[swift2objc] Support Swift ARC features

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

@@ -38,21 +38,30 @@ class PropertyDeclaration extends AstNode
   PropertyStatements? getter;
   PropertyStatements? setter;
 
+  bool unowned;
+
+  bool weak;
+
+  bool lazy;
+
   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.unowned = false,
+      this.weak = false,
+      this.lazy = false})
+      : assert(!(isConstant && hasSetter)),
         assert(!(hasSetter && throws));
 
   @override

pkgs/swift2objc/lib/src/generator/generators/class_generator.dart

@@ -144,27 +144,47 @@ List<String> _generateClassProperty(PropertyDeclaration property) {
   if (property.isStatic) {
     header.write('static ');
   }
+  final prefixes = [
+    if (property.unowned) 'unowned',
+    if (property.weak) 'weak',
+  ];
 
-  header.write('public var ${property.name}: ${property.type.swiftType} {');
+  var prefix = prefixes.isEmpty ? '' : '${prefixes.join(' ')} ';
+  var propSwiftType = property.type.swiftType;
 
-  final getterLines = [
-    'get ${generateAnnotations(property)}{',
-    ...(property.getter?.statements.indent() ?? <String>[]),
-    '}'
-  ];
+  if (property.lazy) {
+    header
+        .write('public ${prefix}lazy var ${property.name}: $propSwiftType = {');
+    final getterLines = [
+      ...(property.getter?.statements.indent() ?? <String>[]),
+    ];
+    return [
+      header.toString(),
+      ...getterLines.indent(),
+      '}();\n',
+    ];
+  } else {
+    header.write('public ${prefix}var ${property.name}: $propSwiftType {');
 
-  final setterLines = [
-    'set {',
-    ...(property.setter?.statements.indent() ?? <String>[]),
-    '}'
-  ];
+    final getterLines = [
+      'get ${generateAnnotations(property)}{',
+      ...(property.getter?.statements.indent() ?? <String>[]),
+      '}'
+    ];
 
-  return [
-    header.toString(),
-    ...getterLines.indent(),
-    if (property.hasSetter) ...setterLines.indent(),
-    '}\n',
-  ];
+    final setterLines = [
+      'set {',
+      ...(property.setter?.statements.indent() ?? <String>[]),
+      '}'
+    ];
+
+    return [
+      header.toString(),
+      ...getterLines.indent(),
+      if (property.hasSetter) ...setterLines.indent(),
+      '}\n',
+    ];
+  }
 }
 
 List<String> _generateNestedDeclarations(ClassDeclaration declaration) => [

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

@@ -15,17 +15,22 @@ 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 : _parsePropertyHasSetter(propertySymbolJson),
     isStatic: isStatic,
-    throws: _parseVariableThrows(propertySymbolJson),
-    async: _parseVariableAsync(propertySymbolJson),
+    throws: info.throws,
+    async: info.async,
+    unowned: info.unowned,
+    weak: info.weak,
+    lazy: info.lazy,
   );
 }
 
@@ -36,14 +41,15 @@ GlobalVariableDeclaration parseGlobalVariableDeclaration(
 }) {
   final isConstant = _parseVariableIsConstant(variableSymbolJson);
   final hasSetter = _parsePropertyHasSetter(variableSymbolJson);
+  final variableModifiers = parsePropertyInfo(variableSymbolJson);
+
   return GlobalVariableDeclaration(
-    id: parseSymbolId(variableSymbolJson),
-    name: parseSymbolName(variableSymbolJson),
-    type: _parseVariableType(variableSymbolJson, symbolgraph),
-    isConstant: isConstant || !hasSetter,
-    throws: _parseVariableThrows(variableSymbolJson),
-    async: _parseVariableAsync(variableSymbolJson),
-  );
+      id: parseSymbolId(variableSymbolJson),
+      name: parseSymbolName(variableSymbolJson),
+      type: _parseVariableType(variableSymbolJson, symbolgraph),
+      isConstant: isConstant || !hasSetter,
+      throws: variableModifiers.throws,
+      async: variableModifiers.async);
 }
 
 ReferredType _parseVariableType(
@@ -53,9 +59,7 @@ 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') ||
@@ -69,16 +73,30 @@ bool _parseVariableIsConstant(Json variableSymbolJson) {
   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) {
+  final keywordIsPresent =
+      json.any((frag) => matchFragment(frag, 'keyword', keyword));
+  return keywordIsPresent;
 }
 
-bool _parseVariableAsync(Json json) {
-  final async = json['declarationFragments']
-      .any((frag) => matchFragment(frag, 'keyword', 'async'));
-  return async;
+typedef ParsedPropertyInfo = ({
+  bool async,
+  bool throws,
+  bool unowned,
+  bool weak,
+  bool lazy,
+  bool constant,
+});
+
+ParsedPropertyInfo parsePropertyInfo(Json json) {
+  return (
+    constant: _parseVariableIsConstant(json),
+    async: _findKeywordInFragments(json, 'async'),
+    throws: _findKeywordInFragments(json, 'throws'),
+    unowned: _findKeywordInFragments(json, 'unowned'),
+    weak: _findKeywordInFragments(json, 'weak'),
+    lazy: _findKeywordInFragments(json, 'lazy')
+  );
 }
 
 bool _parsePropertyHasSetter(Json propertySymbolJson) {

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

@@ -109,6 +109,13 @@ Declaration _transformVariable(
     isConstant: originalVariable.isConstant,
     throws: originalVariable.throws,
     async: originalVariable.async,
+    unowned: originalVariable is PropertyDeclaration
+        ? originalVariable.unowned
+        : false,
+    lazy:
+        originalVariable is PropertyDeclaration ? originalVariable.lazy : false,
+    weak:
+        originalVariable is PropertyDeclaration ? originalVariable.weak : false,
   );
 
   final getterStatements = _generateGetterStatements(

pkgs/swift2objc/test/integration/classes_and_properties_input.swift

@@ -29,17 +29,23 @@ public class MyClass {
 
     public let representableConstantProperty: Int
 
+    public weak var weakProperty: MyOtherClass?
+    public unowned var unownedProperty: MyOtherClass
+    public lazy var lazyProperty: Int = { 1 }();
+
 
     init(
         customVariableProperty: MyOtherClass, 
         customConstantProperty: MyOtherClass,
         representableVariableProperty: Int,
-        representableConstantProperty: Int
+        representableConstantProperty: Int,
+        unownedProperty: MyOtherClass
     ) {
         self.customVariableProperty = customVariableProperty
         self.customConstantProperty = customConstantProperty
         self.representableVariableProperty = representableVariableProperty
         self.representableConstantProperty = representableConstantProperty
+        self.unownedProperty = unownedProperty
     }
 }
 

pkgs/swift2objc/test/integration/classes_and_properties_output.swift

@@ -14,6 +14,28 @@ import Foundation
 @objc public class MyClassWrapper: NSObject {
   var wrappedInstance: MyClass
 
+  @objc public lazy var lazyProperty: Int = {
+      wrappedInstance.lazyProperty
+  }();
+
+  @objc public weak var weakProperty: MyOtherClassWrapper? {
+    get {
+      wrappedInstance.weakProperty == nil ? nil : MyOtherClassWrapper(wrappedInstance.weakProperty!)
+    }
+    set {
+      wrappedInstance.weakProperty = newValue?.wrappedInstance
+    }
+  }
+
+  @objc public unowned var unownedProperty: MyOtherClassWrapper {
+    get {
+      MyOtherClassWrapper(wrappedInstance.unownedProperty)
+    }
+    set {
+      wrappedInstance.unownedProperty = newValue.wrappedInstance
+    }
+  }
+
   @objc public var customGetterProperty: MyOtherClassWrapper {
     get {
       MyOtherClassWrapper(wrappedInstance.customGetterProperty)

pkgs/swift2objc/test/unit/parse_function_info_test.dart

@@ -18,7 +18,7 @@ void main() {
       decl.id: ParsedSymbol(json: Json(null), declaration: decl)
   };
   final emptySymbolgraph = ParsedSymbolgraph(parsedSymbols, {});
-  group('Valid json', () {
+  group('Function Valid json', () {
     void expectEqualParams(
       List<Parameter> actualParams,
       List<Parameter> expectedParams,