From 4bbff581f3da6879b4509ef1046975f630656fcf Mon Sep 17 00:00:00 2001
From: James Turner <zakalawe@mac.com>
Date: Fri, 23 Oct 2020 15:40:16 +0100
Subject: [PATCH] Fix crash in flight-plan UI

Sentry-Id: FLIGHTGEAR-ES
---
 src/GUI/RouteDiagram.cxx  | 11 ++++++++++-
 src/Navaids/routePath.cxx | 10 ++++++++++
 2 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/src/GUI/RouteDiagram.cxx b/src/GUI/RouteDiagram.cxx
index 1af9fb875..e46e6716e 100644
--- a/src/GUI/RouteDiagram.cxx
+++ b/src/GUI/RouteDiagram.cxx
@@ -48,6 +48,8 @@ void RouteDiagram::setFlightplan(FlightPlanController *fp)
     }
 
     m_flightplan = fp;
+    m_activeLegIndex = 0;
+
     emit flightplanChanged(fp);
 
     if (fp) {
@@ -76,6 +78,11 @@ void RouteDiagram::setActiveLegIndex(int activeLegIndex)
     if (m_activeLegIndex == activeLegIndex)
         return;
 
+    if ((activeLegIndex < 0) || (activeLegIndex >= numLegs())) {
+        qWarning() << Q_FUNC_INFO << "invalid leg index" << activeLegIndex;
+        return;
+    }
+
     m_activeLegIndex = activeLegIndex;
     emit legIndexChanged(m_activeLegIndex);
 
@@ -132,7 +139,9 @@ void RouteDiagram::fpChanged()
 {
     FlightPlanRef fp = m_flightplan->flightplan();
     m_path.reset(new RoutePath(fp));
-    if (fp) {
+    m_activeLegIndex = 0;
+
+    if (fp && (fp->numLegs() > 0)) {
         const double halfLegDistance = m_path->distanceForIndex(m_activeLegIndex) * 0.5;
         m_projectionCenter = m_path->positionForDistanceFrom(m_activeLegIndex, halfLegDistance);
     }
diff --git a/src/Navaids/routePath.cxx b/src/Navaids/routePath.cxx
index 82ee9961b..3fc2c0e13 100644
--- a/src/Navaids/routePath.cxx
+++ b/src/Navaids/routePath.cxx
@@ -1153,6 +1153,11 @@ double RoutePath::distanceForVia(Via* via, int index) const
 
 double RoutePath::trackForIndex(int index) const
 {
+    const auto sz = static_cast<int>(d->waypoints.size());
+    if ((index < 0) || (index >= sz)) {
+        return 0.0;
+    }
+
     if (d->waypoints[index].skipped)
         return trackForIndex(index - 1);
 
@@ -1165,6 +1170,11 @@ double RoutePath::trackForIndex(int index) const
 
 double RoutePath::distanceForIndex(int index) const
 {
+    const auto sz = static_cast<int>(d->waypoints.size());
+    if ((index < 0) || (index >= sz)) {
+        return 0.0;
+    }
+
   return d->waypoints[index].pathDistanceM;
 }