pkgs/swift2objc/lib/src/config.dart

// 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 'package:path/path.dart' as path;

import 'ast/_core/interfaces/declaration.dart';

const defaultTempDirPrefix = 'swift2objc_temp_';
const symbolgraphFileSuffix = '.symbols.json';

class Command {
  final String executable;
  final List<String> args;

  Command({required this.executable, required this.args});
}

/// Used to configure Swift2ObjC wrapper generation.
class Swift2ObjCGenerator {
  /// The inputs to generate a wrapper for.
  /// See `FilesInputConfig` and `ModuleInputConfig`;
  final List<InputConfig> inputs;

  /// The target to generate code for. If unspecified, defaults to host.
  /// (e.g `x86_64-apple-ios17.0-simulator`)
  final String? target;

  /// The sdk to compile against. If unspecified, defaults to host.
  /// (e.g `/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator.sdk`)
  final Uri? sdk;

  /// Specify where the wrapper swift file will be output.
  final Uri outputFile;

  /// Text inserted into the [outputFile] before the generated output.
  final String? preamble;

  /// Specify where to output the intermidiate files (i.g the symbolgraph json).
  /// If this is null, a temp directory will be generated in the system temp
  /// directory (using `Directory.systemTemp`) and then deleted.
  /// Specifying a temp directory would prevent the tool from deleting the
  /// 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(Declaration _) => true;

  const Swift2ObjCGenerator({
    required this.inputs,
    required this.outputFile,
    this.target,
    this.sdk,
    this.tempDir,
    this.preamble,
    this.include = Swift2ObjCGenerator._defaultInclude,
  });
}

/// Used to specify the inputs in the `config` object.
sealed class InputConfig {}

/// Used for `InputConfig`s that use a command to generate their symbolgraph.
abstract interface class HasSymbolgraphCommand {
  Command symbolgraphCommand(String target, String sdkPath);
}

/// Used to generate a objc wrapper for one or more swift files.
class FilesInputConfig implements InputConfig, HasSymbolgraphCommand {
  /// The swift file(s) to generate a wrapper for.
  final List<Uri> files;

  /// The name of the temporary module generated while analyzing the input
  /// files. The name doesn't matter, and won't appear in generated code. But if
  /// your project involves multiple Swift modules, their names must be unique.
  final String tempModuleName;

  const FilesInputConfig({
    required this.files,
    this.tempModuleName = 'symbolgraph_module',
  });

  @override
  Command symbolgraphCommand(String target, String sdkPath) => Command(
    executable: 'swiftc',
    args: [
      ...files.map((uri) => path.absolute(uri.path)),
      '-emit-module',
      '-emit-symbol-graph',
      '-emit-symbol-graph-dir',
      '.',
      '-module-name',
      tempModuleName,
      '-target',
      target,
      '-sdk',
      sdkPath,
    ],
  );
}

/// Used to generate a objc wrapper for a built-in swift module.
/// (e.g, AVFoundation)
class ModuleInputConfig implements InputConfig, HasSymbolgraphCommand {
  /// The swift module to generate a wrapper for.
  final String module;

  const ModuleInputConfig({required this.module});

  @override
  Command symbolgraphCommand(String target, String sdkPath) => Command(
    executable: 'swift',
    args: [
      'symbolgraph-extract',
      '-module-name',
      module,
      '-target',
      target,
      '-sdk',
      sdkPath,
      '-output-dir',
      '.',
    ],
  );
}

/// Used to generate wrappers directly from a JSON symbolgraph, for debugging.
class JsonFileInputConfig implements InputConfig {
  /// The JSON symbolgraph file.
  final Uri jsonFile;

  const JsonFileInputConfig({required this.jsonFile});
}

const builtInInputConfig = ModuleInputConfig(module: 'Foundation');