/ Check-in [f44b8bae]
Login

Many hyperlinks are disabled.
Use anonymous login to enable hyperlinks.

Overview
Comment:Add pzErr parameters to the xConnect and xCreate methods of virtual tables in order to provide better error reporting. This is an interface change for virtual tables. Prior virtual table implementations will need to be modified and recompiled. (CVS 3402)
Downloads: Tarball | ZIP archive | SQL archive
Timelines: family | ancestors | descendants | both | trunk
Files: files | file ages | folders
SHA1: f44b8bae97b6872524580009c96d07391578c388
User & Date: drh 2006-09-10 17:31:59
Context
2006-09-11
00:34
Add a rudimentary tokenizer and parser to FTS1 for parsing the module arguments during initialization. Recognized arguments include a tokenizer selector and a list of virtual table columns. (CVS 3403) check-in: 227dc3fe user: drh tags: trunk
2006-09-10
17:31
Add pzErr parameters to the xConnect and xCreate methods of virtual tables in order to provide better error reporting. This is an interface change for virtual tables. Prior virtual table implementations will need to be modified and recompiled. (CVS 3402) check-in: f44b8bae user: drh tags: trunk
17:08
Add a new zErrMsg field to the sqlite3_vtab structure to support returning error messages from virtual table constructors. This change means that virtual table implementations compiled as loadable extensions for version 3.3.7 will need to be recompile for version 3.3.8 and will not be usable by both versions at one. The virtual table mechanism is still considered experimental so we feel justified in breaking backwards compatibility in this way. Additional interface changes might occurs in the future. (CVS 3401) check-in: 36693a5c user: drh tags: trunk
Changes
Hide Diffs Unified Diffs Ignore Whitespace Patch

Changes to ext/fts1/fts1.c.

1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130

1131
1132
1133
1134
1135
1136
1137
....
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
....
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
** argv[0] - module name
** argv[1] - database name
** argv[2] - table name
** argv[3] - tokenizer name (optional, a sensible default is provided)
** argv[4..] - passed to tokenizer (optional based on tokenizer)
**/
static int fulltextConnect(sqlite3 *db, void *pAux, int argc, char **argv,
                           sqlite3_vtab **ppVTab){
  int rc;
  fulltext_vtab *v;
  const sqlite3_tokenizer_module *m = NULL;

  assert( argc>=3 );
  v = (fulltext_vtab *) malloc(sizeof(fulltext_vtab));
  /* sqlite will initialize v->base */
  v->db = db;
  v->zName = string_dup(argv[2]);
  v->pTokenizer = NULL;

  if( argc==3 ){
    sqlite3Fts1SimpleTokenizerModule(&m);
  } else {
    /* TODO(shess) For now, add new tokenizers as else if clauses. */
    if( !strcmp(argv[3], "simple") ){
      sqlite3Fts1SimpleTokenizerModule(&m);
    } else {

      assert( "unrecognized tokenizer"==NULL );
    }
  }

  /* TODO(shess) Since tokenization impacts the index, the parameters
  ** to the tokenizer need to be identical when a persistent virtual
  ** table is re-created.  One solution would be a meta-table to track
................................................................................

  *ppVTab = &v->base;
  TRACE(("FTS1 Connect %p\n", v));
  return SQLITE_OK;
}

static int fulltextCreate(sqlite3 *db, void *pAux, int argc, char **argv,
                          sqlite3_vtab **ppVTab){
  int rc;
  assert( argc>=3 );
  TRACE(("FTS1 Create\n"));

  /* The %_content table holds the text of each full-text item, with
  ** the rowid used as the docid.
  **
................................................................................
  */
  rc = sql_exec(db, argv[2],
    "create table %_content(content text);"
    "create table %_term(term text, segment integer, doclist blob, "
                        "primary key(term, segment));");
  if( rc!=SQLITE_OK ) return rc;

  return fulltextConnect(db, pAux, argc, argv, ppVTab);
}

/* Decide how to handle an SQL query.
 * At the moment, MATCH queries can include implicit boolean ANDs; we
 * haven't implemented phrase searches or OR yet. */
static int fulltextBestIndex(sqlite3_vtab *pVTab, sqlite3_index_info *pInfo){
  int i;







|






|











>







 







|







 







|







1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
....
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
....
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
** argv[0] - module name
** argv[1] - database name
** argv[2] - table name
** argv[3] - tokenizer name (optional, a sensible default is provided)
** argv[4..] - passed to tokenizer (optional based on tokenizer)
**/
static int fulltextConnect(sqlite3 *db, void *pAux, int argc, char **argv,
                           sqlite3_vtab **ppVTab, char **pzErr){
  int rc;
  fulltext_vtab *v;
  const sqlite3_tokenizer_module *m = NULL;

  assert( argc>=3 );
  v = (fulltext_vtab *) malloc(sizeof(fulltext_vtab));
  memset(v, 0, sizeof(*v));
  v->db = db;
  v->zName = string_dup(argv[2]);
  v->pTokenizer = NULL;

  if( argc==3 ){
    sqlite3Fts1SimpleTokenizerModule(&m);
  } else {
    /* TODO(shess) For now, add new tokenizers as else if clauses. */
    if( !strcmp(argv[3], "simple") ){
      sqlite3Fts1SimpleTokenizerModule(&m);
    } else {
      *pzErr = sqlite3_mprintf("unknown tokenizer: %s", argv[3]);
      assert( "unrecognized tokenizer"==NULL );
    }
  }

  /* TODO(shess) Since tokenization impacts the index, the parameters
  ** to the tokenizer need to be identical when a persistent virtual
  ** table is re-created.  One solution would be a meta-table to track
................................................................................

  *ppVTab = &v->base;
  TRACE(("FTS1 Connect %p\n", v));
  return SQLITE_OK;
}

static int fulltextCreate(sqlite3 *db, void *pAux, int argc, char **argv,
                          sqlite3_vtab **ppVTab, char **pzErr){
  int rc;
  assert( argc>=3 );
  TRACE(("FTS1 Create\n"));

  /* The %_content table holds the text of each full-text item, with
  ** the rowid used as the docid.
  **
................................................................................
  */
  rc = sql_exec(db, argv[2],
    "create table %_content(content text);"
    "create table %_term(term text, segment integer, doclist blob, "
                        "primary key(term, segment));");
  if( rc!=SQLITE_OK ) return rc;

  return fulltextConnect(db, pAux, argc, argv, ppVTab, pzErr);
}

/* Decide how to handle an SQL query.
 * At the moment, MATCH queries can include implicit boolean ANDs; we
 * haven't implemented phrase searches or OR yet. */
static int fulltextBestIndex(sqlite3_vtab *pVTab, sqlite3_index_info *pInfo){
  int i;

Changes to src/sqlite.h.in.

8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
....
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
....
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This header file defines the interface that the SQLite library
** presents to client programs.
**
** @(#) $Id: sqlite.h.in,v 1.190 2006/09/10 17:08:30 drh Exp $
*/
#ifndef _SQLITE3_H_
#define _SQLITE3_H_
#include <stdarg.h>     /* Needed for the definition of va_list */

/*
** Make sure we can call this stuff from C++.
................................................................................
** by an instance of the following structure.  This structure consists
** mostly of methods for the module.
*/
struct sqlite3_module {
  int iVersion;
  int (*xCreate)(sqlite3*, void *pAux,
               int argc, char **argv,
               sqlite3_vtab **ppVTab);
  int (*xConnect)(sqlite3*, void *pAux,
               int argc, char **argv,
               sqlite3_vtab **ppVTab);
  int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*);
  int (*xDisconnect)(sqlite3_vtab *pVTab);
  int (*xDestroy)(sqlite3_vtab *pVTab);
  int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor);
  int (*xClose)(sqlite3_vtab_cursor*);
  int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr,
                int argc, sqlite3_value **argv);
................................................................................
** that sqlite3_mprintf() and sqlite3_free() are used on the zErrMsg field
** since virtual tables are commonly implemented in loadable extensions which
** do not have access to sqlite3MPrintf() or sqlite3Free().
*/
struct sqlite3_vtab {
  const sqlite3_module *pModule;  /* The module for this virtual table */
  int nRef;                       /* Used internally */
  char *zErrMsg;                  /* Error message text */
  /* Virtual table implementations will typically add additional fields */
};

/* Every module implementation uses a subclass of the following structure
** to describe cursors that point into the virtual table and are used
** to loop through the virtual table.  Cursors are created using the
** xOpen method of the module.  Each module implementation will define







|







 







|


|







 







|







8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
....
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
....
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This header file defines the interface that the SQLite library
** presents to client programs.
**
** @(#) $Id: sqlite.h.in,v 1.191 2006/09/10 17:31:59 drh Exp $
*/
#ifndef _SQLITE3_H_
#define _SQLITE3_H_
#include <stdarg.h>     /* Needed for the definition of va_list */

/*
** Make sure we can call this stuff from C++.
................................................................................
** by an instance of the following structure.  This structure consists
** mostly of methods for the module.
*/
struct sqlite3_module {
  int iVersion;
  int (*xCreate)(sqlite3*, void *pAux,
               int argc, char **argv,
               sqlite3_vtab **ppVTab, char**);
  int (*xConnect)(sqlite3*, void *pAux,
               int argc, char **argv,
               sqlite3_vtab **ppVTab, char**);
  int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*);
  int (*xDisconnect)(sqlite3_vtab *pVTab);
  int (*xDestroy)(sqlite3_vtab *pVTab);
  int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor);
  int (*xClose)(sqlite3_vtab_cursor*);
  int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr,
                int argc, sqlite3_value **argv);
................................................................................
** that sqlite3_mprintf() and sqlite3_free() are used on the zErrMsg field
** since virtual tables are commonly implemented in loadable extensions which
** do not have access to sqlite3MPrintf() or sqlite3Free().
*/
struct sqlite3_vtab {
  const sqlite3_module *pModule;  /* The module for this virtual table */
  int nRef;                       /* Used internally */
  char *zErrMsg;                  /* Error message from sqlite3_mprintf() */
  /* Virtual table implementations will typically add additional fields */
};

/* Every module implementation uses a subclass of the following structure
** to describe cursors that point into the virtual table and are used
** to loop through the virtual table.  Cursors are created using the
** xOpen method of the module.  Each module implementation will define

Changes to src/test8.c.

9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
...
308
309
310
311
312
313
314
315

316
317
318
319
320
321
322
...
354
355
356
357
358
359
360
361

362
363
364
365
366
367
368
369
370
371
372
...
389
390
391
392
393
394
395
396

397
398
399
400
401
402
403
404
405
406
**    May you share freely, never taking more than you give.
**
*************************************************************************
** Code for testing the virtual table interfaces.  This code
** is not included in the SQLite library.  It is used for automated
** testing of the SQLite library.
**
** $Id: test8.c,v 1.40 2006/07/08 18:09:15 drh Exp $
*/
#include "sqliteInt.h"
#include "tcl.h"
#include "os.h"
#include <stdlib.h>
#include <string.h>

................................................................................
** to allocate the required in-memory structures for a newly connected
** virtual table.
*/
static int echoConstructor(
  sqlite3 *db,
  void *pAux,
  int argc, char **argv,
  sqlite3_vtab **ppVtab

){
  int i;
  echo_vtab *pVtab;

  /* Allocate the sqlite3_vtab/echo_vtab structure itself */
  pVtab = sqliteMalloc( sizeof(*pVtab) );
  if( !pVtab ){
................................................................................
/* 
** Echo virtual table module xCreate method.
*/
static int echoCreate(
  sqlite3 *db,
  void *pAux,
  int argc, char **argv,
  sqlite3_vtab **ppVtab

){
  int rc = SQLITE_OK;
  appendToEchoModule((Tcl_Interp *)(pAux), "xCreate");
  rc = echoConstructor(db, pAux, argc, argv, ppVtab);

  /* If there were two arguments passed to the module at the SQL level 
  ** (i.e. "CREATE VIRTUAL TABLE tbl USING echo(arg1, arg2)"), then 
  ** the second argument is used as a table name. Attempt to create
  ** such a table with a single column, "logmsg". This table will
  ** be used to log calls to the xUpdate method. It will be deleted
  ** when the virtual table is DROPed.
................................................................................
/* 
** Echo virtual table module xConnect method.
*/
static int echoConnect(
  sqlite3 *db,
  void *pAux,
  int argc, char **argv,
  sqlite3_vtab **ppVtab

){
  appendToEchoModule((Tcl_Interp *)(pAux), "xConnect");
  return echoConstructor(db, pAux, argc, argv, ppVtab);
}

/* 
** Echo virtual table module xDisconnect method.
*/
static int echoDisconnect(sqlite3_vtab *pVtab){
  appendToEchoModule(((echo_vtab *)pVtab)->interp, "xDisconnect");







|







 







|
>







 







|
>



|







 







|
>


|







9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
...
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
...
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
...
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
**    May you share freely, never taking more than you give.
**
*************************************************************************
** Code for testing the virtual table interfaces.  This code
** is not included in the SQLite library.  It is used for automated
** testing of the SQLite library.
**
** $Id: test8.c,v 1.41 2006/09/10 17:32:00 drh Exp $
*/
#include "sqliteInt.h"
#include "tcl.h"
#include "os.h"
#include <stdlib.h>
#include <string.h>

................................................................................
** to allocate the required in-memory structures for a newly connected
** virtual table.
*/
static int echoConstructor(
  sqlite3 *db,
  void *pAux,
  int argc, char **argv,
  sqlite3_vtab **ppVtab,
  char **pzErr
){
  int i;
  echo_vtab *pVtab;

  /* Allocate the sqlite3_vtab/echo_vtab structure itself */
  pVtab = sqliteMalloc( sizeof(*pVtab) );
  if( !pVtab ){
................................................................................
/* 
** Echo virtual table module xCreate method.
*/
static int echoCreate(
  sqlite3 *db,
  void *pAux,
  int argc, char **argv,
  sqlite3_vtab **ppVtab,
  char **pzErr
){
  int rc = SQLITE_OK;
  appendToEchoModule((Tcl_Interp *)(pAux), "xCreate");
  rc = echoConstructor(db, pAux, argc, argv, ppVtab, pzErr);

  /* If there were two arguments passed to the module at the SQL level 
  ** (i.e. "CREATE VIRTUAL TABLE tbl USING echo(arg1, arg2)"), then 
  ** the second argument is used as a table name. Attempt to create
  ** such a table with a single column, "logmsg". This table will
  ** be used to log calls to the xUpdate method. It will be deleted
  ** when the virtual table is DROPed.
................................................................................
/* 
** Echo virtual table module xConnect method.
*/
static int echoConnect(
  sqlite3 *db,
  void *pAux,
  int argc, char **argv,
  sqlite3_vtab **ppVtab,
  char **pzErr
){
  appendToEchoModule((Tcl_Interp *)(pAux), "xConnect");
  return echoConstructor(db, pAux, argc, argv, ppVtab, pzErr);
}

/* 
** Echo virtual table module xDisconnect method.
*/
static int echoDisconnect(sqlite3_vtab *pVtab){
  appendToEchoModule(((echo_vtab *)pVtab)->interp, "xDisconnect");

Changes to src/test_schema.c.

9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
..
81
82
83
84
85
86
87
88

89
90
91
92
93
94
95
**    May you share freely, never taking more than you give.
**
*************************************************************************
** Code for testing the virtual table interfaces.  This code
** is not included in the SQLite library.  It is used for automated
** testing of the SQLite library.
**
** $Id: test_schema.c,v 1.9 2006/07/08 17:06:44 drh Exp $
*/

/* The code in this file defines a sqlite3 virtual-table module that
** provides a read-only view of the current database schema. There is one
** row in the schema table for each column in the database schema.
*/
#define SCHEMA \
................................................................................
/*
** Table constructor for the schema module.
*/
static int schemaCreate(
  sqlite3 *db,
  void *pAux,
  int argc, char **argv,
  sqlite3_vtab **ppVtab

){
  int rc = SQLITE_NOMEM;
  schema_vtab *pVtab = MALLOC(sizeof(schema_vtab));
  if( pVtab ){
    memset(pVtab, 0, sizeof(schema_vtab));
    pVtab->db = db;
#ifndef SQLITE_OMIT_VIRTUALTABLE







|







 







|
>







9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
..
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
**    May you share freely, never taking more than you give.
**
*************************************************************************
** Code for testing the virtual table interfaces.  This code
** is not included in the SQLite library.  It is used for automated
** testing of the SQLite library.
**
** $Id: test_schema.c,v 1.10 2006/09/10 17:32:00 drh Exp $
*/

/* The code in this file defines a sqlite3 virtual-table module that
** provides a read-only view of the current database schema. There is one
** row in the schema table for each column in the database schema.
*/
#define SCHEMA \
................................................................................
/*
** Table constructor for the schema module.
*/
static int schemaCreate(
  sqlite3 *db,
  void *pAux,
  int argc, char **argv,
  sqlite3_vtab **ppVtab,
  char **pzErr
){
  int rc = SQLITE_NOMEM;
  schema_vtab *pVtab = MALLOC(sizeof(schema_vtab));
  if( pVtab ){
    memset(pVtab, 0, sizeof(schema_vtab));
    pVtab->db = db;
#ifndef SQLITE_OMIT_VIRTUALTABLE

Changes to src/test_tclvar.c.

12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
..
48
49
50
51
52
53
54
55

56
57
58
59
60
61
62
** Code for testing the virtual table interfaces.  This code
** is not included in the SQLite library.  It is used for automated
** testing of the SQLite library.
**
** The emphasis of this file is a virtual table that provides
** access to TCL variables.
**
** $Id: test_tclvar.c,v 1.8 2006/08/15 14:21:16 drh Exp $
*/
#include "sqliteInt.h"
#include "tcl.h"
#include "os.h"
#include <stdlib.h>
#include <string.h>

................................................................................
};

/* Methods for the tclvar module */
static int tclvarConnect(
  sqlite3 *db,
  void *pAux,
  int argc, char **argv,
  sqlite3_vtab **ppVtab

){
  tclvar_vtab *pVtab;
  static const char zSchema[] = 
     "CREATE TABLE whatever(name TEXT, arrayname TEXT, value TEXT)";
  pVtab = sqliteMalloc( sizeof(*pVtab) );
  if( pVtab==0 ) return SQLITE_NOMEM;
  *ppVtab = &pVtab->base;







|







 







|
>







12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
..
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
** Code for testing the virtual table interfaces.  This code
** is not included in the SQLite library.  It is used for automated
** testing of the SQLite library.
**
** The emphasis of this file is a virtual table that provides
** access to TCL variables.
**
** $Id: test_tclvar.c,v 1.9 2006/09/10 17:32:00 drh Exp $
*/
#include "sqliteInt.h"
#include "tcl.h"
#include "os.h"
#include <stdlib.h>
#include <string.h>

................................................................................
};

/* Methods for the tclvar module */
static int tclvarConnect(
  sqlite3 *db,
  void *pAux,
  int argc, char **argv,
  sqlite3_vtab **ppVtab,
  char **pzErr
){
  tclvar_vtab *pVtab;
  static const char zSchema[] = 
     "CREATE TABLE whatever(name TEXT, arrayname TEXT, value TEXT)";
  pVtab = sqliteMalloc( sizeof(*pVtab) );
  if( pVtab==0 ) return SQLITE_NOMEM;
  *ppVtab = &pVtab->base;

Changes to src/vtab.c.

7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
..
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
...
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains code used to help implement virtual tables.
**
** $Id: vtab.c,v 1.32 2006/09/10 17:08:30 drh Exp $
*/
#ifndef SQLITE_OMIT_VIRTUALTABLE
#include "sqliteInt.h"

/*
** External API function used to create a new virtual-table module.
*/
................................................................................
/*
** Unlock a virtual table.  When the last lock is removed,
** disconnect the virtual table.
*/
void sqlite3VtabUnlock(sqlite3_vtab *pVtab){
  pVtab->nRef--;
  if( pVtab->nRef==0 ){
    sqlite3_free(pVtab->zErrMsg);
    pVtab->zErrMsg = 0;
    pVtab->pModule->xDisconnect(pVtab);
  }
}

/*
** Clear any and all virtual-table information from the Table record.
** This routine is called, for example, just before deleting the Table
................................................................................
** pointer to the function to invoke is passed as the fourth parameter
** to this procedure.
*/
static int vtabCallConstructor(
  sqlite3 *db, 
  Table *pTab,
  Module *pMod,
  int (*xConstruct)(sqlite3*, void *, int, char **, sqlite3_vtab **),
  char **pzErr
){
  int rc;
  int rc2;
  sqlite3_vtab *pVtab;
  char **azArg = pTab->azModuleArg;
  int nArg = pTab->nModuleArg;
  char *zErr = sqlite3MPrintf("vtable constructor failed: %s", pTab->zName);

  assert( !db->pVTab );
  assert( xConstruct );

  db->pVTab = pTab;
  rc = sqlite3SafetyOff(db);
  assert( rc==SQLITE_OK );
  rc = xConstruct(db, pMod->pAux, nArg, azArg, &pTab->pVtab);
  rc2 = sqlite3SafetyOn(db);
  pVtab = pTab->pVtab;
  if( rc==SQLITE_OK && pVtab ){
    pVtab->pModule = pMod->pModule;
    pVtab->nRef = 1;
  }

  if( SQLITE_OK!=rc ){
    if( pVtab && pVtab->zErrMsg ){
      *pzErr = sqlite3MPrintf("%s", pVtab->zErrMsg);
      sqlite3_free(pVtab->zErrMsg);
      pVtab->zErrMsg = 0;
    }else{
      *pzErr = zErr;
      zErr = 0;
    }
  }else if( db->pVTab ){
    const char *zFormat = "vtable constructor did not declare schema: %s";
    *pzErr = sqlite3MPrintf(zFormat, pTab->zName);
    rc = SQLITE_ERROR;
  } 
  if( rc==SQLITE_OK ){
    rc = rc2;
  }
  db->pVTab = 0;
  sqliteFree(zErr);
  return rc;
}

/*
** This function is invoked by the parser to call the xConnect() method
** of the virtual table pTab. If an error occurs, an error code is returned 
** and an error left in pParse.







|







 







<
<







 







|







|







|








|
|
|
|
|
<
<










<







7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
..
55
56
57
58
59
60
61


62
63
64
65
66
67
68
...
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318


319
320
321
322
323
324
325
326
327
328

329
330
331
332
333
334
335
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains code used to help implement virtual tables.
**
** $Id: vtab.c,v 1.33 2006/09/10 17:32:00 drh Exp $
*/
#ifndef SQLITE_OMIT_VIRTUALTABLE
#include "sqliteInt.h"

/*
** External API function used to create a new virtual-table module.
*/
................................................................................
/*
** Unlock a virtual table.  When the last lock is removed,
** disconnect the virtual table.
*/
void sqlite3VtabUnlock(sqlite3_vtab *pVtab){
  pVtab->nRef--;
  if( pVtab->nRef==0 ){


    pVtab->pModule->xDisconnect(pVtab);
  }
}

/*
** Clear any and all virtual-table information from the Table record.
** This routine is called, for example, just before deleting the Table
................................................................................
** pointer to the function to invoke is passed as the fourth parameter
** to this procedure.
*/
static int vtabCallConstructor(
  sqlite3 *db, 
  Table *pTab,
  Module *pMod,
  int (*xConstruct)(sqlite3*,void*,int,char**,sqlite3_vtab**,char**),
  char **pzErr
){
  int rc;
  int rc2;
  sqlite3_vtab *pVtab;
  char **azArg = pTab->azModuleArg;
  int nArg = pTab->nModuleArg;
  char *zErr = 0;

  assert( !db->pVTab );
  assert( xConstruct );

  db->pVTab = pTab;
  rc = sqlite3SafetyOff(db);
  assert( rc==SQLITE_OK );
  rc = xConstruct(db, pMod->pAux, nArg, azArg, &pTab->pVtab, &zErr);
  rc2 = sqlite3SafetyOn(db);
  pVtab = pTab->pVtab;
  if( rc==SQLITE_OK && pVtab ){
    pVtab->pModule = pMod->pModule;
    pVtab->nRef = 1;
  }

  if( SQLITE_OK!=rc ){
    if( zErr==0 ){
      *pzErr = sqlite3MPrintf("vtable constructor failed: %s", pTab->zName);
    }else {
      *pzErr = sqlite3_mprintf("%s", zErr);
      sqlite3_free(zErr);


    }
  }else if( db->pVTab ){
    const char *zFormat = "vtable constructor did not declare schema: %s";
    *pzErr = sqlite3MPrintf(zFormat, pTab->zName);
    rc = SQLITE_ERROR;
  } 
  if( rc==SQLITE_OK ){
    rc = rc2;
  }
  db->pVTab = 0;

  return rc;
}

/*
** This function is invoked by the parser to call the xConnect() method
** of the virtual table pTab. If an error occurs, an error code is returned 
** and an error left in pParse.