1 files changed, 85 insertions, 0 deletions
diff --git a/src/exchangedb/exchange_do_history_request.sql b/src/exchangedb/exchange_do_history_request.sql
new file mode 100644
index 000000000..2f6041741
--- /dev/null
+++ b/src/exchangedb/exchange_do_history_request.sql
@@ -0,0 +1,85 @@
+--
+-- 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_val INT8,
+  IN in_history_fee_frac INT4,
+  OUT out_balance_ok BOOLEAN,
+  OUT out_idempotent BOOLEAN)
+LANGUAGE plpgsql
+AS $$
+BEGIN
+
+  -- Insert and check for idempotency.
+  INSERT INTO exchange.history_requests
+  (reserve_pub
+  ,request_timestamp
+  ,reserve_sig
+  ,history_fee_val
+  ,history_fee_frac)
+  VALUES
+  (in_reserve_pub
+  ,in_request_timestamp
+  ,in_reserve_sig
+  ,in_history_fee_val
+  ,in_history_fee_frac)
+  ON CONFLICT DO NOTHING;
+
+  IF NOT FOUND
+  THEN
+    out_balance_ok=TRUE;
+    out_idempotent=TRUE;
+    RETURN;
+  END IF;
+
+  out_idempotent=FALSE;
+
+  -- Update reserve balance.
+  UPDATE exchange.reserves
+   SET
+    current_balance_frac=current_balance_frac-in_history_fee_frac
+       + CASE
+         WHEN current_balance_frac < in_history_fee_frac
+         THEN 100000000
+         ELSE 0
+         END,
+    current_balance_val=current_balance_val-in_history_fee_val
+       - CASE
+         WHEN current_balance_frac < in_history_fee_frac
+         THEN 1
+         ELSE 0
+         END
+  WHERE
+    reserve_pub=in_reserve_pub
+    AND ( (current_balance_val > in_history_fee_val) OR
+          ( (current_balance_frac >= in_history_fee_frac) AND
+            (current_balance_val >= in_history_fee_val) ) );
+
+  IF NOT FOUND
+  THEN
+    -- Either reserve does not exist, or balance insufficient.
+    -- Both we treat the same here as balance insufficient.
+    out_balance_ok=FALSE;
+    RETURN;
+  END IF;
+
+  out_balance_ok=TRUE;
+END $$;
+