xref: /sqlite-3.40.0/src/sqliteInt.h (revision 999cc5d7)
1 /*
2 ** 2001 September 15
3 **
4 ** The author disclaims copyright to this source code.  In place of
5 ** a legal notice, here is a blessing:
6 **
7 **    May you do good and not evil.
8 **    May you find forgiveness for yourself and forgive others.
9 **    May you share freely, never taking more than you give.
10 **
11 *************************************************************************
12 ** Internal interface definitions for SQLite.
13 **
14 ** @(#) $Id: sqliteInt.h,v 1.606 2007/08/30 14:10:30 drh Exp $
15 */
16 #ifndef _SQLITEINT_H_
17 #define _SQLITEINT_H_
18 #include "sqliteLimit.h"
19 
20 #define _XOPEN_SOURCE 500  /* Needed to enable pthread recursive mutexes */
21 
22 #if defined(SQLITE_TCL) || defined(TCLSH)
23 # include <tcl.h>
24 #endif
25 
26 /*
27 ** Many people are failing to set -DNDEBUG=1 when compiling SQLite.
28 ** Setting NDEBUG makes the code smaller and run faster.  So the following
29 ** lines are added to automatically set NDEBUG unless the -DSQLITE_DEBUG=1
30 ** option is set.  Thus NDEBUG becomes an opt-in rather than an opt-out
31 ** feature.
32 */
33 #if !defined(NDEBUG) && !defined(SQLITE_DEBUG)
34 # define NDEBUG 1
35 #endif
36 
37 /*
38 ** The SQLITE_THREADSAFE macro must be defined as either 0 or 1.
39 ** Older versions of SQLite used an optional THREADSAFE macro.
40 ** We support that for legacy
41 */
42 #if !defined(SQLITE_THREADSAFE)
43 #if defined(THREADSAFE)
44 # define SQLITE_THREADSAFE THREADSAFE
45 #else
46 # define SQLITE_THREADSAFE 1
47 #endif
48 #endif
49 
50 /*
51 ** These #defines should enable >2GB file support on Posix if the
52 ** underlying operating system supports it.  If the OS lacks
53 ** large file support, or if the OS is windows, these should be no-ops.
54 **
55 ** Large file support can be disabled using the -DSQLITE_DISABLE_LFS switch
56 ** on the compiler command line.  This is necessary if you are compiling
57 ** on a recent machine (ex: RedHat 7.2) but you want your code to work
58 ** on an older machine (ex: RedHat 6.0).  If you compile on RedHat 7.2
59 ** without this option, LFS is enable.  But LFS does not exist in the kernel
60 ** in RedHat 6.0, so the code won't work.  Hence, for maximum binary
61 ** portability you should omit LFS.
62 **
63 ** Similar is true for MacOS.  LFS is only supported on MacOS 9 and later.
64 */
65 #ifndef SQLITE_DISABLE_LFS
66 # define _LARGE_FILE       1
67 # ifndef _FILE_OFFSET_BITS
68 #   define _FILE_OFFSET_BITS 64
69 # endif
70 # define _LARGEFILE_SOURCE 1
71 #endif
72 
73 #include "sqlite3.h"
74 #include "hash.h"
75 #include "parse.h"
76 #include <stdio.h>
77 #include <stdlib.h>
78 #include <string.h>
79 #include <assert.h>
80 #include <stddef.h>
81 
82 #define sqlite3_isnan(X)  ((X)!=(X))
83 
84 /*
85 ** If compiling for a processor that lacks floating point support,
86 ** substitute integer for floating-point
87 */
88 #ifdef SQLITE_OMIT_FLOATING_POINT
89 # define double sqlite_int64
90 # define LONGDOUBLE_TYPE sqlite_int64
91 # ifndef SQLITE_BIG_DBL
92 #   define SQLITE_BIG_DBL (0x7fffffffffffffff)
93 # endif
94 # define SQLITE_OMIT_DATETIME_FUNCS 1
95 # define SQLITE_OMIT_TRACE 1
96 # undef SQLITE_MIXED_ENDIAN_64BIT_FLOAT
97 #endif
98 #ifndef SQLITE_BIG_DBL
99 # define SQLITE_BIG_DBL (1e99)
100 #endif
101 
102 /*
103 ** OMIT_TEMPDB is set to 1 if SQLITE_OMIT_TEMPDB is defined, or 0
104 ** afterward. Having this macro allows us to cause the C compiler
105 ** to omit code used by TEMP tables without messy #ifndef statements.
106 */
107 #ifdef SQLITE_OMIT_TEMPDB
108 #define OMIT_TEMPDB 1
109 #else
110 #define OMIT_TEMPDB 0
111 #endif
112 
113 /*
114 ** If the following macro is set to 1, then NULL values are considered
115 ** distinct when determining whether or not two entries are the same
116 ** in a UNIQUE index.  This is the way PostgreSQL, Oracle, DB2, MySQL,
117 ** OCELOT, and Firebird all work.  The SQL92 spec explicitly says this
118 ** is the way things are suppose to work.
119 **
120 ** If the following macro is set to 0, the NULLs are indistinct for
121 ** a UNIQUE index.  In this mode, you can only have a single NULL entry
122 ** for a column declared UNIQUE.  This is the way Informix and SQL Server
123 ** work.
124 */
125 #define NULL_DISTINCT_FOR_UNIQUE 1
126 
127 /*
128 ** The "file format" number is an integer that is incremented whenever
129 ** the VDBE-level file format changes.  The following macros define the
130 ** the default file format for new databases and the maximum file format
131 ** that the library can read.
132 */
133 #define SQLITE_MAX_FILE_FORMAT 4
134 #ifndef SQLITE_DEFAULT_FILE_FORMAT
135 # define SQLITE_DEFAULT_FILE_FORMAT 1
136 #endif
137 
138 /*
139 ** Provide a default value for TEMP_STORE in case it is not specified
140 ** on the command-line
141 */
142 #ifndef TEMP_STORE
143 # define TEMP_STORE 1
144 #endif
145 
146 /*
147 ** GCC does not define the offsetof() macro so we'll have to do it
148 ** ourselves.
149 */
150 #ifndef offsetof
151 #define offsetof(STRUCTURE,FIELD) ((int)((char*)&((STRUCTURE*)0)->FIELD))
152 #endif
153 
154 /*
155 ** Check to see if this machine uses EBCDIC.  (Yes, believe it or
156 ** not, there are still machines out there that use EBCDIC.)
157 */
158 #if 'A' == '\301'
159 # define SQLITE_EBCDIC 1
160 #else
161 # define SQLITE_ASCII 1
162 #endif
163 
164 /*
165 ** Integers of known sizes.  These typedefs might change for architectures
166 ** where the sizes very.  Preprocessor macros are available so that the
167 ** types can be conveniently redefined at compile-type.  Like this:
168 **
169 **         cc '-DUINTPTR_TYPE=long long int' ...
170 */
171 #ifndef UINT32_TYPE
172 # define UINT32_TYPE unsigned int
173 #endif
174 #ifndef UINT16_TYPE
175 # define UINT16_TYPE unsigned short int
176 #endif
177 #ifndef INT16_TYPE
178 # define INT16_TYPE short int
179 #endif
180 #ifndef UINT8_TYPE
181 # define UINT8_TYPE unsigned char
182 #endif
183 #ifndef INT8_TYPE
184 # define INT8_TYPE signed char
185 #endif
186 #ifndef LONGDOUBLE_TYPE
187 # define LONGDOUBLE_TYPE long double
188 #endif
189 typedef sqlite_int64 i64;          /* 8-byte signed integer */
190 typedef sqlite_uint64 u64;         /* 8-byte unsigned integer */
191 typedef UINT32_TYPE u32;           /* 4-byte unsigned integer */
192 typedef UINT16_TYPE u16;           /* 2-byte unsigned integer */
193 typedef INT16_TYPE i16;            /* 2-byte signed integer */
194 typedef UINT8_TYPE u8;             /* 1-byte unsigned integer */
195 typedef UINT8_TYPE i8;             /* 1-byte signed integer */
196 
197 /*
198 ** Macros to determine whether the machine is big or little endian,
199 ** evaluated at runtime.
200 */
201 #ifdef SQLITE_AMALGAMATION
202 const int sqlite3One;
203 #else
204 extern const int sqlite3one;
205 #endif
206 #if defined(i386) || defined(__i386__) || defined(_M_IX86)
207 # define SQLITE_BIGENDIAN    0
208 # define SQLITE_LITTLEENDIAN 1
209 # define SQLITE_UTF16NATIVE  SQLITE_UTF16LE
210 #else
211 # define SQLITE_BIGENDIAN    (*(char *)(&sqlite3one)==0)
212 # define SQLITE_LITTLEENDIAN (*(char *)(&sqlite3one)==1)
213 # define SQLITE_UTF16NATIVE (SQLITE_BIGENDIAN?SQLITE_UTF16BE:SQLITE_UTF16LE)
214 #endif
215 
216 /*
217 ** An instance of the following structure is used to store the busy-handler
218 ** callback for a given sqlite handle.
219 **
220 ** The sqlite.busyHandler member of the sqlite struct contains the busy
221 ** callback for the database handle. Each pager opened via the sqlite
222 ** handle is passed a pointer to sqlite.busyHandler. The busy-handler
223 ** callback is currently invoked only from within pager.c.
224 */
225 typedef struct BusyHandler BusyHandler;
226 struct BusyHandler {
227   int (*xFunc)(void *,int);  /* The busy callback */
228   void *pArg;                /* First arg to busy callback */
229   int nBusy;                 /* Incremented with each busy call */
230 };
231 
232 /*
233 ** Defer sourcing vdbe.h and btree.h until after the "u8" and
234 ** "BusyHandler typedefs.
235 */
236 #include "btree.h"
237 #include "vdbe.h"
238 #include "pager.h"
239 
240 
241 /*
242 ** Name of the master database table.  The master database table
243 ** is a special table that holds the names and attributes of all
244 ** user tables and indices.
245 */
246 #define MASTER_NAME       "sqlite_master"
247 #define TEMP_MASTER_NAME  "sqlite_temp_master"
248 
249 /*
250 ** The root-page of the master database table.
251 */
252 #define MASTER_ROOT       1
253 
254 /*
255 ** The name of the schema table.
256 */
257 #define SCHEMA_TABLE(x)  ((!OMIT_TEMPDB)&&(x==1)?TEMP_MASTER_NAME:MASTER_NAME)
258 
259 /*
260 ** A convenience macro that returns the number of elements in
261 ** an array.
262 */
263 #define ArraySize(X)    (sizeof(X)/sizeof(X[0]))
264 
265 /*
266 ** Forward references to structures
267 */
268 typedef struct AggInfo AggInfo;
269 typedef struct AuthContext AuthContext;
270 typedef struct CollSeq CollSeq;
271 typedef struct Column Column;
272 typedef struct Db Db;
273 typedef struct Schema Schema;
274 typedef struct Expr Expr;
275 typedef struct ExprList ExprList;
276 typedef struct FKey FKey;
277 typedef struct FuncDef FuncDef;
278 typedef struct IdList IdList;
279 typedef struct Index Index;
280 typedef struct KeyClass KeyClass;
281 typedef struct KeyInfo KeyInfo;
282 typedef struct Module Module;
283 typedef struct NameContext NameContext;
284 typedef struct Parse Parse;
285 typedef struct Select Select;
286 typedef struct SrcList SrcList;
287 typedef struct Table Table;
288 typedef struct TableLock TableLock;
289 typedef struct Token Token;
290 typedef struct TriggerStack TriggerStack;
291 typedef struct TriggerStep TriggerStep;
292 typedef struct Trigger Trigger;
293 typedef struct WhereInfo WhereInfo;
294 typedef struct WhereLevel WhereLevel;
295 
296 #include "os.h"
297 #include "mutex.h"
298 
299 /*
300 ** Each database file to be accessed by the system is an instance
301 ** of the following structure.  There are normally two of these structures
302 ** in the sqlite.aDb[] array.  aDb[0] is the main database file and
303 ** aDb[1] is the database file used to hold temporary tables.  Additional
304 ** databases may be attached.
305 */
306 struct Db {
307   char *zName;         /* Name of this database */
308   Btree *pBt;          /* The B*Tree structure for this database file */
309   u8 inTrans;          /* 0: not writable.  1: Transaction.  2: Checkpoint */
310   u8 safety_level;     /* How aggressive at synching data to disk */
311   void *pAux;               /* Auxiliary data.  Usually NULL */
312   void (*xFreeAux)(void*);  /* Routine to free pAux */
313   Schema *pSchema;     /* Pointer to database schema (possibly shared) */
314 };
315 
316 /*
317 ** An instance of the following structure stores a database schema.
318 **
319 ** If there are no virtual tables configured in this schema, the
320 ** Schema.db variable is set to NULL. After the first virtual table
321 ** has been added, it is set to point to the database connection
322 ** used to create the connection. Once a virtual table has been
323 ** added to the Schema structure and the Schema.db variable populated,
324 ** only that database connection may use the Schema to prepare
325 ** statements.
326 */
327 struct Schema {
328   int schema_cookie;   /* Database schema version number for this file */
329   Hash tblHash;        /* All tables indexed by name */
330   Hash idxHash;        /* All (named) indices indexed by name */
331   Hash trigHash;       /* All triggers indexed by name */
332   Hash aFKey;          /* Foreign keys indexed by to-table */
333   Table *pSeqTab;      /* The sqlite_sequence table used by AUTOINCREMENT */
334   u8 file_format;      /* Schema format version for this file */
335   u8 enc;              /* Text encoding used by this database */
336   u16 flags;           /* Flags associated with this schema */
337   int cache_size;      /* Number of pages to use in the cache */
338 #ifndef SQLITE_OMIT_VIRTUALTABLE
339   sqlite3 *db;         /* "Owner" connection. See comment above */
340 #endif
341 };
342 
343 /*
344 ** These macros can be used to test, set, or clear bits in the
345 ** Db.flags field.
346 */
347 #define DbHasProperty(D,I,P)     (((D)->aDb[I].pSchema->flags&(P))==(P))
348 #define DbHasAnyProperty(D,I,P)  (((D)->aDb[I].pSchema->flags&(P))!=0)
349 #define DbSetProperty(D,I,P)     (D)->aDb[I].pSchema->flags|=(P)
350 #define DbClearProperty(D,I,P)   (D)->aDb[I].pSchema->flags&=~(P)
351 
352 /*
353 ** Allowed values for the DB.flags field.
354 **
355 ** The DB_SchemaLoaded flag is set after the database schema has been
356 ** read into internal hash tables.
357 **
358 ** DB_UnresetViews means that one or more views have column names that
359 ** have been filled out.  If the schema changes, these column names might
360 ** changes and so the view will need to be reset.
361 */
362 #define DB_SchemaLoaded    0x0001  /* The schema has been loaded */
363 #define DB_UnresetViews    0x0002  /* Some views have defined column names */
364 #define DB_Empty           0x0004  /* The file is empty (length 0 bytes) */
365 
366 
367 /*
368 ** Each database is an instance of the following structure.
369 **
370 ** The sqlite.lastRowid records the last insert rowid generated by an
371 ** insert statement.  Inserts on views do not affect its value.  Each
372 ** trigger has its own context, so that lastRowid can be updated inside
373 ** triggers as usual.  The previous value will be restored once the trigger
374 ** exits.  Upon entering a before or instead of trigger, lastRowid is no
375 ** longer (since after version 2.8.12) reset to -1.
376 **
377 ** The sqlite.nChange does not count changes within triggers and keeps no
378 ** context.  It is reset at start of sqlite3_exec.
379 ** The sqlite.lsChange represents the number of changes made by the last
380 ** insert, update, or delete statement.  It remains constant throughout the
381 ** length of a statement and is then updated by OP_SetCounts.  It keeps a
382 ** context stack just like lastRowid so that the count of changes
383 ** within a trigger is not seen outside the trigger.  Changes to views do not
384 ** affect the value of lsChange.
385 ** The sqlite.csChange keeps track of the number of current changes (since
386 ** the last statement) and is used to update sqlite_lsChange.
387 **
388 ** The member variables sqlite.errCode, sqlite.zErrMsg and sqlite.zErrMsg16
389 ** store the most recent error code and, if applicable, string. The
390 ** internal function sqlite3Error() is used to set these variables
391 ** consistently.
392 */
393 struct sqlite3 {
394   sqlite3_vfs *pVfs;            /* OS Interface */
395   int nDb;                      /* Number of backends currently in use */
396   Db *aDb;                      /* All backends */
397   int flags;                    /* Miscellanous flags. See below */
398   int errCode;                  /* Most recent error code (SQLITE_*) */
399   int errMask;                  /* & result codes with this before returning */
400   u8 autoCommit;                /* The auto-commit flag. */
401   u8 temp_store;                /* 1: file 2: memory 0: default */
402   u8 mallocFailed;              /* True if we have seen a malloc failure */
403   int nTable;                   /* Number of tables in the database */
404   CollSeq *pDfltColl;           /* The default collating sequence (BINARY) */
405   i64 lastRowid;                /* ROWID of most recent insert (see above) */
406   i64 priorNewRowid;            /* Last randomly generated ROWID */
407   int magic;                    /* Magic number for detect library misuse */
408   int nChange;                  /* Value returned by sqlite3_changes() */
409   int nTotalChange;             /* Value returned by sqlite3_total_changes() */
410   sqlite3_mutex *mutex;         /* Connection mutex */
411   struct sqlite3InitInfo {      /* Information used during initialization */
412     int iDb;                    /* When back is being initialized */
413     int newTnum;                /* Rootpage of table being initialized */
414     u8 busy;                    /* TRUE if currently initializing */
415   } init;
416   int nExtension;               /* Number of loaded extensions */
417   void **aExtension;            /* Array of shared libraray handles */
418   struct Vdbe *pVdbe;           /* List of active virtual machines */
419   int activeVdbeCnt;            /* Number of vdbes currently executing */
420   void (*xTrace)(void*,const char*);        /* Trace function */
421   void *pTraceArg;                          /* Argument to the trace function */
422   void (*xProfile)(void*,const char*,u64);  /* Profiling function */
423   void *pProfileArg;                        /* Argument to profile function */
424   void *pCommitArg;                 /* Argument to xCommitCallback() */
425   int (*xCommitCallback)(void*);    /* Invoked at every commit. */
426   void *pRollbackArg;               /* Argument to xRollbackCallback() */
427   void (*xRollbackCallback)(void*); /* Invoked at every commit. */
428   void *pUpdateArg;
429   void (*xUpdateCallback)(void*,int, const char*,const char*,sqlite_int64);
430   void(*xCollNeeded)(void*,sqlite3*,int eTextRep,const char*);
431   void(*xCollNeeded16)(void*,sqlite3*,int eTextRep,const void*);
432   void *pCollNeededArg;
433   sqlite3_value *pErr;          /* Most recent error message */
434   char *zErrMsg;                /* Most recent error message (UTF-8 encoded) */
435   char *zErrMsg16;              /* Most recent error message (UTF-16 encoded) */
436   union {
437     int isInterrupted;          /* True if sqlite3_interrupt has been called */
438     double notUsed1;            /* Spacer */
439   } u1;
440 #ifndef SQLITE_OMIT_AUTHORIZATION
441   int (*xAuth)(void*,int,const char*,const char*,const char*,const char*);
442                                 /* Access authorization function */
443   void *pAuthArg;               /* 1st argument to the access auth function */
444 #endif
445 #ifndef SQLITE_OMIT_PROGRESS_CALLBACK
446   int (*xProgress)(void *);     /* The progress callback */
447   void *pProgressArg;           /* Argument to the progress callback */
448   int nProgressOps;             /* Number of opcodes for progress callback */
449 #endif
450 #ifndef SQLITE_OMIT_VIRTUALTABLE
451   Hash aModule;                 /* populated by sqlite3_create_module() */
452   Table *pVTab;                 /* vtab with active Connect/Create method */
453   sqlite3_vtab **aVTrans;       /* Virtual tables with open transactions */
454   int nVTrans;                  /* Allocated size of aVTrans */
455 #endif
456   Hash aFunc;                   /* All functions that can be in SQL exprs */
457   Hash aCollSeq;                /* All collating sequences */
458   BusyHandler busyHandler;      /* Busy callback */
459   int busyTimeout;              /* Busy handler timeout, in msec */
460   Db aDbStatic[2];              /* Static space for the 2 default backends */
461 #ifdef SQLITE_SSE
462   sqlite3_stmt *pFetch;         /* Used by SSE to fetch stored statements */
463 #endif
464   u8 dfltLockMode;              /* Default locking-mode for attached dbs */
465 };
466 
467 /*
468 ** A macro to discover the encoding of a database.
469 */
470 #define ENC(db) ((db)->aDb[0].pSchema->enc)
471 
472 /*
473 ** Possible values for the sqlite.flags and or Db.flags fields.
474 **
475 ** On sqlite.flags, the SQLITE_InTrans value means that we have
476 ** executed a BEGIN.  On Db.flags, SQLITE_InTrans means a statement
477 ** transaction is active on that particular database file.
478 */
479 #define SQLITE_VdbeTrace      0x00000001  /* True to trace VDBE execution */
480 #define SQLITE_InTrans        0x00000008  /* True if in a transaction */
481 #define SQLITE_InternChanges  0x00000010  /* Uncommitted Hash table changes */
482 #define SQLITE_FullColNames   0x00000020  /* Show full column names on SELECT */
483 #define SQLITE_ShortColNames  0x00000040  /* Show short columns names */
484 #define SQLITE_CountRows      0x00000080  /* Count rows changed by INSERT, */
485                                           /*   DELETE, or UPDATE and return */
486                                           /*   the count using a callback. */
487 #define SQLITE_NullCallback   0x00000100  /* Invoke the callback once if the */
488                                           /*   result set is empty */
489 #define SQLITE_SqlTrace       0x00000200  /* Debug print SQL as it executes */
490 #define SQLITE_VdbeListing    0x00000400  /* Debug listings of VDBE programs */
491 #define SQLITE_WriteSchema    0x00000800  /* OK to update SQLITE_MASTER */
492 #define SQLITE_NoReadlock     0x00001000  /* Readlocks are omitted when
493                                           ** accessing read-only databases */
494 #define SQLITE_IgnoreChecks   0x00002000  /* Do not enforce check constraints */
495 #define SQLITE_ReadUncommitted 0x00004000 /* For shared-cache mode */
496 #define SQLITE_LegacyFileFmt  0x00008000  /* Create new databases in format 1 */
497 #define SQLITE_FullFSync      0x00010000  /* Use full fsync on the backend */
498 #define SQLITE_LoadExtension  0x00020000  /* Enable load_extension */
499 
500 #define SQLITE_RecoveryMode   0x00040000  /* Ignore schema errors */
501 #define SQLITE_SharedCache    0x00080000  /* Cache sharing is enabled */
502 #define SQLITE_Vtab           0x00100000  /* There exists a virtual table */
503 
504 /*
505 ** Possible values for the sqlite.magic field.
506 ** The numbers are obtained at random and have no special meaning, other
507 ** than being distinct from one another.
508 */
509 #define SQLITE_MAGIC_OPEN     0xa029a697  /* Database is open */
510 #define SQLITE_MAGIC_CLOSED   0x9f3c2d33  /* Database is closed */
511 #define SQLITE_MAGIC_BUSY     0xf03b7906  /* Database currently in use */
512 #define SQLITE_MAGIC_ERROR    0xb5357930  /* An SQLITE_MISUSE error occurred */
513 
514 /*
515 ** Each SQL function is defined by an instance of the following
516 ** structure.  A pointer to this structure is stored in the sqlite.aFunc
517 ** hash table.  When multiple functions have the same name, the hash table
518 ** points to a linked list of these structures.
519 */
520 struct FuncDef {
521   i16 nArg;            /* Number of arguments.  -1 means unlimited */
522   u8 iPrefEnc;         /* Preferred text encoding (SQLITE_UTF8, 16LE, 16BE) */
523   u8 needCollSeq;      /* True if sqlite3GetFuncCollSeq() might be called */
524   u8 flags;            /* Some combination of SQLITE_FUNC_* */
525   void *pUserData;     /* User data parameter */
526   FuncDef *pNext;      /* Next function with same name */
527   void (*xFunc)(sqlite3_context*,int,sqlite3_value**); /* Regular function */
528   void (*xStep)(sqlite3_context*,int,sqlite3_value**); /* Aggregate step */
529   void (*xFinalize)(sqlite3_context*);                /* Aggregate finializer */
530   char zName[1];       /* SQL name of the function.  MUST BE LAST */
531 };
532 
533 /*
534 ** Each SQLite module (virtual table definition) is defined by an
535 ** instance of the following structure, stored in the sqlite3.aModule
536 ** hash table.
537 */
538 struct Module {
539   const sqlite3_module *pModule;       /* Callback pointers */
540   const char *zName;                   /* Name passed to create_module() */
541   void *pAux;                          /* pAux passed to create_module() */
542   void (*xDestroy)(void *);            /* Module destructor function */
543 };
544 
545 /*
546 ** Possible values for FuncDef.flags
547 */
548 #define SQLITE_FUNC_LIKE   0x01  /* Candidate for the LIKE optimization */
549 #define SQLITE_FUNC_CASE   0x02  /* Case-sensitive LIKE-type function */
550 #define SQLITE_FUNC_EPHEM  0x04  /* Ephermeral.  Delete with VDBE */
551 
552 /*
553 ** information about each column of an SQL table is held in an instance
554 ** of this structure.
555 */
556 struct Column {
557   char *zName;     /* Name of this column */
558   Expr *pDflt;     /* Default value of this column */
559   char *zType;     /* Data type for this column */
560   char *zColl;     /* Collating sequence.  If NULL, use the default */
561   u8 notNull;      /* True if there is a NOT NULL constraint */
562   u8 isPrimKey;    /* True if this column is part of the PRIMARY KEY */
563   char affinity;   /* One of the SQLITE_AFF_... values */
564 #ifndef SQLITE_OMIT_VIRTUALTABLE
565   u8 isHidden;     /* True if this column is 'hidden' */
566 #endif
567 };
568 
569 /*
570 ** A "Collating Sequence" is defined by an instance of the following
571 ** structure. Conceptually, a collating sequence consists of a name and
572 ** a comparison routine that defines the order of that sequence.
573 **
574 ** There may two seperate implementations of the collation function, one
575 ** that processes text in UTF-8 encoding (CollSeq.xCmp) and another that
576 ** processes text encoded in UTF-16 (CollSeq.xCmp16), using the machine
577 ** native byte order. When a collation sequence is invoked, SQLite selects
578 ** the version that will require the least expensive encoding
579 ** translations, if any.
580 **
581 ** The CollSeq.pUser member variable is an extra parameter that passed in
582 ** as the first argument to the UTF-8 comparison function, xCmp.
583 ** CollSeq.pUser16 is the equivalent for the UTF-16 comparison function,
584 ** xCmp16.
585 **
586 ** If both CollSeq.xCmp and CollSeq.xCmp16 are NULL, it means that the
587 ** collating sequence is undefined.  Indices built on an undefined
588 ** collating sequence may not be read or written.
589 */
590 struct CollSeq {
591   char *zName;          /* Name of the collating sequence, UTF-8 encoded */
592   u8 enc;               /* Text encoding handled by xCmp() */
593   u8 type;              /* One of the SQLITE_COLL_... values below */
594   void *pUser;          /* First argument to xCmp() */
595   int (*xCmp)(void*,int, const void*, int, const void*);
596   void (*xDel)(void*);  /* Destructor for pUser */
597 };
598 
599 /*
600 ** Allowed values of CollSeq flags:
601 */
602 #define SQLITE_COLL_BINARY  1  /* The default memcmp() collating sequence */
603 #define SQLITE_COLL_NOCASE  2  /* The built-in NOCASE collating sequence */
604 #define SQLITE_COLL_REVERSE 3  /* The built-in REVERSE collating sequence */
605 #define SQLITE_COLL_USER    0  /* Any other user-defined collating sequence */
606 
607 /*
608 ** A sort order can be either ASC or DESC.
609 */
610 #define SQLITE_SO_ASC       0  /* Sort in ascending order */
611 #define SQLITE_SO_DESC      1  /* Sort in ascending order */
612 
613 /*
614 ** Column affinity types.
615 **
616 ** These used to have mnemonic name like 'i' for SQLITE_AFF_INTEGER and
617 ** 't' for SQLITE_AFF_TEXT.  But we can save a little space and improve
618 ** the speed a little by number the values consecutively.
619 **
620 ** But rather than start with 0 or 1, we begin with 'a'.  That way,
621 ** when multiple affinity types are concatenated into a string and
622 ** used as the P3 operand, they will be more readable.
623 **
624 ** Note also that the numeric types are grouped together so that testing
625 ** for a numeric type is a single comparison.
626 */
627 #define SQLITE_AFF_TEXT     'a'
628 #define SQLITE_AFF_NONE     'b'
629 #define SQLITE_AFF_NUMERIC  'c'
630 #define SQLITE_AFF_INTEGER  'd'
631 #define SQLITE_AFF_REAL     'e'
632 
633 #define sqlite3IsNumericAffinity(X)  ((X)>=SQLITE_AFF_NUMERIC)
634 
635 /*
636 ** Each SQL table is represented in memory by an instance of the
637 ** following structure.
638 **
639 ** Table.zName is the name of the table.  The case of the original
640 ** CREATE TABLE statement is stored, but case is not significant for
641 ** comparisons.
642 **
643 ** Table.nCol is the number of columns in this table.  Table.aCol is a
644 ** pointer to an array of Column structures, one for each column.
645 **
646 ** If the table has an INTEGER PRIMARY KEY, then Table.iPKey is the index of
647 ** the column that is that key.   Otherwise Table.iPKey is negative.  Note
648 ** that the datatype of the PRIMARY KEY must be INTEGER for this field to
649 ** be set.  An INTEGER PRIMARY KEY is used as the rowid for each row of
650 ** the table.  If a table has no INTEGER PRIMARY KEY, then a random rowid
651 ** is generated for each row of the table.  Table.hasPrimKey is true if
652 ** the table has any PRIMARY KEY, INTEGER or otherwise.
653 **
654 ** Table.tnum is the page number for the root BTree page of the table in the
655 ** database file.  If Table.iDb is the index of the database table backend
656 ** in sqlite.aDb[].  0 is for the main database and 1 is for the file that
657 ** holds temporary tables and indices.  If Table.isEphem
658 ** is true, then the table is stored in a file that is automatically deleted
659 ** when the VDBE cursor to the table is closed.  In this case Table.tnum
660 ** refers VDBE cursor number that holds the table open, not to the root
661 ** page number.  Transient tables are used to hold the results of a
662 ** sub-query that appears instead of a real table name in the FROM clause
663 ** of a SELECT statement.
664 */
665 struct Table {
666   char *zName;     /* Name of the table */
667   int nCol;        /* Number of columns in this table */
668   Column *aCol;    /* Information about each column */
669   int iPKey;       /* If not less then 0, use aCol[iPKey] as the primary key */
670   Index *pIndex;   /* List of SQL indexes on this table. */
671   int tnum;        /* Root BTree node for this table (see note above) */
672   Select *pSelect; /* NULL for tables.  Points to definition if a view. */
673   int nRef;          /* Number of pointers to this Table */
674   Trigger *pTrigger; /* List of SQL triggers on this table */
675   FKey *pFKey;       /* Linked list of all foreign keys in this table */
676   char *zColAff;     /* String defining the affinity of each column */
677 #ifndef SQLITE_OMIT_CHECK
678   Expr *pCheck;      /* The AND of all CHECK constraints */
679 #endif
680 #ifndef SQLITE_OMIT_ALTERTABLE
681   int addColOffset;  /* Offset in CREATE TABLE statement to add a new column */
682 #endif
683   u8 readOnly;     /* True if this table should not be written by the user */
684   u8 isEphem;      /* True if created using OP_OpenEphermeral */
685   u8 hasPrimKey;   /* True if there exists a primary key */
686   u8 keyConf;      /* What to do in case of uniqueness conflict on iPKey */
687   u8 autoInc;      /* True if the integer primary key is autoincrement */
688 #ifndef SQLITE_OMIT_VIRTUALTABLE
689   u8 isVirtual;             /* True if this is a virtual table */
690   u8 isCommit;              /* True once the CREATE TABLE has been committed */
691   Module *pMod;             /* Pointer to the implementation of the module */
692   sqlite3_vtab *pVtab;      /* Pointer to the module instance */
693   int nModuleArg;           /* Number of arguments to the module */
694   char **azModuleArg;       /* Text of all module args. [0] is module name */
695 #endif
696   Schema *pSchema;
697 };
698 
699 /*
700 ** Test to see whether or not a table is a virtual table.  This is
701 ** done as a macro so that it will be optimized out when virtual
702 ** table support is omitted from the build.
703 */
704 #ifndef SQLITE_OMIT_VIRTUALTABLE
705 #  define IsVirtual(X)      ((X)->isVirtual)
706 #  define IsHiddenColumn(X) ((X)->isHidden)
707 #else
708 #  define IsVirtual(X)      0
709 #  define IsHiddenColumn(X) 0
710 #endif
711 
712 /*
713 ** Each foreign key constraint is an instance of the following structure.
714 **
715 ** A foreign key is associated with two tables.  The "from" table is
716 ** the table that contains the REFERENCES clause that creates the foreign
717 ** key.  The "to" table is the table that is named in the REFERENCES clause.
718 ** Consider this example:
719 **
720 **     CREATE TABLE ex1(
721 **       a INTEGER PRIMARY KEY,
722 **       b INTEGER CONSTRAINT fk1 REFERENCES ex2(x)
723 **     );
724 **
725 ** For foreign key "fk1", the from-table is "ex1" and the to-table is "ex2".
726 **
727 ** Each REFERENCES clause generates an instance of the following structure
728 ** which is attached to the from-table.  The to-table need not exist when
729 ** the from-table is created.  The existance of the to-table is not checked
730 ** until an attempt is made to insert data into the from-table.
731 **
732 ** The sqlite.aFKey hash table stores pointers to this structure
733 ** given the name of a to-table.  For each to-table, all foreign keys
734 ** associated with that table are on a linked list using the FKey.pNextTo
735 ** field.
736 */
737 struct FKey {
738   Table *pFrom;     /* The table that constains the REFERENCES clause */
739   FKey *pNextFrom;  /* Next foreign key in pFrom */
740   char *zTo;        /* Name of table that the key points to */
741   FKey *pNextTo;    /* Next foreign key that points to zTo */
742   int nCol;         /* Number of columns in this key */
743   struct sColMap {  /* Mapping of columns in pFrom to columns in zTo */
744     int iFrom;         /* Index of column in pFrom */
745     char *zCol;        /* Name of column in zTo.  If 0 use PRIMARY KEY */
746   } *aCol;          /* One entry for each of nCol column s */
747   u8 isDeferred;    /* True if constraint checking is deferred till COMMIT */
748   u8 updateConf;    /* How to resolve conflicts that occur on UPDATE */
749   u8 deleteConf;    /* How to resolve conflicts that occur on DELETE */
750   u8 insertConf;    /* How to resolve conflicts that occur on INSERT */
751 };
752 
753 /*
754 ** SQLite supports many different ways to resolve a contraint
755 ** error.  ROLLBACK processing means that a constraint violation
756 ** causes the operation in process to fail and for the current transaction
757 ** to be rolled back.  ABORT processing means the operation in process
758 ** fails and any prior changes from that one operation are backed out,
759 ** but the transaction is not rolled back.  FAIL processing means that
760 ** the operation in progress stops and returns an error code.  But prior
761 ** changes due to the same operation are not backed out and no rollback
762 ** occurs.  IGNORE means that the particular row that caused the constraint
763 ** error is not inserted or updated.  Processing continues and no error
764 ** is returned.  REPLACE means that preexisting database rows that caused
765 ** a UNIQUE constraint violation are removed so that the new insert or
766 ** update can proceed.  Processing continues and no error is reported.
767 **
768 ** RESTRICT, SETNULL, and CASCADE actions apply only to foreign keys.
769 ** RESTRICT is the same as ABORT for IMMEDIATE foreign keys and the
770 ** same as ROLLBACK for DEFERRED keys.  SETNULL means that the foreign
771 ** key is set to NULL.  CASCADE means that a DELETE or UPDATE of the
772 ** referenced table row is propagated into the row that holds the
773 ** foreign key.
774 **
775 ** The following symbolic values are used to record which type
776 ** of action to take.
777 */
778 #define OE_None     0   /* There is no constraint to check */
779 #define OE_Rollback 1   /* Fail the operation and rollback the transaction */
780 #define OE_Abort    2   /* Back out changes but do no rollback transaction */
781 #define OE_Fail     3   /* Stop the operation but leave all prior changes */
782 #define OE_Ignore   4   /* Ignore the error. Do not do the INSERT or UPDATE */
783 #define OE_Replace  5   /* Delete existing record, then do INSERT or UPDATE */
784 
785 #define OE_Restrict 6   /* OE_Abort for IMMEDIATE, OE_Rollback for DEFERRED */
786 #define OE_SetNull  7   /* Set the foreign key value to NULL */
787 #define OE_SetDflt  8   /* Set the foreign key value to its default */
788 #define OE_Cascade  9   /* Cascade the changes */
789 
790 #define OE_Default  99  /* Do whatever the default action is */
791 
792 
793 /*
794 ** An instance of the following structure is passed as the first
795 ** argument to sqlite3VdbeKeyCompare and is used to control the
796 ** comparison of the two index keys.
797 **
798 ** If the KeyInfo.incrKey value is true and the comparison would
799 ** otherwise be equal, then return a result as if the second key
800 ** were larger.
801 */
802 struct KeyInfo {
803   sqlite3 *db;        /* The database connection */
804   u8 enc;             /* Text encoding - one of the TEXT_Utf* values */
805   u8 incrKey;         /* Increase 2nd key by epsilon before comparison */
806   int nField;         /* Number of entries in aColl[] */
807   u8 *aSortOrder;     /* If defined an aSortOrder[i] is true, sort DESC */
808   CollSeq *aColl[1];  /* Collating sequence for each term of the key */
809 };
810 
811 /*
812 ** Each SQL index is represented in memory by an
813 ** instance of the following structure.
814 **
815 ** The columns of the table that are to be indexed are described
816 ** by the aiColumn[] field of this structure.  For example, suppose
817 ** we have the following table and index:
818 **
819 **     CREATE TABLE Ex1(c1 int, c2 int, c3 text);
820 **     CREATE INDEX Ex2 ON Ex1(c3,c1);
821 **
822 ** In the Table structure describing Ex1, nCol==3 because there are
823 ** three columns in the table.  In the Index structure describing
824 ** Ex2, nColumn==2 since 2 of the 3 columns of Ex1 are indexed.
825 ** The value of aiColumn is {2, 0}.  aiColumn[0]==2 because the
826 ** first column to be indexed (c3) has an index of 2 in Ex1.aCol[].
827 ** The second column to be indexed (c1) has an index of 0 in
828 ** Ex1.aCol[], hence Ex2.aiColumn[1]==0.
829 **
830 ** The Index.onError field determines whether or not the indexed columns
831 ** must be unique and what to do if they are not.  When Index.onError=OE_None,
832 ** it means this is not a unique index.  Otherwise it is a unique index
833 ** and the value of Index.onError indicate the which conflict resolution
834 ** algorithm to employ whenever an attempt is made to insert a non-unique
835 ** element.
836 */
837 struct Index {
838   char *zName;     /* Name of this index */
839   int nColumn;     /* Number of columns in the table used by this index */
840   int *aiColumn;   /* Which columns are used by this index.  1st is 0 */
841   unsigned *aiRowEst; /* Result of ANALYZE: Est. rows selected by each column */
842   Table *pTable;   /* The SQL table being indexed */
843   int tnum;        /* Page containing root of this index in database file */
844   u8 onError;      /* OE_Abort, OE_Ignore, OE_Replace, or OE_None */
845   u8 autoIndex;    /* True if is automatically created (ex: by UNIQUE) */
846   char *zColAff;   /* String defining the affinity of each column */
847   Index *pNext;    /* The next index associated with the same table */
848   Schema *pSchema; /* Schema containing this index */
849   u8 *aSortOrder;  /* Array of size Index.nColumn. True==DESC, False==ASC */
850   char **azColl;   /* Array of collation sequence names for index */
851 };
852 
853 /*
854 ** Each token coming out of the lexer is an instance of
855 ** this structure.  Tokens are also used as part of an expression.
856 **
857 ** Note if Token.z==0 then Token.dyn and Token.n are undefined and
858 ** may contain random values.  Do not make any assuptions about Token.dyn
859 ** and Token.n when Token.z==0.
860 */
861 struct Token {
862   const unsigned char *z; /* Text of the token.  Not NULL-terminated! */
863   unsigned dyn  : 1;      /* True for malloced memory, false for static */
864   unsigned n    : 31;     /* Number of characters in this token */
865 };
866 
867 /*
868 ** An instance of this structure contains information needed to generate
869 ** code for a SELECT that contains aggregate functions.
870 **
871 ** If Expr.op==TK_AGG_COLUMN or TK_AGG_FUNCTION then Expr.pAggInfo is a
872 ** pointer to this structure.  The Expr.iColumn field is the index in
873 ** AggInfo.aCol[] or AggInfo.aFunc[] of information needed to generate
874 ** code for that node.
875 **
876 ** AggInfo.pGroupBy and AggInfo.aFunc.pExpr point to fields within the
877 ** original Select structure that describes the SELECT statement.  These
878 ** fields do not need to be freed when deallocating the AggInfo structure.
879 */
880 struct AggInfo {
881   u8 directMode;          /* Direct rendering mode means take data directly
882                           ** from source tables rather than from accumulators */
883   u8 useSortingIdx;       /* In direct mode, reference the sorting index rather
884                           ** than the source table */
885   int sortingIdx;         /* Cursor number of the sorting index */
886   ExprList *pGroupBy;     /* The group by clause */
887   int nSortingColumn;     /* Number of columns in the sorting index */
888   struct AggInfo_col {    /* For each column used in source tables */
889     Table *pTab;             /* Source table */
890     int iTable;              /* Cursor number of the source table */
891     int iColumn;             /* Column number within the source table */
892     int iSorterColumn;       /* Column number in the sorting index */
893     int iMem;                /* Memory location that acts as accumulator */
894     Expr *pExpr;             /* The original expression */
895   } *aCol;
896   int nColumn;            /* Number of used entries in aCol[] */
897   int nColumnAlloc;       /* Number of slots allocated for aCol[] */
898   int nAccumulator;       /* Number of columns that show through to the output.
899                           ** Additional columns are used only as parameters to
900                           ** aggregate functions */
901   struct AggInfo_func {   /* For each aggregate function */
902     Expr *pExpr;             /* Expression encoding the function */
903     FuncDef *pFunc;          /* The aggregate function implementation */
904     int iMem;                /* Memory location that acts as accumulator */
905     int iDistinct;           /* Ephermeral table used to enforce DISTINCT */
906   } *aFunc;
907   int nFunc;              /* Number of entries in aFunc[] */
908   int nFuncAlloc;         /* Number of slots allocated for aFunc[] */
909 };
910 
911 /*
912 ** Each node of an expression in the parse tree is an instance
913 ** of this structure.
914 **
915 ** Expr.op is the opcode.  The integer parser token codes are reused
916 ** as opcodes here.  For example, the parser defines TK_GE to be an integer
917 ** code representing the ">=" operator.  This same integer code is reused
918 ** to represent the greater-than-or-equal-to operator in the expression
919 ** tree.
920 **
921 ** Expr.pRight and Expr.pLeft are subexpressions.  Expr.pList is a list
922 ** of argument if the expression is a function.
923 **
924 ** Expr.token is the operator token for this node.  For some expressions
925 ** that have subexpressions, Expr.token can be the complete text that gave
926 ** rise to the Expr.  In the latter case, the token is marked as being
927 ** a compound token.
928 **
929 ** An expression of the form ID or ID.ID refers to a column in a table.
930 ** For such expressions, Expr.op is set to TK_COLUMN and Expr.iTable is
931 ** the integer cursor number of a VDBE cursor pointing to that table and
932 ** Expr.iColumn is the column number for the specific column.  If the
933 ** expression is used as a result in an aggregate SELECT, then the
934 ** value is also stored in the Expr.iAgg column in the aggregate so that
935 ** it can be accessed after all aggregates are computed.
936 **
937 ** If the expression is a function, the Expr.iTable is an integer code
938 ** representing which function.  If the expression is an unbound variable
939 ** marker (a question mark character '?' in the original SQL) then the
940 ** Expr.iTable holds the index number for that variable.
941 **
942 ** If the expression is a subquery then Expr.iColumn holds an integer
943 ** register number containing the result of the subquery.  If the
944 ** subquery gives a constant result, then iTable is -1.  If the subquery
945 ** gives a different answer at different times during statement processing
946 ** then iTable is the address of a subroutine that computes the subquery.
947 **
948 ** The Expr.pSelect field points to a SELECT statement.  The SELECT might
949 ** be the right operand of an IN operator.  Or, if a scalar SELECT appears
950 ** in an expression the opcode is TK_SELECT and Expr.pSelect is the only
951 ** operand.
952 **
953 ** If the Expr is of type OP_Column, and the table it is selecting from
954 ** is a disk table or the "old.*" pseudo-table, then pTab points to the
955 ** corresponding table definition.
956 */
957 struct Expr {
958   u8 op;                 /* Operation performed by this node */
959   char affinity;         /* The affinity of the column or 0 if not a column */
960   u16 flags;             /* Various flags.  See below */
961   CollSeq *pColl;        /* The collation type of the column or 0 */
962   Expr *pLeft, *pRight;  /* Left and right subnodes */
963   ExprList *pList;       /* A list of expressions used as function arguments
964                          ** or in "<expr> IN (<expr-list)" */
965   Token token;           /* An operand token */
966   Token span;            /* Complete text of the expression */
967   int iTable, iColumn;   /* When op==TK_COLUMN, then this expr node means the
968                          ** iColumn-th field of the iTable-th table. */
969   AggInfo *pAggInfo;     /* Used by TK_AGG_COLUMN and TK_AGG_FUNCTION */
970   int iAgg;              /* Which entry in pAggInfo->aCol[] or ->aFunc[] */
971   int iRightJoinTable;   /* If EP_FromJoin, the right table of the join */
972   Select *pSelect;       /* When the expression is a sub-select.  Also the
973                          ** right side of "<expr> IN (<select>)" */
974   Table *pTab;           /* Table for OP_Column expressions. */
975   Schema *pSchema;
976 #if SQLITE_MAX_EXPR_DEPTH>0
977   int nHeight;           /* Height of the tree headed by this node */
978 #endif
979 };
980 
981 /*
982 ** The following are the meanings of bits in the Expr.flags field.
983 */
984 #define EP_FromJoin     0x01  /* Originated in ON or USING clause of a join */
985 #define EP_Agg          0x02  /* Contains one or more aggregate functions */
986 #define EP_Resolved     0x04  /* IDs have been resolved to COLUMNs */
987 #define EP_Error        0x08  /* Expression contains one or more errors */
988 #define EP_Distinct     0x10  /* Aggregate function with DISTINCT keyword */
989 #define EP_VarSelect    0x20  /* pSelect is correlated, not constant */
990 #define EP_Dequoted     0x40  /* True if the string has been dequoted */
991 #define EP_InfixFunc    0x80  /* True for an infix function: LIKE, GLOB, etc */
992 #define EP_ExpCollate  0x100  /* Collating sequence specified explicitly */
993 
994 /*
995 ** These macros can be used to test, set, or clear bits in the
996 ** Expr.flags field.
997 */
998 #define ExprHasProperty(E,P)     (((E)->flags&(P))==(P))
999 #define ExprHasAnyProperty(E,P)  (((E)->flags&(P))!=0)
1000 #define ExprSetProperty(E,P)     (E)->flags|=(P)
1001 #define ExprClearProperty(E,P)   (E)->flags&=~(P)
1002 
1003 /*
1004 ** A list of expressions.  Each expression may optionally have a
1005 ** name.  An expr/name combination can be used in several ways, such
1006 ** as the list of "expr AS ID" fields following a "SELECT" or in the
1007 ** list of "ID = expr" items in an UPDATE.  A list of expressions can
1008 ** also be used as the argument to a function, in which case the a.zName
1009 ** field is not used.
1010 */
1011 struct ExprList {
1012   int nExpr;             /* Number of expressions on the list */
1013   int nAlloc;            /* Number of entries allocated below */
1014   int iECursor;          /* VDBE Cursor associated with this ExprList */
1015   struct ExprList_item {
1016     Expr *pExpr;           /* The list of expressions */
1017     char *zName;           /* Token associated with this expression */
1018     u8 sortOrder;          /* 1 for DESC or 0 for ASC */
1019     u8 isAgg;              /* True if this is an aggregate like count(*) */
1020     u8 done;               /* A flag to indicate when processing is finished */
1021   } *a;                  /* One entry for each expression */
1022 };
1023 
1024 /*
1025 ** An instance of this structure can hold a simple list of identifiers,
1026 ** such as the list "a,b,c" in the following statements:
1027 **
1028 **      INSERT INTO t(a,b,c) VALUES ...;
1029 **      CREATE INDEX idx ON t(a,b,c);
1030 **      CREATE TRIGGER trig BEFORE UPDATE ON t(a,b,c) ...;
1031 **
1032 ** The IdList.a.idx field is used when the IdList represents the list of
1033 ** column names after a table name in an INSERT statement.  In the statement
1034 **
1035 **     INSERT INTO t(a,b,c) ...
1036 **
1037 ** If "a" is the k-th column of table "t", then IdList.a[0].idx==k.
1038 */
1039 struct IdList {
1040   struct IdList_item {
1041     char *zName;      /* Name of the identifier */
1042     int idx;          /* Index in some Table.aCol[] of a column named zName */
1043   } *a;
1044   int nId;         /* Number of identifiers on the list */
1045   int nAlloc;      /* Number of entries allocated for a[] below */
1046 };
1047 
1048 /*
1049 ** The bitmask datatype defined below is used for various optimizations.
1050 **
1051 ** Changing this from a 64-bit to a 32-bit type limits the number of
1052 ** tables in a join to 32 instead of 64.  But it also reduces the size
1053 ** of the library by 738 bytes on ix86.
1054 */
1055 typedef u64 Bitmask;
1056 
1057 /*
1058 ** The following structure describes the FROM clause of a SELECT statement.
1059 ** Each table or subquery in the FROM clause is a separate element of
1060 ** the SrcList.a[] array.
1061 **
1062 ** With the addition of multiple database support, the following structure
1063 ** can also be used to describe a particular table such as the table that
1064 ** is modified by an INSERT, DELETE, or UPDATE statement.  In standard SQL,
1065 ** such a table must be a simple name: ID.  But in SQLite, the table can
1066 ** now be identified by a database name, a dot, then the table name: ID.ID.
1067 **
1068 ** The jointype starts out showing the join type between the current table
1069 ** and the next table on the list.  The parser builds the list this way.
1070 ** But sqlite3SrcListShiftJoinType() later shifts the jointypes so that each
1071 ** jointype expresses the join between the table and the previous table.
1072 */
1073 struct SrcList {
1074   i16 nSrc;        /* Number of tables or subqueries in the FROM clause */
1075   i16 nAlloc;      /* Number of entries allocated in a[] below */
1076   struct SrcList_item {
1077     char *zDatabase;  /* Name of database holding this table */
1078     char *zName;      /* Name of the table */
1079     char *zAlias;     /* The "B" part of a "A AS B" phrase.  zName is the "A" */
1080     Table *pTab;      /* An SQL table corresponding to zName */
1081     Select *pSelect;  /* A SELECT statement used in place of a table name */
1082     u8 isPopulated;   /* Temporary table associated with SELECT is populated */
1083     u8 jointype;      /* Type of join between this able and the previous */
1084     int iCursor;      /* The VDBE cursor number used to access this table */
1085     Expr *pOn;        /* The ON clause of a join */
1086     IdList *pUsing;   /* The USING clause of a join */
1087     Bitmask colUsed;  /* Bit N (1<<N) set if column N or pTab is used */
1088   } a[1];             /* One entry for each identifier on the list */
1089 };
1090 
1091 /*
1092 ** Permitted values of the SrcList.a.jointype field
1093 */
1094 #define JT_INNER     0x0001    /* Any kind of inner or cross join */
1095 #define JT_CROSS     0x0002    /* Explicit use of the CROSS keyword */
1096 #define JT_NATURAL   0x0004    /* True for a "natural" join */
1097 #define JT_LEFT      0x0008    /* Left outer join */
1098 #define JT_RIGHT     0x0010    /* Right outer join */
1099 #define JT_OUTER     0x0020    /* The "OUTER" keyword is present */
1100 #define JT_ERROR     0x0040    /* unknown or unsupported join type */
1101 
1102 /*
1103 ** For each nested loop in a WHERE clause implementation, the WhereInfo
1104 ** structure contains a single instance of this structure.  This structure
1105 ** is intended to be private the the where.c module and should not be
1106 ** access or modified by other modules.
1107 **
1108 ** The pIdxInfo and pBestIdx fields are used to help pick the best
1109 ** index on a virtual table.  The pIdxInfo pointer contains indexing
1110 ** information for the i-th table in the FROM clause before reordering.
1111 ** All the pIdxInfo pointers are freed by whereInfoFree() in where.c.
1112 ** The pBestIdx pointer is a copy of pIdxInfo for the i-th table after
1113 ** FROM clause ordering.  This is a little confusing so I will repeat
1114 ** it in different words.  WhereInfo.a[i].pIdxInfo is index information
1115 ** for WhereInfo.pTabList.a[i].  WhereInfo.a[i].pBestInfo is the
1116 ** index information for the i-th loop of the join.  pBestInfo is always
1117 ** either NULL or a copy of some pIdxInfo.  So for cleanup it is
1118 ** sufficient to free all of the pIdxInfo pointers.
1119 **
1120 */
1121 struct WhereLevel {
1122   int iFrom;            /* Which entry in the FROM clause */
1123   int flags;            /* Flags associated with this level */
1124   int iMem;             /* First memory cell used by this level */
1125   int iLeftJoin;        /* Memory cell used to implement LEFT OUTER JOIN */
1126   Index *pIdx;          /* Index used.  NULL if no index */
1127   int iTabCur;          /* The VDBE cursor used to access the table */
1128   int iIdxCur;          /* The VDBE cursor used to acesss pIdx */
1129   int brk;              /* Jump here to break out of the loop */
1130   int nxt;              /* Jump here to start the next IN combination */
1131   int cont;             /* Jump here to continue with the next loop cycle */
1132   int top;              /* First instruction of interior of the loop */
1133   int op, p1, p2;       /* Opcode used to terminate the loop */
1134   int nEq;              /* Number of == or IN constraints on this loop */
1135   int nIn;              /* Number of IN operators constraining this loop */
1136   struct InLoop {
1137     int iCur;              /* The VDBE cursor used by this IN operator */
1138     int topAddr;           /* Top of the IN loop */
1139   } *aInLoop;           /* Information about each nested IN operator */
1140   sqlite3_index_info *pBestIdx;  /* Index information for this level */
1141 
1142   /* The following field is really not part of the current level.  But
1143   ** we need a place to cache index information for each table in the
1144   ** FROM clause and the WhereLevel structure is a convenient place.
1145   */
1146   sqlite3_index_info *pIdxInfo;  /* Index info for n-th source table */
1147 };
1148 
1149 /*
1150 ** The WHERE clause processing routine has two halves.  The
1151 ** first part does the start of the WHERE loop and the second
1152 ** half does the tail of the WHERE loop.  An instance of
1153 ** this structure is returned by the first half and passed
1154 ** into the second half to give some continuity.
1155 */
1156 struct WhereInfo {
1157   Parse *pParse;
1158   SrcList *pTabList;   /* List of tables in the join */
1159   int iTop;            /* The very beginning of the WHERE loop */
1160   int iContinue;       /* Jump here to continue with next record */
1161   int iBreak;          /* Jump here to break out of the loop */
1162   int nLevel;          /* Number of nested loop */
1163   sqlite3_index_info **apInfo;  /* Array of pointers to index info structures */
1164   WhereLevel a[1];     /* Information about each nest loop in the WHERE */
1165 };
1166 
1167 /*
1168 ** A NameContext defines a context in which to resolve table and column
1169 ** names.  The context consists of a list of tables (the pSrcList) field and
1170 ** a list of named expression (pEList).  The named expression list may
1171 ** be NULL.  The pSrc corresponds to the FROM clause of a SELECT or
1172 ** to the table being operated on by INSERT, UPDATE, or DELETE.  The
1173 ** pEList corresponds to the result set of a SELECT and is NULL for
1174 ** other statements.
1175 **
1176 ** NameContexts can be nested.  When resolving names, the inner-most
1177 ** context is searched first.  If no match is found, the next outer
1178 ** context is checked.  If there is still no match, the next context
1179 ** is checked.  This process continues until either a match is found
1180 ** or all contexts are check.  When a match is found, the nRef member of
1181 ** the context containing the match is incremented.
1182 **
1183 ** Each subquery gets a new NameContext.  The pNext field points to the
1184 ** NameContext in the parent query.  Thus the process of scanning the
1185 ** NameContext list corresponds to searching through successively outer
1186 ** subqueries looking for a match.
1187 */
1188 struct NameContext {
1189   Parse *pParse;       /* The parser */
1190   SrcList *pSrcList;   /* One or more tables used to resolve names */
1191   ExprList *pEList;    /* Optional list of named expressions */
1192   int nRef;            /* Number of names resolved by this context */
1193   int nErr;            /* Number of errors encountered while resolving names */
1194   u8 allowAgg;         /* Aggregate functions allowed here */
1195   u8 hasAgg;           /* True if aggregates are seen */
1196   u8 isCheck;          /* True if resolving names in a CHECK constraint */
1197   int nDepth;          /* Depth of subquery recursion. 1 for no recursion */
1198   AggInfo *pAggInfo;   /* Information about aggregates at this level */
1199   NameContext *pNext;  /* Next outer name context.  NULL for outermost */
1200 };
1201 
1202 /*
1203 ** An instance of the following structure contains all information
1204 ** needed to generate code for a single SELECT statement.
1205 **
1206 ** nLimit is set to -1 if there is no LIMIT clause.  nOffset is set to 0.
1207 ** If there is a LIMIT clause, the parser sets nLimit to the value of the
1208 ** limit and nOffset to the value of the offset (or 0 if there is not
1209 ** offset).  But later on, nLimit and nOffset become the memory locations
1210 ** in the VDBE that record the limit and offset counters.
1211 **
1212 ** addrOpenEphm[] entries contain the address of OP_OpenEphemeral opcodes.
1213 ** These addresses must be stored so that we can go back and fill in
1214 ** the P3_KEYINFO and P2 parameters later.  Neither the KeyInfo nor
1215 ** the number of columns in P2 can be computed at the same time
1216 ** as the OP_OpenEphm instruction is coded because not
1217 ** enough information about the compound query is known at that point.
1218 ** The KeyInfo for addrOpenTran[0] and [1] contains collating sequences
1219 ** for the result set.  The KeyInfo for addrOpenTran[2] contains collating
1220 ** sequences for the ORDER BY clause.
1221 */
1222 struct Select {
1223   ExprList *pEList;      /* The fields of the result */
1224   u8 op;                 /* One of: TK_UNION TK_ALL TK_INTERSECT TK_EXCEPT */
1225   u8 isDistinct;         /* True if the DISTINCT keyword is present */
1226   u8 isResolved;         /* True once sqlite3SelectResolve() has run. */
1227   u8 isAgg;              /* True if this is an aggregate query */
1228   u8 usesEphm;           /* True if uses an OpenEphemeral opcode */
1229   u8 disallowOrderBy;    /* Do not allow an ORDER BY to be attached if TRUE */
1230   char affinity;         /* MakeRecord with this affinity for SRT_Set */
1231   SrcList *pSrc;         /* The FROM clause */
1232   Expr *pWhere;          /* The WHERE clause */
1233   ExprList *pGroupBy;    /* The GROUP BY clause */
1234   Expr *pHaving;         /* The HAVING clause */
1235   ExprList *pOrderBy;    /* The ORDER BY clause */
1236   Select *pPrior;        /* Prior select in a compound select statement */
1237   Select *pRightmost;    /* Right-most select in a compound select statement */
1238   Expr *pLimit;          /* LIMIT expression. NULL means not used. */
1239   Expr *pOffset;         /* OFFSET expression. NULL means not used. */
1240   int iLimit, iOffset;   /* Memory registers holding LIMIT & OFFSET counters */
1241   int addrOpenEphm[3];   /* OP_OpenEphem opcodes related to this select */
1242 };
1243 
1244 /*
1245 ** The results of a select can be distributed in several ways.
1246 */
1247 #define SRT_Union        1  /* Store result as keys in an index */
1248 #define SRT_Except       2  /* Remove result from a UNION index */
1249 #define SRT_Discard      3  /* Do not save the results anywhere */
1250 
1251 /* The ORDER BY clause is ignored for all of the above */
1252 #define IgnorableOrderby(X) (X<=SRT_Discard)
1253 
1254 #define SRT_Callback     4  /* Invoke a callback with each row of result */
1255 #define SRT_Mem          5  /* Store result in a memory cell */
1256 #define SRT_Set          6  /* Store non-null results as keys in an index */
1257 #define SRT_Table        7  /* Store result as data with an automatic rowid */
1258 #define SRT_EphemTab     8  /* Create transient tab and store like SRT_Table */
1259 #define SRT_Subroutine   9  /* Call a subroutine to handle results */
1260 #define SRT_Exists      10  /* Store 1 if the result is not empty */
1261 
1262 /*
1263 ** An SQL parser context.  A copy of this structure is passed through
1264 ** the parser and down into all the parser action routine in order to
1265 ** carry around information that is global to the entire parse.
1266 **
1267 ** The structure is divided into two parts.  When the parser and code
1268 ** generate call themselves recursively, the first part of the structure
1269 ** is constant but the second part is reset at the beginning and end of
1270 ** each recursion.
1271 **
1272 ** The nTableLock and aTableLock variables are only used if the shared-cache
1273 ** feature is enabled (if sqlite3Tsd()->useSharedData is true). They are
1274 ** used to store the set of table-locks required by the statement being
1275 ** compiled. Function sqlite3TableLock() is used to add entries to the
1276 ** list.
1277 */
1278 struct Parse {
1279   sqlite3 *db;         /* The main database structure */
1280   int rc;              /* Return code from execution */
1281   char *zErrMsg;       /* An error message */
1282   Vdbe *pVdbe;         /* An engine for executing database bytecode */
1283   u8 colNamesSet;      /* TRUE after OP_ColumnName has been issued to pVdbe */
1284   u8 nameClash;        /* A permanent table name clashes with temp table name */
1285   u8 checkSchema;      /* Causes schema cookie check after an error */
1286   u8 nested;           /* Number of nested calls to the parser/code generator */
1287   u8 parseError;       /* True after a parsing error.  Ticket #1794 */
1288   int nErr;            /* Number of errors seen */
1289   int nTab;            /* Number of previously allocated VDBE cursors */
1290   int nMem;            /* Number of memory cells used so far */
1291   int nSet;            /* Number of sets used so far */
1292   int ckOffset;        /* Stack offset to data used by CHECK constraints */
1293   u32 writeMask;       /* Start a write transaction on these databases */
1294   u32 cookieMask;      /* Bitmask of schema verified databases */
1295   int cookieGoto;      /* Address of OP_Goto to cookie verifier subroutine */
1296   int cookieValue[SQLITE_MAX_ATTACHED+2];  /* Values of cookies to verify */
1297 #ifndef SQLITE_OMIT_SHARED_CACHE
1298   int nTableLock;        /* Number of locks in aTableLock */
1299   TableLock *aTableLock; /* Required table locks for shared-cache mode */
1300 #endif
1301 
1302   /* Above is constant between recursions.  Below is reset before and after
1303   ** each recursion */
1304 
1305   int nVar;            /* Number of '?' variables seen in the SQL so far */
1306   int nVarExpr;        /* Number of used slots in apVarExpr[] */
1307   int nVarExprAlloc;   /* Number of allocated slots in apVarExpr[] */
1308   Expr **apVarExpr;    /* Pointers to :aaa and $aaaa wildcard expressions */
1309   u8 explain;          /* True if the EXPLAIN flag is found on the query */
1310   Token sErrToken;     /* The token at which the error occurred */
1311   Token sNameToken;    /* Token with unqualified schema object name */
1312   Token sLastToken;    /* The last token parsed */
1313   const char *zSql;    /* All SQL text */
1314   const char *zTail;   /* All SQL text past the last semicolon parsed */
1315   Table *pNewTable;    /* A table being constructed by CREATE TABLE */
1316   Trigger *pNewTrigger;     /* Trigger under construct by a CREATE TRIGGER */
1317   TriggerStack *trigStack;  /* Trigger actions being coded */
1318   const char *zAuthContext; /* The 6th parameter to db->xAuth callbacks */
1319 #ifndef SQLITE_OMIT_VIRTUALTABLE
1320   Token sArg;                /* Complete text of a module argument */
1321   u8 declareVtab;            /* True if inside sqlite3_declare_vtab() */
1322   Table *pVirtualLock;       /* Require virtual table lock on this table */
1323 #endif
1324 #if SQLITE_MAX_EXPR_DEPTH>0
1325   int nHeight;            /* Expression tree height of current sub-select */
1326 #endif
1327 };
1328 
1329 #ifdef SQLITE_OMIT_VIRTUALTABLE
1330   #define IN_DECLARE_VTAB 0
1331 #else
1332   #define IN_DECLARE_VTAB (pParse->declareVtab)
1333 #endif
1334 
1335 /*
1336 ** An instance of the following structure can be declared on a stack and used
1337 ** to save the Parse.zAuthContext value so that it can be restored later.
1338 */
1339 struct AuthContext {
1340   const char *zAuthContext;   /* Put saved Parse.zAuthContext here */
1341   Parse *pParse;              /* The Parse structure */
1342 };
1343 
1344 /*
1345 ** Bitfield flags for P2 value in OP_Insert and OP_Delete
1346 */
1347 #define OPFLAG_NCHANGE   1    /* Set to update db->nChange */
1348 #define OPFLAG_LASTROWID 2    /* Set to update db->lastRowid */
1349 #define OPFLAG_ISUPDATE  4    /* This OP_Insert is an sql UPDATE */
1350 #define OPFLAG_APPEND    8    /* This is likely to be an append */
1351 
1352 /*
1353  * Each trigger present in the database schema is stored as an instance of
1354  * struct Trigger.
1355  *
1356  * Pointers to instances of struct Trigger are stored in two ways.
1357  * 1. In the "trigHash" hash table (part of the sqlite3* that represents the
1358  *    database). This allows Trigger structures to be retrieved by name.
1359  * 2. All triggers associated with a single table form a linked list, using the
1360  *    pNext member of struct Trigger. A pointer to the first element of the
1361  *    linked list is stored as the "pTrigger" member of the associated
1362  *    struct Table.
1363  *
1364  * The "step_list" member points to the first element of a linked list
1365  * containing the SQL statements specified as the trigger program.
1366  */
1367 struct Trigger {
1368   char *name;             /* The name of the trigger                        */
1369   char *table;            /* The table or view to which the trigger applies */
1370   u8 op;                  /* One of TK_DELETE, TK_UPDATE, TK_INSERT         */
1371   u8 tr_tm;               /* One of TRIGGER_BEFORE, TRIGGER_AFTER */
1372   Expr *pWhen;            /* The WHEN clause of the expresion (may be NULL) */
1373   IdList *pColumns;       /* If this is an UPDATE OF <column-list> trigger,
1374                              the <column-list> is stored here */
1375   Token nameToken;        /* Token containing zName. Use during parsing only */
1376   Schema *pSchema;        /* Schema containing the trigger */
1377   Schema *pTabSchema;     /* Schema containing the table */
1378   TriggerStep *step_list; /* Link list of trigger program steps             */
1379   Trigger *pNext;         /* Next trigger associated with the table */
1380 };
1381 
1382 /*
1383 ** A trigger is either a BEFORE or an AFTER trigger.  The following constants
1384 ** determine which.
1385 **
1386 ** If there are multiple triggers, you might of some BEFORE and some AFTER.
1387 ** In that cases, the constants below can be ORed together.
1388 */
1389 #define TRIGGER_BEFORE  1
1390 #define TRIGGER_AFTER   2
1391 
1392 /*
1393  * An instance of struct TriggerStep is used to store a single SQL statement
1394  * that is a part of a trigger-program.
1395  *
1396  * Instances of struct TriggerStep are stored in a singly linked list (linked
1397  * using the "pNext" member) referenced by the "step_list" member of the
1398  * associated struct Trigger instance. The first element of the linked list is
1399  * the first step of the trigger-program.
1400  *
1401  * The "op" member indicates whether this is a "DELETE", "INSERT", "UPDATE" or
1402  * "SELECT" statement. The meanings of the other members is determined by the
1403  * value of "op" as follows:
1404  *
1405  * (op == TK_INSERT)
1406  * orconf    -> stores the ON CONFLICT algorithm
1407  * pSelect   -> If this is an INSERT INTO ... SELECT ... statement, then
1408  *              this stores a pointer to the SELECT statement. Otherwise NULL.
1409  * target    -> A token holding the name of the table to insert into.
1410  * pExprList -> If this is an INSERT INTO ... VALUES ... statement, then
1411  *              this stores values to be inserted. Otherwise NULL.
1412  * pIdList   -> If this is an INSERT INTO ... (<column-names>) VALUES ...
1413  *              statement, then this stores the column-names to be
1414  *              inserted into.
1415  *
1416  * (op == TK_DELETE)
1417  * target    -> A token holding the name of the table to delete from.
1418  * pWhere    -> The WHERE clause of the DELETE statement if one is specified.
1419  *              Otherwise NULL.
1420  *
1421  * (op == TK_UPDATE)
1422  * target    -> A token holding the name of the table to update rows of.
1423  * pWhere    -> The WHERE clause of the UPDATE statement if one is specified.
1424  *              Otherwise NULL.
1425  * pExprList -> A list of the columns to update and the expressions to update
1426  *              them to. See sqlite3Update() documentation of "pChanges"
1427  *              argument.
1428  *
1429  */
1430 struct TriggerStep {
1431   int op;              /* One of TK_DELETE, TK_UPDATE, TK_INSERT, TK_SELECT */
1432   int orconf;          /* OE_Rollback etc. */
1433   Trigger *pTrig;      /* The trigger that this step is a part of */
1434 
1435   Select *pSelect;     /* Valid for SELECT and sometimes
1436                           INSERT steps (when pExprList == 0) */
1437   Token target;        /* Valid for DELETE, UPDATE, INSERT steps */
1438   Expr *pWhere;        /* Valid for DELETE, UPDATE steps */
1439   ExprList *pExprList; /* Valid for UPDATE statements and sometimes
1440                            INSERT steps (when pSelect == 0)         */
1441   IdList *pIdList;     /* Valid for INSERT statements only */
1442   TriggerStep *pNext;  /* Next in the link-list */
1443   TriggerStep *pLast;  /* Last element in link-list. Valid for 1st elem only */
1444 };
1445 
1446 /*
1447  * An instance of struct TriggerStack stores information required during code
1448  * generation of a single trigger program. While the trigger program is being
1449  * coded, its associated TriggerStack instance is pointed to by the
1450  * "pTriggerStack" member of the Parse structure.
1451  *
1452  * The pTab member points to the table that triggers are being coded on. The
1453  * newIdx member contains the index of the vdbe cursor that points at the temp
1454  * table that stores the new.* references. If new.* references are not valid
1455  * for the trigger being coded (for example an ON DELETE trigger), then newIdx
1456  * is set to -1. The oldIdx member is analogous to newIdx, for old.* references.
1457  *
1458  * The ON CONFLICT policy to be used for the trigger program steps is stored
1459  * as the orconf member. If this is OE_Default, then the ON CONFLICT clause
1460  * specified for individual triggers steps is used.
1461  *
1462  * struct TriggerStack has a "pNext" member, to allow linked lists to be
1463  * constructed. When coding nested triggers (triggers fired by other triggers)
1464  * each nested trigger stores its parent trigger's TriggerStack as the "pNext"
1465  * pointer. Once the nested trigger has been coded, the pNext value is restored
1466  * to the pTriggerStack member of the Parse stucture and coding of the parent
1467  * trigger continues.
1468  *
1469  * Before a nested trigger is coded, the linked list pointed to by the
1470  * pTriggerStack is scanned to ensure that the trigger is not about to be coded
1471  * recursively. If this condition is detected, the nested trigger is not coded.
1472  */
1473 struct TriggerStack {
1474   Table *pTab;         /* Table that triggers are currently being coded on */
1475   int newIdx;          /* Index of vdbe cursor to "new" temp table */
1476   int oldIdx;          /* Index of vdbe cursor to "old" temp table */
1477   int orconf;          /* Current orconf policy */
1478   int ignoreJump;      /* where to jump to for a RAISE(IGNORE) */
1479   Trigger *pTrigger;   /* The trigger currently being coded */
1480   TriggerStack *pNext; /* Next trigger down on the trigger stack */
1481 };
1482 
1483 /*
1484 ** The following structure contains information used by the sqliteFix...
1485 ** routines as they walk the parse tree to make database references
1486 ** explicit.
1487 */
1488 typedef struct DbFixer DbFixer;
1489 struct DbFixer {
1490   Parse *pParse;      /* The parsing context.  Error messages written here */
1491   const char *zDb;    /* Make sure all objects are contained in this database */
1492   const char *zType;  /* Type of the container - used for error messages */
1493   const Token *pName; /* Name of the container - used for error messages */
1494 };
1495 
1496 /*
1497 ** A pointer to this structure is used to communicate information
1498 ** from sqlite3Init and OP_ParseSchema into the sqlite3InitCallback.
1499 */
1500 typedef struct {
1501   sqlite3 *db;        /* The database being initialized */
1502   int iDb;            /* 0 for main database.  1 for TEMP, 2.. for ATTACHed */
1503   char **pzErrMsg;    /* Error message stored here */
1504   int rc;             /* Result code stored here */
1505 } InitData;
1506 
1507 /*
1508 ** Assuming zIn points to the first byte of a UTF-8 character,
1509 ** advance zIn to point to the first byte of the next UTF-8 character.
1510 */
1511 #define SQLITE_SKIP_UTF8(zIn) {                        \
1512   if( (*(zIn++))>=0xc0 ){                              \
1513     while( (*zIn & 0xc0)==0x80 ){ zIn++; }             \
1514   }                                                    \
1515 }
1516 
1517 /*
1518 ** The SQLITE_CORRUPT_BKPT macro can be either a constant (for production
1519 ** builds) or a function call (for debugging).  If it is a function call,
1520 ** it allows the operator to set a breakpoint at the spot where database
1521 ** corruption is first detected.
1522 */
1523 #ifdef SQLITE_DEBUG
1524   int sqlite3Corrupt(void);
1525 # define SQLITE_CORRUPT_BKPT sqlite3Corrupt()
1526 #else
1527 # define SQLITE_CORRUPT_BKPT SQLITE_CORRUPT
1528 #endif
1529 
1530 /*
1531 ** Internal function prototypes
1532 */
1533 int sqlite3StrICmp(const char *, const char *);
1534 int sqlite3StrNICmp(const char *, const char *, int);
1535 int sqlite3IsNumber(const char*, int*, u8);
1536 
1537 void *sqlite3MallocZero(unsigned);
1538 void *sqlite3DbMallocZero(sqlite3*, unsigned);
1539 void *sqlite3DbMallocRaw(sqlite3*, unsigned);
1540 char *sqlite3StrDup(const char*);
1541 char *sqlite3StrNDup(const char*, int);
1542 char *sqlite3DbStrDup(sqlite3*,const char*);
1543 char *sqlite3DbStrNDup(sqlite3*,const char*, int);
1544 void *sqlite3DbReallocOrFree(sqlite3 *, void *, int);
1545 void *sqlite3DbRealloc(sqlite3 *, void *, int);
1546 
1547 char *sqlite3MPrintf(sqlite3*,const char*, ...);
1548 char *sqlite3VMPrintf(sqlite3*,const char*, va_list);
1549 #if defined(SQLITE_TEST) || defined(SQLITE_DEBUG)
1550   void sqlite3DebugPrintf(const char*, ...);
1551   void *sqlite3TextToPtr(const char*);
1552 #endif
1553 void sqlite3SetString(char **, ...);
1554 void sqlite3ErrorMsg(Parse*, const char*, ...);
1555 void sqlite3ErrorClear(Parse*);
1556 void sqlite3Dequote(char*);
1557 void sqlite3DequoteExpr(sqlite3*, Expr*);
1558 int sqlite3KeywordCode(const unsigned char*, int);
1559 int sqlite3RunParser(Parse*, const char*, char **);
1560 void sqlite3FinishCoding(Parse*);
1561 Expr *sqlite3Expr(sqlite3*, int, Expr*, Expr*, const Token*);
1562 Expr *sqlite3PExpr(Parse*, int, Expr*, Expr*, const Token*);
1563 Expr *sqlite3RegisterExpr(Parse*,Token*);
1564 Expr *sqlite3ExprAnd(sqlite3*,Expr*, Expr*);
1565 void sqlite3ExprSpan(Expr*,Token*,Token*);
1566 Expr *sqlite3ExprFunction(Parse*,ExprList*, Token*);
1567 void sqlite3ExprAssignVarNumber(Parse*, Expr*);
1568 void sqlite3ExprDelete(Expr*);
1569 ExprList *sqlite3ExprListAppend(Parse*,ExprList*,Expr*,Token*);
1570 void sqlite3ExprListDelete(ExprList*);
1571 int sqlite3Init(sqlite3*, char**);
1572 int sqlite3InitCallback(void*, int, char**, char**);
1573 void sqlite3Pragma(Parse*,Token*,Token*,Token*,int);
1574 void sqlite3ResetInternalSchema(sqlite3*, int);
1575 void sqlite3BeginParse(Parse*,int);
1576 void sqlite3CommitInternalChanges(sqlite3*);
1577 Table *sqlite3ResultSetOfSelect(Parse*,char*,Select*);
1578 void sqlite3OpenMasterTable(Parse *, int);
1579 void sqlite3StartTable(Parse*,Token*,Token*,int,int,int,int);
1580 void sqlite3AddColumn(Parse*,Token*);
1581 void sqlite3AddNotNull(Parse*, int);
1582 void sqlite3AddPrimaryKey(Parse*, ExprList*, int, int, int);
1583 void sqlite3AddCheckConstraint(Parse*, Expr*);
1584 void sqlite3AddColumnType(Parse*,Token*);
1585 void sqlite3AddDefaultValue(Parse*,Expr*);
1586 void sqlite3AddCollateType(Parse*, const char*, int);
1587 void sqlite3EndTable(Parse*,Token*,Token*,Select*);
1588 
1589 void sqlite3CreateView(Parse*,Token*,Token*,Token*,Select*,int,int);
1590 
1591 #if !defined(SQLITE_OMIT_VIEW) || !defined(SQLITE_OMIT_VIRTUALTABLE)
1592   int sqlite3ViewGetColumnNames(Parse*,Table*);
1593 #else
1594 # define sqlite3ViewGetColumnNames(A,B) 0
1595 #endif
1596 
1597 void sqlite3DropTable(Parse*, SrcList*, int, int);
1598 void sqlite3DeleteTable(Table*);
1599 void sqlite3Insert(Parse*, SrcList*, ExprList*, Select*, IdList*, int);
1600 void *sqlite3ArrayAllocate(sqlite3*,void*,int,int,int*,int*,int*);
1601 IdList *sqlite3IdListAppend(sqlite3*, IdList*, Token*);
1602 int sqlite3IdListIndex(IdList*,const char*);
1603 SrcList *sqlite3SrcListAppend(sqlite3*, SrcList*, Token*, Token*);
1604 SrcList *sqlite3SrcListAppendFromTerm(Parse*, SrcList*, Token*, Token*, Token*,
1605                                       Select*, Expr*, IdList*);
1606 void sqlite3SrcListShiftJoinType(SrcList*);
1607 void sqlite3SrcListAssignCursors(Parse*, SrcList*);
1608 void sqlite3IdListDelete(IdList*);
1609 void sqlite3SrcListDelete(SrcList*);
1610 void sqlite3CreateIndex(Parse*,Token*,Token*,SrcList*,ExprList*,int,Token*,
1611                         Token*, int, int);
1612 void sqlite3DropIndex(Parse*, SrcList*, int);
1613 int sqlite3Select(Parse*, Select*, int, int, Select*, int, int*, char *aff);
1614 Select *sqlite3SelectNew(Parse*,ExprList*,SrcList*,Expr*,ExprList*,
1615                          Expr*,ExprList*,int,Expr*,Expr*);
1616 void sqlite3SelectDelete(Select*);
1617 Table *sqlite3SrcListLookup(Parse*, SrcList*);
1618 int sqlite3IsReadOnly(Parse*, Table*, int);
1619 void sqlite3OpenTable(Parse*, int iCur, int iDb, Table*, int);
1620 void sqlite3DeleteFrom(Parse*, SrcList*, Expr*);
1621 void sqlite3Update(Parse*, SrcList*, ExprList*, Expr*, int);
1622 WhereInfo *sqlite3WhereBegin(Parse*, SrcList*, Expr*, ExprList**);
1623 void sqlite3WhereEnd(WhereInfo*);
1624 void sqlite3ExprCodeGetColumn(Vdbe*, Table*, int, int);
1625 void sqlite3ExprCode(Parse*, Expr*);
1626 void sqlite3ExprCodeAndCache(Parse*, Expr*);
1627 int sqlite3ExprCodeExprList(Parse*, ExprList*);
1628 void sqlite3ExprIfTrue(Parse*, Expr*, int, int);
1629 void sqlite3ExprIfFalse(Parse*, Expr*, int, int);
1630 Table *sqlite3FindTable(sqlite3*,const char*, const char*);
1631 Table *sqlite3LocateTable(Parse*,const char*, const char*);
1632 Index *sqlite3FindIndex(sqlite3*,const char*, const char*);
1633 void sqlite3UnlinkAndDeleteTable(sqlite3*,int,const char*);
1634 void sqlite3UnlinkAndDeleteIndex(sqlite3*,int,const char*);
1635 void sqlite3Vacuum(Parse*);
1636 int sqlite3RunVacuum(char**, sqlite3*);
1637 char *sqlite3NameFromToken(sqlite3*, Token*);
1638 int sqlite3ExprCompare(Expr*, Expr*);
1639 int sqlite3ExprResolveNames(NameContext *, Expr *);
1640 int sqlite3ExprAnalyzeAggregates(NameContext*, Expr*);
1641 int sqlite3ExprAnalyzeAggList(NameContext*,ExprList*);
1642 Vdbe *sqlite3GetVdbe(Parse*);
1643 Expr *sqlite3CreateIdExpr(Parse *, const char*);
1644 void sqlite3Randomness(int, void*);
1645 void sqlite3RollbackAll(sqlite3*);
1646 void sqlite3CodeVerifySchema(Parse*, int);
1647 void sqlite3BeginTransaction(Parse*, int);
1648 void sqlite3CommitTransaction(Parse*);
1649 void sqlite3RollbackTransaction(Parse*);
1650 int sqlite3ExprIsConstant(Expr*);
1651 int sqlite3ExprIsConstantNotJoin(Expr*);
1652 int sqlite3ExprIsConstantOrFunction(Expr*);
1653 int sqlite3ExprIsInteger(Expr*, int*);
1654 int sqlite3IsRowid(const char*);
1655 void sqlite3GenerateRowDelete(sqlite3*, Vdbe*, Table*, int, int);
1656 void sqlite3GenerateRowIndexDelete(Vdbe*, Table*, int, char*);
1657 void sqlite3GenerateIndexKey(Vdbe*, Index*, int);
1658 void sqlite3GenerateConstraintChecks(Parse*,Table*,int,char*,int,int,int,int);
1659 void sqlite3CompleteInsertion(Parse*, Table*, int, char*, int, int, int, int);
1660 void sqlite3OpenTableAndIndices(Parse*, Table*, int, int);
1661 void sqlite3BeginWriteOperation(Parse*, int, int);
1662 Expr *sqlite3ExprDup(sqlite3*,Expr*);
1663 void sqlite3TokenCopy(sqlite3*,Token*, Token*);
1664 ExprList *sqlite3ExprListDup(sqlite3*,ExprList*);
1665 SrcList *sqlite3SrcListDup(sqlite3*,SrcList*);
1666 IdList *sqlite3IdListDup(sqlite3*,IdList*);
1667 Select *sqlite3SelectDup(sqlite3*,Select*);
1668 FuncDef *sqlite3FindFunction(sqlite3*,const char*,int,int,u8,int);
1669 void sqlite3RegisterBuiltinFunctions(sqlite3*);
1670 void sqlite3RegisterDateTimeFunctions(sqlite3*);
1671 int sqlite3SafetyOn(sqlite3*);
1672 int sqlite3SafetyOff(sqlite3*);
1673 int sqlite3SafetyCheck(sqlite3*);
1674 void sqlite3ChangeCookie(sqlite3*, Vdbe*, int);
1675 
1676 #ifndef SQLITE_OMIT_TRIGGER
1677   void sqlite3BeginTrigger(Parse*, Token*,Token*,int,int,IdList*,SrcList*,
1678                            Expr*,int, int);
1679   void sqlite3FinishTrigger(Parse*, TriggerStep*, Token*);
1680   void sqlite3DropTrigger(Parse*, SrcList*, int);
1681   void sqlite3DropTriggerPtr(Parse*, Trigger*);
1682   int sqlite3TriggersExist(Parse*, Table*, int, ExprList*);
1683   int sqlite3CodeRowTrigger(Parse*, int, ExprList*, int, Table *, int, int,
1684                            int, int);
1685   void sqliteViewTriggers(Parse*, Table*, Expr*, int, ExprList*);
1686   void sqlite3DeleteTriggerStep(TriggerStep*);
1687   TriggerStep *sqlite3TriggerSelectStep(sqlite3*,Select*);
1688   TriggerStep *sqlite3TriggerInsertStep(sqlite3*,Token*, IdList*,
1689                                         ExprList*,Select*,int);
1690   TriggerStep *sqlite3TriggerUpdateStep(sqlite3*,Token*,ExprList*, Expr*, int);
1691   TriggerStep *sqlite3TriggerDeleteStep(sqlite3*,Token*, Expr*);
1692   void sqlite3DeleteTrigger(Trigger*);
1693   void sqlite3UnlinkAndDeleteTrigger(sqlite3*,int,const char*);
1694 #else
1695 # define sqlite3TriggersExist(A,B,C,D,E,F) 0
1696 # define sqlite3DeleteTrigger(A)
1697 # define sqlite3DropTriggerPtr(A,B)
1698 # define sqlite3UnlinkAndDeleteTrigger(A,B,C)
1699 # define sqlite3CodeRowTrigger(A,B,C,D,E,F,G,H,I) 0
1700 #endif
1701 
1702 int sqlite3JoinType(Parse*, Token*, Token*, Token*);
1703 void sqlite3CreateForeignKey(Parse*, ExprList*, Token*, ExprList*, int);
1704 void sqlite3DeferForeignKey(Parse*, int);
1705 #ifndef SQLITE_OMIT_AUTHORIZATION
1706   void sqlite3AuthRead(Parse*,Expr*,SrcList*);
1707   int sqlite3AuthCheck(Parse*,int, const char*, const char*, const char*);
1708   void sqlite3AuthContextPush(Parse*, AuthContext*, const char*);
1709   void sqlite3AuthContextPop(AuthContext*);
1710 #else
1711 # define sqlite3AuthRead(a,b,c)
1712 # define sqlite3AuthCheck(a,b,c,d,e)    SQLITE_OK
1713 # define sqlite3AuthContextPush(a,b,c)
1714 # define sqlite3AuthContextPop(a)  ((void)(a))
1715 #endif
1716 void sqlite3Attach(Parse*, Expr*, Expr*, Expr*);
1717 void sqlite3Detach(Parse*, Expr*);
1718 int sqlite3BtreeFactory(const sqlite3 *db, const char *zFilename,
1719                        int omitJournal, int nCache, Btree **ppBtree);
1720 int sqlite3FixInit(DbFixer*, Parse*, int, const char*, const Token*);
1721 int sqlite3FixSrcList(DbFixer*, SrcList*);
1722 int sqlite3FixSelect(DbFixer*, Select*);
1723 int sqlite3FixExpr(DbFixer*, Expr*);
1724 int sqlite3FixExprList(DbFixer*, ExprList*);
1725 int sqlite3FixTriggerStep(DbFixer*, TriggerStep*);
1726 int sqlite3AtoF(const char *z, double*);
1727 char *sqlite3_snprintf(int,char*,const char*,...);
1728 int sqlite3GetInt32(const char *, int*);
1729 int sqlite3FitsIn64Bits(const char *);
1730 int sqlite3Utf16ByteLen(const void *pData, int nChar);
1731 int sqlite3Utf8CharLen(const char *pData, int nByte);
1732 int sqlite3Utf8Read(const u8*, const u8*, const u8**);
1733 int sqlite3PutVarint(unsigned char *, u64);
1734 int sqlite3GetVarint(const unsigned char *, u64 *);
1735 int sqlite3GetVarint32(const unsigned char *, u32 *);
1736 int sqlite3VarintLen(u64 v);
1737 void sqlite3IndexAffinityStr(Vdbe *, Index *);
1738 void sqlite3TableAffinityStr(Vdbe *, Table *);
1739 char sqlite3CompareAffinity(Expr *pExpr, char aff2);
1740 int sqlite3IndexAffinityOk(Expr *pExpr, char idx_affinity);
1741 char sqlite3ExprAffinity(Expr *pExpr);
1742 int sqlite3Atoi64(const char*, i64*);
1743 void sqlite3Error(sqlite3*, int, const char*,...);
1744 void *sqlite3HexToBlob(sqlite3*, const char *z);
1745 int sqlite3TwoPartName(Parse *, Token *, Token *, Token **);
1746 const char *sqlite3ErrStr(int);
1747 int sqlite3ReadSchema(Parse *pParse);
1748 CollSeq *sqlite3FindCollSeq(sqlite3*,u8 enc, const char *,int,int);
1749 CollSeq *sqlite3LocateCollSeq(Parse *pParse, const char *zName, int nName);
1750 CollSeq *sqlite3ExprCollSeq(Parse *pParse, Expr *pExpr);
1751 Expr *sqlite3ExprSetColl(Parse *pParse, Expr *, Token *);
1752 int sqlite3CheckCollSeq(Parse *, CollSeq *);
1753 int sqlite3CheckObjectName(Parse *, const char *);
1754 void sqlite3VdbeSetChanges(sqlite3 *, int);
1755 
1756 const void *sqlite3ValueText(sqlite3_value*, u8);
1757 int sqlite3ValueBytes(sqlite3_value*, u8);
1758 void sqlite3ValueSetStr(sqlite3_value*, int, const void *,u8,
1759                         void(*)(void*));
1760 void sqlite3ValueFree(sqlite3_value*);
1761 sqlite3_value *sqlite3ValueNew(sqlite3 *);
1762 char *sqlite3Utf16to8(sqlite3 *, const void*, int);
1763 int sqlite3ValueFromExpr(sqlite3 *, Expr *, u8, u8, sqlite3_value **);
1764 void sqlite3ValueApplyAffinity(sqlite3_value *, u8, u8);
1765 #ifndef SQLITE_AMALGAMATION
1766 extern const unsigned char sqlite3UpperToLower[];
1767 #endif
1768 void sqlite3RootPageMoved(Db*, int, int);
1769 void sqlite3Reindex(Parse*, Token*, Token*);
1770 void sqlite3AlterFunctions(sqlite3*);
1771 void sqlite3AlterRenameTable(Parse*, SrcList*, Token*);
1772 int sqlite3GetToken(const unsigned char *, int *);
1773 void sqlite3NestedParse(Parse*, const char*, ...);
1774 void sqlite3ExpirePreparedStatements(sqlite3*);
1775 void sqlite3CodeSubselect(Parse *, Expr *);
1776 int sqlite3SelectResolve(Parse *, Select *, NameContext *);
1777 void sqlite3ColumnDefault(Vdbe *, Table *, int);
1778 void sqlite3AlterFinishAddColumn(Parse *, Token *);
1779 void sqlite3AlterBeginAddColumn(Parse *, SrcList *);
1780 CollSeq *sqlite3GetCollSeq(sqlite3*, CollSeq *, const char *, int);
1781 char sqlite3AffinityType(const Token*);
1782 void sqlite3Analyze(Parse*, Token*, Token*);
1783 int sqlite3InvokeBusyHandler(BusyHandler*);
1784 int sqlite3FindDb(sqlite3*, Token*);
1785 int sqlite3AnalysisLoad(sqlite3*,int iDB);
1786 void sqlite3DefaultRowEst(Index*);
1787 void sqlite3RegisterLikeFunctions(sqlite3*, int);
1788 int sqlite3IsLikeFunction(sqlite3*,Expr*,int*,char*);
1789 void sqlite3AttachFunctions(sqlite3 *);
1790 void sqlite3MinimumFileFormat(Parse*, int, int);
1791 void sqlite3SchemaFree(void *);
1792 Schema *sqlite3SchemaGet(sqlite3 *, Btree *);
1793 int sqlite3SchemaToIndex(sqlite3 *db, Schema *);
1794 KeyInfo *sqlite3IndexKeyinfo(Parse *, Index *);
1795 int sqlite3CreateFunc(sqlite3 *, const char *, int, int, void *,
1796   void (*)(sqlite3_context*,int,sqlite3_value **),
1797   void (*)(sqlite3_context*,int,sqlite3_value **), void (*)(sqlite3_context*));
1798 int sqlite3ApiExit(sqlite3 *db, int);
1799 void sqlite3AbortOtherActiveVdbes(sqlite3 *, Vdbe *);
1800 int sqlite3OpenTempDatabase(Parse *);
1801 
1802 
1803 /*
1804 ** The interface to the LEMON-generated parser
1805 */
1806 void *sqlite3ParserAlloc(void*(*)(size_t));
1807 void sqlite3ParserFree(void*, void(*)(void*));
1808 void sqlite3Parser(void*, int, Token, Parse*);
1809 
1810 #ifndef SQLITE_OMIT_LOAD_EXTENSION
1811   void sqlite3CloseExtensions(sqlite3*);
1812   int sqlite3AutoLoadExtensions(sqlite3*);
1813 #else
1814 # define sqlite3CloseExtensions(X)
1815 # define sqlite3AutoLoadExtensions(X)  SQLITE_OK
1816 #endif
1817 
1818 #ifndef SQLITE_OMIT_SHARED_CACHE
1819   void sqlite3TableLock(Parse *, int, int, u8, const char *);
1820 #else
1821   #define sqlite3TableLock(v,w,x,y,z)
1822 #endif
1823 
1824 #ifdef SQLITE_TEST
1825   int sqlite3Utf8To8(unsigned char*);
1826 #endif
1827 
1828 /*
1829 ** The MallocDisallow() and MallocAllow() routines are like asserts.
1830 ** Call them around a section of code that you do not expect to do
1831 ** any memory allocation.
1832 */
1833 #ifdef SQLITE_MEMDEBUG
1834   void sqlite3MallocDisallow(void);
1835   void sqlite3MallocAllow(void);
1836   void sqlite3MallocBenignFailure(int);
1837 #else
1838 # define sqlite3MallocDisallow()
1839 # define sqlite3MallocAllow()
1840 # define sqlite3MallocBenignFailure(x)
1841 #endif
1842 
1843 
1844 #ifdef SQLITE_OMIT_VIRTUALTABLE
1845 #  define sqlite3VtabClear(X)
1846 #  define sqlite3VtabSync(X,Y) (Y)
1847 #  define sqlite3VtabRollback(X)
1848 #  define sqlite3VtabCommit(X)
1849 #else
1850    void sqlite3VtabClear(Table*);
1851    int sqlite3VtabSync(sqlite3 *db, int rc);
1852    int sqlite3VtabRollback(sqlite3 *db);
1853    int sqlite3VtabCommit(sqlite3 *db);
1854 #endif
1855 void sqlite3VtabLock(sqlite3_vtab*);
1856 void sqlite3VtabUnlock(sqlite3*, sqlite3_vtab*);
1857 void sqlite3VtabBeginParse(Parse*, Token*, Token*, Token*);
1858 void sqlite3VtabFinishParse(Parse*, Token*);
1859 void sqlite3VtabArgInit(Parse*);
1860 void sqlite3VtabArgExtend(Parse*, Token*);
1861 int sqlite3VtabCallCreate(sqlite3*, int, const char *, char **);
1862 int sqlite3VtabCallConnect(Parse*, Table*);
1863 int sqlite3VtabCallDestroy(sqlite3*, int, const char *);
1864 int sqlite3VtabBegin(sqlite3 *, sqlite3_vtab *);
1865 FuncDef *sqlite3VtabOverloadFunction(sqlite3 *,FuncDef*, int nArg, Expr*);
1866 void sqlite3InvalidFunction(sqlite3_context*,int,sqlite3_value**);
1867 int sqlite3Reprepare(Vdbe*);
1868 void sqlite3ExprListCheckLength(Parse*, ExprList*, int, const char*);
1869 CollSeq *sqlite3BinaryCompareCollSeq(Parse *, Expr *, Expr *);
1870 
1871 #ifdef SQLITE_ENABLE_ATOMIC_WRITE
1872   int sqlite3JournalOpen(sqlite3_vfs *, const char *, sqlite3_file *, int, int);
1873   int sqlite3JournalSize(sqlite3_vfs *);
1874   int sqlite3JournalCreate(sqlite3_file *);
1875 #else
1876   #define sqlite3JournalSize(pVfs) ((pVfs)->szOsFile)
1877 #endif
1878 
1879 #if SQLITE_MAX_EXPR_DEPTH>0
1880   void sqlite3ExprSetHeight(Expr *);
1881   int sqlite3SelectExprHeight(Select *);
1882 #else
1883   #define sqlite3ExprSetHeight(x)
1884 #endif
1885 
1886 u32 sqlite3Get4byte(const u8*);
1887 void sqlite3Put4byte(u8*, u32);
1888 
1889 #ifdef SQLITE_SSE
1890 #include "sseInt.h"
1891 #endif
1892 
1893 #ifdef SQLITE_DEBUG
1894   void sqlite3ParserTrace(FILE*, char *);
1895 #endif
1896 
1897 /*
1898 ** If the SQLITE_ENABLE IOTRACE exists then the global variable
1899 ** sqlite3_io_trace is a pointer to a printf-like routine used to
1900 ** print I/O tracing messages.
1901 */
1902 #ifdef SQLITE_ENABLE_IOTRACE
1903 # define IOTRACE(A)  if( sqlite3_io_trace ){ sqlite3_io_trace A; }
1904   void sqlite3VdbeIOTraceSql(Vdbe*);
1905 #else
1906 # define IOTRACE(A)
1907 # define sqlite3VdbeIOTraceSql(X)
1908 #endif
1909 SQLITE_EXTERN void (*sqlite3_io_trace)(const char*,...);
1910 
1911 #endif
1912