Formatter stdin processing support.

pkg/analyzer_experimental/bin/formatter.dart

 #!/usr/bin/env 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.
 
 import 'dart:io';
+import 'dart:utf';
 
 import 'package:args/args.dart';
 import 'package:path/path.dart' as path;
 
 import 'package:analyzer_experimental/src/services/formatter_impl.dart';
 
 
 const BINARY_NAME = 'dartfmt';
 final dartFileRegExp = new RegExp(r'^[^.].*\.dart$', caseSensitive: false);
 final argParser = _initArgParser();
@@ skipping 50 matching lines @@
       }
     } catch (e) {
       _log('Unable to format "${file.path}": $e');
     }
   }
 }
 
 _isDartFile(file) => dartFileRegExp.hasMatch(path.basename(file.path));
 
 _formatStdin(options) {
-  _log('not supported yet!');
-//  stdin.transform(new StringDecoder())
-//      .listen((String data) => print(data),
-//        onError: (error) => print('Error reading from stdin'),
-//        onDone: () => print('Finished reading data'));
+  var input = new StringBuffer();
+  stdin.transform(new Utf8DecoderTransformer())
+      .listen((data) => input.write(data),
+        onError: (error) => _log('Error reading from stdin'),
+        onDone: () => print(_formatCU(input.toString())));
 }
 
 /// Initialize the arg parser instance.
 ArgParser _initArgParser() {
   // NOTE: these flags are placeholders only!
   var parser = new ArgParser();
   parser.addFlag('write', abbr: 'w', negatable: false,
       help: 'Write reformatted sources to files (overwriting contents).  '
             'Do not print reformatted sources to standard output.');
   parser.addFlag('help', abbr: 'h', negatable: false,
@@ skipping 22 matching lines @@
 
 /// Format the given [src] as a compilation unit.
 String _formatCU(src, {options: const FormatterOptions()}) =>
     new CodeFormatter(options).format(CodeKind.COMPILATION_UNIT, src);
 
 /// Log the given [msg].
 _log(String msg) {
   //TODO(pquitslund): add proper log support
   print(msg);
 }