SQLite

**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains the implementation of the sqlite3_prepare()
** interface, and routines that contribute to loading the database schema
** from disk.
**
** $Id: prepare.c,v 1.35 2006/06/12 06:09:18 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>

/*
** Fill the InitData structure with an error message that indicates

** This is the callback routine for the code that initializes the
** database.  See sqlite3Init() below for additional information.
** This routine is also called from the OP_ParseSchema opcode of the VDBE.
**
** Each callback contains the following information:
**
**     argv[0] = name of thing being created
**     argv[1] = root page number for table or index. 0 for trigger or view.
**     argv[2] = SQL text for the CREATE statement.
**     argv[3] = "1" for temporary files, "0" for main database, "2" or more
**               for auxiliary database files.
**
*/
int sqlite3InitCallback(void *pInit, int argc, char **argv, char **azColName){
  InitData *pData = (InitData*)pInit;

/*
** 2001 September 15
**
** 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.
**
*************************************************************************
** Internal interface definitions for SQLite.
**
** @(#) $Id: sqliteInt.h,v 1.498 2006/06/12 06:09:18 danielk1977 Exp $
*/
#ifndef _SQLITEINT_H_
#define _SQLITEINT_H_

/*
** Extra interface definitions for those who need them
*/

#else
   void sqlite3VtabClear(Table*);
#endif
void sqlite3VtabBeginParse(Parse*, Token*, Token*, Token*);
void sqlite3VtabFinishParse(Parse*, Token*);
void sqlite3VtabArgInit(Parse*);
void sqlite3VtabArgExtend(Parse*, Token*);
int sqlite3VtabCallCreate(sqlite3*, int, const char *, char **);

#ifdef SQLITE_SSE
#include "sseInt.h"
#endif

#endif

**    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 1.2 2006/06/12 06:09:19 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include "tcl.h"
#include "os.h"
#include <stdlib.h>
#include <string.h>

/*
** Global Tcl variable $echo_module is a list. This routine appends
** the string element zArg to that list in interpreter interp.
*/
static void appendToEchoModule(const sqlite3_module *pModule, const char *zArg){
  int flags = (TCL_APPEND_VALUE | TCL_LIST_ELEMENT | TCL_GLOBAL_ONLY);
  Tcl_SetVar((Tcl_Interp *)(pModule->pAux), "echo_module", zArg, flags);
}

/* Methods for the echo module */
static int echoCreate(
  sqlite3 *db,
  const sqlite3_module *pModule,
  int argc, char **argv,
  sqlite3_vtab **ppVtab
){
  int i;
  Tcl_Interp *interp = pModule->pAux;
  *ppVtab = pModule->pAux;

  appendToEchoModule(pModule, "xCreate");
  for(i=0; i<argc; i++){
    appendToEchoModule(pModule, argv[i]);

  }

  return 0;
}
static int echoConnect(
  sqlite3 *db,
  const sqlite3_module *pModule,
  int argc, char **argv,
  sqlite3_vtab **ppVtab

}

/*
** A virtual table module that merely echos method calls into TCL
** variables.
*/
static sqlite3_module echoModule = {
  0,                         /* iVersion */
  "echo",                    /* zName */
  0,                         /* pAux */
  echoCreate,
  echoConnect,
  0,                         /* xBestIndex */
  echoDisconnect, 
  echoDestroy,
};

/*
** Decode a pointer to an sqlite3 object.
*/

**
** 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 1.552 2006/06/12 06:09:19 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>
#include "vdbeInt.h"

/*

    sqlite3SetString(&p->zErrMsg, "database table is locked: ", z, (char*)0);
  }
  break;
}
#endif /* SQLITE_OMIT_SHARED_CACHE */

#ifndef SQLITE_OMIT_VIRTUALTABLE
/* Opcode: VCreate P1 * P3
**
** P3 is the name of a virtual table in database P1. Call the xCreate method
** for that table.
*/
case OP_VCreate: {
  rc = sqlite3VtabCallCreate(db, pOp->p1, pOp->p3, &p->zErrMsg);
  break;
}
#endif /* SQLITE_OMIT_VIRTUALTABLE */

#ifndef SQLITE_OMIT_VIRTUALTABLE
/* Opcode: VDestroy * * P3
**
** P3 is the name of a virtual table.  Call the xDestroy method for
** that table.
*/
case OP_VDestroy: {
  break;
}
#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 contains code used to help implement virtual tables.
**
** $Id: vtab.c,v 1.2 2006/06/12 06:09:19 danielk1977 Exp $
*/
#ifndef SQLITE_OMIT_VIRTUALTABLE
#include "sqliteInt.h"

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

  Parse *pParse,        /* Parsing context */
  Token *pName1,        /* Name of new table, or database name */
  Token *pName2,        /* Name of new table or NULL */
  Token *pModuleName    /* Name of the module for the virtual table */
){
  Table *pTable;        /* The new virtual table */

  /* TODO: The 5th argument to sqlite3StartTable() - isView - is being 
  ** passed a true value at present. This prevents sqlite3StartTable()
  ** from coding OP_CreateTable, which is correct, but causes it
  ** to invoke the authorization function as if a CREATE VIEW statement
  ** were attempted, which is incorrect.
  */
  sqlite3StartTable(pParse, pName1, pName2, 0, 1, 0);

  pTable = pParse->pNewTable;
  if( pTable==0 ) return;
  pTable->isVirtual = 1;
  pTable->nModuleArg = 0;
  addModuleArgument(pTable, sqlite3NameFromToken(pModuleName));
  pParse->sNameToken.n = pModuleName->z + pModuleName->n - pName1->z;
}

  ** 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, "unknown 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;
    }
    zStmt = sqlite3MPrintf("CREATE VIRTUAL TABLE %T", &pParse->sNameToken);

    /* A slot for the record has already been allocated in the 
    ** SQLITE_MASTER table.  We just need to update that slot with all
    ** the information we've collected.  
    **
    ** The top of the stack is the rootpage allocated by sqlite3StartTable().
    ** This value is always 0 and is ignored, a virtual table does not have a
    ** rootpage. The next entry on the stack is the rowid of the record
    ** in the sqlite_master table.
    */
    iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
    sqlite3NestedParse(pParse,
      "UPDATE %Q.%s "
         "SET type='table', name=%Q, tbl_name=%Q, rootpage=0, sql=%Q "
       "WHERE rowid=#1",
      db->aDb[iDb].zName, SCHEMA_TABLE(iDb),
      pTab->zName,
      pTab->zName,
      zStmt
    );
    sqliteFree(zStmt);
    v = sqlite3GetVdbe(pParse);

    sqlite3ChangeCookie(db, v, iDb);

    sqlite3VdbeAddOp(v, OP_Expire, 0, 0);
    zWhere = sqlite3MPrintf("name='%q'", pTab->zName);
    sqlite3VdbeOp3(v, OP_ParseSchema, iDb, 0, zWhere, P3_DYNAMIC);
    sqlite3VdbeOp3(v, OP_VCreate, iDb, 0, pTab->zName, strlen(pTab->zName) + 1);
  }

  /* If we are rereading the sqlite_master table create the in-memory
  ** record of the table. 
  **
  ** TODO: If the module is already registered, should we call xConnect()
  ** here, or should it wait until the table is first referenced. Maybe
  ** it's better to be lazy here, in case xConnect() is expensive to call.
  */
  else {
#if 0
    sqlite3_module *pMod = pTab->pModule;
    assert( pMod->xConnect );
    pMod->xConnect(db, pMod, pTab->nModuleArg, pTab->azModuleArg, &pTab->pVtab);
#endif
    Table *pOld;
    Schema *pSchema = pTab->pSchema;
    const char *zName = pTab->zName;
    int nName = strlen(zName) + 1;
    pOld = sqlite3HashInsert(&pSchema->tblHash, zName, nName, pTab);
    if( pOld ){
      assert( pTab==pOld );  /* Malloc must have failed inside HashInsert() */
      return;
    }
  }
}

/*
** The parser calls this routine when it sees the first token
** of an argument to the module name in a CREATE VIRTUAL TABLE statement.
*/

  if( pParse->nArgUsed ){
    pParse->zArg[pParse->nArgUsed++] = ' ';
  }
  memcpy(&pParse->zArg[pParse->nArgUsed], p->z, p->n);
  pParse->nArgUsed += p->n;
  pParse->zArg[pParse->nArgUsed] = 0;
}

/*
** This function is invoked by the vdbe to call the xCreate method
** of the virtual table named zTab in database iDb. 
**
** 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;

  pTab = sqlite3FindTable(db, zTab, db->aDb[iDb].zName);
  assert(pTab && pTab->isVirtual);
  pModule = pTab->pModule;
  const char *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("unknown module: %s", zModule);
    rc = SQLITE_ERROR;
  }else if( pModule->xCreate ){
    /* TODO: Maybe the above condition should refer to pTable->needCreate. */
    char **azArg = pTab->azModuleArg;
    int nArg = pTab->nModuleArg;
    rc = pModule->xCreate(db, pModule, nArg, azArg, &pTab->pVtab);
  }

  if( SQLITE_OK==rc ){
    pTab->needCreate = 0;
  }
  return rc;
}

#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 1.2 2006/06/12 06:09:19 danielk1977 Exp $

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

# We cannot create a virtual table if the module has not
# been registered.
#

} {}

# After we register the echo module, we are allowed to create
# virtual tables using that module.
#
do_test vtab1-1.3 {
  register_echo_module [sqlite3_connection_pointer db]

  catchsql {
    CREATE VIRTUAL TABLE t1 USING echo;
  }
} {0 {}}
do_test vtab1-1.4 {
  set echo_module
} {xCreate echo}
do_test vtab1-1.5 {
  execsql {
    SELECT name, sql FROM sqlite_master ORDER BY 1
  }
} {t1 {CREATE VIRTUAL TABLE t1 USING echo}}


finish_test