Validate cache consistency asynchronously. Compute modification times of physical files in a separa…

pkg/analyzer/lib/file_system/file_system.dart

 // Copyright (c) 2014, 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.
 
 library analyzer.file_system.file_system;
 
 import 'dart:async';
 
 import 'package:analyzer/src/generated/source.dart';
 import 'package:analyzer/src/util/absolute_path.dart';
@@ skipping 180 matching lines @@
   File getFile(String path);
 
   /**
    * Return a [Folder] that corresponds to the given [path].
    *
    * A folder may or may not exist at this location.
    */
   Folder getFolder(String path);
 
   /**
+   * Complete with a list of modification times for the given [sources].
+   */
+  Future<List<int>> getModificationTimes(List<Source> sources);
+
+  /**
    * Return the [Resource] that corresponds to the given [path].
    */
   Resource getResource(String path);
 
   /**
    * Return the folder in which the plugin with the given [pluginId] can store
    * state that will persist across sessions. The folder returned for a given id
    * will not be returned for a different id, ensuring that plugins do not need
    * to be concerned with file name collisions with other plugins, assuming that
    * the plugin ids are unique. The plugin ids must be valid folder names.
    */
   Folder getStateLocation(String pluginId);
 }
 
 /**
  * A [UriResolver] for [Resource]s.
  */
 class ResourceUriResolver extends UriResolver {
   /**
    * The name of the `file` scheme.
    */
   static final String FILE_SCHEME = "file";
 
   final ResourceProvider _provider;
 
   ResourceUriResolver(this._provider);
 
+  ResourceProvider get provider => _provider;
+
   @override
   Source resolveAbsolute(Uri uri, [Uri actualUri]) {
     if (!isFileUri(uri)) {
       return null;
     }
     Resource resource =
         _provider.getResource(_provider.pathContext.fromUri(uri));
     if (resource is File) {
       return resource.createSource(actualUri ?? uri);
     }
     return null;
   }
 
   @override
   Uri restoreAbsolute(Source source) =>
       _provider.pathContext.toUri(source.fullName);
 
-  ResourceProvider get provider => _provider;
-
   /**
    * Return `true` if the given [uri] is a `file` URI.
    */
   static bool isFileUri(Uri uri) => uri.scheme == FILE_SCHEME;
 }