[pigeon] add support for multiple swift outputs

packages/pigeon/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 28.1.0
+
+* [swift] Adds support for multiple output locations in `swiftOut` and `--swift_out`.
+
 ## 28.0.0
 
 * **Breaking Change** Updates Kotlin and Swift generators to generate `suspend` functions and `async throws` signatures for `@FlutterApi` methods by default, and for `@HostApi` methods annotated with `@async`.

packages/pigeon/lib/src/generator_tools.dart

@@ -15,7 +15,7 @@ import 'generator.dart';
 /// The current version of pigeon.
 ///
 /// This must match the version in pubspec.yaml.
-const String pigeonVersion = '28.0.0';
+const String pigeonVersion = '28.1.0';
 
 /// Default plugin package name.
 const String defaultPluginPackageName = 'dev.flutter.pigeon';

packages/pigeon/lib/src/pigeon_lib.dart

@@ -294,8 +294,26 @@ class PigeonOptions {
   /// Options that control how Java will be generated.
   final JavaOptions? javaOptions;
 
-  /// Path to the swift file that will be generated.
-  final String? swiftOut;
+  /// Path to the swift file(s) that will be generated.
+  ///
+  /// Can be either a [String] for a single file, or an [Iterable<String>] for
+  /// multiple files.
+  final Object? swiftOut;
+
+  /// Returns all output paths for Swift from [swiftOut].
+  Iterable<String>? get swiftOutPaths {
+    final Object? out = swiftOut;
+    if (out == null) {
+      return null;
+    }
+    if (out is String) {
+      return <String>[out];
+    }
+    if (out is Iterable) {
+      return out.whereType<String>();
+    }
+    return null;
+  }
 
   /// Options that control how Swift will be generated.
   final SwiftOptions? swiftOptions;
@@ -361,7 +379,9 @@ class PigeonOptions {
       javaOptions: map.containsKey('javaOptions')
           ? JavaOptions.fromMap(map['javaOptions']! as Map<String, Object>)
           : null,
-      swiftOut: map['swiftOut'] as String?,
+      swiftOut: map['swiftOut'] is Iterable
+          ? (map['swiftOut']! as Iterable<dynamic>).cast<String>().toList()
+          : map['swiftOut'] as String?,
       swiftOptions: map.containsKey('swiftOptions')
           ? SwiftOptions.fromList(map['swiftOptions']! as Map<String, Object>)
           : null,
@@ -520,9 +540,9 @@ ${_argParser.usage}''';
       'java_use_generated_annotation',
       help: 'Adds the java.annotation.Generated annotation to the output.',
     )
-    ..addOption(
+    ..addMultiOption(
       'swift_out',
-      help: 'Path to generated Swift file (.swift).',
+      help: 'Path to generated Swift file(s) (.swift).',
       aliases: const <String>['experimental_swift_out'],
     )
     ..addOption(
@@ -596,6 +616,7 @@ ${_argParser.usage}''';
     // get set in the `run` function to accommodate users that are using the
     // `configurePigeon` function.
     final ArgResults results = _argParser.parse(args);
+    final swiftOuts = results['swift_out'] as List<String>;
 
     final opts = PigeonOptions(
       input: results['input'] as String?,
@@ -609,7 +630,9 @@ ${_argParser.usage}''';
         package: results['java_package'] as String?,
         useGeneratedAnnotation: results['java_use_generated_annotation'] as bool?,
       ),
-      swiftOut: results['swift_out'] as String?,
+      swiftOut: results.wasParsed('swift_out')
+          ? (swiftOuts.length == 1 ? swiftOuts.first : swiftOuts)
+          : null,
       kotlinOut: results['kotlin_out'] as String?,
       kotlinOptions: KotlinOptions(
         package: results['kotlin_package'] as String?,

packages/pigeon/lib/src/pigeon_lib_internal.dart

@@ -67,11 +67,11 @@ class InternalPigeonOptions {
               javaOut: options.javaOut!,
               copyrightHeader: copyrightHeader,
             ),
-      swiftOptions = options.swiftOut == null
+      swiftOptions = (options.swiftOutPaths == null || options.swiftOutPaths!.isEmpty)
           ? null
           : InternalSwiftOptions.fromSwiftOptions(
               options.swiftOptions ?? const SwiftOptions(),
-              swiftOut: options.swiftOut!,
+              swiftOuts: options.swiftOutPaths,
               copyrightHeader: copyrightHeader,
             ),
       kotlinOptions = options.kotlinOut == null
@@ -405,12 +405,39 @@ class SwiftGeneratorAdapter implements GeneratorAdapter {
       return;
     }
     const generator = SwiftGenerator();
-    generator.generate(options.swiftOptions!, root, sink, dartPackageName: options.dartPackageName);
+    final List<String> outputs = options.swiftOptions!.allSwiftOuts.toList();
+    if (outputs.isEmpty) {
+      generator.generate(
+        options.swiftOptions!,
+        root,
+        sink,
+        dartPackageName: options.dartPackageName,
+      );
+      return;
+    }
+    final buffer = StringBuffer();
+    generator.generate(
+      options.swiftOptions!,
+      root,
+      buffer,
+      dartPackageName: options.dartPackageName,
+    );
+    final content = buffer.toString();
+    sink.write(content);
+    for (final String outputPath in outputs.skip(1)) {
+      if (outputPath == 'stdout') {
+        stdout.write(content);
+      } else {
+        final file = File(path.posix.join(options.basePath ?? '', outputPath));
+        file.createSync(recursive: true);
+        file.writeAsStringSync(content);
+      }
+    }
   }
 
   @override
   IOSink? shouldGenerate(InternalPigeonOptions options, FileType _) =>
-      _openSink(options.swiftOptions?.swiftOut, basePath: options.basePath ?? '');
+      _openSink(options.swiftOptions?.allSwiftOuts.firstOrNull, basePath: options.basePath ?? '');
 
   @override
   List<Error> validate(InternalPigeonOptions options, Root root) {

packages/pigeon/lib/src/swift/swift_generator.dart

@@ -84,6 +84,7 @@ class InternalSwiftOptions extends InternalOptions {
   const InternalSwiftOptions({
     this.copyrightHeader,
     required this.swiftOut,
+    this.swiftOuts,
     this.fileSpecificClassNameComponent,
     this.errorClassName,
     this.includeErrorClass = true,
@@ -92,22 +93,38 @@ class InternalSwiftOptions extends InternalOptions {
   /// Creates InternalSwiftOptions from SwiftOptions.
   InternalSwiftOptions.fromSwiftOptions(
     SwiftOptions options, {
-    required this.swiftOut,
+    Iterable<String>? swiftOuts,
+    String? swiftOut,
     Iterable<String>? copyrightHeader,
   }) : copyrightHeader = options.copyrightHeader ?? copyrightHeader,
        fileSpecificClassNameComponent =
            options.fileSpecificClassNameComponent ??
-           swiftOut.split('/').lastOrNull?.split('.').firstOrNull ??
+           (swiftOuts?.firstOrNull ?? swiftOut ?? '')
+               .split('/')
+               .lastOrNull
+               ?.split('.')
+               .firstOrNull ??
            '',
        errorClassName = options.errorClassName,
-       includeErrorClass = options.includeErrorClass;
+       includeErrorClass = options.includeErrorClass,
+       swiftOut = swiftOut ?? swiftOuts?.firstOrNull ?? '',
+       swiftOuts = swiftOuts ?? (swiftOut != null ? <String>[swiftOut] : const <String>[]);
 
   /// A copyright header that will get prepended to generated code.
   final Iterable<String>? copyrightHeader;
 
   /// Path to the swift file that will be generated.
+  ///
+  /// If multiple output paths were specified, this contains the first path.
   final String swiftOut;
 
+  /// Paths to all swift files that will be generated.
+  final Iterable<String>? swiftOuts;
+
+  /// Returns all output paths for Swift.
+  Iterable<String> get allSwiftOuts =>
+      swiftOuts ?? (swiftOut.isNotEmpty ? <String>[swiftOut] : const <String>[]);
+
   /// A String to augment class names to avoid cross file collisions.
   final String? fileSpecificClassNameComponent;
 

packages/pigeon/pubspec.yaml

@@ -2,7 +2,7 @@ name: pigeon
 description: Code generator tool to make communication between Flutter and the host platform type-safe and easier.
 repository: https://github.com/flutter/packages/tree/main/packages/pigeon
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+pigeon%22
-version: 28.0.0 # This must match the version in lib/src/generator_tools.dart
+version: 28.1.0 # This must match the version in lib/src/generator_tools.dart
 
 environment:
   sdk: ^3.11.0

packages/pigeon/test/pigeon_lib_test.dart

@@ -5,6 +5,7 @@
 import 'dart:async';
 import 'dart:io';
 
+import 'package:path/path.dart' as path;
 import 'package:pigeon/src/ast.dart';
 import 'package:pigeon/src/generator_tools.dart';
 import 'package:pigeon/src/pigeon_lib.dart';
@@ -95,6 +96,21 @@ void main() {
     expect(opts.swiftOut, equals('Foo.swift'));
   });
 
+  test('parse args - multiple swift_out', () {
+    final PigeonOptions opts = Pigeon.parseArgs(<String>[
+      '--swift_out',
+      'Foo.swift',
+      '--swift_out',
+      'Bar.swift',
+    ]);
+    expect(opts.swiftOut, equals(<String>['Foo.swift', 'Bar.swift']));
+  });
+
+  test('parse args - comma-separated swift_out', () {
+    final PigeonOptions opts = Pigeon.parseArgs(<String>['--swift_out', 'Foo.swift,Bar.swift']);
+    expect(opts.swiftOut, equals(<String>['Foo.swift', 'Bar.swift']));
+  });
+
   test('parse args - kotlin_out', () {
     final PigeonOptions opts = Pigeon.parseArgs(<String>['--kotlin_out', 'Foo.kt']);
     expect(opts.kotlinOut, equals('Foo.kt'));
@@ -1406,6 +1422,115 @@ class Message {
     expect(options.cppOptions?.headerIncludePath, 'Header.path');
   });
 
+  test('@ConfigurePigeon swiftOut single', () {
+    const code = '''
+@ConfigurePigeon(PigeonOptions(
+  swiftOut: 'Foo.swift',
+))
+class Message {
+  int? id;
+}
+''';
+
+    final ParseResults results = parseSource(code);
+    final PigeonOptions options = PigeonOptions.fromMap(results.pigeonOptions!);
+    expect(options.swiftOut, 'Foo.swift');
+    expect(options.swiftOutPaths, <String>['Foo.swift']);
+  });
+
+  test('@ConfigurePigeon swiftOut multiple', () {
+    const code = '''
+@ConfigurePigeon(PigeonOptions(
+  swiftOut: <String>['Foo.swift', 'Bar.swift'],
+))
+class Message {
+  int? id;
+}
+''';
+
+    final ParseResults results = parseSource(code);
+    final PigeonOptions options = PigeonOptions.fromMap(results.pigeonOptions!);
+    expect(options.swiftOut, <String>['Foo.swift', 'Bar.swift']);
+    expect(options.swiftOutPaths, <String>['Foo.swift', 'Bar.swift']);
+  });
+
+  test('multiple swiftOut generation', () async {
+    final completer = Completer<void>();
+    const code = '''
+@HostApi()
+abstract class Api {
+  void doSomething();
+}
+''';
+    final Directory dir = Directory.systemTemp.createTempSync();
+    try {
+      final input = File(path.join(dir.path, 'input.dart'));
+      input.writeAsStringSync(code);
+      final String swift1 = path.join(dir.path, 'one.swift');
+      final String swift2 = path.join(dir.path, 'two.swift');
+      final int result = await Pigeon.runWithOptions(
+        PigeonOptions(
+          input: input.path,
+          swiftOut: <String>[swift1, swift2],
+          dartOut: path.join(dir.path, 'out.dart'),
+          dartPackageName: 'test_package',
+        ),
+      );
+      expect(result, equals(0));
+      expect(File(swift1).existsSync(), isTrue);
+      expect(File(swift2).existsSync(), isTrue);
+      final String content1 = File(swift1).readAsStringSync();
+      final String content2 = File(swift2).readAsStringSync();
+      expect(content1, isNotEmpty);
+      expect(content1, equals(content2));
+      expect(content1, contains('protocol Api'));
+      completer.complete();
+    } finally {
+      dir.deleteSync(recursive: true);
+    }
+    await completer.future;
+  });
+
+  test('multiple swift_out args generation', () async {
+    final completer = Completer<void>();
+    const code = '''
+@HostApi()
+abstract class Api {
+  void doSomething();
+}
+''';
+    final Directory dir = Directory.systemTemp.createTempSync();
+    try {
+      final input = File(path.join(dir.path, 'input.dart'));
+      input.writeAsStringSync(code);
+      final String swift1 = path.join(dir.path, 'one.swift');
+      final String swift2 = path.join(dir.path, 'two.swift');
+      final int result = await Pigeon.run(<String>[
+        '--input',
+        input.path,
+        '--dart_out',
+        path.join(dir.path, 'out.dart'),
+        '--package_name',
+        'test_package',
+        '--swift_out',
+        swift1,
+        '--swift_out',
+        swift2,
+      ]);
+      expect(result, equals(0));
+      expect(File(swift1).existsSync(), isTrue);
+      expect(File(swift2).existsSync(), isTrue);
+      final String content1 = File(swift1).readAsStringSync();
+      final String content2 = File(swift2).readAsStringSync();
+      expect(content1, isNotEmpty);
+      expect(content1, equals(content2));
+      completer.complete();
+    } finally {
+      dir.deleteSync(recursive: true);
+    }
+    await completer.future;
+  });
+
   test('return nullable', () {
     const code = '''
 @HostApi()

packages/pigeon/tool/shared/generation.dart

@@ -212,7 +212,7 @@ Future<int> runPigeon({
   bool kotlinIncludeErrorClass = true,
   bool kotlinUseGeneratedAnnotation = false,
   bool swiftIncludeErrorClass = true,
-  String? swiftOut,
+  Object? swiftOut,
   String? swiftErrorClassName,
   String? cppHeaderOut,
   String? cppSourceOut,