~drizzle-trunk/drizzle/development

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
/* Copyright (C) 2000-2006 MySQL AB

   This program 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; version 2 of the License.

   This program 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 this program; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */

/**
  @defgroup Semantic_Analysis Semantic Analysis
*/

/* YACC and LEX Definitions */

/* These may not be declared yet */
class Table_ident;
class sql_exchange;
class LEX_COLUMN;
class st_alter_tablespace;

#ifdef MYSQL_SERVER
/*
  The following hack is needed because mysql_yacc.cc does not define
  YYSTYPE before including this file
*/

#include "set_var.h"

#ifdef MYSQL_YACC
#define LEX_YYSTYPE void *
#else
#if MYSQL_LEX
#include "lex_symbol.h"
#include "sql_yacc.h"
#define LEX_YYSTYPE YYSTYPE *
#else
#define LEX_YYSTYPE void *
#endif
#endif
#endif

/*
  When a command is added here, be sure it's also added in mysqld.cc
  in "struct show_var_st status_vars[]= {" ...

  If the command returns a result set or is not allowed in stored
  functions or triggers, please also make sure that
  sp_get_flags_for_command (sp_head.cc) returns proper flags for the
  added SQLCOM_.
*/

enum enum_sql_command {
  SQLCOM_SELECT, SQLCOM_CREATE_TABLE, SQLCOM_CREATE_INDEX, SQLCOM_ALTER_TABLE,
  SQLCOM_UPDATE, SQLCOM_INSERT, SQLCOM_INSERT_SELECT,
  SQLCOM_DELETE, SQLCOM_TRUNCATE, SQLCOM_DROP_TABLE, SQLCOM_DROP_INDEX,
  SQLCOM_SHOW_DATABASES, SQLCOM_SHOW_TABLES, SQLCOM_SHOW_FIELDS,
  SQLCOM_SHOW_KEYS, SQLCOM_SHOW_VARIABLES, SQLCOM_SHOW_STATUS,
  SQLCOM_SHOW_ENGINE_LOGS, SQLCOM_SHOW_ENGINE_STATUS, SQLCOM_SHOW_ENGINE_MUTEX,
  SQLCOM_SHOW_PROCESSLIST, SQLCOM_SHOW_MASTER_STAT, SQLCOM_SHOW_SLAVE_STAT,
  SQLCOM_SHOW_CREATE, SQLCOM_SHOW_CHARSETS,
  SQLCOM_SHOW_COLLATIONS, SQLCOM_SHOW_CREATE_DB, SQLCOM_SHOW_TABLE_STATUS,
  SQLCOM_LOAD,SQLCOM_SET_OPTION,SQLCOM_LOCK_TABLES,SQLCOM_UNLOCK_TABLES,
  SQLCOM_CHANGE_DB, SQLCOM_CREATE_DB, SQLCOM_DROP_DB, SQLCOM_ALTER_DB,
  SQLCOM_REPAIR, SQLCOM_REPLACE, SQLCOM_REPLACE_SELECT,
  SQLCOM_CREATE_FUNCTION, SQLCOM_DROP_FUNCTION,
  SQLCOM_OPTIMIZE, SQLCOM_CHECK,
  SQLCOM_ASSIGN_TO_KEYCACHE, SQLCOM_PRELOAD_KEYS,
  SQLCOM_FLUSH, SQLCOM_KILL, SQLCOM_ANALYZE,
  SQLCOM_ROLLBACK, SQLCOM_ROLLBACK_TO_SAVEPOINT,
  SQLCOM_COMMIT, SQLCOM_SAVEPOINT, SQLCOM_RELEASE_SAVEPOINT,
  SQLCOM_SLAVE_START, SQLCOM_SLAVE_STOP,
  SQLCOM_BEGIN, SQLCOM_CHANGE_MASTER,
  SQLCOM_RENAME_TABLE,  
  SQLCOM_RESET, SQLCOM_PURGE, SQLCOM_PURGE_BEFORE, SQLCOM_SHOW_BINLOGS,
  SQLCOM_SHOW_OPEN_TABLES,
  SQLCOM_SHOW_SLAVE_HOSTS, SQLCOM_DELETE_MULTI, SQLCOM_UPDATE_MULTI,
  SQLCOM_SHOW_BINLOG_EVENTS, SQLCOM_SHOW_NEW_MASTER,
  SQLCOM_SHOW_WARNS, SQLCOM_EMPTY_QUERY, SQLCOM_SHOW_ERRORS,
  SQLCOM_SHOW_STORAGE_ENGINES,
  SQLCOM_CHECKSUM,
  SQLCOM_PREPARE, SQLCOM_EXECUTE, SQLCOM_DEALLOCATE_PREPARE,
  SQLCOM_XA_START, SQLCOM_XA_END, SQLCOM_XA_PREPARE,
  SQLCOM_XA_COMMIT, SQLCOM_XA_ROLLBACK, SQLCOM_XA_RECOVER,
  SQLCOM_ALTER_TABLESPACE,
  SQLCOM_SHOW_AUTHORS, SQLCOM_BINLOG_BASE64_EVENT,
  SQLCOM_SHOW_PLUGINS,
  SQLCOM_SHOW_CONTRIBUTORS,
  SQLCOM_ALTER_DB_UPGRADE,
  SQLCOM_SHOW_ARCHIVE,

  /*
    When a command is added here, be sure it's also added in mysqld.cc
    in "struct show_var_st status_vars[]= {" ...
  */
  /* This should be the last !!! */
  SQLCOM_END
};

// describe/explain types
#define DESCRIBE_NORMAL		1
#define DESCRIBE_EXTENDED	2

#ifdef MYSQL_SERVER

enum enum_sp_data_access
{
  SP_DEFAULT_ACCESS= 0,
  SP_CONTAINS_SQL,
  SP_NO_SQL,
  SP_READS_SQL_DATA,
  SP_MODIFIES_SQL_DATA
};

const LEX_STRING sp_data_access_name[]=
{
  { C_STRING_WITH_LEN("") },
  { C_STRING_WITH_LEN("CONTAINS SQL") },
  { C_STRING_WITH_LEN("NO SQL") },
  { C_STRING_WITH_LEN("READS SQL DATA") },
  { C_STRING_WITH_LEN("MODIFIES SQL DATA") }
};

#define DERIVED_NONE	0
#define DERIVED_SUBQUERY	1

enum enum_drop_mode
{
  DROP_DEFAULT, // mode is not specified
  DROP_CASCADE, // CASCADE option
  DROP_RESTRICT // RESTRICT option
};

typedef List<Item> List_item;

/* SERVERS CACHE CHANGES */
typedef struct st_lex_server_options
{
  long port;
  uint server_name_length;
  char *server_name, *host, *db, *username, *password, *scheme, *socket, *owner;
} LEX_SERVER_OPTIONS;

typedef struct st_lex_master_info
{
  char *host, *user, *password, *log_file_name;
  uint port, connect_retry;
  float heartbeat_period;
  ulonglong pos;
  ulong server_id;
  /*
    Enum is used for making it possible to detect if the user
    changed variable or if it should be left at old value
   */
  enum {LEX_MI_UNCHANGED, LEX_MI_DISABLE, LEX_MI_ENABLE}
    ssl, ssl_verify_server_cert, heartbeat_opt;
  char *ssl_key, *ssl_cert, *ssl_ca, *ssl_capath, *ssl_cipher;
  char *relay_log_name;
  ulong relay_log_pos;
} LEX_MASTER_INFO;


enum sub_select_type
{
  UNSPECIFIED_TYPE,UNION_TYPE, INTERSECT_TYPE,
  EXCEPT_TYPE, GLOBAL_OPTIONS_TYPE, DERIVED_TABLE_TYPE, OLAP_TYPE
};

enum olap_type 
{
  UNSPECIFIED_OLAP_TYPE, CUBE_TYPE, ROLLUP_TYPE
};

enum tablespace_op_type
{
  NO_TABLESPACE_OP, DISCARD_TABLESPACE, IMPORT_TABLESPACE
};

/* 
  String names used to print a statement with index hints.
  Keep in sync with index_hint_type.
*/
extern const char * index_hint_type_name[];
typedef uchar index_clause_map;

/*
  Bits in index_clause_map : one for each possible FOR clause in
  USE/FORCE/IGNORE INDEX index hint specification
*/
#define INDEX_HINT_MASK_JOIN  (1)
#define INDEX_HINT_MASK_GROUP (1 << 1)
#define INDEX_HINT_MASK_ORDER (1 << 2)

#define INDEX_HINT_MASK_ALL (INDEX_HINT_MASK_JOIN | INDEX_HINT_MASK_GROUP | \
                             INDEX_HINT_MASK_ORDER)

/* Single element of an USE/FORCE/IGNORE INDEX list specified as a SQL hint  */
class Index_hint : public Sql_alloc
{
public:
  /* The type of the hint : USE/FORCE/IGNORE */
  enum index_hint_type type;
  /* Where the hit applies to. A bitmask of INDEX_HINT_MASK_<place> values */
  index_clause_map clause;
  /* 
    The index name. Empty (str=NULL) name represents an empty list 
    USE INDEX () clause 
  */ 
  LEX_STRING key_name;

  Index_hint (enum index_hint_type type_arg, index_clause_map clause_arg,
              char *str, uint length) :
    type(type_arg), clause(clause_arg)
  {
    key_name.str= str;
    key_name.length= length;
  }

  void print(THD *thd, String *str);
}; 

/* 
  The state of the lex parsing for selects 
   
   master and slaves are pointers to select_lex.
   master is pointer to upper level node.
   slave is pointer to lower level node
   select_lex is a SELECT without union
   unit is container of either
     - One SELECT
     - UNION of selects
   select_lex and unit are both inherited form select_lex_node
   neighbors are two select_lex or units on the same level

   All select describing structures linked with following pointers:
   - list of neighbors (next/prev) (prev of first element point to slave
     pointer of upper structure)
     - For select this is a list of UNION's (or one element list)
     - For units this is a list of sub queries for the upper level select

   - pointer to master (master), which is
     If this is a unit
       - pointer to outer select_lex
     If this is a select_lex
       - pointer to outer unit structure for select

   - pointer to slave (slave), which is either:
     If this is a unit:
       - first SELECT that belong to this unit
     If this is a select_lex
       - first unit that belong to this SELECT (subquries or derived tables)

   - list of all select_lex (link_next/link_prev)
     This is to be used for things like derived tables creation, where we
     go through this list and create the derived tables.

   If unit contain several selects (UNION now, INTERSECT etc later)
   then it have special select_lex called fake_select_lex. It used for
   storing global parameters (like ORDER BY, LIMIT) and executing union.
   Subqueries used in global ORDER BY clause will be attached to this
   fake_select_lex, which will allow them correctly resolve fields of
   'upper' UNION and outer selects.

   For example for following query:

   select *
     from table1
     where table1.field IN (select * from table1_1_1 union
                            select * from table1_1_2)
     union
   select *
     from table2
     where table2.field=(select (select f1 from table2_1_1_1_1
                                   where table2_1_1_1_1.f2=table2_1_1.f3)
                           from table2_1_1
                           where table2_1_1.f1=table2.f2)
     union
   select * from table3;

   we will have following structure:

   select1: (select * from table1 ...)
   select2: (select * from table2 ...)
   select3: (select * from table3)
   select1.1.1: (select * from table1_1_1)
   ...

     main unit
     fake0
     select1 select2 select3
     |^^     |^
    s|||     ||master
    l|||     |+---------------------------------+
    a|||     +---------------------------------+|
    v|||master                         slave   ||
    e||+-------------------------+             ||
     V|            neighbor      |             V|
     unit1.1<+==================>unit1.2       unit2.1
     fake1.1
     select1.1.1 select 1.1.2    select1.2.1   select2.1.1
                                               |^
                                               ||
                                               V|
                                               unit2.1.1.1
                                               select2.1.1.1.1


   relation in main unit will be following:
   (bigger picture for:
      main unit
      fake0
      select1 select2 select3
   in the above picture)

         main unit
         |^^^^|fake_select_lex
         |||||+--------------------------------------------+
         ||||+--------------------------------------------+|
         |||+------------------------------+              ||
         ||+--------------+                |              ||
    slave||master         |                |              ||
         V|      neighbor |       neighbor |        master|V
         select1<========>select2<========>select3        fake0

    list of all select_lex will be following (as it will be constructed by
    parser):

    select1->select2->select3->select2.1.1->select 2.1.2->select2.1.1.1.1-+
                                                                          |
    +---------------------------------------------------------------------+
    |
    +->select1.1.1->select1.1.2

*/

/* 
    Base class for st_select_lex (SELECT_LEX) & 
    st_select_lex_unit (SELECT_LEX_UNIT)
*/
struct st_lex;
class st_select_lex;
class st_select_lex_unit;
class st_select_lex_node {
protected:
  st_select_lex_node *next, **prev,   /* neighbor list */
    *master, *slave,                  /* vertical links */
    *link_next, **link_prev;          /* list of whole SELECT_LEX */
public:

  ulonglong options;

  /*
    result of this query can't be cached, bit field, can be :
      UNCACHEABLE_DEPENDENT
      UNCACHEABLE_RAND
      UNCACHEABLE_SIDEEFFECT
      UNCACHEABLE_EXPLAIN
      UNCACHEABLE_PREPARE
  */
  uint8 uncacheable;
  enum sub_select_type linkage;
  bool no_table_names_allowed; /* used for global order by */
  bool no_error; /* suppress error message (convert it to warnings) */

  static void *operator new(size_t size)
  {
    return sql_alloc(size);
  }
  static void *operator new(size_t size, MEM_ROOT *mem_root)
  { return (void*) alloc_root(mem_root, (uint) size); }
  static void operator delete(void *ptr,size_t size) { TRASH(ptr, size); }
  static void operator delete(void *ptr, MEM_ROOT *mem_root) {}
  st_select_lex_node(): linkage(UNSPECIFIED_TYPE) {}
  virtual ~st_select_lex_node() {}
  inline st_select_lex_node* get_master() { return master; }
  virtual void init_query();
  virtual void init_select();
  void include_down(st_select_lex_node *upper);
  void include_neighbour(st_select_lex_node *before);
  void include_standalone(st_select_lex_node *sel, st_select_lex_node **ref);
  void include_global(st_select_lex_node **plink);
  void exclude();

  virtual st_select_lex_unit* master_unit()= 0;
  virtual st_select_lex* outer_select()= 0;
  virtual st_select_lex* return_after_parsing()= 0;

  virtual bool set_braces(bool value);
  virtual bool inc_in_sum_expr();
  virtual uint get_in_sum_expr();
  virtual TABLE_LIST* get_table_list();
  virtual List<Item>* get_item_list();
  virtual ulong get_table_join_options();
  virtual TABLE_LIST *add_table_to_list(THD *thd, Table_ident *table,
					LEX_STRING *alias,
					ulong table_options,
					thr_lock_type flags= TL_UNLOCK,
					List<Index_hint> *hints= 0,
                                        LEX_STRING *option= 0);
  virtual void set_lock_for_tables(thr_lock_type lock_type) {}

  friend class st_select_lex_unit;
  friend bool mysql_new_select(struct st_lex *lex, bool move_down);
private:
  void fast_exclude();
};
typedef class st_select_lex_node SELECT_LEX_NODE;

/* 
   SELECT_LEX_UNIT - unit of selects (UNION, INTERSECT, ...) group 
   SELECT_LEXs
*/
class THD;
class select_result;
class JOIN;
class select_union;
class st_select_lex_unit: public st_select_lex_node {
protected:
  TABLE_LIST result_table_list;
  select_union *union_result;
  TABLE *table; /* temporary table using for appending UNION results */

  select_result *result;
  ulonglong found_rows_for_union;
  bool saved_error;

public:
  bool  prepared, // prepare phase already performed for UNION (unit)
    optimized, // optimize phase already performed for UNION (unit)
    executed, // already executed
    cleaned;

  // list of fields which points to temporary table for union
  List<Item> item_list;
  /*
    list of types of items inside union (used for union & derived tables)
    
    Item_type_holders from which this list consist may have pointers to Field,
    pointers is valid only after preparing SELECTS of this unit and before
    any SELECT of this unit execution

    TODO:
    Possibly this member should be protected, and its direct use replaced
    by get_unit_column_types(). Check the places where it is used.
  */
  List<Item> types;
  /*
    Pointer to 'last' select or pointer to unit where stored
    global parameters for union
  */
  st_select_lex *global_parameters;
  //node on wich we should return current_select pointer after parsing subquery
  st_select_lex *return_to;
  /* LIMIT clause runtime counters */
  ha_rows select_limit_cnt, offset_limit_cnt;
  /* not NULL if unit used in subselect, point to subselect item */
  Item_subselect *item;
  /* thread handler */
  THD *thd;
  /*
    SELECT_LEX for hidden SELECT in onion which process global
    ORDER BY and LIMIT
  */
  st_select_lex *fake_select_lex;

  st_select_lex *union_distinct; /* pointer to the last UNION DISTINCT */
  bool describe; /* union exec() called for EXPLAIN */

  void init_query();
  st_select_lex_unit* master_unit();
  st_select_lex* outer_select();
  st_select_lex* first_select()
  {
    return my_reinterpret_cast(st_select_lex*)(slave);
  }
  st_select_lex_unit* next_unit()
  {
    return my_reinterpret_cast(st_select_lex_unit*)(next);
  }
  st_select_lex* return_after_parsing() { return return_to; }
  void exclude_level();
  void exclude_tree();

  /* UNION methods */
  bool prepare(THD *thd, select_result *result, ulong additional_options);
  bool exec();
  bool cleanup();
  inline void unclean() { cleaned= 0; }
  void reinit_exec_mechanism();

  void print(String *str, enum_query_type query_type);

  bool add_fake_select_lex(THD *thd);
  void init_prepare_fake_select_lex(THD *thd);
  bool change_result(select_result_interceptor *result,
                     select_result_interceptor *old_result);
  void set_limit(st_select_lex *values);
  void set_thd(THD *thd_arg) { thd= thd_arg; }
  inline bool is_union (); 

  friend void lex_start(THD *thd);
  friend int subselect_union_engine::exec();

  List<Item> *get_unit_column_types();
};

typedef class st_select_lex_unit SELECT_LEX_UNIT;

/*
  SELECT_LEX - store information of parsed SELECT statment
*/
class st_select_lex: public st_select_lex_node
{
public:
  Name_resolution_context context;
  char *db;
  Item *where, *having;                         /* WHERE & HAVING clauses */
  Item *prep_where; /* saved WHERE clause for prepared statement processing */
  Item *prep_having;/* saved HAVING clause for prepared statement processing */
  /* Saved values of the WHERE and HAVING clauses*/
  Item::cond_result cond_value, having_value;
  /* point on lex in which it was created, used in view subquery detection */
  st_lex *parent_lex;
  enum olap_type olap;
  /* FROM clause - points to the beginning of the TABLE_LIST::next_local list. */
  SQL_LIST	      table_list;
  SQL_LIST	      group_list; /* GROUP BY clause. */
  List<Item>          item_list;  /* list of fields & expressions */
  List<String>        interval_list;
  bool	              is_item_list_lookup;
  /* 
    Despite their names, the following are used in unions. This should 
    be rewritten. -Brian
  */
  List<Item_real_func> *ftfunc_list;
  List<Item_real_func> ftfunc_list_alloc;
  JOIN *join; /* after JOIN::prepare it is pointer to corresponding JOIN */
  List<TABLE_LIST> top_join_list; /* join list of the top level          */
  List<TABLE_LIST> *join_list;    /* list for the currently parsed join  */
  TABLE_LIST *embedding;          /* table embedding to the above list   */
  List<TABLE_LIST> sj_nests;
  /*
    Beginning of the list of leaves in a FROM clause, where the leaves
    inlcude all base tables including view tables. The tables are connected
    by TABLE_LIST::next_leaf, so leaf_tables points to the left-most leaf.
  */
  TABLE_LIST *leaf_tables;
  const char *type;               /* type of select for EXPLAIN          */

  SQL_LIST order_list;                /* ORDER clause */
  SQL_LIST *gorder_list;
  Item *select_limit, *offset_limit;  /* LIMIT clause parameters */
  // Arrays of pointers to top elements of all_fields list
  Item **ref_pointer_array;

  /*
    number of items in select_list and HAVING clause used to get number
    bigger then can be number of entries that will be added to all item
    list during split_sum_func
  */
  uint select_n_having_items;
  uint cond_count;    /* number of arguments of and/or/xor in where/having/on */
  uint between_count; /* number of between predicates in where/having/on      */
  uint max_equal_elems; /* maximal number of elements in multiple equalities  */   
  /*
    Number of fields used in select list or where clause of current select
    and all inner subselects.
  */
  uint select_n_where_fields;
  enum_parsing_place parsing_place; /* where we are parsing expression */
  bool with_sum_func;   /* sum function indicator */
  /* 
    PS or SP cond natural joins was alredy processed with permanent
    arena and all additional items which we need alredy stored in it
  */
  bool conds_processed_with_permanent_arena;

  ulong table_join_options;
  uint in_sum_expr;
  uint select_number; /* number of select (used for EXPLAIN) */
  int nest_level;     /* nesting level of select */
  Item_sum *inner_sum_func_list; /* list of sum func in nested selects */ 
  uint with_wild; /* item list contain '*' */
  bool  braces;   	/* SELECT ... UNION (SELECT ... ) <- this braces */
  /* TRUE when having fix field called in processing of this SELECT */
  bool having_fix_field;
  /* List of references to fields referenced from inner selects */
  List<Item_outer_ref> inner_refs_list;
  /* Number of Item_sum-derived objects in this SELECT */
  uint n_sum_items;
  /* Number of Item_sum-derived objects in children and descendant SELECTs */
  uint n_child_sum_items;

  /* explicit LIMIT clause was used */
  bool explicit_limit;
  /*
    there are subquery in HAVING clause => we can't close tables before
    query processing end even if we use temporary table
  */
  bool subquery_in_having;
  /* TRUE <=> this SELECT is correlated w.r.t. some ancestor select */
  bool is_correlated;
  /*
    This variable is required to ensure proper work of subqueries and
    stored procedures. Generally, one should use the states of
    Query_arena to determine if it's a statement prepare or first
    execution of a stored procedure. However, in case when there was an
    error during the first execution of a stored procedure, the SP body
    is not expelled from the SP cache. Therefore, a deeply nested
    subquery might be left unoptimized. So we need this per-subquery
    variable to inidicate the optimization/execution state of every
    subquery. Prepared statements work OK in that regard, as in
    case of an error during prepare the PS is not created.
  */
  bool first_execution;
  bool first_cond_optimization;
  /* do not wrap view fields with Item_ref */
  bool no_wrap_view_item;
  /* exclude this select from check of unique_table() */
  bool exclude_from_table_unique_test;
  /* List of fields that aren't under an aggregate function */
  List<Item_field> non_agg_fields;
  /* index in the select list of the expression currently being fixed */
  int cur_pos_in_select_list;

  List<udf_func>     udf_list;                  /* udf function calls stack */
  /* 
    This is a copy of the original JOIN USING list that comes from
    the parser. The parser :
      1. Sets the natural_join of the second TABLE_LIST in the join
         and the st_select_lex::prev_join_using.
      2. Makes a parent TABLE_LIST and sets its is_natural_join/
       join_using_fields members.
      3. Uses the wrapper TABLE_LIST as a table in the upper level.
    We cannot assign directly to join_using_fields in the parser because
    at stage (1.) the parent TABLE_LIST is not constructed yet and
    the assignment will override the JOIN USING fields of the lower level
    joins on the right.
  */
  List<String> *prev_join_using;
  /*
    Bitmap used in the ONLY_FULL_GROUP_BY_MODE to prevent mixture of aggregate
    functions and non aggregated fields when GROUP BY list is absent.
    Bits:
      0 - non aggregated fields are used in this select,
          defined as NON_AGG_FIELD_USED.
      1 - aggregate functions are used in this select,
          defined as SUM_FUNC_USED.
  */
  uint8 full_group_by_flag;
  void init_query();
  void init_select();
  st_select_lex_unit* master_unit();
  st_select_lex_unit* first_inner_unit() 
  { 
    return (st_select_lex_unit*) slave; 
  }
  st_select_lex* outer_select();
  st_select_lex* next_select() { return (st_select_lex*) next; }
  st_select_lex* next_select_in_list() 
  {
    return (st_select_lex*) link_next;
  }
  st_select_lex_node** next_select_in_list_addr()
  {
    return &link_next;
  }
  st_select_lex* return_after_parsing()
  {
    return master_unit()->return_after_parsing();
  }

  void mark_as_dependent(st_select_lex *last);

  bool set_braces(bool value);
  bool inc_in_sum_expr();
  uint get_in_sum_expr();

  bool add_item_to_list(THD *thd, Item *item);
  bool add_group_to_list(THD *thd, Item *item, bool asc);
  bool add_order_to_list(THD *thd, Item *item, bool asc);
  TABLE_LIST* add_table_to_list(THD *thd, Table_ident *table,
				LEX_STRING *alias,
				ulong table_options,
				thr_lock_type flags= TL_UNLOCK,
				List<Index_hint> *hints= 0,
                                LEX_STRING *option= 0);
  TABLE_LIST* get_table_list();
  bool init_nested_join(THD *thd);
  TABLE_LIST *end_nested_join(THD *thd);
  TABLE_LIST *nest_last_join(THD *thd);
  void add_joined_table(TABLE_LIST *table);
  TABLE_LIST *convert_right_join();
  List<Item>* get_item_list();
  ulong get_table_join_options();
  void set_lock_for_tables(thr_lock_type lock_type);
  inline void init_order()
  {
    order_list.elements= 0;
    order_list.first= 0;
    order_list.next= (uchar**) &order_list.first;
  }
  /*
    This method created for reiniting LEX in mysql_admin_table() and can be
    used only if you are going remove all SELECT_LEX & units except belonger
    to LEX (LEX::unit & LEX::select, for other purposes there are
    SELECT_LEX_UNIT::exclude_level & SELECT_LEX_UNIT::exclude_tree
  */
  void cut_subtree() { slave= 0; }
  bool test_limit();

  friend void lex_start(THD *thd);
  st_select_lex() : n_sum_items(0), n_child_sum_items(0) {}
  void make_empty_select()
  {
    init_query();
    init_select();
  }
  bool setup_ref_array(THD *thd, uint order_group_num);
  void print(THD *thd, String *str, enum_query_type query_type);
  static void print_order(String *str,
                          ORDER *order,
                          enum_query_type query_type);
  void print_limit(THD *thd, String *str, enum_query_type query_type);
  void fix_prepare_information(THD *thd, Item **conds, Item **having_conds);
  /*
    Destroy the used execution plan (JOIN) of this subtree (this
    SELECT_LEX and all nested SELECT_LEXes and SELECT_LEX_UNITs).
  */
  bool cleanup();
  /*
    Recursively cleanup the join of this select lex and of all nested
    select lexes.
  */
  void cleanup_all_joins(bool full);

  void set_index_hint_type(enum index_hint_type type, index_clause_map clause);

  /* 
   Add a index hint to the tagged list of hints. The type and clause of the
   hint will be the current ones (set by set_index_hint()) 
  */
  bool add_index_hint (THD *thd, char *str, uint length);

  /* make a list to hold index hints */
  void alloc_index_hints (THD *thd);
  /* read and clear the index hints */
  List<Index_hint>* pop_index_hints(void) 
  {
    List<Index_hint> *hints= index_hints;
    index_hints= NULL;
    return hints;
  }

  void clear_index_hints(void) { index_hints= NULL; }

private:  
  /* current index hint kind. used in filling up index_hints */
  enum index_hint_type current_index_hint_type;
  index_clause_map current_index_hint_clause;
  /* a list of USE/FORCE/IGNORE INDEX */
  List<Index_hint> *index_hints;
};
typedef class st_select_lex SELECT_LEX;

inline bool st_select_lex_unit::is_union ()
{ 
  return first_select()->next_select() && 
    first_select()->next_select()->linkage == UNION_TYPE;
}

#define ALTER_ADD_COLUMN	(1L << 0)
#define ALTER_DROP_COLUMN	(1L << 1)
#define ALTER_CHANGE_COLUMN	(1L << 2)
#define ALTER_COLUMN_STORAGE	(1L << 3)
#define ALTER_COLUMN_FORMAT	(1L << 4)
#define ALTER_COLUMN_ORDER      (1L << 5)
#define ALTER_ADD_INDEX		(1L << 6)
#define ALTER_DROP_INDEX	(1L << 7)
#define ALTER_RENAME		(1L << 8)
#define ALTER_ORDER		(1L << 9)
#define ALTER_OPTIONS		(1L << 10)
#define ALTER_COLUMN_DEFAULT    (1L << 11)
#define ALTER_KEYS_ONOFF        (1L << 12)
#define ALTER_STORAGE	        (1L << 13)
#define ALTER_ROW_FORMAT        (1L << 14)
#define ALTER_CONVERT           (1L << 15)
#define ALTER_FORCE		(1L << 16)
#define ALTER_RECREATE          (1L << 17)
#define ALTER_TABLE_REORG        (1L << 24)
#define ALTER_FOREIGN_KEY         (1L << 31)

/**
  @brief Parsing data for CREATE or ALTER TABLE.

  This structure contains a list of columns or indexes to be created,
  altered or dropped.
*/

class Alter_info
{
public:
  List<Alter_drop>              drop_list;
  List<Alter_column>            alter_list;
  List<Key>                     key_list;
  List<Create_field>            create_list;
  uint                          flags;
  enum enum_enable_or_disable   keys_onoff;
  enum tablespace_op_type       tablespace_op;
  uint                          no_parts;
  enum ha_build_method          build_method;
  Create_field                 *datetime_field;
  bool                          error_if_not_empty;


  Alter_info() :
    flags(0),
    keys_onoff(LEAVE_AS_IS),
    tablespace_op(NO_TABLESPACE_OP),
    no_parts(0),
    build_method(HA_BUILD_DEFAULT),
    datetime_field(NULL),
    error_if_not_empty(FALSE)
  {}

  void reset()
  {
    drop_list.empty();
    alter_list.empty();
    key_list.empty();
    create_list.empty();
    flags= 0;
    keys_onoff= LEAVE_AS_IS;
    tablespace_op= NO_TABLESPACE_OP;
    no_parts= 0;
    build_method= HA_BUILD_DEFAULT;
    datetime_field= 0;
    error_if_not_empty= FALSE;
  }
  Alter_info(const Alter_info &rhs, MEM_ROOT *mem_root);
private:
  Alter_info &operator=(const Alter_info &rhs); // not implemented
  Alter_info(const Alter_info &rhs);            // not implemented
};

enum xa_option_words {XA_NONE, XA_JOIN, XA_RESUME, XA_ONE_PHASE,
                      XA_SUSPEND, XA_FOR_MIGRATE};

extern const LEX_STRING null_lex_str;


/*
  Class representing list of all tables used by statement.
  It also contains information about stored functions used by statement
  since during its execution we may have to add all tables used by its
  stored functions/triggers to this list in order to pre-open and lock
  them.

  Also used by st_lex::reset_n_backup/restore_backup_query_tables_list()
  methods to save and restore this information.
*/

class Query_tables_list
{
public:
  /* Global list of all tables used by this statement */
  TABLE_LIST *query_tables;
  /* Pointer to next_global member of last element in the previous list. */
  TABLE_LIST **query_tables_last;
  /*
    If non-0 then indicates that query requires prelocking and points to
    next_global member of last own element in query table list (i.e. last
    table which was not added to it as part of preparation to prelocking).
    0 - indicates that this query does not need prelocking.
  */
  TABLE_LIST **query_tables_own_last;
  /*
    Set of stored routines called by statement.
    (Note that we use lazy-initialization for this hash).
  */
  enum { START_SROUTINES_HASH_SIZE= 16 };
  HASH sroutines;
  /*
    List linking elements of 'sroutines' set. Allows you to add new elements
    to this set as you iterate through the list of existing elements.
    'sroutines_list_own_last' is pointer to ::next member of last element of
    this list which represents routine which is explicitly used by query.
    'sroutines_list_own_elements' number of explicitly used routines.
    We use these two members for restoring of 'sroutines_list' to the state
    in which it was right after query parsing.
  */
  SQL_LIST sroutines_list;
  uchar    **sroutines_list_own_last;
  uint     sroutines_list_own_elements;

  /*
    These constructor and destructor serve for creation/destruction
    of Query_tables_list instances which are used as backup storage.
  */
  Query_tables_list() {}
  ~Query_tables_list() {}

  /* Initializes (or resets) Query_tables_list object for "real" use. */
  void reset_query_tables_list(bool init);
  void destroy_query_tables_list();
  void set_query_tables_list(Query_tables_list *state)
  {
    *this= *state;
  }

  /*
    Direct addition to the list of query tables.
    If you are using this function, you must ensure that the table
    object, in particular table->db member, is initialized.
  */
  void add_to_query_tables(TABLE_LIST *table)
  {
    *(table->prev_global= query_tables_last)= table;
    query_tables_last= &table->next_global;
  }
  /* Return pointer to first not-own table in query-tables or 0 */
  TABLE_LIST* first_not_own_table()
  {
    return ( query_tables_own_last ? *query_tables_own_last : 0);
  }
  void chop_off_not_own_tables()
  {
    if (query_tables_own_last)
    {
      *query_tables_own_last= 0;
      query_tables_last= query_tables_own_last;
      query_tables_own_last= 0;
    }
  }

  /**
     Has the parser/scanner detected that this statement is unsafe?
   */
  inline bool is_stmt_unsafe() const {
    return binlog_stmt_flags & (1U << BINLOG_STMT_FLAG_UNSAFE);
  }

  /**
     Flag the current (top-level) statement as unsafe.

     The flag will be reset after the statement has finished.

   */
  inline void set_stmt_unsafe() {
    binlog_stmt_flags|= (1U << BINLOG_STMT_FLAG_UNSAFE);
  }

  inline void clear_stmt_unsafe() {
    binlog_stmt_flags&= ~(1U << BINLOG_STMT_FLAG_UNSAFE);
  }

  /**
    true if the parsed tree contains references to stored procedures
    or functions, false otherwise
  */
  bool uses_stored_routines() const
  { return sroutines_list.elements != 0; }

private:
  enum enum_binlog_stmt_flag {
    BINLOG_STMT_FLAG_UNSAFE,
    BINLOG_STMT_FLAG_COUNT
  };

  /*
    Tells if the parsing stage detected properties of the statement,
    for example: that some items require row-based binlogging to give
    a reliable binlog/replication, or if we will use stored functions
    or triggers which themselves need require row-based binlogging.
  */
  uint32 binlog_stmt_flags;
};


/*
  st_parsing_options contains the flags for constructions that are
  allowed in the current statement.
*/

struct st_parsing_options
{
  bool allows_variable;
  bool allows_select_into;
  bool allows_select_procedure;
  bool allows_derived;

  st_parsing_options() { reset(); }
  void reset();
};


/**
  The state of the lexical parser, when parsing comments.
*/
enum enum_comment_state
{
  /**
    Not parsing comments.
  */
  NO_COMMENT,
  /**
    Parsing comments that need to be preserved.
    Typically, these are user comments '/' '*' ... '*' '/'.
  */
  PRESERVE_COMMENT,
  /**
    Parsing comments that need to be discarded.
    Typically, these are special comments '/' '*' '!' ... '*' '/',
    or '/' '*' '!' 'M' 'M' 'm' 'm' 'm' ... '*' '/', where the comment
    markers should not be expanded.
  */
  DISCARD_COMMENT
};


/**
  @brief This class represents the character input stream consumed during
  lexical analysis.

  In addition to consuming the input stream, this class performs some
  comment pre processing, by filtering out out of bound special text
  from the query input stream.
  Two buffers, with pointers inside each buffers, are maintained in
  parallel. The 'raw' buffer is the original query text, which may
  contain out-of-bound comments. The 'cpp' (for comments pre processor)
  is the pre-processed buffer that contains only the query text that
  should be seen once out-of-bound data is removed.
*/

class Lex_input_stream
{
public:
  Lex_input_stream(THD *thd, const char* buff, unsigned int length);
  ~Lex_input_stream();

  /**
    Set the echo mode.

    When echo is true, characters parsed from the raw input stream are
    preserved. When false, characters parsed are silently ignored.
    @param echo the echo mode.
  */
  void set_echo(bool echo)
  {
    m_echo= echo;
  }

  /**
    Skip binary from the input stream.
    @param n number of bytes to accept.
  */
  void skip_binary(int n)
  {
    if (m_echo)
    {
      memcpy(m_cpp_ptr, m_ptr, n);
      m_cpp_ptr += n;
    }
    m_ptr += n;
  }

  /**
    Get a character, and advance in the stream.
    @return the next character to parse.
  */
  char yyGet()
  {
    char c= *m_ptr++;
    if (m_echo)
      *m_cpp_ptr++ = c;
    return c;
  }

  /**
    Get the last character accepted.
    @return the last character accepted.
  */
  char yyGetLast()
  {
    return m_ptr[-1];
  }

  /**
    Look at the next character to parse, but do not accept it.
  */
  char yyPeek()
  {
    return m_ptr[0];
  }

  /**
    Look ahead at some character to parse.
    @param n offset of the character to look up
  */
  char yyPeekn(int n)
  {
    return m_ptr[n];
  }

  /**
    Cancel the effect of the last yyGet() or yySkip().
    Note that the echo mode should not change between calls to yyGet / yySkip
    and yyUnget. The caller is responsible for ensuring that.
  */
  void yyUnget()
  {
    m_ptr--;
    if (m_echo)
      m_cpp_ptr--;
  }

  /**
    Accept a character, by advancing the input stream.
  */
  void yySkip()
  {
    if (m_echo)
      *m_cpp_ptr++ = *m_ptr++;
    else
      m_ptr++;
  }

  /**
    Accept multiple characters at once.
    @param n the number of characters to accept.
  */
  void yySkipn(int n)
  {
    if (m_echo)
    {
      memcpy(m_cpp_ptr, m_ptr, n);
      m_cpp_ptr += n;
    }
    m_ptr += n;
  }

  /**
    End of file indicator for the query text to parse.
    @return true if there are no more characters to parse
  */
  bool eof()
  {
    return (m_ptr >= m_end_of_query);
  }

  /**
    End of file indicator for the query text to parse.
    @param n number of characters expected
    @return true if there are less than n characters to parse
  */
  bool eof(int n)
  {
    return ((m_ptr + n) >= m_end_of_query);
  }

  /** Get the raw query buffer. */
  const char *get_buf()
  {
    return m_buf;
  }

  /** Get the pre-processed query buffer. */
  const char *get_cpp_buf()
  {
    return m_cpp_buf;
  }

  /** Get the end of the raw query buffer. */
  const char *get_end_of_query()
  {
    return m_end_of_query;
  }

  /** Mark the stream position as the start of a new token. */
  void start_token()
  {
    m_tok_start_prev= m_tok_start;
    m_tok_start= m_ptr;
    m_tok_end= m_ptr;

    m_cpp_tok_start_prev= m_cpp_tok_start;
    m_cpp_tok_start= m_cpp_ptr;
    m_cpp_tok_end= m_cpp_ptr;
  }

  /**
    Adjust the starting position of the current token.
    This is used to compensate for starting whitespace.
  */
  void restart_token()
  {
    m_tok_start= m_ptr;
    m_cpp_tok_start= m_cpp_ptr;
  }

  /** Get the token start position, in the raw buffer. */
  const char *get_tok_start()
  {
    return m_tok_start;
  }

  /** Get the token start position, in the pre-processed buffer. */
  const char *get_cpp_tok_start()
  {
    return m_cpp_tok_start;
  }

  /** Get the token end position, in the raw buffer. */
  const char *get_tok_end()
  {
    return m_tok_end;
  }

  /** Get the token end position, in the pre-processed buffer. */
  const char *get_cpp_tok_end()
  {
    return m_cpp_tok_end;
  }

  /** Get the previous token start position, in the raw buffer. */
  const char *get_tok_start_prev()
  {
    return m_tok_start_prev;
  }

  /** Get the current stream pointer, in the raw buffer. */
  const char *get_ptr()
  {
    return m_ptr;
  }

  /** Get the current stream pointer, in the pre-processed buffer. */
  const char *get_cpp_ptr()
  {
    return m_cpp_ptr;
  }

  /** Get the length of the current token, in the raw buffer. */
  uint yyLength()
  {
    /*
      The assumption is that the lexical analyser is always 1 character ahead,
      which the -1 account for.
    */
    DBUG_ASSERT(m_ptr > m_tok_start);
    return (uint) ((m_ptr - m_tok_start) - 1);
  }

  /** Get the utf8-body string. */
  const char *get_body_utf8_str()
  {
    return m_body_utf8;
  }

  /** Get the utf8-body length. */
  uint get_body_utf8_length()
  {
    return m_body_utf8_ptr - m_body_utf8;
  }

  void body_utf8_start(THD *thd, const char *begin_ptr);
  void body_utf8_append(const char *ptr);
  void body_utf8_append(const char *ptr, const char *end_ptr);
  void body_utf8_append_literal(THD *thd,
                                const LEX_STRING *txt,
                                CHARSET_INFO *txt_cs,
                                const char *end_ptr);

  /** Current thread. */
  THD *m_thd;

  /** Current line number. */
  uint yylineno;

  /** Length of the last token parsed. */
  uint yytoklen;

  /** Interface with bison, value of the last token parsed. */
  LEX_YYSTYPE yylval;

  /** LALR(2) resolution, look ahead token.*/
  int lookahead_token;

  /** LALR(2) resolution, value of the look ahead token.*/
  LEX_YYSTYPE lookahead_yylval;

private:
  /** Pointer to the current position in the raw input stream. */
  const char *m_ptr;

  /** Starting position of the last token parsed, in the raw buffer. */
  const char *m_tok_start;

  /** Ending position of the previous token parsed, in the raw buffer. */
  const char *m_tok_end;

  /** End of the query text in the input stream, in the raw buffer. */
  const char *m_end_of_query;

  /** Starting position of the previous token parsed, in the raw buffer. */
  const char *m_tok_start_prev;

  /** Begining of the query text in the input stream, in the raw buffer. */
  const char *m_buf;

  /** Length of the raw buffer. */
  uint m_buf_length;

  /** Echo the parsed stream to the pre-processed buffer. */
  bool m_echo;

  /** Pre-processed buffer. */
  char *m_cpp_buf;

  /** Pointer to the current position in the pre-processed input stream. */
  char *m_cpp_ptr;

  /**
    Starting position of the last token parsed,
    in the pre-processed buffer.
  */
  const char *m_cpp_tok_start;

  /**
    Starting position of the previous token parsed,
    in the pre-procedded buffer.
  */
  const char *m_cpp_tok_start_prev;

  /**
    Ending position of the previous token parsed,
    in the pre-processed buffer.
  */
  const char *m_cpp_tok_end;

  /** UTF8-body buffer created during parsing. */
  char *m_body_utf8;

  /** Pointer to the current position in the UTF8-body buffer. */
  char *m_body_utf8_ptr;

  /**
    Position in the pre-processed buffer. The query from m_cpp_buf to
    m_cpp_utf_processed_ptr is converted to UTF8-body.
  */
  const char *m_cpp_utf8_processed_ptr;

public:

  /** Current state of the lexical analyser. */
  enum my_lex_states next_state;

  /**
    Position of ';' in the stream, to delimit multiple queries.
    This delimiter is in the raw buffer.
  */
  const char *found_semicolon;

  /** Token character bitmaps, to detect 7bit strings. */
  uchar tok_bitmap;

  /** SQL_MODE = IGNORE_SPACE. */
  bool ignore_space;

  /**
    TRUE if we're parsing a prepared statement: in this mode
    we should allow placeholders and disallow multi-statements.
  */
  bool stmt_prepare_mode;

  /** State of the lexical analyser for comments. */
  enum_comment_state in_comment;

  /**
    Starting position of the TEXT_STRING or IDENT in the pre-processed
    buffer.

    NOTE: this member must be used within MYSQLlex() function only.
  */
  const char *m_cpp_text_start;

  /**
    Ending position of the TEXT_STRING or IDENT in the pre-processed
    buffer.

    NOTE: this member must be used within MYSQLlex() function only.
    */
  const char *m_cpp_text_end;

  /**
    Character set specified by the character-set-introducer.

    NOTE: this member must be used within MYSQLlex() function only.
  */
  CHARSET_INFO *m_underscore_cs;
};


/* The state of the lex parsing. This is saved in the THD struct */

typedef struct st_lex : public Query_tables_list
{
  SELECT_LEX_UNIT unit;                         /* most upper unit */
  SELECT_LEX select_lex;                        /* first SELECT_LEX */
  /* current SELECT_LEX in parsing */
  SELECT_LEX *current_select;
  /* list of all SELECT_LEX */
  SELECT_LEX *all_selects_list;

  char *length,*dec,*change;
  LEX_STRING name;
  char *help_arg;
  LEX_STRING backup_dir;				/* For RESTORE/BACKUP */
  char* to_log;                                 /* For PURGE MASTER LOGS TO */
  char* x509_subject,*x509_issuer,*ssl_cipher;
  String *wild;
  sql_exchange *exchange;
  select_result *result;
  Item *default_value, *on_update_value;
  LEX_STRING comment, ident;
  XID *xid;
  uchar* yacc_yyss, *yacc_yyvs;
  THD *thd;

  /* maintain a list of used plugins for this LEX */
  DYNAMIC_ARRAY plugins;
  plugin_ref plugins_static_buffer[INITIAL_LEX_PLUGIN_LIST_SIZE];

  CHARSET_INFO *charset;
  bool text_string_is_7bit;
  /* store original leaf_tables for INSERT SELECT and PS/SP */
  TABLE_LIST *leaf_tables_insert;

  List<Key_part_spec> col_list;
  List<Key_part_spec> ref_list;
  List<String>	      interval_list;
  List<LEX_USER>      users_list;
  List<LEX_COLUMN>    columns;
  List<Item>	      *insert_list,field_list,value_list,update_list;
  List<List_item>     many_values;
  List<set_var_base>  var_list;
  List<Item_param>    param_list;
  List<LEX_STRING>    view_list; // view list (list of field names in view)
  /*
    A stack of name resolution contexts for the query. This stack is used
    at parse time to set local name resolution contexts for various parts
    of a query. For example, in a JOIN ... ON (some_condition) clause the
    Items in 'some_condition' must be resolved only against the operands
    of the the join, and not against the whole clause. Similarly, Items in
    subqueries should be resolved against the subqueries (and outer queries).
    The stack is used in the following way: when the parser detects that
    all Items in some clause need a local context, it creates a new context
    and pushes it on the stack. All newly created Items always store the
    top-most context in the stack. Once the parser leaves the clause that
    required a local context, the parser pops the top-most context.
  */
  List<Name_resolution_context> context_stack;
  List<LEX_STRING>     db_list;

  SQL_LIST	      proc_list, auxiliary_table_list, save_list;
  Create_field	      *last_field;
  Item_sum *in_sum_func;
  udf_func udf;
  HA_CHECK_OPT   check_opt;			// check/repair options
  HA_CREATE_INFO create_info;
  KEY_CREATE_INFO key_create_info;
  LEX_MASTER_INFO mi;				// used by CHANGE MASTER
  LEX_SERVER_OPTIONS server_options;
  USER_RESOURCES mqh;
  ulong type;
  /*
    This variable is used in post-parse stage to declare that sum-functions,
    or functions which have sense only if GROUP BY is present, are allowed.
    For example in a query
    SELECT ... FROM ...WHERE MIN(i) == 1 GROUP BY ... HAVING MIN(i) > 2
    MIN(i) in the WHERE clause is not allowed in the opposite to MIN(i)
    in the HAVING clause. Due to possible nesting of select construct
    the variable can contain 0 or 1 for each nest level.
  */
  nesting_map allow_sum_func;
  enum_sql_command sql_command;
  /*
    Usually `expr` rule of yacc is quite reused but some commands better
    not support subqueries which comes standard with this rule, like
    KILL, HA_READ, CREATE/ALTER EVENT etc. Set this to `false` to get
    syntax error back.
  */
  bool expr_allows_subselect;

  thr_lock_type lock_option;
  enum enum_duplicates duplicates;
  enum enum_tx_isolation tx_isolation;
  enum enum_ha_read_modes ha_read_mode;
  union {
    enum ha_rkey_function ha_rkey_mode;
    enum xa_option_words xa_opt;
    bool lock_transactional;            /* For LOCK TABLE ... IN ... MODE */
  };
  enum enum_var_type option_type;
  enum enum_drop_mode drop_mode;

  uint profile_query_id;
  uint profile_options;
  enum ha_storage_media storage_type;
  enum column_format_type column_format;
  uint which_columns;
  enum Foreign_key::fk_match_opt fk_match_option;
  enum Foreign_key::fk_option fk_update_opt;
  enum Foreign_key::fk_option fk_delete_opt;
  uint slave_thd_opt, start_transaction_opt;
  int nest_level;
  /*
    In LEX representing update which were transformed to multi-update
    stores total number of tables. For LEX representing multi-delete
    holds number of tables from which we will delete records.
  */
  uint table_count;
  uint8 describe;
  /*
    A flag that indicates what kinds of derived tables are present in the
    query (0 if no derived tables, otherwise DERIVED_SUBQUERY).
  */
  uint8 derived_tables;
  bool drop_if_exists, drop_temporary, local_file, one_shot_set;
  bool autocommit;
  bool verbose, no_write_to_binlog;

  bool tx_chain, tx_release;
  /*
    Special JOIN::prepare mode: changing of query is prohibited.
    When creating a view, we need to just check its syntax omitting
    any optimizations: afterwards definition of the view will be
    reconstructed by means of ::print() methods and written to
    to an .frm file. We need this definition to stay untouched.
  */
  bool view_prepare_mode;
  bool subqueries, ignore;
  st_parsing_options parsing_options;
  Alter_info alter_info;

  /*
    field_list was created for view and should be removed before PS/SP
    rexecuton
  */
  bool empty_field_list_on_rset;

  /*
    Pointers to part of LOAD DATA statement that should be rewritten
    during replication ("LOCAL 'filename' REPLACE INTO" part).
  */
  const char *fname_start;
  const char *fname_end;
  
  /**
    During name resolution search only in the table list given by 
    Name_resolution_context::first_name_resolution_table and
    Name_resolution_context::last_name_resolution_table
    (see Item_field::fix_fields()). 
  */
  bool use_only_table_context;

  /*
    Reference to a struct that contains information in various commands
    to add/create/drop/change table spaces.
  */
  st_alter_tablespace *alter_tablespace_info;
  
  bool escape_used;
  bool is_lex_started; /* If lex_start() did run. For debugging. */

  st_lex();

  virtual ~st_lex()
  {
    destroy_query_tables_list();
    plugin_unlock_list(NULL, (plugin_ref *)plugins.buffer, plugins.elements);
    delete_dynamic(&plugins);
  }

  TABLE_LIST *unlink_first_table(bool *link_to_local);
  void link_first_table_back(TABLE_LIST *first, bool link_to_local);
  void first_lists_tables_same();

  bool can_be_merged();
  bool can_use_merged();
  bool can_not_use_merged();
  bool only_view_structure();
  bool need_correct_ident();
  uint8 get_effective_with_check(TABLE_LIST *view);
  /*
    Is this update command where 'WHITH CHECK OPTION' clause is important

    SYNOPSIS
      st_lex::which_check_option_applicable()

    RETURN
      TRUE   have to take 'WHITH CHECK OPTION' clause into account
      FALSE  'WHITH CHECK OPTION' clause do not need
  */
  inline bool which_check_option_applicable()
  {
    switch (sql_command) {
    case SQLCOM_UPDATE:
    case SQLCOM_UPDATE_MULTI:
    case SQLCOM_INSERT:
    case SQLCOM_INSERT_SELECT:
    case SQLCOM_REPLACE:
    case SQLCOM_REPLACE_SELECT:
    case SQLCOM_LOAD:
      return TRUE;
    default:
      return FALSE;
    }
  }

  void cleanup_after_one_table_open();

  bool push_context(Name_resolution_context *context)
  {
    return context_stack.push_front(context);
  }

  void pop_context()
  {
    context_stack.pop();
  }

  bool copy_db_to(char **p_db, size_t *p_db_length) const;

  Name_resolution_context *current_context()
  {
    return context_stack.head();
  }
  /*
    Restore the LEX and THD in case of a parse error.
  */
  static void cleanup_lex_after_parse_error(THD *thd);

  void reset_n_backup_query_tables_list(Query_tables_list *backup);
  void restore_backup_query_tables_list(Query_tables_list *backup);

  bool table_or_sp_used();

  /**
    @brief check if the statement is a single-level join
    @return result of the check
      @retval TRUE  The statement doesn't contain subqueries, unions and 
                    stored procedure calls.
      @retval FALSE There are subqueries, UNIONs or stored procedure calls.
  */
  bool is_single_level_stmt() 
  { 
    /* 
      This check exploits the fact that the last added to all_select_list is
      on its top. So select_lex (as the first added) will be at the tail 
      of the list.
    */ 
    if (&select_lex == all_selects_list && !sroutines.records)
    {
      DBUG_ASSERT(!all_selects_list->next_select_in_list());
      return TRUE;
    }
    return FALSE;
  }
} LEX;

struct st_lex_local: public st_lex
{
  static void *operator new(size_t size) throw()
  {
    return sql_alloc(size);
  }
  static void *operator new(size_t size, MEM_ROOT *mem_root) throw()
  {
    return (void*) alloc_root(mem_root, (uint) size);
  }
  static void operator delete(void *ptr,size_t size)
  { TRASH(ptr, size); }
  static void operator delete(void *ptr, MEM_ROOT *mem_root)
  { /* Never called */ }
};

extern void lex_init(void);
extern void lex_free(void);
extern void lex_start(THD *thd);
extern void lex_end(LEX *lex);
extern int MYSQLlex(void *arg, void *yythd);

extern void trim_whitespace(CHARSET_INFO *cs, LEX_STRING *str);

extern bool is_lex_native_function(const LEX_STRING *name);

/**
  @} (End of group Semantic_Analysis)
*/

#endif /* MYSQL_SERVER */