DWDS Feature: Daemon Expression Compiler & FES Support

Author: Markzipan

dwds/lib/asset_reader.dart

@@ -3,4 +3,9 @@
 // BSD-style license that can be found in the LICENSE file.
 
 export 'src/readers/asset_reader.dart'
-    show AssetReader, PackageUriMapper, stripLeadingSlashes;
+    show
+        AssetReader,
+        BuildRunnerPathResolver,
+        FrontendServerPathResolver,
+        PathResolver,
+        stripLeadingSlashes;

dwds/lib/dwds.dart

@@ -18,13 +18,16 @@ export 'src/debugging/metadata/provider.dart'
 export 'src/events.dart' show DwdsEvent;
 export 'src/handlers/dev_handler.dart' show AppConnectionException;
 export 'src/handlers/socket_connections.dart';
+export 'src/loaders/asset_scheme.dart'
+    show AssetScheme, BuildRunnerAssetScheme, FrontendServerAssetScheme;
 export 'src/loaders/build_runner_strategy_provider.dart'
     show
         BuildRunnerDdcLibraryBundleStrategyProvider,
         BuildRunnerRequireStrategyProvider;
 export 'src/loaders/ddc.dart' show DdcStrategy;
 export 'src/loaders/frontend_server_strategy_provider.dart'
     show
+        FrontendServerBuildDaemonStrategyProvider,
         FrontendServerDdcLibraryBundleStrategyProvider,
         FrontendServerDdcStrategyProvider,
         FrontendServerRequireStrategyProvider;
@@ -35,13 +38,21 @@ export 'src/loaders/strategy.dart'
         LoadStrategy,
         ReloadConfiguration,
         ReloadableLoadStrategy;
-export 'src/readers/asset_reader.dart' show AssetReader, PackageUriMapper;
+export 'src/readers/asset_reader.dart'
+    show
+        AssetReader,
+        BuildRunnerPathResolver,
+        FlutterPathResolver,
+        FrontendServerPathResolver,
+        PathResolver;
 export 'src/readers/frontend_server_asset_reader.dart'
     show FrontendServerAssetReader;
 export 'src/readers/proxy_server_asset_reader.dart' show ProxyServerAssetReader;
 export 'src/servers/devtools.dart';
 export 'src/services/chrome/chrome_debug_exception.dart'
     show ChromeDebugException;
+export 'src/services/daemon_expression_compiler.dart'
+    show DaemonExpressionCompiler;
 export 'src/services/expression_compiler.dart'
     show
         CompilerOptions,

dwds/lib/src/debugging/location.dart

@@ -8,6 +8,7 @@ import 'package:dwds/src/debugging/metadata/provider.dart';
 import 'package:dwds/src/debugging/modules.dart';
 import 'package:dwds/src/readers/asset_reader.dart';
 import 'package:dwds/src/utilities/dart_uri.dart';
+import 'package:dwds/src/utilities/web_path_translator.dart';
 import 'package:logging/logging.dart';
 import 'package:path/path.dart' as p;
 import 'package:source_maps/parser.dart';
@@ -194,6 +195,8 @@ class Locations {
     return _sourceToLocation[serverPath] ?? {};
   }
 
+  Iterable<String> keys() => _sourceToLocation.keys;
+
   /// Returns all [Location] data for a provided JS server path.
   Future<Set<Location>> locationsForUrl(String url) async {
     if (url.isEmpty) return {};
@@ -345,7 +348,13 @@ class Locations {
         '/${stripLeadingSlashes(modulePath)}',
       );
 
-      if (sourceMapContents == null) return result;
+      if (sourceMapContents == null) {
+        _logger.warning(
+          'Failed to load source map for module $module at path '
+          '$sourceMapPath',
+        );
+        return result;
+      }
 
       final runtimeScriptId = await _modules.getRuntimeScriptIdForModule(
         _entrypoint,
@@ -373,11 +382,9 @@ class Locations {
         }
       }
       for (final location in result) {
+        final serverPath = location.dartLocation.uri.serverPath;
         _sourceToLocation
-            .putIfAbsent(
-              location.dartLocation.uri.serverPath,
-              () => <Location>{},
-            )
+            .putIfAbsent(serverPath, () => <Location>{})
             .add(location);
       }
       return _moduleToLocations[module] = result;
@@ -395,15 +402,25 @@ class Locations {
   }) {
     final index = entry.sourceUrlId;
     if (index == null) return null;
-    // Source map URLS are relative to the script. They may have platform
-    // separators or they may use URL semantics. To be sure, we split and
-    // re-join them.
-    // This works on Windows because path treats both / and \ as separators.
-    // It will fail if the path has both separators in it.
-    final relativeSegments = p.split(sourceUrls[index]);
-    final path = p.url.normalize(
-      p.url.joinAll([scriptLocation, ...relativeSegments]),
-    );
+    final sourceUrl = sourceUrls[index];
+    String path;
+    if (Uri.tryParse(sourceUrl)?.isAbsolute == true) {
+      path = sourceUrl;
+    } else {
+      // TODO(markzipan): Check if platform-specific separators can be handled
+      //  upstream in the SDK.
+      // Source map URLS are relative to the script. They may have platform
+      // separators or they may use URL semantics. To be sure, we split and
+      // re-join them.
+      // This works on Windows because path treats both / and \ as separators.
+      // It will fail if the path has both separators in it.
+      final relativeSegments = p.split(sourceUrl);
+      path = p.url.normalize(
+        p.url.joinAll([scriptLocation, ...relativeSegments]),
+      );
+
+      path = WebPathTranslator.reconstructAppScheme(path, scriptLocation);
+    }
 
     try {
       final dartUri = DartUri(path, _root);

dwds/lib/src/debugging/metadata/provider.dart

@@ -1,7 +1,6 @@
 // Copyright (c) 2020, 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:convert';
 
 import 'package:async/async.dart';
@@ -13,7 +12,6 @@ import 'package:path/path.dart' as p;
 /// A provider of metadata in which data is collected through DDC outputs.
 class MetadataProvider {
   final AssetReader _assetReader;
-  final _logger = Logger('MetadataProvider');
   final String entrypoint;
   final Set<String> _libraries = {};
   final Map<String, String> _scriptToModule = {};
@@ -165,13 +163,15 @@ class MetadataProvider {
   /// return a map from module names to their [ModuleMetadata].
   Future<Map<String, ModuleMetadata>> _processMetadata() async {
     final modules = <String, ModuleMetadata>{};
-    // The merged metadata resides next to the entrypoint.
-    // Assume that <name>.bootstrap.js has <name>.ddc_merged_metadata
-    if (entrypoint.endsWith('.bootstrap.js')) {
-      _logger.info('Loading debug metadata...');
+    final logger = Logger('MetadataProvider');
+    final assetScheme = _assetReader.assetScheme;
+    final bootstrapSuffix = assetScheme.bootstrapSuffix;
+
+    if (entrypoint.endsWith(bootstrapSuffix)) {
+      logger.info('Loading debug metadata...');
       final serverPath = entrypoint.replaceAll(
-        '.bootstrap.js',
-        '.ddc_merged_metadata',
+        bootstrapSuffix,
+        assetScheme.mergedMetadataSuffix,
       );
       final merged = await _assetReader.metadataContents(serverPath);
       if (merged != null) {
@@ -187,10 +187,9 @@ class MetadataProvider {
             );
             final moduleName = metadata.name;
             modules[moduleName] = metadata;
-            _logger.fine('Loaded debug metadata for module: $moduleName');
+            logger.fine('Loaded debug metadata for module: $moduleName');
           } catch (e) {
-            _logger.warning('Failed to read metadata: $e');
-            rethrow;
+            logger.warning('Failed to parse metadata: $e');
           }
         }
       }
@@ -274,18 +273,19 @@ class MetadataProvider {
 
     final moduleLibraries = <String>{};
     for (final library in metadata.libraries.values) {
-      if (library.importUri.startsWith('file:/')) {
-        throw AbsoluteImportUriException(library.importUri);
+      final importUri = library.importUri;
+      if (importUri.startsWith('file:/')) {
+        throw AbsoluteImportUriException(importUri);
       }
-      moduleLibraries.add(library.importUri);
-      _libraries.add(library.importUri);
-      _scripts[library.importUri] = [];
+      moduleLibraries.add(importUri);
+      _libraries.add(importUri);
+      _scripts[importUri] = [];
 
-      _scriptToModule[library.importUri] = moduleName;
+      _scriptToModule[importUri] = moduleName;
       for (final path in library.partUris) {
         // Parts in metadata are relative to the library Uri directory.
-        final partPath = p.url.join(p.dirname(library.importUri), path);
-        _scripts[library.importUri]!.add(partPath);
+        final partPath = p.url.join(p.url.dirname(importUri), path);
+        _scripts[importUri]!.add(partPath);
         _scriptToModule[partPath] = moduleName;
       }
     }