- tweak: Some view change

Nebula.SourceGenerators/SourceHelper.cs

@@ -0,0 +1,56 @@
+using System.Text;
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.CSharp.Syntax;
+using Microsoft.CodeAnalysis.Text;
+
+namespace Nebula.SourceGenerators;
+
+public static class SourceHelper
+{
+    public static void GenerateAttribute(string attributeName, string usage,
+        IncrementalGeneratorInitializationContext context)
+    {
+        var attributeSourceCode = $@"// <auto-generated/>
+
+namespace SourceGen
+{{
+    [System.AttributeUsage(System.AttributeTargets.{usage})]
+    public class {attributeName} : System.Attribute
+    {{
+    }}
+}}";
+
+        context.RegisterPostInitializationOutput(ctx => ctx.AddSource(
+            $"{attributeName}.g.cs",
+            SourceText.From(attributeSourceCode, Encoding.UTF8)));
+    }
+    
+    public static bool HasAttribute(ISymbol type, string attributeName)
+    {
+        foreach (var attribute in type.GetAttributes())
+            if (attribute.AttributeClass?.ToDisplayString() == attributeName)
+                return true;
+
+        return false;
+    }
+
+    public static (ClassDeclarationSyntax, bool reportAttributeFound) GetClassDeclarationForSourceGen(
+        GeneratorSyntaxContext context, string AttributeName)
+    {
+        var classDeclarationSyntax = (ClassDeclarationSyntax)context.Node;
+
+        foreach (var attributeListSyntax in classDeclarationSyntax.AttributeLists)
+        foreach (var attributeSyntax in attributeListSyntax.Attributes)
+        {
+            if (context.SemanticModel.GetSymbolInfo(attributeSyntax).Symbol is not IMethodSymbol attributeSymbol)
+                continue;
+
+            var attributeName = attributeSymbol.ContainingType.ToDisplayString();
+
+            if (attributeName == AttributeName)
+                return (classDeclarationSyntax, true);
+        }
+
+        return (classDeclarationSyntax, false);
+    }
+}