From 010f05c5659145a9ee377faf609ebfb88813c5de Mon Sep 17 00:00:00 2001
From: Timothy Schenk <admin@rainote.dev>
Date: Mon, 14 Aug 2023 21:07:15 +0200
Subject: [PATCH] feat: init all packetHandler once & reuse

---
 Server/Services/PacketDistributorService.cs | 47 +++++++++++++--------
 1 file changed, 30 insertions(+), 17 deletions(-)

diff --git a/Server/Services/PacketDistributorService.cs b/Server/Services/PacketDistributorService.cs
index 0285469..a1747cc 100644
--- a/Server/Services/PacketDistributorService.cs
+++ b/Server/Services/PacketDistributorService.cs
@@ -1,13 +1,14 @@
 namespace Server.Services;
 
 using System.Collections.Concurrent;
+using System.Collections.Immutable;
 using System.Reflection;
+using DotNext.Collections.Generic;
 using MassTransit.Internals;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Hosting;
 using Microsoft.Extensions.Logging;
 using Microsoft.VisualBasic.CompilerServices;
-using Newtonsoft.Json;
 using PacketHandlers;
 using Packets;
 using static DotNext.Metaprogramming.CodeGenerator;
@@ -17,8 +18,12 @@ public class PacketDistributorService : IHostedService
 {
     private readonly ConcurrentQueue<RawPacket> concurrentQueue;
     private readonly ILogger<PacketDistributorService> logger;
-    private readonly Dictionary<OperationCode, Type> packetHandlers;
-    private readonly Dictionary<OperationCode, Func<byte[], IPacket>> deserializationMap;
+    private readonly ConcurrentDictionary<OperationCode, object> packetHandlersInstantiation;
+
+    private readonly
+        ImmutableDictionary<OperationCode,
+            Func<byte[], IPacket>> deserializationMap;
+
     private readonly IServiceProvider serviceProvider;
 
     public PacketDistributorService(ILogger<PacketDistributorService> logger, IServiceProvider serviceProvider)
@@ -26,29 +31,38 @@ public class PacketDistributorService : IHostedService
         this.concurrentQueue = new ConcurrentQueue<RawPacket>();
         this.logger = logger;
         this.serviceProvider = serviceProvider;
-        this.packetHandlers = new Dictionary<OperationCode, Type>();
-        this.deserializationMap = new Dictionary<OperationCode, Func<byte[], IPacket>>();
+        var tempDeserializationMap =
+            new Dictionary<OperationCode, Func<byte[], IPacket>>();
 
         var executingAssembly = Assembly.GetExecutingAssembly();
         var packetsTypes = this.GetPacketsWithId(executingAssembly);
-        this.packetHandlers = this.GetAllPacketHandlersWithId(executingAssembly);
-
+        var packetHandlers = this.GetAllPacketHandlersWithId(executingAssembly);
+        this.packetHandlersInstantiation = new ConcurrentDictionary<OperationCode, object>();
+        packetHandlers.ForEach(x =>
+        {
+            var packetHandler =
+                ActivatorUtilities.GetServiceOrCreateInstance(this.serviceProvider,
+                    x.Value);
+            this.packetHandlersInstantiation.TryAdd(x.Key, packetHandler);
+        });
         foreach (var packetsType in packetsTypes)
         {
             var lambda = Lambda<Func<byte[], IPacket>>(fun =>
             {
-                var arg = fun[0];
+                var argPacketData = fun[0];
                 var newPacket = packetsType.Value.New();
 
                 var packetVariable = DeclareVariable(packetsType.Value, "packet");
                 Assign(packetVariable, newPacket);
-                Call(packetVariable, nameof(IPacket.Deserialize), arg);
+                Call(packetVariable, nameof(IPacket.Deserialize), argPacketData);
 
                 Return(packetVariable);
             }).Compile();
             logger.LogInformation("Packet creation function created for {Opcode}", packetsType.Key);
-            this.deserializationMap.Add(packetsType.Key, lambda);
+            tempDeserializationMap.Add(packetsType.Key, lambda);
         }
+
+        this.deserializationMap = tempDeserializationMap.ToImmutableDictionary();
     }
 
     public Task StartAsync(CancellationToken cancellationToken) => Task.CompletedTask;
@@ -81,7 +95,8 @@ public class PacketDistributorService : IHostedService
             t is { IsClass: true, IsAbstract: false } && t
                 .GetInterfaces().Any(i =>
                     i.IsGenericType && i.GetGenericTypeDefinition() == typeof(IPacketHandler<>))).ToDictionary(type =>
-            type.GetInterfaces().First(t =>t is { IsGenericType: true} && t.GetGenericTypeDefinition() == typeof(IPacketHandler<>))
+            type.GetInterfaces().First(t =>
+                    t is { IsGenericType: true } && t.GetGenericTypeDefinition() == typeof(IPacketHandler<>))
                 .GetGenericArguments().First().GetCustomAttribute<PacketIdAttribute>()!.Code);
 
         if (packetHandlersWithId is not { Count: 0 })
@@ -126,12 +141,10 @@ public class PacketDistributorService : IHostedService
         }
 
         var packet = this.deserializationMap[item.OperationCode](item.MessageBody);
-        var packetHandler =
-            ActivatorUtilities.GetServiceOrCreateInstance(this.serviceProvider,
-                this.packetHandlers[item.OperationCode]);
-        packetHandler.GetType().GetMethod("HandleAsync")
-            ?.Invoke(packetHandler, new object[] { packet, item.Session });
-        this.logger.LogDebug("Packet data {PacketData}", JsonConvert.SerializeObject(packet));
+        this.packetHandlersInstantiation[item.OperationCode].GetType().GetMethod("HandleAsync")
+            ?.Invoke(this.packetHandlersInstantiation[item.OperationCode], new object[] { packet, item.Session });
+
+        //this.logger.LogDebug("Packet data {PacketData}", JsonConvert.SerializeObject(packet));
         this.logger.LogTrace("[{TempId}] Packet with ID: {MessageOperationCode} has finished",
             item.Session.Id,
             item.OperationCode);