** 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;

** 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;

**    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

**    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

**    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");

**    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");

**    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

**    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

** 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;

** 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;

**    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.

**    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.