Add Bob's path library to pub.

utils/pub/pub.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.
 
 /**
  * The main entrypoint for the pub command line application.
  */
 library pub;
 
 import '../../pkg/args/lib/args.dart';
 import 'dart:io';
 import 'dart:math';
 import 'io.dart';
 import 'command_help.dart';
 import 'command_install.dart';
 import 'command_lish.dart';
 import 'command_update.dart';
 import 'command_version.dart';
 import 'entrypoint.dart';
 import 'exit_codes.dart' as exit_codes;
 import 'package.dart';
+import 'path.dart' as path;
 import 'pubspec.dart';
 import 'source.dart';
 import 'source_registry.dart';
 import 'system_cache.dart';
 import 'utils.dart';
 import 'version.dart';
 
 Version get pubVersion => new Version(0, 0, 0);
 
 /**
@@ skipping 177 matching lines @@
       }
 
       exit(_chooseExitCode(error));
     }
 
     var future = new Future.immediate(null);
     if (requiresEntrypoint) {
       // TODO(rnystrom): Will eventually need better logic to walk up
       // subdirectories until we hit one that looks package-like. For now, just
       // assume the cwd is it.
-      future = Entrypoint.load(currentWorkingDir, cache);
+      future = Entrypoint.load(path.current, cache);
     }
 
     future = future.chain((entrypoint) {
       this.entrypoint = entrypoint;
       try {
         var commandFuture = onRun();
         if (commandFuture == null) return new Future.immediate(true);
 
         return commandFuture;
       } catch (error, trace) {
         handleError(error, trace);
         return new Future.immediate(null);
       }
     });
 
     future = future.chain((_) => cache_.deleteTempDir());
 
     future.handleException((e) {
       if (e is PubspecNotFoundException && e.name == null) {
         e = 'Could not find a file named "pubspec.yaml" in the directory '
-          '$currentWorkingDir.';
+          '${path.current}.';
       } else if (e is PubspecHasNoNameException && e.name == null) {
         e = 'pubspec.yaml is missing the required "name" field (e.g. "name: '
-          '${basename(currentWorkingDir)}").';
+          '${basename(path.current)}").';
       }
 
       handleError(e, future.stackTrace);
     });
 
     // Explicitly exit on success to ensure that any dangling dart:io handles
     // don't cause the process to never terminate.
     future.then((_) => exit(0));
   }
 
@@ skipping 24 matching lines @@
     if (exception is HttpException || exception is HttpParserException ||
         exception is SocketIOException || exception is PubHttpException) {
       return exit_codes.UNAVAILABLE;
     } else if (exception is FormatException) {
       return exit_codes.DATA;
     } else {
       return 1;
     }
   }
 }