pkg/http_server: return a Future on VirtualDirectory.serveFile

dart/pkg/http_server/lib/src/virtual_directory.dart

 // Copyright (c) 2013, 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 http_server;
 
 
 // Used for signal a directory redirecting, where a tailing slash is missing.
 class _DirectoryRedirect {
   const _DirectoryRedirect();
@@ skipping 153 matching lines @@
    * This is usefull when e.g. overriding [directoryHandler] to redirect to
    * some index file.
    *
    * In the request contains the [HttpStatus.IF_MODIFIED_SINCE] header,
    * [serveFile] will send a [HttpStatus.NOT_MODIFIED] response if the file
    * was not changed.
    *
    * Note that if it was unabled to read from [file], the [request]s response
    * is closed with error-code [HttpStatus.NOT_FOUND].
    */
-  void serveFile(File file, HttpRequest request) {
+  Future serveFile(File file, HttpRequest request) {
     var response = request.response;
     // TODO(ajohnsen): Set up Zone support for these errors.
     file.lastModified().then((lastModified) {
       if (request.headers.ifModifiedSince != null &&
           !lastModified.isAfter(request.headers.ifModifiedSince)) {
         response.statusCode = HttpStatus.NOT_MODIFIED;
         response.close();
         return null;
       }
 
@@ skipping 46 matching lines @@
         file.openRead()
             .pipe(new _VirtualDirectoryFileStream(response, file.path))
             .catchError((_) {
               // TODO(kevmoo): log errors
             });
       });
     }).catchError((_) {
       response.statusCode = HttpStatus.NOT_FOUND;
       response.close();
     });
+    
+    return response.done;
   }
 
   void _serveDirectory(Directory dir, HttpRequest request) {
     if (_dirCallback != null) {
       _dirCallback(dir, request);
       return;
     }
     var response = request.response;
     dir.stat().then((stats) {
       if (request.headers.ifModifiedSince != null &&
@@ skipping 150 matching lines @@
 
   Future close() => new Future.value();
 
   void setMimeType(List<int> bytes) {
     var mimeType = lookupMimeType(path, headerBytes: bytes);
     if (mimeType != null) {
       response.headers.contentType = ContentType.parse(mimeType);
     }
   }
 }