Use patching for dart:io.

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.
 
 
 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_REQUEST = 4;
   static const RENAME_REQUEST = 5;
 
   static const SUCCESS_RESPONSE = 0;
   static const ILLEGAL_ARGUMENT_RESPONSE = 1;
   static const OSERROR_RESPONSE = 2;
 
   _Directory(String this._path);
   _Directory.fromPath(Path path) : this(path.toNativePath());
   _Directory.current() : this(_current());
 
-  static String _current() native "Directory_Current";
-  static _createTemp(String template) native "Directory_CreateTemp";
-  static int _exists(String path) native "Directory_Exists";
-  static _create(String path) native "Directory_Create";
-  static _delete(String path, bool recursive) native "Directory_Delete";
-  static _rename(String path, String newPath) native "Directory_Rename";
-  static SendPort _newServicePort() native "Directory_NewServicePort";
+  external static String _current();
+  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 SendPort _newServicePort();
 
   Future<bool> exists() {
     _ensureDirectoryService();
     List request = new List(2);
     request[0] = EXISTS_REQUEST;
     request[1] = _path;
     return _directoryService.call(request).transform((response) {
       if (_isErrorResponse(response)) {
-        throw _exceptionFromResponse(response, "Exists failed");
+        throw _exceptionOrErrorFromResponse(response, "Exists failed");
       }
       return response == 1;
     });
   }
 
   bool existsSync() {
     if (_path is !String) {
       throw new ArgumentError();
     }
     var result = _exists(_path);
     if (result is OSError) {
       throw new DirectoryIOException("Exists failed", _path, result);
     }
     return (result == 1);
   }
 
   Future<Directory> create() {
     _ensureDirectoryService();
     List request = new List(2);
     request[0] = CREATE_REQUEST;
     request[1] = _path;
     return _directoryService.call(request).transform((response) {
       if (_isErrorResponse(response)) {
-        throw _exceptionFromResponse(response, "Creation failed");
+        throw _exceptionOrErrorFromResponse(response, "Creation failed");
       }
       return this;
     });
   }
 
   void createSync() {
     if (_path is !String) {
       throw new ArgumentError();
     }
     var result = _create(_path);
     if (result is OSError) {
       throw new DirectoryIOException("Creation failed", _path, result);
     }
   }
 
   Future<Directory> createTemp() {
     _ensureDirectoryService();
     List request = new List(2);
     request[0] = CREATE_TEMP_REQUEST;
     request[1] = _path;
     return _directoryService.call(request).transform((response) {
       if (_isErrorResponse(response)) {
-        throw _exceptionFromResponse(response,
-                                     "Creation of temporary directory failed");
+        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 DirectoryIOException("Creation of temporary directory failed",
                                      _path,
                                      result);
     }
     return new Directory(result);
   }
 
   Future<Directory> _deleteHelper(bool recursive, String errorMsg) {
     _ensureDirectoryService();
     List request = new List(3);
     request[0] = DELETE_REQUEST;
     request[1] = _path;
     request[2] = recursive;
     return _directoryService.call(request).transform((response) {
       if (_isErrorResponse(response)) {
-        throw _exceptionFromResponse(response, errorMsg);
+        throw _exceptionOrErrorFromResponse(response, errorMsg);
       }
       return this;
     });
-    return completer.future;
   }
 
   Future<Directory> delete() {
     return _deleteHelper(false, "Deletion failed");
   }
 
   void deleteSync() {
     if (_path is !String) {
       throw new ArgumentError();
     }
@@ skipping 18 matching lines @@
   }
 
   Future<Directory> rename(String newPath) {
     _ensureDirectoryService();
     List request = new List(3);
     request[0] = RENAME_REQUEST;
     request[1] = _path;
     request[2] = newPath;
     return _directoryService.call(request).transform((response) {
       if (_isErrorResponse(response)) {
-        throw _exceptionFromResponse(response, "Rename failed");
+        throw _exceptionOrErrorFromResponse(response, "Rename failed");
       }
       return new Directory(newPath);
     });
   }
 
   Directory renameSync(String newPath) {
     if (_path is !String || newPath is !String) {
       throw new ArgumentError();
     }
     var result = _rename(_path, newPath);
     if (result is OSError) {
       throw new DirectoryIOException("Rename failed", _path, result);
     }
     return new Directory(newPath);
   }
 
   DirectoryLister list({bool recursive: false}) {
     return new _DirectoryLister(_path, recursive);
   }
 
   String get path { return _path; }
 
   bool _isErrorResponse(response) {
     return response is List && response[0] != _SUCCESS_RESPONSE;
   }
 
-  Exception _exceptionFromResponse(response, String message) {
+  _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 DirectoryIOException(message, _path, err);
       default:
         return new Exception("Unknown error");
@@ skipping 92 matching lines @@
     } else {
       throw e;
     }
   }
 
   Function _onDir;
   Function _onFile;
   Function _onDone;
   Function _onError;
 }