[material_ui] Set up gen_defaults sub-directory

packages/material_ui/pubspec.yaml

@@ -11,6 +11,7 @@ environment:
 
 workspace:
   - example
+  - tool/gen_defaults
 
 dependencies:
   cupertino_ui:

packages/material_ui/tool/gen_defaults/README.md

@@ -0,0 +1,24 @@
+## Token Defaults Generator
+
+Script that generates component theme data defaults based on token data.
+
+## Usage
+Run this program from the root of the git repository:
+```sh
+dart packages/material_ui/tool/gen_defaults/bin/gen_defaults.dart [-v]
+```
+
+This updates generated component theming files under
+`packages/material_ui/lib/src/generated`.
+
+## Templates
+
+There is a template file for every component that needs defaults from the token
+database. These templates are implemented as subclasses of either `M3TokenTemplate` or `M3ETokenTemplate`.
+
+Templates need to override the `generateContents` method to provide the
+generated code block as a string.
+
+## Tokens
+
+Tokens are stored in `data/`, and are sourced from an internal Google database.

packages/material_ui/tool/gen_defaults/analysis_options.yaml

@@ -0,0 +1,4 @@
+include: ../../../../analysis_options.yaml
+
+formatter:
+  page_width: 100

packages/material_ui/tool/gen_defaults/bin/gen_defaults.dart

@@ -0,0 +1,28 @@
+// Copyright 2013 The Flutter Authors
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+//
+// ## Usage
+//
+// Run from the root of flutter/packages:
+//
+// ```
+// dart packages/material_ui/tool/gen_defaults/bin/gen_defaults.dart [-v]
+// ```
+
+import 'package:args/args.dart';
+
+// TODO(elliette): Import template files.
+// import '../templates/x_template.dart';
+
+Future<void> main(List<String> args) async {
+  // Parse arguments
+  final parser = ArgParser();
+  parser.addFlag('verbose', abbr: 'v', help: 'Enable verbose output', negatable: false);
+  final ArgResults argResults = parser.parse(args);
+  // TODO(elliette): Add token logger when verbose flag is used.
+  // ignore: unused_local_variable
+  final verbose = argResults['verbose'] as bool;
+  // TODO(elliette): Invoke template generators.
+  // const XTemplate().generateFile(verbose: verbose);
+}

packages/material_ui/tool/gen_defaults/pubspec.yaml

@@ -0,0 +1,17 @@
+name: gen_defaults
+description: A command line script to generate Material component defaults from the token database.
+publish_to: none
+version: 1.0.0
+
+environment:
+  sdk: ^3.10.0-0
+
+resolution: workspace
+
+dependencies:
+  args: any
+  meta: any
+
+dev_dependencies:
+  path: any
+  test: any

packages/material_ui/tool/gen_defaults/templates/template.dart

@@ -0,0 +1,111 @@
+// Copyright 2013 The Flutter Authors
+// 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:meta/meta.dart';
+
+enum _MaterialVersion { material3, material3Expressive }
+
+abstract class M3TokenTemplate extends _TokenTemplate {
+  const M3TokenTemplate();
+
+  @override
+  _MaterialVersion get _version => _MaterialVersion.material3;
+}
+
+abstract class M3ETokenTemplate extends _TokenTemplate {
+  const M3ETokenTemplate();
+
+  @override
+  _MaterialVersion get _version => _MaterialVersion.material3Expressive;
+}
+
+abstract class _TokenTemplate {
+  const _TokenTemplate();
+
+  static const String copyrightHeader = '''
+// Copyright 2013 The Flutter Authors
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+''';
+
+  static const String headerComment = '''
+
+// Do not edit by hand. The code is generated from data in the Material
+// Design token database by the script:
+//   packages/material_ui/tool/gen_defaults/bin/gen_defaults.dart.
+''';
+
+  /// The Material version this template is for.
+  _MaterialVersion get _version;
+
+  /// The name of the template, which corresponds to the target file name.
+  /// E.g., 'typography' for generating 'typography_defaults.g.dart'.
+  String get name;
+
+  @visibleForTesting
+  String get materialLib {
+    const packagePath = 'packages/material_ui';
+    const generatedDirectory = 'lib/src/generated';
+    final String relativeOutputPath = switch (_version) {
+      _MaterialVersion.material3 => generatedDirectory,
+      _MaterialVersion.material3Expressive => '$generatedDirectory/material_3_expressive',
+    };
+    if (Directory(packagePath).existsSync()) {
+      return '$packagePath/$relativeOutputPath';
+    }
+    return relativeOutputPath;
+  }
+
+  String generateContents();
+
+  void generateFile({bool verbose = false}) {
+    final fileName = '$materialLib/${name}_defaults.g.dart';
+    if (verbose) {
+      stdout.writeln('Generating file: $fileName');
+      stdout.writeln('Target parent file name: $name.dart');
+    }
+    final file = File(fileName);
+    if (!file.existsSync()) {
+      if (verbose) {
+        stdout.writeln('File does not exist, creating it.');
+      }
+      file.createSync(recursive: true);
+    }
+
+    final parentName = '$name.dart';
+
+    if (verbose) {
+      stdout.writeln('Generating contents...');
+    }
+    final buffer = StringBuffer();
+    buffer.write(copyrightHeader);
+    buffer.write(headerComment);
+    final String partOfPath = switch (_version) {
+      _MaterialVersion.material3 => '../$parentName',
+      _MaterialVersion.material3Expressive => '../../material_3_expressive/$parentName',
+    };
+    buffer.write("part of '$partOfPath';\n\n");
+    buffer.write(generateContents());
+
+    if (verbose) {
+      stdout.writeln('Writing generated contents to $fileName...');
+    }
+    file.writeAsStringSync(buffer.toString());
+    if (verbose) {
+      stdout.writeln('Formatting $fileName...');
+    }
+    final ProcessResult result = Process.runSync(Platform.resolvedExecutable, <String>[
+      'format',
+      fileName,
+    ]);
+    if (result.exitCode != 0) {
+      stderr.writeln('Failed to format $fileName: ${result.stderr}');
+    }
+    if (verbose) {
+      stdout.writeln('Done generating $fileName.');
+    }
+  }
+}

packages/material_ui/tool/gen_defaults/test/gen_defaults_test.dart

@@ -0,0 +1,112 @@
+// Copyright 2013 The Flutter Authors
+// 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:test/test.dart';
+import 'test_fixtures/test_templates.dart';
+
+void main() {
+  Directory? tempDir;
+  String testPath() => tempDir!.path;
+
+  group('gen_defaults templates', () {
+    setUp(() {
+      tempDir = Directory.systemTemp.createTempSync('gen_defaults');
+    });
+
+    tearDown(() {
+      tempDir!.deleteSync(recursive: true);
+    });
+
+    test('will generate a part file ending in _defaults.g.dart', () {
+      final template = ButtonTemplate(testPath());
+      template.generateFile(verbose: true);
+
+      final file = File('${testPath()}/button_defaults.g.dart');
+      expect(file.existsSync(), isTrue);
+    });
+
+    test('will generate a file with the correct header text', () {
+      final template = ButtonTemplate(testPath());
+      template.generateFile();
+
+      final file = File('${testPath()}/button_defaults.g.dart');
+      final String fileContents = file.readAsStringSync();
+      expect(fileContents, contains(_fileHeader));
+    });
+
+    test('will generate a file with the expected contents', () {
+      final template = ButtonTemplate(testPath());
+      template.generateFile();
+
+      final file = File('${testPath()}/button_defaults.g.dart');
+      final String fileContents = file.readAsStringSync();
+      expect(fileContents, contains(_buttonDefaultsClass));
+    });
+
+    test('will completely overwrite any previous code', () {
+      final file = File('${testPath()}/button_defaults.g.dart');
+      const randomText = 'Pre-existing random text.';
+      file.writeAsStringSync(randomText);
+
+      final template = ButtonTemplate(testPath());
+      template.generateFile();
+      final String fileContents = file.readAsStringSync();
+      expect(fileContents, isNot(contains(randomText)));
+      expect(fileContents, contains(_buttonDefaultsClass));
+    });
+
+    test('will run dart format over the generated file', () {
+      final template = UnformattedTemplate(testPath());
+      template.generateFile();
+
+      final file = File('${testPath()}/unformatted_defaults.g.dart');
+      expect(file.readAsStringSync(), contains(formattedClass));
+    });
+
+    test('materialLib path resolves correctly based on MaterialVersion', () {
+      final m3Template = TestM3Template();
+      final m3ExpressiveTemplate = TestM3ExpressiveTemplate();
+      const materialUiDir = 'packages/material_ui';
+      const generatedDir = 'lib/src/generated';
+
+      final bool hasPackageDir = Directory(materialUiDir).existsSync();
+      if (hasPackageDir) {
+        expect(m3Template.materialLib, '$materialUiDir/$generatedDir');
+        expect(
+          m3ExpressiveTemplate.materialLib,
+          '$materialUiDir/$generatedDir/material_3_expressive',
+        );
+      } else {
+        expect(m3Template.materialLib, generatedDir);
+        expect(m3ExpressiveTemplate.materialLib, '$generatedDir/material_3_expressive');
+      }
+    });
+  });
+}
+
+const _fileHeader = '''
+// Copyright 2013 The Flutter Authors
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Do not edit by hand. The code is generated from data in the Material
+// Design token database by the script:
+//   packages/material_ui/tool/gen_defaults/bin/gen_defaults.dart.
+''';
+
+const _buttonDefaultsClass = '''
+class _ButtonDefaults {
+  static const double height = 40.0;
+  static const double borderRadius = 8.0;
+}
+''';
+
+const formattedClass = '''
+class UnformattedClass {
+  final int x = 1;
+  final String y = 'hello';
+}
+''';

packages/material_ui/tool/gen_defaults/test/test_fixtures/button_token_data.dart

@@ -0,0 +1,8 @@
+// Copyright 2013 The Flutter Authors
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+class TokenButton {
+  static const double height = 40.0;
+  static const double borderRadius = 8.0;
+}

packages/material_ui/tool/gen_defaults/test/test_fixtures/test_templates.dart

@@ -0,0 +1,66 @@
+// Copyright 2013 The Flutter Authors
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import '../../templates/template.dart';
+import 'button_token_data.dart';
+
+class ButtonTemplate extends M3ETokenTemplate {
+  ButtonTemplate(this.customMaterialLib);
+
+  final String customMaterialLib;
+
+  @override
+  String get name => 'button';
+
+  @override
+  String get materialLib => customMaterialLib;
+
+  @override
+  String generateContents() {
+    return '''
+class _ButtonDefaults {
+  static const double height = ${TokenButton.height};
+  static const double borderRadius = ${TokenButton.borderRadius};
+}
+''';
+  }
+}
+
+class UnformattedTemplate extends M3TokenTemplate {
+  UnformattedTemplate(this.customMaterialLib);
+
+  final String customMaterialLib;
+
+  @override
+  String get name => 'unformatted';
+
+  @override
+  String get materialLib => customMaterialLib;
+
+  @override
+  String generateContents() {
+    return '''
+class   UnformattedClass   {
+final    int    x = 1  ;
+  final String y   =   'hello' ;
+}
+''';
+  }
+}
+
+class TestM3Template extends M3TokenTemplate {
+  @override
+  String get name => 'm3';
+
+  @override
+  String generateContents() => '';
+}
+
+class TestM3ExpressiveTemplate extends M3ETokenTemplate {
+  @override
+  String get name => 'm3e';
+
+  @override
+  String generateContents() => '';
+}