exchange

Base system with REST service to issue digital coins, run by the payment service provider
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ensure_coin_known.c (5586B)


      1 /*
      2    This file is part of TALER
      3    Copyright (C) 2022 Taler Systems SA
      4 
      5    TALER is free software; you can redistribute it and/or modify it under the
      6    terms of the GNU General Public License as published by the Free Software
      7    Foundation; either version 3, or (at your option) any later version.
      8 
      9    TALER is distributed in the hope that it will be useful, but WITHOUT ANY
     10    WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
     11    A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
     12 
     13    You should have received a copy of the GNU General Public License along with
     14    TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
     15  */
     16 /**
     17  * @file exchangedb/ensure_coin_known.c
     18  * @brief Implementation of the ensure_coin_known function for Postgres
     19  * @author Christian Grothoff
     20  */
     21 #include "exchangedb_lib.h"
     22 #include "taler/taler_pq_lib.h"
     23 #include "exchange-database/ensure_coin_known.h"
     24 #include "helper.h"
     25 
     26 
     27 enum TALER_EXCHANGEDB_CoinKnownStatus
     28 TALER_EXCHANGEDB_ensure_coin_known (
     29   struct TALER_EXCHANGEDB_PostgresContext *pg,
     30   const struct TALER_CoinPublicInfo *coin,
     31   uint64_t *known_coin_id,
     32   struct TALER_DenominationHashP *denom_hash,
     33   struct TALER_AgeCommitmentHashP *h_age_commitment)
     34 {
     35   enum GNUNET_DB_QueryStatus qs;
     36   bool existed;
     37   bool no_denom_pub_hash;
     38   bool no_age_commitment_hash;
     39   struct GNUNET_PQ_QueryParam params[] = {
     40     GNUNET_PQ_query_param_auto_from_type (&coin->coin_pub),
     41     GNUNET_PQ_query_param_auto_from_type (&coin->denom_pub_hash),
     42     coin->no_age_commitment
     43     ? GNUNET_PQ_query_param_null ()
     44     : GNUNET_PQ_query_param_auto_from_type (&coin->h_age_commitment),
     45     TALER_PQ_query_param_denom_sig (&coin->denom_sig),
     46     GNUNET_PQ_query_param_end
     47   };
     48   struct GNUNET_PQ_ResultSpec rs[] = {
     49     GNUNET_PQ_result_spec_bool ("existed",
     50                                 &existed),
     51     GNUNET_PQ_result_spec_uint64 ("known_coin_id",
     52                                   known_coin_id),
     53     GNUNET_PQ_result_spec_allow_null (
     54       GNUNET_PQ_result_spec_auto_from_type ("denom_pub_hash",
     55                                             denom_hash),
     56       &no_denom_pub_hash),
     57     GNUNET_PQ_result_spec_allow_null (
     58       GNUNET_PQ_result_spec_auto_from_type ("age_commitment_hash",
     59                                             h_age_commitment),
     60       &no_age_commitment_hash),
     61     GNUNET_PQ_result_spec_end
     62   };
     63 
     64   /*
     65      See also:
     66      https://stackoverflow.com/questions/34708509/how-to-use-returning-with-on-conflict-in-postgresql/37543015#37543015
     67   */
     68   PREPARE (pg,
     69            "insert_known_coin",
     70            "WITH dd"
     71            "  (denominations_serial"
     72            "  ,coin"
     73            "  ) AS ("
     74            "    SELECT "
     75            "       denominations_serial"
     76            "      ,coin"
     77            "        FROM denominations"
     78            "        WHERE denom_pub_hash=$2"
     79            "  ), input_rows"
     80            "    (coin_pub) AS ("
     81            "      VALUES ($1::BYTEA)"
     82            "  ), ins AS ("
     83            "  INSERT INTO known_coins "
     84            "  (coin_pub"
     85            "  ,denominations_serial"
     86            "  ,age_commitment_hash"
     87            "  ,denom_sig"
     88            "  ,remaining"
     89            "  ) SELECT "
     90            "     $1"
     91            "    ,denominations_serial"
     92            "    ,$3"
     93            "    ,$4"
     94            "    ,coin"
     95            "  FROM dd"
     96            "  ON CONFLICT DO NOTHING" /* CONFLICT on (coin_pub) */
     97            "  RETURNING "
     98            "     known_coin_id"
     99            "  ) "
    100            "SELECT "
    101            "   FALSE AS existed"
    102            "  ,known_coin_id"
    103            "  ,NULL AS denom_pub_hash"
    104            "  ,NULL AS age_commitment_hash"
    105            "  FROM ins "
    106            "UNION ALL "
    107            "SELECT "
    108            "   TRUE AS existed"
    109            "  ,known_coin_id"
    110            "  ,denom_pub_hash"
    111            "  ,kc.age_commitment_hash"
    112            "  FROM input_rows"
    113            "  JOIN known_coins kc USING (coin_pub)"
    114            "  JOIN denominations USING (denominations_serial)"
    115            "  LIMIT 1");
    116   qs = GNUNET_PQ_eval_prepared_singleton_select (pg->conn,
    117                                                  "insert_known_coin",
    118                                                  params,
    119                                                  rs);
    120   switch (qs)
    121   {
    122   case GNUNET_DB_STATUS_HARD_ERROR:
    123     GNUNET_break (0);
    124     return TALER_EXCHANGEDB_CKS_HARD_FAIL;
    125   case GNUNET_DB_STATUS_SOFT_ERROR:
    126     return TALER_EXCHANGEDB_CKS_SOFT_FAIL;
    127   case GNUNET_DB_STATUS_SUCCESS_NO_RESULTS:
    128     GNUNET_break (0); /* should be impossible */
    129     return TALER_EXCHANGEDB_CKS_HARD_FAIL;
    130   case GNUNET_DB_STATUS_SUCCESS_ONE_RESULT:
    131     if (! existed)
    132       return TALER_EXCHANGEDB_CKS_ADDED;
    133     break; /* continued below */
    134   }
    135 
    136   if ( (! no_denom_pub_hash) &&
    137        (0 != GNUNET_memcmp (denom_hash,
    138                             &coin->denom_pub_hash)) )
    139   {
    140     GNUNET_break_op (0);
    141     return TALER_EXCHANGEDB_CKS_DENOM_CONFLICT;
    142   }
    143 
    144   if (no_age_commitment_hash != coin->no_age_commitment)
    145   {
    146     if (no_age_commitment_hash)
    147     {
    148       GNUNET_break_op (0);
    149       return TALER_EXCHANGEDB_CKS_AGE_CONFLICT_EXPECTED_NULL;
    150     }
    151     else
    152     {
    153       GNUNET_break_op (0);
    154       return TALER_EXCHANGEDB_CKS_AGE_CONFLICT_EXPECTED_NON_NULL;
    155     }
    156   }
    157   else if ( (! no_age_commitment_hash) &&
    158             (0 != GNUNET_memcmp (h_age_commitment,
    159                                  &coin->h_age_commitment)) )
    160   {
    161     GNUNET_break_op (0);
    162     return TALER_EXCHANGEDB_CKS_AGE_CONFLICT_VALUE_DIFFERS;
    163   }
    164 
    165   return TALER_EXCHANGEDB_CKS_PRESENT;
    166 }