**    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 1.748 2008/07/31 17:35:45 drh Exp $
*/
#ifndef _SQLITEINT_H_
#define _SQLITEINT_H_

/*
** Include the configuration header output by 'configure' if we're using the
** autoconf-based build
................................................................................
#  define sqlite3VtabClear(X)
#  define sqlite3VtabSync(X,Y) (Y)
#  define sqlite3VtabRollback(X)
#  define sqlite3VtabCommit(X)
#  define sqlite3VtabTransferError(A,B,C)
#else
   void sqlite3VtabClear(Table*);
   int sqlite3VtabSync(sqlite3 *db, int rc);
   int sqlite3VtabRollback(sqlite3 *db);
   int sqlite3VtabCommit(sqlite3 *db);
   void sqlite3VtabTransferError(sqlite3 *db, int, sqlite3_vtab*);
#endif
void sqlite3VtabMakeWritable(Parse*,Table*);
void sqlite3VtabLock(sqlite3_vtab*);
void sqlite3VtabUnlock(sqlite3*, sqlite3_vtab*);

**    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 1.749 2008/08/01 17:37:41 danielk1977 Exp $
*/
#ifndef _SQLITEINT_H_
#define _SQLITEINT_H_

/*
** Include the configuration header output by 'configure' if we're using the
** autoconf-based build
................................................................................
#  define sqlite3VtabClear(X)
#  define sqlite3VtabSync(X,Y) (Y)
#  define sqlite3VtabRollback(X)
#  define sqlite3VtabCommit(X)
#  define sqlite3VtabTransferError(A,B,C)
#else
   void sqlite3VtabClear(Table*);
   int sqlite3VtabSync(sqlite3 *db, char **);
   int sqlite3VtabRollback(sqlite3 *db);
   int sqlite3VtabCommit(sqlite3 *db);
   void sqlite3VtabTransferError(sqlite3 *db, int, sqlite3_vtab*);
#endif
void sqlite3VtabMakeWritable(Parse*,Table*);
void sqlite3VtabLock(sqlite3_vtab*);
void sqlite3VtabUnlock(sqlite3*, sqlite3_vtab*);

**    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 1.69 2008/07/28 19:34:54 drh Exp $
*/
#include "sqliteInt.h"
#include "tcl.h"
#include <stdlib.h>
#include <string.h>

#ifndef SQLITE_OMIT_VIRTUALTABLE
................................................................................
** This is used for automated testing of virtual table modules.
**
** The ::echo_module_sync_fail variable is set by test scripts and read
** by code in this file. If it is set to the name of a real table in the
** the database, then all xSync operations on echo virtual tables that
** use the named table as a backing store will fail.
*/

















/* 
** An echo virtual-table object.
**
** echo.vtab.aIndex is an array of booleans. The nth entry is true if 
** the nth column of the real table is the left-most column of an index
** (implicit or otherwise). In other words, if SQLite can optimize
................................................................................
};

/* An echo cursor object */
struct echo_cursor {
  sqlite3_vtab_cursor base;
  sqlite3_stmt *pStmt;
};













/*
** Convert an SQL-style quoted string into a normal string by removing
** the quote characters.  The conversion is done in-place.  If the
** input does not begin with a quote character, then this routine
** is a no-op.
**
................................................................................
}

/* 
** Echo virtual table module xOpen method.
*/
static int echoOpen(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor){
  echo_cursor *pCur;



  pCur = sqlite3MallocZero(sizeof(echo_cursor));
  *ppCursor = (sqlite3_vtab_cursor *)pCur;
  return (pCur ? SQLITE_OK : SQLITE_NOMEM);
}

/* 
** Echo virtual table module xClose method.
................................................................................

/* 
** Echo virtual table module xNext method.
*/
static int echoNext(sqlite3_vtab_cursor *cur){
  int rc = SQLITE_OK;
  echo_cursor *pCur = (echo_cursor *)cur;





  if( pCur->pStmt ){
    rc = sqlite3_step(pCur->pStmt);
    if( rc==SQLITE_ROW ){
      rc = SQLITE_OK;
    }else{
      rc = sqlite3_finalize(pCur->pStmt);
................................................................................

/* 
** Echo virtual table module xColumn method.
*/
static int echoColumn(sqlite3_vtab_cursor *cur, sqlite3_context *ctx, int i){
  int iCol = i + 1;
  sqlite3_stmt *pStmt = ((echo_cursor *)cur)->pStmt;





  if( !pStmt ){
    sqlite3_result_null(ctx);
  }else{
    assert( sqlite3_data_count(pStmt)>iCol );
    sqlite3_result_value(ctx, sqlite3_column_value(pStmt, iCol));
  }
  return SQLITE_OK;
................................................................................
}

/* 
** Echo virtual table module xRowid method.
*/
static int echoRowid(sqlite3_vtab_cursor *cur, sqlite_int64 *pRowid){
  sqlite3_stmt *pStmt = ((echo_cursor *)cur)->pStmt;





  *pRowid = sqlite3_column_int64(pStmt, 0);
  return SQLITE_OK;
}

/*
** Compute a simple hash of the null terminated string zString.
**
................................................................................
){
  int rc;
  int i;

  echo_cursor *pCur = (echo_cursor *)pVtabCursor;
  echo_vtab *pVtab = (echo_vtab *)pVtabCursor->pVtab;
  sqlite3 *db = pVtab->db;





  /* Check that idxNum matches idxStr */
  assert( idxNum==hashString(idxStr) );

  /* Log arguments to the ::echo_module Tcl variable */
  appendToEchoModule(pVtab->interp, "xFilter");
  appendToEchoModule(pVtab->interp, idxStr);
................................................................................
  Tcl_Interp *interp = pVtab->interp;

  int nRow;
  int useIdx = 0;
  int rc = SQLITE_OK;
  int useCost = 0;
  double cost;

  int isIgnoreUsable = 0;
  if( Tcl_GetVar(interp, "echo_module_ignore_usable", TCL_GLOBAL_ONLY) ){
    isIgnoreUsable = 1;
  }





  /* Determine the number of rows in the table and store this value in local
  ** variable nRow. The 'estimated-cost' of the scan will be the number of
  ** rows in the table for a linear scan, or the log (base 2) of the 
  ** number of rows if the proposed scan uses an index.  
  */
  if( Tcl_GetVar(interp, "echo_module_cost", TCL_GLOBAL_ONLY) ){
................................................................................
  int i;                     /* Counter variable used by for loops */

  assert( nData==pVtab->nCol+2 || nData==1 );

  /* Ticket #3083 - make sure we always start a transaction prior to
  ** making any changes to a virtual table */
  assert( pVtab->inTransaction );





  /* If apData[0] is an integer and nData>1 then do an UPDATE */
  if( nData>1 && sqlite3_value_type(apData[0])==SQLITE_INTEGER ){
    char *zSep = " SET";
    z = sqlite3_mprintf("UPDATE %Q", pVtab->zTableName);
    if( !z ){
      rc = SQLITE_NOMEM;
................................................................................
  echo_vtab *pVtab = (echo_vtab *)tab;
  Tcl_Interp *interp = pVtab->interp;
  const char *zVal; 

  /* Ticket #3083 - do not start a transaction if we are already in
  ** a transaction */
  assert( !pVtab->inTransaction );





  rc = echoTransactionCall(tab, "xBegin");

  if( rc==SQLITE_OK ){
    /* Check if the $::echo_module_begin_fail variable is defined. If it is,
    ** and it is set to the name of the real table underlying this virtual
    ** echo module table, then cause this xSync operation to fail.
................................................................................
  echo_vtab *pVtab = (echo_vtab *)tab;
  Tcl_Interp *interp = pVtab->interp;
  const char *zVal; 

  /* Ticket #3083 - Only call xSync if we have previously started a
  ** transaction */
  assert( pVtab->inTransaction );





  rc = echoTransactionCall(tab, "xSync");

  if( rc==SQLITE_OK ){
    /* Check if the $::echo_module_sync_fail variable is defined. If it is,
    ** and it is set to the name of the real table underlying this virtual
    ** echo module table, then cause this xSync operation to fail.
................................................................................
static int echoCommit(sqlite3_vtab *tab){
  echo_vtab *pVtab = (echo_vtab*)tab;
  int rc;

  /* Ticket #3083 - Only call xCommit if we have previously started
  ** a transaction */
  assert( pVtab->inTransaction );





  sqlite3BeginBenignMalloc();
  rc = echoTransactionCall(tab, "xCommit");
  sqlite3EndBenignMalloc();
  pVtab->inTransaction = 0;
  return rc;
}

**    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 1.70 2008/08/01 17:37:41 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include "tcl.h"
#include <stdlib.h>
#include <string.h>

#ifndef SQLITE_OMIT_VIRTUALTABLE
................................................................................
** This is used for automated testing of virtual table modules.
**
** The ::echo_module_sync_fail variable is set by test scripts and read
** by code in this file. If it is set to the name of a real table in the
** the database, then all xSync operations on echo virtual tables that
** use the named table as a backing store will fail.
*/

/*
** Errors can be provoked within the following echo virtual table methods:
**
**   xBestIndex   xOpen     xFilter   xNext   
**   xColumn      xRowid    xUpdate   xSync   
**   xBegin
**
** This is done by setting the global tcl variable:
**
**   echo_module_fail($method,$tbl)
**
** where $method is set to the name of the virtual table method to fail
** (i.e. "xBestIndex") and $tbl is the name of the table being echoed (not
** the name of the virtual table, the name of the underlying real table).
*/

/* 
** An echo virtual-table object.
**
** echo.vtab.aIndex is an array of booleans. The nth entry is true if 
** the nth column of the real table is the left-most column of an index
** (implicit or otherwise). In other words, if SQLite can optimize
................................................................................
};

/* An echo cursor object */
struct echo_cursor {
  sqlite3_vtab_cursor base;
  sqlite3_stmt *pStmt;
};

static int simulateVtabError(echo_vtab *p, const char *zMethod){
  const char *zErr;
  char zVarname[128];
  zVarname[127] = '\0';
  snprintf(zVarname, 127, "echo_module_fail(%s,%s)", zMethod, p->zTableName);
  zErr = Tcl_GetVar(p->interp, zVarname, TCL_GLOBAL_ONLY);
  if( zErr ){
    p->base.zErrMsg = sqlite3_mprintf("echo-vtab-error: %s", zErr);
  }
  return (zErr!=0);
}

/*
** Convert an SQL-style quoted string into a normal string by removing
** the quote characters.  The conversion is done in-place.  If the
** input does not begin with a quote character, then this routine
** is a no-op.
**
................................................................................
}

/* 
** Echo virtual table module xOpen method.
*/
static int echoOpen(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor){
  echo_cursor *pCur;
  if( simulateVtabError((echo_vtab *)pVTab, "xOpen") ){
    return SQLITE_ERROR;
  }
  pCur = sqlite3MallocZero(sizeof(echo_cursor));
  *ppCursor = (sqlite3_vtab_cursor *)pCur;
  return (pCur ? SQLITE_OK : SQLITE_NOMEM);
}

/* 
** Echo virtual table module xClose method.
................................................................................

/* 
** Echo virtual table module xNext method.
*/
static int echoNext(sqlite3_vtab_cursor *cur){
  int rc = SQLITE_OK;
  echo_cursor *pCur = (echo_cursor *)cur;

  if( simulateVtabError((echo_vtab *)(cur->pVtab), "xNext") ){
    return SQLITE_ERROR;
  }

  if( pCur->pStmt ){
    rc = sqlite3_step(pCur->pStmt);
    if( rc==SQLITE_ROW ){
      rc = SQLITE_OK;
    }else{
      rc = sqlite3_finalize(pCur->pStmt);
................................................................................

/* 
** Echo virtual table module xColumn method.
*/
static int echoColumn(sqlite3_vtab_cursor *cur, sqlite3_context *ctx, int i){
  int iCol = i + 1;
  sqlite3_stmt *pStmt = ((echo_cursor *)cur)->pStmt;

  if( simulateVtabError((echo_vtab *)(cur->pVtab), "xColumn") ){
    return SQLITE_ERROR;
  }

  if( !pStmt ){
    sqlite3_result_null(ctx);
  }else{
    assert( sqlite3_data_count(pStmt)>iCol );
    sqlite3_result_value(ctx, sqlite3_column_value(pStmt, iCol));
  }
  return SQLITE_OK;
................................................................................
}

/* 
** Echo virtual table module xRowid method.
*/
static int echoRowid(sqlite3_vtab_cursor *cur, sqlite_int64 *pRowid){
  sqlite3_stmt *pStmt = ((echo_cursor *)cur)->pStmt;

  if( simulateVtabError((echo_vtab *)(cur->pVtab), "xRowid") ){
    return SQLITE_ERROR;
  }

  *pRowid = sqlite3_column_int64(pStmt, 0);
  return SQLITE_OK;
}

/*
** Compute a simple hash of the null terminated string zString.
**
................................................................................
){
  int rc;
  int i;

  echo_cursor *pCur = (echo_cursor *)pVtabCursor;
  echo_vtab *pVtab = (echo_vtab *)pVtabCursor->pVtab;
  sqlite3 *db = pVtab->db;

  if( simulateVtabError(pVtab, "xFilter") ){
    return SQLITE_ERROR;
  }

  /* Check that idxNum matches idxStr */
  assert( idxNum==hashString(idxStr) );

  /* Log arguments to the ::echo_module Tcl variable */
  appendToEchoModule(pVtab->interp, "xFilter");
  appendToEchoModule(pVtab->interp, idxStr);
................................................................................
  Tcl_Interp *interp = pVtab->interp;

  int nRow;
  int useIdx = 0;
  int rc = SQLITE_OK;
  int useCost = 0;
  double cost;

  int isIgnoreUsable = 0;
  if( Tcl_GetVar(interp, "echo_module_ignore_usable", TCL_GLOBAL_ONLY) ){
    isIgnoreUsable = 1;
  }

  if( simulateVtabError(pVtab, "xBestIndex") ){
    return SQLITE_ERROR;
  }

  /* Determine the number of rows in the table and store this value in local
  ** variable nRow. The 'estimated-cost' of the scan will be the number of
  ** rows in the table for a linear scan, or the log (base 2) of the 
  ** number of rows if the proposed scan uses an index.  
  */
  if( Tcl_GetVar(interp, "echo_module_cost", TCL_GLOBAL_ONLY) ){
................................................................................
  int i;                     /* Counter variable used by for loops */

  assert( nData==pVtab->nCol+2 || nData==1 );

  /* Ticket #3083 - make sure we always start a transaction prior to
  ** making any changes to a virtual table */
  assert( pVtab->inTransaction );

  if( simulateVtabError(pVtab, "xUpdate") ){
    return SQLITE_ERROR;
  }

  /* If apData[0] is an integer and nData>1 then do an UPDATE */
  if( nData>1 && sqlite3_value_type(apData[0])==SQLITE_INTEGER ){
    char *zSep = " SET";
    z = sqlite3_mprintf("UPDATE %Q", pVtab->zTableName);
    if( !z ){
      rc = SQLITE_NOMEM;
................................................................................
  echo_vtab *pVtab = (echo_vtab *)tab;
  Tcl_Interp *interp = pVtab->interp;
  const char *zVal; 

  /* Ticket #3083 - do not start a transaction if we are already in
  ** a transaction */
  assert( !pVtab->inTransaction );

  if( simulateVtabError(pVtab, "xBegin") ){
    return SQLITE_ERROR;
  }

  rc = echoTransactionCall(tab, "xBegin");

  if( rc==SQLITE_OK ){
    /* Check if the $::echo_module_begin_fail variable is defined. If it is,
    ** and it is set to the name of the real table underlying this virtual
    ** echo module table, then cause this xSync operation to fail.
................................................................................
  echo_vtab *pVtab = (echo_vtab *)tab;
  Tcl_Interp *interp = pVtab->interp;
  const char *zVal; 

  /* Ticket #3083 - Only call xSync if we have previously started a
  ** transaction */
  assert( pVtab->inTransaction );

  if( simulateVtabError(pVtab, "xSync") ){
    return SQLITE_ERROR;
  }

  rc = echoTransactionCall(tab, "xSync");

  if( rc==SQLITE_OK ){
    /* Check if the $::echo_module_sync_fail variable is defined. If it is,
    ** and it is set to the name of the real table underlying this virtual
    ** echo module table, then cause this xSync operation to fail.
................................................................................
static int echoCommit(sqlite3_vtab *tab){
  echo_vtab *pVtab = (echo_vtab*)tab;
  int rc;

  /* Ticket #3083 - Only call xCommit if we have previously started
  ** a transaction */
  assert( pVtab->inTransaction );

  if( simulateVtabError(pVtab, "xCommit") ){
    return SQLITE_ERROR;
  }

  sqlite3BeginBenignMalloc();
  rc = echoTransactionCall(tab, "xCommit");
  sqlite3EndBenignMalloc();
  pVtab->inTransaction = 0;
  return rc;
}

**
** Various scripts scan this source file in order to generate HTML
** documentation, headers files, or other derived files.  The formatting
** of the code in this file is, therefore, important.  See other comments
** in this file for details.  If in doubt, do not deviate from existing
** commenting and indentation practices when changing or adding code.
**
** $Id: vdbe.c,v 1.769 2008/07/30 13:27:11 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>
#include "vdbeInt.h"

/*
** The following global variable is incremented every time a cursor
................................................................................
  break;
}
#endif /* SQLITE_OMIT_SHARED_CACHE */

#ifndef SQLITE_OMIT_VIRTUALTABLE
/* Opcode: VBegin * * * P4 *
**
** P4 a pointer to an sqlite3_vtab structure. Call the xBegin method 
** for that table.




*/
case OP_VBegin: {

  rc = sqlite3VtabBegin(db, pOp->p4.pVtab);





  break;
}
#endif /* SQLITE_OMIT_VIRTUALTABLE */

#ifndef SQLITE_OMIT_VIRTUALTABLE
/* Opcode: VCreate P1 * * P4 *
**
................................................................................
      storeTypeInfo(apArg[i], 0);
    }

    if( sqlite3SafetyOff(db) ) goto abort_due_to_misuse;
    p->inVtabMethod = 1;
    rc = pModule->xFilter(pVtabCursor, iQuery, pOp->p4.z, nArg, apArg);
    p->inVtabMethod = 0;



    if( rc==SQLITE_OK ){
      res = pModule->xEof(pVtabCursor);
    }
    if( sqlite3SafetyOn(db) ) goto abort_due_to_misuse;

    if( res ){
      pc = pOp->p2 - 1;
................................................................................
#ifndef SQLITE_OMIT_VIRTUALTABLE
/* Opcode: VRowid P1 P2 * * *
**
** Store into register P2  the rowid of
** the virtual-table that the P1 cursor is pointing to.
*/
case OP_VRowid: {             /* out2-prerelease */

  const sqlite3_module *pModule;
  sqlite_int64 iRow;
  Cursor *pCur = p->apCsr[pOp->p1];

  assert( pCur->pVtabCursor );
  if( pCur->nullRow ){
    break;
  }
  pModule = pCur->pVtabCursor->pVtab->pModule;

  assert( pModule->xRowid );
  if( sqlite3SafetyOff(db) ) goto abort_due_to_misuse;
  rc = pModule->xRowid(pCur->pVtabCursor, &iRow);



  if( sqlite3SafetyOn(db) ) goto abort_due_to_misuse;
  MemSetTypeFlag(pOut, MEM_Int);
  pOut->u.i = iRow;
  break;
}
#endif /* SQLITE_OMIT_VIRTUALTABLE */

................................................................................
/* Opcode: VColumn P1 P2 P3 * *
**
** Store the value of the P2-th column of
** the row of the virtual-table that the 
** P1 cursor is pointing to into register P3.
*/
case OP_VColumn: {

  const sqlite3_module *pModule;
  Mem *pDest;
  sqlite3_context sContext;

  Cursor *pCur = p->apCsr[pOp->p1];
  assert( pCur->pVtabCursor );
  assert( pOp->p3>0 && pOp->p3<=p->nMem );
  pDest = &p->aMem[pOp->p3];
  if( pCur->nullRow ){
    sqlite3VdbeMemSetNull(pDest);
    break;
  }
  pModule = pCur->pVtabCursor->pVtab->pModule;

  assert( pModule->xColumn );
  memset(&sContext, 0, sizeof(sContext));

  /* The output cell may already have a buffer allocated. Move
  ** the current contents to sContext.s so in case the user-function 
  ** can use the already allocated buffer instead of allocating a 
  ** new one.
  */
  sqlite3VdbeMemMove(&sContext.s, pDest);
  MemSetTypeFlag(&sContext.s, MEM_Null);

  if( sqlite3SafetyOff(db) ) goto abort_due_to_misuse;
  rc = pModule->xColumn(pCur->pVtabCursor, &sContext, pOp->p2);




  /* Copy the result of the function to the P3 register. We
  ** do this regardless of whether or not an error occured to ensure any
  ** dynamic allocation in sContext.s (a Mem struct) is  released.
  */
  sqlite3VdbeChangeEncoding(&sContext.s, encoding);
  REGISTER_TRACE(pOp->p3, pDest);
................................................................................
/* Opcode: VNext P1 P2 * * *
**
** Advance virtual table P1 to the next row in its result set and
** jump to instruction P2.  Or, if the virtual table has reached
** the end of its result set, then fall through to the next instruction.
*/
case OP_VNext: {   /* jump */

  const sqlite3_module *pModule;
  int res = 0;

  Cursor *pCur = p->apCsr[pOp->p1];
  assert( pCur->pVtabCursor );
  if( pCur->nullRow ){
    break;
  }
  pModule = pCur->pVtabCursor->pVtab->pModule;

  assert( pModule->xNext );

  /* Invoke the xNext() method of the module. There is no way for the
  ** underlying implementation to return an error if one occurs during
  ** xNext(). Instead, if an error occurs, true is returned (indicating that 
  ** data is available) and the error code returned when xColumn or
  ** some other method is next invoked on the save virtual table cursor.
  */
  if( sqlite3SafetyOff(db) ) goto abort_due_to_misuse;
  p->inVtabMethod = 1;
  rc = pModule->xNext(pCur->pVtabCursor);
  p->inVtabMethod = 0;



  if( rc==SQLITE_OK ){
    res = pModule->xEof(pCur->pVtabCursor);
  }
  if( sqlite3SafetyOn(db) ) goto abort_due_to_misuse;

  if( !res ){
    /* If there is data, jump to P2 */

**
** Various scripts scan this source file in order to generate HTML
** documentation, headers files, or other derived files.  The formatting
** of the code in this file is, therefore, important.  See other comments
** in this file for details.  If in doubt, do not deviate from existing
** commenting and indentation practices when changing or adding code.
**
** $Id: vdbe.c,v 1.770 2008/08/01 17:37:41 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>
#include "vdbeInt.h"

/*
** The following global variable is incremented every time a cursor
................................................................................
  break;
}
#endif /* SQLITE_OMIT_SHARED_CACHE */

#ifndef SQLITE_OMIT_VIRTUALTABLE
/* Opcode: VBegin * * * P4 *
**
** P4 may be a pointer to an sqlite3_vtab structure. If so, call the 
** xBegin method for that table.
**
** Also, whether or not P4 is set, check that this is not being called from
** within a callback to a virtual table xSync() method. If it is, set the
** error code to SQLITE_LOCKED.
*/
case OP_VBegin: {
  sqlite3_vtab *pVtab = pOp->p4.pVtab;
  rc = sqlite3VtabBegin(db, pVtab);
  if( pVtab ){
    sqlite3DbFree(db, p->zErrMsg);
    p->zErrMsg = pVtab->zErrMsg;
    pVtab->zErrMsg = 0;
  }
  break;
}
#endif /* SQLITE_OMIT_VIRTUALTABLE */

#ifndef SQLITE_OMIT_VIRTUALTABLE
/* Opcode: VCreate P1 * * P4 *
**
................................................................................
      storeTypeInfo(apArg[i], 0);
    }

    if( sqlite3SafetyOff(db) ) goto abort_due_to_misuse;
    p->inVtabMethod = 1;
    rc = pModule->xFilter(pVtabCursor, iQuery, pOp->p4.z, nArg, apArg);
    p->inVtabMethod = 0;
    sqlite3DbFree(db, p->zErrMsg);
    p->zErrMsg = pVtab->zErrMsg;
    pVtab->zErrMsg = 0;
    if( rc==SQLITE_OK ){
      res = pModule->xEof(pVtabCursor);
    }
    if( sqlite3SafetyOn(db) ) goto abort_due_to_misuse;

    if( res ){
      pc = pOp->p2 - 1;
................................................................................
#ifndef SQLITE_OMIT_VIRTUALTABLE
/* Opcode: VRowid P1 P2 * * *
**
** Store into register P2  the rowid of
** the virtual-table that the P1 cursor is pointing to.
*/
case OP_VRowid: {             /* out2-prerelease */
  sqlite3_vtab *pVtab;
  const sqlite3_module *pModule;
  sqlite_int64 iRow;
  Cursor *pCur = p->apCsr[pOp->p1];

  assert( pCur->pVtabCursor );
  if( pCur->nullRow ){
    break;
  }
  pVtab = pCur->pVtabCursor->pVtab;
  pModule = pVtab->pModule;
  assert( pModule->xRowid );
  if( sqlite3SafetyOff(db) ) goto abort_due_to_misuse;
  rc = pModule->xRowid(pCur->pVtabCursor, &iRow);
  sqlite3DbFree(db, p->zErrMsg);
  p->zErrMsg = pVtab->zErrMsg;
  pVtab->zErrMsg = 0;
  if( sqlite3SafetyOn(db) ) goto abort_due_to_misuse;
  MemSetTypeFlag(pOut, MEM_Int);
  pOut->u.i = iRow;
  break;
}
#endif /* SQLITE_OMIT_VIRTUALTABLE */

................................................................................
/* Opcode: VColumn P1 P2 P3 * *
**
** Store the value of the P2-th column of
** the row of the virtual-table that the 
** P1 cursor is pointing to into register P3.
*/
case OP_VColumn: {
  sqlite3_vtab *pVtab;
  const sqlite3_module *pModule;
  Mem *pDest;
  sqlite3_context sContext;

  Cursor *pCur = p->apCsr[pOp->p1];
  assert( pCur->pVtabCursor );
  assert( pOp->p3>0 && pOp->p3<=p->nMem );
  pDest = &p->aMem[pOp->p3];
  if( pCur->nullRow ){
    sqlite3VdbeMemSetNull(pDest);
    break;
  }
  pVtab = pCur->pVtabCursor->pVtab;
  pModule = pVtab->pModule;
  assert( pModule->xColumn );
  memset(&sContext, 0, sizeof(sContext));

  /* The output cell may already have a buffer allocated. Move
  ** the current contents to sContext.s so in case the user-function 
  ** can use the already allocated buffer instead of allocating a 
  ** new one.
  */
  sqlite3VdbeMemMove(&sContext.s, pDest);
  MemSetTypeFlag(&sContext.s, MEM_Null);

  if( sqlite3SafetyOff(db) ) goto abort_due_to_misuse;
  rc = pModule->xColumn(pCur->pVtabCursor, &sContext, pOp->p2);
  sqlite3DbFree(db, p->zErrMsg);
  p->zErrMsg = pVtab->zErrMsg;
  pVtab->zErrMsg = 0;

  /* Copy the result of the function to the P3 register. We
  ** do this regardless of whether or not an error occured to ensure any
  ** dynamic allocation in sContext.s (a Mem struct) is  released.
  */
  sqlite3VdbeChangeEncoding(&sContext.s, encoding);
  REGISTER_TRACE(pOp->p3, pDest);
................................................................................
/* Opcode: VNext P1 P2 * * *
**
** Advance virtual table P1 to the next row in its result set and
** jump to instruction P2.  Or, if the virtual table has reached
** the end of its result set, then fall through to the next instruction.
*/
case OP_VNext: {   /* jump */
  sqlite3_vtab *pVtab;
  const sqlite3_module *pModule;
  int res = 0;

  Cursor *pCur = p->apCsr[pOp->p1];
  assert( pCur->pVtabCursor );
  if( pCur->nullRow ){
    break;
  }
  pVtab = pCur->pVtabCursor->pVtab;
  pModule = pVtab->pModule;
  assert( pModule->xNext );

  /* Invoke the xNext() method of the module. There is no way for the
  ** underlying implementation to return an error if one occurs during
  ** xNext(). Instead, if an error occurs, true is returned (indicating that 
  ** data is available) and the error code returned when xColumn or
  ** some other method is next invoked on the save virtual table cursor.
  */
  if( sqlite3SafetyOff(db) ) goto abort_due_to_misuse;
  p->inVtabMethod = 1;
  rc = pModule->xNext(pCur->pVtabCursor);
  p->inVtabMethod = 0;
  sqlite3DbFree(db, p->zErrMsg);
  p->zErrMsg = pVtab->zErrMsg;
  pVtab->zErrMsg = 0;
  if( rc==SQLITE_OK ){
    res = pModule->xEof(pCur->pVtabCursor);
  }
  if( sqlite3SafetyOn(db) ) goto abort_due_to_misuse;

  if( !res ){
    /* If there is data, jump to P2 */

**
*************************************************************************
** This file contains code used for creating, destroying, and populating
** a VDBE (or an "sqlite3_stmt" as it is known to the outside world.)  Prior
** to version 2.8.7, all this code was combined into the vdbe.c source file.
** But that file was getting too big so this subroutines were split out.
**
** $Id: vdbeaux.c,v 1.402 2008/07/31 01:43:14 shane Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>
#include "vdbeInt.h"



................................................................................

/*
** A read or write transaction may or may not be active on database handle
** db. If a transaction is active, commit it. If there is a
** write-transaction spanning more than one database file, this routine
** takes care of the master journal trickery.
*/
static int vdbeCommit(sqlite3 *db){
  int i;
  int nTrans = 0;  /* Number of databases with an active write-transaction */
  int rc = SQLITE_OK;
  int needXcommit = 0;

  /* Before doing anything else, call the xSync() callback for any
  ** virtual module tables written in this transaction. This has to
  ** be done before determining whether a master journal file is 
  ** required, as an xSync() callback may add an attached database
  ** to the transaction.
  */
  rc = sqlite3VtabSync(db, rc);
  if( rc!=SQLITE_OK ){
    return rc;
  }

  /* This loop determines (a) if the commit hook should be invoked and
  ** (b) how many database files have open write transactions, not 
  ** including the temp database. (b) is important because if more than 
................................................................................
    */
    if( db->autoCommit && db->activeVdbeCnt==1 ){
      if( p->rc==SQLITE_OK || (p->errorAction==OE_Fail && !isSpecialError) ){
        /* The auto-commit flag is true, and the vdbe program was 
        ** successful or hit an 'OR FAIL' constraint. This means a commit 
        ** is required.
        */
        int rc = vdbeCommit(db);
        if( rc==SQLITE_BUSY ){
          sqlite3BtreeMutexArrayLeave(&p->aMutex);
          return SQLITE_BUSY;
        }else if( rc!=SQLITE_OK ){
          p->rc = rc;
          sqlite3RollbackAll(db);
        }else{

**
*************************************************************************
** This file contains code used for creating, destroying, and populating
** a VDBE (or an "sqlite3_stmt" as it is known to the outside world.)  Prior
** to version 2.8.7, all this code was combined into the vdbe.c source file.
** But that file was getting too big so this subroutines were split out.
**
** $Id: vdbeaux.c,v 1.403 2008/08/01 17:37:41 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>
#include "vdbeInt.h"



................................................................................

/*
** A read or write transaction may or may not be active on database handle
** db. If a transaction is active, commit it. If there is a
** write-transaction spanning more than one database file, this routine
** takes care of the master journal trickery.
*/
static int vdbeCommit(sqlite3 *db, Vdbe *p){
  int i;
  int nTrans = 0;  /* Number of databases with an active write-transaction */
  int rc = SQLITE_OK;
  int needXcommit = 0;

  /* Before doing anything else, call the xSync() callback for any
  ** virtual module tables written in this transaction. This has to
  ** be done before determining whether a master journal file is 
  ** required, as an xSync() callback may add an attached database
  ** to the transaction.
  */
  rc = sqlite3VtabSync(db, &p->zErrMsg);
  if( rc!=SQLITE_OK ){
    return rc;
  }

  /* This loop determines (a) if the commit hook should be invoked and
  ** (b) how many database files have open write transactions, not 
  ** including the temp database. (b) is important because if more than 
................................................................................
    */
    if( db->autoCommit && db->activeVdbeCnt==1 ){
      if( p->rc==SQLITE_OK || (p->errorAction==OE_Fail && !isSpecialError) ){
        /* The auto-commit flag is true, and the vdbe program was 
        ** successful or hit an 'OR FAIL' constraint. This means a commit 
        ** is required.
        */
        int rc = vdbeCommit(db, p);
        if( rc==SQLITE_BUSY ){
          sqlite3BtreeMutexArrayLeave(&p->aMutex);
          return SQLITE_BUSY;
        }else if( rc!=SQLITE_OK ){
          p->rc = rc;
          sqlite3RollbackAll(db);
        }else{

**    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 1.72 2008/07/28 19:34:54 drh Exp $
*/
#ifndef SQLITE_OMIT_VIRTUALTABLE
#include "sqliteInt.h"

static int createModule(
  sqlite3 *db,                    /* Database in which module is registered */
  const char *zName,              /* Name assigned to this module */
................................................................................
    sqlite3DbFree(db, db->aVTrans);
    db->nVTrans = 0;
    db->aVTrans = 0;
  }
}

/*
** If argument rc2 is not SQLITE_OK, then return it and do nothing. 
** Otherwise, invoke the xSync method of all virtual tables in the 
** sqlite3.aVTrans array. Return the error code for the first error 
** that occurs, or SQLITE_OK if all xSync operations are successful.



*/
int sqlite3VtabSync(sqlite3 *db, int rc2){
  int i;
  int rc = SQLITE_OK;
  int rcsafety;
  sqlite3_vtab **aVTrans = db->aVTrans;
  if( rc2!=SQLITE_OK ) return rc2;

  rc = sqlite3SafetyOff(db);
  db->aVTrans = 0;
  for(i=0; rc==SQLITE_OK && i<db->nVTrans && aVTrans[i]; i++){
    sqlite3_vtab *pVtab = aVTrans[i];
    int (*x)(sqlite3_vtab *);
    x = pVtab->pModule->xSync;
    if( x ){
      rc = x(pVtab);



    }
  }
  db->aVTrans = aVTrans;
  rcsafety = sqlite3SafetyOn(db);

  if( rc==SQLITE_OK ){
    rc = rcsafety;
................................................................................
      if( db->aVTrans[i]==pVtab ){
        return SQLITE_OK;
      }
    }

    /* Invoke the xBegin method */
    rc = pModule->xBegin(pVtab);
    sqlite3VtabTransferError(db, rc, pVtab);
    if( rc!=SQLITE_OK ){
      return rc;
    }

    rc = addToVTrans(db, pVtab);

  }
  return rc;
}

/*
** The first parameter (pDef) is a function implementation.  The
** second parameter (pExpr) is the first argument to this function.

**    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 1.73 2008/08/01 17:37:41 danielk1977 Exp $
*/
#ifndef SQLITE_OMIT_VIRTUALTABLE
#include "sqliteInt.h"

static int createModule(
  sqlite3 *db,                    /* Database in which module is registered */
  const char *zName,              /* Name assigned to this module */
................................................................................
    sqlite3DbFree(db, db->aVTrans);
    db->nVTrans = 0;
    db->aVTrans = 0;
  }
}

/*

** Invoke the xSync method of all virtual tables in the sqlite3.aVTrans
** array. Return the error code for the first error that occurs, or
** SQLITE_OK if all xSync operations are successful.
**
** Set *pzErrmsg to point to a buffer that should be released using 
** sqlite3DbFree() containing an error message, if one is available.
*/
int sqlite3VtabSync(sqlite3 *db, char **pzErrmsg){
  int i;
  int rc = SQLITE_OK;
  int rcsafety;
  sqlite3_vtab **aVTrans = db->aVTrans;


  rc = sqlite3SafetyOff(db);
  db->aVTrans = 0;
  for(i=0; rc==SQLITE_OK && i<db->nVTrans && aVTrans[i]; i++){
    sqlite3_vtab *pVtab = aVTrans[i];
    int (*x)(sqlite3_vtab *);
    x = pVtab->pModule->xSync;
    if( x ){
      rc = x(pVtab);
      sqlite3DbFree(db, *pzErrmsg);
      *pzErrmsg = pVtab->zErrMsg;
      pVtab->zErrMsg = 0;
    }
  }
  db->aVTrans = aVTrans;
  rcsafety = sqlite3SafetyOn(db);

  if( rc==SQLITE_OK ){
    rc = rcsafety;
................................................................................
      if( db->aVTrans[i]==pVtab ){
        return SQLITE_OK;
      }
    }

    /* Invoke the xBegin method */
    rc = pModule->xBegin(pVtab);

    if( rc==SQLITE_OK ){



      rc = addToVTrans(db, pVtab);
    }
  }
  return rc;
}

/*
** The first parameter (pDef) is a function implementation.  The
** second parameter (pExpr) is the first argument to this function.

** This module contains C code that generates VDBE code used to process
** the WHERE clause of SQL statements.  This module is responsible for
** generating the code that loops through a table looking for applicable
** rows.  Indices are selected and used to speed the search when doing
** so is applicable.  Because this module is responsible for selecting
** indices, you might also think of this module as the "query optimizer".
**
** $Id: where.c,v 1.318 2008/07/28 19:34:54 drh Exp $
*/
#include "sqliteInt.h"

/*
** The number of bits in a Bitmask.  "BMS" means "BitMask Size".
*/
#define BMS  (sizeof(Bitmask)*8)
................................................................................
  struct SrcList_item *pSrc,     /* The FROM clause term to search */
  Bitmask notReady,              /* Mask of cursors that are not available */
  ExprList *pOrderBy,            /* The order by clause */
  int orderByUsable,             /* True if we can potential sort */
  sqlite3_index_info **ppIdxInfo /* Index information passed to xBestIndex */
){
  Table *pTab = pSrc->pTab;

  sqlite3_index_info *pIdxInfo;
  struct sqlite3_index_constraint *pIdxCons;
  struct sqlite3_index_orderby *pIdxOrderBy;
  struct sqlite3_index_constraint_usage *pUsage;
  WhereTerm *pTerm;
  int i, j;
  int nOrderBy;
................................................................................
  */

  /* The module name must be defined. Also, by this point there must
  ** be a pointer to an sqlite3_vtab structure. Otherwise
  ** sqlite3ViewGetColumnNames() would have picked up the error. 
  */
  assert( pTab->azModuleArg && pTab->azModuleArg[0] );
  assert( pTab->pVtab );
#if 0
  if( pTab->pVtab==0 ){
    sqlite3ErrorMsg(pParse, "undefined module %s for table %s",
        pTab->azModuleArg[0], pTab->zName);
    return 0.0;
  }
#endif
................................................................................
  if( pIdxInfo->nOrderBy && !orderByUsable ){
    *(int*)&pIdxInfo->nOrderBy = 0;
  }

  (void)sqlite3SafetyOff(pParse->db);
  WHERETRACE(("xBestIndex for %s\n", pTab->zName));
  TRACE_IDX_INPUTS(pIdxInfo);
  rc = pTab->pVtab->pModule->xBestIndex(pTab->pVtab, pIdxInfo);
  TRACE_IDX_OUTPUTS(pIdxInfo);
  (void)sqlite3SafetyOn(pParse->db);













  for(i=0; i<pIdxInfo->nConstraint; i++){
    if( !pIdxInfo->aConstraint[i].usable && pUsage[i].argvIndex>0 ){
      sqlite3ErrorMsg(pParse, 
          "table %s: xBestIndex returned an invalid plan", pTab->zName);
      return 0.0;
    }
  }

  if( rc!=SQLITE_OK ){
    if( rc==SQLITE_NOMEM ){
      pParse->db->mallocFailed = 1;
    }else {
      sqlite3ErrorMsg(pParse, "%s", sqlite3ErrStr(rc));
    }
  }
  *(int*)&pIdxInfo->nOrderBy = nOrderBy;

  return pIdxInfo->estimatedCost;
}
#endif /* SQLITE_OMIT_VIRTUALTABLE */

/*
** Find the best index for accessing a particular table.  Return a pointer
** to the index, flags that describe how the index should be used, the

** This module contains C code that generates VDBE code used to process
** the WHERE clause of SQL statements.  This module is responsible for
** generating the code that loops through a table looking for applicable
** rows.  Indices are selected and used to speed the search when doing
** so is applicable.  Because this module is responsible for selecting
** indices, you might also think of this module as the "query optimizer".
**
** $Id: where.c,v 1.319 2008/08/01 17:37:41 danielk1977 Exp $
*/
#include "sqliteInt.h"

/*
** The number of bits in a Bitmask.  "BMS" means "BitMask Size".
*/
#define BMS  (sizeof(Bitmask)*8)
................................................................................
  struct SrcList_item *pSrc,     /* The FROM clause term to search */
  Bitmask notReady,              /* Mask of cursors that are not available */
  ExprList *pOrderBy,            /* The order by clause */
  int orderByUsable,             /* True if we can potential sort */
  sqlite3_index_info **ppIdxInfo /* Index information passed to xBestIndex */
){
  Table *pTab = pSrc->pTab;
  sqlite3_vtab *pVtab = pTab->pVtab;
  sqlite3_index_info *pIdxInfo;
  struct sqlite3_index_constraint *pIdxCons;
  struct sqlite3_index_orderby *pIdxOrderBy;
  struct sqlite3_index_constraint_usage *pUsage;
  WhereTerm *pTerm;
  int i, j;
  int nOrderBy;
................................................................................
  */

  /* The module name must be defined. Also, by this point there must
  ** be a pointer to an sqlite3_vtab structure. Otherwise
  ** sqlite3ViewGetColumnNames() would have picked up the error. 
  */
  assert( pTab->azModuleArg && pTab->azModuleArg[0] );
  assert( pVtab );
#if 0
  if( pTab->pVtab==0 ){
    sqlite3ErrorMsg(pParse, "undefined module %s for table %s",
        pTab->azModuleArg[0], pTab->zName);
    return 0.0;
  }
#endif
................................................................................
  if( pIdxInfo->nOrderBy && !orderByUsable ){
    *(int*)&pIdxInfo->nOrderBy = 0;
  }

  (void)sqlite3SafetyOff(pParse->db);
  WHERETRACE(("xBestIndex for %s\n", pTab->zName));
  TRACE_IDX_INPUTS(pIdxInfo);
  rc = pVtab->pModule->xBestIndex(pVtab, pIdxInfo);
  TRACE_IDX_OUTPUTS(pIdxInfo);
  (void)sqlite3SafetyOn(pParse->db);

  if( rc!=SQLITE_OK ){
    if( rc==SQLITE_NOMEM ){
      pParse->db->mallocFailed = 1;
    }else if( !pVtab->zErrMsg ){
      sqlite3ErrorMsg(pParse, "%s", sqlite3ErrStr(rc));
    }else{
      sqlite3ErrorMsg(pParse, "%s", pVtab->zErrMsg);
    }
  }
  sqlite3DbFree(pParse->db, pVtab->zErrMsg);
  pVtab->zErrMsg = 0;

  for(i=0; i<pIdxInfo->nConstraint; i++){
    if( !pIdxInfo->aConstraint[i].usable && pUsage[i].argvIndex>0 ){
      sqlite3ErrorMsg(pParse, 
          "table %s: xBestIndex returned an invalid plan", pTab->zName);
      return 0.0;
    }
  }








  *(int*)&pIdxInfo->nOrderBy = nOrderBy;

  return pIdxInfo->estimatedCost;
}
#endif /* SQLITE_OMIT_VIRTUALTABLE */

/*
** Find the best index for accessing a particular table.  Return a pointer
** to the index, flags that describe how the index should be used, the

#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
# This file implements regression tests for SQLite library.  The
# focus of this file is creating and dropping virtual tables.
#
# $Id: vtab1.test,v 1.55 2008/07/23 21:07:25 drh Exp $

set testdir [file dirname $argv0]
source $testdir/tester.tcl

ifcapable !vtab||!schema_pragmas {
  finish_test
  return
................................................................................
#----------------------------------------------------------------------
# Test cases vtab1.1.*
#

# We cannot create a virtual table if the module has not been registered.
#
do_test vtab1-1.1 {



  catchsql {
    CREATE VIRTUAL TABLE t1 USING echo;
  }
} {1 {no such module: echo}}
do_test vtab1-1.2 {
  execsql {
    SELECT name FROM sqlite_master ORDER BY 1
................................................................................
} {45 {} {} {} 46 {} {} {}}
do_test vtab1-15.4 {
  catchsql {
    INSERT INTO echo_t1(rowid) VALUES('new rowid');
  }
} {1 {datatype mismatch}}












































unset -nocomplain echo_module_begin_fail
finish_test

#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
# This file implements regression tests for SQLite library.  The
# focus of this file is creating and dropping virtual tables.
#
# $Id: vtab1.test,v 1.56 2008/08/01 17:37:41 danielk1977 Exp $

set testdir [file dirname $argv0]
source $testdir/tester.tcl

ifcapable !vtab||!schema_pragmas {
  finish_test
  return
................................................................................
#----------------------------------------------------------------------
# Test cases vtab1.1.*
#

# We cannot create a virtual table if the module has not been registered.
#
do_test vtab1-1.1 {
  explain {
    CREATE VIRTUAL TABLE t1 USING echo;
  }
  catchsql {
    CREATE VIRTUAL TABLE t1 USING echo;
  }
} {1 {no such module: echo}}
do_test vtab1-1.2 {
  execsql {
    SELECT name FROM sqlite_master ORDER BY 1
................................................................................
} {45 {} {} {} 46 {} {} {}}
do_test vtab1-15.4 {
  catchsql {
    INSERT INTO echo_t1(rowid) VALUES('new rowid');
  }
} {1 {datatype mismatch}}

# The following tests - vtab1-16.* - are designed to test that setting 
# sqlite3_vtab.zErrMsg variable can be used by the vtab interface to 
# return an error message to the user.
# 
do_test vtab1-16.1 {
  execsql {
    CREATE TABLE t2(a PRIMARY KEY, b, c);
    INSERT INTO t2 VALUES(1, 2, 3);
    INSERT INTO t2 VALUES(4, 5, 6);
    CREATE VIRTUAL TABLE echo_t2 USING echo(t2);
  }
} {}

set tn 2
foreach method [list \
    xBestIndex       \
    xOpen            \
    xFilter          \
    xNext            \
    xColumn          \
    xRowid           \
] {
  do_test vtab1-16.$tn {
    set echo_module_fail($method,t2) "the $method method has failed"
    catchsql { SELECT rowid, * FROM echo_t2 WHERE a >= 1 }
  } "1 {echo-vtab-error: the $method method has failed}"
  unset echo_module_fail($method,t2)
  incr tn
}

foreach method [list \
  xUpdate            \
  xBegin             \
  xSync              \
] {
  do_test vtab1-16.$tn {
    set echo_module_fail($method,t2) "the $method method has failed"
    catchsql { INSERT INTO echo_t2 VALUES(7, 8, 9) }
  } "1 {echo-vtab-error: the $method method has failed}"
  unset echo_module_fail($method,t2)
  incr tn
}

unset -nocomplain echo_module_begin_fail
finish_test