Switch from interfaces to abstract classes in dart:io.

runtime/bin/directory.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.
 
 /**
  * [Directory] objects are used for working with directories.
  */
-interface Directory default _Directory {
+abstract class Directory {
   /**
    * Creates a directory object. The path is either an absolute path,
    * or it is a relative path which is interpreted relative to the directory
    * in which the Dart VM was started.
    */
-  Directory(String path);
+  factory Directory(String path) => new _Directory(path);
 
   /**
    * Creates a directory object from a Path object. The path is either
    * an absolute path, or it is a relative path which is interpreted
    * relative to the directory in which the Dart VM was started.
    */
-  Directory.fromPath(Path path);
+  factory Directory.fromPath(Path path) => new _Directory.fromPath(path);
 
   /**
    * Creates a directory object pointing to the current working
    * directory.
    */
-  Directory.current();
+  factory Directory.current() => new _Directory.current();
 
   /**
    * Check whether a directory with this name already exists. Returns
    * a [:Future<bool>:] that completes with the result.
    */
   Future<bool> exists();
 
   /**
    * Synchronously check whether a directory with this name already exists.
    */
@@ skipping 81 matching lines @@
    */
   Directory renameSync(String newPath);
 
   /**
    * List the sub-directories and files of this
    * [Directory]. Optionally recurse into sub-directories. Returns a
    * [DirectoryLister] object representing the active listing
    * operation. Handlers for files and directories should be
    * registered on this DirectoryLister object.
    */
-  DirectoryLister list([bool recursive]);
+  DirectoryLister list([bool recursive = false]);
 
   /**
    * Gets the path of this directory.
    */
   final String path;
 }
 
 
 /**
  * A [DirectoryLister] represents an actively running listing operation.
  *
  * For each file and directory, the file or directory handler is
  * called. When all directories have been listed the done handler is
  * called. If the listing operation is recursive, the error handler is
  * called if a subdirectory cannot be opened for listing.
  */
-interface DirectoryLister default _DirectoryLister {
+abstract class DirectoryLister {
   /**
    * Sets the directory handler that is called for all directories
    * during listing. The directory handler is called with the full
    * path of the directory.
    */
   void set onDir(void onDir(String dir));
 
   /**
    * Sets the handler that is called for all files during listing. The
    * file handler is called with the full path of the file.
@@ skipping 35 matching lines @@
       if (path != null) {
         sb.add(", path = $path");
       }
     }
     return sb.toString();
   }
   final String message;
   final String path;
   final OSError osError;
 }