flutter_tool: add and use WebCompilerConfig (#124183)

flutter_tool: add and use WebCompilerConfig

Author: kevmoo

packages/flutter_tools/lib/src/build_system/targets/web.dart

@@ -34,37 +34,12 @@ import 'shader_compiler.dart';
 /// Whether the application has web plugins.
 const String kHasWebPlugins = 'HasWebPlugins';
 
-/// An override for the dart2js build mode.
-///
-/// Valid values are O1 (lowest, profile default) to O4 (highest, release default).
-const String kDart2jsOptimization = 'Dart2jsOptimization';
-
-/// The default optimization level for dart2js.
-///
-/// Maps to [kDart2jsOptimization].
-const String kDart2jsDefaultOptimizationLevel = 'O4';
-
-/// If `--dump-info` should be passed to dart2js.
-const String kDart2jsDumpInfo = 'Dart2jsDumpInfo';
-
-// If `--no-frequency-based-minification` should be based to dart2js
-const String kDart2jsNoFrequencyBasedMinification = 'Dart2jsNoFrequencyBasedMinification';
-
-/// Whether to disable dynamic generation code to satisfy csp policies.
-const String kCspMode = 'cspMode';
-
 /// Base href to set in index.html in flutter build command
 const String kBaseHref = 'baseHref';
 
 /// The caching strategy to use for service worker generation.
 const String kServiceWorkerStrategy = 'ServiceWorkerStrategy';
 
-/// Whether the dart2js build should output source maps.
-const String kSourceMapsEnabled = 'SourceMaps';
-
-/// Whether the dart2js native null assertions are enabled.
-const String kNativeNullAssertions = 'NativeNullAssertions';
-
 const String kOfflineFirst = 'offline-first';
 const String kNoneWorker = 'none';
 
@@ -201,8 +176,7 @@ class Dart2JSTarget extends Dart2WebTarget {
       throw MissingDefineException(kBuildMode, name);
     }
     final BuildMode buildMode = getBuildModeForName(buildModeEnvironment);
-    final bool sourceMapsEnabled = environment.defines[kSourceMapsEnabled] == 'true';
-    final bool nativeNullAssertions = environment.defines[kNativeNullAssertions] == 'true';
+    final JsCompilerConfig compilerConfig = JsCompilerConfig.fromBuildSystemEnvironment(environment.defines);
     final Artifacts artifacts = globals.artifacts!;
     final String platformBinariesPath = getWebPlatformBinariesDirectory(artifacts, webRenderer).path;
     final List<String> sharedCommandOptions = <String>[
@@ -212,20 +186,17 @@ class Dart2JSTarget extends Dart2WebTarget {
       '--platform-binaries=$platformBinariesPath',
       ...decodeCommaSeparated(environment.defines, kExtraFrontEndOptions),
       '--invoker=flutter_tool',
-      if (nativeNullAssertions)
-        '--native-null-assertions',
       if (buildMode == BuildMode.profile)
         '-Ddart.vm.profile=true'
       else
         '-Ddart.vm.product=true',
       for (final String dartDefine in decodeDartDefines(environment.defines, kDartDefines))
         '-D$dartDefine',
-      if (!sourceMapsEnabled)
-        '--no-source-maps',
     ];
 
     final List<String> compilationArgs = <String>[
       ...sharedCommandOptions,
+      ...compilerConfig.toSharedCommandOptions(),
       '-o',
       environment.buildDir.childFile('app.dill').path,
       '--packages=.dart_tool/package_config.json',
@@ -241,19 +212,12 @@ class Dart2JSTarget extends Dart2WebTarget {
       throw Exception(_collectOutput(kernelResult));
     }
 
-    final String dart2jsOptimization = environment.defines[kDart2jsOptimization] ?? kDart2jsDefaultOptimizationLevel;
-    final bool dumpInfo = environment.defines[kDart2jsDumpInfo] == 'true';
-    final bool noFrequencyBasedMinification = environment.defines[kDart2jsNoFrequencyBasedMinification] == 'true';
     final File outputJSFile = environment.buildDir.childFile('main.dart.js');
-    final bool csp = environment.defines[kCspMode] == 'true';
 
     final ProcessResult javaScriptResult = await environment.processManager.run(<String>[
       ...sharedCommandOptions,
-      '-$dart2jsOptimization',
       if (buildMode == BuildMode.profile) '--no-minify',
-      if (dumpInfo) '--dump-info',
-      if (noFrequencyBasedMinification) '--no-frequency-based-minification',
-      if (csp) '--csp',
+      ...compilerConfig.toCommandOptions(),
       '-o',
       outputJSFile.path,
       environment.buildDir.childFile('app.dill').path, // dartfile

packages/flutter_tools/lib/src/commands/build_web.dart

@@ -81,7 +81,7 @@ class BuildWebCommand extends BuildSubCommand {
     argParser.addOption('dart2js-optimization',
       help: 'Sets the optimization level used for Dart compilation to JavaScript. '
           'Valid values range from O0 to O4.',
-          defaultsTo: kDart2jsDefaultOptimizationLevel
+          defaultsTo: JsCompilerConfig.kDart2jsDefaultOptimizationLevel
     );
     argParser.addFlag('dump-info', negatable: false,
       help: 'Passes "--dump-info" to the Javascript compiler which generates '
@@ -134,9 +134,21 @@ class BuildWebCommand extends BuildSubCommand {
       throwToolExit('"build web" is not currently supported. To enable, run "flutter config --enable-web".');
     }
 
-    final bool wasmRequested = boolArg(FlutterOptions.kWebWasmFlag);
-    if (wasmRequested && !featureFlags.isFlutterWebWasmEnabled) {
-      throwToolExit('Compiling to WebAssembly (wasm) is only available on the master channel.');
+    final WebCompilerConfig compilerConfig;
+    if (boolArg('wasm')) {
+      if (!featureFlags.isFlutterWebWasmEnabled) {
+        throwToolExit('Compiling to WebAssembly (wasm) is only available on the master channel.');
+      }
+      compilerConfig = const WasmCompilerConfig();
+    } else {
+      compilerConfig = JsCompilerConfig(
+        csp: boolArg('csp'),
+        optimizationLevel: stringArg('dart2js-optimization') ?? JsCompilerConfig.kDart2jsDefaultOptimizationLevel,
+        dumpInfo: boolArg('dump-info'),
+        nativeNullAssertions: boolArg('native-null-assertions'),
+        noFrequencyBasedMinification: boolArg('no-frequency-based-minification'),
+        sourceMaps: boolArg('source-maps'),
+      );
     }
 
     final FlutterProject flutterProject = FlutterProject.current();
@@ -180,16 +192,10 @@ class BuildWebCommand extends BuildSubCommand {
       flutterProject,
       target,
       buildInfo,
-      boolArg('csp'),
       stringArg('pwa-strategy')!,
-      boolArg('source-maps'),
-      boolArg('native-null-assertions'),
-      wasmRequested,
+      compilerConfig: compilerConfig,
       baseHref: baseHref,
-      dart2jsOptimization: stringArg('dart2js-optimization') ?? kDart2jsDefaultOptimizationLevel,
       outputDirectoryPath: outputDirectoryPath,
-      dumpInfo: boolArg('dump-info'),
-      noFrequencyBasedMinification: boolArg('no-frequency-based-minification'),
     );
     return FlutterCommandResult.success();
   }

packages/flutter_tools/lib/src/isolated/resident_web_runner.dart

@@ -325,11 +325,8 @@ Please provide a valid TCP port (an integer between 0 and 65535, inclusive).
             flutterProject,
             target,
             debuggingOptions.buildInfo,
-            false,
             kNoneWorker,
-            true,
-            debuggingOptions.nativeNullAssertions,
-            false,
+            compilerConfig: JsCompilerConfig.run(nativeNullAssertions: debuggingOptions.nativeNullAssertions)
           );
         }
         await device!.device!.startApp(
@@ -405,11 +402,8 @@ Please provide a valid TCP port (an integer between 0 and 65535, inclusive).
           flutterProject,
           target,
           debuggingOptions.buildInfo,
-          false,
           kNoneWorker,
-          true,
-          debuggingOptions.nativeNullAssertions,
-          false,
+          compilerConfig: JsCompilerConfig.run(nativeNullAssertions: debuggingOptions.nativeNullAssertions),
         );
       } on ToolExit {
         return OperationResult(1, 'Failed to recompile application.');

packages/flutter_tools/lib/src/web/compile.dart

@@ -18,9 +18,10 @@ import '../plugins.dart';
 import '../project.dart';
 import '../reporting/reporting.dart';
 import '../version.dart';
+import 'compiler_config.dart';
 import 'migrations/scrub_generated_plugin_registrant.dart';
 
-export '../build_system/targets/web.dart' show kDart2jsDefaultOptimizationLevel;
+export 'compiler_config.dart';
 
 class WebBuilder {
   WebBuilder({
@@ -45,18 +46,12 @@ class WebBuilder {
     FlutterProject flutterProject,
     String target,
     BuildInfo buildInfo,
-    bool csp,
-    String serviceWorkerStrategy,
-    bool sourceMaps,
-    bool nativeNullAssertions,
-    bool isWasm, {
-    String dart2jsOptimization = kDart2jsDefaultOptimizationLevel,
+    String serviceWorkerStrategy, {
+    required WebCompilerConfig compilerConfig,
     String? baseHref,
-    bool dumpInfo = false,
-    bool noFrequencyBasedMinification = false,
     String? outputDirectoryPath,
   }) async {
-    if (isWasm) {
+    if (compilerConfig.isWasm) {
       globals.logger.printBox(
         title: 'Experimental feature',
         '''
@@ -68,7 +63,7 @@ class WebBuilder {
     final bool hasWebPlugins =
         (await findPlugins(flutterProject)).any((Plugin p) => p.platforms.containsKey(WebPlugin.kConfigKey));
     final Directory outputDirectory = outputDirectoryPath == null
-        ? _fileSystem.directory(getWebBuildDirectory(isWasm))
+        ? _fileSystem.directory(getWebBuildDirectory(compilerConfig.isWasm))
         : _fileSystem.directory(outputDirectoryPath);
     outputDirectory.createSync(recursive: true);
 
@@ -84,22 +79,17 @@ class WebBuilder {
     final Stopwatch sw = Stopwatch()..start();
     try {
       final BuildResult result = await _buildSystem.build(
-          WebServiceWorker(_fileSystem, buildInfo.webRenderer, isWasm: isWasm),
+          WebServiceWorker(_fileSystem, buildInfo.webRenderer, isWasm: compilerConfig.isWasm),
           Environment(
             projectDir: _fileSystem.currentDirectory,
             outputDir: outputDirectory,
             buildDir: flutterProject.directory.childDirectory('.dart_tool').childDirectory('flutter_build'),
             defines: <String, String>{
               kTargetFile: target,
               kHasWebPlugins: hasWebPlugins.toString(),
-              kCspMode: csp.toString(),
               if (baseHref != null) kBaseHref: baseHref,
-              kSourceMapsEnabled: sourceMaps.toString(),
-              kNativeNullAssertions: nativeNullAssertions.toString(),
               kServiceWorkerStrategy: serviceWorkerStrategy,
-              kDart2jsOptimization: dart2jsOptimization,
-              kDart2jsDumpInfo: dumpInfo.toString(),
-              kDart2jsNoFrequencyBasedMinification: noFrequencyBasedMinification.toString(),
+              ...compilerConfig.toBuildSystemEnvironment(),
               ...buildInfo.toBuildSystemEnvironment(),
             },
             artifacts: globals.artifacts!,

packages/flutter_tools/lib/src/web/compiler_config.dart

@@ -0,0 +1,138 @@
+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+abstract class WebCompilerConfig {
+  const WebCompilerConfig();
+
+  /// Returns `true` if `this` represents configuration for the Wasm compiler.
+  ///
+  /// Otherwise, `false`–represents the JavaScript compiler.
+  bool get isWasm;
+
+  Map<String, String> toBuildSystemEnvironment();
+}
+
+/// Configuration for the Dart-to-Javascript compiler (dart2js).
+class JsCompilerConfig extends WebCompilerConfig {
+  const JsCompilerConfig({
+    required this.csp,
+    required this.dumpInfo,
+    required this.nativeNullAssertions,
+    required this.optimizationLevel,
+    required this.noFrequencyBasedMinification,
+    required this.sourceMaps,
+  });
+
+  /// Instantiates [JsCompilerConfig] suitable for the `flutter run` command.
+  const JsCompilerConfig.run({required bool nativeNullAssertions})
+      : this(
+          csp: false,
+          dumpInfo: false,
+          nativeNullAssertions: nativeNullAssertions,
+          noFrequencyBasedMinification: false,
+          optimizationLevel: kDart2jsDefaultOptimizationLevel,
+          sourceMaps: true,
+        );
+
+  /// Creates a new [JsCompilerConfig] from build system environment values.
+  ///
+  /// Should correspond exactly with [toBuildSystemEnvironment].
+  factory JsCompilerConfig.fromBuildSystemEnvironment(
+          Map<String, String> defines) =>
+      JsCompilerConfig(
+        csp: defines[kCspMode] == 'true',
+        dumpInfo: defines[kDart2jsDumpInfo] == 'true',
+        nativeNullAssertions: defines[kNativeNullAssertions] == 'true',
+        optimizationLevel: defines[kDart2jsOptimization] ?? kDart2jsDefaultOptimizationLevel,
+        noFrequencyBasedMinification: defines[kDart2jsNoFrequencyBasedMinification] == 'true',
+        sourceMaps: defines[kSourceMapsEnabled] == 'true',
+      );
+
+  /// The default optimization level for dart2js.
+  ///
+  /// Maps to [kDart2jsOptimization].
+  static const String kDart2jsDefaultOptimizationLevel = 'O4';
+
+  /// Build environment flag for [optimizationLevel].
+  static const String kDart2jsOptimization = 'Dart2jsOptimization';
+
+  /// Build environment flag for [dumpInfo].
+  static const String kDart2jsDumpInfo = 'Dart2jsDumpInfo';
+
+  /// Build environment flag for [noFrequencyBasedMinification].
+  static const String kDart2jsNoFrequencyBasedMinification =
+      'Dart2jsNoFrequencyBasedMinification';
+
+  /// Build environment flag for [csp].
+  static const String kCspMode = 'cspMode';
+
+  /// Build environment flag for [sourceMaps].
+  static const String kSourceMapsEnabled = 'SourceMaps';
+
+  /// Build environment flag for [nativeNullAssertions].
+  static const String kNativeNullAssertions = 'NativeNullAssertions';
+
+  /// Whether to disable dynamic generation code to satisfy CSP policies.
+  final bool csp;
+
+  /// If `--dump-info` should be passed to the compiler.
+  final bool dumpInfo;
+
+  /// Whether native null assertions are enabled.
+  final bool nativeNullAssertions;
+
+  // If `--no-frequency-based-minification` should be passed to dart2js
+  // TODO(kevmoo): consider renaming this to be "positive". Double negatives are confusing.
+  final bool noFrequencyBasedMinification;
+
+  /// The compiler optimization level.
+  ///
+  /// Valid values are O1 (lowest, profile default) to O4 (highest, release default).
+  // TODO(kevmoo): consider storing this as an [int] and validating it!
+  final String optimizationLevel;
+
+  /// `true` if the JavaScript compiler build should output source maps.
+  final bool sourceMaps;
+
+  @override
+  bool get isWasm => false;
+
+  @override
+  Map<String, String> toBuildSystemEnvironment() => <String, String>{
+        kCspMode: csp.toString(),
+        kDart2jsDumpInfo: dumpInfo.toString(),
+        kNativeNullAssertions: nativeNullAssertions.toString(),
+        kDart2jsNoFrequencyBasedMinification: noFrequencyBasedMinification.toString(),
+        kDart2jsOptimization: optimizationLevel,
+        kSourceMapsEnabled: sourceMaps.toString(),
+      };
+
+  /// Arguments to use in both phases: full JS compile and CFE-only.
+  List<String> toSharedCommandOptions() => <String>[
+        if (nativeNullAssertions) '--native-null-assertions',
+        if (!sourceMaps) '--no-source-maps',
+      ];
+
+  /// Arguments to use in the full JS compile, but not CFE-only.
+  ///
+  /// Includes the contents of [toSharedCommandOptions].
+  List<String> toCommandOptions() => <String>[
+        ...toSharedCommandOptions(),
+        '-$optimizationLevel',
+        if (dumpInfo) '--dump-info',
+        if (noFrequencyBasedMinification) '--no-frequency-based-minification',
+        if (csp) '--csp',
+      ];
+}
+
+/// Configuration for the Wasm compiler.
+class WasmCompilerConfig extends WebCompilerConfig {
+  const WasmCompilerConfig();
+
+  @override
+  bool get isWasm => true;
+
+  @override
+  Map<String, String> toBuildSystemEnvironment() => const <String, String>{};
+}