Refactor struct serializer generator with explicit opt-in

Changes struct serializer generator to require explicit [GenerateStructSerializer] attribute instead of auto-detecting fields with [EmulatedInline]/[EmulatedPointer]. Major internal refactoring includes:

- Replace implicit detection with explicit opt-in via marker attribute
- Refactor field processing into FieldSlot-based recursive walking for better nested struct/array support
- Add diagnostic reporting for unsupported field types and nesting depth limits

Brovan/Core/Emulation/OS/Linux/LinuxStructs.cs

@@ -4,6 +4,7 @@ using Brovan.Core.Emulation.OS.Linux.Files;
 
 namespace Brovan.Core.Emulation.OS.Linux
 {
+    [GenerateStructSerializer]
     public struct Utsname
     {
         [EmulatedInline(65, Ascii = true)]
@@ -26,6 +27,7 @@ namespace Brovan.Core.Emulation.OS.Linux
     }
 
 
+    [GenerateStructSerializer]
     [StructLayout(LayoutKind.Explicit)]
     public struct LinuxStat32
     {
@@ -90,6 +92,7 @@ namespace Brovan.Core.Emulation.OS.Linux
         public uint __unused5;
     }
 
+    [GenerateStructSerializer]
     [StructLayout(LayoutKind.Explicit)]
     public struct LinuxStatCompat64
     {
@@ -162,6 +165,7 @@ namespace Brovan.Core.Emulation.OS.Linux
         public long tv_nsec;
     }
 
+    [GenerateStructSerializer]
     [StructLayout(LayoutKind.Explicit)]
     public struct LinuxStat64
     {

Brovan/Core/Emulation/OS/SharedHelpers/StructSerializer.cs

@@ -25,6 +25,16 @@ namespace Brovan.Core.Emulation.OS
         public EmulatedInlineAttribute(int Size) => this.Size = Size;
     }
 
+    /// <summary>
+    /// Opts a struct into <see cref="Brovan.Generators.StructSerializerGenerator"/>, which emits
+    /// reflection-free WriteStructDirect_/ParseStructDirect_/GetStructSizeDirect_ methods on
+    /// <see cref="StructSerializer"/> for it.
+    /// </summary>
+    [AttributeUsage(AttributeTargets.Struct)]
+    public sealed class GenerateStructSerializerAttribute : Attribute
+    {
+    }
+
     public enum WriteStructError
     {
         None, NullDestination, DestinationNotMapped, PointerAllocationFailed,
@@ -186,6 +196,31 @@ namespace Brovan.Core.Emulation.OS
             return Cache[T] = new TypeDesc(T);
         }
 
+        // --- Generated-serializer dispatch ---
+
+        internal delegate bool ParseStructAddrDelegate<T>(BinaryEmulator Emulator, ulong Address, out T Value);
+        internal delegate bool ParseStructBytesDelegate<T>(BinaryEmulator Emulator, byte[] Raw, out T Value);
+
+        private static readonly Dictionary<Type, Delegate> DirectWrite = new();
+        private static readonly Dictionary<Type, Delegate> DirectParseAddr = new();
+        private static readonly Dictionary<Type, Delegate> DirectParseBytes = new();
+        private static readonly Dictionary<Type, Delegate> DirectSizeBool = new();
+        private static readonly Dictionary<Type, Delegate> DirectSizeEmulator = new();
+
+        internal static void RegisterDirect<T>(
+            Func<BinaryEmulator, ulong, T, WriteStructResult> Write,
+            ParseStructAddrDelegate<T> ParseAddr,
+            ParseStructBytesDelegate<T> ParseBytes,
+            Func<bool, int> SizeBool,
+            Func<BinaryEmulator, int> SizeEmulator) where T : struct
+        {
+            DirectWrite[typeof(T)] = Write;
+            DirectParseAddr[typeof(T)] = ParseAddr;
+            DirectParseBytes[typeof(T)] = ParseBytes;
+            DirectSizeBool[typeof(T)] = SizeBool;
+            DirectSizeEmulator[typeof(T)] = SizeEmulator;
+        }
+
         // --- Public API ---
 
         /// <summary>
@@ -196,6 +231,9 @@ namespace Brovan.Core.Emulation.OS
         /// <returns>return the size.</returns>
         public static uint GetStructSize<[DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicFields | DynamicallyAccessedMemberTypes.NonPublicFields)] T>(BinaryEmulator Emulator) where T : struct
         {
+            if (DirectSizeEmulator.TryGetValue(typeof(T), out Delegate Fast))
+                return (uint)((Func<BinaryEmulator, int>)Fast)(Emulator);
+
             bool Is64 = Emulator._binary.Architecture == BinaryArchitecture.x64;
             return (uint)GetStructSize(typeof(T), Is64);
         }
@@ -208,6 +246,9 @@ namespace Brovan.Core.Emulation.OS
         /// <returns>return the size.</returns>
         public static int GetStructSize<[DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicFields | DynamicallyAccessedMemberTypes.NonPublicFields)] T>(bool Is64) where T : struct
         {
+            if (DirectSizeBool.TryGetValue(typeof(T), out Delegate Fast))
+                return ((Func<bool, int>)Fast)(Is64);
+
             return GetStructSize(typeof(T), Is64);
         }
 
@@ -232,6 +273,9 @@ namespace Brovan.Core.Emulation.OS
         /// <returns>Returns <see cref="WriteStructResult.Ok"/> on success, otherwise a failure result describing the error.</returns>
         public static WriteStructResult WriteStruct<[DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicFields | DynamicallyAccessedMemberTypes.NonPublicFields)] T>(BinaryEmulator Emulator, ulong Address, T Value) where T : struct
         {
+            if (DirectWrite.TryGetValue(typeof(T), out Delegate Fast))
+                return ((Func<BinaryEmulator, ulong, T, WriteStructResult>)Fast)(Emulator, Address, Value);
+
             if (Address == 0)
                 return WriteStructResult.Fail(WriteStructError.NullDestination, $"Destination address is NULL for {typeof(T).Name}");
 
@@ -293,6 +337,9 @@ namespace Brovan.Core.Emulation.OS
         /// <returns>Returns true if successful, otherwise false.</returns>
         public static bool ParseStruct<[DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicFields | DynamicallyAccessedMemberTypes.NonPublicFields)] T>(BinaryEmulator Emulator, ulong Address, out T Value) where T : struct
         {
+            if (DirectParseAddr.TryGetValue(typeof(T), out Delegate Fast))
+                return ((ParseStructAddrDelegate<T>)Fast)(Emulator, Address, out Value);
+
             Value = default;
             if (Address == 0) return false;
 
@@ -342,6 +389,9 @@ namespace Brovan.Core.Emulation.OS
         /// </remarks>
         public static bool ParseStruct<[DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicFields | DynamicallyAccessedMemberTypes.NonPublicFields)] T>(BinaryEmulator Emulator, byte[] Data, out T Value) where T : struct
         {
+            if (DirectParseBytes.TryGetValue(typeof(T), out Delegate Fast))
+                return ((ParseStructBytesDelegate<T>)Fast)(Emulator, Data, out Value);
+
             Value = default;
 
             bool Is64 = Emulator._binary.Architecture == BinaryArchitecture.x64;

Brovan/Core/Emulation/OS/Windows/Devices/ConsoleServer.cs

@@ -16,8 +16,9 @@ namespace Brovan.Core.Emulation.OS.Windows
         private const uint IoctlConDrvGetDisplayMode = 0x00500027;
         private const uint IoctlConDrvSetDisplayMode = 0x0050002B;
 
+        [GenerateStructSerializer]
         [StructLayout(LayoutKind.Explicit, Size = 0x30)]
-        private struct ConsoleApiMsgHeader
+        internal struct ConsoleApiMsgHeader
         {
             [FieldOffset(0x28)] public uint ApiNumber;
             [FieldOffset(0x2C)] public uint ApiDescriptorSize;

Brovan/Core/Emulation/OS/Windows/RPC/NtConnectPort.cs

@@ -8,7 +8,8 @@ namespace Brovan.Core.Emulation.OS.Windows
     internal class NtConnectPort : IWinSyscall
     {
         [StructLayout(LayoutKind.Sequential)]
-        private struct PORT_VIEW64
+        [GenerateStructSerializer]
+        internal struct PORT_VIEW64
         {
             public uint Length;
             public uint Padding0;
@@ -20,8 +21,9 @@ namespace Brovan.Core.Emulation.OS.Windows
             public ulong ViewRemoteBase;
         }
 
+        [GenerateStructSerializer]
         [StructLayout(LayoutKind.Sequential)]
-        private struct REMOTE_PORT_VIEW64
+        internal struct REMOTE_PORT_VIEW64
         {
             public uint Length;
             public uint Padding0;

Brovan/Core/Emulation/OS/Windows/Win32k/NtUserRegisterClassExWOW.cs

@@ -177,7 +177,8 @@ namespace Brovan.Core.Emulation.OS.Windows.Win32k
         }
 
         [StructLayout(LayoutKind.Explicit, Size = 80)]
-        private struct WNDCLASSEXW64
+        [GenerateStructSerializer]
+        internal struct WNDCLASSEXW64
         {
             [FieldOffset(0)] public uint cbSize;
             [FieldOffset(4)] public uint style;
@@ -193,8 +194,9 @@ namespace Brovan.Core.Emulation.OS.Windows.Win32k
             [FieldOffset(72)] public ulong hIconSm;
         }
 
+        [GenerateStructSerializer]
         [StructLayout(LayoutKind.Explicit, Size = 24)]
-        private struct CLSMENUNAME64
+        internal struct CLSMENUNAME64
         {
             [FieldOffset(0)] public ulong pszClientAnsiMenuName;
             [FieldOffset(8)] public ulong pwszClientUnicodeMenuName;

Brovan/Core/Emulation/OS/Windows/WinStructs.cs

@@ -9,6 +9,7 @@ using static System.Runtime.InteropServices.JavaScript.JSType;
 
 namespace Brovan.Core.Emulation.OS.Windows
 {
+    [GenerateStructSerializer]
     [StructLayout(LayoutKind.Explicit)]
     public struct UNICODE_STRING
     {
@@ -22,6 +23,7 @@ namespace Brovan.Core.Emulation.OS.Windows
         public uint Buffer;
     }
 
+    [GenerateStructSerializer]
     [StructLayout(LayoutKind.Explicit)]
     public struct UNICODE_STRING64
     {
@@ -35,6 +37,7 @@ namespace Brovan.Core.Emulation.OS.Windows
         public ulong Buffer;
     }
 
+    [GenerateStructSerializer]
     [StructLayout(LayoutKind.Explicit, Size = 48)]
     public struct OBJECT_ATTRIBUTES64
     {
@@ -57,6 +60,7 @@ namespace Brovan.Core.Emulation.OS.Windows
         public ulong SecurityQualityOfService;
     }
 
+    [GenerateStructSerializer]
     [StructLayout(LayoutKind.Sequential)]
     public struct MEMORY_REGION_INFORMATION
     {
@@ -69,6 +73,7 @@ namespace Brovan.Core.Emulation.OS.Windows
         public ulong NodePreference;
     }
 
+    [GenerateStructSerializer]
     [StructLayout(LayoutKind.Sequential)]
     public struct MEMORY_IMAGE_EXTENSION_INFORMATION
     {
@@ -78,6 +83,7 @@ namespace Brovan.Core.Emulation.OS.Windows
         public ulong ExtensionSize;
     }
 
+    [GenerateStructSerializer]
     [StructLayout(LayoutKind.Sequential)]
     public struct MEMORY_WORKING_SET_EX_INFORMATION
     {
@@ -154,6 +160,7 @@ namespace Brovan.Core.Emulation.OS.Windows
         public ulong Rip;
     }
 
+    [GenerateStructSerializer]
     [StructLayout(LayoutKind.Sequential)]
     public struct MEMORY_BASIC_INFORMATION
     {
@@ -169,6 +176,7 @@ namespace Brovan.Core.Emulation.OS.Windows
         public uint Reserved2; // tail padding to 48 bytes
     }
 
+    [GenerateStructSerializer]
     [StructLayout(LayoutKind.Sequential)]
     public struct MEMORY_IMAGE_INFORMATION
     {
@@ -217,6 +225,7 @@ namespace Brovan.Core.Emulation.OS.Windows
         MutantOwnerInformation = 1
     }
 
+    [GenerateStructSerializer]
     [StructLayout(LayoutKind.Sequential, Pack = 1)]
     public struct MUTANT_BASIC_INFORMATION
     {
@@ -231,6 +240,7 @@ namespace Brovan.Core.Emulation.OS.Windows
         SemaphoreBasicInformation = 0
     }
 
+    [GenerateStructSerializer]
     [StructLayout(LayoutKind.Sequential, Pack = 1)]
     public struct SEMAPHORE_BASIC_INFORMATION
     {
@@ -238,6 +248,7 @@ namespace Brovan.Core.Emulation.OS.Windows
         public int MaximumCount;
     }
 
+    [GenerateStructSerializer]
     [StructLayout(LayoutKind.Sequential, Pack = 1)]
     public struct OBJECT_BASIC_INFORMATION_DATA
     {
@@ -256,6 +267,7 @@ namespace Brovan.Core.Emulation.OS.Windows
         public long CreationTime;
     }
 
+    [GenerateStructSerializer]
     [StructLayout(LayoutKind.Sequential, Pack = 1)]
     public struct OBJECT_TYPE_INFORMATION64
     {
@@ -284,6 +296,7 @@ namespace Brovan.Core.Emulation.OS.Windows
         public uint DefaultNonPagedPoolCharge;
     }
 
+    [GenerateStructSerializer]
     [StructLayout(LayoutKind.Sequential, Pack = 1)]
     public struct OBJECT_TYPE_INFORMATION32
     {
@@ -312,6 +325,7 @@ namespace Brovan.Core.Emulation.OS.Windows
         public uint DefaultNonPagedPoolCharge;
     }
 
+    [GenerateStructSerializer]
     [StructLayout(LayoutKind.Explicit, Size = 16)]
     public struct LARGE_STRING64
     {
@@ -325,6 +339,7 @@ namespace Brovan.Core.Emulation.OS.Windows
         public ulong Buffer;
     }
 
+    [GenerateStructSerializer]
     [StructLayout(LayoutKind.Sequential)]
     public struct RECT
     {
@@ -334,6 +349,7 @@ namespace Brovan.Core.Emulation.OS.Windows
         public int Bottom;
     }
 
+    [GenerateStructSerializer]
     [StructLayout(LayoutKind.Sequential)]
     public struct SYSTEM_BATTERY_STATE
     {
@@ -361,6 +377,7 @@ namespace Brovan.Core.Emulation.OS.Windows
         public uint Capacity;
     }
 
+    [GenerateStructSerializer]
     [StructLayout(LayoutKind.Sequential)]
     public struct SYSTEM_POWER_CAPABILITIES
     {