Fix crash disabling AI traffic at runtime.

https://sourceforge.net/p/flightgear/codetickets/1848/

src/AIModel/AIManager.cxx

@@ -182,6 +182,9 @@ FGAIManager::shutdown()
     unloadAllScenarios();
     
     BOOST_FOREACH(FGAIBase* ai, ai_list) {
+        // other subsystems, especially ATC, may have references. This
+        // lets them detect if the AI object should be skipped
+        ai->setDie(true);
         ai->unbind();
     }
     

src/ATC/GroundController.cxx

@@ -116,7 +116,7 @@ void FGGroundController::announcePosition(int id,
     TrafficVectorIterator i = activeTraffic.begin();
     // Search search if the current id alread has an entry
     // This might be faster using a map instead of a vector, but let's start by taking a safe route
-    if (activeTraffic.size()) {
+    if (!activeTraffic.empty()) {
         //while ((i->getId() != id) && i != activeTraffic.end()) {
         while (i != activeTraffic.end()) {
             if (i->getId() == id) {
@@ -126,7 +126,7 @@ void FGGroundController::announcePosition(int id,
         }
     }
     // Add a new TrafficRecord if no one exsists for this aircraft.
-    if (i == activeTraffic.end() || (activeTraffic.size() == 0)) {
+    if (i == activeTraffic.end() || (activeTraffic.empty())) {
         FGTrafficRecord rec;
         rec.setId(id);
         rec.setLeg(leg);
@@ -973,6 +973,9 @@ void FGGroundController::update(double dt)
     for (i = activeTraffic.begin(); i != activeTraffic.end(); i++) {
         updateActiveTraffic(i, priority, now);
     }
+
+    eraseDeadTraffic(startupTraffic);
+    eraseDeadTraffic(activeTraffic);
 }
 
 void FGGroundController::updateStartupTraffic(TrafficVectorIterator i,
@@ -1044,18 +1047,23 @@ void FGGroundController::updateStartupTraffic(TrafficVectorIterator i,
     }
 }
 
-void FGGroundController::updateActiveTraffic(TrafficVectorIterator i,
+bool FGGroundController::updateActiveTraffic(TrafficVectorIterator i,
                                              int& priority,
                                              time_t now)
 {
     if (!i->getAircraft()) {
         SG_LOG(SG_ATC, SG_ALERT, "updateActiveTraffic: missing aircraft");
-        return;
+        return false;
+    }
+
+    if (i->getAircraft()->getDie()) {
+        // aircraft has died
+        return false;
     }
 
     if (!i->getAircraft()->getPerformance()) {
         SG_LOG(SG_ATC, SG_ALERT, "updateActiveTraffic: missing aircraft performance");
-        return;
+        return false;
     }
 
     double length = 0;
@@ -1064,7 +1072,7 @@ void FGGroundController::updateActiveTraffic(TrafficVectorIterator i,
 
     if (!network) {
         SG_LOG(SG_ATC, SG_ALERT, "updateActiveTraffic: missing ground network");
-        return;
+        return false;
     }
 
     i->setPriority(priority++);
@@ -1097,4 +1105,6 @@ void FGGroundController::updateActiveTraffic(TrafficVectorIterator i,
             network->blockSegmentsEndingAt(seg, i->getId(), blockTime - 30, now);
         }
     }
+
+    return true;
 }

src/ATC/GroundController.hxx

@@ -59,7 +59,7 @@ private:
 
 
     void updateStartupTraffic(TrafficVectorIterator i, int& priority, time_t now);
-    void updateActiveTraffic(TrafficVectorIterator i, int& priority, time_t now);
+    bool updateActiveTraffic(TrafficVectorIterator i, int& priority, time_t now);
 public:
     FGGroundController();
     ~FGGroundController();

src/ATC/trafficcontrol.cxx

@@ -459,6 +459,10 @@ bool FGTrafficRecord::isOpposing(FGGroundNetwork * net,
 
 bool FGTrafficRecord::isActive(int margin) const
 {
+    if (aircraft->getDie()) {
+        return false;
+    }
+    
     time_t now = globals->get_time_params()->get_cur_time();
     time_t deptime = aircraft->getTrafficRef()->getDepartureTime();
     return ((now + margin) > deptime);
@@ -839,6 +843,26 @@ void FGATCController::init()
     }
 }
 
+class AircraftIsDead
+{
+public:
+    bool operator()(const FGTrafficRecord& traffic) const
+    {
+        if (!traffic.getAircraft()) {
+            return true;
+        }
+
+        return traffic.getAircraft()->getDie();
+    }
+};
+
+void FGATCController::eraseDeadTraffic(TrafficVector& vec)
+{
+    TrafficVector::iterator it = std::remove_if(vec.begin(), vec.end(), AircraftIsDead());
+    vec.erase(it, vec.end());
+}
+
+
 /***************************************************************************
  * class FGTowerController
  *
@@ -1108,7 +1132,7 @@ string FGTowerController::getName() {
 
 void FGTowerController::update(double dt)
 {
-
+    eraseDeadTraffic(activeTraffic);
 }
 
 
@@ -1572,7 +1596,7 @@ string FGStartupController::getName() {
 
 void FGStartupController::update(double dt)
 {
-
+    eraseDeadTraffic(activeTraffic);
 }
 
 
@@ -1706,11 +1730,9 @@ void FGApproachController::signOff(int id)
 
 void FGApproachController::update(double dt)
 {
-
+    eraseDeadTraffic(activeTraffic);
 }
 
-
-
 bool FGApproachController::hasInstruction(int id)
 {
     TrafficVectorIterator i = activeTraffic.begin();

src/ATC/trafficcontrol.hxx

@@ -387,6 +387,7 @@ protected:
     std::string genTransponderCode(const std::string& fltRules);
     bool isUserAircraft(FGAIAircraft*);
 
+    void eraseDeadTraffic(TrafficVector& vec);
 public:
     typedef enum {
         MSG_ANNOUNCE_ENGINE_START,