-add DB logic for purse expiration

src/exchangedb/exchange-0001-part.sql

@@ -2505,7 +2505,8 @@ UPDATE known_coins
          THEN 1
          ELSE 0
          END
-  WHERE coin_pub=in_coin_pub;
+  WHERE coin_pub=in_coin_pub
+  LIMIT 1; -- just to be extra safe
 
 
 out_conflict=FALSE;
@@ -3360,6 +3361,70 @@ BEGIN
 END $$;
 
 
+
+CREATE OR REPLACE FUNCTION exchange_do_expire_purse(
+  IN in_partner_id INT8,
+  IN in_start_time INT8,
+  IN in_end_time INT8,
+  OUT out_found BOOLEAN)
+LANGUAGE plpgsql
+AS $$
+DECLARE
+  my_purse_pub BYTEA;
+DECLARE
+  my_deposit record;
+BEGIN
+
+UPDATE purse_requests
+ SET refunded=TRUE,
+     finished=TRUE
+ WHERE (purse_expiration >= in_start_time) AND
+       (purse_expiration < in_end_time) AND
+       (NOT finished) AND
+       (NOT refunded)
+ RETURNING purse_pub
+   ,in_reserve_quota
+   ,flags
+ INTO my_purse_pub
+   ,my_rq
+   ,my_flags;
+out_found = FOUND;
+IF NOT FOUND
+THEN
+  RETURN;
+END IF;
+
+-- restore balance to each coin deposited into the purse
+FOR my_deposit IN
+  SELECT coin_pub
+        ,amount_with_fee_val
+        ,amount_with_fee_frac
+    FROM purse_deposits
+  WHERE purse_pub = my_purse_pub
+LOOP
+  UPDATE
+    remaining_frac=remaining_frac+my_deposit.amount_with_fee_frac
+     - CASE
+       WHEN remaining_frac+my_deposit.amount_with_fee_frac >= 100000000
+       THEN 100000000
+       ELSE 0
+       END,
+    remaining_val=remaining_val+my_deposit.amount_with_fee_val
+     + CASE
+       WHEN remaining_frac+my_deposit.amount_with_fee_frac >= 100000000
+       THEN 1
+       ELSE 0
+       END
+    FROM known_coins
+    WHERE coin_pub = my_deposit.coin_pub
+    LIMIT 1; -- just to be extra safe
+  END LOOP;
+END $$;
+
+COMMENT ON FUNCTION exchange_do_expire_purse(INT8,INT8)
+  IS 'Finds an expired purse in the given time range and refunds the coins (if any).';
+
+
 CREATE OR REPLACE FUNCTION exchange_do_history_request(
   IN in_reserve_pub BYTEA,
   IN in_reserve_sig BYTEA,

src/exchangedb/plugin_exchangedb_postgres.c

@@ -904,6 +904,14 @@ prepare_statements (struct PostgresClosure *pg)
       " FROM exchange_do_purse_deposit"
       " ($1,$2,$3,$4,$5,$6,$7,$8);",
       8),
+    /* used in #postgres_expire_purse() */
+    GNUNET_PQ_make_prepare (
+      "call_expire_purse",
+      "SELECT "
+      " out_found AS found"
+      " FROM exchange_do_expire_purse"
+      " ($1,$2);",
+      2),
     /* Used in #postgres_do_melt() to melt a coin. */
     GNUNET_PQ_make_prepare (
       "call_melt",
@@ -13337,7 +13345,7 @@ postgres_select_contract_by_purse (void *cls,
  * @param[out] in_conflict set to true if @a econtract
  *             conflicts with an existing contract;
  *             in this case, the return value will be
- *             #GNUNET_DB_STATUS_SUCCESS_ONE despite the failure
+ *             #GNUNET_DB_STATUS_SUCCESS_ONE_RESULT despite the failure
  * @return transaction status code
  */
 static enum GNUNET_DB_QueryStatus
@@ -13568,8 +13576,30 @@ postgres_expire_purse (
   struct GNUNET_TIME_Absolute start_time,
   struct GNUNET_TIME_Absolute end_time)
 {
-  GNUNET_break (0);
-  return GNUNET_DB_STATUS_HARD_ERROR;
+  struct PostgresClosure *pg = cls;
+  struct GNUNET_PQ_QueryParam params[] = {
+    GNUNET_PQ_query_param_absolute_time (&start_time),
+    GNUNET_PQ_query_param_absolute_time (&end_time),
+    GNUNET_PQ_query_param_end
+  };
+  bool found = false;
+  struct GNUNET_PQ_ResultSpec rs[] = {
+    GNUNET_PQ_result_spec_bool ("found",
+                                &found),
+    GNUNET_PQ_result_spec_end
+  };
+  enum GNUNET_DB_QueryStatus qs;
+
+  qs = GNUNET_PQ_eval_prepared_singleton_select (pg->conn,
+                                                 "call_expire_purse",
+                                                 params,
+                                                 rs);
+  if (qs < 0)
+    return qs;
+  GNUNET_assert (GNUNET_DB_STATUS_SUCCESS_ONE_RESULT == qs);
+  return found
+    ? GNUNET_DB_STATUS_SUCCESS_ONE_RESULT
+    : GNUNET_DB_STATUS_SUCCESS_NO_RESULTS;
 }