Migrate to incremental generator

DecoratorGenerator.UnitTests/CSharpSourceGeneratorVerifier.cs

@@ -6,7 +6,7 @@
 
 namespace DecoratorGenerator.UnitTests;
 
-public static class CSharpSourceGeneratorVerifier<TSourceGenerator> where TSourceGenerator : ISourceGenerator, new()
+public static class CSharpSourceGeneratorVerifier<TSourceGenerator> where TSourceGenerator : IIncrementalGenerator, new()
 {
     public class Test : CSharpSourceGeneratorTest<TSourceGenerator, DefaultVerifier>
     {

DecoratorGenerator.UnitTests/DecoratorGenerator.UnitTests.csproj

@@ -11,17 +11,17 @@
 
   <ItemGroup>
     <PackageReference Include="AWSSDK.DynamoDBv2" Version="3.7.103.8" />
-    <PackageReference Include="Microsoft.CodeAnalysis.CSharp" Version="4.9.2" />
-    <PackageReference Include="Microsoft.CodeAnalysis.CSharp.SourceGenerators.Testing.NUnit" Version="1.1.1" />
-    <PackageReference Include="Microsoft.CodeAnalysis.CSharp.Workspaces" Version="4.9.2" />
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.10.0" />
-    <PackageReference Include="NUnit" Version="4.1.0" />
-    <PackageReference Include="NUnit3TestAdapter" Version="4.5.0" />
-    <PackageReference Include="NUnit.Analyzers" Version="4.2.0">
+    <PackageReference Include="Microsoft.CodeAnalysis.CSharp" Version="5.0.0" />
+    <PackageReference Include="Microsoft.CodeAnalysis.CSharp.SourceGenerators.Testing" Version="1.1.2" />
+    <PackageReference Include="Microsoft.CodeAnalysis.CSharp.Workspaces" Version="5.0.0" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.0.1" />
+    <PackageReference Include="NUnit" Version="4.4.0" />
+    <PackageReference Include="NUnit3TestAdapter" Version="5.2.0" />
+    <PackageReference Include="NUnit.Analyzers" Version="4.11.2">
       <PrivateAssets>all</PrivateAssets>
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
     </PackageReference>
-    <PackageReference Include="coverlet.collector" Version="6.0.2">
+    <PackageReference Include="coverlet.collector" Version="6.0.4">
       <PrivateAssets>all</PrivateAssets>
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
     </PackageReference>

DecoratorGenerator/DecoratorGenerator.csproj

@@ -54,13 +54,13 @@
     </ItemGroup>
 
     <ItemGroup>
-        <PackageReference Include="Microsoft.CodeAnalysis.Analyzers" Version="3.3.4">
+        <PackageReference Include="Microsoft.CodeAnalysis.Analyzers" Version="3.11.0">
             <PrivateAssets>all</PrivateAssets>
             <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
         </PackageReference>
-        <PackageReference Include="Microsoft.CodeAnalysis.Common" Version="4.9.2" />
-        <PackageReference Include="Microsoft.CodeAnalysis.CSharp" Version="4.9.2" />
-        <PackageReference Include="Microsoft.CodeAnalysis.NetAnalyzers" Version="8.0.0">
+        <PackageReference Include="Microsoft.CodeAnalysis.Common" Version="5.0.0" />
+        <PackageReference Include="Microsoft.CodeAnalysis.CSharp" Version="5.0.0" />
+        <PackageReference Include="Microsoft.CodeAnalysis.NetAnalyzers" Version="10.0.100">
             <PrivateAssets>all</PrivateAssets>
             <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
         </PackageReference>

DecoratorGenerator/Main.cs

@@ -1,42 +1,61 @@
 using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.CSharp.Syntax;
 using Microsoft.CodeAnalysis.Text;
 using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Text;
+using System.Threading;
 
 namespace DecoratorGenerator
 {
     [Generator]
-    public class Main : ISourceGenerator
+    public class Main : IIncrementalGenerator
     {
-        public void Initialize(GeneratorInitializationContext context) {
-            // No initialization required for this one
+        public void Initialize(IncrementalGeneratorInitializationContext context) {
+            var types = context.SyntaxProvider.ForAttributeWithMetadataName(
+                $"DecoratorGenerator.{nameof(DecorateAttribute)}",
+                predicate: IsSyntaxTargetForGeneration,
+                transform: GetSemanticTargetForGeneration
+            );
+
+            var thirdPartyTypes = context.CompilationProvider.SelectMany(GetThirdPartySemanticTargetsForGeneration);
+
+            context.RegisterSourceOutput(types, Execute);
+            context.RegisterSourceOutput(thirdPartyTypes, Execute);
+        }
+
+        private static bool IsSyntaxTargetForGeneration(SyntaxNode syntaxNode, CancellationToken token) {
+            return syntaxNode is InterfaceDeclarationSyntax;
         }
 
-        public void Execute(GeneratorExecutionContext context) {
-            var types = GetAllDecoratedTypes(context.Compilation.Assembly.GlobalNamespace);
+        private static INamedTypeSymbol GetSemanticTargetForGeneration(GeneratorAttributeSyntaxContext context, CancellationToken cancellationToken) {
+            var intefaceSyntax = context.TargetNode as InterfaceDeclarationSyntax;
+            var symbol = context.SemanticModel.GetDeclaredSymbol(intefaceSyntax, cancellationToken: cancellationToken) as INamedTypeSymbol;
+
+            return symbol;
+        }
+
+        private static void Execute(SourceProductionContext context, INamedTypeSymbol typeSymbol) {
+            var (source, className) = OutputGenerator.GenerateOutputs(typeSymbol);
+
+            context.AddSource($"{className}.generated.cs", SourceText.From(source, Encoding.UTF8, SourceHashAlgorithm.Sha256));
+        }
+
+        private IEnumerable<INamedTypeSymbol> GetThirdPartySemanticTargetsForGeneration(Compilation compilation, CancellationToken _) {
+            var wrapperSymbolWithoutNamespace = compilation.Assembly.GetTypeByMetadataName("WrapperList");
 
-            var wrapperSymbolWithoutNamespace = context.Compilation.Assembly.GetTypeByMetadataName("WrapperList");
             var wrapperListTypes =
-                (wrapperSymbolWithoutNamespace == null)
-                ? GetAllTypes(context.Compilation.Assembly.GlobalNamespace, x => x.Name == "WrapperList")
-                : new[] { wrapperSymbolWithoutNamespace };
-            var thirdPartyTypes =
+            (wrapperSymbolWithoutNamespace == null)
+            ? GetAllTypes(compilation.Assembly.GlobalNamespace, x => x.Name == "WrapperList")
+            : new[] { wrapperSymbolWithoutNamespace };
+
+            return
                 wrapperListTypes.SelectMany(x => x.GetMembers()
                 .Where(m => m.Name != ".ctor")
                 .Select(m => m as IFieldSymbol)
                 .Select(f => f.Type)
                 .Select(t => t as INamedTypeSymbol));
-
-            types = types.Concat(thirdPartyTypes);
-
-            var outputs = types.Select(OutputGenerator.GenerateOutputs);
-
-            foreach (var (source, className) in outputs) {
-                // Add the source code to the compilation
-                context.AddSource($"{className}.generated.cs", SourceText.From(source, Encoding.UTF8, SourceHashAlgorithm.Sha256));
-            }
         }
 
         /// <summary>
@@ -58,14 +77,5 @@ private IEnumerable<INamedTypeSymbol> GetAllTypes(INamespaceSymbol input, Func<I
                 }
             }
         }
-
-        /// <summary>
-        /// Gets all Types in the namespace decorated with the <see cref="DecorateAttribute"/> including nested namespaces.
-        /// </summary>
-        /// <param name="input"></param>
-        /// <returns></returns>
-        private IEnumerable<INamedTypeSymbol> GetAllDecoratedTypes(INamespaceSymbol input) {
-            return GetAllTypes(input, (x) => x.GetAttributes().Any(att => att.AttributeClass.Name == nameof(DecorateAttribute)));
-        }
     }
 }

README.md

@@ -40,7 +40,7 @@ public interface ICat
 }
 ```
 
-Build the project so the abstract class is generated for the interface. The generated class will be named after the interface, but without the `I` prefix. In this case, since the interface is `ICat` the class will be `CatDecorator`. Then create your decorator class as usual:
+Since this library is an [incremental source generator](https://github.com/dotnet/roslyn/blob/d8c21d64ca958840bdaa2898cb2324397dc57bbb/docs/features/incremental-generators.md), the abstract class should be generated after saving the changes to interface's file. The generated class will be named after the interface, but without the `I` prefix. In this case, since the interface is `ICat` the class will be `CatDecorator`. Then create your decorator class as usual:
 
 ```c#
 namespace SampleLibrary;