Enable nullable reference types and update nullability; fix several null checks

Fully enable nullable reference types and update method signatures, fields, and events to use nullable annotations throughout the codebase. Methods now return null instead of empty arrays/strings where appropriate. Private parameterless constructors now throw NotImplementedException to prevent misuse. Improves null-safety, code clarity, and robustness against null reference exceptions.

Author: lone7254

src/VmmSharpEx/Extensions/Input/VmmInputManager.cs

@@ -48,7 +48,7 @@ public sealed class VmmInputManager
         private readonly ulong _gafAsyncKeyStateExport;
         private readonly uint _winLogonPid;
 
-        private VmmInputManager() { }
+        private VmmInputManager() { throw new NotImplementedException(); }
 
         /// <summary>
         /// Extension class that queries user input state via Win32 Kernel Interop (Read-Only).
@@ -64,6 +64,8 @@ public VmmInputManager(Vmm vmm)
             if (!_vmm.PidGetFromName("winlogon.exe", out _winLogonPid))
                 throw new VmmException("Failed to get winlogon.exe PID");
             var pids = _vmm.PidGetAllFromName("csrss.exe");
+            if (pids is null || pids.Length == 0)
+                throw new VmmException("Failed to get csrss.exe PIDs");
             ulong gafAsyncKeyStateExport = 0;
 
             var exceptions = new List<Exception>();

src/VmmSharpEx/Extensions/VmmExtensions.cs

@@ -76,7 +76,7 @@ public static bool IsValidKernelVA(this ulong va) =>
         /// <param name="paramName">Parameter name for the exception message.</param>
         /// <exception cref="VmmException"></exception>
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public static void ThrowIfInvalidVA(this ulong va, string paramName = null)
+        public static void ThrowIfInvalidVA(this ulong va, string? paramName = null)
         {
             if (!VmmUtilities.IsValidVA(va))
                 throw new VmmException(paramName is null ?
@@ -91,7 +91,7 @@ public static void ThrowIfInvalidVA(this ulong va, string paramName = null)
         /// <param name="paramName">Parameter name for the exception message.</param>
         /// <exception cref="VmmException"></exception>
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public static void ThrowIfInvalidUserVA(this ulong va, string paramName = null)
+        public static void ThrowIfInvalidUserVA(this ulong va, string? paramName = null)
         {
             if (!VmmUtilities.IsValidUserVA(va))
                 throw new VmmException(paramName is null ?
@@ -106,7 +106,7 @@ public static void ThrowIfInvalidUserVA(this ulong va, string paramName = null)
         /// <param name="paramName">Parameter name for the exception message.</param>
         /// <exception cref="VmmException"></exception>
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public static void ThrowIfInvalidKernelVA(this ulong va, string paramName = null)
+        public static void ThrowIfInvalidKernelVA(this ulong va, string? paramName = null)
         {
             if (!VmmUtilities.IsValidKernelVA(va))
                 throw new VmmException(paramName is null ?
@@ -145,7 +145,7 @@ public static bool FixCr3(this Vmm vmm, string processName, uint pid)
             while (true)
             {
                 var percentBytes = vmm.VfsRead(@"\misc\procinfo\progress_percent.txt", 4);
-                if (percentBytes.Length > 0 &&
+                if (percentBytes is not null &&
                     int.TryParse(Encoding.ASCII.GetString(percentBytes).Trim(), out int percent) &&
                     percent == 100)
                     break;
@@ -154,9 +154,9 @@ public static bool FixCr3(this Vmm vmm, string processName, uint pid)
             }
 
             // VFS list and read DTBs
-            var vfsEntries = vmm.VfsList(@"\misc\procinfo\");
+            //var vfsEntries = vmm.VfsList(@"\misc\procinfo\");
             var dtbRaw = vmm.VfsRead(@"\misc\procinfo\dtb.txt", 0x1000);
-            if (dtbRaw.Length == 0)
+            if (dtbRaw is null)
                 return false;
 
             var possibleDtbs = new List<ulong>();

src/VmmSharpEx/LeechCore.cs

@@ -38,11 +38,12 @@ public sealed class LeechCore : IDisposable
     private readonly Vmm _parent;
     private IntPtr _handle;
 
-    private LeechCore() { }
+    private LeechCore() { throw new NotImplementedException(); }
 
     private LeechCore(IntPtr hLC)
     {
         _handle = hLC;
+        _parent = null!;  // Required for nullable, but will be set in internal constructor
     }
 
     /// <summary>
@@ -120,7 +121,7 @@ public override string ToString()
     /// <param name="pLcCreateConfig">The LC configuration to use.</param>
     /// <param name="configErrorInfo">Receives extended create-time error information, if available.</param>
     /// <returns>An initialized <see cref="LeechCore"/> instance on success; otherwise <see langword="null"/>.</returns>
-    public static unsafe LeechCore Create(ref LCConfig pLcCreateConfig, out LCConfigErrorInfo configErrorInfo)
+    public static unsafe LeechCore? Create(ref LCConfig pLcCreateConfig, out LCConfigErrorInfo configErrorInfo)
     {
         var cbERROR_INFO = Marshal.SizeOf<Lci.LC_CONFIG_ERRORINFO>();
         var pLcCreateConfigNative = Marshal.AllocHGlobal(Marshal.SizeOf<LCConfig>());
@@ -151,7 +152,7 @@ public static unsafe LeechCore Create(ref LCConfig pLcCreateConfig, out LCConfig
                     configErrorInfo.fUserInputRequest = e.fUserInputRequest;
                     if (e.cwszUserText > 0)
                     {
-                        configErrorInfo.strUserText = Marshal.PtrToStringUni((IntPtr)(pLcErrorInfo.ToInt64() + cbERROR_INFO));
+                        configErrorInfo.strUserText = Marshal.PtrToStringUni((IntPtr)(pLcErrorInfo.ToInt64() + cbERROR_INFO)) ?? "";
                     }
                 }
 
@@ -193,7 +194,7 @@ private void Dispose(bool disposing)
     /// <param name="pa">Physical address to read from.</param>
     /// <param name="cb">Count of bytes to read.</param>
     /// <returns>A byte array with the read memory, otherwise <see langword="null"/>.</returns>
-    public unsafe byte[] Read(ulong pa, uint cb)
+    public unsafe byte[]? Read(ulong pa, uint cb)
     {
         var arr = new byte[cb];
         fixed (byte* pb = arr)
@@ -235,7 +236,7 @@ public unsafe bool ReadValue<T>(ulong pa, out T result)
     /// <param name="pa">Physical address to read.</param>
     /// <param name="count">Number of elements to read.</param>
     /// <returns>An array on success; otherwise <see langword="null"/>.</returns>
-    public unsafe T[] ReadArray<T>(ulong pa, int count)
+    public unsafe T[]? ReadArray<T>(ulong pa, int count)
         where T : unmanaged
     {
         var arr = new T[count];
@@ -257,7 +258,7 @@ public unsafe T[] ReadArray<T>(ulong pa, int count)
     /// <param name="pa">Physical address to read.</param>
     /// <param name="count">Number of elements to read.</param>
     /// <returns>A <see cref="IMemoryOwner{T}"/> lease on success; otherwise <see langword="null"/>. Be sure to call <see cref="IDisposable.Dispose()"/> when done.</returns>
-    public unsafe IMemoryOwner<T> ReadPooled<T>(ulong pa, int count)
+    public unsafe IMemoryOwner<T>? ReadPooled<T>(ulong pa, int count)
         where T : unmanaged
     {
         var arr = new PooledMemory<T>(count);
@@ -474,7 +475,7 @@ public bool SetOption(LcOption fOption, ulong qwValue)
     /// <param name="dataIn">Optional input data.</param>
     /// <param name="dataOut">Receives any output data returned by the command.</param>
     /// <returns><see langword="true"/> on success; otherwise <see langword="false"/>.</returns>
-    public unsafe bool ExecuteCommand(LcCmd fOption, ReadOnlySpan<byte> dataIn, out byte[] dataOut)
+    public unsafe bool ExecuteCommand(LcCmd fOption, ReadOnlySpan<byte> dataIn, out byte[]? dataOut)
     {
         uint cbDataOut;
         IntPtr pbDataOut;
@@ -512,15 +513,18 @@ public unsafe bool ExecuteCommand(LcCmd fOption, ReadOnlySpan<byte> dataIn, out
     /// Wraps native memory returned from a scatter read invocation.
     /// </summary>
     /// <remarks>
-    /// The underlying native scatter page buffers are released via <see cref="Lci.LcMemFree(IntPtr)"/> when this handle
+    /// The underlying native scatter page buffers are released via <see cref="Lci.LcMemFree(void*)"/> when this handle
     /// is disposed.
     /// </remarks>
     public sealed class LcScatterHandle : IDisposable
     {
         private readonly PooledDictionary<ulong, ScatterData> _results;
         private IntPtr _mems;
 
-        private LcScatterHandle() { }
+        private LcScatterHandle()
+        {
+            _results = new PooledDictionary<ulong, ScatterData>();
+        }
 
         internal LcScatterHandle(PooledDictionary<ulong, ScatterData> results, IntPtr mems)
         {
@@ -648,7 +652,7 @@ public struct LcMemScatter
         /// A read-only view over the page contents pointed at by <see cref="pb"/>.
         /// </summary>
         /// <remarks>
-        /// DANGER: Do not access this memory after the memory is freed via <see cref="Lci.LcMemFree(IntPtr)"/>.
+        /// DANGER: Do not access this memory after the memory is freed via <see cref="Lci.LcMemFree(void*)"/>.
         /// </remarks>
         public readonly unsafe ReadOnlySpan<byte> Data =>
             new ReadOnlySpan<byte>(pb.ToPointer(), checked((int)cb));
@@ -730,7 +734,7 @@ public struct LCConfigErrorInfo
         /// <summary>
         /// Optional user text provided by the native layer.
         /// </summary>
-        public string strUserText;
+        public string? strUserText;
     }
 
     #endregion

src/VmmSharpEx/Scatter/VmmScatter.cs

@@ -60,7 +60,7 @@ private set
     /// <summary>
     /// Event is fired upon completion of <see cref="Execute"/>. Exceptions are handled/ignored.
     /// </summary>
-    public event EventHandler<VmmScatter> Completed;
+    public event EventHandler<VmmScatter>? Completed;
     private void OnCompleted()
     {
         foreach (var callback in Completed?.GetInvocationList() ?? Enumerable.Empty<Delegate>())
@@ -73,7 +73,7 @@ private void OnCompleted()
         }
     }
 
-    private VmmScatter() { }
+    private VmmScatter() { throw new NotImplementedException(); }
 
     internal VmmScatter(Vmm vmm, uint pid, VmmFlags flags = VmmFlags.NONE)
     {
@@ -280,7 +280,7 @@ public void Execute()
     /// <param name="cb">Count of bytes to be read.</param>
     /// <param name="cbRead">Count of bytes actually read.</param>
     /// <returns>A byte array with the read memory, otherwise <see langword="null"/>. Be sure to also check <paramref name="cbRead"/>.</returns>
-    public unsafe byte[] Read(ulong address, uint cb, out uint cbRead)
+    public unsafe byte[]? Read(ulong address, uint cb, out uint cbRead)
     {
         var arr = new byte[cb];
         fixed (byte* pb = arr)
@@ -374,7 +374,7 @@ public bool ReadPtr(ulong address, out VmmPointer result)
     /// <param name="address">Address to read from.</param>
     /// <param name="count">The number of array elements to read.</param>
     /// <returns>An array on success; otherwise <see langword="null"/>.</returns>
-    public unsafe T[] ReadArray<T>(ulong address, int count)
+    public unsafe T[]? ReadArray<T>(ulong address, int count)
         where T : unmanaged
     {
         uint cb = checked((uint)sizeof(T) * (uint)count);
@@ -399,7 +399,7 @@ public unsafe T[] ReadArray<T>(ulong address, int count)
     /// <param name="address">Address to read from.</param>
     /// <param name="count">The number of array elements to read.</param>
     /// <returns><see cref="IMemoryOwner{T}"/> lease, or <see langword="null"/> if failed. Be sure to call <see cref="IDisposable.Dispose()"/> when done.</returns>
-    public unsafe IMemoryOwner<T> ReadPooled<T>(ulong address, int count)
+    public unsafe IMemoryOwner<T>? ReadPooled<T>(ulong address, int count)
         where T : unmanaged
     {
         uint cb = checked((uint)sizeof(T) * (uint)count);
@@ -445,10 +445,10 @@ public unsafe bool ReadSpan<T>(ulong address, Span<T> span)
     /// <param name="cb">Count of bytes to read. Keep in mind some string encodings are 2-4 bytes per character.</param>
     /// <param name="encoding">String Encoding for this read.</param>
     /// <returns>C# Managed <see cref="System.String"/>. Otherwise, <see langword="null"/> if failed.</returns>
-    public string ReadString(ulong address, int cb, Encoding encoding)
+    public string? ReadString(ulong address, int cb, Encoding encoding)
     {
-        byte[] rentedBytes = null;
-        char[] rentedChars = null;
+        byte[]? rentedBytes = null;
+        char[]? rentedChars = null;
         try
         {
             Span<byte> bytesSource = cb <= 256 ?
@@ -495,7 +495,7 @@ public void Clear(VmmFlags? flags = null, uint? pid = null)
         if (pid is uint p)
             _pid = p;
         _isPrepared = default;
-        Completed = default;
+        Completed = null;
         if (!Vmmi.VMMDLL_Scatter_Clear(_handle, _pid, _flags))
             throw new VmmException("Failed to clear VmmScatter Handle.");
     }

src/VmmSharpEx/Scatter/VmmScatterMap.cs

@@ -24,10 +24,10 @@ public sealed class VmmScatterMap : IDisposable
         /// <summary>
         /// Event is fired upon completion of <see cref="Execute"/>.
         /// </summary>
-        public event EventHandler Completed;
+        public event EventHandler? Completed;
         private void OnCompleted() => Completed?.Invoke(this, EventArgs.Empty);
 
-        private VmmScatterMap() { }
+        private VmmScatterMap() { throw new NotImplementedException(); }
 
         internal VmmScatterMap(Vmm vmm, uint pid)
         {