Add asynchronous versions of the methods on Directory.

runtime/bin/directory.dart

 // Copyright (c) 2011, 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.
 
 interface Directory factory _Directory {
   /**
    * Creates a directory object. The path is either a full path or
    * relative to the directory in which the Dart VM was
    * started.
    */
   Directory(String path);
 
   /**
-   * Returns whether a directory with this name already exists.
+   * Check whether a directory with this name already exists. If the
+   * operation completes successfully the [existsHandler] is called with
+   * the result. Otherwise the [errorHandler] is called.
+   */
+  void exists();
+
+  /**
+   * Synchronously check whether a directory with this name already exists.
    */
   bool existsSync();
 
   /**
    * Creates the directory with this name if it does not exist.
-   * Throw an exception if the directory already exists.
+   * If the directory is successfully created the [createHandler] is
+   * called. Otherwise the [errorHandler] is called.
+   */
+  void create();
+
+  /**
+   * Synchronously creates the directory with this name if it does not exist.
+   * Throws an exception if the directory already exists.
    */
   void createSync();
 
   /**
    * Creates a temporary directory with a name based on the current path.
    * This name and path is used as a template, and additional characters are
    * appended to it by the call to make a unique directory name.  If the
    * path is the empty string, a default system temp directory and name
    * are used for the template.
    * The path is modified to be the path of the new directory.
    * After the new directory is created, and the path modified, the callback
    * createTempHandler will be called.  The error handler is called if
    * the temporary directory cannot be created.
    */
   void createTemp();
 
   /**
-   * Synchronously creates a temporary directory with a name based on the current path.
-   * This name and path is used as a template, and additional characters are
-   * appended to it by the call to make a unique directory name.  If the
-   * path is the empty string, a default system temp directory and name
+   * Synchronously creates a temporary directory with a name based on the
+   * current path. This name and path is used as a template, and additional
+   * characters are appended to it by the call to make a unique directory name.
+   * If the path is the empty string, a default system temp directory and name
    * are used for the template.
    * The path is modified to be the path of the new directory.
    */
   void createTempSync();
 
   /**
+   * Deletes the directory with this name. If the operation completes
+   * successfully the [deleteHandler] is called. Otherwise the
+   * [errorHandler] is called.
+   */
+  void delete();
+
+  /**
    * Deletes the directory with this name. Throws an exception
    * if the directory is not empty or if deletion failed.
    */
   void deleteSync();
 
   /**
    * List the sub-directories and files of this
    * [Directory]. Optionally recurse into sub-directories. For each
    * file and directory, the file or directory handler is called. When
    * all directories have been listed the done handler is called. If
@@ skipping 17 matching lines @@
   void set fileHandler(void fileHandler(String file));
 
   /**
    * Set the handler that is called when a directory listing is
    * done. The handler is called with an indication of whether or not
    * the listing operation completed.
    */
   void set doneHandler(void doneHandler(bool completed));
 
   /**
+   * Set the handler that is called when checking if a directory with this
+   * name exists.
+   */
+  void set existsHandler(void existsHandler(bool exists));
+
+  /**
+   * Set the handler that is called when a directory is successfully created.
+   */
+  void set createHandler(void createHandler());
+
+  /**
    * Set the handler that is called when a temporary directory is
    * successfully created.
    */
   void set createTempHandler(void doneHandler(bool completed));
 
   /**
+   * Set the handler that is called when a directory is successfully
+   * deleted.
+   */
+  void set deleteHandler(void deleteHandler());
+
+  /**
    * Sets the handler that is called if there is an error while listing
    * or creating directories.
    */
   void set errorHandler(void errorHandler(String error));
 
   /**
    * Gets the path of this directory.
    */
   final String path;
 }
 
 
 class DirectoryException {
   const DirectoryException([String this.message, int this.errorCode = 0]);
   String toString() => "DirectoryException: $message";
   final String message;
   final int errorCode;
 }