Revert "Revert "Use native async/await support in pub.""

sdk/lib/_internal/pub_generated/lib/src/barback/transformer_isolate.dart

Index: sdk/lib/_internal/pub_generated/lib/src/barback/transformer_isolate.dart
diff --git a/sdk/lib/_internal/pub_generated/lib/src/barback/transformer_isolate.dart b/sdk/lib/_internal/pub_generated/lib/src/barback/transformer_isolate.dart
deleted file mode 100644
index 04298d2be1fb066311f30868801f2e26bb699dcf..0000000000000000000000000000000000000000
--- a/sdk/lib/_internal/pub_generated/lib/src/barback/transformer_isolate.dart
+++ /dev/null
@@ -1,141 +0,0 @@
-// Copyright (c) 2013, 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.
-
-library pub.transformer_isolate;
-
-import 'dart:async';
-import 'dart:convert';
-import 'dart:isolate';
-
-import 'package:barback/barback.dart';
-import 'package:source_span/source_span.dart';
-import 'package:stack_trace/stack_trace.dart';
-
-import '../../../asset/dart/serialize.dart';
-import '../barback.dart';
-import '../exceptions.dart';
-import '../dart.dart' as dart;
-import '../log.dart' as log;
-import '../utils.dart';
-import 'asset_environment.dart';
-import 'barback_server.dart';
-import 'foreign_transformer.dart';
-import 'transformer_config.dart';
-import 'transformer_id.dart';
-
-/// A wrapper for an isolate from which transformer plugins can be instantiated.
-class TransformerIsolate {
-  /// The port used to communicate with the wrapped isolate.
-  final SendPort _port;
-
-  /// A map indicating the barback server URLs for each [TransformerId] that's
-  /// loaded in the wrapped isolate.
-  ///
-  /// A barback server URL is the URL for the library that the given id
-  /// identifies. For example, the URL for "polymer/src/mirrors_remover" might
-  /// be "http://localhost:56234/packages/polymer/src/mirrors_remover.dart".
-  final Map<TransformerId, Uri> _idsToUrls;
-
-  /// The barback mode for this run of pub.
-  final BarbackMode _mode;
-
-  /// Spawns an isolate that loads all transformer libraries defined by [ids].
-  ///
-  /// This doesn't actually instantiate any transformers, since a
-  /// [TransformerId] doesn't define the transformers' configuration. The
-  /// transformers can be constructed using [create].
-  ///
-  /// If [snapshot] is passed, the isolate will be loaded from that path if it
-  /// exists. Otherwise, a snapshot of the isolate's code will be saved to that
-  /// path once the isolate is loaded.
-  static Future<TransformerIsolate> spawn(AssetEnvironment environment,
-      BarbackServer transformerServer, List<TransformerId> ids, {String snapshot}) {
-    return mapFromIterableAsync(ids, value: (id) {
-      return id.getAssetId(environment.barback);
-    }).then((idsToAssetIds) {
-      var baseUrl = transformerServer.url;
-      var idsToUrls = mapMap(idsToAssetIds, value: (id, assetId) {
-        var path = assetId.path.replaceFirst('lib/', '');
-        return Uri.parse('package:${id.package}/$path');
-      });
-
-      var code = new StringBuffer();
-      code.writeln("import 'dart:isolate';");
-
-      for (var url in idsToUrls.values) {
-        code.writeln("import '$url';");
-      }
-
-      code.writeln("import r'package:\$pub/transformer_isolate.dart';");
-      code.writeln(
-          "void main(_, SendPort replyTo) => loadTransformers(replyTo);");
-
-      log.fine("Loading transformers from $ids");
-
-      var port = new ReceivePort();
-      return dart.runInIsolate(
-          code.toString(),
-          port.sendPort,
-          packageRoot: baseUrl.resolve('packages'),
-          snapshot: snapshot).then((_) => port.first).then((sendPort) {
-        return new TransformerIsolate._(sendPort, environment.mode, idsToUrls);
-      }).catchError((error, stackTrace) {
-        if (error is! CrossIsolateException) throw error;
-        if (error.type != 'IsolateSpawnException') throw error;
-
-        // TODO(nweiz): don't parse this as a string once issues 12617 and 12689
-        // are fixed.
-        var firstErrorLine = error.message.split('\n')[1];
-
-        // The isolate error message contains the fully expanded path, not the
-        // "package:" URI, so we have to be liberal in what we look for in the
-        // error message.
-        var missingTransformer = idsToUrls.keys.firstWhere(
-            (id) =>
-                firstErrorLine.startsWith("Uncaught Error: Load Error: Failure getting ") &&
-                    firstErrorLine.contains(idsToUrls[id].path),
-            orElse: () => throw error);
-        var packageUri = idToPackageUri(idsToAssetIds[missingTransformer]);
-
-        // If there was an IsolateSpawnException and the import that actually
-        // failed was the one we were loading transformers from, throw an
-        // application exception with a more user-friendly message.
-        fail('Transformer library "$packageUri" not found.', error, stackTrace);
-      });
-    });
-  }
-
-  TransformerIsolate._(this._port, this._mode, this._idsToUrls);
-
-  /// Instantiate the transformers in the [config.id] with
-  /// [config.configuration].
-  ///
-  /// If there are no transformers defined in the given library, this will
-  /// return an empty set.
-  Future<Set<Transformer>> create(TransformerConfig config) {
-    return call(_port, {
-      'library': _idsToUrls[config.id].toString(),
-      'mode': _mode.name,
-      'configuration': JSON.encode(config.configuration)
-    }).then((transformers) {
-      transformers = transformers.map(
-          (transformer) => deserializeTransformerLike(transformer, config)).toSet();
-      log.fine("Transformers from $config: $transformers");
-      return transformers;
-    }).catchError((error, stackTrace) {
-      throw new TransformerLoadError(error, config.span);
-    });
-  }
-}
-
-/// An error thrown when a transformer fails to load.
-class TransformerLoadError extends SourceSpanException implements
-    WrappedException {
-  final CrossIsolateException innerError;
-  Chain get innerChain => innerError.stackTrace;
-
-  TransformerLoadError(CrossIsolateException error, SourceSpan span)
-      : innerError = error,
-        super("Error loading transformer: ${error.message}", span);
-}