Migrate frontend-server-common to null safety (#1650)

* Remove dead code

* Remove abstract ResidentCompiler class

* Migrate events and utilities to null safety

* Migrate some of dwds files to null safety

* Migrate frontend_server_common to null safety

* Fixed bad merge

* Fixed analyzer warning

* Address CR comments

* Addressed CR comments

* Format

* Address CR comments

* Address CR comments, make fields of StdoutHandler private

Author: Anna Gringauze

frontend_server_common/CHANGELOG.md

@@ -1,3 +1,6 @@
+## 0.2.0
+- Migrate to null safety
+
 ## 0.1.1
 - Remove dead code
 

frontend_server_common/lib/src/asset_server.dart

@@ -2,16 +2,14 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.9
-
 // Note: this is a copy from flutter tools, updated to work with dwds tests
 
 import 'dart:async';
 import 'dart:convert';
 import 'dart:io';
 import 'dart:typed_data';
 
-import 'package:dwds/dwds.dart';
+import 'package:dwds/asset_reader.dart';
 import 'package:file/file.dart';
 import 'package:logging/logging.dart';
 import 'package:mime/mime.dart' as mime;
@@ -32,10 +30,10 @@ class TestAssetServer implements AssetReader {
   static const String _defaultMimeType = 'application/octet-stream';
   final FileSystem _fileSystem;
   final HttpServer _httpServer;
-  final Map<String, Uint8List> _files = <String, Uint8List>{};
-  final Map<String, Uint8List> _sourcemaps = <String, Uint8List>{};
-  final Map<String, Uint8List> _metadata = <String, Uint8List>{};
-  String _mergedMetadata;
+  final Map<String, Uint8List> _files = {};
+  final Map<String, Uint8List> _sourceMaps = {};
+  final Map<String, Uint8List> _metadata = {};
+  late String _mergedMetadata;
   final PackageConfig _packageConfig;
   final InternetAddress internetAddress;
 
@@ -47,6 +45,15 @@ class TestAssetServer implements AssetReader {
     this._fileSystem,
   ) : basePath = _parseBasePathFromIndexHtml(index);
 
+  bool hasFile(String path) => _files.containsKey(path);
+  Uint8List getFile(String path) => _files[path]!;
+
+  bool hasSourceMap(String path) => _sourceMaps.containsKey(path);
+  Uint8List getSourceMap(String path) => _sourceMaps[path]!;
+
+  bool hasMetadata(String path) => _metadata.containsKey(path);
+  Uint8List getMetadata(String path) => _metadata[path]!;
+
   /// Start the web asset server on a [hostname] and [port].
   ///
   /// Unhandled exceptions will throw a exception with the error and stack
@@ -66,10 +73,6 @@ class TestAssetServer implements AssetReader {
     return server;
   }
 
-  Uint8List getFile(String path) => _files[path];
-
-  Uint8List getSourceMap(String path) => _sourcemaps[path];
-
   // handle requests for JavaScript source, dart sources maps, or asset files.
   Future<shelf.Response> handleRequest(shelf.Request request) async {
     var headers = <String, String>{};
@@ -94,21 +97,18 @@ class TestAssetServer implements AssetReader {
       requestPath = _stripBasePath(requestPath, basePath) ?? requestPath;
 
       requestPath = requestPath.startsWith('/') ? requestPath : '/$requestPath';
-      if (requestPath == null) {
-        return shelf.Response.notFound('');
-      }
 
       // If this is a JavaScript file, it must be in the in-memory cache.
       // Attempt to look up the file by URI.
-      if (_files.containsKey(requestPath)) {
+      if (hasFile(requestPath)) {
         final List<int> bytes = getFile(requestPath);
         headers[HttpHeaders.contentLengthHeader] = bytes.length.toString();
         headers[HttpHeaders.contentTypeHeader] = 'application/javascript';
         return shelf.Response.ok(bytes, headers: headers);
       }
       // If this is a sourcemap file, then it might be in the in-memory cache.
       // Attempt to lookup the file by URI.
-      if (_sourcemaps.containsKey(requestPath)) {
+      if (hasSourceMap(requestPath)) {
         final List<int> bytes = getSourceMap(requestPath);
         headers[HttpHeaders.contentLengthHeader] = bytes.length.toString();
         headers[HttpHeaders.contentTypeHeader] = 'application/json';
@@ -124,7 +124,7 @@ class TestAssetServer implements AssetReader {
     // Attempt to determine the file's mime type. if this is not provided some
     // browsers will refuse to render images/show video et cetera. If the tool
     // cannot determine a mime type, fall back to application/octet-stream.
-    String mimeType;
+    String? mimeType;
     if (length >= 12) {
       mimeType = mime.lookupMimeType(
         file.path,
@@ -160,10 +160,6 @@ class TestAssetServer implements AssetReader {
     var manifest =
         _castStringKeyedMap(json.decode(manifestFile.readAsStringSync()));
     for (var filePath in manifest.keys) {
-      if (filePath == null) {
-        _logger.severe('Invalid manfiest file: $filePath');
-        continue;
-      }
       var offsets = _castStringKeyedMap(manifest[filePath]);
       var codeOffsets = (offsets['code'] as List<dynamic>).cast<int>();
       var sourcemapOffsets =
@@ -200,7 +196,7 @@ class TestAssetServer implements AssetReader {
         sourcemapStart,
         sourcemapEnd - sourcemapStart,
       );
-      _sourcemaps['$filePath.map'] = sourcemapView;
+      _sourceMaps['$filePath.map'] = sourcemapView;
 
       var metadataStart = metadataOffsets[0];
       var metadataEnd = metadataOffsets[1];
@@ -259,36 +255,42 @@ class TestAssetServer implements AssetReader {
   }
 
   @override
-  Future<String> dartSourceContents(String serverPath) {
-    serverPath = _stripBasePath(serverPath, basePath);
-    var result = _resolveDartFile(serverPath);
-    if (result.existsSync()) {
-      return result.readAsString();
+  Future<String?> dartSourceContents(String serverPath) async {
+    final stripped = _stripBasePath(serverPath, basePath);
+    if (stripped != null) {
+      var result = _resolveDartFile(stripped);
+      if (result.existsSync()) {
+        return result.readAsString();
+      }
     }
     _logger.severe('Source not found: $serverPath');
     return null;
   }
 
   @override
-  Future<String> sourceMapContents(String serverPath) async {
-    serverPath = _stripBasePath(serverPath, basePath);
-    var path = '/$serverPath';
-    if (_sourcemaps.containsKey(path)) {
-      return utf8.decode(_sourcemaps[path]);
+  Future<String?> sourceMapContents(String serverPath) async {
+    final stripped = _stripBasePath(serverPath, basePath);
+    if (stripped != null) {
+      var path = '/$stripped';
+      if (hasSourceMap(path)) {
+        return utf8.decode(getSourceMap(path));
+      }
     }
     _logger.severe('Source map not found: $serverPath');
     return null;
   }
 
   @override
-  Future<String> metadataContents(String serverPath) async {
-    serverPath = _stripBasePath(serverPath, basePath);
-    if (serverPath.endsWith('.ddc_merged_metadata')) {
-      return _mergedMetadata;
-    }
-    var path = '/$serverPath';
-    if (_metadata.containsKey(path)) {
-      return utf8.decode(_metadata[path]);
+  Future<String?> metadataContents(String serverPath) async {
+    final stripped = _stripBasePath(serverPath, basePath);
+    if (stripped != null) {
+      if (stripped.endsWith('.ddc_merged_metadata')) {
+        return _mergedMetadata;
+      }
+      var path = '/$stripped';
+      if (hasMetadata(path)) {
+        return utf8.decode(getMetadata(path));
+      }
     }
     _logger.severe('Metadata not found: $serverPath');
     return null;
@@ -299,7 +301,7 @@ class TestAssetServer implements AssetReader {
 /// the same structure (`Map<String, dynamic>`) with the correct runtime types.
 Map<String, dynamic> _castStringKeyedMap(dynamic untyped) {
   var map = untyped as Map<dynamic, dynamic>;
-  return map?.cast<String, dynamic>();
+  return map.cast<String, dynamic>();
 }
 
 String _stripLeadingSlashes(String path) {
@@ -309,7 +311,7 @@ String _stripLeadingSlashes(String path) {
   return path;
 }
 
-String _stripBasePath(String path, String basePath) {
+String? _stripBasePath(String path, String basePath) {
   path = _stripLeadingSlashes(path);
   if (path.startsWith(basePath)) {
     path = path.substring(basePath.length);
@@ -327,5 +329,6 @@ String _parseBasePathFromIndexHtml(String index) {
   }
   final contents = file.readAsStringSync();
   final matches = RegExp(r'<base href="/([^>]*)/">').allMatches(contents);
-  return matches.isEmpty ? '' : matches.first.group(1);
+  if (matches.isEmpty) return '';
+  return matches.first.group(1) ?? '';
 }

frontend_server_common/lib/src/bootstrap.dart

@@ -2,12 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.9
-
 // Note: this is a copy from flutter tools, updated to work with dwds tests
 
-import 'package:meta/meta.dart';
-
 /// The JavaScript bootstrap script to support in-browser hot restart.
 ///
 /// The [requireUrl] loads our cached RequireJS script file. The [mapperUrl]
@@ -18,9 +14,9 @@ import 'package:meta/meta.dart';
 /// and is responsible for bootstrapping the RequireJS modules and attaching
 /// the hot reload hooks.
 String generateBootstrapScript({
-  @required String requireUrl,
-  @required String mapperUrl,
-  @required String entrypoint,
+  required String requireUrl,
+  required String mapperUrl,
+  required String entrypoint,
 }) {
   return '''
 "use strict";
@@ -53,7 +49,7 @@ document.head.appendChild(requireEl);
 /// the file `foo/bar/baz.dart` will generate a property named approximately
 /// `foo__bar__baz`. Rather than attempt to guess, we assume the first property of
 /// this object is the module.
-String generateMainModule({@required String entrypoint}) {
+String generateMainModule({required String entrypoint}) {
   return '''/* ENTRYPOINT_EXTENTION_MARKER */
 
 // Create the main module loaded below.

frontend_server_common/lib/src/devfs.dart

@@ -2,15 +2,12 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @dart = 2.9
-
 // Note: this is a copy from flutter tools, updated to work with dwds tests
 
 import 'dart:io';
 
-import 'package:dwds/dwds.dart';
+import 'package:dwds/asset_reader.dart';
 import 'package:file/file.dart';
-import 'package:meta/meta.dart';
 import 'package:package_config/package_config.dart';
 import 'package:path/path.dart' as p;
 
@@ -23,28 +20,27 @@ final String dartWebSdkPath = p.join(dartSdkPath, 'lib', 'dev_compiler');
 
 class WebDevFS {
   WebDevFS({
-    this.fileSystem,
-    this.hostname,
-    this.port,
-    this.projectDirectory,
-    this.packageConfigFile,
-    this.index,
-    this.urlTunneller,
-    this.soundNullSafety,
+    required this.fileSystem,
+    required this.hostname,
+    required this.port,
+    required this.projectDirectory,
+    required this.packageConfigFile,
+    required this.index,
+    required this.urlTunneller,
+    required this.soundNullSafety,
   });
 
   final FileSystem fileSystem;
-  TestAssetServer assetServer;
+  late final TestAssetServer assetServer;
   final String hostname;
   final int port;
   final Uri projectDirectory;
   final Uri packageConfigFile;
   final String index;
   final UrlEncoder urlTunneller;
   final bool soundNullSafety;
-  Directory _savedCurrentDirectory;
-  List<Uri> sources;
-  PackageConfig _packageConfig;
+  late final Directory _savedCurrentDirectory;
+  late final PackageConfig _packageConfig;
 
   Future<Uri> create() async {
     _savedCurrentDirectory = fileSystem.currentDirectory;
@@ -61,16 +57,15 @@ class WebDevFS {
 
   Future<void> dispose() {
     fileSystem.currentDirectory = _savedCurrentDirectory;
-    return assetServer?.close();
+    return assetServer.close();
   }
 
   Future<UpdateFSReport> update({
-    Uri mainUri,
-    String dillOutputPath,
-    @required ResidentCompiler generator,
-    List<Uri> invalidatedFiles,
+    required Uri mainUri,
+    required String dillOutputPath,
+    required ResidentCompiler generator,
+    required List<Uri> invalidatedFiles,
   }) async {
-    assert(generator != null);
     final mainPath = mainUri.toFilePath();
     final outputDirectoryPath = fileSystem.file(mainPath).parent.path;
     final entryPoint = mainUri.toString();
@@ -108,8 +103,6 @@ class WebDevFS {
       return UpdateFSReport(success: false);
     }
 
-    // list of sources that needs to be monitored are in [compilerOutput.sources]
-    sources = compilerOutput.sources;
     File codeFile;
     File manifestFile;
     File sourcemapFile;
@@ -200,7 +193,7 @@ class UpdateFSReport {
   /// mode.
   ///
   /// Only used for JavaScript compilation.
-  List<String> invalidatedModules;
+  List<String>? invalidatedModules;
 }
 
 String _filePathToUriFragment(String path) {