modifypkg2.cpp

 [[eosio::action]] void modifypkg2(uint64_t id, package newpackage) {
    require_auth(newpackage.provider);

    packages_t packages(_self, _self.value);
    auto idxKey = package::_by_package_service_provider(
        newpackage.package_id, newpackage.service, newpackage.provider);
    auto cidx = packages.get_index<"bypkg"_n>();
    auto existing = cidx.find(idxKey);

    eosio::check(existing != cidx.end(), "does not exist");
    eosio::check(newpackage.quota.symbol == DAPPSERVICES_QUOTA_SYMBOL, "wrong symbol");

    packages.modify(existing, newpackage.provider, [&](package &r) {
      r.provider = newpackage.provider;
      r.service = newpackage.service;
      r.package_id = newpackage.package_id;
      r.quota = newpackage.quota;
      r.min_stake_quantity = newpackage.min_stake_quantity;
      r.min_unstake_period = newpackage.min_unstake_period;
      r.package_json_uri = newpackage.package_json_uri;
      r.api_endpoint = newpackage.api_endpoint;      
      r.package_period = newpackage.package_period;
    });
  }