Add a Resource.parent getter, which gets the parent directory.

pkg/analysis_server/lib/src/resource.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 resource;
 
 import 'dart:async';
 import 'dart:collection';
 import 'dart:io' as io;
 
@@ skipping 51 matching lines @@
   /**
    * Return the full path to this resource.
    */
   String get path;
 
   /**
    * Return a short version of the name that can be displayed to the user to
    * denote this resource.
    */
   String get shortName;
+
+  /**
+   * Return the [Folder] that contains this resource, or null if this resource

[scheglov, 2014/06/25 21:44:25]

`null` ?

"is a root folder" ?

[Paul Berry, 2014/06/26 15:03:08]

Done.

+   * is a root directory.
+   */
+  Folder get parent;
 }
 
 
 /**
  * Instances of the class [ResourceProvider] convert [String] paths into
  * [Resource]s.
  */
 abstract class ResourceProvider {
   /**
    * Return the [Resource] that corresponds to the given [path].
@@ skipping 25 matching lines @@
   bool get exists => _provider._pathToResource.containsKey(path);
 
   @override
   get hashCode => path.hashCode;
 
   @override
   String get shortName => posix.basename(path);
 
   @override
   String toString() => path;
+
+  @override
+  Folder get parent {
+    String parentPath = posix.dirname(path);
+    if (parentPath == path) {
+      return null;
+    }
+    return _provider.getResource(parentPath);
+  }
 }
 
 
 /**
  * An in-memory implementation of [File].
  */
 class _MemoryFile extends _MemoryResource implements File {
   _MemoryFile(MemoryResourceProvider provider, String path) :
       super(provider, path);
 
@@ skipping 156 matching lines @@
       resource = new _MemoryFile(this, path);
     }
     return resource;
   }
 
   Folder newFolder(String path) {
     path = posix.normalize(path);
     if (!path.startsWith('/')) {
       throw new ArgumentError("Path must start with '/'");
     }
-    _MemoryFolder folder = null;
-    String partialPath = "";
-    for (String pathPart in path.split('/')) {
-      if (pathPart.isEmpty) {
-        continue;
+    _MemoryResource resource = _pathToResource[path];
+    if (resource == null) {
+      String parentPath = posix.dirname(path);
+      if (parentPath != path) {
+        newFolder(parentPath);
       }
-      partialPath += '/' + pathPart;
-      _MemoryResource resource = _pathToResource[partialPath];
-      if (resource == null) {
-        folder = new _MemoryFolder(this, partialPath);
-        _pathToResource[partialPath] = folder;
-        _pathToTimestamp[partialPath] = nextStamp++;
-      } else if (resource is _MemoryFolder) {
-        folder = resource;
-      } else {
-        String message = 'Folder expected at '
-                         "'$partialPath'"
-                         'but ${resource.runtimeType} found';
-        throw new ArgumentError(message);
-      }
+      _MemoryFolder folder = new _MemoryFolder(this, path);
+      _pathToResource[path] = folder;
+      _pathToTimestamp[path] = nextStamp++;
+      return folder;
+    } else if (resource is _MemoryFolder) {
+      return resource;
+    } else {
+      String message = 'Folder expected at '
+                       "'$path'"
+                       'but ${resource.runtimeType} found';
+      throw new ArgumentError(message);
     }
-    return folder;
   }
 
   File newFile(String path, String content) {
     path = posix.normalize(path);
     newFolder(posix.dirname(path));
     _MemoryFile file = new _MemoryFile(this, path);
     _pathToResource[path] = file;
     _pathToContent[path] = content;
     _pathToTimestamp[path] = nextStamp++;
     _notifyWatchers(path, ChangeType.ADD);
@@ skipping 102 matching lines @@
   String get path => _entry.absolute.path;
 
   @override
   get hashCode => _entry.hashCode;
 
   @override
   String get shortName => basename(path);
 
   @override
   String toString() => path;
+
+  @override
+  Folder get parent {
+    String parentPath = dirname(path);
+    if (parentPath == path) {
+      return null;
+    }
+    return new _PhysicalFolder(new io.Directory(parentPath));
+  }
 }
 
 
 /**
  * A `dart:io` based implementation of [ResourceProvider].
  */
 class PhysicalResourceProvider implements ResourceProvider {
   static final PhysicalResourceProvider INSTANCE = new PhysicalResourceProvider._();
 
   PhysicalResourceProvider._();
@@ skipping 51 matching lines @@
   }
 
   /**
    * Return `true` if the given URI is a `file` URI.
    *
    * @param uri the URI being tested
    * @return `true` if the given URI is a `file` URI
    */
   static bool _isFileUri(Uri uri) => uri.scheme == _FILE_SCHEME;
 }