Split off a Driver class from analysis server's HttpAnalysisServer.

pkg/analysis_server/lib/driver.dart

Index: pkg/analysis_server/lib/driver.dart
diff --git a/pkg/analysis_server/lib/driver.dart b/pkg/analysis_server/lib/driver.dart
new file mode 100644
index 0000000000000000000000000000000000000000..5fccb9d5d8ae5a71f99bdb328b6d82857acba3d7
--- /dev/null
+++ b/pkg/analysis_server/lib/driver.dart
@@ -0,0 +1,88 @@
+// 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 driver;
+
+import 'dart:io';
+
+import 'package:analysis_server/http_server.dart';
+import 'package:analysis_server/src/socket_server.dart';
+import 'package:args/args.dart';
+
+/**
+ * The [Driver] class represents a single running instance of the analysis
+ * server application.  It is responsible for parsing command line options
+ * and starting the HTTP and/or stdio servers.
+ */
+class Driver {
+  /**
+   * The name of the application that is used to start a server.
+   */
+  static const BINARY_NAME = 'server';
+
+  /**
+   * The name of the option used to print usage information.
+   */
+  static const String HELP_OPTION = "help";
+
+  /**
+   * The name of the option used to specify the port to which the server will
+   * connect.
+   */
+  static const String PORT_OPTION = "port";
+
+  SocketServer socketServer = new SocketServer();
+
+  HttpAnalysisServer httpServer;
+
+  Driver() {
+    httpServer = new HttpAnalysisServer(socketServer);
+  }
+
+  /**
+   * Use the given command-line arguments to start this server.
+   */
+  void start(List<String> args) {
+    ArgParser parser = new ArgParser();
+    parser.addFlag(HELP_OPTION, help:
+        "print this help message without starting a server", defaultsTo: false,
+        negatable: false);
+    parser.addOption(PORT_OPTION, help:
+        "[port] the port on which the server will listen");
+
+    ArgResults results = parser.parse(args);
+    if (results[HELP_OPTION]) {
+      _printUsage(parser);
+      return;
+    }
+    if (results[PORT_OPTION] == null) {
+      print('Missing required port number');
+      print('');
+      _printUsage(parser);
+      exitCode = 1;
+      return;
+    }
+
+    try {
+      int port = int.parse(results[PORT_OPTION]);
+      httpServer.serveHttp(port);
+    } on FormatException {
+      print('Invalid port number: ${results[PORT_OPTION]}');
+      print('');
+      _printUsage(parser);
+      exitCode = 1;
+      return;
+    }
+  }
+
+  /**
+   * Print information about how to use the server.
+   */
+  void _printUsage(ArgParser parser) {
+    print('Usage: $BINARY_NAME [flags]');
+    print('');
+    print('Supported flags are:');
+    print(parser.getUsage());
+  }
+}