summaryrefslogtreecommitdiff
path: root/src/include/taler_exchangedb_plugin.h
blob: bb07d476d58e8221607ce0a64a7cc87c033f0eb4 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543
2544
2545
2546
2547
2548
2549
2550
2551
2552
2553
2554
2555
2556
2557
2558
2559
2560
2561
2562
2563
2564
2565
2566
2567
2568
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
2627
2628
2629
2630
2631
2632
2633
2634
2635
2636
2637
2638
2639
2640
2641
2642
2643
2644
2645
2646
2647
2648
2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661
2662
2663
2664
2665
2666
2667
2668
2669
2670
2671
2672
2673
2674
2675
2676
2677
2678
2679
2680
2681
2682
2683
2684
2685
2686
2687
2688
2689
2690
2691
2692
2693
2694
2695
2696
2697
2698
2699
2700
2701
2702
2703
2704
2705
2706
2707
2708
2709
2710
2711
2712
2713
2714
2715
2716
2717
2718
2719
2720
2721
2722
2723
2724
2725
2726
2727
2728
2729
2730
2731
2732
2733
2734
2735
2736
2737
2738
2739
2740
2741
2742
2743
2744
2745
2746
2747
2748
2749
2750
2751
2752
2753
2754
2755
2756
2757
2758
2759
2760
2761
2762
2763
2764
2765
2766
2767
2768
2769
2770
2771
2772
2773
2774
2775
2776
2777
2778
2779
2780
2781
2782
2783
2784
2785
2786
2787
2788
2789
2790
2791
2792
2793
2794
2795
2796
2797
2798
2799
2800
2801
2802
2803
2804
2805
2806
2807
2808
2809
2810
2811
2812
2813
2814
2815
2816
2817
2818
2819
2820
2821
2822
2823
2824
2825
2826
2827
2828
2829
2830
2831
2832
2833
2834
2835
2836
2837
2838
2839
2840
2841
2842
2843
2844
2845
2846
/*
  This file is part of TALER
  Copyright (C) 2014-2017 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/>
*/
/**
 * @file include/taler_exchangedb_plugin.h
 * @brief Low-level (statement-level) database access for the exchange
 * @author Florian Dold
 * @author Christian Grothoff
 */
#ifndef TALER_EXCHANGEDB_PLUGIN_H
#define TALER_EXCHANGEDB_PLUGIN_H
#include <jansson.h>
#include <gnunet/gnunet_util_lib.h>
#include <gnunet/gnunet_db_lib.h>
#include "taler_signatures.h"


GNUNET_NETWORK_STRUCT_BEGIN

/**
 * @brief On disk format used for a exchange signing key.  Signing keys are used
 * by the exchange to affirm its messages, but not to create coins.
 * Includes the private key followed by the public information about
 * the signing key.
 */
struct TALER_EXCHANGEDB_PrivateSigningKeyInformationP
{
  /**
   * Private key part of the exchange's signing key.
   */
  struct TALER_ExchangePrivateKeyP signkey_priv;

  /**
   * Signature over @e issue
   */
  struct TALER_MasterSignatureP master_sig;

  /**
   * Public information about a exchange signing key.
   */
  struct TALER_ExchangeSigningKeyValidityPS issue;

};


/**
 * Information about a denomination key.
 */
struct TALER_EXCHANGEDB_DenominationKeyInformationP
{

  /**
   * Signature over this struct to affirm the validity of the key.
   */
  struct TALER_MasterSignatureP signature;

  /**
   * Signed properties of the denomination key.
   */
  struct TALER_DenominationKeyValidityPS properties;
};


GNUNET_NETWORK_STRUCT_END


/**
 * @brief All information about a denomination key (which is used to
 * sign coins into existence).
 */
struct TALER_EXCHANGEDB_DenominationKey
{
  /**
   * The private key of the denomination.  Will be NULL if the private
   * key is not available (this is the case after the key has expired
   * for signing coins, but is still valid for depositing coins).
   */
  struct TALER_DenominationPrivateKey denom_priv;

  /**
   * Decoded denomination public key (the hash of it is in
   * @e issue, but we sometimes need the full public key as well).
   */
  struct TALER_DenominationPublicKey denom_pub;

  /**
   * Signed public information about a denomination key.
   */
  struct TALER_EXCHANGEDB_DenominationKeyInformationP issue;
};


/**
 * @brief Information we keep on bank transfer(s) that established a reserve.
 */
struct TALER_EXCHANGEDB_BankTransfer
{

  /**
   * Public key of the reserve that was filled.
   */
  struct TALER_ReservePublicKeyP reserve_pub;

  /**
   * Amount that was transferred to the exchange.
   */
  struct TALER_Amount amount;

  /**
   * When did the exchange receive the incoming transaction?
   * (This is the execution date of the exchange's database,
   * the execution date of the bank should be in @e wire).
   */
  struct GNUNET_TIME_Absolute execution_date;

  /**
   * Detailed wire information about the sending account
   * in "payto://" format.
   */
  char *sender_account_details;

  /**
   * Data uniquely identifying the wire transfer (wire transfer-type specific)
   */
  void *wire_reference;

  /**
   * Number of bytes in @e wire_reference.
   */
  size_t wire_reference_size;

};


/**
 * @brief Information we keep on bank transfer(s) that
 * closed a reserve.
 */
struct TALER_EXCHANGEDB_ClosingTransfer
{

  /**
   * Public key of the reserve that was depleted.
   */
  struct TALER_ReservePublicKeyP reserve_pub;

  /**
   * Amount that was transferred to the exchange.
   */
  struct TALER_Amount amount;

  /**
   * Amount that was charged by the exchange.
   */
  struct TALER_Amount closing_fee;

  /**
   * When did the exchange execute the transaction?
   */
  struct GNUNET_TIME_Absolute execution_date;

  /**
   * Detailed wire information about the receiving account
   * in payto://-format.
   */
  char *receiver_account_details;

  /**
   * Detailed wire transfer information that uniquely identifies the
   * wire transfer.
   */
  struct TALER_WireTransferIdentifierRawP wtid;

};


/**
 * @brief A summary of a Reserve
 */
struct TALER_EXCHANGEDB_Reserve
{
  /**
   * The reserve's public key.  This uniquely identifies the reserve
   */
  struct TALER_ReservePublicKeyP pub;

  /**
   * The balance amount existing in the reserve
   */
  struct TALER_Amount balance;

  /**
   * The expiration date of this reserve; funds will be wired back
   * at this time.
   */
  struct GNUNET_TIME_Absolute expiry;

  /**
   * The legal expiration date of this reserve; we will forget about
   * it at this time.
   */
  struct GNUNET_TIME_Absolute gc;
};


/**
 * @brief Information we keep for a withdrawn coin to reproduce
 * the /withdraw operation if needed, and to have proof
 * that a reserve was drained by this amount.
 */
struct TALER_EXCHANGEDB_CollectableBlindcoin
{

  /**
   * Our signature over the (blinded) coin.
   */
  struct TALER_DenominationSignature sig;

  /**
   * Hash of the denomination key (which coin was generated).
   */
  struct GNUNET_HashCode denom_pub_hash;

  /**
   * Value of the coin being exchangeed (matching the denomination key)
   * plus the transaction fee.  We include this in what is being
   * signed so that we can verify a reserve's remaining total balance
   * without needing to access the respective denomination key
   * information each time.
   */
  struct TALER_Amount amount_with_fee;

  /**
   * Withdrawl fee charged by the exchange.  This must match the Exchange's
   * denomination key's withdrawl fee.  If the client puts in an
   * invalid withdrawl fee (too high or too low) that does not match
   * the Exchange's denomination key, the withdraw operation is invalid
   * and will be rejected by the exchange.  The @e amount_with_fee minus
   * the @e withdraw_fee is must match the value of the generated
   * coin.  We include this in what is being signed so that we can
   * verify a exchange's accounting without needing to access the
   * respective denomination key information each time.
   */
  struct TALER_Amount withdraw_fee;

  /**
   * Public key of the reserve that was drained.
   */
  struct TALER_ReservePublicKeyP reserve_pub;

  /**
   * Hash over the blinded message, needed to verify
   * the @e reserve_sig.
   */
  struct GNUNET_HashCode h_coin_envelope;

  /**
   * Signature confirming the withdrawl, matching @e reserve_pub,
   * @e denom_pub and @e h_coin_envelope.
   */
  struct TALER_ReserveSignatureP reserve_sig;
};


/**
 * Information the exchange records about a recoup request
 * in a reserve history.
 */
struct TALER_EXCHANGEDB_Recoup
{

  /**
   * Information about the coin that was paid back.
   */
  struct TALER_CoinPublicInfo coin;

  /**
   * Blinding factor supplied to prove to the exchange that
   * the coin came from this reserve.
   */
  struct TALER_DenominationBlindingKeyP coin_blind;

  /**
   * Signature of the coin of type
   * #TALER_SIGNATURE_WALLET_COIN_RECOUP.
   */
  struct TALER_CoinSpendSignatureP coin_sig;

  /**
   * Public key of the reserve the coin was paid back into.
   */
  struct TALER_ReservePublicKeyP reserve_pub;

  /**
   * How much was the coin still worth at this time?
   */
  struct TALER_Amount value;

  /**
   * When did the recoup operation happen?
   */
  struct GNUNET_TIME_Absolute timestamp;

};


/**
 * Information the exchange records about a recoup request
 * in a coin history.
 */
struct TALER_EXCHANGEDB_RecoupListEntry
{

  /**
   * Blinding factor supplied to prove to the exchange that
   * the coin came from this reserve.
   */
  struct TALER_DenominationBlindingKeyP coin_blind;

  /**
   * Signature of the coin of type
   * #TALER_SIGNATURE_WALLET_COIN_RECOUP.
   */
  struct TALER_CoinSpendSignatureP coin_sig;

  /**
   * Public key of the reserve the coin was paid back into.
   */
  struct TALER_ReservePublicKeyP reserve_pub;

  /**
   * How much was the coin still worth at this time?
   */
  struct TALER_Amount value;

  /**
   * When did the /recoup operation happen?
   */
  struct GNUNET_TIME_Absolute timestamp;

};


/**
 * Information the exchange records about a recoup-refresh request in
 * a coin transaction history.
 */
struct TALER_EXCHANGEDB_RecoupRefreshListEntry
{

  /**
   * Information about the coin that was paid back
   * (NOT the coin we are considering the history of!)
   */
  struct TALER_CoinPublicInfo coin;

  /**
   * Blinding factor supplied to prove to the exchange that
   * the coin came from this reserve.
   */
  struct TALER_DenominationBlindingKeyP coin_blind;

  /**
   * Signature of the coin of type
   * #TALER_SIGNATURE_WALLET_COIN_RECOUP.
   */
  struct TALER_CoinSpendSignatureP coin_sig;

  /**
   * Public key of the old coin that the refreshed coin was paid back to.
   */
  struct TALER_CoinSpendPublicKeyP old_coin_pub;

  /**
   * How much was the coin still worth at this time?
   */
  struct TALER_Amount value;

  /**
   * When did the recoup operation happen?
   */
  struct GNUNET_TIME_Absolute timestamp;

};


/**
 * @brief Types of operations on a reserve.
 */
enum TALER_EXCHANGEDB_ReserveOperation
{
  /**
   * Money was deposited into the reserve via a bank transfer.
   * This is how customers establish a reserve at the exchange.
   */
  TALER_EXCHANGEDB_RO_BANK_TO_EXCHANGE = 0,

  /**
   * A Coin was withdrawn from the reserve using /withdraw.
   */
  TALER_EXCHANGEDB_RO_WITHDRAW_COIN = 1,

  /**
   * A coin was returned to the reserve using /recoup.
   */
  TALER_EXCHANGEDB_RO_RECOUP_COIN = 2,

  /**
   * The exchange send inactive funds back from the reserve to the
   * customer's bank account.  This happens when the exchange
   * closes a reserve with a non-zero amount left in it.
   */
  TALER_EXCHANGEDB_RO_EXCHANGE_TO_BANK = 3
};


/**
 * @brief Reserve history as a linked list.  Lists all of the transactions
 * associated with this reserve (such as the bank transfers that
 * established the reserve and all /withdraw operations we have done
 * since).
 */
struct TALER_EXCHANGEDB_ReserveHistory
{

  /**
   * Next entry in the reserve history.
   */
  struct TALER_EXCHANGEDB_ReserveHistory *next;

  /**
   * Type of the event, determins @e details.
   */
  enum TALER_EXCHANGEDB_ReserveOperation type;

  /**
   * Details of the operation, depending on @e type.
   */
  union
  {

    /**
     * Details about a bank transfer to the exchange (reserve
     * was established).
     */
    struct TALER_EXCHANGEDB_BankTransfer *bank;

    /**
     * Details about a /withdraw operation.
     */
    struct TALER_EXCHANGEDB_CollectableBlindcoin *withdraw;

    /**
     * Details about a /recoup operation.
     */
    struct TALER_EXCHANGEDB_Recoup *recoup;

    /**
     * Details about a bank transfer from the exchange (reserve
     * was closed).
     */
    struct TALER_EXCHANGEDB_ClosingTransfer *closing;

  } details;

};


/**
 * @brief Data from a deposit operation.  The combination of
 * the coin's public key, the merchant's public key and the
 * transaction ID must be unique.  While a coin can (theoretically) be
 * deposited at the same merchant twice (with partial spending), the
 * merchant must either use a different public key or a different
 * transaction ID for the two transactions.  The same coin must not
 * be used twice at the same merchant for the same transaction
 * (as determined by transaction ID).
 */
struct TALER_EXCHANGEDB_Deposit
{
  /**
   * Information about the coin that is being deposited.
   */
  struct TALER_CoinPublicInfo coin;

  /**
   * ECDSA signature affirming that the customer intends
   * this coin to be deposited at the merchant identified
   * by @e h_wire in relation to the proposal data identified
   * by @e h_contract_terms.
   */
  struct TALER_CoinSpendSignatureP csig;

  /**
   * Public key of the merchant.  Enables later identification
   * of the merchant in case of a need to rollback transactions.
   */
  struct TALER_MerchantPublicKeyP merchant_pub;

  /**
   * Hash over the proposa data between merchant and customer
   * (remains unknown to the Exchange).
   */
  struct GNUNET_HashCode h_contract_terms;

  /**
   * Hash of the (canonical) representation of @e wire, used
   * to check the signature on the request.  Generated by
   * the exchange from the detailed wire data provided by the
   * merchant.
   */
  struct GNUNET_HashCode h_wire;

  /**
   * Detailed information about the receiver for executing the transaction.
   * Includes URL in payto://-format and salt.
   */
  json_t *receiver_wire_account;

  /**
   * Time when this request was generated.  Used, for example, to
   * assess when (roughly) the income was achieved for tax purposes.
   * Note that the Exchange will only check that the timestamp is not "too
   * far" into the future (i.e. several days).  The fact that the
   * timestamp falls within the validity period of the coin's
   * denomination key is irrelevant for the validity of the deposit
   * request, as obviously the customer and merchant could conspire to
   * set any timestamp.  Also, the Exchange must accept very old deposit
   * requests, as the merchant might have been unable to transmit the
   * deposit request in a timely fashion (so back-dating is not
   * prevented).
   */
  struct GNUNET_TIME_Absolute timestamp;

  /**
   * How much time does the merchant have to issue a refund request?
   * Zero if refunds are not allowed.  After this time, the coin
   * cannot be refunded.
   */
  struct GNUNET_TIME_Absolute refund_deadline;

  /**
   * How much time does the merchant have to execute the wire transfer?
   * This time is advisory for aggregating transactions, not a hard
   * constraint (as the merchant can theoretically pick any time,
   * including one in the past).
   */
  struct GNUNET_TIME_Absolute wire_deadline;

  /**
   * Fraction of the coin's remaining value to be deposited, including
   * depositing fee (if any).  The coin is identified by @e coin_pub.
   */
  struct TALER_Amount amount_with_fee;

  /**
   * Depositing fee.
   */
  struct TALER_Amount deposit_fee;

};


/**
 * @brief Specification for a deposit operation in the
 * `struct TALER_EXCHANGEDB_TransactionList`.
 */
struct TALER_EXCHANGEDB_DepositListEntry
{

  /**
   * ECDSA signature affirming that the customer intends
   * this coin to be deposited at the merchant identified
   * by @e h_wire in relation to the proposal data identified
   * by @e h_contract_terms.
   */
  struct TALER_CoinSpendSignatureP csig;

  /**
   * Public key of the merchant.  Enables later identification
   * of the merchant in case of a need to rollback transactions.
   */
  struct TALER_MerchantPublicKeyP merchant_pub;

  /**
   * Hash over the proposa data between merchant and customer
   * (remains unknown to the Exchange).
   */
  struct GNUNET_HashCode h_contract_terms;

  /**
   * Hash of the (canonical) representation of @e wire, used
   * to check the signature on the request.  Generated by
   * the exchange from the detailed wire data provided by the
   * merchant.
   */
  struct GNUNET_HashCode h_wire;

  /**
   * Detailed information about the receiver for executing the transaction.
   * Includes URL in payto://-format and salt.
   */
  json_t *receiver_wire_account;

  /**
   * Time when this request was generated.  Used, for example, to
   * assess when (roughly) the income was achieved for tax purposes.
   * Note that the Exchange will only check that the timestamp is not "too
   * far" into the future (i.e. several days).  The fact that the
   * timestamp falls within the validity period of the coin's
   * denomination key is irrelevant for the validity of the deposit
   * request, as obviously the customer and merchant could conspire to
   * set any timestamp.  Also, the Exchange must accept very old deposit
   * requests, as the merchant might have been unable to transmit the
   * deposit request in a timely fashion (so back-dating is not
   * prevented).
   */
  struct GNUNET_TIME_Absolute timestamp;

  /**
   * How much time does the merchant have to issue a refund request?
   * Zero if refunds are not allowed.  After this time, the coin
   * cannot be refunded.
   */
  struct GNUNET_TIME_Absolute refund_deadline;

  /**
   * How much time does the merchant have to execute the wire transfer?
   * This time is advisory for aggregating transactions, not a hard
   * constraint (as the merchant can theoretically pick any time,
   * including one in the past).
   */
  struct GNUNET_TIME_Absolute wire_deadline;

  /**
   * Fraction of the coin's remaining value to be deposited, including
   * depositing fee (if any).  The coin is identified by @e coin_pub.
   */
  struct TALER_Amount amount_with_fee;

  /**
   * Depositing fee.
   */
  struct TALER_Amount deposit_fee;

};


/**
 * @brief Specification for a refund operation in a coin's transaction list.
 */
struct TALER_EXCHANGEDB_RefundListEntry
{

  /**
   * Public key of the merchant.
   */
  struct TALER_MerchantPublicKeyP merchant_pub;

  /**
   * Signature from the merchant affirming the refund.
   */
  struct TALER_MerchantSignatureP merchant_sig;

  /**
   * Hash over the proposal data between merchant and customer
   * (remains unknown to the Exchange).
   */
  struct GNUNET_HashCode h_contract_terms;

  /**
   * Merchant-generated REFUND transaction ID to detect duplicate
   * refunds.
   */
  uint64_t rtransaction_id;

  /**
   * Fraction of the original deposit's value to be refunded, including
   * refund fee (if any).  The coin is identified by @e coin_pub.
   */
  struct TALER_Amount refund_amount;

  /**
   * Refund fee to be covered by the customer.
   */
  struct TALER_Amount refund_fee;

};


/**
 * @brief Specification for a refund operation.  The combination of
 * the coin's public key, the merchant's public key and the
 * transaction ID must be unique.  While a coin can (theoretically) be
 * deposited at the same merchant twice (with partial spending), the
 * merchant must either use a different public key or a different
 * transaction ID for the two transactions.  The same goes for
 * refunds, hence we also have a "rtransaction" ID which is disjoint
 * from the transaction ID.  The same coin must not be used twice at
 * the same merchant for the same transaction or rtransaction ID.
 */
struct TALER_EXCHANGEDB_Refund
{
  /**
   * Information about the coin that is being refunded.
   */
  struct TALER_CoinPublicInfo coin;

  /**
   * Details about the refund.
   */
  struct TALER_EXCHANGEDB_RefundListEntry details;

};


/**
 * @brief Specification for coin in a melt operation.
 */
struct TALER_EXCHANGEDB_Refresh
{
  /**
   * Information about the coin that is being melted.
   */
  struct TALER_CoinPublicInfo coin;

  /**
   * Signature over the melting operation.
   */
  struct TALER_CoinSpendSignatureP coin_sig;

  /**
   * Refresh commitment this coin is melted into.
   */
  struct TALER_RefreshCommitmentP rc;

  /**
   * How much value is being melted?  This amount includes the fees,
   * so the final amount contributed to the melt is this value minus
   * the fee for melting the coin.  We include the fee in what is
   * being signed so that we can verify a reserve's remaining total
   * balance without needing to access the respective denomination key
   * information each time.
   */
  struct TALER_Amount amount_with_fee;

  /**
   * Index (smaller #TALER_CNC_KAPPA) which the exchange has chosen to not
   * have revealed during cut and choose.
   */
  uint32_t noreveal_index;

};


/**
 * Information about a /coins/$COIN_PUB/melt operation in a coin transaction history.
 */
struct TALER_EXCHANGEDB_MeltListEntry
{

  /**
   * Signature over the melting operation.
   */
  struct TALER_CoinSpendSignatureP coin_sig;

  /**
   * Refresh commitment this coin is melted into.
   */
  struct TALER_RefreshCommitmentP rc;

  /**
   * How much value is being melted?  This amount includes the fees,
   * so the final amount contributed to the melt is this value minus
   * the fee for melting the coin.  We include the fee in what is
   * being signed so that we can verify a reserve's remaining total
   * balance without needing to access the respective denomination key
   * information each time.
   */
  struct TALER_Amount amount_with_fee;

  /**
   * Melt fee the exchange charged.
   */
  struct TALER_Amount melt_fee;

  /**
   * Index (smaller #TALER_CNC_KAPPA) which the exchange has chosen to not
   * have revealed during cut and choose.
   */
  uint32_t noreveal_index;

};


/**
 * Information about a melt operation.
 */
struct TALER_EXCHANGEDB_Melt
{

  /**
   * Overall session data.
   */
  struct TALER_EXCHANGEDB_Refresh session;

  /**
   * Melt fee the exchange charged.
   */
  struct TALER_Amount melt_fee;

};


/**
 * @brief Linked list of refresh information linked to a coin.
 */
struct TALER_EXCHANGEDB_LinkList
{
  /**
   * Information is stored in a NULL-terminated linked list.
   */
  struct TALER_EXCHANGEDB_LinkList *next;

  /**
   * Denomination public key, determines the value of the coin.
   */
  struct TALER_DenominationPublicKey denom_pub;

  /**
   * Signature over the blinded envelope.
   */
  struct TALER_DenominationSignature ev_sig;

  /**
   * Signature of the original coin being refreshed over the
   * link data, of type #TALER_SIGNATURE_WALLET_COIN_LINK
   */
  struct TALER_CoinSpendSignatureP orig_coin_link_sig;
};


/**
 * @brief Enumeration to classify the different types of transactions
 * that can be done with a coin.
 */
enum TALER_EXCHANGEDB_TransactionType
{

  /**
   * Deposit operation.
   */
  TALER_EXCHANGEDB_TT_DEPOSIT = 0,

  /**
   * Melt operation.
   */
  TALER_EXCHANGEDB_TT_MELT = 1,

  /**
   * Refund operation.
   */
  TALER_EXCHANGEDB_TT_REFUND = 2,

  /**
   * Recoup-refresh operation (on the old coin, adding to the old coin's value)
   */
  TALER_EXCHANGEDB_TT_OLD_COIN_RECOUP = 3,

  /**
   * Recoup operation.
   */
  TALER_EXCHANGEDB_TT_RECOUP = 4,

  /**
   * Recoup-refresh operation (on the new coin, eliminating its value)
   */
  TALER_EXCHANGEDB_TT_RECOUP_REFRESH = 5

};


/**
 * @brief List of transactions we performed for a particular coin.
 */
struct TALER_EXCHANGEDB_TransactionList
{

  /**
   * Next pointer in the NULL-terminated linked list.
   */
  struct TALER_EXCHANGEDB_TransactionList *next;

  /**
   * Type of the transaction, determines what is stored in @e details.
   */
  enum TALER_EXCHANGEDB_TransactionType type;

  /**
   * Serial ID of this entry in the database.
   */
  uint64_t serial_id;

  /**
   * Details about the transaction, depending on @e type.
   */
  union
  {

    /**
     * Details if transaction was a deposit operation.
     * (#TALER_EXCHANGEDB_TT_DEPOSIT)
     */
    struct TALER_EXCHANGEDB_DepositListEntry *deposit;

    /**
     * Details if transaction was a melt operation.
     * (#TALER_EXCHANGEDB_TT_MELT)
     */
    struct TALER_EXCHANGEDB_MeltListEntry *melt;

    /**
     * Details if transaction was a refund operation.
     * (#TALER_EXCHANGEDB_TT_REFUND)
     */
    struct TALER_EXCHANGEDB_RefundListEntry *refund;

    /**
     * Details if transaction was a recoup-refund operation where
     * this coin was the OLD coin.
     * (#TALER_EXCHANGEDB_TT_OLD_COIN_RECOUP).
     */
    struct TALER_EXCHANGEDB_RecoupRefreshListEntry *old_coin_recoup;

    /**
     * Details if transaction was a recoup operation.
     * (#TALER_EXCHANGEDB_TT_RECOUP)
     */
    struct TALER_EXCHANGEDB_RecoupListEntry *recoup;

    /**
     * Details if transaction was a recoup-refund operation where
     * this coin was the REFRESHED coin.
     * (#TALER_EXCHANGEDB_TT_RECOUP_REFRESH)
     */
    struct TALER_EXCHANGEDB_RecoupRefreshListEntry *recoup_refresh;

  } details;

};


/**
 * @brief Handle for a database session (per-thread, for transactions).
 */
struct TALER_EXCHANGEDB_Session;


/**
 * Function called with details about deposits that have been made,
 * with the goal of executing the corresponding wire transaction.
 *
 * @param cls closure
 * @param rowid unique ID for the deposit in our DB, used for marking
 *              it as 'tiny' or 'done'
 * @param merchant_pub public key of the merchant
 * @param coin_pub public key of the coin
 * @param amount_with_fee amount that was deposited including fee
 * @param deposit_fee amount the exchange gets to keep as transaction fees
 * @param h_contract_terms hash of the proposal data known to merchant and customer
 * @param wire_deadline by which the merchant adviced that he would like the
 *        wire transfer to be executed
 * @param receiver_wire_account wire details for the merchant, includes
 *        'url' in payto://-format; NULL from iterate_matching_deposits()
 * @return transaction status code, #GNUNET_DB_STATUS_SUCCESS_ONE_RESULT to continue to iterate
 */
typedef enum GNUNET_DB_QueryStatus
(*TALER_EXCHANGEDB_DepositIterator)(void *cls,
                                    uint64_t rowid,
                                    const struct
                                    TALER_MerchantPublicKeyP *merchant_pub,
                                    const struct
                                    TALER_CoinSpendPublicKeyP *coin_pub,
                                    const struct TALER_Amount *amount_with_fee,
                                    const struct TALER_Amount *deposit_fee,
                                    const struct
                                    GNUNET_HashCode *h_contract_terms,
                                    struct GNUNET_TIME_Absolute wire_deadline,
                                    const json_t *receiver_wire_account);


/**
 * Callback with data about a prepared wire transfer.
 *
 * @param cls closure
 * @param rowid row identifier used to mark prepared transaction as done
 * @param wire_method which wire method is this preparation data for
 * @param buf transaction data that was persisted, NULL on error
 * @param buf_size number of bytes in @a buf, 0 on error
 */
typedef void
(*TALER_EXCHANGEDB_WirePreparationIterator) (void *cls,
                                             uint64_t rowid,
                                             const char *wire_method,
                                             const char *buf,
                                             size_t buf_size);


/**
 * Function called with details about deposits that have been made,
 * with the goal of auditing the deposit's execution.
 *
 * @param cls closure
 * @param rowid unique serial ID for the deposit in our DB
 * @param timestamp when did the deposit happen
 * @param merchant_pub public key of the merchant
 * @param denom_pub denomination public key of @a coin_pub
 * @param coin_pub public key of the coin
 * @param coin_sig signature from the coin
 * @param amount_with_fee amount that was deposited including fee
 * @param h_contract_terms hash of the proposal data known to merchant and customer
 * @param refund_deadline by which the merchant adviced that he might want
 *        to get a refund
 * @param wire_deadline by which the merchant adviced that he would like the
 *        wire transfer to be executed
 * @param receiver_wire_account wire details for the merchant including 'url' in payto://-format;
 *        NULL from iterate_matching_deposits()
 * @param done flag set if the deposit was already executed (or not)
 * @return #GNUNET_OK to continue to iterate, #GNUNET_SYSERR to stop
 */
typedef int
(*TALER_EXCHANGEDB_DepositCallback)(void *cls,
                                    uint64_t rowid,
                                    struct GNUNET_TIME_Absolute timestamp,
                                    const struct
                                    TALER_MerchantPublicKeyP *merchant_pub,
                                    const struct
                                    TALER_DenominationPublicKey *denom_pub,
                                    const struct
                                    TALER_CoinSpendPublicKeyP *coin_pub,
                                    const struct
                                    TALER_CoinSpendSignatureP *coin_sig,
                                    const struct TALER_Amount *amount_with_fee,
                                    const struct
                                    GNUNET_HashCode *h_contract_terms,
                                    struct GNUNET_TIME_Absolute refund_deadline,
                                    struct GNUNET_TIME_Absolute wire_deadline,
                                    const json_t *receiver_wire_account,
                                    int done);


/**
 * Function called with details about coins that were melted,
 * with the goal of auditing the refresh's execution.
 *
 * @param cls closure
 * @param rowid unique serial ID for the refresh session in our DB
 * @param denom_pub denomination public key of @a coin_pub
 * @param coin_pub public key of the coin
 * @param coin_sig signature from the coin
 * @param amount_with_fee amount that was deposited including fee
 * @param noreveal_index which index was picked by the exchange in cut-and-choose
 * @param rc what is the commitment
 * @return #GNUNET_OK to continue to iterate, #GNUNET_SYSERR to stop
 */
typedef int
(*TALER_EXCHANGEDB_RefreshesCallback)(void *cls,
                                      uint64_t rowid,
                                      const struct
                                      TALER_DenominationPublicKey *
                                      denom_pub,
                                      const struct
                                      TALER_CoinSpendPublicKeyP *coin_pub,
                                      const struct
                                      TALER_CoinSpendSignatureP *coin_sig,
                                      const struct
                                      TALER_Amount *amount_with_fee,
                                      uint32_t noreveal_index,
                                      const struct
                                      TALER_RefreshCommitmentP *rc);


/**
 * Callback invoked with information about refunds applicable
 * to a particular coin and contract.
 *
 * @param cls closure
 * @param amount_with_fee amount being refunded
 * @return #GNUNET_OK to continue to iterate, #GNUNET_SYSERR to stop
 */
typedef int
(*TALER_EXCHANGEDB_RefundCoinCallback)(void *cls,
                                       const struct
                                       TALER_Amount *amount_with_fee);


/**
 * Information about a coin that was revealed to the exchange
 * during reveal.
 */
struct TALER_EXCHANGEDB_RefreshRevealedCoin
{
  /**
   * Public denomination key of the coin.
   */
  struct TALER_DenominationPublicKey denom_pub;

  /**
   * Signature of the original coin being refreshed over the
   * link data, of type #TALER_SIGNATURE_WALLET_COIN_LINK
   */
  struct TALER_CoinSpendSignatureP orig_coin_link_sig;

  /**
   * Blinded message to be signed (in envelope), with @e coin_env_size bytes.
   */
  char *coin_ev;

  /**
   * Number of bytes in @e coin_ev.
   */
  size_t coin_ev_size;

  /**
   * Signature generated by the exchange over the coin (in blinded format).
   */
  struct TALER_DenominationSignature coin_sig;
};


/**
 * Function called with information about a refresh order.
 *
 * @param cls closure
 * @param rowid unique serial ID for the row in our database
 * @param num_newcoins size of the @a rrcs array
 * @param rrcs array of @a num_newcoins information about coins to be created
 * @param num_tprivs number of entries in @a tprivs, should be #TALER_CNC_KAPPA - 1
 * @param tprivs array of @e num_tprivs transfer private keys
 * @param tp transfer public key information
 */
typedef void
(*TALER_EXCHANGEDB_RefreshCallback)(void *cls,
                                    uint32_t num_newcoins,
                                    const struct
                                    TALER_EXCHANGEDB_RefreshRevealedCoin *rrcs,
                                    unsigned int num_tprivs,
                                    const struct
                                    TALER_TransferPrivateKeyP *tprivs,
                                    const struct TALER_TransferPublicKeyP *tp);


/**
 * Function called with details about coins that were refunding,
 * with the goal of auditing the refund's execution.
 *
 * @param cls closure
 * @param rowid unique serial ID for the refund in our DB
 * @param denom_pub denomination public key of @a coin_pub
 * @param coin_pub public key of the coin
 * @param merchant_pub public key of the merchant
 * @param merchant_sig signature of the merchant
 * @param h_contract_terms hash of the proposal data known to merchant and customer
 * @param rtransaction_id refund transaction ID chosen by the merchant
 * @param amount_with_fee amount that was deposited including fee
 * @return #GNUNET_OK to continue to iterate, #GNUNET_SYSERR to stop
 */
typedef int
(*TALER_EXCHANGEDB_RefundCallback)(void *cls,
                                   uint64_t rowid,
                                   const struct
                                   TALER_DenominationPublicKey *denom_pub,
                                   const struct
                                   TALER_CoinSpendPublicKeyP *coin_pub,
                                   const struct
                                   TALER_MerchantPublicKeyP *merchant_pub,
                                   const struct
                                   TALER_MerchantSignatureP *merchant_sig,
                                   const struct
                                   GNUNET_HashCode *h_contract_terms,
                                   uint64_t rtransaction_id,
                                   const struct TALER_Amount *amount_with_fee);


/**
 * Function called with details about incoming wire transfers.
 *
 * @param cls closure
 * @param rowid unique serial ID for the refresh session in our DB
 * @param reserve_pub public key of the reserve (also the WTID)
 * @param credit amount that was received
 * @param sender_account_details information about the sender's bank account, in payto://-format
 * @param wire_reference unique identifier for the wire transfer
 * @param execution_date when did we receive the funds
 * @return #GNUNET_OK to continue to iterate, #GNUNET_SYSERR to stop
 */
typedef int
(*TALER_EXCHANGEDB_ReserveInCallback)(void *cls,
                                      uint64_t rowid,
                                      const struct
                                      TALER_ReservePublicKeyP *reserve_pub,
                                      const struct TALER_Amount *credit,
                                      const char *sender_account_details,
                                      uint64_t wire_reference,
                                      struct GNUNET_TIME_Absolute
                                      execution_date);


/**
 * Function called with details about withdraw operations.
 *
 * @param cls closure
 * @param rowid unique serial ID for the refresh session in our DB
 * @param h_blind_ev blinded hash of the coin's public key
 * @param denom_pub public denomination key of the deposited coin
 * @param reserve_pub public key of the reserve
 * @param reserve_sig signature over the withdraw operation
 * @param execution_date when did the wallet withdraw the coin
 * @param amount_with_fee amount that was withdrawn
 * @return #GNUNET_OK to continue to iterate, #GNUNET_SYSERR to stop
 */
typedef int
(*TALER_EXCHANGEDB_WithdrawCallback)(void *cls,
                                     uint64_t rowid,
                                     const struct GNUNET_HashCode *h_blind_ev,
                                     const struct
                                     TALER_DenominationPublicKey *denom_pub,
                                     const struct
                                     TALER_ReservePublicKeyP *reserve_pub,
                                     const struct
                                     TALER_ReserveSignatureP *reserve_sig,
                                     struct GNUNET_TIME_Absolute execution_date,
                                     const struct
                                     TALER_Amount *amount_with_fee);


/**
 * Function called with the session hashes and transfer secret
 * information for a given coin.
 *
 * @param cls closure
 * @param transfer_pub public transfer key for the session
 * @param ldl link data for @a transfer_pub
 */
typedef void
(*TALER_EXCHANGEDB_LinkCallback)(void *cls,
                                 const struct
                                 TALER_TransferPublicKeyP *transfer_pub,
                                 const struct TALER_EXCHANGEDB_LinkList *ldl);


/**
 * Function called with the results of the lookup of the wire transfer
 * identifier information.  Only called if we are at least aware of the
 * transaction existing.
 *
 * @param cls closure
 * @param wtid wire transfer identifier, NULL
 *         if the transaction was not yet done
 * @param coin_contribution how much did the coin we asked about
 *        contribute to the total transfer value? (deposit value including fee)
 * @param coin_fee how much did the exchange charge for the deposit fee
 * @param execution_time when was the transaction done, or
 *         when we expect it to be done (if @a wtid was NULL)
 */
typedef void
(*TALER_EXCHANGEDB_WireTransferByCoinCallback)(void *cls,
                                               const struct
                                               TALER_WireTransferIdentifierRawP
                                               *
                                               wtid,
                                               const struct
                                               TALER_Amount *coin_contribution,
                                               const struct
                                               TALER_Amount *coin_fee,
                                               struct GNUNET_TIME_Absolute
                                               execution_time);


/**
 * Function called with the results of the lookup of the
 * transaction data associated with a wire transfer identifier.
 *
 * @param cls closure
 * @param rowid which row in the table is the information from (for diagnostics)
 * @param merchant_pub public key of the merchant (should be same for all callbacks with the same @e cls)
 * @param h_wire hash of wire transfer details of the merchant (should be same for all callbacks with the same @e cls)
 * @param account_details which account did the transfer go to?
 * @param exec_time execution time of the wire transfer (should be same for all callbacks with the same @e cls)
 * @param h_contract_terms which proposal was this payment about
 * @param denom_pub denomination of @a coin_pub
 * @param coin_pub which public key was this payment about
 * @param coin_value amount contributed by this coin in total (with fee)
 * @param coin_fee applicable fee for this coin
 */
typedef void
(*TALER_EXCHANGEDB_AggregationDataCallback)(void *cls,
                                            uint64_t rowid,
                                            const struct
                                            TALER_MerchantPublicKeyP *
                                            merchant_pub,
                                            const struct
                                            GNUNET_HashCode *h_wire,
                                            const json_t *account_details,
                                            struct GNUNET_TIME_Absolute
                                            exec_time,
                                            const struct
                                            GNUNET_HashCode *h_contract_terms,
                                            const struct
                                            TALER_DenominationPublicKey *
                                            denom_pub,
                                            const struct
                                            TALER_CoinSpendPublicKeyP *coin_pub,
                                            const struct
                                            TALER_Amount *coin_value,
                                            const struct
                                            TALER_Amount *coin_fee);


/**
 * Function called with the results of the lookup of the
 * wire transfer data of the exchange.
 *
 * @param cls closure
 * @param rowid identifier of the respective row in the database
 * @param date timestamp of the wire transfer (roughly)
 * @param wtid wire transfer subject
 * @param wire wire transfer details of the receiver, including "url" in payto://-format
 * @param amount amount that was wired
 * @return #GNUNET_OK to continue, #GNUNET_SYSERR to stop iteration
 */
typedef int
(*TALER_EXCHANGEDB_WireTransferOutCallback)(void *cls,
                                            uint64_t rowid,
                                            struct GNUNET_TIME_Absolute date,
                                            const struct
                                            TALER_WireTransferIdentifierRawP *
                                            wtid,
                                            const json_t *wire,
                                            const struct TALER_Amount *amount);


/**
 * Callback with data about a prepared wire transfer.
 *
 * @param cls closure
 * @param rowid row identifier used to mark prepared transaction as done
 * @param wire_method which wire method is this preparation data for
 * @param buf transaction data that was persisted, NULL on error
 * @param buf_size number of bytes in @a buf, 0 on error
 * @param finished did we complete the transfer yet?
 * @return #GNUNET_OK to continue, #GNUNET_SYSERR to stop iteration
 */
typedef int
(*TALER_EXCHANGEDB_WirePreparationCallback)(void *cls,
                                            uint64_t rowid,
                                            const char *wire_method,
                                            const char *buf,
                                            size_t buf_size,
                                            int finished);


/**
 * Function called about recoups the exchange has to perform.
 *
 * @param cls closure
 * @param rowid row identifier used to uniquely identify the recoup operation
 * @param timestamp when did we receive the recoup request
 * @param amount how much should be added back to the reserve
 * @param reserve_pub public key of the reserve
 * @param coin public information about the coin
 * @param coin_sig signature with @e coin_pub of type #TALER_SIGNATURE_WALLET_COIN_RECOUP
 * @param coin_blind blinding factor used to blind the coin
 * @return #GNUNET_OK to continue to iterate, #GNUNET_SYSERR to stop
 */
typedef int
(*TALER_EXCHANGEDB_RecoupCallback)(void *cls,
                                   uint64_t rowid,
                                   struct GNUNET_TIME_Absolute timestamp,
                                   const struct TALER_Amount *amount,
                                   const struct
                                   TALER_ReservePublicKeyP *reserve_pub,
                                   const struct TALER_CoinPublicInfo *coin,
                                   const struct
                                   TALER_DenominationPublicKey *denom_pub,
                                   const struct
                                   TALER_CoinSpendSignatureP *coin_sig,
                                   const struct
                                   TALER_DenominationBlindingKeyP *coin_blind);


/**
 * Function called about recoups on refreshed coins the exchange has to
 * perform.
 *
 * @param cls closure
 * @param rowid row identifier used to uniquely identify the recoup operation
 * @param timestamp when did we receive the recoup request
 * @param amount how much should be added back to the reserve
 * @param old_coin_pub original coin that was refreshed to create @a coin
 * @param coin public information about the coin
 * @param coin_sig signature with @e coin_pub of type #TALER_SIGNATURE_WALLET_COIN_RECOUP
 * @param coin_blind blinding factor used to blind the coin
 * @return #GNUNET_OK to continue to iterate, #GNUNET_SYSERR to stop
 */
typedef int
(*TALER_EXCHANGEDB_RecoupRefreshCallback)(void *cls,
                                          uint64_t rowid,
                                          struct GNUNET_TIME_Absolute
                                          timestamp,
                                          const struct TALER_Amount *amount,
                                          const struct
                                          TALER_CoinSpendPublicKeyP *
                                          old_coin_pub,
                                          const struct
                                          TALER_CoinPublicInfo *coin,
                                          const struct
                                          TALER_DenominationPublicKey *
                                          denom_pub,
                                          const struct
                                          TALER_CoinSpendSignatureP *coin_sig,
                                          const struct
                                          TALER_DenominationBlindingKeyP *
                                          coin_blind);


/**
 * Function called about reserve closing operations
 * the aggregator triggered.
 *
 * @param cls closure
 * @param rowid row identifier used to uniquely identify the reserve closing operation
 * @param execution_date when did we execute the close operation
 * @param amount_with_fee how much did we debit the reserve
 * @param closing_fee how much did we charge for closing the reserve
 * @param reserve_pub public key of the reserve
 * @param receiver_account where did we send the funds, in payto://-format
 * @param wtid identifier used for the wire transfer
 * @return #GNUNET_OK to continue to iterate, #GNUNET_SYSERR to stop
 */
typedef int
(*TALER_EXCHANGEDB_ReserveClosedCallback)(void *cls,
                                          uint64_t rowid,
                                          struct GNUNET_TIME_Absolute
                                          execution_date,
                                          const struct
                                          TALER_Amount *amount_with_fee,
                                          const struct
                                          TALER_Amount *closing_fee,
                                          const struct
                                          TALER_ReservePublicKeyP *reserve_pub,
                                          const char *receiver_account,
                                          const struct
                                          TALER_WireTransferIdentifierRawP *wtid);


/**
 * Function called with details about expired reserves.
 *
 * @param cls closure
 * @param reserve_pub public key of the reserve
 * @param left amount left in the reserve
 * @param account_details information about the reserve's bank account, in payto://-format
 * @param expiration_date when did the reserve expire
 * @return transaction status code to pass on
 */
typedef enum GNUNET_DB_QueryStatus
(*TALER_EXCHANGEDB_ReserveExpiredCallback)(void *cls,
                                           const struct
                                           TALER_ReservePublicKeyP *reserve_pub,
                                           const struct TALER_Amount *left,
                                           const char *account_details,
                                           struct GNUNET_TIME_Absolute
                                           expiration_date);


/**
 * Function called with information justifying an aggregate recoup.
 * (usually implemented by the auditor when verifying losses from recoups).
 *
 * @param cls closure
 * @param rowid row identifier used to uniquely identify the recoup operation
 * @param coin information about the coin
 * @param coin_sig signature of the coin of type #TALER_SIGNATURE_WALLET_COIN_RECOUP
 * @param coin_blind blinding key of the coin
 * @param h_blind_ev blinded envelope, as calculated by the exchange
 * @param amount total amount to be paid back
 */
typedef void
(*TALER_EXCHANGEDB_RecoupJustificationCallback)(void *cls,
                                                uint64_t rowid,
                                                const struct
                                                TALER_CoinPublicInfo *coin,
                                                const struct
                                                TALER_CoinSpendSignatureP *
                                                coin_sig,
                                                const struct
                                                TALER_DenominationBlindingKeyP
                                                *coin_blind,
                                                const struct
                                                GNUNET_HashCode *h_blinded_ev,
                                                const struct
                                                TALER_Amount *amount);


/**
 * Function called on deposits that are past their due date
 * and have not yet seen a wire transfer.
 *
 * @param cls closure
 * @param rowid deposit table row of the coin's deposit
 * @param coin_pub public key of the coin
 * @param amount value of the deposit, including fee
 * @param wire where should the funds be wired, including 'url' in payto://-format
 * @param deadline what was the requested wire transfer deadline
 * @param tiny did the exchange defer this transfer because it is too small?
 * @param done did the exchange claim that it made a transfer?
 */
typedef void
(*TALER_EXCHANGEDB_WireMissingCallback)(void *cls,
                                        uint64_t rowid,
                                        const struct
                                        TALER_CoinSpendPublicKeyP *coin_pub,
                                        const struct TALER_Amount *amount,
                                        const json_t *wire,
                                        struct GNUNET_TIME_Absolute deadline,
                                        /* bool? */ int tiny,
                                        /* bool? */ int done);


/**
 * Function called with information about the exchange's denomination keys.
 *
 * @param cls closure
 * @param denom_pub public key of the denomination
 * @param issue detailed information about the denomination (value, expiration times, fees)
 */
typedef void
(*TALER_EXCHANGEDB_DenominationCallback)(void *cls,
                                         const struct
                                         TALER_DenominationPublicKey *denom_pub,
                                         const struct
                                         TALER_EXCHANGEDB_DenominationKeyInformationP
                                         *issue);


/**
 * @brief The plugin API, returned from the plugin's "init" function.
 * The argument given to "init" is simply a configuration handle.
 */
struct TALER_EXCHANGEDB_Plugin
{

  /**
   * Closure for all callbacks.
   */
  void *cls;

  /**
   * Name of the library which generated this plugin.  Set by the
   * plugin loader.
   */
  char *library_name;

  /**
   * Get the thread-local (!) database-handle.
   * Connect to the db if the connection does not exist yet.
   *
   * @param cls the @e cls of this struct with the plugin-specific state
   * @returns the database connection, or NULL on error
   */
  struct TALER_EXCHANGEDB_Session *
  (*get_session) (void *cls);


  /**
   * Drop the Taler tables.  This should only be used in testcases.
   *
   * @param cls the @e cls of this struct with the plugin-specific state
   * @return #GNUNET_OK upon success; #GNUNET_SYSERR upon failure
   */
  int
  (*drop_tables) (void *cls);


  /**
   * Create the necessary tables if they are not present
   *
   * @param cls the @e cls of this struct with the plugin-specific state
   * @return #GNUNET_OK upon success; #GNUNET_SYSERR upon failure
   */
  int
  (*create_tables) (void *cls);


  /**
   * Start a transaction.
   *
   * @param cls the @e cls of this struct with the plugin-specific state
   * @param session connection to use
   * @param name unique name identifying the transaction (for debugging),
   *             must point to a constant
   * @return #GNUNET_OK on success
   */
  int
  (*start) (void *cls,
            struct TALER_EXCHANGEDB_Session *session,
            const char *name);


  /**
   * Commit a transaction.
   *
   * @param cls the @e cls of this struct with the plugin-specific state
   * @param session connection to use
   * @return transaction status
   */
  enum GNUNET_DB_QueryStatus
  (*commit)(void *cls,
            struct TALER_EXCHANGEDB_Session *session);


  /**
   * Do a pre-flight check that we are not in an uncommitted transaction.
   * If we are, try to commit the previous transaction and output a warning.
   * Does not return anything, as we will continue regardless of the outcome.
   *
   * @param cls the `struct PostgresClosure` with the plugin-specific state
   * @param session the database connection
   */
  void
  (*preflight) (void *cls,
                struct TALER_EXCHANGEDB_Session *session);


  /**
   * Abort/rollback a transaction.
   *
   * @param cls the @e cls of this struct with the plugin-specific state
   * @param session connection to use
   */
  void
  (*rollback) (void *cls,
               struct TALER_EXCHANGEDB_Session *session);


  /**
   * Insert information about a denomination key and in particular
   * the properties (value, fees, expiration times) the coins signed
   * with this key have.
   *
   * @param cls the @e cls of this struct with the plugin-specific state
   * @param session connection to use
   * @param denom_pub the public key used for signing coins of this denomination
   * @param issue issuing information with value, fees and other info about the denomination
   * @return status of the query
   */
  enum GNUNET_DB_QueryStatus
  (*insert_denomination_info)(void *cls,
                              struct TALER_EXCHANGEDB_Session *session,
                              const struct
                              TALER_DenominationPublicKey *denom_pub,
                              const struct
                              TALER_EXCHANGEDB_DenominationKeyInformationP *
                              issue);


  /**
   * Fetch information about a denomination key.
   *
   * @param cls the @e cls of this struct with the plugin-specific state
   * @param session connection to use
   * @param denom_pub_hash hash of the public key used for signing coins of this denomination
   * @param[out] issue set to issue information with value, fees and other info about the coin
   * @return transaction status code
   */
  enum GNUNET_DB_QueryStatus
  (*get_denomination_info)(void *cls,
                           struct TALER_EXCHANGEDB_Session *session,
                           const struct GNUNET_HashCode *denom_pub_hash,
                           struct TALER_EXCHANGEDB_DenominationKeyInformationP *
                           issue);


  /**
   * Function called on every known denomination key.  Runs in its
   * own read-only transaction (hence no session provided).
   *
   * @param cls the @e cls of this struct with the plugin-specific state
   * @param cb function to call on each denomination key
   * @param cb_cls closure for @a cb
   * @return transaction status code
   */
  enum GNUNET_DB_QueryStatus
  (*iterate_denomination_info)(void *cls,
                               TALER_EXCHANGEDB_DenominationCallback cb,
                               void *cb_cls);

  /**
   * Get the summary of a reserve.
   *
   * @param cls the @e cls of this struct with the plugin-specific state
   * @param session the database connection handle
   * @param[in,out] reserve the reserve data.  The public key of the reserve should be set
   *          in this structure; it is used to query the database.  The balance
   *          and expiration are then filled accordingly.
   * @return transaction status
   */
  enum GNUNET_DB_QueryStatus
  (*reserves_get)(void *cls,
                  struct TALER_EXCHANGEDB_Session *session,
                  struct TALER_EXCHANGEDB_Reserve *reserve);


  /**
   * Insert a incoming transaction into reserves.  New reserves are
   * also created through this function.
   *
   * @param cls the @e cls of this struct with the plugin-specific state
   * @param session the database session handle
   * @param reserve_pub public key of the reserve
   * @param balance the amount that has to be added to the reserve
   * @param execution_time when was the amount added
   * @param sender_account_details information about the sender's bank account, in payto://-format
   * @param wire_reference unique reference identifying the wire transfer
   * @return transaction status code
   */
  enum GNUNET_DB_QueryStatus
  (*reserves_in_insert)(void *cls,
                        struct TALER_EXCHANGEDB_Session *session,
                        const struct TALER_ReservePublicKeyP *reserve_pub,
                        const struct TALER_Amount *balance,
                        struct GNUNET_TIME_Absolute execution_time,
                        const char *sender_account_details,
                        const char *exchange_account_name,
                        uint64_t wire_reference);


  /**
   * Obtain the most recent @a wire_reference that was inserted via @e reserves_in_insert.
   * Used by the wirewatch process when resuming.
   *
   * @param cls the @e cls of this struct with the plugin-specific state
   * @param session the database connection handle
   * @param exchange_account_name name of the section in the exchange's configuration
   *                       for the account that we are tracking here
   * @param[out] wire_reference set to unique reference identifying the wire transfer
   * @return transaction status code
   */
  enum GNUNET_DB_QueryStatus
  (*get_latest_reserve_in_reference)(void *cls,
                                     struct TALER_EXCHANGEDB_Session *session,
                                     const char *exchange_account_name,
                                     uint64_t *wire_reference);


  /**
   * Locate the response for a withdraw request under the
   * key of the hash of the blinded message.  Used to ensure
   * idempotency of the request.
   *
   * @param cls the @e cls of this struct with the plugin-specific state
   * @param session database connection to use
   * @param h_blind hash of the blinded coin to be signed (will match
   *                `h_coin_envelope` in the @a collectable to be returned)
   * @param collectable corresponding collectable coin (blind signature)
   *                    if a coin is found
   * @return statement execution status
   */
  enum GNUNET_DB_QueryStatus
  (*get_withdraw_info)(void *cls,
                       struct TALER_EXCHANGEDB_Session *session,
                       const struct GNUNET_HashCode *h_blind,
                       struct TALER_EXCHANGEDB_CollectableBlindcoin *collectable);


  /**
   * Store collectable coin under the corresponding hash of the blinded
   * message.
   *
   * @param cls the @e cls of this struct with the plugin-specific state
   * @param session database connection to use
   * @param collectable corresponding collectable coin (blind signature)
   *                    if a coin is found
   * @return statement execution status
   */
  enum GNUNET_DB_QueryStatus
  (*insert_withdraw_info)(void *cls,
                          struct TALER_EXCHANGEDB_Session *session,
                          const struct
                          TALER_EXCHANGEDB_CollectableBlindcoin *collectable);


  /**
   * Get all of the transaction history associated with the specified
   * reserve.
   *
   * @param cls the @e cls of this struct with the plugin-specific state
   * @param session connection to use
   * @param reserve_pub public key of the reserve
   * @param[out] rhp set to known transaction history (NULL if reserve is unknown)
   * @return transaction status
   */
  enum GNUNET_DB_QueryStatus
  (*get_reserve_history)(void *cls,
                         struct TALER_EXCHANGEDB_Session *session,
                         const struct TALER_ReservePublicKeyP *reserve_pub,
                         struct TALER_EXCHANGEDB_ReserveHistory **rhp);


  /**
   * Free memory associated with the given reserve history.
   *
   * @param cls the @e cls of this struct with the plugin-specific state
   * @param rh history to free.
   */
  void
  (*free_reserve_history) (void *cls,
                           struct TALER_EXCHANGEDB_ReserveHistory *rh);


  /**
   * Count the number of known coins by denomination.
   *
   * @param cls database connection plugin state
   * @param session database session
   * @param denom_pub_hash denomination to count by
   * @return number of coins if non-negative, otherwise an `enum GNUNET_DB_QueryStatus`
   */
  long long
  (*count_known_coins) (void *cls,
                        struct TALER_EXCHANGEDB_Session *session,
                        const struct GNUNET_HashCode *denom_pub_hash);


  /**
   * Make sure the given @a coin is known to the database.
   *
   * @param cls database connection plugin state
   * @param session database session
   * @param coin the coin that must be made known
   * @return database transaction status, non-negative on success
   */
  enum GNUNET_DB_QueryStatus
  (*ensure_coin_known)(void *cls,
                       struct TALER_EXCHANGEDB_Session *session,
                       const struct TALER_CoinPublicInfo *coin);


  /**
   * Retrieve information about the given @a coin from the database.
   *
   * @param cls database connection plugin state
   * @param session database session
   * @param coin the coin that must be made known
   * @return database transaction status, non-negative on success
   */
  enum GNUNET_DB_QueryStatus
  (*get_known_coin)(void *cls,
                    struct TALER_EXCHANGEDB_Session *session,
                    const struct TALER_CoinSpendPublicKeyP *coin_pub,
                    struct TALER_CoinPublicInfo *coin_info);


  /**
   * Retrieve the denomination of a known coin.
   *
   * @param cls the plugin closure
   * @param session the database session handle
   * @param coin_pub the public key of the coin to search for
   * @param[out] denom_hash where to store the hash of the coins denomination
   * @return transaction status code
   */
  enum GNUNET_DB_QueryStatus
  (*get_coin_denomination)(void *cls,
                           struct TALER_EXCHANGEDB_Session *session,
                           const struct TALER_CoinSpendPublicKeyP *coin_pub,
                           struct GNUNET_HashCode *denom_hash);


  /**
   * Check if we have the specified deposit already in the database.
   *
   * @param cls the @e cls of this struct with the plugin-specific state
   * @param session database connection
   * @param deposit deposit to search for
   * @param check_extras wether to check extra fields or not
   * @return 1 if we know this operation,
   *         0 if this exact deposit is unknown to us,
   *         otherwise transaction error status
   */
  enum GNUNET_DB_QueryStatus
  (*have_deposit)(void *cls,
                  struct TALER_EXCHANGEDB_Session *session,
                  const struct TALER_EXCHANGEDB_Deposit *deposit,
                  int check_extras);


  /**
   * Insert information about deposited coin into the database.
   *
   * @param cls the @e cls of this struct with the plugin-specific state
   * @param session connection to the database
   * @param deposit deposit information to store
   * @return query result status
   */
  enum GNUNET_DB_QueryStatus
  (*insert_deposit)(void *cls,
                    struct TALER_EXCHANGEDB_Session *session,
                    const struct TALER_EXCHANGEDB_Deposit *deposit);


  /**
   * Insert information about refunded coin into the database.
   *
   * @param cls the @e cls of this struct with the plugin-specific state
   * @param session connection to the database
   * @param refund refund information to store
   * @return query result status
   */
  enum GNUNET_DB_QueryStatus
  (*insert_refund)(void *cls,
                   struct TALER_EXCHANGEDB_Session *session,
                   const struct TALER_EXCHANGEDB_Refund *refund);


  /**
   * Select refunds by @a coin_pub, @a merchant_pub and @a h_contract.
   *
   * @param cls closure of plugin
   * @param session database handle to use
   * @param coin_pub coin to get refunds for
   * @param merchant_pub merchant to get refunds for
   * @param h_contract_pub contract (hash) to get refunds for
   * @param cb function to call for each refund found
   * @param cb_cls closure for @a cb
   * @return query result status
   */
  enum GNUNET_DB_QueryStatus
  (*select_refunds_by_coin)(void *cls,
                            struct TALER_EXCHANGEDB_Session *session,
                            const struct TALER_CoinSpendPublicKeyP *coin_pub,
                            const struct TALER_MerchantPublicKeyP *merchant_pub,
                            const struct GNUNET_HashCode *h_contract,
                            TALER_EXCHANGEDB_RefundCoinCallback cb,
                            void *cb_cls);


  /**
   * Mark a deposit as tiny, thereby declaring that it cannot be executed by
   * itself (only included in a larger aggregation) and should no longer be
   * returned by @e iterate_ready_deposits()
   *
   * @param cls the @e cls of this struct with the plugin-specific state
   * @param session connection to the database
   * @param deposit_rowid identifies the deposit row to modify
   * @return query result status
   */
  enum GNUNET_DB_QueryStatus
  (*mark_deposit_tiny)(void *cls,
                       struct TALER_EXCHANGEDB_Session *session,
                       uint64_t rowid);


  /**
   * Test if a deposit was marked as done, thereby declaring that it
   * cannot be refunded anymore.
   *
   * @param cls the @e cls of this struct with the plugin-specific state
   * @param session connection to the database
   * @param coin_pub the coin to check for deposit
   * @param merchant_pub merchant to receive the deposit
   * @param h_contract_terms contract terms of the deposit
   * @param h_wire hash of the merchant's wire details
   * @return #GNUNET_DB_STATUS_SUCCESS_ONE_RESULT if is is marked done,
   *         #GNUNET_DB_STATUS_SUCCESS_NO_RESULTS if not,
   *         otherwise transaction error status (incl. deposit unknown)
   */
  enum GNUNET_DB_QueryStatus
  (*test_deposit_done)(void *cls,
                       struct TALER_EXCHANGEDB_Session *session,
                       const struct TALER_CoinSpendPublicKeyP *coin_pub,
                       const struct TALER_MerchantPublicKeyP *merchant_pub,
                       const struct GNUNET_HashCode *h_contract_terms,
                       const struct GNUNET_HashCode *h_wire);


  /**
   * Mark a deposit as done, thereby declaring that it cannot be
   * executed at all anymore, and should no longer be returned by
   * @e iterate_ready_deposits() or @e iterate_matching_deposits().
   *
   * @param cls the @e cls of this struct with the plugin-specific state
   * @param session connection to the database
   * @param deposit_rowid identifies the deposit row to modify
   * @return query result status
   */
  enum GNUNET_DB_QueryStatus
  (*mark_deposit_done)(void *cls,
                       struct TALER_EXCHANGEDB_Session *session,
                       uint64_t rowid);


  /**
   * Obtain information about deposits that are ready to be executed.
   * Such deposits must not be marked as "tiny" or "done", and the
   * execution time and refund deadlines must both be in the past.
   *
   * @param cls the @e cls of this struct with the plugin-specific state
   * @param session connection to the database
   * @param deposit_cb function to call for ONE such deposit
   * @param deposit_cb_cls closure for @a deposit_cb
   * @return transaction status code
   */
  enum GNUNET_DB_QueryStatus
  (*get_ready_deposit)(void *cls,
                       struct TALER_EXCHANGEDB_Session *session,
                       TALER_EXCHANGEDB_DepositIterator deposit_cb,
                       void *deposit_cb_cls);


/**
 * Maximum number of results we return from iterate_matching_deposits().
 *
 * Limit on the number of transactions we aggregate at once.  Note
 * that the limit must be big enough to ensure that when transactions
 * of the smallest possible unit are aggregated, they do surpass the
 * "tiny" threshold beyond which we never trigger a wire transaction!
 */
#define TALER_EXCHANGEDB_MATCHING_DEPOSITS_LIMIT 10000

  /**
   * Obtain information about other pending deposits for the same
   * destination.  Those deposits must not already be "done".
   *
   * @param cls the @e cls of this struct with the plugin-specific state
   * @param session connection to the database
   * @param h_wire destination of the wire transfer
   * @param merchant_pub public key of the merchant
   * @param deposit_cb function to call for each deposit
   * @param deposit_cb_cls closure for @a deposit_cb
   * @param limit maximum number of matching deposits to return; should
   *        be #TALER_EXCHANGEDB_MATCHING_DEPOSITS_LIMIT, larger values
   *        are not supported, smaller values would be inefficient.
   * @return number of rows processed, 0 if none exist,
   *         transaction status code on error
   */
  enum GNUNET_DB_QueryStatus
  (*iterate_matching_deposits)(void *cls,
                               struct TALER_EXCHANGEDB_Session *session,
                               const struct GNUNET_HashCode *h_wire,
                               const struct
                               TALER_MerchantPublicKeyP *merchant_pub,
                               TALER_EXCHANGEDB_DepositIterator deposit_cb,
                               void *deposit_cb_cls,
                               uint32_t limit);


  /**
   * Store new melt commitment data.
   *
   * @param cls the @e cls of this struct with the plugin-specific state
   * @param session database handle to use
   * @param refresh_session operational data to store
   * @return query status for the transaction
   */
  enum GNUNET_DB_QueryStatus
  (*insert_melt)(void *cls,
                 struct TALER_EXCHANGEDB_Session *session,
                 const struct TALER_EXCHANGEDB_Refresh *refresh_session);


  /**
   * Lookup melt commitment data under the given @a rc.
   *
   * @param cls the @e cls of this struct with the plugin-specific state
   * @param session database handle to use
   * @param rc commitment to use for the lookup
   * @param[out] melt where to store the result; note that
   *             melt->session.coin.denom_sig will be set to NULL
   *             and is not fetched by this routine (as it is not needed by the client)
   * @return transaction status
   */
  enum GNUNET_DB_QueryStatus
  (*get_melt)(void *cls,
              struct TALER_EXCHANGEDB_Session *session,
              const struct TALER_RefreshCommitmentP *rc,
              struct TALER_EXCHANGEDB_Melt *melt);


  /**
   * Lookup noreveal index of a previous melt operation under the given
   * @a rc.
   *
   * @param cls the `struct PostgresClosure` with the plugin-specific state
   * @param session database handle to use
   * @param rc commitment hash to use to locate the operation
   * @param[out] noreveal_index returns the "gamma" value selected by the
   *             exchange which is the index of the transfer key that is
   *             not to be revealed to the exchange
   * @return transaction status
   */
  enum GNUNET_DB_QueryStatus
  (*get_melt_index)(void *cls,
                    struct TALER_EXCHANGEDB_Session *session,
                    const struct TALER_RefreshCommitmentP *rc,
                    uint32_t *noreveal_index);


  /**
   * Store in the database which coin(s) the wallet wanted to create
   * in a given refresh operation and all of the other information
   * we learned or created in the reveal step.
   *
   * @param cls the @e cls of this struct with the plugin-specific state
   * @param session database connection
   * @param rc identify commitment and thus refresh operation
   * @param num_rrcs number of coins to generate, size of the @a rrcs array
   * @param rrcs information about the new coins
   * @param num_tprivs number of entries in @a tprivs, should be #TALER_CNC_KAPPA - 1
   * @param tprivs transfer private keys to store
   * @param tp public key to store
   * @return query status for the transaction
   */
  enum GNUNET_DB_QueryStatus
  (*insert_refresh_reveal)(void *cls,
                           struct TALER_EXCHANGEDB_Session *session,
                           const struct TALER_RefreshCommitmentP *rc,
                           uint32_t num_rrcs,
                           const struct
                           TALER_EXCHANGEDB_RefreshRevealedCoin *rrcs,
                           unsigned int num_tprivs,
                           const struct TALER_TransferPrivateKeyP *tprivs,
                           const struct TALER_TransferPublicKeyP *tp);


  /**
   * Lookup in the database for the @a num_newcoins coins that we
   * created in the given refresh operation.
   *
   * @param cls the @e cls of this struct with the plugin-specific state
   * @param session database connection
   * @param rc identify commitment and thus refresh operation
   * @param cb function to call with the results
   * @param cb_cls closure for @a cb
   * @return transaction status
   */
  enum GNUNET_DB_QueryStatus
  (*get_refresh_reveal)(void *cls,
                        struct TALER_EXCHANGEDB_Session *session,
                        const struct TALER_RefreshCommitmentP *rc,
                        TALER_EXCHANGEDB_RefreshCallback cb,
                        void *cb_cls);


  /**
   * Obtain shared secret and transfer public key from the public key of
   * the coin.  This information and the link information returned by
   * @e get_link_data_list() enable the owner of an old coin to determine
   * the private keys of the new coins after the melt.
   *
   * @param cls the @e cls of this struct with the plugin-specific state
   * @param session database connection
   * @param coin_pub public key of the coin
   * @param ldc function to call for each session the coin was melted into
   * @param ldc_cls closure for @a tdc
   * @return statement execution status
   */
  enum GNUNET_DB_QueryStatus
  (*get_link_data)(void *cls,
                   struct TALER_EXCHANGEDB_Session *session,
                   const struct TALER_CoinSpendPublicKeyP *coin_pub,
                   TALER_EXCHANGEDB_LinkCallback ldc,
                   void *tdc_cls);


  /**
   * Compile a list of all (historic) transactions performed
   * with the given coin (melt, refund, recoup and deposit operations).
   *
   * @param cls the @e cls of this struct with the plugin-specific state
   * @param session database connection
   * @param coin_pub coin to investigate
   * @param include_recoup include recoup transactions of the coin?
   * @param[out] tlp set to list of transactions, NULL if coin is fresh
   * @return database transaction status
   */
  enum GNUNET_DB_QueryStatus
  (*get_coin_transactions)(void *cls,
                           struct TALER_EXCHANGEDB_Session *session,
                           const struct TALER_CoinSpendPublicKeyP *coin_pub,
                           int include_recoup,
                           struct TALER_EXCHANGEDB_TransactionList **tlp);


  /**
   * Free linked list of transactions.
   *
   * @param cls the @e cls of this struct with the plugin-specific state
   * @param list list to free
   */
  void
  (*free_coin_transaction_list) (void *cls,
                                 struct TALER_EXCHANGEDB_TransactionList *list);


  /**
   * Lookup the list of Taler transactions that was aggregated
   * into a wire transfer by the respective @a raw_wtid.
   *
   * @param cls the @e cls of this struct with the plugin-specific state
   * @param session database connection
   * @param wtid the raw wire transfer identifier we used
   * @param cb function to call on each transaction found
   * @param cb_cls closure for @a cb
   * @return query status of the transaction
   */
  enum GNUNET_DB_QueryStatus
  (*lookup_wire_transfer)(void *cls,
                          struct TALER_EXCHANGEDB_Session *session,
                          const struct TALER_WireTransferIdentifierRawP *wtid,
                          TALER_EXCHANGEDB_AggregationDataCallback cb,
                          void *cb_cls);


  /**
   * Try to find the wire transfer details for a deposit operation.
   * If we did not execute the deposit yet, return when it is supposed
   * to be executed.
   *
   * @param cls closure
   * @param session database connection
   * @param h_contract_terms hash of the proposal data
   * @param h_wire hash of merchant wire details
   * @param coin_pub public key of deposited coin
   * @param merchant_pub merchant public key
   * @param cb function to call with the result
   * @param cb_cls closure to pass to @a cb
   * @return transaction status code
   */
  enum GNUNET_DB_QueryStatus
  (*wire_lookup_deposit_wtid)(void *cls,
                              struct TALER_EXCHANGEDB_Session *session,
                              const struct GNUNET_HashCode *h_contract_terms,
                              const struct GNUNET_HashCode *h_wire,
                              const struct TALER_CoinSpendPublicKeyP *coin_pub,
                              const struct
                              TALER_MerchantPublicKeyP *merchant_pub,
                              TALER_EXCHANGEDB_WireTransferByCoinCallback cb,
                              void *cb_cls);


  /**
   * Function called to insert aggregation information into the DB.
   *
   * @param cls closure
   * @param session database connection
   * @param wtid the raw wire transfer identifier we used
   * @param deposit_serial_id row in the deposits table for which this is aggregation data
   * @return transaction status code
   */
  enum GNUNET_DB_QueryStatus
  (*insert_aggregation_tracking)(void *cls,
                                 struct TALER_EXCHANGEDB_Session *session,
                                 const struct
                                 TALER_WireTransferIdentifierRawP *wtid,
                                 unsigned long long deposit_serial_id);


  /**
   * Insert wire transfer fee into database.
   *
   * @param cls closure
   * @param session database connection
   * @param wire_method which wire method is the fee about?
   * @param start_date when does the fee go into effect
   * @param end_date when does the fee end being valid
   * @param wire_fee how high is the wire transfer fee
   * @param closing_fee how high is the closing fee
   * @param master_sig signature over the above by the exchange master key
   * @return transaction status code
   */
  enum GNUNET_DB_QueryStatus
  (*insert_wire_fee)(void *cls,
                     struct TALER_EXCHANGEDB_Session *session,
                     const char *wire_method,
                     struct GNUNET_TIME_Absolute start_date,
                     struct GNUNET_TIME_Absolute end_date,
                     const struct TALER_Amount *wire_fee,
                     const struct TALER_Amount *closing_fee,
                     const struct TALER_MasterSignatureP *master_sig);


  /**
   * Obtain wire fee from database.
   *
   * @param cls closure
   * @param session database connection
   * @param type type of wire transfer the fee applies for
   * @param date for which date do we want the fee?
   * @param[out] start_date when does the fee go into effect
   * @param[out] end_date when does the fee end being valid
   * @param[out] wire_fee how high is the wire transfer fee
   * @param[out] closing_fee how high is the closing fee
   * @param[out] master_sig signature over the above by the exchange master key
   * @return query status of the transaction
   */
  enum GNUNET_DB_QueryStatus
  (*get_wire_fee)(void *cls,
                  struct TALER_EXCHANGEDB_Session *session,
                  const char *type,
                  struct GNUNET_TIME_Absolute date,
                  struct GNUNET_TIME_Absolute *start_date,
                  struct GNUNET_TIME_Absolute *end_date,
                  struct TALER_Amount *wire_fee,
                  struct TALER_Amount *closing_fee,
                  struct TALER_MasterSignatureP *master_sig);


  /**
   * Obtain information about expired reserves and their
   * remaining balances.
   *
   * @param cls closure of the plugin
   * @param session database connection
   * @param now timestamp based on which we decide expiration
   * @param rec function to call on expired reserves
   * @param rec_cls closure for @a rec
   * @return transaction status
   */
  enum GNUNET_DB_QueryStatus
  (*get_expired_reserves)(void *cls,
                          struct TALER_EXCHANGEDB_Session *session,
                          struct GNUNET_TIME_Absolute now,
                          TALER_EXCHANGEDB_ReserveExpiredCallback rec,
                          void *rec_cls);


  /**
   * Insert reserve close operation into database.
   *
   * @param cls closure
   * @param session database connection
   * @param reserve_pub which reserve is this about?
   * @param execution_date when did we perform the transfer?
   * @param receiver_account to which account do we transfer, in payto://-format
   * @param wtid identifier for the wire transfer
   * @param amount_with_fee amount we charged to the reserve
   * @param closing_fee how high is the closing fee
   * @return transaction status code
   */
  enum GNUNET_DB_QueryStatus
  (*insert_reserve_closed)(void *cls,
                           struct TALER_EXCHANGEDB_Session *session,
                           const struct TALER_ReservePublicKeyP *reserve_pub,
                           struct GNUNET_TIME_Absolute execution_date,
                           const char *receiver_account,
                           const struct TALER_WireTransferIdentifierRawP *wtid,
                           const struct TALER_Amount *amount_with_fee,
                           const struct TALER_Amount *closing_fee);


  /**
   * Function called to insert wire transfer commit data into the DB.
   *
   * @param cls closure
   * @param session database connection
   * @param type type of the wire transfer (i.e. "iban")
   * @param buf buffer with wire transfer preparation data
   * @param buf_size number of bytes in @a buf
   * @return query status code
   */
  enum GNUNET_DB_QueryStatus
  (*wire_prepare_data_insert)(void *cls,
                              struct TALER_EXCHANGEDB_Session *session,
                              const char *type,
                              const char *buf,
                              size_t buf_size);


  /**
   * Function called to mark wire transfer commit data as finished.
   *
   * @param cls closure
   * @param session database connection
   * @param rowid which entry to mark as finished
   * @return transaction status code
   */
  enum GNUNET_DB_QueryStatus
  (*wire_prepare_data_mark_finished)(void *cls,
                                     struct TALER_EXCHANGEDB_Session *session,
                                     uint64_t rowid);


  /**
   * Function called to get an unfinished wire transfer
   * preparation data. Fetches at most one item.
   *
   * @param cls closure
   * @param session database connection
   * @param cb function to call for ONE unfinished item
   * @param cb_cls closure for @a cb
   * @return transaction status code
   */
  enum GNUNET_DB_QueryStatus
  (*wire_prepare_data_get)(void *cls,
                           struct TALER_EXCHANGEDB_Session *session,
                           TALER_EXCHANGEDB_WirePreparationIterator cb,
                           void *cb_cls);


  /**
   * Start a transaction where we transiently violate the foreign
   * constraints on the "wire_out" table as we insert aggregations
   * and only add the wire transfer out at the end.
   *
   * @param cls the @e cls of this struct with the plugin-specific state
   * @param session connection to use
   * @return #GNUNET_OK on success
   */
  int
  (*start_deferred_wire_out) (void *cls,
                              struct TALER_EXCHANGEDB_Session *session);


  /**
   * Store information about an outgoing wire transfer that was executed.
   *
   * @param cls closure
   * @param session database connection
   * @param date time of the wire transfer
   * @param wtid subject of the wire transfer
   * @param wire_account details about the receiver account of the wire transfer,
   *        including 'url' in payto://-format
   * @param amount amount that was transmitted
   * @param exchange_account_section configuration section of the exchange specifying the
   *        exchange's bank account being used
   * @return transaction status code
   */
  enum GNUNET_DB_QueryStatus
  (*store_wire_transfer_out)(void *cls,
                             struct TALER_EXCHANGEDB_Session *session,
                             struct GNUNET_TIME_Absolute date,
                             const struct
                             TALER_WireTransferIdentifierRawP *wtid,
                             const json_t *wire_account,
                             const char *exchange_account_section,
                             const struct TALER_Amount *amount);


  /**
   * Function called to perform "garbage collection" on the
   * database, expiring records we no longer require.
   *
   * @param cls closure
   * @return #GNUNET_OK on success,
   *         #GNUNET_SYSERR on DB errors
   */
  int
  (*gc) (void *cls);


  /**
   * Select deposits above @a serial_id in monotonically increasing
   * order.
   *
   * @param cls closure
   * @param session database connection
   * @param serial_id highest serial ID to exclude (select strictly larger)
   * @param cb function to call on each result
   * @param cb_cls closure for @a cb
   * @return transaction status code
   */
  enum GNUNET_DB_QueryStatus
  (*select_deposits_above_serial_id)(void *cls,
                                     struct TALER_EXCHANGEDB_Session *session,
                                     uint64_t serial_id,
                                     TALER_EXCHANGEDB_DepositCallback cb,
                                     void *cb_cls);

  /**
   * Select refresh sessions above @a serial_id in monotonically increasing
   * order.
   *
   * @param cls closure
   * @param session database connection
   * @param serial_id highest serial ID to exclude (select strictly larger)
   * @param cb function to call on each result
   * @param cb_cls closure for @a cb
   * @return transaction status code
   */
  enum GNUNET_DB_QueryStatus
  (*select_refreshes_above_serial_id)(void *cls,
                                      struct TALER_EXCHANGEDB_Session *session,
                                      uint64_t serial_id,
                                      TALER_EXCHANGEDB_RefreshesCallback cb,
                                      void *cb_cls);


  /**
   * Select refunds above @a serial_id in monotonically increasing
   * order.
   *
   * @param cls closure
   * @param session database connection
   * @param serial_id highest serial ID to exclude (select strictly larger)
   * @param cb function to call on each result
   * @param cb_cls closure for @a cb
   * @return transaction status code
   */
  enum GNUNET_DB_QueryStatus
  (*select_refunds_above_serial_id)(void *cls,
                                    struct TALER_EXCHANGEDB_Session *session,
                                    uint64_t serial_id,
                                    TALER_EXCHANGEDB_RefundCallback cb,
                                    void *cb_cls);


  /**
   * Select inbound wire transfers into reserves_in above @a serial_id
   * in monotonically increasing order.
   *
   * @param cls closure
   * @param session database connection
   * @param serial_id highest serial ID to exclude (select strictly larger)
   * @param cb function to call on each result
   * @param cb_cls closure for @a cb
   * @return transaction status code
   */
  enum GNUNET_DB_QueryStatus
  (*select_reserves_in_above_serial_id)(void *cls,
                                        struct TALER_EXCHANGEDB_Session *session,
                                        uint64_t serial_id,
                                        TALER_EXCHANGEDB_ReserveInCallback cb,
                                        void *cb_cls);

  /**
   * Select inbound wire transfers into reserves_in above @a serial_id
   * in monotonically increasing order by @a account_name.
   *
   * @param cls closure
   * @param session database connection
   * @param account_name name of the account for which we do the selection
   * @param serial_id highest serial ID to exclude (select strictly larger)
   * @param cb function to call on each result
   * @param cb_cls closure for @a cb
   * @return transaction status code
   */
  enum GNUNET_DB_QueryStatus
  (*select_reserves_in_above_serial_id_by_account)(void *cls,
                                                   struct
                                                   TALER_EXCHANGEDB_Session *
                                                   session,
                                                   const char *account_name,
                                                   uint64_t serial_id,
                                                   TALER_EXCHANGEDB_ReserveInCallback
                                                   cb,
                                                   void *cb_cls);

  /**
   * Select withdraw operations from reserves_out above @a serial_id
   * in monotonically increasing order.
   *
   * @param cls closure
   * @param session database connection
   * @param account_name name of the account for which we do the selection
   * @param serial_id highest serial ID to exclude (select strictly larger)
   * @param cb function to call on each result
   * @param cb_cls closure for @a cb
   * @return transaction status code
   */
  enum GNUNET_DB_QueryStatus
  (*select_withdrawals_above_serial_id)(void *cls,
                                        struct TALER_EXCHANGEDB_Session *
                                        session,
                                        uint64_t serial_id,
                                        TALER_EXCHANGEDB_WithdrawCallback cb,
                                        void *cb_cls);

  /**
   * Function called to select outgoing wire transfers the exchange
   * executed, ordered by serial ID (monotonically increasing).
   *
   * @param cls closure
   * @param session database connection
   * @param serial_id lowest serial ID to include (select larger or equal)
   * @param cb function to call for ONE unfinished item
   * @param cb_cls closure for @a cb
   * @return transaction status code
   */
  enum GNUNET_DB_QueryStatus
  (*select_wire_out_above_serial_id)(void *cls,
                                     struct TALER_EXCHANGEDB_Session *session,
                                     uint64_t serial_id,
                                     TALER_EXCHANGEDB_WireTransferOutCallback cb,
                                     void *cb_cls);

  /**
   * Function called to select outgoing wire transfers the exchange
   * executed, ordered by serial ID (monotonically increasing).
   *
   * @param cls closure
   * @param session database connection
   * @param account_name name to select by
   * @param serial_id lowest serial ID to include (select larger or equal)
   * @param cb function to call for ONE unfinished item
   * @param cb_cls closure for @a cb
   * @return transaction status code
   */
  enum GNUNET_DB_QueryStatus
  (*select_wire_out_above_serial_id_by_account)(void *cls,
                                                struct TALER_EXCHANGEDB_Session
                                                *session,
                                                const char *account_name,
                                                uint64_t serial_id,
                                                TALER_EXCHANGEDB_WireTransferOutCallback
                                                cb,
                                                void *cb_cls);


  /**
   * Function called to select recoup requests the exchange
   * received, ordered by serial ID (monotonically increasing).
   *
   * @param cls closure
   * @param session database connection
   * @param serial_id lowest serial ID to include (select larger or equal)
   * @param cb function to call for ONE unfinished item
   * @param cb_cls closure for @a cb
   * @return transaction status code
   */
  enum GNUNET_DB_QueryStatus
  (*select_recoup_above_serial_id)(void *cls,
                                   struct TALER_EXCHANGEDB_Session *session,
                                   uint64_t serial_id,
                                   TALER_EXCHANGEDB_RecoupCallback cb,
                                   void *cb_cls);


  /**
   * Function called to select recoup requests the exchange received for
   * refreshed coins, ordered by serial ID (monotonically increasing).
   *
   * @param cls closure
   * @param session database connection
   * @param serial_id lowest serial ID to include (select larger or equal)
   * @param cb function to call for ONE unfinished item
   * @param cb_cls closure for @a cb
   * @return transaction status code
   */
  enum GNUNET_DB_QueryStatus
  (*select_recoup_refresh_above_serial_id)(void *cls,
                                           struct TALER_EXCHANGEDB_Session *
                                           session,
                                           uint64_t serial_id,
                                           TALER_EXCHANGEDB_RecoupRefreshCallback
                                           cb,
                                           void *cb_cls);


  /**
   * Function called to select reserve close operations the aggregator
   * triggered, ordered by serial ID (monotonically increasing).
   *
   * @param cls closure
   * @param session database connection
   * @param serial_id lowest serial ID to include (select larger or equal)
   * @param cb function to call
   * @param cb_cls closure for @a cb
   * @return transaction status code
   */
  enum GNUNET_DB_QueryStatus
  (*select_reserve_closed_above_serial_id)(void *cls,
                                           struct TALER_EXCHANGEDB_Session *
                                           session,
                                           uint64_t serial_id,
                                           TALER_EXCHANGEDB_ReserveClosedCallback
                                           cb,
                                           void *cb_cls);


  /**
   * Function called to add a request for an emergency recoup for a
   * coin.  The funds are to be added back to the reserve.
   *
   * @param cls closure
   * @param session database connection
   * @param reserve_pub public key of the reserve that is being refunded
   * @param coin public information about a coin
   * @param coin_sig signature of the coin of type #TALER_SIGNATURE_WALLET_COIN_RECOUP
   * @param coin_blind blinding key of the coin
   * @param h_blind_ev blinded envelope, as calculated by the exchange
   * @param amount total amount to be paid back
   * @param h_blind_ev hash of the blinded coin's envelope (must match reserves_out entry)
   * @param timestamp the timestamp to store
   * @return transaction result status
   */
  enum GNUNET_DB_QueryStatus
  (*insert_recoup_request)(void *cls,
                           struct TALER_EXCHANGEDB_Session *session,
                           const struct TALER_ReservePublicKeyP *reserve_pub,
                           const struct TALER_CoinPublicInfo *coin,
                           const struct TALER_CoinSpendSignatureP *coin_sig,
                           const struct
                           TALER_DenominationBlindingKeyP *coin_blind,
                           const struct TALER_Amount *amount,
                           const struct GNUNET_HashCode *h_blind_ev,
                           struct GNUNET_TIME_Absolute timestamp);


  /**
   * Function called to add a request for an emergency recoup for a
   * refreshed coin.  The funds are to be added back to the original coin.
   *
   * @param cls closure
   * @param session database connection
   * @param coin public information about the refreshed coin
   * @param coin_sig signature of the coin of type #TALER_SIGNATURE_WALLET_COIN_RECOUP
   * @param coin_blind blinding key of the coin
   * @param h_blind_ev blinded envelope, as calculated by the exchange
   * @param amount total amount to be paid back
   * @param h_blind_ev hash of the blinded coin's envelope (must match reserves_out entry)
   * @param timestamp a timestamp to store
   * @return transaction result status
   */
  enum GNUNET_DB_QueryStatus
  (*insert_recoup_refresh_request)(void *cls,
                                   struct TALER_EXCHANGEDB_Session *session,
                                   const struct TALER_CoinPublicInfo *coin,
                                   const struct
                                   TALER_CoinSpendSignatureP *coin_sig,
                                   const struct
                                   TALER_DenominationBlindingKeyP *coin_blind,
                                   const struct TALER_Amount *amount,
                                   const struct GNUNET_HashCode *h_blind_ev,
                                   struct GNUNET_TIME_Absolute timestamp);


  /**
   * Obtain information about which reserve a coin was generated
   * from given the hash of the blinded coin.
   *
   * @param cls closure
   * @param session a session
   * @param h_blind_ev hash of the blinded coin
   * @param[out] reserve_pub set to information about the reserve (on success only)
   * @return transaction status code
   */
  enum GNUNET_DB_QueryStatus
  (*get_reserve_by_h_blind)(void *cls,
                            struct TALER_EXCHANGEDB_Session *session,
                            const struct GNUNET_HashCode *h_blind_ev,
                            struct TALER_ReservePublicKeyP *reserve_pub);


  /**
   * Obtain information about which old coin a coin was refreshed
   * given the hash of the blinded (fresh) coin.
   *
   * @param cls closure
   * @param session a session
   * @param h_blind_ev hash of the blinded coin
   * @param[out] old_coin_pub set to information about the old coin (on success only)
   * @return transaction status code
   */
  enum GNUNET_DB_QueryStatus
  (*get_old_coin_by_h_blind)(void *cls,
                             struct TALER_EXCHANGEDB_Session *session,
                             const struct GNUNET_HashCode *h_blind_ev,
                             struct TALER_CoinSpendPublicKeyP *old_coin_pub);


  /**
   * Store information that a denomination key was revoked
   * in the database.
   *
   * @param cls closure
   * @param session a session
   * @param denom_pub_hash hash of the revoked denomination key
   * @param master_sig signature affirming the revocation
   * @return transaction status code
   */
  enum GNUNET_DB_QueryStatus
  (*insert_denomination_revocation)(void *cls,
                                    struct TALER_EXCHANGEDB_Session *session,
                                    const struct
                                    GNUNET_HashCode *denom_pub_hash,
                                    const struct
                                    TALER_MasterSignatureP *master_sig);


  /**
   * Obtain information about a denomination key's revocation from
   * the database.
   *
   * @param cls closure
   * @param session a session
   * @param denom_pub_hash hash of the revoked denomination key
   * @param[out] master_sig signature affirming the revocation
   * @param[out] rowid row where the information is stored
   * @return transaction status code
   */
  enum GNUNET_DB_QueryStatus
  (*get_denomination_revocation)(void *cls,
                                 struct TALER_EXCHANGEDB_Session *session,
                                 const struct GNUNET_HashCode *denom_pub_hash,
                                 struct TALER_MasterSignatureP *master_sig,
                                 uint64_t *rowid);


  /**
   * Select all of those deposits in the database for which we do
   * not have a wire transfer (or a refund) and which should have
   * been deposited between @a start_date and @a end_date.
   *
   * @param cls closure
   * @param session a session
   * @param start_date lower bound on the requested wire execution date
   * @param end_date upper bound on the requested wire execution date
   * @param cb function to call on all such deposits
   * @param cb_cls closure for @a cb
   * @return transaction status code
   */
  enum GNUNET_DB_QueryStatus
  (*select_deposits_missing_wire)(void *cls,
                                  struct TALER_EXCHANGEDB_Session *session,
                                  struct GNUNET_TIME_Absolute start_date,
                                  struct GNUNET_TIME_Absolute end_date,
                                  TALER_EXCHANGEDB_WireMissingCallback cb,
                                  void *cb_cls);

};

#endif /* _TALER_EXCHANGE_DB_H */