class DtStatus => readonly struct DtStatus

src/DotRecast.Detour.Crowd/DtCrowd.cs

@@ -698,7 +698,7 @@ namespace DotRecast.Detour.Crowd
                     // _telemetry.RecordPathWaitTime(ag.targetReplanTime);
                     // Poll path queue.
                     DtStatus status = ag.targetPathQueryResult.status;
-                    if (status != null && status.IsFailed())
+                    if (status.IsFailed())
                     {
                         // Path find failed, retry if the target location is still
                         // valid.
@@ -714,7 +714,7 @@ namespace DotRecast.Detour.Crowd
 
                         ag.targetReplanTime = 0;
                     }
-                    else if (status != null && status.IsSuccess())
+                    else if (status.IsSuccess())
                     {
                         List<long> path = ag.corridor.GetPath();
                         if (0 == path.Count)

src/DotRecast.Detour.Crowd/DtPathQuery.cs

@@ -26,14 +26,12 @@ namespace DotRecast.Detour.Crowd
     {
         /// Path find start and end location.
         public RcVec3f startPos = new RcVec3f();
-
         public RcVec3f endPos = new RcVec3f();
         public long startRef;
         public long endRef;
-        public IDtQueryFilter filter;
         
-        /// < TODO: This is potentially dangerous!
         public readonly DtPathQueryResult result = new DtPathQueryResult();
+        public IDtQueryFilter filter; // < TODO: This is potentially dangerous!
 
         public DtNavMeshQuery navQuery;
     }

src/DotRecast.Detour.Crowd/DtPathQueue.cs

@@ -49,7 +49,7 @@ namespace DotRecast.Detour.Crowd
                 queue.RemoveFirst();
 
                 // Handle query start.
-                if (q.result.status == null)
+                if (q.result.status.IsEmpty())
                 {
                     q.navQuery = new DtNavMeshQuery(navMesh);
                     q.result.status = q.navQuery.InitSlicedFindPath(q.startRef, q.endRef, q.startPos, q.endPos, q.filter, 0);
@@ -89,7 +89,6 @@ namespace DotRecast.Detour.Crowd
             q.startRef = startRef;
             q.endPos = endPos;
             q.endRef = endRef;
-            q.result.status = null;
             q.filter = filter;
             queue.AddLast(q);
             return q.result;

src/DotRecast.Detour/DtStatus.cs

@@ -22,8 +22,10 @@ using System.Runtime.CompilerServices;
 
 namespace DotRecast.Detour
 {
-    public class DtStatus
+    public readonly struct DtStatus
     {
+        public static readonly DtStatus Empty = new DtStatus(0);
+
         // High level status.
         public static readonly DtStatus DT_FAILURE = new DtStatus(1u << 31); // Operation failed. 
         public static readonly DtStatus DT_SUCCSESS = new DtStatus(1u << 30); // Operation succeed. 
@@ -40,7 +42,6 @@ namespace DotRecast.Detour
         public static readonly DtStatus DT_PARTIAL_RESULT = new DtStatus(1 << 6); // Query did not reach the end location, returning best guess. 
         public static readonly DtStatus DT_ALREADY_OCCUPIED = new DtStatus(1 << 7); // A tile has already been assigned to the given x,y coordinate
 
-
         public readonly uint Value;
 
         private DtStatus(uint value)
@@ -48,6 +49,12 @@ namespace DotRecast.Detour
             Value = value;
         }
 
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public bool IsEmpty()
+        {
+            return 0 == Value;
+        }
+
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public bool IsSuccess()
         {
@@ -71,5 +78,17 @@ namespace DotRecast.Detour
         {
             return 0 != (Value & DT_PARTIAL_RESULT.Value);
         }
+
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static DtStatus operator |(DtStatus left, DtStatus right)
+        {
+            return new DtStatus(left.Value | right.Value);
+        }
+        
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static DtStatus operator &(DtStatus left, DtStatus right)
+        {
+            return new DtStatus(left.Value & right.Value);
+        }
     }
 }

src/DotRecast.Detour/QueryResults/Result.cs

@@ -34,7 +34,7 @@ namespace DotRecast.Detour.QueryResults
 
         public static Result<T> InvalidParam<T>()
         {
-            return new Result<T>(default, DtStatus.DT_INVALID_PARAM, null);
+            return new Result<T>(default, DtStatus.DT_FAILURE | DtStatus.DT_INVALID_PARAM, null);
         }
 
         public static Result<T> Failure<T>(string message)
@@ -44,7 +44,7 @@ namespace DotRecast.Detour.QueryResults
 
         public static Result<T> InvalidParam<T>(string message)
         {
-            return new Result<T>(default, DtStatus.DT_INVALID_PARAM, message);
+            return new Result<T>(default, DtStatus.DT_FAILURE | DtStatus.DT_INVALID_PARAM, message);
         }
 
         public static Result<T> Failure<T>(T result)

test/DotRecast.Detour.Test/FindPathTest.cs

@@ -160,7 +160,7 @@ public class FindPathTest : AbstractDetourTest
             var endPos = endPoss[i];
             query.InitSlicedFindPath(startRef, endRef, startPos, endPos, filter, DtNavMeshQuery.DT_FINDPATH_ANY_ANGLE);
             DtStatus status = DtStatus.DT_IN_PROGRESS;
-            while (status == DtStatus.DT_IN_PROGRESS)
+            while (status.IsInProgress())
             {
                 Result<int> res = query.UpdateSlicedFindPath(10);
                 status = res.status;