packages/pigeon/tool/shared/generation.dart

// 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 p;
import 'package:pigeon/pigeon.dart';

enum GeneratorLanguages {
  cpp,
  java,
  kotlin,
  objc,
  swift,
}

// A map of pigeons/ files to the languages that they can't yet be generated
// for due to limitations of that generator.
const Map<String, Set<GeneratorLanguages>> _unsupportedFiles =
    <String, Set<GeneratorLanguages>>{
  'enum_args': <GeneratorLanguages>{GeneratorLanguages.cpp},
};

String _snakeToPascalCase(String snake) {
  final List<String> parts = snake.split('_');
  return parts
      .map((String part) =>
          part.substring(0, 1).toUpperCase() + part.substring(1))
      .join();
}

// Remaps some file names for Java output, since the filename on Java will be
// the name of the generated top-level class. In some cases this is necessary
// (e.g., "list", which collides with the Java List class in tests), and in
// others it is just preserving previous behavior from the earlier Bash version
// of the generation to minimize churn during the migration.
// TODO(stuartmorgan): Remove the need for this when addressing
// https://github.com/flutter/flutter/issues/115168.
String _javaFilenameForName(String inputName) {
  const Map<String, String> specialCases = <String, String>{
    'android_unittests': 'Pigeon',
    'host2flutter': 'Host2Flutter',
    'list': 'PigeonList',
    'message': 'MessagePigeon',
    'voidflutter': 'VoidFlutter',
    'voidhost': 'VoidHost',
  };
  return specialCases[inputName] ?? _snakeToPascalCase(inputName);
}

Future<int> generatePigeons({required String baseDir}) async {
  // TODO(stuartmorgan): Make this dynamic rather than hard-coded. Or eliminate
  // it entirely; see https://github.com/flutter/flutter/issues/115169.
  const List<String> inputs = <String>[
    'android_unittests',
    'async_handlers',
    'background_platform_channels',
    'core_tests',
    'enum_args',
    'enum',
    'host2flutter',
    'java_double_host_api',
    'list',
    'message',
    'multiple_arity',
    'non_null_fields',
    'null_fields',
    'nullable_returns',
    'primitive',
    'void_arg_flutter',
    'void_arg_host',
    'voidflutter',
    'voidhost',
  ];

  final String outputBase = p.join(baseDir, 'platform_tests', 'test_plugin');
  final String alternateOutputBase =
      p.join(baseDir, 'platform_tests', 'alternate_language_test_plugin');
  final String sharedDartOutputBase =
      p.join(baseDir, 'platform_tests', 'shared_test_plugin_code');

  for (final String input in inputs) {
    final String pascalCaseName = _snakeToPascalCase(input);
    final Set<GeneratorLanguages> skipLanguages =
        _unsupportedFiles[input] ?? <GeneratorLanguages>{};

    // Generate the default language test plugin output.
    int generateCode = await runPigeon(
      input: './pigeons/$input.dart',
      dartOut: '$sharedDartOutputBase/lib/src/generated/$input.gen.dart',
      // Android
      kotlinOut: skipLanguages.contains(GeneratorLanguages.kotlin)
          ? null
          : '$outputBase/android/src/main/kotlin/com/example/test_plugin/$pascalCaseName.gen.kt',
      kotlinPackage: 'com.example.test_plugin',
      // iOS
      swiftOut: skipLanguages.contains(GeneratorLanguages.swift)
          ? null
          : '$outputBase/ios/Classes/$pascalCaseName.gen.swift',
      // Windows
      cppHeaderOut: skipLanguages.contains(GeneratorLanguages.cpp)
          ? null
          : '$outputBase/windows/pigeon/$input.gen.h',
      cppSourceOut: skipLanguages.contains(GeneratorLanguages.cpp)
          ? null
          : '$outputBase/windows/pigeon/$input.gen.cpp',
      cppNamespace: '${input}_pigeontest',
    );
    if (generateCode != 0) {
      return generateCode;
    }

    // macOS has to be run as a separate generation, since currently Pigeon
    // doesn't have a way to output separate macOS and iOS Swift output in a
    // single invocation.
    generateCode = await runPigeon(
      input: './pigeons/$input.dart',
      swiftOut: skipLanguages.contains(GeneratorLanguages.swift)
          ? null
          : '$outputBase/macos/Classes/$pascalCaseName.gen.swift',
    );
    if (generateCode != 0) {
      return generateCode;
    }

    // Generate the alternate language test plugin output.
    generateCode = await runPigeon(
      input: './pigeons/$input.dart',
      // Android
      // This doesn't use the '.gen' suffix since Java has strict file naming
      // rules.
      javaOut: skipLanguages.contains(GeneratorLanguages.java)
          ? null
          : '$alternateOutputBase/android/src/main/java/com/example/'
              'alternate_language_test_plugin/${_javaFilenameForName(input)}.java',
      javaPackage: 'com.example.alternate_language_test_plugin',
      // iOS
      objcHeaderOut: skipLanguages.contains(GeneratorLanguages.objc)
          ? null
          : '$alternateOutputBase/ios/Classes/$pascalCaseName.gen.h',
      objcSourceOut: skipLanguages.contains(GeneratorLanguages.objc)
          ? null
          : '$alternateOutputBase/ios/Classes/$pascalCaseName.gen.m',
    );
    if (generateCode != 0) {
      return generateCode;
    }
  }
  return 0;
}

Future<int> runPigeon({
  required String input,
  String? kotlinOut,
  String? kotlinPackage,
  String? swiftOut,
  String? cppHeaderOut,
  String? cppSourceOut,
  String? cppNamespace,
  String? dartOut,
  String? dartTestOut,
  String? javaOut,
  String? javaPackage,
  String? objcHeaderOut,
  String? objcSourceOut,
}) async {
  return Pigeon.runWithOptions(PigeonOptions(
    input: input,
    copyrightHeader: './copyright_header.txt',
    dartOut: dartOut,
    dartTestOut: dartTestOut,
    dartOptions: const DartOptions(),
    cppHeaderOut: cppHeaderOut,
    cppSourceOut: cppSourceOut,
    cppOptions: CppOptions(namespace: cppNamespace),
    javaOut: javaOut,
    javaOptions: JavaOptions(package: javaPackage),
    kotlinOut: kotlinOut,
    kotlinOptions: KotlinOptions(package: kotlinPackage),
    objcHeaderOut: objcHeaderOut,
    objcSourceOut: objcSourceOut,
    objcOptions: const ObjcOptions(),
    swiftOut: swiftOut,
    swiftOptions: const SwiftOptions(),
  ));
}