[swift2objc] Property Parsing and Generation Refactoring (#2056)

Author: nikeokoronkwo

pkgs/swift2objc/lib/src/ast/declarations/compounds/members/property_declaration.dart

@@ -33,26 +33,29 @@ class PropertyDeclaration extends AstNode
   @override
   bool async;
 
+  bool mutating;
+
   bool hasSetter;
 
   PropertyStatements? getter;
   PropertyStatements? setter;
 
   bool isStatic;
 
-  PropertyDeclaration({
-    required this.id,
-    required this.name,
-    required this.type,
-    this.hasSetter = false,
-    this.isConstant = false,
-    this.hasObjCAnnotation = false,
-    this.getter,
-    this.setter,
-    this.isStatic = false,
-    this.throws = false,
-    this.async = false,
-  })  : assert(!(isConstant && hasSetter)),
+  PropertyDeclaration(
+      {required this.id,
+      required this.name,
+      required this.type,
+      this.hasSetter = false,
+      this.isConstant = false,
+      this.hasObjCAnnotation = false,
+      this.getter,
+      this.setter,
+      this.isStatic = false,
+      this.throws = false,
+      this.async = false,
+      this.mutating = false})
+      : assert(!(isConstant && hasSetter)),
         assert(!(hasSetter && throws));
 
   @override

pkgs/swift2objc/lib/src/parser/parsers/declaration_parsers/parse_variable_declaration.dart

@@ -15,17 +15,17 @@ PropertyDeclaration parsePropertyDeclaration(
   ParsedSymbolgraph symbolgraph, {
   bool isStatic = false,
 }) {
-  final isConstant = _parseVariableIsConstant(propertySymbolJson);
+  final info = parsePropertyInfo(propertySymbolJson['declarationFragments']);
   return PropertyDeclaration(
     id: parseSymbolId(propertySymbolJson),
     name: parseSymbolName(propertySymbolJson),
     type: _parseVariableType(propertySymbolJson, symbolgraph),
     hasObjCAnnotation: parseSymbolHasObjcAnnotation(propertySymbolJson),
-    isConstant: isConstant,
-    hasSetter: isConstant ? false : _parsePropertyHasSetter(propertySymbolJson),
+    isConstant: info.constant,
+    hasSetter: info.constant ? false : info.setter,
     isStatic: isStatic,
-    throws: _parseVariableThrows(propertySymbolJson),
-    async: _parseVariableAsync(propertySymbolJson),
+    throws: info.throws,
+    async: info.async,
   );
 }
 
@@ -34,15 +34,14 @@ GlobalVariableDeclaration parseGlobalVariableDeclaration(
   ParsedSymbolgraph symbolgraph, {
   bool isStatic = false,
 }) {
-  final isConstant = _parseVariableIsConstant(variableSymbolJson);
-  final hasSetter = _parsePropertyHasSetter(variableSymbolJson);
+  final info = parsePropertyInfo(variableSymbolJson['declarationFragments']);
   return GlobalVariableDeclaration(
     id: parseSymbolId(variableSymbolJson),
     name: parseSymbolName(variableSymbolJson),
     type: _parseVariableType(variableSymbolJson, symbolgraph),
-    isConstant: isConstant || !hasSetter,
-    throws: _parseVariableThrows(variableSymbolJson),
-    async: _parseVariableAsync(variableSymbolJson),
+    isConstant: info.constant || !info.setter,
+    throws: info.throws,
+    async: info.async,
   );
 }
 
@@ -53,9 +52,7 @@ ReferredType _parseVariableType(
     parseTypeAfterSeparator(
         TokenList(propertySymbolJson['names']['subHeading']), symbolgraph);
 
-bool _parseVariableIsConstant(Json variableSymbolJson) {
-  final fragmentsJson = variableSymbolJson['declarationFragments'];
-
+bool _parseVariableIsConstant(Json fragmentsJson) {
   final declarationKeyword = fragmentsJson.firstWhere(
     (json) =>
         matchFragment(json, 'keyword', 'var') ||
@@ -65,24 +62,39 @@ bool _parseVariableIsConstant(Json variableSymbolJson) {
       'Expected to find "var" or "let" as a keyword, found none',
     ),
   );
-
   return matchFragment(declarationKeyword, 'keyword', 'let');
 }
 
-bool _parseVariableThrows(Json json) {
-  final throws = json['declarationFragments']
-      .any((frag) => matchFragment(frag, 'keyword', 'throws'));
-  return throws;
+bool _findKeywordInFragments(Json json, String keyword) {
+  return json.any((frag) => matchFragment(frag, 'keyword', keyword));
 }
 
-bool _parseVariableAsync(Json json) {
-  final async = json['declarationFragments']
-      .any((frag) => matchFragment(frag, 'keyword', 'async'));
-  return async;
+typedef ParsedPropertyInfo = ({
+  bool async,
+  bool throws,
+  bool constant,
+  bool getter,
+  bool setter,
+  bool mutating,
+});
+
+ParsedPropertyInfo parsePropertyInfo(Json json) {
+  final (getter, setter) = _parsePropertyGetAndSet(json);
+  return (
+    constant: _parseVariableIsConstant(json),
+    async: _findKeywordInFragments(json, 'async'),
+    throws: _findKeywordInFragments(json, 'throws'),
+    getter: getter,
+    setter: setter,
+    mutating: _findKeywordInFragments(json, 'mutating')
+  );
 }
 
-bool _parsePropertyHasSetter(Json propertySymbolJson) {
-  final fragmentsJson = propertySymbolJson['declarationFragments'];
+(bool, bool) _parsePropertyGetAndSet(Json fragmentsJson, {String? path}) {
+  if (fragmentsJson.any((frag) => matchFragment(frag, 'text', ' { get }'))) {
+    // has explicit getter and no explicit setter
+    return (true, false);
+  }
 
   final hasExplicitSetter =
       fragmentsJson.any((frag) => matchFragment(frag, 'keyword', 'set'));
@@ -92,21 +104,21 @@ bool _parsePropertyHasSetter(Json propertySymbolJson) {
   if (hasExplicitGetter) {
     if (hasExplicitSetter) {
       // has explicit getter and has explicit setter
-      return true;
+      return (true, true);
     } else {
       // has explicit getter and no explicit setter
-      return false;
+      return (true, false);
     }
   } else {
     if (hasExplicitSetter) {
       // has no explicit getter and but has explicit setter
       throw Exception(
-        'Invalid property at ${propertySymbolJson.path}. '
+        'Invalid property${path != null ? ' at $path' : ''}. '
         'Properties can not have a setter without a getter',
       );
     } else {
-      // has no explicit getter and no explicit setter
-      return true;
+      // has implicit getter and implicit setter
+      return (true, true);
     }
   }
 }

pkgs/swift2objc/lib/src/transformer/transformers/transform_variable.dart

@@ -33,6 +33,7 @@ Declaration? transformProperty(
     originalProperty,
     globalNamer,
     transformationMap,
+    property: true,
     wrapperPropertyName: originalProperty.name,
     variableReferenceExpression: '$propertySource.${originalProperty.name}',
   );
@@ -60,6 +61,7 @@ Declaration _transformVariable(
   VariableDeclaration originalVariable,
   UniqueNamer globalNamer,
   TransformationMap transformationMap, {
+  bool property = false,
   required String wrapperPropertyName,
   required String variableReferenceExpression,
 }) {

pkgs/swift2objc/test/integration/structs_and_properties_input.swift

@@ -29,6 +29,10 @@ public struct MyStruct {
 
     public let representableConstantProperty: Int
 
+    public var mutatingProperty: Int {
+        mutating get { 1 }
+    }
+
 
     init(
         customVariableProperty: MyOtherStruct, 

pkgs/swift2objc/test/integration/structs_and_properties_output.swift

@@ -14,6 +14,12 @@ import Foundation
 @objc public class MyStructWrapper: NSObject {
   var wrappedInstance: MyStruct
 
+  @objc public var mutatingProperty: Int {
+    get {
+      wrappedInstance.mutatingProperty
+    }
+  }
+
   @objc public var customGetterProperty: MyOtherStructWrapper {
     get {
       MyOtherStructWrapper(wrappedInstance.customGetterProperty)