Add observatory_pub_packages snapshot to third_party

observatory_pub_packages/csslib/src/options.dart

+// Copyright (c) 2012, 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 csslib.src.options;
+
+import 'package:args/args.dart';
+
+class PreprocessorOptions {
+  /** Generate polyfill code (e.g., var, etc.) */
+  final bool polyfill;
+
+  /** Report warnings as errors. */
+  final bool warningsAsErrors;
+
+  /** Throw an exception on warnings (not used by command line tool). */
+  final bool throwOnWarnings;
+
+  /** Throw an exception on errors (not used by command line tool). */
+  final bool throwOnErrors;
+
+  /** True to show informational messages. The `--verbose` flag. */
+  final bool verbose;
+
+  /** True to show warning messages for bad CSS.  The '--checked' flag. */
+  final bool checked;
+
+  // TODO(terry): Add mixin support and nested rules.
+  /**
+   * Subset of Less commands enabled; disable with '--no-less'.
+   * Less syntax supported:
+   * - @name at root level statically defines variables resolved at compilation
+   * time.  Essentially a directive e.g., @var-name.
+   */
+  final bool lessSupport;
+
+  /** Whether to use colors to print messages on the terminal. */
+  final bool useColors;
+
+  /** File to process by the compiler. */
+  String inputFile;
+
+  // We could make this faster, if it ever matters.
+  factory PreprocessorOptions() => parse(['']);
+
+  PreprocessorOptions.fromArgs(ArgResults args)
+    : warningsAsErrors = args['warnings_as_errors'],
+      throwOnWarnings = args['throw_on_warnings'],
+      throwOnErrors = args['throw_on_errors'],
+      verbose = args['verbose'],
+      checked = args['checked'],
+      lessSupport = args['less'],
+      useColors = args['colors'],
+      polyfill = args['polyfill'],
+      inputFile = args.rest.length > 0 ? args.rest[0] : null;
+
+  // tool.dart [options...] <css file>
+  static PreprocessorOptions parse(List<String> arguments) {
+    var parser = new ArgParser()
+      ..addFlag('verbose', abbr: 'v', defaultsTo: false, negatable: false,
+          help: 'Display detail info')
+      ..addFlag('checked', defaultsTo: false, negatable: false,
+          help: 'Validate CSS values invalid value display a warning message')
+      ..addFlag('less', defaultsTo: true, negatable: true,
+          help: 'Supports subset of Less syntax')
+      ..addFlag('suppress_warnings', defaultsTo: true,
+          help: 'Warnings not displayed')
+      ..addFlag('warnings_as_errors', defaultsTo: false,
+          help: 'Warning handled as errors')
+      ..addFlag('throw_on_errors', defaultsTo: false,
+          help: 'Throw on errors encountered')
+      ..addFlag('throw_on_warnings', defaultsTo: false,
+          help: 'Throw on warnings encountered')
+      ..addFlag('colors', defaultsTo: true,
+          help: 'Display errors/warnings in colored text')
+      ..addFlag('polyfill', defaultsTo: false,
+          help: 'Generate polyfill for new CSS features')
+      ..addFlag('help', abbr: 'h', defaultsTo: false, negatable: false,
+          help: 'Displays this help message');
+
+    try {
+      var results = parser.parse(arguments);
+      if (results['help'] || results.rest.length == 0) {
+        showUsage(parser);
+        return null;
+      }
+      return new PreprocessorOptions.fromArgs(results);
+    } on FormatException catch (e) {
+      print(e.message);
+      showUsage(parser);
+      return null;
+    }
+  }
+
+  static showUsage(parser) {
+    print('Usage: css [options...] input.css');
+    print(parser.getUsage());
+  }
+
+}