dirOpenDirWindows

pub fn dirOpenDirWindows(
    dir: Dir,
    sub_path_w: []const u16,
    options: Dir.OpenOptions,
) Dir.OpenError!Dir {
    const w = windows;

    var io_status_block: w.IO_STATUS_BLOCK = undefined;
    var result: Dir = .{ .handle = undefined };

    const attr: w.OBJECT.ATTRIBUTES = .{
        .RootDirectory = if (Dir.path.isAbsoluteWindowsWtf16(sub_path_w)) null else dir.handle,
        .ObjectName = @constCast(&w.UNICODE_STRING.init(sub_path_w)),
    };

    const syscall: Syscall = try .start();
    while (true) switch (w.ntdll.NtCreateFile(
        &result.handle,
        // TODO remove some of these flags if options.access_sub_paths is false
        .{
            .SPECIFIC = .{ .FILE_DIRECTORY = .{
                .LIST = options.iterate,
                .READ_EA = true,
                .TRAVERSE = true,
                .READ_ATTRIBUTES = true,
            } },
            .STANDARD = .{
                .RIGHTS = .READ,
                .SYNCHRONIZE = true,
            },
        },
        &attr,
        &io_status_block,
        null,
        .{ .NORMAL = true },
        .VALID_FLAGS,
        .OPEN,
        .{
            .DIRECTORY_FILE = true,
            .IO = .SYNCHRONOUS_NONALERT,
            .OPEN_FOR_BACKUP_INTENT = true,
            .OPEN_REPARSE_POINT = !options.follow_symlinks,
        },
        null,
        0,
    )) {
        .SUCCESS => {
            syscall.finish();
            return result;
        },
        .CANCELLED => {
            try syscall.checkCancel();
            continue;
        },
        .OBJECT_NAME_INVALID => return syscall.fail(error.BadPathName),
        .OBJECT_NAME_NOT_FOUND => return syscall.fail(error.FileNotFound),
        .OBJECT_NAME_COLLISION => |err| return w.statusBug(err),
        .OBJECT_PATH_NOT_FOUND => return syscall.fail(error.FileNotFound),
        .NOT_A_DIRECTORY => return syscall.fail(error.NotDir),
        // This can happen if the directory has 'List folder contents' permission set to 'Deny'
        // and the directory is trying to be opened for iteration.
        .ACCESS_DENIED => return syscall.fail(error.AccessDenied),
        .INVALID_PARAMETER => |err| return syscall.ntstatusBug(err),
        else => |rc| return syscall.unexpectedNtstatus(rc),
    };
}