Build macros.

pkgs/_macro_builder/lib/macro_builder.dart

@@ -2,22 +2,98 @@
 // 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 'dart:io';
+
 import 'package:dart_model/dart_model.dart';
 
 class MacroBuilder {
   /// Builds an executable from user-written macro code.
   ///
   /// Each `QualifiedName` in [macroImplementations] must point to a class that
   /// implements `Macro` from `package:macro`.
+  ///
+  /// The [packageConfig] must include the macros and all their deps.
   Future<BuiltMacroBundle> build(
-      Iterable<QualifiedName> macroImplementations) async {
-    // TODO(davidmorgan): implement.
-    // Generated entrypoint will instantiate all the `Macro` instances pointed
-    // to by `macroImplementations` then pass them to `MacroClient.run` in
-    // `package:_macro_client`.
-    return BuiltMacroBundle();
+      File packageConfig, Iterable<QualifiedName> macroImplementations) async {
+    final script = createBootstrap(macroImplementations.toList());
+
+    return await MacroBuild(packageConfig, script).build();
+  }
+
+  static String createBootstrap(List<QualifiedName> macros) {
+    final script = StringBuffer();
+    for (var i = 0; i != macros.length; ++i) {
+      final macro = macros[i];
+      script.writeln("import '${macro.uri}' as m$i;");
+    }
+    script.write('''
+import 'dart:convert';
+
+import 'package:_macro_client/macro_client.dart';
+import 'package:macro_service/macro_service.dart';
+
+void main(List<String> arguments) {
+   MacroClient().run(
+      HostEndpoint.fromJson(json.decode(arguments[0])),
+     [''');
+    for (var i = 0; i != macros.length; ++i) {
+      final macro = macros[i];
+      script.write('m$i.${macro.name}()');
+      if (i != macros.length - 1) script.write(', ');
+    }
+    script.writeln(']);');
+    script.writeln('}');
+    return script.toString();
   }
 }
 
 /// A bundle of one or more macros that's ready to execute.
-class BuiltMacroBundle {}
+class BuiltMacroBundle {
+  // TODO(davidmorgan): other formats besides executable.
+  final String executablePath;
+
+  BuiltMacroBundle(this.executablePath);
+}
+
+/// A single build.
+class MacroBuild {
+  final File packageConfig;
+  final String script;
+  final Directory workspace =
+      Directory.systemTemp.createTempSync('macro_builder');
+
+  MacroBuild(this.packageConfig, this.script);
+
+  Future<BuiltMacroBundle> build() async {
+    final scriptFile = File.fromUri(workspace.uri.resolve('bin/main.dart'));
+    scriptFile.parent.createSync(recursive: true);
+    scriptFile.writeAsStringSync(script.toString());
+
+    // TODO(davidmorgan): replace relative paths to absolute.
+    final targetPackageConfig =
+        File.fromUri(workspace.uri.resolve('.dart_tool/package_config.json'));
+    targetPackageConfig.parent.createSync(recursive: true);
+    targetPackageConfig
+        .writeAsStringSync(_makePackageConfigAbsolute(packageConfig));
+
+    // See package:analyzer/src/summary2/kernel_compilation_service.dart for an
+    // example of compiling macros using the frontend server.
+    //
+    // For now just use the command line.
+
+    final result = Process.runSync('dart', ['compile', 'exe', 'bin/main.dart'],
+        workingDirectory: workspace.path);
+    if (result.exitCode != 0) {
+      throw StateError('Compile failed: ${result.stderr}');
+    }
+
+    return BuiltMacroBundle(scriptFile.parent.uri.resolve('main.exe').path);
+  }
+
+  String _makePackageConfigAbsolute(File pubspec) {
+    final root = pubspec.parent.parent.absolute.uri;
+    return pubspec
+        .readAsStringSync()
+        .replaceAll('"rootUri": "../', '"rootUri": "$root');
+  }
+}

pkgs/_macro_builder/mono_pkg.yaml

@@ -8,3 +8,8 @@ stages:
   - format:
     sdk:
     - dev
+- unit_test:
+  - test: --test-randomize-ordering-seed=random
+    os:
+    - linux
+    - windows

pkgs/_macro_builder/pubspec.yaml

@@ -13,3 +13,4 @@ dependencies:
 
 dev_dependencies:
   dart_flutter_team_lints: ^3.0.0
+  test: ^1.25.0

pkgs/_macro_builder/test/macro_builder_test.dart

@@ -0,0 +1,50 @@
+// 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 'dart:io';
+
+import 'package:_macro_builder/macro_builder.dart';
+import 'package:dart_model/dart_model.dart';
+import 'package:test/test.dart';
+
+void main() {
+  group(MacroBuilder, () {
+    test('bootstrap matches golden', () async {
+      final script = MacroBuilder.createBootstrap([
+        QualifiedName('package:_test_macros/declare_x_macro.dart#DeclareX'),
+        QualifiedName('package:_test_macros/declare_y_macro.dart#DeclareY'),
+        QualifiedName(
+            'package:_more_macros/other_macro.dart#OtherMacroImplementation')
+      ]);
+
+      expect(script, '''
+import 'package:_test_macros/declare_x_macro.dart' as m0;
+import 'package:_test_macros/declare_y_macro.dart' as m1;
+import 'package:_more_macros/other_macro.dart' as m2;
+import 'dart:convert';
+
+import 'package:_macro_client/macro_client.dart';
+import 'package:macro_service/macro_service.dart';
+
+void main(List<String> arguments) {
+   MacroClient().run(
+      HostEndpoint.fromJson(json.decode(arguments[0])),
+     [m0.DeclareX(), m1.DeclareY(), m2.OtherMacroImplementation()]);
+}
+''');
+    });
+
+    test('builds macros', () async {
+      final builder = MacroBuilder();
+
+      final bundle = await builder.build(
+          File.fromUri(Uri.parse('../../.dart_tool/package_config.json')), [
+        QualifiedName(
+            'package:_test_macros/declare_x_macro.dart#DeclareXImplementation')
+      ]);
+
+      expect(File(bundle.executablePath).existsSync(), true);
+    });
+  });
+}

pkgs/dart_model/lib/src/dart_model.dart

@@ -6,7 +6,7 @@ import 'dart_model.g.dart';
 
 export 'dart_model.g.dart';
 
-// TODO(davidmorgan): remove example when we have an actual extension method.
-extension ModelExtension on Model {
-  String get exampleGetter => 'exampleValue';
+extension QualifiedNameExtension on QualifiedName {
+  String get uri => string.substring(0, string.indexOf('#'));
+  String get name => string.substring(string.indexOf('#') + 1);
 }

pkgs/dart_model/test/model_test.dart

@@ -46,10 +46,6 @@ void main() {
       }
     };
 
-    test('has extension methods', () {
-      expect(model.exampleGetter, 'exampleValue');
-    });
-
     test('maps to JSON', () {
       expect(model as Map, expected);
     });
@@ -104,4 +100,15 @@ void main() {
               'JsonData']!['members']);
     });
   });
+
+  group(QualifiedName, () {
+    test('has uri', () {
+      expect(QualifiedName('package:foo/foo.dart#Foo').uri,
+          'package:foo/foo.dart');
+    });
+
+    test('has name', () {
+      expect(QualifiedName('package:foo/foo.dart#Foo').uri, 'Foo');
+    });
+  });
 }