From 2afec07cab439479d3e652b533db5de9a4b4867b Mon Sep 17 00:00:00 2001
From: ManuG85 <manuelgeesen@web.de>
Date: Thu, 27 Apr 2017 22:30:26 +0200
Subject: [PATCH 1/4] Before (de)serialization callbacks

Introduced a callback to get informed about a type before an instance of it gets serialized and another one to get informed about an type id before it gets used to deserialize an object.
---
 NetSerializer/Settings.cs | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/NetSerializer/Settings.cs b/NetSerializer/Settings.cs
index 94880da..54b5471 100644
--- a/NetSerializer/Settings.cs
+++ b/NetSerializer/Settings.cs
@@ -13,6 +13,16 @@ namespace NetSerializer
 {
 	public class Settings
 	{
+		/// <summary>
+		/// Gets called when an object is going to be deserialized.
+		/// </summary>
+		public Action<uint> BeforeDeserializingObjectWithTypeId;
+        
+		/// <summary>
+		/// Gets called when an object is going to be serialized.
+		/// </summary>
+		public Action<Type> BeforeSerializingObjectOfType;
+		
 		/// <summary>
 		/// Array of custom TypeSerializers
 		/// </summary>

From e80b415efd164ad82044018c858fefb8f516bc03 Mon Sep 17 00:00:00 2001
From: ManuG85 <manuelgeesen@web.de>
Date: Thu, 27 Apr 2017 22:32:27 +0200
Subject: [PATCH 2/4] Invoke before (de)serialization callbacks

---
 NetSerializer/TypeSerializers/ObjectSerializer.cs | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/NetSerializer/TypeSerializers/ObjectSerializer.cs b/NetSerializer/TypeSerializers/ObjectSerializer.cs
index 9b8bbd9..0cab29b 100644
--- a/NetSerializer/TypeSerializers/ObjectSerializer.cs
+++ b/NetSerializer/TypeSerializers/ObjectSerializer.cs
@@ -46,6 +46,8 @@ public static void Serialize(Serializer serializer, Stream stream, object ob)
 
 			var type = ob.GetType();
 
+			serializer.Settings.BeforeSerializingObjectOfType?.Invoke(type);
+
 			SerializeDelegate<object> del;
 
 			uint id = serializer.GetTypeIdAndSerializer(type, out del);
@@ -75,6 +77,8 @@ public static void Deserialize(Serializer serializer, Stream stream, out object
 				ob = new object();
 				return;
 			}
+			
+			serializer.Settings.BeforeDeserializingObjectWithTypeId?.Invoke(id);
 
 			var del = serializer.GetDeserializeTrampolineFromId(id);
 			del(serializer, stream, out ob);

From 1253c752301f171f8464eff526fb534ae0ad0c03 Mon Sep 17 00:00:00 2001
From: ManuG85 <manuelgeesen@web.de>
Date: Thu, 27 Apr 2017 22:35:42 +0200
Subject: [PATCH 3/4] Collect used types

Set before (de)serialization callbacks to collect used types.
---
 Test/Tester.cs | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/Test/Tester.cs b/Test/Tester.cs
index 3775121..557b73c 100644
--- a/Test/Tester.cs
+++ b/Test/Tester.cs
@@ -9,6 +9,14 @@ namespace Test
 {
 	class Tester
 	{
+		private static HashSet<Type> m_serializedTypes = new HashSet<Type>();
+		
+		private static HashSet<uint> m_deserializedTypeIds = new HashSet<uint>();
+		
+		public static IEnumerable<Type> SerializedTypes => m_serializedTypes;
+		
+		public static IEnumerable<uint> DeserializedTypeIds => m_deserializedTypeIds;
+		
 		public static NS.Serializer CreateSerializer()
 		{
 			var types = GetKnownTypes().ToArray();
@@ -18,6 +26,8 @@ public static NS.Serializer CreateSerializer()
 			var settings = new NS.Settings()
 			{
 				CustomTypeSerializers = new NS.ITypeSerializer[] { new TriDimArrayCustomSerializer() },
+				BeforeSerializingObjectOfType = type => m_serializedTypes.Add(type),
+				BeforeDeserializingObjectWithTypeId = id => m_deserializedTypeIds.Add(id)
 			};
 
 			var serializer = new NS.Serializer(types, settings);

From 9d26a4a8ef520b70f384d4ced52d9bf5e1701faf Mon Sep 17 00:00:00 2001
From: ManuG85 <manuelgeesen@web.de>
Date: Thu, 27 Apr 2017 22:41:56 +0200
Subject: [PATCH 4/4] Print types to check (de)serialization callbacks

Print the types used for serialization and the type ids used while deserializing objects.
---
 Test/Program.cs | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/Test/Program.cs b/Test/Program.cs
index 0b5b0e7..87107e3 100644
--- a/Test/Program.cs
+++ b/Test/Program.cs
@@ -41,6 +41,22 @@ static void Main(string[] args)
 
 			foreach (var thread in threads)
 				thread.Join();
+			
+			Console.WriteLine();
+			Console.WriteLine("Serialized objects of types:");
+			foreach (var type in Tester.SerializedTypes.OrderBy(x => x.FullName))
+			{
+				Console.WriteLine(type.FullName);
+			}
+
+			Console.WriteLine();
+			Console.WriteLine("Deserialized objects with type ids:");
+			foreach (var id in Tester.DeserializedTypeIds.OrderBy(x => x))
+			{
+				Console.WriteLine(id);
+			}
+
+			Console.ReadKey();
 		}
 
 		static bool ParseArgs(string[] args)