Add File.renameSync() to virtual file system.

pkg/analyzer/lib/file_system/memory_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.memory_file_system;
 
 import 'dart:async';
 import 'dart:collection';
 import 'dart:core' hide Resource;
 
@@ skipping 141 matching lines @@
     } else if (resource is _MemoryFolder) {
       _notifyWatchers(path, ChangeType.ADD);
       return resource;
     } else {
       String message =
           'Folder expected at ' "'$path'" 'but ${resource.runtimeType} found';
       throw new ArgumentError(message);
     }
   }
 
+  void renameFileSync(String path, String newPath) {
+    if (newPath == path) {
+      return;
+    }
+    if (_pathToResource[newPath] is _MemoryFolder) {
+      throw new FileSystemException(
+          path, 'Could not be renamed: $newPath is a folder.');
+    }
+    _pathToResource.remove(path);
+    _pathToContent[newPath] = _pathToContent.remove(path);
+    _pathToBytes[newPath] = _pathToBytes.remove(path);
+    _pathToTimestamp[newPath] = _pathToTimestamp.remove(path);
+    _pathToWatchers[newPath] = _pathToWatchers.remove(path);

[Brian Wilkerson, 2016/03/17 19:31:00]

Does this need to call _notifyWatchers?

+  }
+
   File updateFile(String path, String content, [int stamp]) {
     path = pathContext.normalize(path);
     newFolder(pathContext.dirname(path));
     _MemoryFile file = new _MemoryFile(this, path);
     _pathToResource[path] = file;
     _pathToContent[path] = content;
     _pathToTimestamp[path] = stamp != null ? stamp : nextStamp++;
     _notifyWatchers(path, ChangeType.MODIFY);
     return file;
   }
@@ skipping 35 matching lines @@
         List<StreamController<WatchEvent>> streamControllers) {
       if (watcherPath == path || pathContext.isWithin(watcherPath, path)) {
         for (StreamController<WatchEvent> streamController
             in streamControllers) {
           streamController.add(new WatchEvent(changeType, path));
         }
       }
     });
   }
 
-  void _setFileBytes(String path, List<int> bytes) {
+  void _setFileBytes(_MemoryFile file, List<int> bytes) {
+    String path = file.path;
+    _pathToResource[path] = file;
     _pathToBytes[path] = bytes;
     _pathToTimestamp[path] = nextStamp++;
     _notifyWatchers(path, ChangeType.MODIFY);
   }
 }
 
 /**
  * An in-memory implementation of [File] which acts like a symbolic link to a
  * non-existent file.
  */
@@ skipping 36 matching lines @@
   List<int> readAsBytesSync() {
     throw new FileSystemException(path, 'File could not be read');
   }
 
   @override
   String readAsStringSync() {
     throw new FileSystemException(path, 'File could not be read');
   }
 
   @override
+  Resource renameSync(String newPath) {
+    throw new FileSystemException(path, 'File could not be renamed');
+  }
+
+  @override
   void writeAsBytesSync(List<int> bytes) {
     throw new FileSystemException(path, 'File could not be written');
   }
 }
 
 /**
  * An in-memory implementation of [File].
  */
 class _MemoryFile extends _MemoryResource implements File {
   _MemoryFile(MemoryResourceProvider provider, String path)
@@ skipping 44 matching lines @@
   @override
   String readAsStringSync() {
     String content = _provider._pathToContent[path];
     if (content == null) {
       throw new FileSystemException(path, 'File "$path" does not exist.');
     }
     return content;
   }
 
   @override
+  File renameSync(String newPath) {
+    _provider.renameFileSync(path, newPath);
+    return _provider._newFile(newPath);
+  }
+
+  @override
   void writeAsBytesSync(List<int> bytes) {
-    _provider._setFileBytes(path, bytes);
+    _provider._setFileBytes(this, bytes);
   }
 }
 
 /**
  * An in-memory implementation of [Source].
  */
 class _MemoryFileSource extends Source {
   /**
    * Map from encoded URI/filepath pair to a unique integer identifier.  This
    * identifier is used for equality tests and hash codes.
@@ skipping 196 matching lines @@
   bool operator ==(other) {
     if (runtimeType != other.runtimeType) {
       return false;
     }
     return path == other.path;
   }
 
   @override
   String toString() => path;
 }