Add new TransformFlags mod

This adds a "None = 0" member to Flags enums if they do not have an equivalent already

Author: Exanite

.silktouch/ce8a69a66cd3bd3f.stout

@@ -173,6 +173,7 @@
         "TransformHandles",
         "TransformFunctions",
         "TransformProperties",
+        "TransformFlags",
         "AddVTables"
       ],
       "ClangScraper": {

generator.json

@@ -26,6 +26,7 @@ public class ModLoader
             nameof(AddApiProfiles) => typeof(AddApiProfiles),
             nameof(MixKhronosData) => typeof(MixKhronosData),
             nameof(TransformHandles) => typeof(TransformHandles),
+            nameof(TransformFlags) => typeof(TransformFlags),
             nameof(ExtractNestedTyping) => typeof(ExtractNestedTyping),
             nameof(TransformProperties) => typeof(TransformProperties),
             nameof(ClangScraper) => typeof(ClangScraper),

sources/SilkTouch/SilkTouch/Mods/Common/ModLoader.cs

@@ -0,0 +1,80 @@
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.CSharp;
+using Microsoft.CodeAnalysis.CSharp.Syntax;
+using static Microsoft.CodeAnalysis.CSharp.SyntaxFactory;
+
+namespace Silk.NET.SilkTouch.Mods;
+
+/// <summary>
+/// Transforms [Flags] enums to have a "None = 0" member if they do not already have an equivalent.
+/// </summary>
+public class TransformFlags : IMod
+{
+    /// <inheritdoc />
+    public async Task ExecuteAsync(IModContext ctx, CancellationToken ct = default)
+    {
+        var proj = ctx.SourceProject;
+        if (proj == null)
+        {
+            return;
+        }
+
+        var compilation = await proj.GetCompilationAsync(ct);
+        if (compilation == null)
+        {
+            return;
+        }
+
+        var rewriter = new Rewriter(compilation);
+        foreach (var docId in proj?.DocumentIds ?? [])
+        {
+            var doc = proj!.GetDocument(docId) ?? throw new InvalidOperationException("Document missing");
+            proj = doc.WithSyntaxRoot(
+                rewriter.Visit(await doc.GetSyntaxRootAsync(ct))?.NormalizeWhitespace()
+                ?? throw new InvalidOperationException("Visit returned null.")
+            ).Project;
+        }
+
+        ctx.SourceProject = proj;
+    }
+
+    private class Rewriter(Compilation compilation) : CSharpSyntaxRewriter
+    {
+        public override SyntaxNode? VisitEnumDeclaration(EnumDeclarationSyntax node)
+        {
+            var isFlagsEnum = node.AttributeLists.SelectMany(list => list.Attributes)
+                .Any(attribute => attribute.IsAttribute("System.Flags"));
+
+            if (!isFlagsEnum)
+            {
+                return base.VisitEnumDeclaration(node);
+            }
+
+            var semanticModel = compilation.GetSemanticModel(node.SyntaxTree);
+            var symbol = semanticModel.GetDeclaredSymbol(node);
+            if (symbol == null)
+            {
+                return base.VisitEnumDeclaration(node);
+            }
+
+            // Add None member if it doesn't exist yet
+            var hasNoneMember = node.Members.Any(
+                member => member.Identifier.Text == "None"
+                          || (member.EqualsValue != null && semanticModel.GetConstantValue(member.EqualsValue.Value).Value is 0));
+
+            if (!hasNoneMember)
+            {
+                var noneMember = EnumMemberDeclaration("None")
+                    .WithEqualsValue(
+                        EqualsValueClause(
+                            LiteralExpression(SyntaxKind.NumericLiteralExpression, Literal(0))
+                        )
+                    );
+
+                node = node.WithMembers(node.Members.Insert(0, noneMember));
+            }
+
+            return base.VisitEnumDeclaration(node);
+        }
+    }
+}

sources/SilkTouch/SilkTouch/Mods/TransformFlags.cs

@@ -13,5 +13,6 @@ namespace Silk.NET.Vulkan;
 [Flags]
 public enum AccessFlags3KHR : ulong
 {
+    None = 0,
     Access3NoneKHR = unchecked((ulong)0UL),
 }

sources/Vulkan/Vulkan/Enums/AccessFlags3KHR.gen.cs

@@ -13,6 +13,7 @@ namespace Silk.NET.Vulkan;
 [Flags]
 public enum BufferUsageFlags2 : ulong
 {
+    None = 0,
     TransferSrcBit = unchecked((ulong)0x00000001UL),
     TransferDstBit = unchecked((ulong)0x00000002UL),
     UniformTexelBufferBit = unchecked((ulong)0x00000004UL),

sources/Vulkan/Vulkan/Enums/BufferUsageFlags2.gen.cs

@@ -11,4 +11,7 @@ namespace Silk.NET.Vulkan;
 
 [Transformed]
 [Flags]
-public enum ExportMetalObjectTypeFlagsEXT : uint { }
+public enum ExportMetalObjectTypeFlagsEXT : uint
+{
+    None = 0,
+}

sources/Vulkan/Vulkan/Enums/ExportMetalObjectTypeFlagsEXT.gen.cs

@@ -13,6 +13,7 @@ namespace Silk.NET.Vulkan;
 [Flags]
 public enum FormatFeatureFlags2 : ulong
 {
+    None = 0,
     SampledImageBit = unchecked((ulong)0x00000001UL),
     StorageImageBit = unchecked((ulong)0x00000002UL),
     StorageImageAtomicBit = unchecked((ulong)0x00000004UL),

sources/Vulkan/Vulkan/Enums/FormatFeatureFlags2.gen.cs

@@ -11,4 +11,7 @@ namespace Silk.NET.Vulkan;
 
 [Transformed]
 [Flags]
-public enum ImageConstraintsInfoFlagsFuchsia : uint { }
+public enum ImageConstraintsInfoFlagsFuchsia : uint
+{
+    None = 0,
+}

sources/Vulkan/Vulkan/Enums/ImageConstraintsInfoFlagsFuchsia.gen.cs

@@ -13,5 +13,6 @@ namespace Silk.NET.Vulkan;
 [Flags]
 public enum MemoryDecompressionMethodFlagsNV : ulong
 {
+    None = 0,
     Gdeflate1X0BitNV = unchecked((ulong)0x00000001UL),
 }