exchange

Base system with REST service to issue digital coins, run by the payment service provider
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exchange_do_refresh.sql (4886B)


      1 --
      2 -- This file is part of TALER
      3 -- Copyright (C) 2025 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 -- @author Özgür Kesim
     17 
     18 DROP FUNCTION IF EXISTS exchange_do_refresh;
     19 
     20 CREATE FUNCTION exchange_do_refresh(
     21   IN in_rc BYTEA,
     22   IN in_now INT8,
     23   IN in_refresh_seed BYTEA,
     24   IN in_transfer_pubs BYTEA[],
     25   IN in_planchets_h BYTEA,
     26   IN in_amount_with_fee taler_amount,
     27   IN in_blinding_seed BYTEA,
     28   IN in_cs_r_values BYTEA[],
     29   IN in_cs_r_choices INT8,
     30   IN in_selected_h BYTEA,
     31   IN in_denom_sigs BYTEA[],
     32   IN in_denom_serials INT8[],
     33   IN in_old_coin_pub BYTEA,
     34   IN in_old_coin_sig BYTEA,
     35   IN in_noreveal_index INT4,
     36   IN in_zombie_required BOOLEAN,
     37   OUT out_coin_found BOOLEAN,
     38   OUT out_balance_ok BOOLEAN,
     39   OUT out_zombie_bad BOOLEAN,
     40   OUT out_nonce_reuse BOOLEAN,
     41   OUT out_idempotent BOOLEAN,
     42   OUT out_noreveal_index INT4,
     43   OUT out_coin_balance taler_amount)
     44 LANGUAGE plpgsql
     45 AS $$
     46 DECLARE
     47   known_coin RECORD;
     48   difference RECORD;
     49 BEGIN
     50 -- Shards: INSERT refresh (by rc)
     51 -- (rare:) SELECT refresh (by old_coin_pub) -- crosses shards!
     52 -- (rare:) SELECT refresh_revealed_coins (by refresh_id)
     53 -- (rare:) PERFORM recoup_refresh (by rrc_serial) -- crosses shards!
     54 --         UPDATE known_coins (by coin_pub)
     55 
     56 -- First, find old coin
     57 SELECT known_coin_id
     58      ,remaining
     59   INTO known_coin
     60   FROM known_coins
     61   WHERE coin_pub = in_old_coin_pub;
     62 
     63 IF NOT FOUND
     64 THEN
     65   out_coin_found = FALSE;
     66   out_balance_ok = TRUE;
     67   out_zombie_bad = FALSE;
     68   out_nonce_reuse = FALSE;
     69   out_idempotent = FALSE;
     70   out_noreveal_index = -1 ;
     71   out_coin_balance.val = 0;
     72   out_coin_balance.frac = 0;
     73   RETURN;
     74 END IF;
     75 
     76 out_coin_found = TRUE;
     77 out_coin_balance = known_coin.remaining;
     78 
     79 -- Next, check for idempotency
     80 SELECT TRUE, noreveal_index
     81 INTO out_idempotent, out_noreveal_index
     82 FROM exchange.refresh
     83 WHERE rc=in_rc;
     84 
     85 IF out_idempotent
     86 THEN
     87   -- out_idempotent is set
     88   -- out_noreveal_index is set
     89   -- out_coin_found is set
     90   -- out_coin_balance is set
     91   out_balance_ok = TRUE;
     92   out_zombie_bad = FALSE; -- zombie is OK
     93   out_nonce_reuse = FALSE;
     94 RETURN;
     95 END IF;
     96 
     97 out_idempotent = FALSE;
     98 out_noreveal_index = in_noreveal_index;
     99 
    100 -- Ensure the uniqueness of the blinding_seed
    101 IF in_blinding_seed IS NOT NULL
    102 THEN
    103   INSERT INTO unique_refresh_blinding_seed
    104     (blinding_seed)
    105   VALUES
    106     (in_blinding_seed)
    107   ON CONFLICT DO NOTHING;
    108 
    109   IF NOT FOUND
    110   THEN
    111       out_nonce_reuse = TRUE;
    112       out_balance_ok = TRUE;
    113       out_zombie_bad = FALSE; -- zombie is OK
    114       RETURN;
    115   END IF;
    116 END IF;
    117 
    118 out_nonce_reuse = FALSE;
    119 
    120 INSERT INTO exchange.refresh
    121   (rc
    122   ,execution_date
    123   ,old_coin_pub
    124   ,old_coin_sig
    125   ,planchets_h
    126   ,transfer_pubs
    127   ,amount_with_fee
    128   ,noreveal_index
    129   ,refresh_seed
    130   ,blinding_seed
    131   ,cs_r_values
    132   ,cs_r_choices
    133   ,selected_h
    134   ,denom_sigs
    135   ,denom_serials
    136   )
    137   VALUES
    138   (in_rc
    139   ,in_now
    140   ,in_old_coin_pub
    141   ,in_old_coin_sig
    142   ,in_planchets_h
    143   ,in_transfer_pubs
    144   ,in_amount_with_fee
    145   ,in_noreveal_index
    146   ,in_refresh_seed
    147   ,in_blinding_seed
    148   ,in_cs_r_values
    149   ,in_cs_r_choices
    150   ,in_selected_h
    151   ,in_denom_sigs
    152   ,in_denom_serials
    153   )
    154   ON CONFLICT DO NOTHING;
    155 
    156 IF NOT FOUND
    157 THEN
    158   RAISE EXCEPTION 'Conflict in refresh despite idempotency check for rc(%)!', rc;
    159   RETURN;
    160 END IF;
    161 
    162 IF in_zombie_required
    163 THEN
    164   -- Check if this coin was part of a refresh
    165   -- operation that was subsequently involved
    166   -- in a recoup operation.  We begin by all
    167   -- refresh operations our coin was involved
    168   -- with, then find all associated reveal
    169   -- operations, and then see if any of these
    170   -- reveal operations was involved in a recoup.
    171   PERFORM
    172    FROM recoup_refresh
    173    WHERE refresh_id IN
    174       (SELECT refresh_id
    175        FROM refresh
    176        WHERE old_coin_pub=in_old_coin_pub);
    177   IF NOT FOUND
    178   THEN
    179     out_zombie_bad=TRUE;
    180     out_balance_ok=FALSE;
    181     RETURN;
    182   END IF;
    183 END IF;
    184 
    185 out_zombie_bad=FALSE; -- zombie is OK
    186 
    187 -- Check coin balance is sufficient.
    188 SELECT *
    189 INTO difference
    190 FROM amount_left_minus_right(out_coin_balance
    191                             ,in_amount_with_fee);
    192 
    193 out_balance_ok = difference.ok;
    194 
    195 IF NOT out_balance_ok
    196 THEN
    197   RETURN;
    198 END IF;
    199 
    200 out_coin_balance = difference.diff;
    201 
    202 -- Check and update balance of the coin.
    203 UPDATE known_coins
    204   SET
    205     remaining = out_coin_balance
    206   WHERE
    207     known_coin_id = known_coin.known_coin_id;
    208 
    209 END $$;