From 865bb365ed2cc1b49a88424c8f117a25c8d2af0b Mon Sep 17 00:00:00 2001
From: James Turner <zakalawe@mac.com>
Date: Fri, 18 Dec 2015 21:42:22 -0800
Subject: [PATCH] Trying to bullet-proof the traffic code.

---
 src/ATC/GroundController.cxx   |  5 ++++
 src/Airports/groundnetwork.cxx |  5 +++-
 src/Traffic/Schedule.cxx       | 48 +++++++++++++++++++++++++++++-----
 src/Traffic/Schedule.hxx       |  4 +--
 4 files changed, 53 insertions(+), 9 deletions(-)

diff --git a/src/ATC/GroundController.cxx b/src/ATC/GroundController.cxx
index 23bb001a3..d238b44c3 100644
--- a/src/ATC/GroundController.cxx
+++ b/src/ATC/GroundController.cxx
@@ -107,6 +107,11 @@ void FGGroundController::announcePosition(int id,
                                        double radius, int leg,
                                        FGAIAircraft * aircraft)
 {
+    if (!aircraft || !aircraft->getPerformance()) {
+        SG_LOG(SG_ATC, SG_ALERT, "announcePosition: missing aircraft performance");
+        return;
+    }
+
     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
diff --git a/src/Airports/groundnetwork.cxx b/src/Airports/groundnetwork.cxx
index 5a0705d9f..98d8ec113 100644
--- a/src/Airports/groundnetwork.cxx
+++ b/src/Airports/groundnetwork.cxx
@@ -57,7 +57,10 @@ FGTaxiSegment::FGTaxiSegment(FGTaxiNode* aStart, FGTaxiNode* aEnd) :
   index(0),
   oppositeDirection(0)
 {
-};
+    if (!aStart || !aEnd) {
+        throw sg_exception("Missing node arguments creating FGTaxiSegment");
+    }
+}
 
 SGGeod FGTaxiSegment::getCenter() const
 {
diff --git a/src/Traffic/Schedule.cxx b/src/Traffic/Schedule.cxx
index 7e8cdbdfc..691a34ea6 100644
--- a/src/Traffic/Schedule.cxx
+++ b/src/Traffic/Schedule.cxx
@@ -505,17 +505,53 @@ bool FGAISchedule::next()
    return true;
 }
 
-time_t FGAISchedule::getDepartureTime() { return (*flights.begin())->getDepartureTime   (); }
+time_t FGAISchedule::getDepartureTime()
+{
+    if (flights.empty())
+        return 0;
+
+    return (*flights.begin())->getDepartureTime   ();
+}
+
+FGAirport *FGAISchedule::getDepartureAirport()
+{
+    if (flights.empty())
+        return 0;
+
+    return (*flights.begin())->getDepartureAirport();
+}
+
+FGAirport *FGAISchedule::getArrivalAirport()
+{
+    if (flights.empty())
+        return 0;
 
-FGAirport *FGAISchedule::getDepartureAirport() { return (*flights.begin())->getDepartureAirport(); }
+    return (*flights.begin())->getArrivalAirport  ();
+}
 
-FGAirport *FGAISchedule::getArrivalAirport() { return (*flights.begin())->getArrivalAirport  (); }
+int FGAISchedule::getCruiseAlt()
+{
+    if (flights.empty())
+        return 0;
 
-int FGAISchedule::getCruiseAlt() { return (*flights.begin())->getCruiseAlt       (); }
+    return (*flights.begin())->getCruiseAlt       ();
+}
 
-const std::string &FGAISchedule::getCallSign() { return (*flights.begin())->getCallSign (); }
+std::string FGAISchedule::getCallSign()
+{
+    if (flights.empty())
+        return std::string();
 
-const std::string &FGAISchedule::getFlightRules() { return (*flights.begin())->getFlightRules (); }
+    return (*flights.begin())->getCallSign ();
+}
+
+std::string FGAISchedule::getFlightRules()
+{
+    if (flights.empty())
+        return std::string();
+
+    return (*flights.begin())->getFlightRules ();
+}
 
 FGScheduledFlight* FGAISchedule::findAvailableFlight (const string &currentDestination,
                                                       const string &req,
diff --git a/src/Traffic/Schedule.hxx b/src/Traffic/Schedule.hxx
index 12169f4b7..5d7a360c1 100644
--- a/src/Traffic/Schedule.hxx
+++ b/src/Traffic/Schedule.hxx
@@ -118,9 +118,9 @@ class FGAISchedule
   const std::string& getFlightType     () { return flightType;};
   const std::string& getAirline        () { return airline; };
   const std::string& getAircraft       () { return acType; };
-  const std::string& getCallSign       ();
+  std::string getCallSign       ();
   const std::string& getRegistration   () { return registration;};
-  const std::string& getFlightRules    ();
+  std::string getFlightRules    ();
   bool getHeavy                   () { return heavy; };
   double getCourse                () { return courseToDest; };
   unsigned int getRunCount        () { return runCount; };
-- 
2.39.5