Working compiler in browser.

web/main.dart

 #!/usr/bin/env dart
 // Copyright (c) 2016, 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.
 
 /// Command line entry point for Dart Development Compiler (dartdevc).
 ///
 /// Supported commands are
 ///   * compile: builds a collection of dart libraries into a single JS module
 ///
@@ skipping 17 matching lines @@
 /// * We do not assume a `node` JS installation, so we cannot easily reuse
 ///   existing tools for the "link" step, or assume users have a local
 ///   file server,
 /// * We didn't have a file watcher API at first,
 /// * We had no conventions about where compiled output should go (or even
 ///   that we would be compiling at all, vs running on an in-browser Dart VM),
 /// * We wanted a good first impression with our simple examples, so we used
 ///   local file servers, and users have an expectation of it now, even though
 ///   it doesn't scale to typical apps that need their own real servers.
 
+@JS()
+library dev_compiler.web.main;
+
 import 'dart:async';
-import 'dart:io';
-import 'package:analyzer/src/generated/engine.dart' show AnalysisEngine;
+
 import 'package:args/command_runner.dart';
-import 'package:bazel_worker/bazel_worker.dart';
-import 'package:dev_compiler/src/compiler/command.dart';
+import 'package:js/js.dart';
 
-Future main(List<String> args) async {
-  // Always returns a new modifiable list.
-  args = _preprocessArgs(args);
+import 'web_command.dart';
 
-  if (args.contains('--persistent_worker')) {
-    new _CompilerWorker(args..remove('--persistent_worker')).run();
-  } else {
-    exitCode = await _runCommand(args);
-  }
+@JS()
+external set compileDartExpression(Function function);
+
+Future main() async {
+  var args = ['compile'];
+  _runCommand((result) {
+    compileDartExpression = allowInterop(result);
+  }, args);
 }
 
 /// Runs a single compile command, and returns an exit code.
-Future<int> _runCommand(List<String> args,
+Future<int> _runCommand(Function onload, List<String> args,
     {MessageHandler messageHandler}) async {
   try {
-    if (args.isEmpty || args.first != 'compile' && args.first != 'help') {
-      // TODO(jmesserly): we should deprecate the commands. For now they are
-      // still supported for backwards compatibility.
-      args.insert(0, 'compile');
-    }
     var runner = new CommandRunner('dartdevc', 'Dart Development Compiler');
-    runner.addCommand(new CompileCommand(messageHandler: messageHandler));
+    runner
+        .addCommand(new CompileCommand(onload, messageHandler: messageHandler));
     await runner.run(args);
   } catch (e, s) {
     return _handleError(e, s, args, messageHandler: messageHandler);
   }
-  return EXIT_CODE_OK;
-}
-
-/// Runs the compiler worker loop.
-class _CompilerWorker extends AsyncWorkerLoop {
-  /// The original args supplied to the executable.
-  final List<String> _startupArgs;
-
-  _CompilerWorker(this._startupArgs) : super();
-
-  /// Performs each individual work request.
-  Future<WorkResponse> performRequest(WorkRequest request) async {
-    var args = _startupArgs.toList()..addAll(request.arguments);
-
-    var output = new StringBuffer();
-    var exitCode = await _runCommand(args, messageHandler: output.writeln);
-    AnalysisEngine.instance.clearCaches();
-    return new WorkResponse()
-      ..exitCode = exitCode
-      ..output = output.toString();
-  }
+  return 1;
 }
 
 /// Handles [error] in a uniform fashion. Returns the proper exit code and calls
 /// [messageHandler] with messages.
 int _handleError(dynamic error, dynamic stackTrace, List<String> args,
     {MessageHandler messageHandler}) {
   messageHandler ??= print;
 
   if (error is UsageException) {
     // Incorrect usage, input file not found, etc.
@@ skipping 14 matching lines @@
     messageHandler("We're sorry, you've found a bug in our compiler.");
     messageHandler("You can report this bug at:");
     messageHandler("    https://github.com/dart-lang/dev_compiler/issues");
     messageHandler("");
     messageHandler(
         "Please include the information below in your report, along with");
     messageHandler(
         "any other information that may help us track it down. Thanks!");
     messageHandler("");
     messageHandler("    dartdevc arguments: " + args.join(' '));
-    messageHandler("    dart --version: ${Platform.version}");
     messageHandler("");
     messageHandler("```");
     messageHandler(error);
     messageHandler(stackTrace);
     messageHandler("```");
     return 70;
   }
 }
-
-/// Always returns a new modifiable list.
-///
-/// If the final arg is `@file_path` then read in all the lines of that file
-/// and add those as args.
-///
-/// Bazel actions that support workers must provide all their per-WorkRequest
-/// arguments in a file like this instead of as normal args.
-List<String> _preprocessArgs(List<String> args) {
-  args = new List.from(args);
-  if (args.isNotEmpty && args.last.startsWith('@')) {
-    var fileArg = args.removeLast();
-    args.addAll(new File(fileArg.substring(1)).readAsLinesSync());
-  }
-  return args;
-}