/gmyth-0.7.1/gmyth/gmyth_query.c

/**
 * GMyth Library
 *
 * @file gmyth/gmyth_query.c
 * 
 * @brief <p> GMythQuery class provides a wrapper for accessing
 * the libmysqlclient funtions.
 *
 * Copyright (C) 2006 INdT - Instituto Nokia de Tecnologia.
 * @author Leonardo Sobral Cunha <leonardo.cunha@indt.org.br>
 *
 * 
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <stdlib.h>
#include <stdio.h>
#include <assert.h>

#include "gmyth_query.h"
#include "gmyth_debug.h"

static void     gmyth_query_class_init(GMythQueryClass * klass);
static void     gmyth_query_init(GMythQuery * object);

static void     gmyth_query_dispose(GObject * object);
static void     gmyth_query_finalize(GObject * object);

static void     gmyth_query_print_error(MYSQL * conn, char *message);

G_DEFINE_TYPE(GMythQuery, gmyth_query, G_TYPE_OBJECT)
    static void     gmyth_query_class_init(GMythQueryClass * klass)
{
    GObjectClass   *gobject_class;

    gobject_class = (GObjectClass *) klass;

    gobject_class->dispose = gmyth_query_dispose;
    gobject_class->finalize = gmyth_query_finalize;
}

static void
gmyth_query_init(GMythQuery * gmyth_query)
{
    gmyth_query->backend_info = NULL;

    /*
     * initialize connection handler 
     */
    gmyth_query->conn = mysql_init(NULL);

    if (!(gmyth_query->conn))
        g_warning("[%s] MSQL structure not initialized", __FUNCTION__);
}

static void
gmyth_query_dispose(GObject * object)
{
    GMythQuery     *gmyth_query = GMYTH_QUERY(object);

    if (gmyth_query->conn != NULL) {
        gmyth_query_disconnect(gmyth_query);
    }

    if (gmyth_query->backend_info) {
        g_object_unref(gmyth_query->backend_info);
        gmyth_query->backend_info = NULL;
    }

    G_OBJECT_CLASS(gmyth_query_parent_class)->dispose(object);
}

static void
gmyth_query_finalize(GObject * object)
{
    g_signal_handlers_destroy(object);

    G_OBJECT_CLASS(gmyth_query_parent_class)->finalize(object);
}

/** Creates a new instance of GMythQuery.
 *
 * @return a new instance of GMythQuery.
 */
GMythQuery     *
gmyth_query_new()
{
    GMythQuery     *sql_query =
        GMYTH_QUERY(g_object_new(GMYTH_QUERY_TYPE, NULL));

    return sql_query;
}

gboolean
gmyth_query_connect_with_timeout(GMythQuery * gmyth_query,
                                 GMythBackendInfo * backend_info,
                                 guint timeout)
{
    assert(gmyth_query);

    if (gmyth_query->conn == NULL)
        gmyth_query->conn = mysql_init(NULL);

    if (timeout != 0) {
      /*
       * sets connection timeout
       */
        mysql_options(gmyth_query->conn, MYSQL_OPT_CONNECT_TIMEOUT,
                      (gchar *) & timeout);
    }

    return gmyth_query_connect(gmyth_query, backend_info);
}

/** Connects to the Mysql database in the backend. The backend address
 * is loaded from the GMythBackendInfo instance.
 *
 * @param gmyth_query the GMythEPG instance to be connected.
 * @return true if connection was success, false if failed.
 */
gboolean
gmyth_query_connect(GMythQuery * gmyth_query,
                    GMythBackendInfo * backend_info)
{
    assert(gmyth_query);
    g_return_val_if_fail(backend_info != NULL, FALSE);
    g_return_val_if_fail(backend_info->hostname != NULL, FALSE);
    g_return_val_if_fail(backend_info->username != NULL, FALSE);
    g_return_val_if_fail(backend_info->password != NULL, FALSE);
    g_return_val_if_fail(backend_info->db_name != NULL, FALSE);

    if (gmyth_query->backend_info != NULL) {
        g_object_unref(gmyth_query->backend_info);
    }
    gmyth_query->backend_info = g_object_ref(backend_info);

    if (gmyth_query->conn == NULL) {
        gmyth_query->conn = mysql_init(NULL);
    }

    /*
     * connect to server
     */
    if (mysql_real_connect(gmyth_query->conn,
                           gmyth_query->backend_info->hostname,
                           gmyth_query->backend_info->username,
                           gmyth_query->backend_info->password,
                           gmyth_query->backend_info->db_name, 
                           gmyth_query->backend_info->db_port, 
                           NULL,
                           0) == NULL) {
        gmyth_query_print_error(gmyth_query->conn,
                                "mysql_real_connect() failed");
        return FALSE;
    }

    gmyth_debug
        ("[%s] Connection to Mysql server succeeded! (host = %s, user = %s, "
         "password = %s, db name = %s)", __FUNCTION__,
         gmyth_query->backend_info->hostname,
         gmyth_query->backend_info->username,
         gmyth_query->backend_info->password,
         gmyth_query->backend_info->db_name);

    return TRUE;
}

gboolean
gmyth_query_is_alive (GMythQuery *gmyth_query) 
{
    g_return_val_if_fail (gmyth_query != NULL, FALSE);

    return (mysql_ping (gmyth_query->conn) == 0);
}


/** Disconnects from the Mysql database in the backend.
 * 
 * @param gmyth_query the GMythQuery instance to be disconnected
 * @return true if disconnection was success, false if failed.
 */
gboolean
gmyth_query_disconnect(GMythQuery * gmyth_query)
{
    g_return_val_if_fail(gmyth_query != NULL, FALSE);
    g_return_val_if_fail(gmyth_query->conn != NULL, FALSE);

    /*
     * TODO: Check how to return error 
     */
    gmyth_debug("[%s] Closing gmyth_query->conn", __FUNCTION__);

    mysql_close(gmyth_query->conn);
    gmyth_query->conn = NULL;

    return TRUE;
}

static void
gmyth_query_print_error(MYSQL * conn, char *message)
{
    gmyth_debug("%s", message);

    if (conn != NULL) {
#if MYSQL_VERSION_ID >= 40101
        gmyth_debug("Error %u (%s): %s\n",
                    mysql_errno(conn), mysql_sqlstate(conn),
                    mysql_error(conn));
#else
        gmyth_debug("Error %u: %s\n", mysql_errno(conn),
                    mysql_error(conn));
#endif
    }
}

/** Sends the given query to the backend returning the query result as
 * MYSQL_RES pointer.
 * 
 * FIXME: this function is returning NULL whether any error happens
 * or no rows are returned (e.g. UPDATE or REPLACE).
 * 
 * @param gmyth_query the GMythQuery instance.
 * @param stmt_str the query text.
 * @return the MYSQL_RES result pointer or NULL if any error happens.
 */
MYSQL_RES*
gmyth_query_process_statement(GMythQuery * gmyth_query, char *stmt_str)
{
    assert(gmyth_query);

    gmyth_debug("[%s] Running mysql query %s", __FUNCTION__, stmt_str);

    if (gmyth_query == NULL)
        return NULL;

    //the statement failed
    if (mysql_query(gmyth_query->conn, stmt_str) != 0) {
        gmyth_query_print_error(gmyth_query->conn,
                                "Could not execute statement");
        return NULL;
    }

    //the statement succeeded; determine whether it returned data
    return mysql_store_result(gmyth_query->conn);
}

MYSQL_RES*
gmyth_query_process_statement_with_increment(GMythQuery * gmyth_query,
                                             char *stmt_str, gulong * id)
{
    assert(gmyth_query);

    gmyth_debug("[%s] Running mysql query %s", __FUNCTION__, stmt_str);

    if (gmyth_query == NULL)
        return NULL;

    /*
     * the statement failed
     */
    if (mysql_query(gmyth_query->conn, stmt_str) != 0) {
        gmyth_query_print_error(gmyth_query->conn,
                                "Could not execute statement");
        return NULL;
    }

    *id = (my_ulonglong) mysql_insert_id(gmyth_query->conn);

    /*
     * the statement succeeded; determine whether it returned data 
     */
    return mysql_store_result(gmyth_query->conn);
}