refactor(winrtgen): rename ArrayStyle enum to ArrayPassingStyle (#302)

packages/winrtgen/lib/src/models/array_passing_style.dart

@@ -0,0 +1,27 @@
+// Copyright (c) 2023, Dart | Windows. Please see the AUTHORS file for details.
+// All rights reserved. Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+/// Represents the various array-passing styles in WinRT.
+/// See https://learn.microsoft.com/uwp/winrt-cref/winrt-type-system#array-parameters
+enum ArrayPassingStyle {
+  /// Used when the caller provides an array for the method to fill, up to a
+  /// maximum array size.
+  ///
+  /// In this style, the array size parameter is an `in` parameter, while the
+  /// array parameter is an `out` parameter.
+  fill,
+
+  /// Used when the caller provides an array to the method.
+  ///
+  /// In this style, the array size parameter and the array parameter are both
+  /// `in` parameters.
+  pass,
+
+  /// Used when the caller receives an array that was allocated by the method.
+  ///
+  /// In this style, the array size parameter and the array parameter are both
+  /// `out` parameters. Additionally, the array parameter is passed by
+  /// reference (that is, `ArrayType**`, rather than `ArrayType*`).
+  receive
+}

packages/winrtgen/lib/src/models/models.dart

@@ -2,7 +2,7 @@
 // All rights reserved. Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-export 'array_style.dart';
+export 'array_passing_style.dart';
 export 'generic_type.dart';
 export 'json.dart';
 export 'projection_kind.dart';

packages/winrtgen/lib/src/projections/parameter.dart

@@ -161,9 +161,11 @@ base class ParameterProjection {
     // projected as List. See the ArrayParameterProjection class.
     if (parameter.isSimpleArraySizeParam) {
       final identifier = parameter.toArrayParamName();
-      return switch (parameter.arrayStyle) {
-        ArrayStyle.fill || ArrayStyle.receive => '${identifier}Size',
-        ArrayStyle.pass => '$identifier.length',
+      return switch (parameter.arrayPassingStyle) {
+        ArrayPassingStyle.fill ||
+        ArrayPassingStyle.receive =>
+          '${identifier}Size',
+        ArrayPassingStyle.pass => '$identifier.length',
       };
     }
 

packages/winrtgen/lib/src/projections/types/array.dart

@@ -15,16 +15,18 @@ abstract base class ArrayParameterProjection extends ParameterProjection {
 
   /// Returns the appropriate projection for the parameter.
   factory ArrayParameterProjection.create(Parameter param) {
-    final Parameter(:arrayStyle, :parent, :projectionKind) = param;
+    final Parameter(:arrayPassingStyle, :parent, :projectionKind) = param;
     try {
-      return switch (arrayStyle) {
-        ArrayStyle.fill => FillArrayParameterProjection(param),
-        ArrayStyle.pass when projectionKind == ProjectionKind.stringArray =>
+      return switch (arrayPassingStyle) {
+        ArrayPassingStyle.fill => FillArrayParameterProjection(param),
+        ArrayPassingStyle.pass
+            when projectionKind == ProjectionKind.stringArray =>
           StringPassArrayParameterProjection(param),
-        ArrayStyle.pass when projectionKind == ProjectionKind.structArray =>
+        ArrayPassingStyle.pass
+            when projectionKind == ProjectionKind.structArray =>
           StructPassArrayParameterProjection(param),
-        ArrayStyle.pass => PassArrayParameterProjection(param),
-        ArrayStyle.receive => ReceiveArrayParameterProjection(param),
+        ArrayPassingStyle.pass => PassArrayParameterProjection(param),
+        ArrayPassingStyle.receive => ReceiveArrayParameterProjection(param),
       };
     } catch (_) {
       print("Failed to project parameter '$param' from '$parent'.");

packages/winrtgen/lib/src/utilities/extensions/parameter_helpers.dart

@@ -4,6 +4,7 @@
 
 import 'package:winmd/winmd.dart';
 
+import '../../exception/exception.dart';
 import '../../models/models.dart';
 import '../../projections/type.dart';
 import 'type_identifier_helpers.dart';
@@ -15,7 +16,7 @@ extension ParameterHelpers on Parameter {
         ..attributes = attributes
         ..name = name;
 
-  ArrayStyle get arrayStyle {
+  ArrayPassingStyle get arrayPassingStyle {
     assert(isReferenceType || isSimpleArraySizeParam || isSimpleArrayType);
 
     var arrayParam = this;
@@ -33,12 +34,20 @@ extension ParameterHelpers on Parameter {
           .firstOrNull;
     }
 
-    if (arraySizeParam == null) return ArrayStyle.receive;
-    if (arraySizeParam.isInParam) {
-      if (arrayParam.isOutParam) return ArrayStyle.fill;
-      return ArrayStyle.pass;
+    if (arraySizeParam == null || arrayParam.isReferenceType) {
+      return ArrayPassingStyle.receive;
     }
-    return ArrayStyle.receive;
+
+    if (arraySizeParam.isInParam && arrayParam.isOutParam) {
+      return ArrayPassingStyle.fill;
+    }
+
+    if (arraySizeParam.isInParam && arrayParam.isInParam) {
+      return ArrayPassingStyle.pass;
+    }
+
+    throw WinRTGenException(
+        'Failed to determine array-passing style for parameter $name');
   }
 
   bool get isClassVariableType => typeIdentifier.isClassVariableType;