TerraOceanPlugin/GoBot/db_invite.go

package main

import "errors"

var errInviteUsed = errors.New("db: the requested invite has already been used")

func getInviteOwner(inviteCode string) (string, error) {
	rows, err := db.Query("SELECT owner, used FROM invite WHERE code=?", inviteCode)
	if err != nil {
		return "", err
	}
	defer rows.Close()
	if rows.Next() {
		var owner string
		var used bool
		err := rows.Scan(&owner, &used)
		if err != nil {
			return "", err
		}
		if used {
			return "", errInviteUsed
		}
		return owner, nil
	}
	return "", errNotFound
}

func setInviteOwner(inviteCode, owner string) error {
	_, err := getInviteOwner(inviteCode)
	if err == nil {
		return errAlreadyExists
	}
	if err != errNotFound {
		return err
	}
	_, err = db.Exec("INSERT INTO invite(code, owner, used) VALUES(?,?,?)", inviteCode, owner, false)
	return err
}

func useInvite(inviteCode string) error {
	owner, err := getInviteOwner(inviteCode)
	if err != nil {
		return err
	}
	_, err = db.Exec("REPLACE INTO invite(code, owner, used) VALUES(?,?,?)", inviteCode, owner, true)
	return err
}