SIGQUIT toggles VM service HTTP server

runtime/bin/vmservice/vmservice_io.dart

 // 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 vmservice_io;
 
 import 'dart:async';
 import 'dart:convert';
 import 'dart:io';
 import 'dart:isolate';
 import 'dart:vmservice';
 
 part 'resources.dart';
 part 'server.dart';
 
 // The TCP port that the HTTP server listens on.
 int _port;
 
+// HTTP servr.
+Server server;
+
 // The VM service instance.
 VMService service;
 
+void _onSignal(ProcessSignal signal) {

[Ivan Posva, 2014/04/14 16:12:58]

_onUSR1Signal or _onVMServiceSignal

[Cutch, 2014/04/15 17:42:07]

Done.

+  // Toggle HTTP server.
+  if (server.running) {
+    server.shutdown();
+  } else {
+    server.startup();
+  }
+}
+
 main() {
   // Get VMService.
   service = new VMService();
+  // Listen for SIGUSR1.
+  ProcessSignal.SIGUSR1.watch().listen(_onSignal);

[turnidge, 2014/04/14 16:51:46]

If a signal is processed immediately at this point, could the server be started
twice?

Does it make sense to move the listen() call to after the end of this function,
after the server has started?

[Cutch, 2014/04/15 17:42:07]

dart:io signals aren't delivered like regular signals are delivered, signals
received by the process are queued up and shared across isolates. But, I've
moved the signal listening code to be after the startup. I've also modified the
server to ignore startup/shutdown requests while transitioning between the
shutdown and startup states.

   // Start HTTP server.
-  var server = new Server(service, _port);
-  server.startServer();
+  server = new Server(service, _port);
+  if (_port != 0) {
+    // Port was specified, start HTTP server immediately.
+    server.startup();
+  }
 }