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-- Everything in one big transaction
-- BEGIN;
-- Check patch versioning is in place.
-- SELECT _v.register_patch('exchange-000x', NULL, NULL);
CREATE OR REPLACE FUNCTION exchange_do_melt(
IN denom_val INT8, -- value of the denomination of the coin
IN denom_frac INT4, -- value of the denomination of the coin
IN amount_val INT8, -- requested melt amount (with fee)
IN amount_frac INT4, -- requested melt amount (with fee)
IN in_rc BYTEA, -- refresh session hash
IN in_coin_pub BYTEA, -- coin public key
IN coin_sig BYTEA, -- melt signature
IN in_noreveal_index INT4, -- suggested random noreveal index
IN zombie_required BOOLEAN, -- do we need a zombie coin?
OUT out_noreval_index INT4, -- noreveal index to actually use
OUT balance_ok BOOLEAN, -- balance satisfied?
OUT zombie_ok BOOLEAN, -- zombie satisfied?
OUT melt_ok BOOLEAN) -- everything OK?
LANGUAGE plpgsql
AS $$
DECLARE
coin_uuid INT8; -- known_coin_id of coin_pub
DECLARE
tmp_val INT8; -- temporary result
DECLARE
tmp_frac INT8; -- temporary result
DECLARE
spent_val INT8; -- how much of coin was spent?
DECLARE
spent_frac INT8; -- how much of coin was spent?
DECLARE
unspent_val INT8; -- how much of coin was refunded?
DECLARE
unspent_frac INT8; -- how much of coin was refunded?
BEGIN
SELECT known_coin_id INTO coin_uuid
FROM known_coins
WHERE coin_pub=in_coin_pub;
IF NOT FOUND
THEN
-- coin unknown, should be impossible!
out_noreveal_index=-1;
balance_ok=FALSE;
zombie_ok=FALSE;
melt_ok=FALSE;
ASSERT false, 'coin unknown';
RETURN;
END IF;
-- We optimistically insert, and then on conflict declare
-- the query successful due to idempotency.
INSERT INTO refresh_commitments
(rc
,old_known_coin_id
,old_coin_sig
,amount_with_fee_val
,amount_with_fee_frac
,noreveal_index)
VALUES
(in_rc
,coin_uuid
,coin_sig
,amount_val
,amount_frac
,in_noreveal_index)
ON CONFLICT DO NOTHING;
IF FOUND
THEN
-- already melted, get noreveal_index
SELECT noreveal_index INTO out_noreveal_index
FROM refresh_commitments
WHERE rc=in_rc ;
balance_ok=TRUE;
zombie_ok=TRUE;
melt_ok=TRUE;
RETURN;
END IF;
-- Need to check for sufficient balance...
spent_val = 0;
spent_frac = 0;
unspent_val = 0;
unspent_frac = 0;
SELECT
SUM(amount_with_fee_val) -- overflow here is not plausible
,SUM(CAST(amount_with_fee_frac AS INT8)) -- compute using 64 bits
INTO
tmp_val
,tmp_frac
FROM deposits
WHERE known_coin_id=coin_uuid;
spent_val = spent_val + tmp_val;
spent_frac = spent_frac + tmp_frac;
SELECT
SUM(amount_with_fee_val) -- overflow here is not plausible
,SUM(CAST(amount_with_fee_frac AS INT8)) -- compute using 64 bits
INTO
tmp_val
,tmp_frac
FROM refresh_commitments
WHERE old_known_coin_id=coin_uuid;
spent_val = spent_val + tmp_val;
spent_frac = spent_frac + tmp_frac;
SELECT
SUM(amount_with_fee_val) -- overflow here is not plausible
,SUM(CAST(amount_with_fee_frac AS INT8)) -- compute using 64 bits
INTO
tmp_val
,tmp_frac
FROM refunds
WHERE known_coin_id=coin_uuid;
unspent_val = unspent_val + tmp_val;
unspent_frac = unspent_frac + tmp_frac;
SELECT
SUM(amount_val) -- overflow here is not plausible
,SUM(CAST(amount_frac AS INT8)) -- compute using 64 bits
INTO
tmp_val
,tmp_frac
FROM recoup_refresh
WHERE known_coin_id=coin_uuid;
unspent_val = unspent_val + tmp_val;
unspent_frac = unspent_frac + tmp_frac;
SELECT
SUM(amount_val) -- overflow here is not plausible
,SUM(CAST(amount_frac AS INT8)) -- compute using 64 bits
INTO
tmp_val
,tmp_frac
FROM recoup
WHERE known_coin_id=coin_uuid;
spent_val = spent_val + tmp_val;
spent_frac = spent_frac + tmp_frac;
SELECT
SUM(amount_val) -- overflow here is not plausible
,SUM(CAST(amount_frac AS INT8)) -- compute using 64 bits
INTO
tmp_val
,tmp_frac
FROM recoup_refresh
JOIN refresh_revealed_coins rrc
USING (rrc_serial)
JOIN refresh_commitments rfc
ON (rrc.melt_serial_id = rfc.melt_serial_id)
WHERE rfc.old_known_coin_id=coin_uuid;
spent_val = spent_val + tmp_val;
spent_frac = spent_frac + tmp_frac;
------------------- TBD from here
SELECT
reserve_uuid
,current_balance_val
,current_balance_frac_uuid
,expiration_date
,gc_date
INTO
reserve_uuid
,reserve_val
,reserve_frac
,reserve_gc
FROM reserves
WHERE reserve_pub=reserve_pub;
IF NOT FOUND
THEN
-- reserve unknown
reserve_found=FALSE;
balance_ok=FALSE;
kyc_ok=FALSE;
RETURN;
END IF;
-- We optimistically insert, and then on conflict declare
-- the query successful due to idempotency.
INSERT INTO reserves_out
(h_blind_ev
,denom_serial
,denom_sig
,reserve_uuid
,reserve_sig
,execution_date
,amount_with_fee_val
,amount_with_fee_frac)
VALUES
(h_coin_envelope
,denom_serial
,denom_sig
,reserve_uuid
,reserve_sig
,now
,amount_val
,amount_frac)
ON CONFLICT DO NOTHING;
IF NOT FOUND
THEN
-- idempotent query, all constraints must be satisfied
reserve_found=TRUE;
balance_ok=TRUE;
kyc_ok=TRUE;
RETURN;
END IF;
-- Check reserve balance is sufficient.
IF (reserve_val > amount_val)
THEN
IF (reserve_frac > amount_frac)
THEN
reserve_val=reserve_val - amount_val;
reserve_frac=reserve_frac - amount_frac;
ELSE
reserve_val=reserve_val - amount_val - 1;
reserve_frac=reserve_frac + 100000000 - amount_frac;
END IF;
ELSE
IF (reserve_val == amount_val) AND (reserve_frac >= amount_frac)
THEN
reserve_val=0;
reserve_frac=reserve_frac - amount_frac;
ELSE
reserve_found=TRUE;
balance_ok=FALSE;
kyc_ok=FALSE; -- we do not really know or care
RETURN;
END IF;
END IF;
-- Calculate new expiration dates.
min_reserve_gc=MAX(min_reserve_gc,reserve_gc);
-- Update reserve balance.
UPDATE reserves SET
gc_date=min_reserve_gc
,current_balance_val=reserve_val
,current_balance_frac=reserve_frac
WHERE
reserve_uuid=reserve_uuid;
reserve_found=TRUE;
balance_ok=TRUE;
-- Obtain KYC status based on the last wire transfer into
-- this reserve. FIXME: likely not adequate for reserves that got P2P transfers!
SELECT kyc_ok
INTO kyc_ok
FROM reserves_in
JOIN wire_targets USING (wire_target_serial_id)
WHERE reserve_uuid=reserve_uuid
LIMIT 1; -- limit 1 should not be required (without p2p transfers)
END $$;
COMMENT ON FUNCTION exchange_do_melt(INT8, INT4, BYTEA, BYTEA, BYTEA, BYTEA, BYTEA, INT8, INT8)
IS 'Checks whether the coin has sufficient balance for a melt operation (or the request is repeated and was previously approved) and if so updates the database with the result';
-- Complete transaction
-- COMMIT;
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