cp sql/ from GNU Taler exchange

include/sql/exchange_do_melt.sql

@@ -0,0 +1,182 @@
+--
+-- 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_melt(
+  IN in_cs_rms BYTEA,
+  IN in_amount_with_fee taler_amount,
+  IN in_rc BYTEA,
+  IN in_old_coin_pub BYTEA,
+  IN in_old_coin_sig BYTEA,
+  IN in_known_coin_id INT8, -- not used, but that's OK
+  IN in_noreveal_index INT4,
+  IN in_zombie_required BOOLEAN,
+  OUT out_balance_ok BOOLEAN,
+  OUT out_zombie_bad BOOLEAN,
+  OUT out_noreveal_index INT4)
+LANGUAGE plpgsql
+AS $$
+DECLARE
+  denom_max INT8;
+BEGIN
+-- Shards: INSERT refresh_commitments (by rc)
+-- (rare:) SELECT refresh_commitments (by old_coin_pub) -- crosses shards!
+-- (rare:) SEELCT refresh_revealed_coins (by melt_serial_id)
+-- (rare:) PERFORM recoup_refresh (by rrc_serial) -- crosses shards!
+--         UPDATE known_coins (by coin_pub)
+
+INSERT INTO exchange.refresh_commitments
+  (rc
+  ,old_coin_pub
+  ,old_coin_sig
+  ,amount_with_fee
+  ,noreveal_index
+  )
+  VALUES
+  (in_rc
+  ,in_old_coin_pub
+  ,in_old_coin_sig
+  ,in_amount_with_fee
+  ,in_noreveal_index)
+  ON CONFLICT DO NOTHING;
+
+IF NOT FOUND
+THEN
+  -- Idempotency check: see if an identical record exists.
+  out_noreveal_index=-1;
+  SELECT
+     noreveal_index
+    INTO
+     out_noreveal_index
+    FROM exchange.refresh_commitments
+   WHERE rc=in_rc;
+  out_balance_ok=FOUND;
+  out_zombie_bad=FALSE; -- zombie is OK
+  RETURN;
+END IF;
+
+
+IF in_zombie_required
+THEN
+  -- Check if this coin was part of a refresh
+  -- operation that was subsequently involved
+  -- in a recoup operation.  We begin by all
+  -- refresh operations our coin was involved
+  -- with, then find all associated reveal
+  -- operations, and then see if any of these
+  -- reveal operations was involved in a recoup.
+  PERFORM
+    FROM recoup_refresh
+   WHERE rrc_serial IN
+    (SELECT rrc_serial
+       FROM refresh_revealed_coins
+      WHERE melt_serial_id IN
+      (SELECT melt_serial_id
+         FROM refresh_commitments
+        WHERE old_coin_pub=in_old_coin_pub));
+  IF NOT FOUND
+  THEN
+    out_zombie_bad=TRUE;
+    out_balance_ok=FALSE;
+    RETURN;
+  END IF;
+END IF;
+
+out_zombie_bad=FALSE; -- zombie is OK
+
+
+-- Check and update balance of the coin.
+UPDATE known_coins kc
+  SET
+    remaining.frac=(kc.remaining).frac-in_amount_with_fee.frac
+       + CASE
+         WHEN (kc.remaining).frac < in_amount_with_fee.frac
+         THEN 100000000
+         ELSE 0
+         END,
+    remaining.val=(kc.remaining).val-in_amount_with_fee.val
+       - CASE
+         WHEN (kc.remaining).frac < in_amount_with_fee.frac
+         THEN 1
+         ELSE 0
+         END
+  WHERE coin_pub=in_old_coin_pub
+    AND ( ((kc.remaining).val > in_amount_with_fee.val) OR
+          ( ((kc.remaining).frac >= in_amount_with_fee.frac) AND
+            ((kc.remaining).val >= in_amount_with_fee.val) ) );
+
+IF NOT FOUND
+THEN
+  -- Insufficient balance.
+  out_noreveal_index=-1;
+  out_balance_ok=FALSE;
+  RETURN;
+END IF;
+
+
+
+-- Special actions needed for a CS melt?
+IF in_cs_rms IS NOT NULL
+THEN
+  -- Get maximum denominations serial value in
+  -- existence, this will determine how long the
+  -- nonce will be locked.
+  SELECT
+      denominations_serial
+    INTO
+      denom_max
+    FROM exchange.denominations
+      ORDER BY denominations_serial DESC
+      LIMIT 1;
+
+  -- Cache CS signature to prevent replays in the future
+  -- (and check if cached signature exists at the same time).
+  INSERT INTO exchange.cs_nonce_locks
+    (nonce
+    ,max_denomination_serial
+    ,op_hash)
+  VALUES
+    (in_cs_rms
+    ,denom_max
+    ,in_rc)
+  ON CONFLICT DO NOTHING;
+
+  IF NOT FOUND
+  THEN
+    -- Record exists, make sure it is the same
+    SELECT 1
+      FROM exchange.cs_nonce_locks
+     WHERE nonce=in_cs_rms
+       AND op_hash=in_rc;
+
+    IF NOT FOUND
+    THEN
+       -- Nonce reuse detected
+       out_balance_ok=FALSE;
+       out_zombie_bad=FALSE;
+       out_noreveal_index=42; -- FIXME: return error message more nicely!
+       ASSERT false, 'nonce reuse attempted by client';
+    END IF;
+  END IF;
+END IF;
+
+-- Everything fine, return success!
+out_balance_ok=TRUE;
+out_noreveal_index=in_noreveal_index;
+
+END $$;