[swift2objc] Filtering Support

pkgs/swift2objc/lib/src/config.dart

@@ -1,5 +1,7 @@
 import 'package:path/path.dart' as path;
 
+import 'ast/_core/interfaces/declaration.dart';
+
 const defaultTempDirPrefix = 'swift2objc_temp_';
 const symbolgraphFileSuffix = '.symbols.json';
 
@@ -32,11 +34,21 @@ class Config {
   /// intermediate files after generating the wrapper
   final Uri? tempDir;
 
+  /// Filter function to filter APIs 
+  /// 
+  /// APIs can be filtered by name
+  /// 
+  /// Includes all declarations by default
+  final bool Function(Declaration declaration)? include;
+
+  static bool _defaultInclude(_) => true;
+
   const Config({
     required this.input,
     required this.outputFile,
     this.tempDir,
     this.preamble,
+    this.include = Config._defaultInclude
   });
 }
 

pkgs/swift2objc/lib/src/generate_wrapper.dart

@@ -45,9 +45,10 @@ Future<void> generateWrapper(Config config) async {
     JsonFileInputConfig() => parseModuleName(symbolgraphJson),
   };
 
+
   final declarations = parseAst(symbolgraphJson);
-  final transformedDeclarations = transform(declarations);
-
+  final transformedDeclarations = transform(declarations, 
+    filter: config.include);
   final wrapperCode = generate(
     transformedDeclarations,
     moduleName: sourceModule,

pkgs/swift2objc/lib/src/transformer/transform.dart

@@ -13,20 +13,26 @@ import 'transformers/transform_globals.dart';
 
 typedef TransformationMap = Map<Declaration, Declaration>;
 
-List<Declaration> transform(List<Declaration> declarations) {
+/// Transforms the given declarations into the desired ObjC wrapped declarations
+List<Declaration> transform(List<Declaration> declarations, {
+  bool Function(Declaration)? filter
+}) {
   final TransformationMap transformationMap;
+  final _filter = filter ?? (declaration) => true;
+
+  final _declarations = declarations.where((d) => _filter(d));
 
   transformationMap = {};
 
   final globalNamer = UniqueNamer(
-    declarations.map((declaration) => declaration.name),
+    _declarations.map((declaration) => declaration.name),
   );
 
   final globals = Globals(
-    functions: declarations.whereType<GlobalFunctionDeclaration>().toList(),
-    variables: declarations.whereType<GlobalVariableDeclaration>().toList(),
+    functions: _declarations.whereType<GlobalFunctionDeclaration>().toList(),
+    variables: _declarations.whereType<GlobalVariableDeclaration>().toList(),
   );
-  final nonGlobals = declarations
+  final nonGlobals = _declarations
       .where(
         (declaration) =>
             declaration is! GlobalFunctionDeclaration &&

pkgs/swift2objc/test/unit/filter_test.dart

@@ -0,0 +1,110 @@
+// Copyright (c) 2024, the Dart project authors. 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.
+
+import 'dart:io';
+
+import 'package:path/path.dart' as path;
+import 'package:swift2objc/src/ast/declarations/compounds/class_declaration.dart';
+import 'package:swift2objc/swift2objc.dart';
+import 'package:test/test.dart';
+
+void main() {
+  group('Unit test for filter', () {
+    final thisDir = path.join(Directory.current.path, 'test/unit');
+
+    final file = path.join(thisDir, 'filter_test_input.swift');
+      test('A: Specific Files', () async {
+        final output = path.join(thisDir, 'filter_test_output_a.swift');
+        final actualOutputFile = path.join(thisDir, '${
+            path.basenameWithoutExtension(output)}.test${path.extension(output)
+        }');
+
+        await generateWrapper(Config(
+          input: FilesInputConfig(
+            files: [Uri.file(file)],
+          ),
+          outputFile: Uri.file(actualOutputFile),
+          tempDir: Directory(thisDir).uri,
+          preamble: '// Test preamble text',
+          include: (declaration) => declaration.name == 'Engine',
+        ));
+
+        final actualOutput = await File(actualOutputFile).readAsString();
+        final expectedOutput = File(output).readAsStringSync();
+
+        expect(actualOutput, expectedOutput);
+      });
+
+      test('B: Declarations of a specific type', () async {
+        final output = path.join(thisDir, 'filter_test_output_b.swift');
+        final actualOutputFile = path.join(thisDir, '${
+            path.basenameWithoutExtension(output)}.test${path.extension(output)
+        }');
+
+        await generateWrapper(Config(
+          input: FilesInputConfig(
+            files: [Uri.file(file)],
+          ),
+          outputFile: Uri.file(actualOutputFile),
+          tempDir: Directory(thisDir).uri,
+          preamble: '// Test preamble text',
+          include: (declaration) => declaration is ClassDeclaration,
+        ));
+
+        final actualOutput = await File(actualOutputFile).readAsString();
+        final expectedOutput = File(output).readAsStringSync();
+
+        expect(actualOutput, expectedOutput);
+      });
+
+      test('C: Nonexistent declaration', () async {
+        final output = path.join(thisDir, 'filter_test_output_c.swift');
+        final actualOutputFile = path.join(thisDir, '${
+            path.basenameWithoutExtension(output)}.test${path.extension(output)
+        }');
+
+        await generateWrapper(Config(
+          input: FilesInputConfig(
+            files: [Uri.file(file)],
+          ),
+          outputFile: Uri.file(actualOutputFile),
+          tempDir: Directory(thisDir).uri,
+          preamble: '// Test preamble text',
+          // The following declaration does not exist, 
+          // so none are produced in output
+          include: (declaration) => declaration.name == 'Ship',
+        ));
+
+        final actualOutput = await File(actualOutputFile).readAsString();
+        final expectedOutput = File(output).readAsStringSync();
+
+        expect(actualOutput, expectedOutput);
+      });
+
+    tearDown(() {
+      if (File(path.join(thisDir, 'symbolgraph_module.abi.json')).existsSync()) {
+        File(path.join(thisDir, 'symbolgraph_module.abi.json')).deleteSync();
+      }
+      if (File(path.join(thisDir, 'symbolgraph_module.swiftdoc')).existsSync()) {
+        File(path.join(thisDir, 'symbolgraph_module.swiftdoc')).deleteSync();
+      }
+      if (File(path.join(thisDir, 'symbolgraph_module.swiftmodule')).existsSync()) {
+        File(path.join(thisDir, 'symbolgraph_module.swiftmodule')).deleteSync();
+      }
+      if (File(path.join(thisDir, 'symbolgraph_module.swiftsource')).existsSync()) {
+        File(path.join(thisDir, 'symbolgraph_module.swiftsource')).deleteSync();
+      }
+      if (File(path.join(thisDir, 'symbolgraph_module.symbols.json')).existsSync()) {
+        File(path.join(thisDir, 'symbolgraph_module.symbols.json')).deleteSync();
+      }
+      if (File(path.join(thisDir, 'symbolgraph_module.swiftsourceinfo')).existsSync()) {
+        File(path.join(thisDir, 'symbolgraph_module.swiftsourceinfo')).deleteSync();
+      }
+
+      for (final file in Directory(thisDir).listSync().where((t) => path.extension(t.path, 2) == '.test.swift')) {
+        if (file is File) file.deleteSync();
+      }
+    });
+  });
+}

pkgs/swift2objc/test/unit/filter_test_input.swift

@@ -0,0 +1,135 @@
+import Foundation
+
+public struct Engine {
+    public let type: String
+    public let horsepower: Int
+
+    public init(type: String, horsepower: Int) {
+        self.type = type
+        self.horsepower = horsepower
+    }
+
+    public func displaySpecs() {
+        print("Engine: \(type), \(horsepower) HP")
+    }
+}
+
+
+public struct Tire {
+    public let brand: String
+    public let size: Int
+
+    public init(brand: String, size: Int) {
+        self.brand = brand
+        self.size = size
+    }
+
+    public func displayInfo() {
+        print("Tire: \(brand), size \(size)")
+    }
+}
+
+
+public struct Dimensions {
+    public let length: Double
+    public let width: Double
+    public let height: Double
+
+    public init(length: Double, width: Double, height: Double) {
+        self.length = length
+        self.width = width
+        self.height = height
+    }
+
+    public func displayDimensions() {
+        print("Dimensions (LxWxH): \(length) x \(width) x \(height) meters")
+    }
+}
+
+
+public class Vehicle {
+    public var make: String
+    public var model: String
+    public var engine: Engine
+    public var dimensions: Dimensions
+
+    public init(make: String, model: String, engine: Engine, dimensions: Dimensions) {
+        self.make = make
+        self.model = model
+        self.engine = engine
+        self.dimensions = dimensions
+    }
+
+    public func displayInfo() {
+        print("Vehicle: \(make) \(model)")
+        engine.displaySpecs()
+        dimensions.displayDimensions()
+    }
+}
+
+
+public class Car: Vehicle {
+    public var numberOfDoors: Int
+    public var tires: [Tire]
+
+    public init(make: String, model: String, engine: Engine, dimensions: Dimensions, numberOfDoors: Int, tires: [Tire]) {
+        self.numberOfDoors = numberOfDoors
+        self.tires = tires
+        super.init(make: make, model: model, engine: engine, dimensions: dimensions)
+    }
+
+    public func honk() {
+        print("Car \(make) \(model) goes 'Beep Beep!'")
+    }
+}
+
+
+public class ElectricCar: Car {
+    public var batteryCapacity: Int // in kWh
+
+    public init(make: String, model: String, dimensions: Dimensions, numberOfDoors: Int, tires: [Tire], batteryCapacity: Int) {
+        self.batteryCapacity = batteryCapacity
+        let electricEngine = Engine(type: "Electric", horsepower: batteryCapacity * 3) // Example calculation
+        super.init(make: make, model: model, engine: electricEngine, dimensions: dimensions, numberOfDoors: numberOfDoors, tires: tires)
+    }
+
+    public func chargeBattery() {
+        print("Charging \(make) \(model)... Battery capacity: \(batteryCapacity) kWh")
+    }
+}
+
+public class Bicycle {
+    public var brand: String
+    public var gearCount: Int
+    public var dimensions: Dimensions
+
+    public init(brand: String, gearCount: Int, dimensions: Dimensions) {
+        self.brand = brand
+        self.gearCount = gearCount
+        self.dimensions = dimensions
+    }
+
+    public func pedal() {
+        print("\(brand) bicycle is pedaling with \(gearCount) gears.")
+        dimensions.displayDimensions()
+    }
+}
+
+
+public class Garage {
+    private var vehicles: [Vehicle] = []
+
+    public init() {}
+
+    public func addVehicle(_ vehicle: Vehicle) {
+        vehicles.append(vehicle)
+        print("Added \(vehicle.make) \(vehicle.model) to the garage.")
+    }
+
+    public func listVehicles() {
+        print("Garage contains:")
+        for vehicle in vehicles {
+            print("- \(vehicle.make) \(vehicle.model)")
+        }
+    }
+}

pkgs/swift2objc/test/unit/filter_test_output_a.swift

@@ -0,0 +1,31 @@
+// Test preamble text
+
+import Foundation
+
+@objc public class EngineWrapper: NSObject {
+  var wrappedInstance: Engine
+
+  @objc public var horsepower: Int {
+    get {
+      wrappedInstance.horsepower
+    }
+  }
+
+  @objc public var type: String {
+    get {
+      wrappedInstance.type
+    }
+  }
+
+  init(_ wrappedInstance: Engine) {
+    self.wrappedInstance = wrappedInstance
+  }
+
+  @objc init(type: String, horsepower: Int) {
+    wrappedInstance = Engine(type: type, horsepower: horsepower)
+  }
+
+  @objc public func displaySpecs() {
+    wrappedInstance.displaySpecs()
+  }
+}