- Implement generating interface file.

Author: CodingFlow

AsyncTaskOrchestratorGenerator.UnitTests/IOrchestrator.cs

@@ -0,0 +1,9 @@
+// <auto-generated/>
+#nullable restore
+
+namespace TestLibrary;
+
+internal interface IOrchestrator
+{
+    public Task<int> Execute();
+}

AsyncTaskOrchestratorGenerator.UnitTests/Tests.cs

@@ -19,7 +19,8 @@ public void Setup() {
     [Test]
     public async Task OneInterface() {
         var source = await ReadCSharpFile<OrchestratorSpec>(true);
-        var generated = await ReadCSharpFile<Orchestrator>(false);
+        var generatedClass = await ReadCSharpFile<Orchestrator>(false);
+        var generatedInterface = await ReadCSharpFile<IOrchestrator>(false);
 
         await new VerifyCS.Test
         {
@@ -35,7 +36,8 @@ public async Task OneInterface() {
                 Sources = { source },
                 GeneratedSources =
                 {
-                    (typeof(Main), "Orchestrator.generated.cs", SourceText.From(generated, Encoding.UTF8, SourceHashAlgorithm.Sha256)),
+                    (typeof(Main), "Orchestrator.generated.cs", SourceText.From(generatedClass, Encoding.UTF8, SourceHashAlgorithm.Sha256)),
+                    (typeof(Main), "IOrchestrator.generated.cs", SourceText.From(generatedInterface, Encoding.UTF8, SourceHashAlgorithm.Sha256)),
                 },
             },
         }.RunAsync();

AsyncTaskOrchestratorGenerator/Main.cs

@@ -1,9 +1,6 @@
 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;
 
@@ -32,9 +29,11 @@ private static (INamedTypeSymbol, SemanticModel) GetSemanticTargetForGeneration(
         }
 
         private static void Execute(SourceProductionContext context, (INamedTypeSymbol typeSymbol, SemanticModel semanticModel) typeInfo) {
-            var (source, className) = OutputGenerator.GenerateOutputs(typeInfo);
+            var (classSource, className) = OutputGenerator.GenerateClassOutputs(typeInfo);
+            var (interfaceSource, interfaceName) = OutputGenerator.GenerateInterfaceOutputs(typeInfo.typeSymbol);
 
-            context.AddSource($"{className}.generated.cs", SourceText.From(source, Encoding.UTF8, SourceHashAlgorithm.Sha256));
+            context.AddSource($"{className}.generated.cs", SourceText.From(classSource, Encoding.UTF8, SourceHashAlgorithm.Sha256));
+            context.AddSource($"{interfaceName}.generated.cs", SourceText.From(interfaceSource, Encoding.UTF8, SourceHashAlgorithm.Sha256));
         }
     }
 }

AsyncTaskOrchestratorGenerator/OutputGenerator.cs

@@ -8,11 +8,10 @@ namespace AsyncTaskOrchestratorGenerator
 {
     internal static class OutputGenerator
     {
-        public static (string source, string className) GenerateOutputs((INamedTypeSymbol typeSymbol, SemanticModel semanticModel) typeInfo) {
+        public static (string source, string className) GenerateClassOutputs((INamedTypeSymbol typeSymbol, SemanticModel semanticModel) typeInfo) {
             var type = typeInfo.typeSymbol;
             var semanticModel = typeInfo.semanticModel;
-
-            var constructorArguments = type.GetAttributes().First((a) => a.AttributeClass.Name == nameof(AsyncTaskOrchestratorAttribute)).ConstructorArguments;
+            var constructorArguments = GetAttributeConstructorArguments(type);
             var className = constructorArguments.First().Value.ToString();
             var executeMethodName = constructorArguments.ElementAt(1).Value.ToString();
 
@@ -50,11 +49,37 @@ namespace {type.ContainingNamespace.ToDisplayString()};
             return (source, className);
         }
 
+        private static System.Collections.Immutable.ImmutableArray<TypedConstant> GetAttributeConstructorArguments(INamedTypeSymbol type) {
+            return type.GetAttributes().First((a) => a.AttributeClass.Name == nameof(AsyncTaskOrchestratorAttribute)).ConstructorArguments;
+        }
+
+        public static (string source, string interfaceName) GenerateInterfaceOutputs(INamedTypeSymbol type) {
+            var constructorArguments = GetAttributeConstructorArguments(type);
+            var className = constructorArguments.First().Value.ToString();
+            var executeMethodName = constructorArguments.ElementAt(1).Value.ToString();
+            var interfaceName = $"I{className}";
+            
+            var accessModifier = type.DeclaredAccessibility.ToString().ToLower();
+            var executeMethod = GetExecuteMethod(type);
+            var executeMethodAccessibility = executeMethod.DeclaredAccessibility.ToString().ToLower();
+            var formattedExecuteMethod = $"{executeMethodAccessibility} {executeMethod.ReturnType} {executeMethodName}();";
+
+            var source =
+$@"// <auto-generated/>
+#nullable restore
+
+namespace {type.ContainingNamespace.ToDisplayString()};
+
+{accessModifier} interface {interfaceName}
+{{
+    {formattedExecuteMethod}
+}}
+";
+            return (source, interfaceName);
+        }
+
         private static (ExecuteMethodSignatureData, Dictionary<string, TaskData>, TaskData) CreateExecuteMethodData(INamedTypeSymbol type, IEnumerable<IFieldSymbol> fields, string executeMethodName) {
-            var executeMethod = type
-                .GetMembers()
-                .Where(m => m is IMethodSymbol)
-                .First(m => (m as IMethodSymbol).MethodKind == MethodKind.Ordinary) as IMethodSymbol;
+            var executeMethod = GetExecuteMethod(type);
             var statements = (executeMethod.DeclaringSyntaxReferences.First().GetSyntax() as MethodDeclarationSyntax).Body.Statements;
             var variableStatements = statements.Remove(statements.Last());
 
@@ -110,6 +135,13 @@ private static (ExecuteMethodSignatureData, Dictionary<string, TaskData>, TaskDa
             }, variableData.ToDictionary(taskData => taskData.OutputName), finalTaskData);
         }
 
+        private static IMethodSymbol GetExecuteMethod(INamedTypeSymbol type) {
+            return type
+                            .GetMembers()
+                            .Where(m => m is IMethodSymbol)
+                            .First(m => (m as IMethodSymbol).MethodKind == MethodKind.Ordinary) as IMethodSymbol;
+        }
+
         private static string FormatExecuteMethod(ExecuteMethodSignatureData signatureData, Dictionary<string, TaskData> data, TaskData finalTaskData) {
             var formattedTaskDeclarations = data.Select(keyValue => {
                 var item = keyValue.Value;