Provide an API to dart:developer to control the web server hosting the Service Protocol

sdk/lib/developer/service.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.
+
+part of dart.developer;
+
+/// Information about the service protocol.
+class ServiceProtocolInfo {
+  /// The major version of the protocol.
+  final int majorVersion = _getServiceMajorVersion();
+  /// The minor version of the protocol.
+  final int minorVersion = _getServiceMinorVersion();
+  /// The Uri to access the service. If the web server is not running, this
+  /// will be null.
+  final Uri serverUri;
+
+  ServiceProtocolInfo(this.serverUri);
+
+  String toString() {
+    if (serverUri != null) {
+      return 'Dart VM Service Protocol v$majorVersion.$minorVersion '
+             'listening on $serverUri';
+    } else {
+      return 'Dart VM Service Protocol v$majorVersion.$minorVersion';
+    }
+  }
+}
+
+/// Access information about the service protocol and control the web server.
+class Service {
+  /// Get information about the service protocol.
+  static Future<ServiceProtocolInfo> getInfo() async {
+    // Port to receive response from service isolate.
+    final RawReceivePort receivePort = new RawReceivePort();
+    final Completer<Uri> uriCompleter = new Completer<Uri>();
+    receivePort.handler = (Uri uri) => uriCompleter.complete(uri);
+    // Request the information from the service isolate.
+    _getServerInfo(receivePort.sendPort);
+    // Await the response from the service isolate.
+    Uri uri = await uriCompleter.future;
+    // Close the port.
+    receivePort.close();
+    return new ServiceProtocolInfo(uri);
+  }
+
+  /// Control the web server that the service protocol is accessed through.
+  static Future<ServiceProtocolInfo> controlWebServer(
+      {bool enable: false}) async {
+    if (enable is! bool) {
+      throw new ArgumentError.value(enable,
+                                    'enable',
+                                    'Must be a bool');
+    }
+    // Port to receive response from service isolate.
+    final RawReceivePort receivePort = new RawReceivePort();
+    final Completer<Uri> uriCompleter = new Completer<Uri>();
+    receivePort.handler = (Uri uri) => uriCompleter.complete(uri);
+    // Request the information from the service isolate.
+    _webServerControl(receivePort.sendPort, enable);
+    // Await the response from the service isolate.
+    Uri uri = await uriCompleter.future;
+    // Close the port.
+    receivePort.close();
+    return new ServiceProtocolInfo(uri);
+  }
+}
+
+/// [sp] will receive a Uri or null.
+external void _getServerInfo(SendPort sp);
+
+/// [sp] will receive a Uri or null.
+external void _webServerControl(SendPort sp, bool enable);
+
+/// Returns the major version of the service protocol.
+external int _getServiceMajorVersion();
+
+/// Returns the minor version of the service protocol.
+external int _getServiceMinorVersion();
+