1 files changed, 45 insertions, 0 deletions
diff --git a/src/MessagePack.UnityClient/Assets/Scripts/MessagePack/Resolvers/ResolverUtilities.cs b/src/MessagePack.UnityClient/Assets/Scripts/MessagePack/Resolvers/ResolverUtilities.cs
new file mode 100644
index 00000000..a6622181
--- /dev/null
+++ b/src/MessagePack.UnityClient/Assets/Scripts/MessagePack/Resolvers/ResolverUtilities.cs
@@ -0,0 +1,45 @@
+// Copyright (c) All contributors. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+using System;
+using System.Reflection;
+using MessagePack.Formatters;
+
+namespace MessagePack.Internal
+{
+    internal static class ResolverUtilities
+    {
+        internal static IMessagePackFormatter ActivateFormatter(Type formatterType, object[] args = null)
+        {
+            if (args == null || args.Length == 0)
+            {
+                if (formatterType.GetConstructor(Type.EmptyTypes) is ConstructorInfo ctor)
+                {
+                    return (IMessagePackFormatter)ctor.Invoke(Array.Empty<object>());
+                }
+                else if (FetchSingletonField(formatterType) is FieldInfo instance)
+                {
+                    return (IMessagePackFormatter)instance.GetValue(null);
+                }
+                else
+                {
+                    throw new MessagePackSerializationException($"The {formatterType.FullName} formatter has no default constructor nor implements the singleton pattern.");
+                }
+            }
+            else
+            {
+                return (IMessagePackFormatter)Activator.CreateInstance(formatterType, args);
+            }
+        }
+
+        internal static FieldInfo FetchSingletonField(Type formatterType)
+        {
+            if (formatterType.GetField("Instance", BindingFlags.Static | BindingFlags.Public) is FieldInfo fieldInfo && fieldInfo.IsInitOnly)
+            {
+                return fieldInfo;
+            }
+
+            return null;
+        }
+    }
+}