merchant

Merchant backend to process payments, run by merchants
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do_fountain_withdraw.c (4786B)

      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/do_fountain_withdraw.c
     18  * @brief Implementation of the do_fountain_withdraw function for Postgres
     19  * @author Bohdan Potuzhnyi
     20  */
     21 #include "platform.h"
     22 #include <taler/taler_pq_lib.h>
     23 #include "merchant-database/do_fountain_withdraw.h"
     24 #include "helper.h"
     25 
     26 
     27 enum GNUNET_DB_QueryStatus
     28 TALER_MERCHANTDB_do_fountain_withdraw (
     29   struct TALER_MERCHANTDB_PostgresContext *pg,
     30   const char *instance_id,
     31   uint64_t fountain_serial,
     32   unsigned int num_entries,
     33   const uint64_t token_family_serials[static num_entries],
     34   const struct GNUNET_TIME_Timestamp slot_starts[static num_entries],
     35   const uint64_t num_requested[static num_entries],
     36   unsigned int *failed_index,
     37   bool *no_grant,
     38   bool *exceeded)
     39 {
     40   unsigned int order[GNUNET_NZL (num_entries)];
     41   uint64_t s_families[GNUNET_NZL (num_entries)];
     42   uint64_t s_slots[GNUNET_NZL (num_entries)];
     43   uint64_t s_counts[GNUNET_NZL (num_entries)];
     44   uint32_t sql_failed_index;
     45   struct GNUNET_PQ_QueryParam params[] = {
     46     GNUNET_PQ_query_param_uint64 (&fountain_serial),
     47     GNUNET_PQ_query_param_array_uint64 (num_entries,
     48                                         s_families,
     49                                         pg->conn),
     50     GNUNET_PQ_query_param_array_uint64 (num_entries,
     51                                         s_slots,
     52                                         pg->conn),
     53     GNUNET_PQ_query_param_array_uint64 (num_entries,
     54                                         s_counts,
     55                                         pg->conn),
     56     GNUNET_PQ_query_param_end
     57   };
     58   struct GNUNET_PQ_ResultSpec rs[] = {
     59     GNUNET_PQ_result_spec_uint32 ("out_failed_index",
     60                                   &sql_failed_index),
     61     GNUNET_PQ_result_spec_bool ("out_no_grant",
     62                                 no_grant),
     63     GNUNET_PQ_result_spec_bool ("out_exceeded",
     64                                 exceeded),
     65     GNUNET_PQ_result_spec_end
     66   };
     67   enum GNUNET_DB_QueryStatus qs;
     68 
     69   *failed_index = num_entries;
     70   *no_grant = false;
     71   *exceeded = false;
     72   /* Sort entries by (token_family_serial, slot_start) so that
     73      concurrent withdrawals acquire the counter row locks in a
     74      deterministic order and cannot deadlock.  Insertion sort: the
     75      number of entries is bounded by the request size cap. */
     76   for (unsigned int i = 0; i < num_entries; i++)
     77     order[i] = i;
     78   for (unsigned int i = 1; i < num_entries; i++)
     79   {
     80     unsigned int cur = order[i];
     81     unsigned int j = i;
     82 
     83     while ( (j > 0) &&
     84             ( (token_family_serials[order[j - 1]] >
     85                token_family_serials[cur]) ||
     86               ( (token_family_serials[order[j - 1]] ==
     87                  token_family_serials[cur]) &&
     88                 (slot_starts[order[j - 1]].abs_time.abs_value_us >
     89                  slot_starts[cur].abs_time.abs_value_us) ) ) )
     90     {
     91       order[j] = order[j - 1];
     92       j--;
     93     }
     94     order[j] = cur;
     95   }
     96   for (unsigned int i = 0; i < num_entries; i++)
     97   {
     98     s_families[i] = token_family_serials[order[i]];
     99     s_slots[i] = slot_starts[order[i]].abs_time.abs_value_us;
    100     s_counts[i] = num_requested[order[i]];
    101   }
    102   GNUNET_assert (NULL != pg->current_merchant_id);
    103   GNUNET_assert (0 == strcmp (instance_id,
    104                               pg->current_merchant_id));
    105   TMH_PQ_prepare_anon (pg,
    106                        "SELECT"
    107                        "  out_failed_index"
    108                        " ,out_no_grant"
    109                        " ,out_exceeded"
    110                        "  FROM merchant_do_fountain_withdraw"
    111                        " ($1, $2, $3, $4);");
    112   qs = GNUNET_PQ_eval_prepared_singleton_select (pg->conn,
    113                                                  "",
    114                                                  params,
    115                                                  rs);
    116   GNUNET_PQ_cleanup_query_params_closures (params);
    117   if (qs < 0)
    118     return qs;
    119   if (0 != sql_failed_index)
    120   {
    121     /* Map the 1-based index into the sorted arrays back to the
    122        caller's entry order. */
    123     GNUNET_assert (sql_failed_index <= num_entries);
    124     *failed_index = order[sql_failed_index - 1];
    125   }
    126   return qs;
    127 }