fix: Fixes serializing strings and uses memory mapped files for loading (#1133)

Projects/Server/Serialization/AdhocPersistence.cs

@@ -15,44 +15,91 @@
 
 using System;
 using System.IO;
+using System.IO.MemoryMappedFiles;
+using System.Runtime.CompilerServices;
+using System.Threading.Tasks;
 
-namespace Server
+namespace Server;
+
+public static class AdhocPersistence
 {
-    public static class AdhocPersistence
+    /**
+     * Serializes to memory synchronously. Optional buffer can be provided.
+     * Note: The buffer may not be the same after returning from the function if more data is written
+     * than the initial buffer can handle.
+     */
+    public static BufferWriter Serialize(Action<IGenericWriter> serializer)
     {
-        public static void Serialize(string filePath, Action<IGenericWriter> serializer)
-        {
-            var fullPath = Path.Combine(Core.BaseDirectory, filePath);
-            var file = new FileInfo(fullPath);
-            file.Directory?.Create();
+        var saveBuffer = new BufferWriter(true);
+        serializer(saveBuffer);
+        return saveBuffer;
+    }
 
-            using var bin = new BinaryFileWriter(fullPath, true);
-            serializer(bin);
+    /**
+     * Writes a buffer to disk. This function should be called asynchronously.
+     */
+    public static void WriteSnapshot(string filePath, Span<byte> buffer)
+    {
+        var fullPath = PathUtility.GetFullPath(filePath, Core.BaseDirectory);
+        var file = new FileInfo(fullPath);
+        PathUtility.EnsureDirectory(file.DirectoryName);
+
+        using var fs = new FileStream(fullPath, FileMode.Create, FileAccess.Write);
+        fs.Write(buffer);
+    }
+
+    public static void SerializeAndSnapshot(string filePath, Action<IGenericWriter> serializer)
+    {
+        var saveBuffer = Serialize(serializer);
+        Task.Run(() => { WriteSnapshot(filePath, saveBuffer.Buffer.AsSpan(0, (int)saveBuffer.Position)); });
+    }
+
+    public static void Deserialize(string filePath, Action<IGenericReader> deserializer)
+    {
+        var fullPath = PathUtility.GetFullPath(filePath, Core.BaseDirectory);
+        var file = new FileInfo(fullPath);
+
+        if (!file.Exists)
+        {
+            return;
         }
 
-        public static void Deserialize(string filePath, Action<IGenericReader> deserializer)
+        var fileLength = file.Length;
+        if (fileLength == 0)
         {
-            var fullPath = Path.Combine(Core.BaseDirectory, filePath);
-            var file = new FileInfo(fullPath);
-            file.Directory?.Create();
+            return;
+        }
 
-            if (!file.Exists)
-            {
-                return;
-            }
+        string error;
 
-            try
+        try
+        {
+            using var mmf = MemoryMappedFile.CreateFromFile(fullPath, FileMode.Open);
+            using var stream = mmf.CreateViewStream();
+            using var br = new BinaryFileReader(stream);
+            deserializer(br);
+
+            error = br.Position != fileLength
+                ? $"Serialized {fileLength} bytes, but {br.Position} bytes deserialized"
+                : null;
+        }
+        catch (Exception e)
+        {
+            error = e.ToString();
+        }
+
+        if (error != null)
+        {
+            Console.WriteLine($"***** Bad deserialize of {file.FullName} *****");
+            Console.WriteLine(error);
+
+            Console.WriteLine("Skip this file and continue? (y/n)");
+
+            var pressedKey = Console.ReadKey(true).Key;
+
+            if (pressedKey != ConsoleKey.Y)
             {
-                using FileStream fs = new FileStream(fullPath, FileMode.Open, FileAccess.Read, FileShare.Read);
-                using var br = new BinaryFileReader(fs);
-                deserializer(br);
-            }
-            catch (Exception e)
-            {
-                Utility.PushColor(ConsoleColor.Red);
-                Console.WriteLine($"***** Bad deserialize of {file.FullName} *****");
-                Console.WriteLine(e.ToString());
-                Utility.PopColor();
+                throw new Exception("Deserialization failed.");
             }
         }
     }