More steps toward making server strong mode clean

pkg/analysis_server/lib/src/analysis_manager.dart

 // Copyright (c) 2014, 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:async';
 import 'dart:convert';
 import 'dart:io';
 
 import 'package:analysis_server/plugin/protocol/protocol.dart';
 import 'package:analysis_server/src/channel/channel.dart';
@@ skipping 18 matching lines @@
    */
   ClientCommunicationChannel channel;
 
   /**
    * Stop the analysis server.
    *
    * Returns `true` if the signal is successfully sent and process terminates.
    * Otherwise there was no attached process or the signal could not be sent,
    * usually meaning that the process is already dead.
    */
-  Future<bool> stop() {
+  Future<bool> stop() async {
     if (process == null) {
-      return channel.close().then((_) => false);
+      await channel.close();
+      return false;
     }
-    return channel
+    int result = await channel
         .sendRequest(new ServerShutdownParams().toRequest('0'))
         .timeout(new Duration(seconds: 2), onTimeout: () {
       print('Expected shutdown response');
     }).then((Response response) {
       return channel.close().then((_) => process.exitCode);
     }).timeout(new Duration(seconds: 2), onTimeout: () {
       print('Expected server to shutdown');
       process.kill();
-    }).then((int result) {
-      if (result != null && result != 0) {
-        exitCode = result;
-      }
-      return true;
     });
+    if (result != null && result != 0) {
+      exitCode = result;
+    }
+    return true;
   }
 
   /**
    * Launch an analysis server and open a connection to that server.
    */
   Future<AnalysisManager> _launchServer(String pathToServer) async {
     try {
       // TODO dynamically allocate port and/or allow client to specify port
       List<String> serverArgs = [pathToServer, '--port', PORT.toString()];
       Process process = await Process.start(Platform.executable, serverArgs);
@@ skipping 27 matching lines @@
     } catch (error) {
       exitCode = 1;
       process.kill();
       throw 'Expected port from analysis server';
     }
   }
 
   /**
    * Open a connection to the analysis server using the given URL.
    */
-  Future<AnalysisManager> _openConnection(String serverUrl) {
+  Future<AnalysisManager> _openConnection(String serverUrl) async {
     Function onError = (error) {
       exitCode = 1;
       if (process != null) {
         process.kill();
       }
       throw 'Failed to connect to analysis server at $serverUrl\n  $error';
     };
     try {
-      return WebSocket
-          .connect(serverUrl)
-          .catchError(onError)
-          .then((WebSocket socket) {
-        this.channel = new WebSocketClientChannel(socket);
-        return this;
-      });
+      WebSocket socket = await WebSocket.connect(serverUrl).catchError(onError);
+      this.channel = new WebSocketClientChannel(socket);
+      return this;
     } catch (error) {
       onError(error);
     }
   }
 
   /**
    * Open a connection to a running analysis server
    * and return a future with a manager for that analysis server.
    */
   static Future<AnalysisManager> connect(String serverUrl) {
     return new AnalysisManager()._openConnection(serverUrl);
   }
 
   /**
    * Launch analysis server in a separate process
    * and return a future with a manager for that analysis server.
    */
   static Future<AnalysisManager> start(String serverPath) {
     return new AnalysisManager()._launchServer(serverPath);
   }
 }