Consolidate FrontendServerDdcStrategyProvider and FrontendServerRequireStrategyProvider under a shared parent class. - [#2517](https://gith… (#2518)

* Consolidate  and  under a shared parent class. - [#2517](#2517)

* clean up lib/src/loaders/frontend_server_strategy_provider.dart

* updated copyright date, make T extend loadstrategy and define strategies as late

* code formatting

* combine load strategies into one file and make fields/methods private

* updated path to load strategy providers and added a throw statement when new module format (ddc library bundle) is requested

Author: jyameo

dwds/CHANGELOG.md

@@ -1,5 +1,6 @@
 ## 24.2.0-wip
 
+- Consolidate `FrontendServerDdcStrategyProvider` and `FrontendServerRequireStrategyProvider` under a shared parent class. - [#2517](https://github.com/dart-lang/webdev/issues/2517)
 - Remove `build_daemon_ddc_and_canary_evaluate_test`. - [2512](https://github.com/dart-lang/webdev/issues/2512)
 - Replace deprecated JS code `this.__proto__` with `Object.getPrototypeOf(this)`. - [#2500](https://github.com/dart-lang/webdev/pull/2500)
 - Migrate injected client code to `package:web`. - [#2491](https://github.com/dart-lang/webdev/pull/2491)

dwds/lib/dwds.dart

@@ -20,10 +20,10 @@ export 'src/handlers/socket_connections.dart';
 export 'src/loaders/build_runner_require.dart'
     show BuildRunnerRequireStrategyProvider;
 export 'src/loaders/ddc.dart' show DdcStrategy;
-export 'src/loaders/frontend_server_ddc.dart'
-    show FrontendServerDdcStrategyProvider;
-export 'src/loaders/frontend_server_require.dart'
-    show FrontendServerRequireStrategyProvider;
+export 'src/loaders/frontend_server_strategy_provider.dart'
+    show
+        FrontendServerDdcStrategyProvider,
+        FrontendServerRequireStrategyProvider;
 export 'src/loaders/require.dart' show RequireStrategy;
 export 'src/loaders/strategy.dart'
     show LoadStrategy, ReloadConfiguration, BuildSettings;

dwds/lib/src/loaders/frontend_server_require.dart

@@ -1,51 +1,35 @@
-// Copyright 2023 The Dart Authors. All rights reserved.
+// Copyright 2024 The Dart 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:dwds/src/debugging/metadata/provider.dart';
 import 'package:dwds/src/loaders/ddc.dart';
+import 'package:dwds/src/loaders/require.dart';
 import 'package:dwds/src/loaders/strategy.dart';
 import 'package:dwds/src/readers/asset_reader.dart';
 import 'package:dwds/src/services/expression_compiler.dart';
 import 'package:path/path.dart' as p;
 
-/// Provides a [DdcStrategy] suitable for use with Frontend Server.
-class FrontendServerDdcStrategyProvider {
+abstract class FrontendServerStrategyProvider<T extends LoadStrategy> {
   final ReloadConfiguration _configuration;
   final AssetReader _assetReader;
   final PackageUriMapper _packageUriMapper;
   final Future<Map<String, String>> Function() _digestsProvider;
   final String _basePath;
   final BuildSettings _buildSettings;
 
-  late final DdcStrategy _ddcStrategy = DdcStrategy(
-    _configuration,
-    _moduleProvider,
-    (_) => _digestsProvider(),
-    _moduleForServerPath,
-    _serverPathForModule,
-    _sourceMapPathForModule,
-    _serverPathForAppUri,
-    _moduleInfoForProvider,
-    _assetReader,
-    _buildSettings,
-    (String _) => null,
-    null,
-  );
-
-  FrontendServerDdcStrategyProvider(
+  FrontendServerStrategyProvider(
     this._configuration,
     this._assetReader,
     this._packageUriMapper,
     this._digestsProvider,
     this._buildSettings,
   ) : _basePath = _assetReader.basePath;
 
-  DdcStrategy get strategy => _ddcStrategy;
+  T get strategy;
 
   String _removeBasePath(String path) {
     if (_basePath.isEmpty) return path;
-
     final stripped = stripLeadingSlashes(path);
     return stripLeadingSlashes(stripped.substring(_basePath.length));
   }
@@ -54,12 +38,15 @@ class FrontendServerDdcStrategyProvider {
       ? stripLeadingSlashes(serverPath)
       : '$_basePath/${stripLeadingSlashes(serverPath)}';
 
+  String _removeJsExtension(String path) =>
+      path.endsWith('.js') ? p.withoutExtension(path) : path;
+
   Future<Map<String, String>> _moduleProvider(
     MetadataProvider metadataProvider,
   ) async =>
       (await metadataProvider.moduleToModulePath).map(
         (key, value) =>
-            MapEntry(key, stripLeadingSlashes(removeJsExtension(value))),
+            MapEntry(key, stripLeadingSlashes(_removeJsExtension(value))),
       );
 
   Future<String?> _moduleForServerPath(
@@ -114,3 +101,61 @@ class FrontendServerDdcStrategyProvider {
     return result;
   }
 }
+
+/// Provides a [DdcStrategy] suitable for use with Frontend Server.
+class FrontendServerDdcStrategyProvider
+    extends FrontendServerStrategyProvider<DdcStrategy> {
+  late final DdcStrategy _ddcStrategy = DdcStrategy(
+    _configuration,
+    _moduleProvider,
+    (_) => _digestsProvider(),
+    _moduleForServerPath,
+    _serverPathForModule,
+    _sourceMapPathForModule,
+    _serverPathForAppUri,
+    _moduleInfoForProvider,
+    _assetReader,
+    _buildSettings,
+    (String _) => null,
+    null,
+  );
+
+  FrontendServerDdcStrategyProvider(
+    super._configuration,
+    super._assetReader,
+    super._packageUriMapper,
+    super._digestsProvider,
+    super._buildSettings,
+  );
+
+  @override
+  DdcStrategy get strategy => _ddcStrategy;
+}
+
+/// Provides a [RequireStrategy] suitable for use with Frontend Server.
+class FrontendServerRequireStrategyProvider
+    extends FrontendServerStrategyProvider<RequireStrategy> {
+  late final RequireStrategy _requireStrategy = RequireStrategy(
+    _configuration,
+    _moduleProvider,
+    (_) => _digestsProvider(),
+    _moduleForServerPath,
+    _serverPathForModule,
+    _sourceMapPathForModule,
+    _serverPathForAppUri,
+    _moduleInfoForProvider,
+    _assetReader,
+    _buildSettings,
+  );
+
+  FrontendServerRequireStrategyProvider(
+    super._configuration,
+    super._assetReader,
+    super._packageUriMapper,
+    super._digestsProvider,
+    super._buildSettings,
+  );
+
+  @override
+  RequireStrategy get strategy => _requireStrategy;
+}

dwds/lib/src/loaders/frontend_server_ddc.dart renamed to dwds/lib/src/loaders/frontend_server_strategy_provider.dart

@@ -15,8 +15,7 @@ import 'package:dwds/src/connections/app_connection.dart';
 import 'package:dwds/src/connections/debug_connection.dart';
 import 'package:dwds/src/debugging/webkit_debugger.dart';
 import 'package:dwds/src/loaders/build_runner_require.dart';
-import 'package:dwds/src/loaders/frontend_server_ddc.dart';
-import 'package:dwds/src/loaders/frontend_server_require.dart';
+import 'package:dwds/src/loaders/frontend_server_strategy_provider.dart';
 import 'package:dwds/src/loaders/strategy.dart';
 import 'package:dwds/src/readers/proxy_server_asset_reader.dart';
 import 'package:dwds/src/services/chrome_proxy_service.dart';
@@ -348,13 +347,18 @@ class TestContext {
                   () async => {},
                   buildSettings,
                 ).strategy,
-              ModuleFormat.ddc => FrontendServerDdcStrategyProvider(
-                  testSettings.reloadConfiguration,
-                  assetReader,
-                  packageUriMapper,
-                  () async => {},
-                  buildSettings,
-                ).strategy,
+              ModuleFormat.ddc => buildSettings.canaryFeatures
+                  ? throw Exception(
+                      '''Unsupported DDC module format ${testSettings.moduleFormat.name}
+                      with canaryFeatures set to ${buildSettings.canaryFeatures}.''',
+                    )
+                  : FrontendServerDdcStrategyProvider(
+                      testSettings.reloadConfiguration,
+                      assetReader,
+                      packageUriMapper,
+                      () async => {},
+                      buildSettings,
+                    ).strategy,
               _ => throw Exception(
                   'Unsupported DDC module format ${testSettings.moduleFormat.name}.',
                 )