Dart SDK Spelling b, c, and d.

pkg/analysis_server/lib/src/source/caching_pub_package_map_provider.dart

 // 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 source.caching_pub_package_map_provider;
 
 import 'dart:convert';
 import 'dart:core';
 import 'dart:io' as io;
 
@@ skipping 107 matching lines @@
         }
       }
     }
     int runCount = 0;
     PackageMapInfo info;
     while (true) {
       // Capture the current time so that we can tell if an input file
       // has changed while running pub list. This is done
       // by writing to a file rather than getting millisecondsSinceEpoch
       // because file modification time has different granularity
-      // on diferent systems.
+      // on different systems.
       int startStamp;
       try {
         startStamp = _writeFile(_touchFile, 'touch');
       } catch (exception, stackTrace) {
         AnalysisEngine.instance.logger.logInformation(
             'Exception writing $_touchFile\n$exception\n$stackTrace');
         startStamp = new DateTime.now().millisecondsSinceEpoch;
       }
       // computePackageMap calls parsePackageMap which caches the result
       info = super.computePackageMap(folder);
@@ skipping 112 matching lines @@
     // TODO(danrubel) This implementation assumes that
     // two separate processes are not accessing the cache file at the same time
     io.File file = new io.File(cacheFile.path);
     if (!file.parent.existsSync()) {
       file.parent.createSync(recursive: true);
     }
     file.writeAsStringSync(content, flush: true);
     return file.lastModifiedSync().millisecondsSinceEpoch;
   }
 }