ffi just getting started

packages/pigeon/lib/src/dart/dart_generator.dart

@@ -47,6 +47,7 @@ class DartOptions {
     this.sourceOutPath,
     this.testOutPath,
     this.useJni = false,
+    this.useFfi = false,
     this.dartOut,
   });
 
@@ -62,6 +63,9 @@ class DartOptions {
   /// Whether to use Jni for generating kotlin interop code.
   final bool useJni;
 
+  /// Whether to use Ffi for generating swift interop code.
+  final bool useFfi;
+
   /// Path to output generated Dart file.
   final String? dartOut;
 
@@ -75,6 +79,7 @@ class DartOptions {
       sourceOutPath: map['sourceOutPath'] as String?,
       testOutPath: map['testOutPath'] as String?,
       useJni: map['useJni'] as bool? ?? false,
+      useFfi: map['useFfi'] as bool? ?? false,
       dartOut: map['dartOut'] as String?,
     );
   }
@@ -87,6 +92,7 @@ class DartOptions {
       if (sourceOutPath != null) 'sourceOutPath': sourceOutPath!,
       if (testOutPath != null) 'testOutPath': testOutPath!,
       if (useJni) 'useJni': useJni,
+      if (useFfi) 'useFfi': useFfi,
       if (dartOut != null) 'dartOut': dartOut!,
     };
     return result;

packages/pigeon/lib/src/kotlin/kotlin_generator.dart

@@ -42,7 +42,7 @@ class KotlinOptions {
     this.package,
     this.copyrightHeader,
     this.useJni = false,
-    this.exampleAppDirectory,
+    this.appDirectory,
     this.errorClassName,
     this.includeErrorClass = true,
     this.fileSpecificClassNameComponent,
@@ -57,8 +57,8 @@ class KotlinOptions {
   /// Whether to use Jni when possible.
   final bool useJni;
 
-  /// The directory that the example app exists in, this is required for Jni APIs.
-  final String? exampleAppDirectory;
+  /// The directory that the app exists in, this is required for Jni APIs.
+  final String? appDirectory;
 
   /// The name of the error class used for passing custom error parameters.
   final String? errorClassName;
@@ -78,7 +78,7 @@ class KotlinOptions {
     return KotlinOptions(
       package: map['package'] as String?,
       useJni: map['useJni'] as bool? ?? false,
-      exampleAppDirectory: map['exampleAppDirectory'] as String?,
+      appDirectory: map['appDirectory'] as String?,
       copyrightHeader: map['copyrightHeader'] as Iterable<String>?,
       errorClassName: map['errorClassName'] as String?,
       includeErrorClass: map['includeErrorClass'] as bool? ?? true,
@@ -93,8 +93,7 @@ class KotlinOptions {
     final Map<String, Object> result = <String, Object>{
       if (package != null) 'package': package!,
       if (useJni) 'useJni': useJni,
-      if (exampleAppDirectory != null)
-        'exampleAppDirectory': exampleAppDirectory!,
+      if (appDirectory != null) 'appDirectory': appDirectory!,
       if (copyrightHeader != null) 'copyrightHeader': copyrightHeader!,
       if (errorClassName != null) 'errorClassName': errorClassName!,
       'includeErrorClass': includeErrorClass,
@@ -111,7 +110,7 @@ class KotlinOptions {
   }
 }
 
-///
+/// Options that control how Kotlin code will be generated.
 class InternalKotlinOptions extends InternalOptions {
   /// Creates a [InternalKotlinOptions] object
   const InternalKotlinOptions({
@@ -121,7 +120,7 @@ class InternalKotlinOptions extends InternalOptions {
     this.errorClassName,
     this.includeErrorClass = true,
     this.useJni = false,
-    this.exampleAppDirectory,
+    this.appDirectory,
     this.fileSpecificClassNameComponent,
   });
 
@@ -135,7 +134,7 @@ class InternalKotlinOptions extends InternalOptions {
         errorClassName = options.errorClassName,
         includeErrorClass = options.includeErrorClass,
         useJni = options.useJni,
-        exampleAppDirectory = options.exampleAppDirectory,
+        appDirectory = options.appDirectory,
         fileSpecificClassNameComponent =
             options.fileSpecificClassNameComponent ??
                 kotlinOut.split('/').lastOrNull?.split('.').first;
@@ -161,8 +160,8 @@ class InternalKotlinOptions extends InternalOptions {
   /// Whether to use Jni for generating kotlin interop code.
   final bool useJni;
 
-  /// The directory that the example app exists in, this is required for Jni APIs.
-  final String? exampleAppDirectory;
+  /// The directory that the app exists in, this is required for Jni APIs.
+  final String? appDirectory;
 
   /// A String to augment class names to avoid cross file collisions.
   final String? fileSpecificClassNameComponent;

packages/pigeon/lib/src/pigeon_lib.dart

@@ -657,6 +657,7 @@ ${_argParser.usage}''';
           DartGeneratorAdapter(),
           JavaGeneratorAdapter(),
           SwiftGeneratorAdapter(),
+          FfigenConfigGeneratorAdapter(),
           KotlinGeneratorAdapter(),
           JnigenYamlGeneratorAdapter(),
           CppGeneratorAdapter(),

packages/pigeon/lib/src/pigeon_lib_internal.dart

@@ -25,6 +25,7 @@ import 'kotlin/jnigen_yaml_generator.dart';
 import 'kotlin/kotlin_generator.dart';
 import 'objc/objc_generator.dart';
 import 'pigeon_lib.dart';
+import 'swift/ffigen_config_generator.dart';
 import 'swift/swift_generator.dart';
 
 /// Options used when running the code generator.
@@ -476,6 +477,52 @@ class SwiftGeneratorAdapter implements GeneratorAdapter {
   List<Error> validate(InternalPigeonOptions options, Root root) => <Error>[];
 }
 
+/// A [GeneratorAdapter] that generates FfigenConfig source code.
+class FfigenConfigGeneratorAdapter implements GeneratorAdapter {
+  /// Constructor for [FfigenConfigGeneratorAdapter].
+  FfigenConfigGeneratorAdapter(
+      {this.fileTypeList = const <FileType>[FileType.na]});
+
+  @override
+  List<FileType> fileTypeList;
+
+  @override
+  void generate(StringSink sink, InternalPigeonOptions options, Root root,
+      FileType fileType) {
+    if (options.swiftOptions == null || options.dartOptions == null) {
+      return;
+    }
+    final FfigenConfigGenerator generator = FfigenConfigGenerator();
+
+    final InternalFfigenConfigOptions ffigenYamlOptions =
+        InternalFfigenConfigOptions(
+      options.dartOptions!,
+      options.swiftOptions!,
+      options.basePath,
+      options.dartOptions?.dartOut,
+      options.swiftOptions!.swiftOut,
+    );
+
+    generator.generate(
+      ffigenYamlOptions,
+      root,
+      sink,
+      dartPackageName: options.dartPackageName,
+    );
+  }
+
+  @override
+  IOSink? shouldGenerate(InternalPigeonOptions options, FileType _) =>
+      options.swiftOptions?.appDirectory != null &&
+              (options.swiftOptions?.useFfi ?? false)
+          ? _openSink('ffigen_config.dart',
+              basePath: options.swiftOptions?.appDirectory ?? '')
+          : null;
+
+  @override
+  List<Error> validate(InternalPigeonOptions options, Root root) => <Error>[];
+}
+
 /// A [GeneratorAdapter] that generates C++ source code.
 class CppGeneratorAdapter implements GeneratorAdapter {
   /// Constructor for [CppGeneratorAdapter].
@@ -630,7 +677,7 @@ class JnigenYamlGeneratorAdapter implements GeneratorAdapter {
   @override
   void generate(StringSink sink, InternalPigeonOptions options, Root root,
       FileType fileType) {
-    if (options.kotlinOptions == null) {
+    if (options.kotlinOptions == null || options.dartOptions == null) {
       return;
     }
     final JnigenYamlGenerator generator = JnigenYamlGenerator();
@@ -640,7 +687,7 @@ class JnigenYamlGeneratorAdapter implements GeneratorAdapter {
       options.kotlinOptions!,
       options.basePath,
       options.dartOptions?.dartOut,
-      options.kotlinOptions!.exampleAppDirectory,
+      options.kotlinOptions!.appDirectory,
     );
 
     generator.generate(
@@ -656,7 +703,7 @@ class JnigenYamlGeneratorAdapter implements GeneratorAdapter {
       options.kotlinOptions?.kotlinOut != null &&
               (options.kotlinOptions?.useJni ?? false)
           ? _openSink('jnigen.yaml',
-              basePath: options.kotlinOptions?.exampleAppDirectory ?? '')
+              basePath: options.kotlinOptions?.appDirectory ?? '')
           : null;
 
   @override

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

@@ -0,0 +1,161 @@
+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:path/path.dart' as path;
+
+import '../ast.dart';
+import '../dart/dart_generator.dart' show InternalDartOptions;
+import '../generator.dart';
+import '../generator_tools.dart';
+import 'swift_generator.dart' show InternalSwiftOptions;
+
+/// Options for [FfigenConfigGenerator].
+class InternalFfigenConfigOptions extends InternalOptions {
+  /// Creates a [InternalFfigenConfigOptions].
+  InternalFfigenConfigOptions(
+    this.dartOptions,
+    this.swiftOptions,
+    this.basePath,
+    this.dartOut,
+    this.exampleAppDirectory,
+  );
+
+  /// Dart options.
+  final InternalDartOptions dartOptions;
+
+  /// Swift options.
+  final InternalSwiftOptions swiftOptions;
+
+  /// A base path to be prepended to all provided output paths.
+  final String? basePath;
+
+  /// Dart output path.
+  final String? dartOut;
+
+  /// Android example app directory.
+  final String? exampleAppDirectory;
+}
+
+/// Generator for jnigen yaml configuration file.
+class FfigenConfigGenerator extends Generator<InternalFfigenConfigOptions> {
+  @override
+  void generate(
+      InternalFfigenConfigOptions generatorOptions, Root root, StringSink sink,
+      {required String dartPackageName}) {
+    final Indent indent = Indent(sink);
+
+    indent.format('''
+import 'dart:io';
+
+import 'package:ffigen/ffigen.dart' as fg;
+import 'package:logging/logging.dart';
+import 'package:pub_semver/pub_semver.dart';
+import 'package:swiftgen/swiftgen.dart';
+
+Future<void> main() async {
+  // TODO(https://github.com/dart-lang/native/issues/2371): Remove this.
+  Logger.root.onRecord.listen((record) {
+    stderr.writeln('\${record.level.name}: \${record.message}');
+  });
+
+  await SwiftGen(
+    target: Target(
+      triple: 'x86_64-apple-macosx14.0',
+      sdk: Uri.directory(
+        '/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk',
+      ),
+    ),
+    input: ObjCCompatibleSwiftFileInput(
+      module: 'AVFAudio',
+      files: [Uri.file('avf_audio_wrapper.swift')],
+    ),
+    tempDirectory: Uri.directory('temp'),
+    outputModule: 'AVFAudioWrapper',
+    ffigen: FfiGenConfig(
+      output: Uri.file('avf_audio_bindings.dart'),
+      outputObjC: Uri.file('avf_audio_wrapper.m'),
+      externalVersions: fg.ExternalVersions(
+        ios: fg.Versions(min: Version(12, 0, 0)),
+        macos: fg.Versions(min: Version(10, 14, 0)),
+      ),
+      objcInterfaces: fg.DeclarationFilters(
+        shouldInclude: (decl) => decl.originalName == 'AVAudioPlayerWrapper',
+      ),
+      preamble: \'''
+// Copyright (c) 2025, 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.
+
+// ignore_for_file: always_specify_types
+// ignore_for_file: camel_case_types
+// ignore_for_file: non_constant_identifier_names
+// ignore_for_file: unnecessary_non_null_assertion
+// ignore_for_file: unused_element
+// ignore_for_file: unused_field
+// coverage:ignore-file
+\''',
+    ),
+  ).generate();
+
+  final result = Process.runSync('swiftc', [
+    '-emit-library',
+    '-o',
+    'avf_audio_wrapper.dylib',
+    '-module-name',
+    'AVFAudioWrapper',
+    'avf_audio_wrapper.swift',
+    '-framework',
+    'AVFAudio',
+    '-framework',
+    'Foundation',
+  ]);
+  if (result.exitCode != 0) {
+    print('Failed to build the swift wrapper library');
+    print(result.stdout);
+    print(result.stderr);
+  }
+}
+      // name: SwiftLibrary
+      // language: swift
+      // output: '${path.posix.join(generatorOptions.basePath ?? '', path.withoutExtension(generatorOptions.dartOut ?? ''))}.ffi.dart'
+      // exclude-all-by-default: true
+      // headers:
+      //   entry-points:
+      //     - '${generatorOptions.swiftOptions.swiftOut}'
+      // preamble: |
+      //   # Header input
+
+      //   // ignore_for_file: camel_case_types, non_constant_identifier_names
+      //   // ignore_for_file: unused_element, unused_field, return_of_invalid_type
+      //   // ignore_for_file: void_checks, annotate_overrides
+      //   // ignore_for_file: no_leading_underscores_for_local_identifiers
+      //   // ignore_for_file: library_private_types_in_public_api
+
+      ''');
+    indent.writeScoped('// objc-interfaces:', '', () {
+      indent.writeScoped('// include:', '', () {
+        for (final Api api in root.apis) {
+          if (api is AstHostApi || api is AstFlutterApi) {
+            indent.writeln("// - '${api.name}'");
+            indent.writeln("// - '${api.name}Registrar'");
+          }
+        }
+        for (final Class dataClass in root.classes) {
+          indent.writeln("// - '${dataClass.name}'");
+        }
+        for (final Enum enumType in root.enums) {
+          indent.writeln("// - '${enumType.name}'");
+        }
+      });
+      indent.writeScoped('// include:', '', () {
+        for (final Class dataClass in root.classes) {
+          indent.writeln("// '${dataClass.name}': '${dataClass.name}'");
+        }
+        for (final Enum enumType in root.enums) {
+          indent.writeln("// '${enumType.name}': '${enumType.name}'");
+        }
+      });
+    });
+  }
+}