Add support for marking methods as manual imports and fixing the PInvokeGeneratorConfiguration to be more forward compatible

sources/ClangSharp.PInvokeGenerator/Abstractions/FunctionOrDelegateDesc.cs

@@ -50,6 +50,21 @@ public bool IsDllImport
             }
         }
 
+        public bool IsManualImport
+        {
+            get
+            {
+                return (Flags & FunctionOrDelegateFlags.IsManualImport) != 0;
+            }
+
+            set
+            {
+                Flags = value
+                      ? Flags | FunctionOrDelegateFlags.IsManualImport
+                      : Flags & ~FunctionOrDelegateFlags.IsManualImport;
+            }
+        }
+
         public bool HasFnPtrCodeGen
         {
             get

sources/ClangSharp.PInvokeGenerator/Abstractions/IOutputBuilder.VisitDecl.cs

@@ -30,13 +30,13 @@ internal partial interface IOutputBuilder
         void EndField(in FieldDesc desc);
 
         void BeginFunctionOrDelegate(in FunctionOrDelegateDesc info, ref bool isMethodClassUnsafe);
-        void BeginFunctionInnerPrototype(string escapedName);
+        void BeginFunctionInnerPrototype(in FunctionOrDelegateDesc info);
         void BeginParameter(in ParameterDesc info);
         void BeginParameterDefault();
         void EndParameterDefault();
         void EndParameter(in ParameterDesc info);
         void WriteParameterSeparator();
-        void EndFunctionInnerPrototype();
+        void EndFunctionInnerPrototype(in FunctionOrDelegateDesc info);
         void BeginConstructorInitializer(string memberRefName, string memberInitName);
         void EndConstructorInitializer();
         void BeginBody(bool isExpressionBody = false);

sources/ClangSharp.PInvokeGenerator/Abstractions/ParameterDesc.cs

@@ -15,5 +15,6 @@ internal struct ParameterDesc
         public Action<object> WriteCustomAttrs { get; set; }
         public object CustomAttrGeneratorData { get; set; }
         public CXSourceLocation? Location { get; set; }
+        public bool IsForManualImport { get; set; }
     }
 }

sources/ClangSharp.PInvokeGenerator/CSharp/CSharpOutputBuilder.VisitDecl.cs

@@ -373,7 +373,7 @@ public void BeginFunctionOrDelegate(in FunctionOrDelegateDesc desc, ref bool isM
 
                 WriteLine(']');
             }
-            else if (desc.IsDllImport)
+            else if (desc.IsDllImport && !desc.IsManualImport)
             {
                 AddUsingDirective("System.Runtime.InteropServices");
 
@@ -418,7 +418,6 @@ public void BeginFunctionOrDelegate(in FunctionOrDelegateDesc desc, ref bool isM
             {
                 WriteIndentedLine("[SetsLastSystemError]");
             }
-            // GenerateSetsLastSystemErrorAttribute
 
             if (desc.IsAggressivelyInlined)
             {
@@ -433,7 +432,7 @@ public void BeginFunctionOrDelegate(in FunctionOrDelegateDesc desc, ref bool isM
                 AddVtblIndexAttribute(vtblIndex);
             }
 
-            if (desc.NativeTypeName is not null)
+            if ((desc.NativeTypeName is not null) && !desc.IsManualImport)
             {
                 AddNativeTypeNameAttribute(desc.NativeTypeName, attributePrefix: "return: ");
             }
@@ -460,7 +459,7 @@ public void BeginFunctionOrDelegate(in FunctionOrDelegateDesc desc, ref bool isM
                     }
                     Write("delegate ");
                 }
-                else if (desc.IsStatic ?? (desc.IsDllImport || !desc.IsCxx))
+                else if ((desc.IsStatic ?? (desc.IsDllImport || !desc.IsCxx)) && !desc.IsManualImport)
                 {
                     Write("static ");
 
@@ -473,28 +472,25 @@ public void BeginFunctionOrDelegate(in FunctionOrDelegateDesc desc, ref bool isM
 
             if (!desc.IsVirtual)
             {
-                //if (NeedsNewKeyword(escapedName, functionDecl.Parameters))
                 if (desc.NeedsNewKeyword)
                 {
                     Write("new ");
                 }
 
                 if (desc.IsUnsafe)
                 {
-                    //if (cxxRecordDecl is null)
                     if (!desc.IsCtxCxxRecord)
                     {
                         isMethodClassUnsafe = true;
                     }
-                    //else if (!IsUnsafe(cxxRecordDecl))
                     else if (!desc.IsCxxRecordCtxUnsafe)
                     {
                         Write("unsafe ");
                     }
                 }
             }
 
-            if (!desc.IsCxxConstructor)
+            if (!desc.IsCxxConstructor && !desc.IsManualImport)
             {
                 Write(desc.ReturnType);
                 Write(' ');
@@ -532,35 +528,59 @@ private void WriteSourceLocation(CXSourceLocation location, bool inline)
             }
         }
 
-        public void BeginFunctionInnerPrototype(string escapedName)
+        public void BeginFunctionInnerPrototype(in FunctionOrDelegateDesc desc)
         {
-            Write(escapedName);
-            Write('(');
+            if (desc.IsManualImport)
+            {
+                Write("delegate* unmanaged");
+
+                if (desc.CallingConvention != CallingConvention.Winapi)
+                {
+                    Write('[');
+                    Write(desc.CallingConvention);
+                    Write(']');
+                }
+
+                Write('<');
+            }
+            else
+            {
+                Write(desc.EscapedName);
+                Write('(');
+            }
         }
 
         public void BeginParameter(in ParameterDesc info)
         {
-            if (info.NativeTypeName is not null)
+            if (info.IsForManualImport)
             {
-                AddNativeTypeNameAttribute(info.NativeTypeName, prefix: "", postfix: " ");
+                Write(info.Type);
             }
-
-            if (info.CppAttributes is not null)
+            else
             {
-                AddCppAttributes(info.CppAttributes, prefix: "", postfix: " ");
-            }
+                if (info.NativeTypeName is not null)
+                {
+                    AddNativeTypeNameAttribute(info.NativeTypeName, prefix: "", postfix: " ");
+                }
 
-            if (info.Location is {} location)
-            {
-                WriteSourceLocation(location, true);
-            }
+                if (info.CppAttributes is not null)
+                {
+                    AddCppAttributes(info.CppAttributes, prefix: "", postfix: " ");
+                }
 
-            _customAttrIsForParameter = true;
-            info.WriteCustomAttrs?.Invoke(info.CustomAttrGeneratorData);
-            _customAttrIsForParameter = false;
-            Write(info.Type);
-            Write(' ');
-            Write(info.Name);
+                if (info.Location is { } location)
+                {
+                    WriteSourceLocation(location, true);
+                }
+
+                _customAttrIsForParameter = true;
+                info.WriteCustomAttrs?.Invoke(info.CustomAttrGeneratorData);
+                _customAttrIsForParameter = false;
+
+                Write(info.Type);
+                Write(' ');
+                Write(info.Name);
+            }
         }
 
         public void BeginParameterDefault() => Write(" = ");
@@ -581,7 +601,18 @@ public void WriteParameterSeparator()
             Write(' ');
         }
 
-        public void EndFunctionInnerPrototype() => Write(')');
+        public void EndFunctionInnerPrototype(in FunctionOrDelegateDesc desc)
+        {
+            if (desc.IsManualImport)
+            {
+                Write(desc.ReturnType);
+                Write('>');
+            }
+            else
+            {
+                Write(')');
+            }
+        }
 
         public void BeginConstructorInitializer(string memberRefName, string memberInitName)
         {
@@ -646,6 +677,12 @@ public void EndBody(bool isExpressionBody = false)
 
         public void EndFunctionOrDelegate(in FunctionOrDelegateDesc desc)
         {
+            if (desc.IsManualImport)
+            {
+                Write(' ');
+                Write(desc.EscapedName);
+            }
+
             if (!desc.HasBody || desc.IsVirtual)
             {
                 WriteSemicolon();

sources/ClangSharp.PInvokeGenerator/ClangSharp.PInvokeGenerator.csproj

@@ -3,7 +3,7 @@
 
   <PropertyGroup>
     <RootNamespace>ClangSharp</RootNamespace>
-    <TargetFrameworks>net6.0;netstandard2.0</TargetFrameworks>
+    <TargetFrameworks>net6.0</TargetFrameworks>
   </PropertyGroup>
 
   <ItemGroup>

sources/ClangSharp.PInvokeGenerator/FunctionOrDelegateFlags.cs

@@ -1,4 +1,4 @@
-using System;
+using System;
 
 namespace ClangSharp
 {
@@ -20,5 +20,6 @@ public enum FunctionOrDelegateFlags
         IsNotStatic = 1 << 12,
         NeedsReturnFixup = 1 << 13,
         IsCxxConstructor = 1 << 14,
+        IsManualImport = 1 << 15,
     }
 }