SQLite

/*
** 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 1.18 2006/06/17 11:30:32 danielk1977 Exp $
*/
#ifndef SQLITE_OMIT_VIRTUALTABLE
#include "sqliteInt.h"

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

      sqlite3ErrorMsg(pParse, "%s", zErr);
    }
    sqliteFree(zErr);
  }

  return rc;
}

/*
** Add the virtual table pVtab to the array sqlite3.aVTrans[].
*/
int addToVTrans(sqlite3 *db, sqlite3_vtab *pVtab){
  const int ARRAY_INCR = 5;

  /* Grow the sqlite3.aVTrans array if required */
  if( (db->nVTrans%ARRAY_INCR)==0 ){
    sqlite3_vtab **aVTrans;
    int nBytes = sizeof(sqlite3_vtab *) * (db->nVTrans + ARRAY_INCR);
    aVTrans = sqliteRealloc((void *)db->aVTrans, nBytes);
    if( !aVTrans ){
      return SQLITE_NOMEM;
    }
    memset(&aVTrans[db->nVTrans], 0, sizeof(sqlite3_vtab *)*ARRAY_INCR);
    db->aVTrans = aVTrans;
  }

  /* Add pVtab to the end of sqlite3.aVTrans */
  db->aVTrans[db->nVTrans++] = pVtab;
  return SQLITE_OK;
}

/*
** 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.

  */
  if( !pMod ){
    *pzErr = sqlite3MPrintf("no such module: %s", zModule);
    rc = SQLITE_ERROR;
  }else{
    rc = vtabCallConstructor(db, pTab, pMod, pMod->pModule->xCreate, pzErr);
  }

  if( rc==SQLITE_OK && pTab->pVtab ){
    rc = addToVTrans(db, pTab->pVtab);
  }

  return rc;
}

/*
** This function is used to set the schema of a virtual table.  It is only
** valid to call this function from within the xCreate() or xConnect() of a

      pTab->pVtab = 0;
    }
  }

  return rc;
}

void sqlite3VtabCodeLock(Parse *pParse, Table *pTab){
  Vdbe *v = sqlite3GetVdbe(pParse);
  sqlite3VdbeOp3(v, OP_VBegin, 0, 0, (const char*)pTab->pVtab, P3_VTAB);
}

/*
** This function invokes either the xRollback or xCommit method
** of each of the virtual tables in the sqlite3.aVTrans array. The method
** called is identified by the second argument, "offset", which is
** the offset of the method to call in the sqlite3_module structure.
**
** The array is cleared after invoking the callbacks. 
*/
static void callFinaliser(sqlite3 *db, int offset){

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

  }


  sqliteFree(db->aVTrans);
  db->nVTrans = 0;
  db->aVTrans = 0;







}

/*
** If argument rc 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;
  if( rc2!=SQLITE_OK ) return rc2;
  for(i=0; rc==SQLITE_OK && i<db->nVTrans && db->aVTrans[i]; i++){
    sqlite3_vtab *pVtab = db->aVTrans[i];
    int (*x)(sqlite3_vtab *);
    x = pVtab->pModule->xSync;
    if( x ){
      rc = x(pVtab);
    }
  }
  return rc;
}

/*
** Invoke the xRollback method of all virtual tables in the 
** sqlite3.aVTrans array. Then clear the array itself.
*/
int sqlite3VtabRollback(sqlite3 *db){
  callFinaliser(db, (int)(&((sqlite3_module *)0)->xRollback));
  return SQLITE_OK;
}

/*
** Invoke the xCommit method of all virtual tables in the 
** sqlite3.aVTrans array. Then clear the array itself.
*/
int sqlite3VtabCommit(sqlite3 *db){
  callFinaliser(db, (int)(&((sqlite3_module *)0)->xCommit));
  return SQLITE_OK;
}

/*
** If the virtual table pVtab supports the transaction interface
** (xBegin/xRollback/xCommit and optionally xSync) and a transaction is
** not currently open, invoke the xBegin method now.
**
** If the xBegin call is successful, place the sqlite3_vtab pointer
** in the sqlite3.aVTrans array.
*/
int sqlite3VtabBegin(sqlite3 *db, sqlite3_vtab *pVtab){
  int rc = SQLITE_OK;

  const sqlite3_module *pModule = pVtab->pModule;
  if( pModule->xBegin ){
    int i;

    /* If pVtab is already in the aVTrans array, return early */
    for(i=0; (i<db->nVTrans) && 0!=db->aVTrans[i]; i++){
      if( db->aVTrans[i]==pVtab ){
        return SQLITE_OK;
      }
    }

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












    rc = addToVTrans(db, pVtab);


  }
  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 1.21 2006/06/17 11:30:33 danielk1977 Exp $

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

ifcapable !vtab {
  finish_test
  return

  set echo_module ""
  execsql {
    CREATE TABLE treal(a INTEGER, b INTEGER, c); 
    CREATE INDEX treal_idx ON treal(b);
    CREATE VIRTUAL TABLE t1 USING echo(treal);
  }
  set echo_module
} [list xCreate echo treal   \
        xSync   echo(treal)  \
        xCommit echo(treal)  \
]

# Test that a SELECT on t1 doesn't crash. No rows are returned
# because the underlying real table is currently empty.
#
do_test vtab1-3.2 {
  execsql {
    SELECT a, b, c FROM t1;

# 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.
#
# $Id: vtab2.test,v 1.1 2006/06/17 11:30:33 danielk1977 Exp $

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

ifcapable !vtab {
  finish_test
  return
}

register_schema_module [sqlite3_connection_pointer db]
do_test vtab2-1.1 {
  execsql {
    CREATE VIRTUAL TABLE schema USING schema;
    SELECT * FROM schema;
  }
} [list \
  main schema 0 database   {} 0 {} 0 \
  main schema 1 tablename  {} 0 {} 0 \
  main schema 2 cid        {} 0 {} 0 \
  main schema 3 name       {} 0 {} 0 \
  main schema 4 type       {} 0 {} 0 \
  main schema 5 not_null   {} 0 {} 0 \
  main schema 6 dflt_value {} 0 {} 0 \
  main schema 7 pk         {} 0 {} 0 \
]

finish_test