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

sdk/lib/io/file_system_entity.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 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);

[Bob Nystrom, 2013/03/06 19:02:52]

This feels wrong to me. "NOT FOUND" isn't a kind of file. I would prefer
throwing an exception for this case.

[Bill Hesse, 2013/03/07 09:53:12]

I think the exception can be harder to handle than dealing with the cases, since
we are probably handling cases already if we call this.  I'm not convinced by
the argument about "type" - this could also be called "status", or the name
could be changed from "NOT_FOUND" to "NONEXISTENT".

[Søren Gjesse, 2013/03/07 11:33:30]

I agree with Bill here. Lets call it "NONEXISTENT".

+  const FileSystemEntityType._internal(int this._type);
+  final int _type;
+  String toString() => ['FILE', 'DIRECTORY', 'LINK', 'NOT_FOUND'][_type];

[Bob Nystrom, 2013/03/06 19:02:52]

Why not just make the type the string instead of an int?

[Bill Hesse, 2013/03/07 09:53:12]

I'd like other's comments on this.  This is an implementation issue, that does
not affect the API.  Moving the "lookup" constructor to a factory in this class.

[Søren Gjesse, 2013/03/07 11:33:30]

This is an implementation issue so I don't care whether it is an int or a String
- it is not exposed.

+}
+
 /**
  * A [FileSystemEntity] is a common super class for [File] and
  * [Directory] objects.
  *
  * [FileSystemEntity] objects are returned from directory listing
  * operations. To determine if a FileSystemEntity is a [File] or a
  * [Directory], perform a type check:
  *
  *     if (entity is File) (entity as File).readAsStringSync();
  */
 abstract class FileSystemEntity {

[Bob Nystrom, 2013/03/06 19:02:52]

Tangential, but how about "Entry" for this type name? I believe that's the most
common word used to mean "file or directory".

[Bill Hesse, 2013/03/07 09:53:12]

I think that is a good idea too.  What do others think?

[Søren Gjesse, 2013/03/07 11:33:30]

I think Entry is a better name. I kind of says that to might not be anything
behind the path whether Entity indicate that there is an entity pointed to. It
is a long name, so we might as well just change it to FSEntry unless we find
something better soon.

   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})

[Søren Gjesse, 2013/03/06 17:47:33]

Use { } body for multiline methods.

[Bill Hesse, 2013/03/07 09:53:12]

Moved to a static method, and done.

On 2013/03/06 17:47:33, Søren Gjesse wrote:

+      => [FileSystemEntityType.FILE,
+          FileSystemEntityType.DIRECTORY,
+          FileSystemEntityType.LINK,
+          FileSystemEntityType.NOT_FOUND][_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);
+    }
+  }
 }