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// 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));