
     void Run() override {
-        bool needcalculationsslow = false;
-
-        // let's not create a deadlock here, setting the go after another race condition
-        goCalculationThread = true; // 091119 CHECK
         // wait for proper startup signal
         while (!MapWindow::IsDisplayRunning()) {
             Sleep(100);
         }
 
-        Sleep(1000); // 091213  BUGFIX need to syncronize !!! TOFIX02 TODO
-
-        while (!MapWindow::CLOSETHREAD) {
+        Sleep(1000); // 091213  BUGFIX need to synchronize !!! TOFIX02 TODO
 
-            if (dataTriggerEvent.tryWait(5000)) dataTriggerEvent.reset();
-            if (MapWindow::CLOSETHREAD) break; // drop out on exit
+        while (Wait()) {
 
 #ifdef HAVE_CPU_FREQUENCY
             const ScopeLockCPU cpu;
 #endif
             // make local copy before editing...
-            LockFlightData();
-            FLARM_RefreshSlots(&GPS_INFO);
-            Fanet_RefreshSlots(&GPS_INFO); //refresh slots of FANET
-            memcpy(&tmpGPS, &GPS_INFO, sizeof (NMEA_INFO));
-            memcpy(&tmpCALCULATED, &CALCULATED_INFO, sizeof (DERIVED_INFO));
-            UnlockFlightData();
-
-            DoCalculationsVario(&tmpGPS, &tmpCALCULATED);
-            if (!VarioAvailable(tmpGPS)) {
+            UpdateLocalFlightData();
+
+            DoCalculationsVario(&Local_NMEA, &Local_DERIVED);
+            if (!VarioAvailable(Local_NMEA)) {
                 TriggerVarioUpdate(); // emulate vario update
             }
 
-            if (DoCalculations(&tmpGPS, &tmpCALCULATED)) {
-#if (WINDOWSPC>0) && !TESTBENCH
-#else
-                if (!INPAN)
-#endif
-                {
+            bool needcalculationsslow = false;
+
+            if (DoCalculations(&Local_NMEA, &Local_DERIVED)) {
+                if (!INPAN) {
                     MapWindow::MapDirty = true;
                 }
                 needcalculationsslow = true;
 
-                if (tmpCALCULATED.Circling)
+                if (Local_DERIVED.Circling) {
                     MapWindow::mode.Fly(MapWindow::Mode::MODE_FLY_CIRCLING);
-                else if (tmpCALCULATED.FinalGlide)
+                }
+                else if (Local_DERIVED.FinalGlide) {
                     MapWindow::mode.Fly(MapWindow::Mode::MODE_FLY_FINAL_GLIDE);
-                else
+                }
+                else {
                     MapWindow::mode.Fly(MapWindow::Mode::MODE_FLY_CRUISE);
+                }
             }
 
-            if (MapWindow::CLOSETHREAD) break; // drop out on exit
-
             // values changed, so copy them back now: ONLY CALCULATED INFO
             // should be changed in DoCalculations, so we only need to write
             // that one back (otherwise we may write over new data)
-            // Need to be Done before TriggerRedraw            
-            LockFlightData();
-            memcpy(&CALCULATED_INFO, &tmpCALCULATED, sizeof (DERIVED_INFO));
-            UnlockFlightData();            
+            // Need to be Done before TriggerRedraw
+            UpdateCalculatedFlightData();
 
             // This is activating another run for Thread Draw
-            TriggerRedraws(&tmpGPS, &tmpCALCULATED);
+            TriggerRedraws();
 
-            if (MapWindow::CLOSETHREAD) break; // drop out on exit
+            if (needcalculationsslow || (SIMMODE && ReplayLogger::IsEnabled())) {
+                DoCalculationsSlow(&Local_NMEA, &Local_DERIVED);
+                needcalculationsslow = false;
 
-            bool need_update = false;
-            if (SIMMODE) {
-                if (needcalculationsslow || (ReplayLogger::IsEnabled())) {
-                    DoCalculationsSlow(&tmpGPS, &tmpCALCULATED);
-                    needcalculationsslow = false;
-                    need_update = true;
-                }
-            } else {
-                if (needcalculationsslow) {
-                    DoCalculationsSlow(&tmpGPS, &tmpCALCULATED);
-                    needcalculationsslow = false;
-                    need_update = true;
-                }
-            }
-
-            if(need_update) {
                 // CALCULATED_INFO need to copy back second time if data are updated by DoCalculationsSlow;
-                LockFlightData();
-                memcpy(&CALCULATED_INFO, &tmpCALCULATED, sizeof (DERIVED_INFO));
-                UnlockFlightData();            
-            }            
-
-            if (MapWindow::CLOSETHREAD) break; // drop out on exit
+                UpdateCalculatedFlightData();
+            }
 
             // update live tracker with new values
             // this is a nonblocking call, live tracker runs on different thread
-            tracking::Update(tmpGPS, tmpCALCULATED);
+            tracking::Update(Local_NMEA, Local_DERIVED);
 
-            UpdateFlightDataRecorder(tmpGPS, tmpCALCULATED);
-            CheckAltitudeAlarms(tmpGPS, tmpCALCULATED);
+            UpdateFlightDataRecorder(Local_NMEA, Local_DERIVED);
+            CheckAltitudeAlarms(Local_NMEA, Local_DERIVED);
 
             ExternalDeviceSendTarget();
-            SendDataToExternalDevice(tmpGPS, tmpCALCULATED);
+            SendDataToExternalDevice(Local_NMEA, Local_DERIVED);
         }
     }
 
+    void SignalNewData() {
+        ScopeLock lock(mtx);
+        new_data = true;
+        cond.Signal();
+    }
+
+    void RequestStop() {
+        ScopeLock lock(mtx);
+        run = false;
+        cond.Signal();
+    }
+
 private:
-    NMEA_INFO tmpGPS;
-    DERIVED_INFO tmpCALCULATED;
+
+    void UpdateLocalFlightData() {
+        ScopeLock lock(CritSec_FlightData);
+        FLARM_RefreshSlots(&GPS_INFO);
+        Fanet_RefreshSlots(&GPS_INFO); //refresh slots of FANET
+        Local_NMEA = GPS_INFO;
+        Local_DERIVED = CALCULATED_INFO;
+    }
+
+    void UpdateCalculatedFlightData() {
+        ScopeLock lock(CritSec_FlightData);
+        CALCULATED_INFO = Local_DERIVED;
+    }
+
+    bool Wait() {
+        ScopeLock lock(mtx);
+        while (run && !new_data) {
+            cond.Wait(mtx);
+        }
+        new_data = false;
+        return run;
+    }
+
+    NMEA_INFO Local_NMEA;
+    DERIVED_INFO Local_DERIVED;
+
+    Mutex mtx;
+    Cond cond;
+    bool run = true;
+    bool new_data = false;
 };
 
 CalculationThread _CalculationThread;
@@ -165,12 +166,16 @@ CalculationThread _CalculationThread;
 void CreateCalculationThread() {
     // Create a read thread for performing calculations
     _CalculationThread.Start();
-
-    while(!(goCalculationThread)) {
-        Sleep(50);
-    }
 }
 
 void WaitThreadCalculation() {
     _CalculationThread.Join();
 }
+
+void StopThreadCalculation() {
+    _CalculationThread.RequestStop();
+}
+
+void TriggerGPSUpdate() {
+    _CalculationThread.SignalNewData();
+}

Common/Source/Utils.cpp

@@ -18,10 +18,6 @@ int GetUTCOffset() {
     return UTCOffset;
 }
 
-void TriggerGPSUpdate() {
-    dataTriggerEvent.set();
-}
-
 // This is currently doing nothing.
 
 void TriggerVarioUpdate() {

Common/Source/Window/WndMain.cpp

@@ -47,6 +47,7 @@ WndMain::~WndMain() {
 }
 
 extern void WaitThreadCalculation();
+extern void StopThreadCalculation();
 
 void BeforeShutdown(void) {
 
@@ -110,7 +111,7 @@ void BeforeShutdown(void) {
   MapWindow::CloseDrawingThread();
 
   // Stop calculating too (wake up)
-  dataTriggerEvent.set();
+  StopThreadCalculation();
 
   // Clear data
   // LKTOKEN _@M1222_ "Shutdown, saving task..."