Handling for caching pointers to userdata objects

PorygonSharp/EvalValues/EvalValueCreator.cs

@@ -16,8 +16,8 @@ namespace PorygonSharp.EvalValues
             if (type.IsEnum && !type.IsGenericParameter)
             {
                 var typeHash = UserDataHandler.GetTypeId(type);
-                var handle   = GCHandle.Alloc(o, GCHandleType.WeakTrackResurrection);
+                var ptr = ObjectEvalValueHandler.GetObjectPtr(o);
-                return new EvalValue(CreateUserDataEvalValue(typeHash, GCHandle.ToIntPtr(handle)));
+                return new EvalValue(CreateUserDataEvalValue(typeHash, ptr));
             }
             var typeCode = Type.GetTypeCode(type);
             switch (typeCode)
@@ -48,8 +48,8 @@ namespace PorygonSharp.EvalValues
                         throw new Exception($"Type is not registered for use: {type.FullName}");
                     }
                     var typeHash = UserDataHandler.GetTypeId(type);
-                    var handle   = GCHandle.Alloc(o, GCHandleType.WeakTrackResurrection);
+                    var ptr = ObjectEvalValueHandler.GetObjectPtr(o);
-                    return new EvalValue(CreateUserDataEvalValue(typeHash, GCHandle.ToIntPtr(handle)));
+                    return new EvalValue(CreateUserDataEvalValue(typeHash, ptr));
                 default:
                     throw new Exception($"Type {type} is not currently available as EvalValue");
             }

PorygonSharp/EvalValues/ListEvalValue.cs

@@ -1,6 +1,5 @@
 using System;
 using System.Collections;
-using System.Diagnostics;
 using System.Runtime.InteropServices;
 
 namespace PorygonSharp.EvalValues
@@ -22,8 +21,7 @@ namespace PorygonSharp.EvalValues
             if (valueType == null)
                 throw new ArgumentNullException();
 
-            var parentHandle = GCHandle.Alloc(list, GCHandleType.WeakTrackResurrection);
+            ParentCollection = ObjectEvalValueHandler.GetObjectPtr(list);
-            ParentCollection = GCHandle.ToIntPtr(parentHandle);
             Getter = Marshal.GetFunctionPointerForDelegate(new GetterDelegate((parent, index) =>
             {
                 var val = new EvalValue(index).EvaluateInteger();

PorygonSharp/EvalValues/ObjectEvalValueHandler.cs

@@ -0,0 +1,44 @@
+using System;
+using System.Collections.Generic;
+using System.Runtime.InteropServices;
+
+namespace PorygonSharp.EvalValues
+{
+    internal static class ObjectEvalValueHandler
+    {
+        private struct PtrObject
+        {
+            public readonly IntPtr Pointer;
+            public readonly WeakReference<object> WeakReference;
+
+            public PtrObject(IntPtr pointer, WeakReference<object> weakReference)
+            {
+                Pointer = pointer;
+                WeakReference = weakReference;
+            }
+        }
+        
+        private static readonly Dictionary<int, PtrObject> CreatedPointers = new Dictionary<int, PtrObject>();
+
+        public static IntPtr GetObjectPtr(object o)
+        {
+            var hash = o.GetHashCode();
+            if (CreatedPointers.TryGetValue(hash, out var ptrObject))
+            {
+                if (ptrObject.WeakReference.TryGetTarget(out _))
+                {
+                    return ptrObject.Pointer;
+                }
+                else
+                {
+                    CreatedPointers.Remove(hash);
+                }
+            }
+            var handle   = GCHandle.Alloc(o, GCHandleType.WeakTrackResurrection);
+            var ptr = GCHandle.ToIntPtr(handle);
+            ptrObject = new PtrObject(ptr, new WeakReference<object>(o));
+            CreatedPointers.Add(o.GetHashCode(), ptrObject);
+            return ptrObject.Pointer;
+        }
+    }
+}

PorygonSharp/UserData/UserData.cs

@@ -160,14 +160,12 @@ namespace PorygonSharp.UserData
             if (_implicitCasts.TryGetValue(expectedType, out var func))
             {
                 var castVal = func.Invoke(null, new[] {obj});
-                var handle = GCHandle.Alloc(castVal, GCHandleType.WeakTrackResurrection);
+                return EvalValueCreator.CreateValue(castVal).GetPointer();
-                return GCHandle.ToIntPtr(handle);
             }
             if (_explicitCasts.TryGetValue(expectedType, out func))
             {
                 var castVal = func.Invoke(null, new[] {obj});
-                var handle = GCHandle.Alloc(castVal, GCHandleType.WeakTrackResurrection);
+                return EvalValueCreator.CreateValue(castVal).GetPointer();
-                return GCHandle.ToIntPtr(handle);
             }
             throw new Exception("Invalid cast kind");
         }