SQLite

**    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 1.187 2006/07/08 18:09:15 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++.

  int (*xRowid)(sqlite3_vtab_cursor*, sqlite_int64 *pRowid);
  int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite_int64 *);
  int (*xBegin)(sqlite3_vtab *pVTab);
  int (*xSync)(sqlite3_vtab *pVTab);
  int (*xCommit)(sqlite3_vtab *pVTab);
  int (*xRollback)(sqlite3_vtab *pVTab);
  int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName,
                       void (**pxFunc)(sqlite3_context*,int,sqlite3_value**),
                       void **ppArg);
};

/*
** The sqlite3_index_info structure and its substructures is used to
** pass information into and receive the reply from the xBestIndex
** method of an sqlite3_module.  The fields under **Inputs** are the
** inputs to xBestIndex and are read-only.  xBestIndex inserts its

**    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>

}
static int echoCommit(sqlite3_vtab *tab){
  return echoTransactionCall(tab, "xCommit");
}
static int echoRollback(sqlite3_vtab *tab){
  return echoTransactionCall(tab, "xRollback");
}

/*
** Implementation of "GLOB" function on the echo module.  Pass
** all arguments to the ::echo_glob_overload procedure of TCL
** and return the result of that procedure as a string.
*/
static void overloadedGlobFunction(
  sqlite3_context *pContext,
  int nArg,
  sqlite3_value **apArg
){
  Tcl_Interp *interp = sqlite3_user_data(pContext);
  Tcl_DString str;
  int i;
  int rc;
  Tcl_DStringInit(&str);
  Tcl_DStringAppendElement(&str, "::echo_glob_overload");
  for(i=0; i<nArg; i++){
    Tcl_DStringAppendElement(&str, (char*)sqlite3_value_text(apArg[i]));
  }
  rc = Tcl_Eval(interp, Tcl_DStringValue(&str));
  Tcl_DStringFree(&str);
  if( rc ){
    sqlite3_result_error(pContext, Tcl_GetStringResult(interp), -1);
  }else{
    sqlite3_result_text(pContext, Tcl_GetStringResult(interp),
                        -1, SQLITE_TRANSIENT);
  }
  Tcl_ResetResult(interp);
}

/*
** This is the xFindFunction implementation for the echo module.
** SQLite calls this routine when the first argument of a function
** is a column of an echo virtual table.  This routine can optionally
** override the implementation of that function.  It will choose to
** do so if the function is named "glob", and a TCL command named
** ::echo_glob_overload exists.
*/
static int echoFindFunction(
  sqlite3_vtab *vtab,
  int nArg,
  const char *zFuncName,
  void (**pxFunc)(sqlite3_context*,int,sqlite3_value**),
  void **ppArg
){
  echo_vtab *pVtab = (echo_vtab *)vtab;
  Tcl_Interp *interp = pVtab->interp;
  Tcl_CmdInfo info;
  if( strcmp(zFuncName,"glob")!=0 ){
    return 0;
  }
  if( Tcl_GetCommandInfo(interp, "::echo_glob_overload", &info)==0 ){
    return 0;
  }
  *pxFunc = overloadedGlobFunction;
  *ppArg = interp;
  return 1;
}

/*
** A virtual table module that merely "echos" the contents of another
** table (like an SQL VIEW).
*/
static sqlite3_module echoModule = {
  0,                         /* iVersion */

  echoColumn,                /* xColumn - read data */
  echoRowid,                 /* xRowid - read data */
  echoUpdate,                /* xUpdate - write data */
  echoBegin,                 /* xBegin - begin transaction */
  echoSync,                  /* xSync - sync transaction */
  echoCommit,                /* xCommit - commit transaction */
  echoRollback,              /* xRollback - rollback transaction */
  echoFindFunction,          /* xFindFunction - function overloading */
};

/*
** Decode a pointer to an sqlite3 object.
*/
static int getDbPointer(Tcl_Interp *interp, const char *zA, sqlite3 **ppDb){
  *ppDb = (sqlite3*)sqlite3TextToPtr(zA);

/*
** 2006 June 10
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    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 1.27 2006/07/08 18:09:15 drh Exp $
*/
#ifndef SQLITE_OMIT_VIRTUALTABLE
#include "sqliteInt.h"

/*
** External API function used to create a new virtual-table module.
*/

  FuncDef *pDef,  /* Function to possibly overload */
  int nArg,       /* Number of arguments to the function */
  Expr *pExpr     /* First argument to the function */
){
  Table *pTab;
  sqlite3_vtab *pVtab;
  sqlite3_module *pMod;
  void (*xFunc)(sqlite3_context*,int,sqlite3_value**);
  void *pArg;

  int rc;
  FuncDef *pNew;

  /* Check to see the left operand is a column in a virtual table */
  if( pExpr==0 ) return pDef;
  if( pExpr->op!=TK_COLUMN ) return pDef;
  pTab = pExpr->pTab;
  if( pTab==0 ) return pDef;
  if( !pTab->isVirtual ) return pDef;
  pVtab = pTab->pVtab;
  assert( pVtab!=0 );
  assert( pVtab->pModule!=0 );
  pMod = pVtab->pModule;
  if( pMod->xFindFunction==0 ) return pDef;
 
  /* Call the xFuncFunction method on the virtual table implementation
  ** to see if the implementation wants to overload this function */
  if( pMod->xFindFunction(pVtab, nArg, pDef->zName, &xFunc, &pArg)==0 ){
    return pDef;
  }

  /* Create a new ephemeral function definition for the overloaded
  ** function */
  pNew = sqliteMalloc( sizeof(*pNew) + strlen(pDef->zName) );
  if( pNew==0 ){
    return pDef;
  }
  *pNew = *pDef;
  strcpy(pNew->zName, pDef->zName);
  pNew->xFunc = xFunc;
  pNew->pUserData = pArg;

  pNew->flags |= SQLITE_FUNC_EPHEM;
  return pNew;
}

#endif /* SQLITE_OMIT_VIRTUALTABLE */

# 2006 June 10
#
# The author disclaims copyright to this source code.  In place of
# a legal notice, here is a blessing:
#
#    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 implements regression tests for SQLite library.  The
# focus of this file is creating and dropping virtual tables.
#
# $Id: vtab1.test,v 1.34 2006/07/08 18:09:15 drh Exp $

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

ifcapable !vtab||!schema_pragmas {
  finish_test
  return

  }
  set echo_module
} [list \
  xBestIndex {SELECT rowid, * FROM 'r'} \
  xFilter {SELECT rowid, * FROM 'r'}    \
]


# Testing the xFindFunction interface
#
do_test vtab1.11-1 {
  execsql {
    INSERT INTO r(a,b,c) VALUES(1,'?',99);
    INSERT INTO r(a,b,c) VALUES(2,3,99);
    SELECT a GLOB b FROM e
  }
} {1 0}
proc ::echo_glob_overload {a b} {
 return [list $b $a]
}
do_test vtab1.11-2 {
  execsql {
    SELECT a like b FROM e
  }
} {0 0}
do_test vtab1.11-3 {
  execsql {
    SELECT a glob b FROM e
  }
} {{1 ?} {2 3}}


finish_test