exchange/src/exchangedb/exchangedb_transactions.c

/*
  This file is part of TALER
  Copyright (C) 2017-2020 Taler Systems SA

  TALER is free software; you can redistribute it and/or modify it under the
  terms of the GNU General Public License as published by the Free Software
  Foundation; either version 3, or (at your option) any later version.

  TALER is distributed in the hope that it will be useful, but WITHOUT ANY
  WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
  A PARTICULAR PURPOSE.  See the GNU General Public License for more details.

  You should have received a copy of the GNU General Public License along with
  TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
*/
/**
 * @file exchangedb/exchangedb_transactions.c
 * @brief Logic to compute transaction totals of a transaction list for a coin
 * @author Christian Grothoff
 */
#include "platform.h"
#include "taler_exchangedb_lib.h"


/**
 * Calculate the total value of all transactions performed.
 * Stores @a off plus the cost of all transactions in @a tl
 * in @a ret.
 *
 * @param tl transaction list to process
 * @param off offset to use as the starting value
 * @param[out] ret where the resulting total is to be stored
 * @return #GNUNET_OK on success, #GNUNET_SYSERR on errors
 */
int
TALER_EXCHANGEDB_calculate_transaction_list_totals (struct
                                                    TALER_EXCHANGEDB_TransactionList
                                                    *tl,
                                                    const struct
                                                    TALER_Amount *off,
                                                    struct TALER_Amount *ret)
{
  struct TALER_Amount spent = *off;
  struct TALER_Amount refunded;

  GNUNET_assert (GNUNET_OK ==
                 TALER_amount_get_zero (spent.currency,
                                        &refunded));
  for (struct TALER_EXCHANGEDB_TransactionList *pos = tl; NULL != pos; pos =
         pos->next)
  {
    switch (pos->type)
    {
    case TALER_EXCHANGEDB_TT_DEPOSIT:
      /* spent += pos->amount_with_fee */
      if (GNUNET_OK !=
          TALER_amount_add (&spent,
                            &spent,
                            &pos->details.deposit->amount_with_fee))
      {
        GNUNET_break (0);
        return GNUNET_SYSERR;
      }
      break;
    case TALER_EXCHANGEDB_TT_REFRESH_MELT:
      /* spent += pos->amount_with_fee */
      if (GNUNET_OK !=
          TALER_amount_add (&spent,
                            &spent,
                            &pos->details.melt->session.amount_with_fee))
      {
        GNUNET_break (0);
        return GNUNET_SYSERR;
      }
      break;
    case TALER_EXCHANGEDB_TT_REFUND:
      /* refunded += pos->refund_amount - pos->refund_fee */
      if (GNUNET_OK !=
          TALER_amount_add (&refunded,
                            &refunded,
                            &pos->details.refund->refund_amount))
      {
        GNUNET_break (0);
        return GNUNET_SYSERR;
      }
      if (GNUNET_OK !=
          TALER_amount_subtract (&refunded,
                                 &refunded,
                                 &pos->details.refund->refund_fee))
      {
        GNUNET_break (0);
        return GNUNET_SYSERR;
      }
      break;
    case TALER_EXCHANGEDB_TT_OLD_COIN_PAYBACK:
      /* refunded += pos->value */
      if (GNUNET_OK !=
          TALER_amount_add (&refunded,
                            &refunded,
                            &pos->details.old_coin_payback->value))
      {
        GNUNET_break (0);
        return GNUNET_SYSERR;
      }
      break;
    case TALER_EXCHANGEDB_TT_PAYBACK:
      /* spent += pos->value */
      if (GNUNET_OK !=
          TALER_amount_add (&spent,
                            &spent,
                            &pos->details.payback->value))
      {
        GNUNET_break (0);
        return GNUNET_SYSERR;
      }
      break;
    case TALER_EXCHANGEDB_TT_PAYBACK_REFRESH:
      /* spent += pos->value */
      if (GNUNET_OK !=
          TALER_amount_add (&spent,
                            &spent,
                            &pos->details.payback_refresh->value))
      {
        GNUNET_break (0);
        return GNUNET_SYSERR;
      }
      break;
    }
  }
  /* spent = spent - refunded */
  if (GNUNET_SYSERR ==
      TALER_amount_subtract (&spent,
                             &spent,
                             &refunded))
  {
    GNUNET_break (0);
    return GNUNET_SYSERR;
  }

  *ret = spent;
  return GNUNET_OK;
}