dart:io | Add FileSystemEntity.typeSync to test for symbolic links.

sdk/lib/io/file_system_entity.dart

Index: sdk/lib/io/file_system_entity.dart
diff --git a/sdk/lib/io/file_system_entity.dart b/sdk/lib/io/file_system_entity.dart
index bbe8cd5975f0f2d47cad3aeafe22ef76f1e4ddb9..e13477b1c41e5b6c11e732e01977ccaa47d985b9 100644
--- a/sdk/lib/io/file_system_entity.dart
+++ b/sdk/lib/io/file_system_entity.dart
@@ -4,6 +4,23 @@
 
 part of dart.io;
 
+class FileSystemEntityType {
+  static const FILE = const FileSystemEntityType._internal(0);
+  static const DIRECTORY = const FileSystemEntityType._internal(1);
+  static const LINK = const FileSystemEntityType._internal(2);
+  static const NOT_FOUND = const FileSystemEntityType._internal(3);
+  static const _typeList = const [FileSystemEntityType.FILE,
+                                  FileSystemEntityType.DIRECTORY,
+                                  FileSystemEntityType.LINK,
+                                  FileSystemEntityType.NOT_FOUND];
+  const FileSystemEntityType._internal(int this._type);
+
+  static FileSystemEntityType _lookup(int type) => _typeList[type];
+  String toString() => const ['FILE', 'DIRECTORY', 'LINK', 'NOT_FOUND'][_type];
+
+  final int _type;
+}
+
 /**
  * A [FileSystemEntity] is a common super class for [File] and
  * [Directory] objects.
@@ -16,4 +33,30 @@ part of dart.io;
  */
 abstract class FileSystemEntity {
   String get path;
+
+  external static int _getType(String path, bool followLinks);
+
+  static int _getTypeSync(String path, bool followLinks) {
+    var result = _getType(path, followLinks);
+    _throwIfError(result, 'Error getting type of FileSystemEntity');
+    return result;
+  }
+
+  static FileSystemEntityType typeSync(String path, {bool followLinks: true})
+      => FileSystemEntityType._lookup(_getTypeSync(path, followLinks));
+
+  static bool isLinkSync(String path) =>
+      (_getTypeSync(path, false) == FileSystemEntityType.LINK._type);
+
+  static bool isFileSync(String path) =>
+      (_getTypeSync(path, true) == FileSystemEntityType.FILE._type);
+
+  static bool isDirectorySync(String path) =>
+      (_getTypeSync(path, true) == FileSystemEntityType.DIRECTORY._type);
+
+  static _throwIfError(Object result, String msg) {
+    if (result is OSError) {
+      throw new FileIOException(msg, result);
+    }
+  }
 }