**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** in order to generate code for DELETE FROM statements.
**
** $Id: delete.c,v 1.124 2006/06/14 19:00:21 drh Exp $
*/
#include "sqliteInt.h"

/*
** Look up every table that is named in pSrc.  If any table is not found,
** add an error message to pParse->zErrMsg and return NULL.  If all tables
** are found, return a pointer to the last table.
................................................................................
** writable, generate an error message and return 1.  If it is
** writable return 0;
*/
int sqlite3IsReadOnly(Parse *pParse, Table *pTab, int viewOk){
  if( (pTab->readOnly && (pParse->db->flags & SQLITE_WriteSchema)==0
        && pParse->nested==0) 
#ifndef SQLITE_OMIT_VIRTUALTABLE
      || (pTab->pModule && pTab->pModule->xUpdate==0)
#endif
  ){
    sqlite3ErrorMsg(pParse, "table %s may not be modified", pTab->zName);
    return 1;
  }
#ifndef SQLITE_OMIT_VIEW
  if( !viewOk && pTab->pSelect ){

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** in order to generate code for DELETE FROM statements.
**
** $Id: delete.c,v 1.125 2006/06/15 04:28:13 danielk1977 Exp $
*/
#include "sqliteInt.h"

/*
** Look up every table that is named in pSrc.  If any table is not found,
** add an error message to pParse->zErrMsg and return NULL.  If all tables
** are found, return a pointer to the last table.
................................................................................
** writable, generate an error message and return 1.  If it is
** writable return 0;
*/
int sqlite3IsReadOnly(Parse *pParse, Table *pTab, int viewOk){
  if( (pTab->readOnly && (pParse->db->flags & SQLITE_WriteSchema)==0
        && pParse->nested==0) 
#ifndef SQLITE_OMIT_VIRTUALTABLE
      || (pTab->pMod && pTab->pMod->pModule->xUpdate==0)
#endif
  ){
    sqlite3ErrorMsg(pParse, "table %s may not be modified", pTab->zName);
    return 1;
  }
#ifndef SQLITE_OMIT_VIEW
  if( !viewOk && pTab->pSelect ){

**
*************************************************************************
** Main file for the SQLite library.  The routines in this file
** implement the programmer interface to the library.  Routines in
** other files are for internal use by SQLite and should not be
** accessed by users of the library.
**
** $Id: main.c,v 1.343 2006/06/14 15:35:37 drh Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>

/*
** The following constant value is used by the SQLITE_BIGENDIAN and
................................................................................

  for(i=sqliteHashFirst(&db->aCollSeq); i; i=sqliteHashNext(i)){
    CollSeq *pColl = (CollSeq *)sqliteHashData(i);
    sqliteFree(pColl);
  }
  sqlite3HashClear(&db->aCollSeq);
#ifndef SQLITE_OMIT_VIRTUALTABLE




  sqlite3HashClear(&db->aModule);
#endif

  sqlite3HashClear(&db->aFunc);
  sqlite3Error(db, SQLITE_OK, 0); /* Deallocates any cached error strings. */
  if( db->pErr ){
    sqlite3ValueFree(db->pErr);

**
*************************************************************************
** Main file for the SQLite library.  The routines in this file
** implement the programmer interface to the library.  Routines in
** other files are for internal use by SQLite and should not be
** accessed by users of the library.
**
** $Id: main.c,v 1.344 2006/06/15 04:28:13 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>

/*
** The following constant value is used by the SQLITE_BIGENDIAN and
................................................................................

  for(i=sqliteHashFirst(&db->aCollSeq); i; i=sqliteHashNext(i)){
    CollSeq *pColl = (CollSeq *)sqliteHashData(i);
    sqliteFree(pColl);
  }
  sqlite3HashClear(&db->aCollSeq);
#ifndef SQLITE_OMIT_VIRTUALTABLE
  for(i=sqliteHashFirst(&db->aModule); i; i=sqliteHashNext(i)){
    Module *pMod = (Module *)sqliteHashData(i);
    sqliteFree(pMod);
  }
  sqlite3HashClear(&db->aModule);
#endif

  sqlite3HashClear(&db->aFunc);
  sqlite3Error(db, SQLITE_OK, 0); /* Deallocates any cached error strings. */
  if( db->pErr ){
    sqlite3ValueFree(db->pErr);

**    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 1.176 2006/06/14 13:03:23 danielk1977 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++.
................................................................................
** A module is a class of virtual tables.  Each module is defined
** by an instance of the following structure.  This structure consists
** mostly of methods for the module.
*/
struct sqlite3_module {
  int iVersion;
  const char *zName;
  void *pAux;
  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*);
................................................................................
** connection.  Module names must be registered before creating new
** virtual tables on the module, or before using preexisting virtual
** tables of the module.
*/
int sqlite3_create_module(
  sqlite3 *db,               /* SQLite connection to register module with */
  const char *zName,         /* Name of the module */
  const sqlite3_module *     /* Methods for the module */

);

/*
** Every module implementation uses a subclass of the following structure
** to describe a particular instance of the module.  Each subclass will
** be taylored to the specific needs of the module implementation.   The
** purpose of this superclass is to define certain fields that are common

**    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 1.177 2006/06/15 04:28:13 danielk1977 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++.
................................................................................
** A module is a class of virtual tables.  Each module is defined
** by an instance of the following structure.  This structure consists
** mostly of methods for the module.
*/
struct sqlite3_module {
  int iVersion;
  const char *zName;

  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*);
................................................................................
** connection.  Module names must be registered before creating new
** virtual tables on the module, or before using preexisting virtual
** tables of the module.
*/
int sqlite3_create_module(
  sqlite3 *db,               /* SQLite connection to register module with */
  const char *zName,         /* Name of the module */
  const sqlite3_module *,    /* Methods for the module */
  void *                     /* Client data for xCreate/xConnect */
);

/*
** Every module implementation uses a subclass of the following structure
** to describe a particular instance of the module.  Each subclass will
** be taylored to the specific needs of the module implementation.   The
** purpose of this superclass is to define certain fields that are common

**    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.
**
*************************************************************************
** Internal interface definitions for SQLite.
**
** @(#) $Id: sqliteInt.h,v 1.505 2006/06/14 19:00:21 drh Exp $
*/
#ifndef _SQLITEINT_H_
#define _SQLITEINT_H_

/*
** Extra interface definitions for those who need them
*/
................................................................................
typedef struct ExprList ExprList;
typedef struct FKey FKey;
typedef struct FuncDef FuncDef;
typedef struct IdList IdList;
typedef struct Index Index;
typedef struct KeyClass KeyClass;
typedef struct KeyInfo KeyInfo;

typedef struct NameContext NameContext;
typedef struct Parse Parse;
typedef struct Select Select;
typedef struct SrcList SrcList;
typedef struct ThreadData ThreadData;
typedef struct Table Table;
typedef struct TableLock TableLock;
................................................................................
  FuncDef *pNext;      /* Next function with same name */
  void (*xFunc)(sqlite3_context*,int,sqlite3_value**); /* Regular function */
  void (*xStep)(sqlite3_context*,int,sqlite3_value**); /* Aggregate step */
  void (*xFinalize)(sqlite3_context*);                /* Aggregate finializer */
  char zName[1];       /* SQL name of the function.  MUST BE LAST */
};












/*
** Possible values for FuncDef.flags
*/
#define SQLITE_FUNC_LIKE   0x01  /* Candidate for the LIKE optimization */
#define SQLITE_FUNC_CASE   0x02  /* Case-sensitive LIKE-type function */

/*
................................................................................
#ifndef SQLITE_OMIT_CHECK
  Expr *pCheck;      /* The AND of all CHECK constraints */
#endif
#ifndef SQLITE_OMIT_ALTERTABLE
  int addColOffset;  /* Offset in CREATE TABLE statement to add a new column */
#endif
#ifndef SQLITE_OMIT_VIRTUALTABLE
  sqlite3_module *pModule;  /* Pointer to the implementation of the module */
  sqlite3_vtab *pVtab;      /* Pointer to the module instance */
  u8 isVirtual;             /* True if this is a virtual table */
  int nModuleArg;           /* Number of arguments to the module */
  char **azModuleArg;       /* Text of all module args. [0] is module name */
#endif
  Schema *pSchema;
};

**    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.
**
*************************************************************************
** Internal interface definitions for SQLite.
**
** @(#) $Id: sqliteInt.h,v 1.506 2006/06/15 04:28:13 danielk1977 Exp $
*/
#ifndef _SQLITEINT_H_
#define _SQLITEINT_H_

/*
** Extra interface definitions for those who need them
*/
................................................................................
typedef struct ExprList ExprList;
typedef struct FKey FKey;
typedef struct FuncDef FuncDef;
typedef struct IdList IdList;
typedef struct Index Index;
typedef struct KeyClass KeyClass;
typedef struct KeyInfo KeyInfo;
typedef struct Module Module;
typedef struct NameContext NameContext;
typedef struct Parse Parse;
typedef struct Select Select;
typedef struct SrcList SrcList;
typedef struct ThreadData ThreadData;
typedef struct Table Table;
typedef struct TableLock TableLock;
................................................................................
  FuncDef *pNext;      /* Next function with same name */
  void (*xFunc)(sqlite3_context*,int,sqlite3_value**); /* Regular function */
  void (*xStep)(sqlite3_context*,int,sqlite3_value**); /* Aggregate step */
  void (*xFinalize)(sqlite3_context*);                /* Aggregate finializer */
  char zName[1];       /* SQL name of the function.  MUST BE LAST */
};

/*
** Each SQLite module (virtual table definition) is defined by an
** instance of the following structure, stored in the sqlite3.aModule
** hash table.
*/
struct Module {
  const sqlite3_module *pModule;       /* Callback pointers */
  const char *zName;                   /* Name passed to create_module() */
  void *pAux;                          /* pAux passed to create_module() */
};

/*
** Possible values for FuncDef.flags
*/
#define SQLITE_FUNC_LIKE   0x01  /* Candidate for the LIKE optimization */
#define SQLITE_FUNC_CASE   0x02  /* Case-sensitive LIKE-type function */

/*
................................................................................
#ifndef SQLITE_OMIT_CHECK
  Expr *pCheck;      /* The AND of all CHECK constraints */
#endif
#ifndef SQLITE_OMIT_ALTERTABLE
  int addColOffset;  /* Offset in CREATE TABLE statement to add a new column */
#endif
#ifndef SQLITE_OMIT_VIRTUALTABLE
  Module *pMod;             /* Pointer to the implementation of the module */
  sqlite3_vtab *pVtab;      /* Pointer to the module instance */
  u8 isVirtual;             /* True if this is a virtual table */
  int nModuleArg;           /* Number of arguments to the module */
  char **azModuleArg;       /* Text of all module args. [0] is module name */
#endif
  Schema *pSchema;
};

**    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 1.19 2006/06/14 23:43:31 drh Exp $
*/
#include "sqliteInt.h"
#include "tcl.h"
#include "os.h"
#include <stdlib.h>
#include <string.h>

................................................................................
/*
** A virtual table module that merely echos method calls into TCL
** variables.
*/
static sqlite3_module echoModule = {
  0,                         /* iVersion */
  "echo",                    /* zName */
  0,                         /* pAux */
  echoCreate,
  echoConnect,
  echoBestIndex,
  echoDisconnect, 
  echoDestroy,
  echoOpen,                  /* xOpen - open a cursor */
  echoClose,                 /* xClose - close a cursor */
................................................................................
){
  sqlite3 *db;
  if( objc!=2 ){
    Tcl_WrongNumArgs(interp, 1, objv, "DB");
    return TCL_ERROR;
  }
  if( getDbPointer(interp, Tcl_GetString(objv[1]), &db) ) return TCL_ERROR;
  echoModule.pAux = interp;
#ifndef SQLITE_OMIT_VIRTUALTABLE
  sqlite3_create_module(db, "echo", &echoModule);
#endif
  return TCL_OK;
}


/*
** Register commands with the TCL interpreter.

**    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 1.20 2006/06/15 04:28:13 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include "tcl.h"
#include "os.h"
#include <stdlib.h>
#include <string.h>

................................................................................
/*
** A virtual table module that merely echos method calls into TCL
** variables.
*/
static sqlite3_module echoModule = {
  0,                         /* iVersion */
  "echo",                    /* zName */

  echoCreate,
  echoConnect,
  echoBestIndex,
  echoDisconnect, 
  echoDestroy,
  echoOpen,                  /* xOpen - open a cursor */
  echoClose,                 /* xClose - close a cursor */
................................................................................
){
  sqlite3 *db;
  if( objc!=2 ){
    Tcl_WrongNumArgs(interp, 1, objv, "DB");
    return TCL_ERROR;
  }
  if( getDbPointer(interp, Tcl_GetString(objv[1]), &db) ) return TCL_ERROR;

#ifndef SQLITE_OMIT_VIRTUALTABLE
  sqlite3_create_module(db, "echo", &echoModule, (void *)interp);
#endif
  return TCL_OK;
}


/*
** Register commands with the TCL interpreter.

** 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 1.2 2006/06/14 06:58:16 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include "tcl.h"
#include "os.h"
#include <stdlib.h>
#include <string.h>

................................................................................
#endif
  return SQLITE_OK;
}
/* Note that for this virtual table, the xCreate and xConnect
** methods are identical. */
static int tclvarDisconnect(sqlite3_vtab *pVtab){
  free(pVtab);

}
/* The xDisconnect and xDestroy methods are also the same */

static int tclvarOpen(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor){
  tclvar_cursor *pCur;
  pCur = sqliteMalloc(sizeof(tclvar_cursor));
  *ppCursor = &pCur->base;
................................................................................
/*
** A virtual table module that merely echos method calls into TCL
** variables.
*/
static sqlite3_module tclvarModule = {
  0,                         /* iVersion */
  "tclvar",                  /* zName */
  0,                         /* pAux */
  tclvarConnect,
  tclvarConnect,
  tclvarBestIndex,
  tclvarDisconnect, 
  tclvarDisconnect,
  tclvarOpen,                  /* xOpen - open a cursor */
  tclvarClose,                 /* xClose - close a cursor */
................................................................................
){
  sqlite3 *db;
  if( objc!=2 ){
    Tcl_WrongNumArgs(interp, 1, objv, "DB");
    return TCL_ERROR;
  }
  if( getDbPointer(interp, Tcl_GetString(objv[1]), &db) ) return TCL_ERROR;
  tclvarModule.pAux = interp;
#ifndef SQLITE_OMIT_VIRTUALTABLE
  sqlite3_create_module(db, "tclvar", &tclvarModule);
#endif
  return TCL_OK;
}


/*
** Register commands with the TCL interpreter.

** 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 1.3 2006/06/15 04:28:13 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include "tcl.h"
#include "os.h"
#include <stdlib.h>
#include <string.h>

................................................................................
#endif
  return SQLITE_OK;
}
/* Note that for this virtual table, the xCreate and xConnect
** methods are identical. */
static int tclvarDisconnect(sqlite3_vtab *pVtab){
  free(pVtab);
  return SQLITE_OK;
}
/* The xDisconnect and xDestroy methods are also the same */

static int tclvarOpen(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor){
  tclvar_cursor *pCur;
  pCur = sqliteMalloc(sizeof(tclvar_cursor));
  *ppCursor = &pCur->base;
................................................................................
/*
** A virtual table module that merely echos method calls into TCL
** variables.
*/
static sqlite3_module tclvarModule = {
  0,                         /* iVersion */
  "tclvar",                  /* zName */

  tclvarConnect,
  tclvarConnect,
  tclvarBestIndex,
  tclvarDisconnect, 
  tclvarDisconnect,
  tclvarOpen,                  /* xOpen - open a cursor */
  tclvarClose,                 /* xClose - close a cursor */
................................................................................
){
  sqlite3 *db;
  if( objc!=2 ){
    Tcl_WrongNumArgs(interp, 1, objv, "DB");
    return TCL_ERROR;
  }
  if( getDbPointer(interp, Tcl_GetString(objv[1]), &db) ) return TCL_ERROR;

#ifndef SQLITE_OMIT_VIRTUALTABLE
  sqlite3_create_module(db, "tclvar", &tclvarModule, (void *)interp);
#endif
  return TCL_OK;
}


/*
** Register commands with the TCL interpreter.

**    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 1.11 2006/06/14 13:03:24 danielk1977 Exp $
*/
#ifndef SQLITE_OMIT_VIRTUALTABLE
#include "sqliteInt.h"

/*
** External API function used to create a new virtual-table module.
*/
int sqlite3_create_module(
  sqlite3 *db,                    /* Database in which module is registered */
  const char *zName,              /* Name assigned to this module */
  const sqlite3_module *pModule   /* The definition of the module */

){








  sqlite3HashInsert(&db->aModule, zName, strlen(zName), (void*)pModule);

  sqlite3ResetInternalSchema(db, 0);
  return SQLITE_OK;


}

/*
** Clear any and all virtual-table information from the Table record.
** This routine is called, for example, just before deleting the Table
** record.
*/
void sqlite3VtabClear(Table *p){
  if( p->pVtab ){
    assert( p->pModule!=0 );
    p->pModule->xDisconnect(p->pVtab);
  }
  if( p->azModuleArg ){
    int i;
    for(i=0; i<p->nModuleArg; i++){
      sqliteFree(p->azModuleArg[i]);
    }
    sqliteFree(p->azModuleArg);
................................................................................
** The parser calls this routine after the CREATE VIRTUAL TABLE statement
** has been completely parsed.
*/
void sqlite3VtabFinishParse(Parse *pParse, Token *pEnd){
  Table *pTab;        /* The table being constructed */
  sqlite3 *db;        /* The database connection */
  char *zModule;      /* The module name of the table: USING modulename */


  addArgumentToVtab(pParse);
  sqliteFree(pParse->zArg);
  pParse->zArg = 0;
  pParse->nArgAlloc = 0;

  /* Lookup the module name. */
  pTab = pParse->pNewTable;
  if( pTab==0 ) return;
  db = pParse->db;
  if( pTab->nModuleArg<1 ) return;
  zModule = pTab->azModuleArg[0];
  pTab->pModule = (sqlite3_module*)sqlite3HashFind(&db->aModule, 
                     zModule, strlen(zModule));
  
  /* If the CREATE VIRTUAL TABLE statement is being entered for the
  ** first time (in other words if the virtual table is actually being
  ** created now instead of just being read out of sqlite_master) then
  ** do additional initialization work and store the statement text
  ** in the sqlite_master table.
  */
  if( !db->init.busy ){
    char *zStmt;
    char *zWhere;
    int iDb;
    Vdbe *v;
    if( pTab->pModule==0 ){
      sqlite3ErrorMsg(pParse, "no such module: %s", zModule);
    }

    /* Compute the complete text of the CREATE VIRTUAL TABLE statement */
    if( pEnd ){
      pParse->sNameToken.n = pEnd->z - pParse->sNameToken.z + pEnd->n;
    }
................................................................................
** Invoke a virtual table constructor (either xCreate or xConnect). The
** pointer to the function to invoke is passed as the fourth parameter
** to this procedure.
*/
static int vtabCallConstructor(
  sqlite3 *db, 
  Table *pTab,
  sqlite3_module *pModule,
  int (*xConstruct)(sqlite3*, void *, int, char **, sqlite3_vtab **),
  char **pzErr
){
  int rc;
  int rc2;
  char **azArg = pTab->azModuleArg;
  int nArg = pTab->nModuleArg;
................................................................................

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

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

  if( SQLITE_OK!=rc ){
    *pzErr = sqlite3MPrintf("vtable constructor failed: %s", pTab->zName);
  } else if( db->pVTab ){
    const char *zFormat = "vtable constructor did not declare schema: %s";
    *pzErr = sqlite3MPrintf(zFormat, pTab->zName);
................................................................................
** 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.
**
** This call is a no-op if table pTab is not a virtual table.
*/
int sqlite3VtabCallConnect(Parse *pParse, Table *pTab){
  sqlite3_module *pModule;
  const char *zModule;
  int rc = SQLITE_OK;

  if( !pTab || !pTab->isVirtual || pTab->pVtab ){
    return SQLITE_OK;
  }

  pModule = pTab->pModule;
  zModule = pTab->azModuleArg[0];
  if( !pModule ){
    const char *zModule = pTab->azModuleArg[0];
    sqlite3ErrorMsg(pParse, "no such module: %s", zModule);
    rc = SQLITE_ERROR;
  } else {
    char *zErr = 0;
    rc = vtabCallConstructor(pParse->db,pTab,pModule,pModule->xConnect,&zErr);

    if( rc!=SQLITE_OK ){
      sqlite3ErrorMsg(pParse, "%s", zErr);
    }
    sqliteFree(zErr);
  }

  return rc;
................................................................................
** If an error occurs, *pzErr is set to point an an English language
** description of the error and an SQLITE_XXX error code is returned.
** In this case the caller must call sqliteFree() on *pzErr.
*/
int sqlite3VtabCallCreate(sqlite3 *db, int iDb, const char *zTab, char **pzErr){
  int rc = SQLITE_OK;
  Table *pTab;
  sqlite3_module *pModule;
  const char *zModule;

  pTab = sqlite3FindTable(db, zTab, db->aDb[iDb].zName);
  assert(pTab && pTab->isVirtual && !pTab->pVtab);
  pModule = pTab->pModule;
  zModule = pTab->azModuleArg[0];

  /* If the module has been registered and includes a Create method, 
  ** invoke it now. If the module has not been registered, return an 
  ** error. Otherwise, do nothing.
  */
  if( !pModule ){
    *pzErr = sqlite3MPrintf("no such module: %s", zModule);
    rc = SQLITE_ERROR;
  }else{
    rc = vtabCallConstructor(db, pTab, pModule, pModule->xCreate, pzErr);
  }

  return rc;
}

/*
** This function is used to set the schema of a virtual table.  It is only
................................................................................
**
** This call is a no-op if zTab is not a virtual table.
*/
int sqlite3VtabCallDestroy(sqlite3 *db, int iDb, const char *zTab)
{
  int rc = SQLITE_OK;
  Table *pTab;
  sqlite3_module *pModule;

  pTab = sqlite3FindTable(db, zTab, db->aDb[iDb].zName);
  pModule = pTab->pModule;
  assert(pTab);
  if( pTab->pVtab ){

    rc = sqlite3SafetyOff(db);
    assert( rc==SQLITE_OK );

    rc = pModule->xDestroy(pTab->pVtab);

    sqlite3SafetyOn(db);
    if( rc==SQLITE_OK ){
      pTab->pVtab = 0;
    }
  }

  return rc;
}

#endif /* SQLITE_OMIT_VIRTUALTABLE */

**    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 1.12 2006/06/15 04:28:13 danielk1977 Exp $
*/
#ifndef SQLITE_OMIT_VIRTUALTABLE
#include "sqliteInt.h"

/*
** External API function used to create a new virtual-table module.
*/
int sqlite3_create_module(
  sqlite3 *db,                    /* Database in which module is registered */
  const char *zName,              /* Name assigned to this module */
  const sqlite3_module *pModule,  /* The definition of the module */
  void *pAux                      /* Context pointer for xCreate/xConnect */
){
  int nName = strlen(zName);
  Module *pMod = (Module *)sqliteMallocRaw(sizeof(Module) + nName + 1);
  if( pMod ){
    char *zCopy = (char *)(&pMod[1]);
    strcpy(zCopy, zName);
    pMod->zName = zCopy;
    pMod->pModule = pModule;
    pMod->pAux = pAux;
    pMod = (Module *)sqlite3HashInsert(&db->aModule, zCopy, nName, (void*)pMod);
    sqliteFree(pMod);
    sqlite3ResetInternalSchema(db, 0);

  }
  return sqlite3ApiExit(db, SQLITE_OK);
}

/*
** Clear any and all virtual-table information from the Table record.
** This routine is called, for example, just before deleting the Table
** record.
*/
void sqlite3VtabClear(Table *p){
  if( p->pVtab ){
    assert( p->pMod && p->pMod->pModule );
    p->pMod->pModule->xDisconnect(p->pVtab);
  }
  if( p->azModuleArg ){
    int i;
    for(i=0; i<p->nModuleArg; i++){
      sqliteFree(p->azModuleArg[i]);
    }
    sqliteFree(p->azModuleArg);
................................................................................
** The parser calls this routine after the CREATE VIRTUAL TABLE statement
** has been completely parsed.
*/
void sqlite3VtabFinishParse(Parse *pParse, Token *pEnd){
  Table *pTab;        /* The table being constructed */
  sqlite3 *db;        /* The database connection */
  char *zModule;      /* The module name of the table: USING modulename */
  Module *pMod = 0;

  addArgumentToVtab(pParse);
  sqliteFree(pParse->zArg);
  pParse->zArg = 0;
  pParse->nArgAlloc = 0;

  /* Lookup the module name. */
  pTab = pParse->pNewTable;
  if( pTab==0 ) return;
  db = pParse->db;
  if( pTab->nModuleArg<1 ) return;
  zModule = pTab->azModuleArg[0];
  pMod = (Module *)sqlite3HashFind(&db->aModule, zModule, strlen(zModule));
  pTab->pMod = pMod;
  
  /* If the CREATE VIRTUAL TABLE statement is being entered for the
  ** first time (in other words if the virtual table is actually being
  ** created now instead of just being read out of sqlite_master) then
  ** do additional initialization work and store the statement text
  ** in the sqlite_master table.
  */
  if( !db->init.busy ){
    char *zStmt;
    char *zWhere;
    int iDb;
    Vdbe *v;
    if( !pMod ){
      sqlite3ErrorMsg(pParse, "no such module: %s", zModule);
    }

    /* Compute the complete text of the CREATE VIRTUAL TABLE statement */
    if( pEnd ){
      pParse->sNameToken.n = pEnd->z - pParse->sNameToken.z + pEnd->n;
    }
................................................................................
** Invoke a virtual table constructor (either xCreate or xConnect). The
** 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;
  char **azArg = pTab->azModuleArg;
  int nArg = pTab->nModuleArg;
................................................................................

  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);
  if( pTab->pVtab ){
    pTab->pVtab->pModule = pMod->pModule;
  }

  if( SQLITE_OK!=rc ){
    *pzErr = sqlite3MPrintf("vtable constructor failed: %s", pTab->zName);
  } else if( db->pVTab ){
    const char *zFormat = "vtable constructor did not declare schema: %s";
    *pzErr = sqlite3MPrintf(zFormat, pTab->zName);
................................................................................
** 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.
**
** This call is a no-op if table pTab is not a virtual table.
*/
int sqlite3VtabCallConnect(Parse *pParse, Table *pTab){
  Module *pMod;
  const char *zModule;
  int rc = SQLITE_OK;

  if( !pTab || !pTab->isVirtual || pTab->pVtab ){
    return SQLITE_OK;
  }

  pMod = pTab->pMod;
  zModule = pTab->azModuleArg[0];
  if( !pMod ){
    const char *zModule = pTab->azModuleArg[0];
    sqlite3ErrorMsg(pParse, "no such module: %s", zModule);
    rc = SQLITE_ERROR;
  } else {
    char *zErr = 0;
    sqlite3 *db = pParse->db;
    rc = vtabCallConstructor(db, pTab, pMod, pMod->pModule->xConnect, &zErr);
    if( rc!=SQLITE_OK ){
      sqlite3ErrorMsg(pParse, "%s", zErr);
    }
    sqliteFree(zErr);
  }

  return rc;
................................................................................
** If an error occurs, *pzErr is set to point an an English language
** description of the error and an SQLITE_XXX error code is returned.
** In this case the caller must call sqliteFree() on *pzErr.
*/
int sqlite3VtabCallCreate(sqlite3 *db, int iDb, const char *zTab, char **pzErr){
  int rc = SQLITE_OK;
  Table *pTab;
  Module *pMod;
  const char *zModule;

  pTab = sqlite3FindTable(db, zTab, db->aDb[iDb].zName);
  assert(pTab && pTab->isVirtual && !pTab->pVtab);
  pMod = pTab->pMod;
  zModule = pTab->azModuleArg[0];

  /* If the module has been registered and includes a Create method, 
  ** invoke it now. If the module has not been registered, return an 
  ** error. Otherwise, do nothing.
  */
  if( !pMod ){
    *pzErr = sqlite3MPrintf("no such module: %s", zModule);
    rc = SQLITE_ERROR;
  }else{
    rc = vtabCallConstructor(db, pTab, pMod, pMod->pModule->xCreate, pzErr);
  }

  return rc;
}

/*
** This function is used to set the schema of a virtual table.  It is only
................................................................................
**
** This call is a no-op if zTab is not a virtual table.
*/
int sqlite3VtabCallDestroy(sqlite3 *db, int iDb, const char *zTab)
{
  int rc = SQLITE_OK;
  Table *pTab;


  pTab = sqlite3FindTable(db, zTab, db->aDb[iDb].zName);

  assert(pTab);
  if( pTab->pVtab ){
    int (*xDestroy)(sqlite3_vtab *pVTab) = pTab->pMod->pModule->xDestroy;
    rc = sqlite3SafetyOff(db);
    assert( rc==SQLITE_OK );
    if( xDestroy ){
      rc = xDestroy(pTab->pVtab);
    }
    sqlite3SafetyOn(db);
    if( rc==SQLITE_OK ){
      pTab->pVtab = 0;
    }
  }

  return rc;
}

#endif /* SQLITE_OMIT_VIRTUALTABLE */