| // Copyright 2017, 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. |
| |
| import 'dart:async'; |
| import 'dart:io'; |
| |
| /// What type of permission is granted to a file based on file permission roles. |
| enum _FilePermission { |
| execute, |
| // Although these two values are unused, their positions in the enum are |
| // meaningful. |
| write, // ignore: unused_field |
| read, // ignore: unused_field |
| setGid, |
| setUid, |
| sticky, |
| } |
| |
| /// What type of role is assigned to a file. |
| enum _FilePermissionRole { |
| world, |
| group, |
| user, |
| } |
| |
| /// Returns whether file [stat] has [permission] for a [role] type. |
| bool _hasPermission( |
| FileStat stat, |
| _FilePermission permission, { |
| _FilePermissionRole role = _FilePermissionRole.world, |
| }) { |
| final index = _permissionBitIndex(permission, role); |
| return (stat.mode & (1 << index)) != 0; |
| } |
| |
| int _permissionBitIndex(_FilePermission permission, _FilePermissionRole role) => |
| switch (permission) { |
| _FilePermission.setUid => 11, |
| _FilePermission.setGid => 10, |
| _FilePermission.sticky => 9, |
| _ => (role.index * 3) + permission.index |
| }; |
| |
| /// Returns whether [path] is considered an executable file on this OS. |
| /// |
| /// May optionally define how to implement [getStat] or whether to execute based |
| /// on whether this is the windows platform ([isWindows]) - if not set it is |
| /// automatically extracted from `dart:io#Platform`. |
| /// |
| /// **NOTE**: On windows this always returns `true`. |
| FutureOr<bool> isExecutable( |
| String path, { |
| bool? isWindows, |
| FutureOr<FileStat> Function(String path) getStat = FileStat.stat, |
| }) { |
| // Windows has no concept of executable. |
| if (isWindows ?? Platform.isWindows) return true; |
| final stat = getStat(path); |
| if (stat is FileStat) { |
| return _isExecutable(stat); |
| } |
| return stat.then(_isExecutable); |
| } |
| |
| bool _isExecutable(FileStat stat) => |
| stat.type == FileSystemEntityType.file && |
| _FilePermissionRole.values.any( |
| (role) => _hasPermission(stat, _FilePermission.execute, role: role)); |