dartfmt patch file side-stepping.

pkg/analyzer/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:convert';
 import 'dart:io';
 
 import 'package:args/args.dart';
 import 'package:path/path.dart' as path;
 
 import 'package:analyzer/src/services/formatter_impl.dart';
 
 
 const BINARY_NAME = 'dartfmt';
 final dartFileRegExp = new RegExp(r'^[^.].*\.dart$', caseSensitive: false);
 final argParser = _initArgParser();
 final defaultSelection = new Selection(-1, -1);
 
 var formatterSettings;
 
 CodeKind kind;
 bool machineFormat;
 bool overwriteFileContents;
 Selection selection;
-const followLinks = false;
+final List<String> paths = [];
+
+const FOLLOW_LINKS = false;
 
 
 main(args) {
   var options = argParser.parse(args);
   if (options['help']) {
     _printUsage();
     return;
   }
 
   _readOptions(options);
 
   if (options.rest.isEmpty) {
     _formatStdin(kind);
   } else {
-    _formatPaths(options.rest);
+    paths.addAll(options.rest);
+    _formatPaths(paths);
   }
 }
 
 _readOptions(options) {
   kind = _parseKind(options['kind']);
   machineFormat = options['machine'];
   overwriteFileContents = options['write'];
   selection = _parseSelection(options['selection']);
   formatterSettings =
       new FormatterOptions(codeTransforms: options['transform']);
@@ skipping 36 matching lines @@
 }
 
 _formatResource(resource) {
   if (resource is Directory) {
     _formatDirectory(resource);
   } else if (resource is File) {
     _formatFile(resource);
   }
 }
 
-_formatDirectory(dir) => dir.listSync(followLinks: followLinks)
+_formatDirectory(dir) => dir.listSync(followLinks: FOLLOW_LINKS)
     .forEach((resource) => _formatResource(resource));
 
 _formatFile(file) {
   if (_isDartFile(file)) {
+    if (_isPatchFile(file) && !paths.contains(file.path)) {
+      _log('Skipping patch file "${file.path}"');
+      return;
+    }
     try {
       var buffer = new StringBuffer();
       var rawSource = file.readAsStringSync();
       var formatted = _format(rawSource, CodeKind.COMPILATION_UNIT);
       if (overwriteFileContents) {
         file.writeAsStringSync(formatted);
       } else {
         print(formatted);
       }
     } catch (e) {
       _log('Unable to format "${file.path}": $e');
     }
   }
 }
 
+_isPatchFile(file) => file.path.endsWith('_patch.dart');
+
 _isDartFile(file) => dartFileRegExp.hasMatch(path.basename(file.path));
 
 _formatStdin(kind) {
   var input = new StringBuffer();
   stdin.transform(new Utf8Decoder())
       .listen((data) => input.write(data),
         onError: (error) => _log('Error reading from stdin'),
         onDone: () => print(_format(input.toString(), kind)));
 }
 
@@ skipping 58 matching lines @@
                      'offset': formatResult.selection.offset,
                      'length': formatResult.selection.length
                   }
     });
 
 /// Log the given [msg].
 _log(String msg) {
   //TODO(pquitslund): add proper log support
   print(msg);
 }