Checkpoint

Alpm/Interop/CFormatter.cs

@@ -0,0 +1,88 @@
+using System;
+using System.Buffers;
+using System.Runtime.InteropServices;
+using System.Text;
+
+namespace Foodsoft.Alpm.Interop
+{
+    internal static class CFormatter
+    {
+        private static readonly int vaListCopyNWords;
+
+        private static readonly Vsnprintf? vsnprintfFunc;
+
+        static CFormatter()
+        {
+            if (RuntimeInformation.IsOSPlatform(OSPlatform.Linux) ||
+                RuntimeInformation.IsOSPlatform(OSPlatform.FreeBSD))
+            {
+                vaListCopyNWords = RuntimeInformation.ProcessArchitecture switch
+                {
+                    Architecture.X86 => 1,
+                    Architecture.X64 => 3,
+                    Architecture.Arm => 1,
+                    Architecture.Arm64 => 4,
+                    _ => vaListCopyNWords
+                };
+                vsnprintfFunc = vsnprintfLibc;
+            }
+            else if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+            {
+                vaListCopyNWords = 1;
+                vsnprintfFunc = vsnprintfUCrt;
+            }
+            else if (RuntimeInformation.IsOSPlatform(OSPlatform.OSX))
+            {
+                vaListCopyNWords = RuntimeInformation.ProcessArchitecture switch
+                {
+                    Architecture.X86 => 1,
+                    Architecture.X64 => 3,
+                    Architecture.Arm => 1,
+                    Architecture.Arm64 => 1,
+                    _ => vaListCopyNWords
+                };
+                vsnprintfFunc = vsnprintfLibc;
+            }
+        }
+
+        internal static unsafe string Format(IntPtr format, IntPtr vaList)
+        {
+            const int bufSize = 256;
+            if (vsnprintfFunc == null || vaListCopyNWords <= 0)
+                return "[Formatter unsupported for platform]";
+
+            var vaListBuf = (void**) vaList;
+            var vaListCopy = stackalloc void*[vaListCopyNWords];
+            for (var i = 0; i < vaListCopyNWords; i++) vaListCopy[i] = vaListBuf[i];
+            
+            var strBuf = stackalloc byte[bufSize];
+            var strBufPtr = (IntPtr) strBuf;
+            
+            var nbNeed = vsnprintfFunc(strBufPtr, (UIntPtr) bufSize, format, vaList);
+
+            if (nbNeed < bufSize)
+                return Marshal.PtrToStringUTF8(strBufPtr, nbNeed);
+
+            var pool = ArrayPool<byte>.Shared;
+
+            var buffer = pool.Rent(nbNeed + 1);
+            fixed (byte* pb = buffer)
+            {
+                nbNeed = vsnprintfFunc((IntPtr) pb, (UIntPtr) buffer.Length, format, (IntPtr) vaListCopy);
+            }
+
+            var result = Encoding.UTF8.GetString(buffer, 0, nbNeed);
+            pool.Return(buffer);
+            return result;
+        }
+
+        private delegate int Vsnprintf(IntPtr buffer, UIntPtr size, IntPtr format, IntPtr args);
+
+        
+        [DllImport("libc", EntryPoint = "vsnprintf", CallingConvention = CallingConvention.Cdecl)]
+        internal static extern int vsnprintfLibc(IntPtr buffer, UIntPtr size, IntPtr format, IntPtr args);
+
+        [DllImport("ucrt", EntryPoint = "vsnprintf", CallingConvention = CallingConvention.Cdecl)]
+        internal static extern int vsnprintfUCrt(IntPtr buffer, UIntPtr size, IntPtr format, IntPtr args);
+    }
+}

Alpm/Interop/UTF8In.cs

@@ -0,0 +1,42 @@
+using System;
+using System.Diagnostics.CodeAnalysis;
+using System.Runtime.InteropServices;
+using JetBrains.Annotations;
+
+namespace Foodsoft.Alpm.Marshalling
+{
+    internal readonly struct UTF8In : ICustomMarshaler
+    {
+        private static readonly UTF8In _instance = default;
+
+        public void CleanUpManagedData(object managedObj) { }
+
+        public void CleanUpNativeData(IntPtr pNativeData)
+        {
+            if (pNativeData == IntPtr.Zero)
+                return;
+            Marshal.FreeCoTaskMem(pNativeData);
+        }
+
+        public int GetNativeDataSize()
+        {
+            return -1;
+        }
+
+        public IntPtr MarshalManagedToNative(object? managedObj)
+        {
+            return Marshal.StringToCoTaskMemUTF8((string?) managedObj);
+        }
+
+        public object MarshalNativeToManaged(IntPtr pNativeData)
+        {
+            return Marshal.PtrToStringUTF8(pNativeData)!;
+        }
+        
+        [UsedImplicitly]
+        private static ICustomMarshaler GetInstance(string cookie)
+        {
+            return _instance;
+        }
+    }
+}

Alpm/Interop/UTF8Return.cs

@@ -0,0 +1,36 @@
+using System;
+using System.Runtime.InteropServices;
+using JetBrains.Annotations;
+
+namespace Foodsoft.Alpm.Marshalling
+{
+    internal readonly struct UTF8Return : ICustomMarshaler
+    {
+        private static readonly UTF8Return _instance = default;
+
+        [UsedImplicitly]
+        private static ICustomMarshaler GetInstance(string cookie)
+        {
+            return _instance;
+        }
+
+        public void CleanUpManagedData(object managedObj) { }
+
+        public void CleanUpNativeData(IntPtr pNativeData) { }
+
+        public int GetNativeDataSize()
+        {
+            return -1;
+        }
+
+        public object MarshalNativeToManaged(IntPtr pNativeData)
+        {
+            return Marshal.PtrToStringUTF8(pNativeData)!;
+        }
+
+        public IntPtr MarshalManagedToNative(object managedObj)
+        {
+            throw new NotImplementedException();
+        }
+    }
+}