[Rgen] Add factory method that will create an aux variable for string…

…s. (#22080)

Co-authored-by: GitHub Actions Autoformatter <[email protected]>

src/rgen/Microsoft.Macios.Generator/DataModel/Parameter.Generator.cs

@@ -6,10 +6,13 @@ namespace Microsoft.Macios.Generator.DataModel;
 readonly partial struct Parameter {
 
 	public enum VariableType {
+		BlockLiteral,
 		Handle,
 		NSArray,
-		BlockLiteral,
+		NSString,
+		NSStringStruct,
 		PrimitivePointer,
+		StringPointer,
 	}
 
 	/// <summary>
@@ -19,11 +22,17 @@ public enum VariableType {
 	/// <param name="variableType">The type of aux variable.</param>
 	/// <returns>The name of the aux variable to use.</returns>
 	public string? GetNameForVariableType (VariableType variableType)
-		=> variableType switch {
-			VariableType.Handle => $"{Name}__handle__",
-			VariableType.NSArray => $"nsa_{Name}",
-			VariableType.BlockLiteral => $"block_ptr_{Name}",
-			VariableType.PrimitivePointer => $"converted_{Name}",
+	{
+		var cleanedName = Name.Replace ("@", "");
+		return variableType switch {
+			VariableType.BlockLiteral => $"block_ptr_{cleanedName}",
+			VariableType.Handle => $"{cleanedName}__handle__",
+			VariableType.NSArray => $"nsa_{cleanedName}",
+			VariableType.NSString => $"ns{cleanedName}",
+			VariableType.NSStringStruct => $"_s{cleanedName}",
+			VariableType.PrimitivePointer => $"converted_{cleanedName}",
+			VariableType.StringPointer => $"_p{cleanedName}",
 			_ => null
 		};
+	}
 }

src/rgen/Microsoft.Macios.Generator/Emitters/BindingSyntaxFactory.ObjCRuntime.cs

@@ -42,9 +42,9 @@ static partial class BindingSyntaxFactory {
 		var enumBackingValue = parameter.Type.EnumUnderlyingType.Value.GetKeyword ();
 		var castExpression = CastExpression (IdentifierName (marshalType), // (IntPtr/UIntPtr) cast
 			CastExpression (
-				IdentifierName (enumBackingValue),
-				IdentifierName (parameter.Name)
-					.WithLeadingTrivia (Space))
+					IdentifierName (enumBackingValue),
+					IdentifierName (parameter.Name)
+						.WithLeadingTrivia (Space))
 				.WithLeadingTrivia (Space)); // (backingfield) (variable) cast
 		return castExpression;
 	}
@@ -89,14 +89,15 @@ static partial class BindingSyntaxFactory {
 			return null;
 		// (byte) 1
 		var castOne = CastExpression (
-				PredefinedType (Token (SyntaxKind.ByteKeyword)),
-				LiteralExpression (SyntaxKind.NumericLiteralExpression, Literal (1)).WithLeadingTrivia (Space).WithTrailingTrivia (Space)
-				);
+			PredefinedType (Token (SyntaxKind.ByteKeyword)),
+			LiteralExpression (SyntaxKind.NumericLiteralExpression, Literal (1)).WithLeadingTrivia (Space)
+				.WithTrailingTrivia (Space)
+		);
 		// (byte) 0
 		var castZero = CastExpression (
-				PredefinedType (Token (SyntaxKind.ByteKeyword)),
-				LiteralExpression (SyntaxKind.NumericLiteralExpression, Literal (0)).WithLeadingTrivia (Space)
-				).WithLeadingTrivia (Space);
+			PredefinedType (Token (SyntaxKind.ByteKeyword)),
+			LiteralExpression (SyntaxKind.NumericLiteralExpression, Literal (0)).WithLeadingTrivia (Space)
+		).WithLeadingTrivia (Space);
 
 		// with this exact space count
 		// foo ? (byte) 1 : (byte) 0
@@ -210,7 +211,8 @@ static partial class BindingSyntaxFactory {
 
 		// generates: variable = {FactoryCall}
 		var declarator = VariableDeclarator (Identifier (variableName))
-			.WithInitializer (EqualsValueClause (factoryInvocation.WithLeadingTrivia (Space)).WithLeadingTrivia (Space));
+			.WithInitializer (EqualsValueClause (factoryInvocation.WithLeadingTrivia (Space))
+				.WithLeadingTrivia (Space));
 		// generates the final statement: 
 		// var x = zone.GetHandle ();
 		// or 
@@ -228,6 +230,38 @@ static partial class BindingSyntaxFactory {
 			));
 	}
 
+	internal static LocalDeclarationStatementSyntax? GetStringAuxVariable (in Parameter parameter)
+	{
+		if (parameter.Type.Name != "string")
+			return null;
+
+		var variableName = parameter.GetNameForVariableType (Parameter.VariableType.NSString);
+		if (variableName is null)
+			return null;
+
+		// generates: CFString.CreateNative ({parameter.Name});
+		var cfstringFactoryInvocation = InvocationExpression (
+				MemberAccessExpression (
+					SyntaxKind.SimpleMemberAccessExpression,
+					IdentifierName ("CFString"),
+					IdentifierName ("CreateNative").WithTrailingTrivia (Space))
+			)
+			.WithArgumentList (ArgumentList (SingletonSeparatedList (
+				Argument (IdentifierName (parameter.Name)))));
+
+		// generates {var} = CFString.CreateNative ({parameter.Name});
+		var declarator = VariableDeclarator (Identifier (variableName).WithLeadingTrivia (Space).WithTrailingTrivia (Space))
+			.WithInitializer (EqualsValueClause (cfstringFactoryInvocation.WithLeadingTrivia (Space)));
+
+
+		// put everythign together
+		var declaration = VariableDeclaration (IdentifierName (Identifier (
+				TriviaList (), SyntaxKind.VarKeyword, "var", "var", TriviaList ())))
+			.WithVariables (SingletonSeparatedList (declarator));
+
+		return LocalDeclarationStatement (declaration);
+	}
+
 	static string? GetObjCMessageSendMethodName<T> (ExportData<T> exportData,
 		TypeInfo returnType, ImmutableArray<Parameter> parameters, bool isSuper = false, bool isStret = false)
 		where T : Enum

tests/rgen/Microsoft.Macios.Generator.Tests/DataModel/ParameterTests.cs

@@ -19,6 +19,8 @@ public IEnumerator<object []> GetEnumerator ()
 			yield return [exampleParameter, Parameter.VariableType.BlockLiteral, $"block_ptr_{exampleParameter.Name}"];
 			yield return [exampleParameter, Parameter.VariableType.PrimitivePointer, $"converted_{exampleParameter.Name}"];
 			yield return [exampleParameter, Parameter.VariableType.NSArray, $"nsa_{exampleParameter.Name}"];
+			yield return [exampleParameter, Parameter.VariableType.NSString, $"ns{exampleParameter.Name}"];
+			yield return [exampleParameter, Parameter.VariableType.NSStringStruct, $"_s{exampleParameter.Name}"];
 		}
 
 		IEnumerator IEnumerable.GetEnumerator () => GetEnumerator ();

tests/rgen/Microsoft.Macios.Generator.Tests/Emitters/BindingSyntaxFactoryObjCRuntimeTests.cs

@@ -195,7 +195,7 @@ void GetNSArrayAuxVariableTests (in Parameter parameter, string? expectedDeclara
 		}
 	}
 
-	class TestDataCodeChangesFromClassDeclaration : IEnumerable<object []> {
+	class TestDataGetHandleAuxVariableTests : IEnumerable<object []> {
 		public IEnumerator<object []> GetEnumerator ()
 		{
 			// nsobject type
@@ -236,7 +236,7 @@ public IEnumerator<object []> GetEnumerator ()
 	}
 
 	[Theory]
-	[ClassData (typeof (TestDataCodeChangesFromClassDeclaration))]
+	[ClassData (typeof (TestDataGetHandleAuxVariableTests))]
 	void GetHandleAuxVariableTests (in Parameter parameter, string? expectedDeclaration, bool withNullAllowed)
 	{
 		var declaration = GetHandleAuxVariable (parameter, withNullAllowed: withNullAllowed);
@@ -247,4 +247,34 @@ void GetHandleAuxVariableTests (in Parameter parameter, string? expectedDeclarat
 			Assert.Equal (expectedDeclaration, declaration.ToString ());
 		}
 	}
+
+	class TestDataGetStringAuxVariableTest : IEnumerable<object []> {
+		public IEnumerator<object []> GetEnumerator ()
+		{
+			yield return [
+				new Parameter (0, ReturnTypeForString (), "myParam"),
+				"var nsmyParam = CFString.CreateNative (myParam);",
+			];
+
+			yield return [
+				new Parameter (0, ReturnTypeForBool (), "myParam"),
+				null!,
+			];
+		}
+
+		IEnumerator IEnumerable.GetEnumerator () => GetEnumerator ();
+	}
+
+	[Theory]
+	[ClassData (typeof (TestDataGetStringAuxVariableTest))]
+	void GetStringAuxVariableTests (in Parameter parameter, string? expectedDeclaration)
+	{
+		var declaration = GetStringAuxVariable (parameter);
+		if (expectedDeclaration is null) {
+			Assert.Null (declaration);
+		} else {
+			Assert.NotNull (declaration);
+			Assert.Equal (expectedDeclaration, declaration.ToString ());
+		}
+	}
 }