Separate MHServerEmu.Core into a library

MHServerEmu.sln

@@ -7,6 +7,8 @@ Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "MHServerEmu", "src\MHServer
 EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Gazillion", "src\Gazillion\Gazillion.csproj", "{7D085437-F307-49D6-AF7A-C3B3DF4E4189}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "MHServerEmu.Core", "src\MHServerEmu.Core\MHServerEmu.Core.csproj", "{667BA21C-0E76-450A-9854-93D0C4C3D79E}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|x64 = Debug|x64
@@ -21,6 +23,10 @@ Global
 		{7D085437-F307-49D6-AF7A-C3B3DF4E4189}.Debug|x64.Build.0 = Debug|x64
 		{7D085437-F307-49D6-AF7A-C3B3DF4E4189}.Release|x64.ActiveCfg = Release|x64
 		{7D085437-F307-49D6-AF7A-C3B3DF4E4189}.Release|x64.Build.0 = Release|x64
+		{667BA21C-0E76-450A-9854-93D0C4C3D79E}.Debug|x64.ActiveCfg = Debug|x64
+		{667BA21C-0E76-450A-9854-93D0C4C3D79E}.Debug|x64.Build.0 = Debug|x64
+		{667BA21C-0E76-450A-9854-93D0C4C3D79E}.Release|x64.ActiveCfg = Release|x64
+		{667BA21C-0E76-450A-9854-93D0C4C3D79E}.Release|x64.Build.0 = Release|x64
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE

src/MHServerEmu.Core/Helpers/CompressionHelper.cs

@@ -0,0 +1,34 @@
+using Free.Ports.zLib;
+using K4os.Compression.LZ4;
+
+namespace MHServerEmu.Core.Helpers
+{
+    public static class CompressionHelper
+    {
+        /// <summary>
+        /// Decompresses the provided LZ4 buffer.
+        /// </summary>
+        public static void LZ4Decode(byte[] source, byte[] target)
+        {
+            LZ4Codec.Decode(source, target);
+        }
+
+        /// <summary>
+        /// Compresses the provided buffer using zlib.
+        /// </summary>
+        public static byte[] ZLibDeflate(byte[] buffer)
+        {
+            // This is used for compressing the achievement database dump before sending it to clients.
+            // We need to compress specifically with a port of zlib rather than various alternatives like SharpZipLib
+            // to produce the same result as the original. zlib.compress() in Python also produces the result we need.
+
+            using (MemoryStream ms = new())
+            using (ZStreamWriter writer = new(ms))
+            {
+                writer.Write(buffer);
+                writer.Close();
+                return ms.ToArray();
+            }
+        }
+    }
+}

src/MHServerEmu.Core/MHServerEmu.Core.csproj

@@ -0,0 +1,29 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net6.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>disable</Nullable>
+    <Platforms>x64</Platforms>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\Gazillion\Gazillion.csproj" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <Reference Include="Free.Ports.zLib">
+      <HintPath>..\..\dep\Free.Ports.zLib\Free.Ports.zLib.dll</HintPath>
+    </Reference>
+    <Reference Include="Google.ProtocolBuffers">
+      <HintPath>..\..\dep\protobuf-csharp\Google.ProtocolBuffers.dll</HintPath>
+    </Reference>
+    <Reference Include="INIFileParser">
+      <HintPath>..\..\dep\ini-parser\INIFileParser.dll</HintPath>
+    </Reference>
+    <Reference Include="K4os.Compression.LZ4">
+      <HintPath>..\..\dep\K4os.Compression.LZ4\K4os.Compression.LZ4.dll</HintPath>
+    </Reference>
+  </ItemGroup>
+
+</Project>

src/MHServerEmu/Games/Achievements/AchievementDatabase.cs

@@ -1,6 +1,5 @@
 using System.Diagnostics;
 using System.Text.Json;
-using Free.Ports.zLib;
 using Google.ProtocolBuffers;
 using Gazillion;
 using MHServerEmu.Core.Helpers;
@@ -186,19 +185,13 @@ namespace MHServerEmu.Games.Achievements
                 .SetAchievementNewThresholdUS((ulong)AchievementNewThresholdUS.TotalSeconds)
                 .Build().ToByteArray();
 
-            // We need to compress specifically with a port of zlib rather than various alternatives like SharpZipLib
-            // to produce the same result. zlib.compress() in Python also produces the result we need.
+            // NOTE: If you don't use the right library to compress this it's going to cause client-side errors.
+            // See CompressionHelper.ZLibDeflate() for more details.
+            byte[] compressedBuffer = CompressionHelper.ZLibDeflate(dumpBuffer);
 
-            using (MemoryStream ms = new())
-            using (ZStreamWriter writer = new(ms))
-            {
-                writer.Write(dumpBuffer);
-                writer.Close();
-
-               _cachedDump = NetMessageAchievementDatabaseDump.CreateBuilder()
-                    .SetCompressedAchievementDatabaseDump(ByteString.CopyFrom(ms.ToArray()))
-                    .Build();
-            }
+            _cachedDump = NetMessageAchievementDatabaseDump.CreateBuilder()
+                 .SetCompressedAchievementDatabaseDump(ByteString.CopyFrom(compressedBuffer))
+                 .Build();
         }
     }
 }

src/MHServerEmu/Games/GameData/PakFile.cs

@@ -1,5 +1,5 @@
-using K4os.Compression.LZ4;
-using MHServerEmu.Core.Extensions;
+using MHServerEmu.Core.Extensions;
+using MHServerEmu.Core.Helpers;
 using MHServerEmu.Core.Logging;
 
 namespace MHServerEmu.Games.GameData
@@ -76,7 +76,7 @@ namespace MHServerEmu.Games.GameData
             }
 
             byte[] uncompressedData = new byte[entry.UncompressedSize];
-            LZ4Codec.Decode(entry.CompressedData, uncompressedData);
+            CompressionHelper.LZ4Decode(entry.CompressedData, uncompressedData);
             return new(uncompressedData);
         }
 

src/MHServerEmu/MHServerEmu.csproj

@@ -22,24 +22,16 @@
 
   <ItemGroup>
     <ProjectReference Include="..\Gazillion\Gazillion.csproj" />
+    <ProjectReference Include="..\MHServerEmu.Core\MHServerEmu.Core.csproj" />
   </ItemGroup>
 
   <ItemGroup>
     <Reference Include="Dapper">
       <HintPath>..\..\dep\Dapper\Dapper.dll</HintPath>
     </Reference>
-    <Reference Include="Free.Ports.zLib">
-      <HintPath>..\..\dep\Free.Ports.zLib\Free.Ports.zLib.dll</HintPath>
-    </Reference>
     <Reference Include="Google.ProtocolBuffers">
       <HintPath>..\..\dep\protobuf-csharp\Google.ProtocolBuffers.dll</HintPath>
     </Reference>
-    <Reference Include="INIFileParser">
-      <HintPath>..\..\dep\ini-parser\INIFileParser.dll</HintPath>
-    </Reference>
-    <Reference Include="K4os.Compression.LZ4">
-      <HintPath>..\..\dep\K4os.Compression.LZ4\K4os.Compression.LZ4.dll</HintPath>
-    </Reference>
     <Reference Include="System.Data.SQLite">
       <HintPath>..\..\dep\System.Data.SQLite\System.Data.SQLite.dll</HintPath>
     </Reference>