Posix metadata

pkgs/io_file/lib/src/file_system.dart

@@ -18,6 +18,8 @@ abstract interface class Metadata {
   bool get isFile;
   bool get isDirectory;
   bool get isLink;
+
+  // Size of directories and links is platform specific.
   int get size;
 }
 

pkgs/io_file/lib/src/vm_posix_file_system.dart

@@ -50,6 +50,45 @@ int _tempFailureRetry(int Function() f) {
   return result;
 }
 
+/// File system entity data available on Windows.
+final class PosixMetadata implements Metadata {
+  final int _mode;
+  final int _flags;
+
+  int get _fmt => _mode & libc.S_IFMT;
+
+  @override
+  bool get isDirectory => _fmt == libc.S_IFDIR;
+
+  @override
+  bool get isFile => !(isDirectory || isLink);
+
+  @override
+  bool get isLink => _fmt == libc.S_IFLNK;
+
+  @override
+  final int size;
+
+  bool get isHidden {
+    if (io.Platform.isIOS || io.Platform.isMacOS) {
+      return _flags & libc.UF_HIDDEN != 0;
+    }
+    throw UnsupportedError('isHidden is only supported on iOS/macOS');
+  }
+
+  PosixMetadata._(this._mode, this._flags, this.size);
+
+  /// TODO(bquinlan): Document this constructor.
+  ///
+  /// Make sure to reference:
+  /// [File Attribute Constants](https://learn.microsoft.com/en-us/windows/win32/fileio/file-attribute-constants)
+  factory PosixMetadata.fromFileAttributes({
+    required int mode,
+    int flags = 0,
+    int size = 0,
+  }) => PosixMetadata._(mode, flags, size);
+}
+
 /// The POSIX `read` function.
 ///
 /// See https://pubs.opengroup.org/onlinepubs/9699919799/functions/read.html
@@ -112,9 +151,20 @@ final class PosixFileSystem extends FileSystem {
       });
 
   @override
-  Metadata metadata(String path) {
-    throw UnimplementedError();
-  }
+  PosixMetadata metadata(String path) => ffi.using((arena) {
+    final stat = arena<libc.Stat>();
+
+    if (libc.lstat(path.toNativeUtf8(allocator: arena).cast(), stat) == -1) {
+      final errno = libc.errno;
+      throw _getError(errno, 'stat failed', path);
+    }
+
+    return PosixMetadata.fromFileAttributes(
+      mode: stat.ref.st_mode,
+      flags: stat.ref.st_flags,
+      size: stat.ref.st_size,
+    );
+  });
 
   @override
   void removeDirectory(String path) => ffi.using((arena) {

pkgs/io_file/test/metadata_apple_test.dart

@@ -0,0 +1,51 @@
+// Copyright (c) 2025, 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.
+
+@TestOn('ios || mac-os')
+library;
+
+import 'dart:ffi';
+import 'dart:io';
+
+import 'package:ffi/ffi.dart';
+import 'package:io_file/src/vm_posix_file_system.dart';
+import 'package:stdlibc/stdlibc.dart' as stdlibc;
+import 'package:test/test.dart';
+
+import 'test_utils.dart';
+
+@Native<Int Function(Pointer<Utf8>, Uint32)>(isLeaf: false)
+external int chflags(Pointer<Utf8> buf, int count);
+
+void main() {
+  final posixFileSystem = PosixFileSystem();
+
+  group('windows metadata', () {
+    late String tmp;
+
+    setUp(() => tmp = createTemp('metadata'));
+
+    tearDown(() => deleteTemp(tmp));
+
+    group('isHidden', () {
+      test('false', () {
+        final path = '$tmp/file';
+        File(path).writeAsStringSync('Hello World');
+
+        final data = posixFileSystem.metadata(path);
+        expect(data.isHidden, isFalse);
+      });
+      test('false', () {
+        final path = '$tmp/file';
+        File(path).writeAsStringSync('Hello World');
+        using((arena) {
+          chflags(path.toNativeUtf8(), stdlibc.UF_HIDDEN);
+        });
+
+        final data = posixFileSystem.metadata(path);
+        expect(data.isHidden, isTrue);
+      });
+    });
+  });
+}

pkgs/io_file/test/metadata_test.dart

@@ -9,7 +9,9 @@ import 'dart:io';
 
 import 'package:io_file/io_file.dart';
 import 'package:test/test.dart';
+import 'package:win32/win32.dart' as win32;
 
+import 'errors.dart' as errors;
 import 'test_utils.dart';
 
 void main() {
@@ -26,13 +28,11 @@ void main() {
       expect(
         () => fileSystem.metadata('$tmp/file1'),
         throwsA(
-          isA<PathNotFoundException>()
-              .having((e) => e.message, 'message', 'metadata failed')
-              .having(
-                (e) => e.osError?.errorCode,
-                'errorCode',
-                2, // ENOENT, ERROR_FILE_NOT_FOUND
-              ),
+          isA<PathNotFoundException>().having(
+            (e) => e.osError?.errorCode,
+            'errorCode',
+            Platform.isWindows ? win32.ERROR_FILE_NOT_FOUND : errors.enoent,
+          ),
         ),
       );
     });
@@ -53,7 +53,7 @@ void main() {
         expect(data.isFile, isTrue);
         expect(data.isLink, isFalse);
       });
-      test('link', () {
+      test('file link', () {
         File('$tmp/file1').writeAsStringSync('Hello World');
         final path = '$tmp/link';
         Link(path).createSync('$tmp/file1');
@@ -63,13 +63,20 @@ void main() {
         expect(data.isFile, isFalse);
         expect(data.isLink, isTrue);
       });
+
+      test('directory link', () {
+        File('$tmp/file1').writeAsStringSync('Hello World');
+        final path = '$tmp/link';
+        Link(path).createSync('$tmp/dir');
+
+        final data = fileSystem.metadata(path);
+        expect(data.isDirectory, isFalse);
+        expect(data.isFile, isFalse);
+        expect(data.isLink, isTrue);
+      });
     });
 
     group('size', () {
-      test('directory', () {
-        final data = fileSystem.metadata(tmp);
-        expect(data.size, 0);
-      });
       test('empty file', () {
         final path = '$tmp/file1';
         File(path).writeAsStringSync('');
@@ -84,14 +91,6 @@ void main() {
         final data = fileSystem.metadata(path);
         expect(data.size, 12);
       });
-      test('link', () {
-        File('$tmp/file1').writeAsStringSync('Hello World');
-        final path = '$tmp/link';
-        Link(path).createSync('$tmp/file1');
-
-        final data = fileSystem.metadata(path);
-        expect(data.size, 0);
-      });
     });
   });
 }