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Base system with REST service to issue digital coins, run by the payment service provider
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get_balance.c (5016B)


      1 /*
      2    This file is part of TALER
      3    Copyright (C) 2024 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 src/auditordb/get_balance.c
     18  * @brief Implementation of the get_balance function for Postgres
     19  * @author Christian Grothoff
     20  */
     21 #include "taler/taler_error_codes.h"
     22 #include "taler/taler_pq_lib.h"
     23 #include "auditor-database/get_balance.h"
     24 #include "pg_helper.h"
     25 
     26 
     27 /**
     28  * Closure for #balance_cb().
     29  */
     30 struct BalanceContext
     31 {
     32 
     33   /**
     34    * Where to store results.
     35    */
     36   struct TALER_Amount **dst;
     37 
     38   /**
     39    * Offset in @e dst.
     40    */
     41   unsigned int off;
     42 
     43   /**
     44    * Length of array at @e dst.
     45    */
     46   unsigned int len;
     47 
     48   /**
     49    * Plugin context.
     50    */
     51   struct TALER_AUDITORDB_PostgresContext *pg;
     52 
     53   /**
     54    * Set to true on failure.
     55    */
     56   bool failure;
     57 
     58 };
     59 
     60 
     61 /**
     62  * Helper function for #TALER_AUDITORDB_get_balance().
     63  * To be called with the results of a SELECT statement
     64  * that has returned @a num_results results.
     65  *
     66  * @param cls closure of type `struct BalanceContext *`
     67  * @param result the postgres result
     68  * @param num_results the number of results in @a result
     69  */
     70 static void
     71 balance_cb (void *cls,
     72             PGresult *result,
     73             unsigned int num_results)
     74 {
     75   struct BalanceContext *ctx = cls;
     76   struct TALER_AUDITORDB_PostgresContext *pg = ctx->pg;
     77 
     78   GNUNET_assert (num_results <= ctx->len);
     79   for (unsigned int i = 0; i < num_results; i++)
     80   {
     81     bool is_missing;
     82     struct GNUNET_PQ_ResultSpec rs[] = {
     83       GNUNET_PQ_result_spec_allow_null (
     84         TALER_PQ_result_spec_amount ("balance",
     85                                      pg->currency,
     86                                      ctx->dst[i]),
     87         &is_missing),
     88       GNUNET_PQ_result_spec_end
     89     };
     90 
     91     if (GNUNET_OK !=
     92         GNUNET_PQ_extract_result (result,
     93                                   rs,
     94                                   i))
     95     {
     96       GNUNET_break (0);
     97       ctx->failure = true;
     98       return;
     99     }
    100     if (is_missing)
    101     {
    102       GNUNET_assert (GNUNET_OK ==
    103                      TALER_amount_set_zero (pg->currency,
    104                                             ctx->dst[i]));
    105     }
    106     ctx->off++;
    107   }
    108 }
    109 
    110 
    111 enum GNUNET_DB_QueryStatus
    112 TALER_AUDITORDB_get_balance (
    113   struct TALER_AUDITORDB_PostgresContext *pg,
    114   const char *balance_key,
    115   struct TALER_Amount *balance_value,
    116   ...)
    117 {
    118   unsigned int cnt = 1;
    119   va_list ap;
    120 
    121   GNUNET_assert (GNUNET_OK ==
    122                  TALER_amount_set_zero (pg->currency,
    123                                         balance_value));
    124   va_start (ap,
    125             balance_value);
    126   while (NULL != va_arg (ap,
    127                          const char *))
    128   {
    129     struct TALER_Amount *dst;
    130 
    131     cnt++;
    132     dst = va_arg (ap,
    133                   struct TALER_Amount *);
    134     GNUNET_assert (GNUNET_OK ==
    135                    TALER_amount_set_zero (pg->currency,
    136                                           dst));
    137   }
    138   va_end (ap);
    139   {
    140     const char *keys[cnt];
    141     struct TALER_Amount *dsts[cnt];
    142     unsigned int off = 1;
    143     struct GNUNET_PQ_QueryParam params[] = {
    144       GNUNET_PQ_query_param_array_ptrs_string (cnt,
    145                                                keys,
    146                                                pg->conn),
    147       GNUNET_PQ_query_param_end
    148     };
    149     struct BalanceContext ctx = {
    150       .dst = dsts,
    151       .len = cnt,
    152       .pg = pg
    153     };
    154     enum GNUNET_DB_QueryStatus qs;
    155 
    156     keys[0] = balance_key;
    157     dsts[0] = balance_value;
    158     va_start (ap,
    159               balance_value);
    160     while (off < cnt)
    161     {
    162       keys[off] = va_arg (ap,
    163                           const char *);
    164       dsts[off] = va_arg (ap,
    165                           struct TALER_Amount *);
    166       off++;
    167     }
    168     GNUNET_assert (NULL == va_arg (ap,
    169                                    const char *));
    170     va_end (ap);
    171 
    172     PREPARE (pg,
    173              "get_balance",
    174              "SELECT "
    175              " auditor_do_get_balance AS balance"
    176              " FROM auditor_do_get_balance "
    177              "($1);");
    178     qs = GNUNET_PQ_eval_prepared_multi_select (pg->conn,
    179                                                "get_balance",
    180                                                params,
    181                                                &balance_cb,
    182                                                &ctx);
    183     GNUNET_PQ_cleanup_query_params_closures (params);
    184     if (ctx.failure)
    185       return GNUNET_DB_STATUS_HARD_ERROR;
    186     if (qs < 0)
    187       return qs;
    188     GNUNET_assert (qs == ctx.off);
    189     return qs;
    190   }
    191 }