Add argument check to Directory and Link constructors

sdk/lib/io/directory_impl.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.
 
 part of dart.io;
 
 class _Directory implements Directory {
   static const CREATE_REQUEST = 0;
   static const DELETE_REQUEST = 1;
   static const EXISTS_REQUEST = 2;
   static const CREATE_TEMP_REQUEST = 3;
   static const LIST_START_REQUEST = 4;
   static const LIST_NEXT_REQUEST = 5;
   static const LIST_STOP_REQUEST = 6;
   static const RENAME_REQUEST = 7;
 
-  _Directory(String this._path);
+  final String path;
+  SendPort _directoryService;
+
+  _Directory(String this.path) {
+    if (path is! String) {
+      throw new ArgumentError('${Error.safeToString(path)} '
+                              'is not a String');
+    }
+  }
+
   _Directory.fromPath(Path path) : this(path.toNativePath());
 
   external static String _current();
   external static _setCurrent(path);
   external static _createTemp(String template);
   external static int _exists(String path);
   external static _create(String path);
   external static _delete(String path, bool recursive);
   external static _rename(String path, String newPath);
   external static List _list(String path, bool recursive, bool followLinks);
   external static SendPort _newServicePort();
 
   static Directory get current => new _Directory(_current());
 
   static void set current(path) {
     if (path is Directory) path = path.path;
     var result = _setCurrent(path);
     if (result is ArgumentError) throw result;
     if (result is OSError) {
       throw new DirectoryException(
           "Setting current working directory failed", path, result);
     }
   }
 
   Future<bool> exists() {
     _ensureDirectoryService();
     List request = new List(2);
     request[0] = EXISTS_REQUEST;
-    request[1] = _path;
+    request[1] = path;
     return _directoryService.call(request).then((response) {
       if (_isErrorResponse(response)) {
         throw _exceptionOrErrorFromResponse(response, "Exists failed");
       }
       return response == 1;
     });
   }
 
   bool existsSync() {
-    if (_path is !String) {
-      throw new ArgumentError();
-    }
-    var result = _exists(_path);
+    var result = _exists(path);
     if (result is OSError) {
-      throw new DirectoryException("Exists failed", _path, result);
+      throw new DirectoryException("Exists failed", path, result);
     }
     return (result == 1);
   }
 
   Future<FileStat> stat() => FileStat.stat(path);
 
   FileStat statSync() => FileStat.statSync(path);
 
   // Compute the index of the first directory in the list that exists. If
   // none of the directories exist dirsToCreate.length is returned.
@@ skipping 13 matching lines @@
       }
     }
     if (future == null) {
       return new Future.value(notFound);
     } else {
       return future;
     }
   }
 
   Future<Directory> createRecursively() {
-    if (_path is !String) {
-      throw new ArgumentError();
-    }
-    var path = new Path(_path);
+    var path = new Path(path);
     var dirsToCreate = [];
     var terminator = path.isAbsolute ? '/' : '';
     while (path.toString() != terminator) {
       dirsToCreate.add(new Directory.fromPath(path));
       path = path.directoryPath;
     }
     return _computeExistingIndex(dirsToCreate).then((index) {
       var future;
       for (var i = index - 1; i >= 0 ; i--) {
         if (future == null) {
@@ skipping 10 matching lines @@
         return future.then((_) => this);
       }
     });
   }
 
   Future<Directory> create({recursive: false}) {
     if (recursive) return createRecursively();
     _ensureDirectoryService();
     List request = new List(2);
     request[0] = CREATE_REQUEST;
-    request[1] = _path;
+    request[1] = path;
     return _directoryService.call(request).then((response) {
       if (_isErrorResponse(response)) {
         throw _exceptionOrErrorFromResponse(response, "Creation failed");
       }
       return this;
     });
   }
 
   void createRecursivelySync() {
-    var path = new Path(_path);
+    var path = new Path(path);
     var dirsToCreate = [];
     var terminator = path.isAbsolute ? '/' : '';
     while (path.toString() != terminator) {
       var dir = new Directory.fromPath(path);
       if (dir.existsSync()) break;
       dirsToCreate.add(dir);
       path = path.directoryPath;
     }
     for (var i = dirsToCreate.length - 1; i >= 0; i--) {
       dirsToCreate[i].createSync();
     }
   }
 
   void createSync({recursive: false}) {
-    if (_path is !String) {
-      throw new ArgumentError();
-    }
     if (recursive) return createRecursivelySync();
-    var result = _create(_path);
+    var result = _create(path);
     if (result is OSError) {
-      throw new DirectoryException("Creation failed", _path, result);
+      throw new DirectoryException("Creation failed", path, result);
     }
   }
 
   Future<Directory> createTemp() {
     _ensureDirectoryService();
     List request = new List(2);
     request[0] = CREATE_TEMP_REQUEST;
-    request[1] = _path;
+    request[1] = path;
     return _directoryService.call(request).then((response) {
       if (_isErrorResponse(response)) {
         throw _exceptionOrErrorFromResponse(
             response, "Creation of temporary directory failed");
       }
       return new Directory(response);
     });
   }
 
   Directory createTempSync() {
-    if (_path is !String) {
-      throw new ArgumentError();
-    }
     var result = _createTemp(path);
     if (result is OSError) {
       throw new DirectoryException("Creation of temporary directory failed",
-                                   _path,
+                                   path,
                                    result);
     }
     return new Directory(result);
   }
 
   Future<Directory> delete({recursive: false}) {
     _ensureDirectoryService();
     List request = new List(3);
     request[0] = DELETE_REQUEST;
-    request[1] = _path;
+    request[1] = path;
     request[2] = recursive;
     return _directoryService.call(request).then((response) {
       if (_isErrorResponse(response)) {
         throw _exceptionOrErrorFromResponse(response, "Deletion failed");
       }
       return this;
     });
   }
 
   void deleteSync({recursive: false}) {
-    if (_path is !String) {
-      throw new ArgumentError();
-    }
-    var result = _delete(_path, recursive);
+    var result = _delete(path, recursive);
     if (result is OSError) {
-      throw new DirectoryException("Deletion failed", _path, result);
+      throw new DirectoryException("Deletion failed", path, result);
     }
   }
 
   Future<Directory> rename(String newPath) {
     _ensureDirectoryService();
     List request = new List(3);
     request[0] = RENAME_REQUEST;
-    request[1] = _path;
+    request[1] = path;
     request[2] = newPath;
     return _directoryService.call(request).then((response) {
       if (_isErrorResponse(response)) {
         throw _exceptionOrErrorFromResponse(response, "Rename failed");
       }
       return new Directory(newPath);
     });
   }
 
   Directory renameSync(String newPath) {
-    if (_path is !String || newPath is !String) {
+    if (newPath is !String) {
       throw new ArgumentError();
     }
-    var result = _rename(_path, newPath);
+    var result = _rename(path, newPath);
     if (result is OSError) {
-      throw new DirectoryException("Rename failed", _path, result);
+      throw new DirectoryException("Rename failed", path, result);
     }
     return new Directory(newPath);
   }
 
   static String _trimTrailingPathSeparators(String path) {
     // Don't handle argument errors here.
     if (path is! String) return path;
     if (Platform.operatingSystem == 'windows') {
       while (path.length > 1 &&
              (path.endsWith(Platform.pathSeparator) ||
               path.endsWith('/'))) {
         path = path.substring(0, path.length - 1);
       }
     } else {
       while (path.length > 1 && path.endsWith(Platform.pathSeparator)) {
         path = path.substring(0, path.length - 1);
       }
     }
     return path;
   }
 
   Stream<FileSystemEntity> list({bool recursive: false,
                                  bool followLinks: true}) {
     return new _AsyncDirectoryLister(_trimTrailingPathSeparators(path),
                                      recursive,
                                      followLinks).stream;
   }
 
   List listSync({bool recursive: false, bool followLinks: true}) {
-    if (_path is! String || recursive is! bool || followLinks is! bool) {
+    if (recursive is! bool || followLinks is! bool) {
       throw new ArgumentError();
     }
     return _list(_trimTrailingPathSeparators(path), recursive, followLinks);
   }
 
-  String get path => _path;
-
   String toString() => "Directory: '$path'";
 
   bool _isErrorResponse(response) {
     return response is List && response[0] != _SUCCESS_RESPONSE;
   }
 
   _exceptionOrErrorFromResponse(response, String message) {
     assert(_isErrorResponse(response));
     switch (response[_ERROR_RESPONSE_ERROR_TYPE]) {
       case _ILLEGAL_ARGUMENT_RESPONSE:
         return new ArgumentError();
       case _OSERROR_RESPONSE:
         var err = new OSError(response[_OSERROR_RESPONSE_MESSAGE],
                               response[_OSERROR_RESPONSE_ERROR_CODE]);
-        return new DirectoryException(message, _path, err);
+        return new DirectoryException(message, path, err);
       default:
         return new Exception("Unknown error");
     }
   }
 
   void _ensureDirectoryService() {
     if (_directoryService == null) {
       _directoryService = _newServicePort();
     }
   }
-
-  final String _path;
-  SendPort _directoryService;
 }
 
 class _AsyncDirectoryLister {
   static const int LIST_FILE = 0;
   static const int LIST_DIRECTORY = 1;
   static const int LIST_LINK = 2;
   static const int LIST_ERROR = 3;
   static const int LIST_DONE = 4;
 
   static const int RESPONSE_TYPE = 0;
@@ skipping 114 matching lines @@
       controller.addError(
           new DirectoryException("Directory listing failed",
                                  errorPath,
                                  err));
     } else {
       controller.addError(
           new DirectoryException("Internal error"));
     }
   }
 }