gracefully handle internal exceptions during request

pkg/analysis_server/lib/src/analysis_server.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.
 
 library analysis.server;
 
 import 'dart:async';
 import 'dart:collection';
 
 import 'package:analyzer/file_system/file_system.dart';
@@ skipping 371 matching lines @@
 //        priorityFiles.add(source.fullName);
 //      });
 //    });
 //    return priorityFiles;
 //  }
 
   /**
    * Handle a [request] that was read from the communication channel.
    */
   void handleRequest(Request request) {
-    int count = handlers.length;
-    for (int i = 0; i < count; i++) {
-      try {
-        Response response = handlers[i].handleRequest(request);
-        if (response == Response.DELAYED_RESPONSE) {
+    runZoned(() {
+      int count = handlers.length;
+      for (int i = 0; i < count; i++) {
+        try {
+          Response response = handlers[i].handleRequest(request);
+          if (response == Response.DELAYED_RESPONSE) {
+            return;
+          }
+          if (response != null) {
+            channel.sendResponse(response);
+            return;
+          }
+        } on RequestFailure catch (exception) {
+          channel.sendResponse(exception.response);
           return;
-        }
-        if (response != null) {
+        } catch (exception, stackTrace) {
+          _sendServerErrorNotification(exception, stackTrace);
+          RequestError error =
+              new RequestError(RequestErrorCode.SERVER_ERROR, 'Server Error');
+          Response response = new Response(request.id, error: error);
           channel.sendResponse(response);
           return;
         }
-      } on RequestFailure catch (exception) {
-        channel.sendResponse(exception.response);
-        return;
       }
-    }
-    channel.sendResponse(new Response.unknownRequest(request));
+      channel.sendResponse(new Response.unknownRequest(request));
+    }, onError: _sendServerErrorNotification);
   }
 
   /**
    * Returns `true` if there is a subscription for the given [server] and [file].
    */
   bool hasAnalysisSubscription(AnalysisService service, String file) {
     Set<String> files = analysisServices[service];
     return files != null && files.contains(file);
   }
 
@@ skipping 507 matching lines @@
  * An object that is listening for lifecycle events from an analysis server.
  */
 abstract class AnalysisServerListener {
   /**
    * Analysis is complete.
    */
   void analysisComplete();
 }
 
 typedef void OptionUpdater(AnalysisOptionsImpl options);