From edb41ad67be7bc95ec7d822763b2372af875795a Mon Sep 17 00:00:00 2001
From: Andras Schaffer <eosbandi@gmail.com>
Date: Wed, 1 Nov 2023 00:52:27 +0100
Subject: [PATCH] Fix Proximity UI concurrencty issue

---
 Controls/ProximityControl.cs   | 12 ++++++++++--
 ExtLibs/ArduPilot/Proximity.cs | 33 +++++++++++++++++++--------------
 2 files changed, 29 insertions(+), 16 deletions(-)

diff --git a/Controls/ProximityControl.cs b/Controls/ProximityControl.cs
index 43cd008733..513ece5c84 100644
--- a/Controls/ProximityControl.cs
+++ b/Controls/ProximityControl.cs
@@ -18,6 +18,7 @@ public class ProximityControl : Form
 
         MAVState _parent;
         private Proximity.directionState _dS => _parent?.Proximity?.DirectionState;
+        private bool _drawingInProgress => _parent?.Proximity?.DrawingInProgress ?? false;
 
         private Timer timer1;
         private IContainer components;
@@ -90,6 +91,8 @@ private void Temp_KeyPress(object sender, KeyPressEventArgs e)
 
         private void Temp_Paint(object sender, PaintEventArgs e)
         {
+            if (_parent.Proximity != null)
+                _parent.Proximity.DrawingInProgress = true;
             e.Graphics.Clear(BackColor);
 
             var midx = e.ClipRectangle.Width / 2.0f;
@@ -111,14 +114,18 @@ private void Temp_Paint(object sender, PaintEventArgs e)
                     e.Graphics.DrawImage(Resources.quadicon, midx - imw, midy - imw, size, size);
                     break;
             }
-            
+
             if (_dS == null)
+            {
+                if (_parent.Proximity != null)
+                    _parent.Proximity.DrawingInProgress = false;
                 return;
+            }
 
             Pen redpen = new Pen(Color.Red, 3);
             Pen yellowpen = new Pen(Color.Yellow, 3);
             var font = new Font(SystemFonts.DefaultFont.FontFamily, SystemFonts.DefaultFont.Size + 2, FontStyle.Bold);
-                 
+
             float move = 5;
 
             for (float x = 50f; x <= screenradius; x+=50f)
@@ -205,6 +212,7 @@ private void Temp_Paint(object sender, PaintEventArgs e)
                         break;
                 }
             }
+            _parent.Proximity.DrawingInProgress = false;
         }
 
         public new void Show()
diff --git a/ExtLibs/ArduPilot/Proximity.cs b/ExtLibs/ArduPilot/Proximity.cs
index c9eeab63ad..81e2bc8f9d 100644
--- a/ExtLibs/ArduPilot/Proximity.cs
+++ b/ExtLibs/ArduPilot/Proximity.cs
@@ -24,8 +24,9 @@ public class Proximity : IDisposable
         private byte compid;
 
         public bool DataAvailable { get; set; } = false;
+        public bool DrawingInProgress { get; set; } = false;
 
-        public Proximity(MAVState mavInt, byte sysid, byte compid) 
+        public Proximity(MAVState mavInt, byte sysid, byte compid)
         {
             this.sysid = sysid;
             this.compid = compid;
@@ -47,6 +48,7 @@ public Proximity(MAVState mavInt, byte sysid, byte compid)
 
         private bool messageReceived(MAVLinkMessage arg)
         {
+            if (DrawingInProgress) return true;
             //accept any compid, but filter sysid
             if (arg.sysid != _parent.sysid)
                 return true;
@@ -64,7 +66,7 @@ private bool messageReceived(MAVLinkMessage arg)
                 _dS.Add(dist.id, (MAV_SENSOR_ORIENTATION)dist.orientation, dist.current_distance, DateTime.Now, 3);
 
                 DataAvailable = true;
-            } 
+            }
             else if (arg.msgid == (uint) MAVLINK_MSG_ID.OBSTACLE_DISTANCE)
             {
                 var dists = arg.ToStructure<mavlink_obstacle_distance_t>();
@@ -89,7 +91,7 @@ private bool messageReceived(MAVLinkMessage arg)
                     if(dists.distances[a] == ushort.MaxValue)
                         continue;
                     if(dists.distances[a] > dists.max_distance)
-                        continue;    
+                        continue;
                     if(dists.distances[a] < dists.min_distance)
                         continue;
 
@@ -135,7 +137,7 @@ public data(uint id, MAV_SENSOR_ORIENTATION orientation, double distance, DateTi
                     Distance = distance;
                     Received = received;
                     Age = age;
-                }       
+                }
 
                 public data(uint id, double angle, double size, double distance, DateTime received, double age = 1)
                 {
@@ -161,20 +163,23 @@ public void Add(uint id, MAV_SENSOR_ORIENTATION orientation, double distance, Da
                 _dists.Add(new data(id, orientation, distance, received, age));
 
                 expire();
-            }      
-            
+            }
+
             public void Add(uint id, double angle, double size, double distance, DateTime received, double age = 1)
             {
-                var existing = _dists.Where((a) => { return a.SensorId == id && a.Angle == angle; });
-
-                foreach (var item in existing.ToList())
+                lock (this)
                 {
-                    _dists.Remove(item);
-                }
+                    var existing = _dists.Where((a) => { return a.SensorId == id && a.Angle == angle; });
 
-                _dists.Add(new data(id, angle, size, distance, received, age));
+                    foreach (var item in existing.ToList())
+                    {
+                        _dists.Remove(item);
+                    }
 
-                expire();
+                    _dists.Add(new data(id, angle, size, distance, received, age));
+
+                    expire();
+                }
             }
 
             /// <summary>
@@ -230,7 +235,7 @@ void expire()
                 {
                     for (int a = 0; a < _dists.Count; a++)
                     {
-                        var expireat = _dists[a].ExpireTime;
+                        var expireat = _dists[a]?.ExpireTime;
 
                         if (expireat < DateTime.Now)
                         {