OpenFile

fn OpenFile(sub_path_w: []const u16, options: OpenFileOptions) OpenError!windows.HANDLE {
    if (std.mem.eql(u16, sub_path_w, &.{'.'}) and options.filter == .non_directory_only) {
        return error.IsDir;
    }
    if (std.mem.eql(u16, sub_path_w, &.{ '.', '.' }) and options.filter == .non_directory_only) {
        return error.IsDir;
    }

    var result: windows.HANDLE = undefined;

    const attr: windows.OBJECT.ATTRIBUTES = .{
        .RootDirectory = if (Dir.path.isAbsoluteWindowsWtf16(sub_path_w)) null else options.dir,
        .Attributes = .{ .INHERIT = if (options.sa) |sa| sa.bInheritHandle.toBool() else false },
        .ObjectName = @constCast(&windows.UNICODE_STRING.init(sub_path_w)),
        .SecurityDescriptor = if (options.sa) |ptr| ptr.lpSecurityDescriptor else null,
    };

    var iosb: windows.IO_STATUS_BLOCK = undefined;
    var attempt: u5 = 0;
    var syscall: Syscall = try .start();
    while (true) {
        switch (windows.ntdll.NtCreateFile(
            &result,
            options.access_mask,
            &attr,
            &iosb,
            null,
            .{ .NORMAL = true },
            options.share_access,
            options.creation,
            .{
                .DIRECTORY_FILE = options.filter == .dir_only,
                .NON_DIRECTORY_FILE = options.filter == .non_directory_only,
                .IO = .SYNCHRONOUS_NONALERT,
                .OPEN_REPARSE_POINT = !options.follow_symlinks,
            },
            null,
            0,
        )) {
            .SUCCESS => {
                syscall.finish();
                return result;
            },
            .CANCELLED => {
                try syscall.checkCancel();
                continue;
            },
            .SHARING_VIOLATION => {
                // This occurs if the file attempting to be opened is a running
                // executable. However, there's a kernel bug: the error may be
                // incorrectly returned for an indeterminate amount of time
                // after an executable file is closed. Here we work around the
                // kernel bug with retry attempts.
                syscall.finish();
                if (max_windows_kernel_bug_retries - attempt == 0) return error.FileBusy;
                try parking_sleep.sleep(.{ .duration = .{
                    .raw = .fromMilliseconds((@as(u32, 1) << attempt) >> 1),
                    .clock = .awake,
                } });
                attempt += 1;
                syscall = try .start();
                continue;
            },
            .DELETE_PENDING => {
                // This error means that there *was* a file in this location on
                // the file system, but it was deleted. However, the OS is not
                // finished with the deletion operation, and so this CreateFile
                // call has failed. There is not really a sane way to handle
                // this other than retrying the creation after the OS finishes
                // the deletion.
                syscall.finish();
                if (max_windows_kernel_bug_retries - attempt == 0) return error.FileBusy;
                try parking_sleep.sleep(.{ .duration = .{
                    .raw = .fromMilliseconds((@as(u32, 1) << attempt) >> 1),
                    .clock = .awake,
                } });
                attempt += 1;
                syscall = try .start();
                continue;
            },
            .OBJECT_NAME_INVALID => return syscall.fail(error.BadPathName),
            .OBJECT_NAME_NOT_FOUND => return syscall.fail(error.FileNotFound),
            .OBJECT_PATH_NOT_FOUND => return syscall.fail(error.FileNotFound),
            .BAD_NETWORK_PATH => return syscall.fail(error.NetworkNotFound), // \\server was not found
            .BAD_NETWORK_NAME => return syscall.fail(error.NetworkNotFound), // \\server was found but \\server\share wasn't
            .NO_MEDIA_IN_DEVICE => return syscall.fail(error.NoDevice),
            .ACCESS_DENIED => return syscall.fail(error.AccessDenied),
            .PIPE_BUSY => return syscall.fail(error.PipeBusy),
            .PIPE_NOT_AVAILABLE => return syscall.fail(error.NoDevice),
            .OBJECT_NAME_COLLISION => return syscall.fail(error.PathAlreadyExists),
            .FILE_IS_A_DIRECTORY => return syscall.fail(error.IsDir),
            .NOT_A_DIRECTORY => return syscall.fail(error.NotDir),
            .USER_MAPPED_FILE => return syscall.fail(error.AccessDenied),
            .VIRUS_INFECTED, .VIRUS_DELETED => return syscall.fail(error.AntivirusInterference),
            .INVALID_PARAMETER => |status| return syscall.ntstatusBug(status),
            .OBJECT_PATH_SYNTAX_BAD => |status| return syscall.ntstatusBug(status),
            .INVALID_HANDLE => |status| return syscall.ntstatusBug(status),
            else => |status| return syscall.unexpectedNtstatus(status),
        }
    }
}