Geografic-Information-System/db/drivers/ogr/cursor.c

/*!
  \file db/drivers/cursor.c
  
  \brief Low level OGR SQL driver
 
  (C) 2004-2009 by the GRASS Development Team
  This program is free software under the GNU General Public License
  (>=v2). Read the file COPYING that comes with GRASS for details.
  
  \author Radim Blazek
  \author Some updates by Martin Landa <landa.martin gmail.com>
*/

#include <stdio.h>

#include <grass/gis.h>
#include <grass/dbmi.h>
#include <grass/glocale.h>

#include <ogr_api.h>

#include "globals.h"
#include "proto.h"

/*!
  \brief Close cursor

  \param dbc pointer to dbCursor to be closed

  \return DB_OK on success
  \return DB_FAILED on failure
*/
int db__driver_close_cursor(dbCursor * dbc)
{
    cursor *c;

    G_debug(3, "db_driver_close_cursor()");
    
    /* get my cursor via the dbc token */
    c = (cursor *) db_find_token(db_get_cursor_token(dbc));
    if (c == NULL)
	return DB_FAILED;
    
    /* free_cursor(cursor) */
    free_cursor(c);
    
    G_debug(3, "Cursor closed");

    return DB_OK;
}

/*!
  \brief Allocate cursor

  \return pointer to cursor structure
  \return NULL on error
*/
cursor *alloc_cursor()
{
    cursor *c;

    /* allocate the cursor */
    c = (cursor *) db_malloc(sizeof(cursor));
    if (c == NULL) {
	db_d_append_error(_("Unable to allocate cursor"));
	return NULL;
    }

    G_zero(c, sizeof(cursor));
    
    /* tokenize it */
    c->token = db_new_token(c);
    if (c->token < 0) {
	db_d_append_error(_("Unable to add new token"));
	return NULL;
    }
    return c;
}

/*!
  \brief Free cursor structure (destroy OGR feature and release OGR layer)

  \param c pointer to cursor
*/
void free_cursor(cursor * c)
{
    if (c->hFeature)
	OGR_F_Destroy(c->hFeature);

    if (c->hLayer)
	OGR_DS_ReleaseResultSet(hDs, c->hLayer);

    G_free(c->cols);
    G_free(c);

    db_drop_token(c->token);
}