Add server options.

dart/pkg/dart2js_incremental/lib/src/options.dart

Index: dart/pkg/dart2js_incremental/lib/src/options.dart
diff --git a/dart/pkg/dart2js_incremental/lib/src/options.dart b/dart/pkg/dart2js_incremental/lib/src/options.dart
new file mode 100644
index 0000000000000000000000000000000000000000..ba1260fcb5663fa76032ce5494cbaf543cd4f3a1
--- /dev/null
+++ b/dart/pkg/dart2js_incremental/lib/src/options.dart
@@ -0,0 +1,134 @@
+// Copyright (c) 2015, 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 dart2js_incremental.options;
+
+class Options {
+  final List<String> arguments;
+  final Uri packageRoot;
+  final String host;
+  final int port;
+
+  Options({this.arguments, this.packageRoot, this.host, this.port});
+
+  static String extractArgument(String option, String short, {String long}) {
+    if (option.startsWith(short)) {
+      return option.substring(short.length);
+    }
+    if (long != null && option.startsWith(long)) {
+      return option.substring(long.length);
+    }
+    return null;
+  }
+
+  static Options parse(List<String> commandLine) {
+    Iterator<String> iterator = commandLine.iterator;
+    List<String> arguments = <String>[];
+    Uri packageRoot;
+    String host = "127.0.0.1";
+    int port = 0;
+    bool showHelp = false;
+    List<String> unknownOptions = <String>[];
+
+    LOOP: while (iterator.moveNext()) {
+      String option = iterator.current;
+      switch (option) {
+        case "-p":
+          iterator.moveNext();
+          packageRoot = Uri.base.resolve(iterator.current);
+          continue;
+
+        case "-h":
+          iterator.moveNext();
+          host = iterator.current;
+          continue;
+
+        case "-n":
+          iterator.moveNext();
+          port = int.parse(iterator.current);
+          continue;
+
+        case "--help":
+          showHelp = true;
+          continue;
+
+        case "--":
+          break LOOP;
+
+        default:
+          String argument;
+
+          argument = extractArgument(option, "-p", long: "--package-root");
+          if (argument != null) {
+            packageRoot = Uri.base.resolve(argument);
+            continue;
+          }
+
+          argument = extractArgument(option, "-h", long: "--host");
+          if (argument != null) {
+            host = argument;
+            continue;
+          }
+
+          argument = extractArgument(option, "-n", long: "--port");
+          if (argument != null) {
+            port = int.parse(option);
+            continue;
+          }
+
+          if (option.startsWith("-")) {
+            unknownOptions.add(option);
+            continue;
+          }
+
+          arguments.add(option);
+          break;
+      }
+    }
+    if (showHelp) {
+      print(USAGE);
+    }
+    if (!unknownOptions.isEmpty) {
+      print(USAGE);
+      print("Unknown options: '${unknownOptions.join('\', \'')}'");
+      return null;
+    }
+    while (iterator.moveNext()) {
+      arguments.add(iterator.current);
+    }
+    if (arguments.length > 1) {
+      print(USAGE);
+      print("Extra arguments: '${arguments.skip(1).join('\', \'')}'");
+      return null;
+    }
+    if (packageRoot == null) {
+      packageRoot = Uri.base.resolve('packages/');
+    }
+    return new Options(
+        arguments: arguments, packageRoot: packageRoot, host: host, port: port);
+  }
+}
+
+const String USAGE = """
+Usage: server.dart [options] [--] documentroot
+
+Development web server which serves files relative to [documentroot]. If a file
+is missing, and the requested file name ends with '.dart.js', the server will
+look for a file with the same name save '.js', compile it to JavaScript, and
+serve that file instead.
+
+Supported options:
+
+  -p<path>, --package-root=<path>
+    Where to find packages, that is, "package:..." imports.
+
+  -h<name>, --host=<name>
+    Host name to bind the web server to (default 127.0.0.1).
+
+  -n<port>, --port=<port>
+    Port number to bind the web server to.
+
+  --help
+    Show this message.
+""";