type
  TUserInfo = class
  strict private
    FSIDStr: string;
    FADsUser: IADsUser;
  strict private
    function GetADsUser: IADsUser;
  public
    constructor Create(const ASIDStr: string);
  end;

constructor TUserInfo.Create(const ASIDStr: string);
begin
  inherited Create;
  FSIDStr := ASIDStr;
end;

function TUserInfo.GetADsUser: IADsUser;
begin
  if FADsUser = nil then begin
    OleCheck(ADsGetObject(
      PChar(Format('LDAP://<SID=%s>', [FSIDStr])),
      IID_IADsUser,
      FADsUser
    ));
    FADsUser.GetInfo;
  end;
  Result := FADsUser;
end;

type
  TUDFUserInfo = class(TUserInfo)
  public
    constructor Create(const ASIDStr: string);
    destructor Destroy; override;
  end;

constructor TUDFUserInfo.Create(const ASIDStr: string);
begin
  inherited Create(ASIDStr);
  Coinitialize(nil);
end;

destructor TUDFUserInfo.Destroy;
begin
  СoUninitialize;
  inherited Destroy;
end;

destructor TUserInfo.Destroy;
begin
  FADsUser := nil;
  inherited Destroy;
end;

destructor TUDFUserInfo.Destroy;
begin
  inherited Destroy;
  СoUninitialize;
end;