Adding initial support for DDC's Library Bundler module system to webdev.

dwds/CHANGELOG.md

@@ -3,6 +3,7 @@
 - Bump `build_web_compilers` to ^4.4.1.
 - Remove unused `clientFuture` arg from `DwdsVmClient` methods.
 - Fix pausing starting of `main` after the hot restart.
+- Updating bootstrapper for DDC library bundler module format + Frontend Server.
 
 ## 26.2.2
 

dwds/lib/src/loaders/ddc_library_bundle.dart

@@ -195,15 +195,19 @@ class DdcLibraryBundleStrategy extends LoadStrategy {
     modulePaths.forEach((name, path) {
       scripts.add(<String, String>{'src': '$path.js', 'id': name});
     });
-    return '''
-$baseUrlScript
+    // canary-mode uses the Frontend Server, which begins script loads via a
+    // separate pathway.
+    final scriptLoader = buildSettings.canaryFeatures
+        ? '''
 var scripts = ${const JsonEncoder.withIndent(" ").convert(scripts)};
 window.\$dartLoader.loadConfig.loadScriptFn = function(loader) {
   loader.addScriptsToQueue(scripts, null);
   loader.loadEnqueuedModules();
 };
 window.\$dartLoader.loader.nextAttempt();
-''';
+'''
+        : '';
+    return '$baseUrlScript\n$scriptLoader';
   }
 
   @override

webdev/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 3.8.1-wip
+
+- Adding initial DDC library bundler support behind the `canary` flag.
+
 ## 3.8.0-wip
 
 - Bump minimum SDK constraint to 3.10.0

webdev/lib/src/command/build_command.dart

@@ -93,7 +93,8 @@ class BuildCommand extends Command<int> {
         DefaultBuildTarget(
           (b) => b
             ..target = configuration.outputInput
-            ..outputLocation = outputLocation?.toBuilder(),
+            ..outputLocation = outputLocation?.toBuilder()
+            ..reportChangedAssets = true,
         ),
       );
       client.startBuild();

webdev/lib/src/command/shared.dart

@@ -126,6 +126,24 @@ List<String> buildRunnerArgs(Configuration configuration) {
     arguments.add('--enable-experiment=$experiment');
   }
 
+  if (configuration.canaryFeatures) {
+    arguments
+      ..add('--define')
+      ..add('build_web_compilers|sdk_js=web-hot-reload=true');
+    arguments
+      ..add('--define')
+      ..add('build_web_compilers|entrypoint=web-hot-reload=true');
+    arguments
+      ..add('--define')
+      ..add('build_web_compilers|entrypoint_marker=web-hot-reload=true');
+    arguments
+      ..add('--define')
+      ..add('build_web_compilers|ddc=web-hot-reload=true');
+    arguments
+      ..add('--define')
+      ..add('build_web_compilers|ddc_modules=web-hot-reload=true');
+  }
+
   return arguments;
 }
 

webdev/lib/src/serve/dev_workflow.dart

@@ -144,7 +144,8 @@ void _registerBuildTargets(
       DefaultBuildTarget(
         (b) => b
           ..target = target
-          ..outputLocation = outputLocation?.toBuilder(),
+          ..outputLocation = outputLocation?.toBuilder()
+          ..reportChangedAssets = true,
       ),
     );
   }
@@ -161,7 +162,8 @@ void _registerBuildTargets(
       DefaultBuildTarget(
         (b) => b
           ..target = ''
-          ..outputLocation = outputLocation.toBuilder(),
+          ..outputLocation = outputLocation.toBuilder()
+          ..reportChangedAssets = true,
       ),
     );
   }

webdev/lib/src/serve/utils.dart

@@ -106,3 +106,27 @@ String? findPackageConfigFilePath() {
     candidateDir = parentDir;
   }
 }
+
+/// Returns the absolute file path of the `package_config.json` file in the `.dart_tool`
+/// directory, searching recursively from the current directory hierarchy.
+Uri? findPackageConfigUri() {
+  var candidateDir = Directory(p.current).absolute;
+
+  while (true) {
+    final candidatePackageConfigFile = File(
+      p.join(candidateDir.path, '.dart_tool', 'package_config.json'),
+    );
+
+    if (candidatePackageConfigFile.existsSync()) {
+      return candidatePackageConfigFile.uri;
+    }
+
+    final parentDir = candidateDir.parent;
+    if (parentDir.path == candidateDir.path) {
+      // We've reached the root directory
+      return null;
+    }
+
+    candidateDir = parentDir;
+  }
+}

webdev/lib/src/serve/webdev_server.dart

@@ -3,13 +3,15 @@
 // BSD-style license that can be found in the LICENSE file.
 
 import 'dart:async';
+import 'dart:convert';
 import 'dart:io';
 
 import 'package:build_daemon/data/build_status.dart' as daemon;
 import 'package:dds/devtools_server.dart';
 import 'package:dwds/data/build_result.dart';
 import 'package:dwds/dwds.dart';
 import 'package:dwds/sdk_configuration.dart';
+import 'package:file/local.dart';
 import 'package:http/http.dart' as http;
 import 'package:http/io_client.dart';
 import 'package:http_multi_server/http_multi_server.dart';
@@ -21,10 +23,14 @@ import '../command/configuration.dart';
 import '../util.dart';
 import 'chrome.dart';
 import 'handlers/favicon_handler.dart';
-import 'utils.dart' show findPackageConfigFilePath;
+import 'utils.dart' show findPackageConfigFilePath, findPackageConfigUri;
 
 Logger _logger = Logger('WebDevServer');
 
+const reloadedSourcesFileName = 'reloaded_sources.json';
+const jsLibraryBundleExtension = '.ddc.js';
+const multiRootScheme = 'org-dartlang-app';
+
 class ServerOptions {
   final Configuration configuration;
   final int port;
@@ -80,6 +86,7 @@ class WebDevServer {
     ServerOptions options,
     Stream<daemon.BuildResults> buildResults,
   ) async {
+    final basePath = 'http://localhost:${options.port}';
     var pipeline = const Pipeline();
 
     if (options.configuration.logRequests) {
@@ -88,8 +95,47 @@ class WebDevServer {
 
     pipeline = pipeline.addMiddleware(interceptFavicon);
 
+    /// JSON-ifiable list of sources that were reloaded in this restart and
+    /// follows the following format:
+    ///
+    /// `src`: A string that corresponds to the file path containing a DDC library
+    /// bundle. To support embedded libraries, the path should include the
+    /// `baseUri` of the web server.
+    /// `module`: The name of the library bundle in `src`.
+    /// `libraries`: An array of strings containing the libraries that were
+    /// compiled in `src`.
+    ///
+    /// For example:
+    /// ```json
+    /// [
+    ///   {
+    ///     "src": "<baseUri>/<file_name>",
+    ///     "module": "<module_name>",
+    ///     "libraries": ["<lib1>", "<lib2>"],
+    ///   },
+    /// ]
+    /// ```
+    ///
+    /// The path of the output file should stay consistent across the lifetime of
+    /// the app.
+    final reloadedSources = <Map<String, dynamic>>[];
+
     // Only provide relevant build results
     final filteredBuildResults = buildResults.asyncMap<BuildResult>((results) {
+      if (options.configuration.canaryFeatures) {
+        // Clear reloaded sources for the new build results.
+        reloadedSources.clear();
+        results.changedAssets?.forEach((uri) {
+          if (uri.path.endsWith(jsLibraryBundleExtension)) {
+            final reloadedSource = {
+              'src': ddcUriToSourceUrl(basePath, options.target, uri),
+              'module': ddcUriToLibraryId(uri),
+              'libraries': [ddcUriToLibraryId(uri)],
+            };
+            reloadedSources.add(reloadedSource);
+          }
+        });
+      }
       final result = results.results.firstWhere(
         (result) => result.target == options.target,
       );
@@ -132,20 +178,39 @@ class WebDevServer {
       // the load strategy?
       final buildSettings = BuildSettings(
         appEntrypoint: Uri.parse(
-          'org-dartlang-app:///${options.target}/main.dart',
+          '$multiRootScheme:///${options.target}/main.dart',
         ),
         canaryFeatures: options.configuration.canaryFeatures,
         isFlutterApp: false,
         experiments: options.configuration.experiments,
       );
 
-      final loadStrategy = BuildRunnerRequireStrategyProvider(
-        assetHandler,
-        options.configuration.reload,
-        assetReader,
-        buildSettings,
-        packageConfigPath: findPackageConfigFilePath(),
-      ).strategy;
+      final LoadStrategy loadStrategy;
+      if (options.configuration.canaryFeatures) {
+        final frontendServerFileSystem = LocalFileSystem();
+        final packageUriMapper = await PackageUriMapper.create(
+          frontendServerFileSystem,
+          findPackageConfigUri()!,
+          useDebuggerModuleNames: false,
+        );
+        loadStrategy = FrontendServerDdcLibraryBundleStrategyProvider(
+          options.configuration.reload,
+          assetReader,
+          packageUriMapper,
+          () async => {},
+          buildSettings,
+          packageConfigPath: findPackageConfigFilePath(),
+          reloadedSourcesUri: Uri.parse('$basePath/$reloadedSourcesFileName'),
+        ).strategy;
+      } else {
+        loadStrategy = BuildRunnerRequireStrategyProvider(
+          assetHandler,
+          options.configuration.reload,
+          assetReader,
+          buildSettings,
+          packageConfigPath: findPackageConfigFilePath(),
+        ).strategy;
+      }
 
       if (options.configuration.enableExpressionEvaluation) {
         ddcService = ExpressionCompilerService(
@@ -161,8 +226,10 @@ class WebDevServer {
       final debugSettings = DebugSettings(
         enableDebugExtension: options.configuration.debugExtension,
         enableDebugging: options.configuration.debug,
+        // ignore: deprecated_member_use
         spawnDds: !options.configuration.disableDds,
         expressionCompiler: ddcService,
+        // ignore: deprecated_member_use
         devToolsLauncher: shouldServeDevTools
             ? (String hostname) async {
                 final server = await DevToolsServer().serveDevTools(
@@ -191,6 +258,18 @@ class WebDevServer {
       );
       pipeline = pipeline.addMiddleware(dwds.middleware);
       cascade = cascade.add(dwds.handler);
+      if (options.configuration.canaryFeatures) {
+        // Add a handler to serve reloaded sources.
+        cascade = cascade.add((Request request) {
+          if (request.url.path == reloadedSourcesFileName) {
+            return Response.ok(
+              jsonEncode(reloadedSources),
+              headers: {'Content-Type': 'application/json'},
+            );
+          }
+          return Response.notFound('');
+        });
+      }
       cascade = cascade.add(assetHandler);
     } else {
       cascade = cascade.add(assetHandler);
@@ -233,3 +312,58 @@ class WebDevServer {
     );
   }
 }
+
+/// Transforms a package:build JS asset id [uri] into a source url compatible
+/// with DDC's bootstrapper.
+///
+/// [basePath] is the path from which JS files as served up to but not
+/// including the path.
+/// [target] is the path whose files will be served from [basePath].
+/// [uri] is the asset id's uri being transformed.
+///
+/// Example:
+/// basePath: http://localhost:8080
+/// target: web
+///
+/// uri: asset:some_package/web/main.ddc.js
+/// returns http://localhost:8080/main.ddc.js
+///
+/// uri: package:some_package/src/sub_dir/file.ddc.js
+/// returns http://localhost:8080/some_package/src/sub_dir/file.ddc.js
+String ddcUriToSourceUrl(String basePath, String target, Uri uri) {
+  String jsPath;
+  if (uri.isScheme('asset')) {
+    // This indicates that this asset is the 'main' web asset. We directly
+    // serve all files under the package's [target] directory.
+    var pathParts = uri.pathSegments.skip(1);
+    if (pathParts.first == target) {
+      pathParts = pathParts.skip(1);
+    }
+    jsPath = pathParts.join('/');
+  } else if (uri.isScheme('package')) {
+    jsPath = 'packages/${uri.path}';
+  } else {
+    jsPath = uri.path;
+  }
+  return '$basePath/$jsPath';
+}
+
+/// Transforms a package:build JS asset id [uri] into a library id compatible
+/// with DDC's bootstrapper.
+///
+/// Example:
+/// uri: asset:some_package/web/main.ddc.js
+/// returns org-dartlang-app:///web/main.dart
+///
+/// uri: package:some_package/src/sub_dir/file.ddc.js
+/// returns package:some_package/src/sub_dir/file.dart
+String ddcUriToLibraryId(Uri uri) {
+  final jsPath = uri.isScheme('package')
+      ? 'package:${uri.path}'
+      : '$multiRootScheme:///${uri.path}';
+  final prefix = jsPath.substring(
+    0,
+    jsPath.length - jsLibraryBundleExtension.length,
+  );
+  return '$prefix.dart';
+}

webdev/pubspec.yaml

@@ -1,6 +1,6 @@
 name: webdev
 # Every time this changes you need to run `dart run build_runner build`.
-version: 3.8.0-wip
+version: 3.8.1-wip
 # We should not depend on a dev SDK before publishing.
 # publish_to: none
 description: >-
@@ -19,7 +19,8 @@ dependencies:
   crypto: ^3.0.2
   dds: ^4.1.0
   # Pin DWDS to avoid dependency conflicts with vm_service:
-  dwds: 24.3.11
+  dwds: ^25.0.0
+  file: ^7.0.1
   http: ^1.0.0
   http_multi_server: ^3.2.0
   io: ^1.0.3