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--
-- This file is part of TALER
-- Copyright (C) 2014--2022 Taler Systems SA
--
-- TALER is free software; you can redistribute it and/or modify it under the
-- terms of the GNU General Public License as published by the Free Software
-- Foundation; either version 3, or (at your option) any later version.
--
-- TALER is distributed in the hope that it will be useful, but WITHOUT ANY
-- WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
-- A PARTICULAR PURPOSE. See the GNU General Public License for more details.
--
-- You should have received a copy of the GNU General Public License along with
-- TALER; see the file COPYING. If not, see <http://www.gnu.org/licenses/>
--
CREATE OR REPLACE FUNCTION exchange_do_history_request(
IN in_reserve_pub BYTEA,
IN in_reserve_sig BYTEA,
IN in_request_timestamp INT8,
IN in_history_fee taler_amount,
OUT out_balance_ok BOOLEAN,
OUT out_idempotent BOOLEAN)
LANGUAGE plpgsql
AS $$
DECLARE
reserve RECORD;
balance taler_amount;
new_balance taler_amount;
BEGIN
-- Insert and check for idempotency.
INSERT INTO exchange.history_requests
(reserve_pub
,request_timestamp
,reserve_sig
,history_fee)
VALUES
(in_reserve_pub
,in_request_timestamp
,in_reserve_sig
,in_history_fee)
ON CONFLICT DO NOTHING;
IF NOT FOUND
THEN
out_balance_ok=TRUE;
out_idempotent=TRUE;
RETURN;
END IF;
out_idempotent=FALSE;
SELECT *
INTO reserve
FROM exchange.reserves
WHERE reserve_pub=in_reserve_pub;
IF NOT FOUND
THEN
-- Reserve does not exist, we treat it the same here
-- as balance insufficient.
out_balance_ok=FALSE;
RETURN;
END IF;
balance = reserve.current_balance;
-- check balance
IF ( (balance.val <= in_history_fee.val) AND
( (balance.frac < in_history_fee.frac) OR
(balance.val < in_history_fee.val) ) )
THEN
out_balance_ok=FALSE;
RETURN;
END IF;
new_balance.frac=balance.frac-in_history_fee.frac
+ CASE
WHEN balance.frac < in_history_fee.frac
THEN 100000000
ELSE 0
END;
new_balance.val=balance.val-in_history_fee.val
- CASE
WHEN balance.frac < in_history_fee.frac
THEN 1
ELSE 0
END;
-- Update reserve balance.
UPDATE exchange.reserves
SET current_balance=new_balance
WHERE reserve_pub=in_reserve_pub;
ASSERT FOUND, 'reserve suddenly disappeared';
out_balance_ok=TRUE;
END $$;
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