merchant

Merchant backend to process payments, run by merchants
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iterate_fountains.c (4451B)

      1 /*
      2    This file is part of TALER
      3    Copyright (C) 2026 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/backenddb/iterate_fountains.c
     18  * @brief Implementation of the iterate_fountains function for Postgres
     19  * @author Bohdan Potuzhnyi
     20  */
     21 #include "platform.h"
     22 #include <taler/taler_pq_lib.h>
     23 #include "merchant-database/iterate_fountains.h"
     24 #include "helper.h"
     25 
     26 
     27 /**
     28  * Context used for TALER_MERCHANTDB_iterate_fountains().
     29  */
     30 struct LookupFountainsContext
     31 {
     32   /**
     33    * Function to call with the results.
     34    */
     35   TALER_MERCHANTDB_FountainsCallback cb;
     36 
     37   /**
     38    * Closure for @a cb.
     39    */
     40   void *cb_cls;
     41 
     42   /**
     43    * Did database result extraction fail?
     44    */
     45   bool extract_failed;
     46 };
     47 
     48 
     49 /**
     50  * Function to be called with the results of a SELECT statement
     51  * that has returned @a num_results results about fountains.
     52  *
     53  * @param[in,out] cls of type `struct LookupFountainsContext *`
     54  * @param result the postgres result
     55  * @param num_results the number of results in @a result
     56  */
     57 static void
     58 lookup_fountains_cb (void *cls,
     59                      PGresult *result,
     60                      unsigned int num_results)
     61 {
     62   struct LookupFountainsContext *lfc = cls;
     63 
     64   for (unsigned int i = 0; i < num_results; i++)
     65   {
     66     uint64_t fountain_serial;
     67     char *fountain_id;
     68     char *description;
     69     struct GNUNET_PQ_ResultSpec rs[] = {
     70       GNUNET_PQ_result_spec_uint64 ("fountain_serial",
     71                                     &fountain_serial),
     72       GNUNET_PQ_result_spec_string ("fountain_id",
     73                                     &fountain_id),
     74       GNUNET_PQ_result_spec_string ("description",
     75                                     &description),
     76       GNUNET_PQ_result_spec_end
     77     };
     78 
     79     if (GNUNET_OK !=
     80         GNUNET_PQ_extract_result (result,
     81                                   rs,
     82                                   i))
     83     {
     84       GNUNET_break (0);
     85       lfc->extract_failed = true;
     86       return;
     87     }
     88     lfc->cb (lfc->cb_cls,
     89              fountain_serial,
     90              fountain_id,
     91              description);
     92     GNUNET_PQ_cleanup_result (rs);
     93   }
     94 }
     95 
     96 
     97 enum GNUNET_DB_QueryStatus
     98 TALER_MERCHANTDB_iterate_fountains (
     99   struct TALER_MERCHANTDB_PostgresContext *pg,
    100   const char *instance_id,
    101   uint64_t offset,
    102   int64_t limit,
    103   TALER_MERCHANTDB_FountainsCallback cb,
    104   void *cb_cls)
    105 {
    106   uint64_t plimit = GNUNET_MIN ((uint64_t) 100,
    107                                 TALER_MERCHANTDB_abs_limit (limit));
    108   struct LookupFountainsContext lfc = {
    109     .cb = cb,
    110     .cb_cls = cb_cls,
    111     .extract_failed = false,
    112   };
    113   struct GNUNET_PQ_QueryParam params[] = {
    114     GNUNET_PQ_query_param_uint64 (&offset),
    115     GNUNET_PQ_query_param_uint64 (&plimit),
    116     GNUNET_PQ_query_param_end
    117   };
    118   enum GNUNET_DB_QueryStatus qs;
    119 
    120   GNUNET_assert (NULL != pg->current_merchant_id);
    121   GNUNET_assert (0 == strcmp (instance_id,
    122                               pg->current_merchant_id));
    123   if (offset > INT64_MAX)
    124     return GNUNET_DB_STATUS_HARD_ERROR;
    125   TMH_PQ_prepare_anon (pg,
    126                        limit >= 0
    127                        ? "SELECT fountain_serial,fountain_id,description"
    128                        " FROM merchant_fountains"
    129                        " WHERE fountain_serial > $1"
    130                        " ORDER BY fountain_serial ASC LIMIT $2"
    131                        : "SELECT fountain_serial,fountain_id,description"
    132                        " FROM merchant_fountains"
    133                        " WHERE fountain_serial < $1"
    134                        " ORDER BY fountain_serial DESC LIMIT $2");
    135   qs = GNUNET_PQ_eval_prepared_multi_select (pg->conn,
    136                                              "",
    137                                              params,
    138                                              &lookup_fountains_cb,
    139                                              &lfc);
    140   if (lfc.extract_failed)
    141     return GNUNET_DB_STATUS_HARD_ERROR;
    142   return qs;
    143 }