<?php

/***********************************************************************

  Copyright (C) 2002-2008  PunBB.org

  This file is part of PunBB.

  PunBB is free software; you can redistribute it and/or modify it

  under the terms of the GNU General Public License as published

  by the Free Software Foundation; either version 2 of the License,

  or (at your option) any later version.

  PunBB 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 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

************************************************************************/

// Make sure we have built in support for MySQL

if (!function_exists('mysql_connect'))

	exit('This PHP environment doesn\'t have MySQL support built in. MySQL support is required if you want to use a MySQL database to run this forum. Consult the PHP documentation for further assistance.');

class DBLayer

{

	var $prefix;

	var $link_id;

	var $query_result;

	var $saved_queries = array();

	var $num_queries = 0;

	function DBLayer($db_host, $db_username, $db_password, $db_name, $db_prefix, $p_connect)

	{

		$this->prefix = $db_prefix;

		if ($p_connect)

			$this->link_id = @mysql_pconnect($db_host, $db_username, $db_password);

		else

			$this->link_id = @mysql_connect($db_host, $db_username, $db_password);

		if ($this->link_id)

		{

			if (@mysql_select_db($db_name, $this->link_id))

				return $this->link_id;

			else

				error('Unable to select database. MySQL reported: '.mysql_error(), __FILE__, __LINE__);

		}

		else

			error('Unable to connect to MySQL server. MySQL reported: '.mysql_error(), __FILE__, __LINE__);

		// Setup the client-server character set (UTF-8)

		if (!defined('PUN_NO_SET_NAMES'))

			mysql_query('SET NAMES \'utf8\'', $this->link_id) or error(__FILE__, __LINE__);

	}

	function start_transaction()

	{

		return;

	}

	function end_transaction()

	{

		return;

	}

	function query($sql, $unbuffered = false)

	{

		if (strlen($sql) > 140000)

			exit('Insane query. Aborting.');

		if (defined('PUN_SHOW_QUERIES'))

			$q_start = get_microtime();

		if ($unbuffered)

			$this->query_result = @mysql_unbuffered_query($sql, $this->link_id);

		else

			$this->query_result = @mysql_query($sql, $this->link_id);

		if ($this->query_result)

		{

			if (defined('PUN_SHOW_QUERIES'))

				$this->saved_queries[] = array($sql, sprintf('%.5f', get_microtime() - $q_start));

			++$this->num_queries;

			return $this->query_result;

		}

		else

		{

			if (defined('PUN_SHOW_QUERIES'))

				$this->saved_queries[] = array($sql, 0);

			return false;

		}

	}

	function query_build($query, $unbuffered = false)

	{

		$sql = '';

		if (isset($query['SELECT']))

		{

			$sql = 'SELECT '.$query['SELECT'].' FROM '.(isset($query['PARAMS']['NO_PREFIX']) ? '' : $this->prefix).$query['FROM'];

			if (isset($query['JOINS']))

			{

				foreach ($query['JOINS'] as $cur_join)

					$sql .= ' '.key($cur_join).' '.(isset($query['PARAMS']['NO_PREFIX']) ? '' : $this->prefix).current($cur_join).' ON '.$cur_join['ON'];

			}

			if (!empty($query['WHERE']))

				$sql .= ' WHERE '.$query['WHERE'];

			if (!empty($query['GROUP BY']))

				$sql .= ' GROUP BY '.$query['GROUP BY'];

			if (!empty($query['HAVING']))

				$sql .= ' HAVING '.$query['HAVING'];

			if (!empty($query['ORDER BY']))

				$sql .= ' ORDER BY '.$query['ORDER BY'];

			if (!empty($query['LIMIT']))

				$sql .= ' LIMIT '.$query['LIMIT'];

		}

		else if (isset($query['INSERT']))

		{

			$sql = 'INSERT INTO '.(isset($query['PARAMS']['NO_PREFIX']) ? '' : $this->prefix).$query['INTO'];

			if (!empty($query['INSERT']))

				$sql .= ' ('.$query['INSERT'].')';

			$sql .= ' VALUES('.$query['VALUES'].')';

		}

		else if (isset($query['UPDATE']))

		{

			$query['UPDATE'] = (isset($query['PARAMS']['NO_PREFIX']) ? '' : $this->prefix).$query['UPDATE'];

			if (isset($query['PARAMS']['LOW_PRIORITY']))

				$query['UPDATE'] = 'LOW_PRIORITY '.$query['UPDATE'];

			$sql = 'UPDATE '.$query['UPDATE'].' SET '.$query['SET'];

			if (!empty($query['WHERE']))

				$sql .= ' WHERE '.$query['WHERE'];

		}

		else if (isset($query['DELETE']))

		{

			$sql = 'DELETE FROM '.(isset($query['PARAMS']['NO_PREFIX']) ? '' : $this->prefix).$query['DELETE'];

			if (!empty($query['WHERE']))

				$sql .= ' WHERE '.$query['WHERE'];

		}

		else if (isset($query['REPLACE']))

		{

			$sql = 'REPLACE INTO '.(isset($query['PARAMS']['NO_PREFIX']) ? '' : $this->prefix).$query['INTO'];

			if (!empty($query['REPLACE']))

				$sql .= ' ('.$query['REPLACE'].')';

			$sql .= ' VALUES('.$query['VALUES'].')';

		}

		return $this->query($sql, $unbuffered);

	}

	function result($query_id = 0, $row = 0)

	{

		return ($query_id) ? @mysql_result($query_id, $row) : false;

	}

	function fetch_assoc($query_id = 0)

	{

		return ($query_id) ? @mysql_fetch_assoc($query_id) : false;

	}

	function fetch_row($query_id = 0)

	{

		return ($query_id) ? @mysql_fetch_row($query_id) : false;

	}

	function num_rows($query_id = 0)

	{

		return ($query_id) ? @mysql_num_rows($query_id) : false;

	}

	function affected_rows()

	{

		return ($this->link_id) ? @mysql_affected_rows($this->link_id) : false;

	}

	function insert_id()

	{

		return ($this->link_id) ? @mysql_insert_id($this->link_id) : false;

	}

	function get_num_queries()

	{

		return $this->num_queries;

	}

	function get_saved_queries()

	{

		return $this->saved_queries;

	}

	function free_result($query_id = false)

	{

		return ($query_id) ? @mysql_free_result($query_id) : false;

	}

	function escape($str)

	{

		if (is_array($str))

			return '';

		else if (function_exists('mysql_real_escape_string'))

			return mysql_real_escape_string($str, $this->link_id);

		else

			return mysql_escape_string($str);

	}

	function error()

	{

		$result['error_sql'] = @current(@end($this->saved_queries));

		$result['error_no'] = @mysql_errno($this->link_id);

		$result['error_msg'] = @mysql_error($this->link_id);

		return $result;

	}

	function close()

	{

		if ($this->link_id)

		{

			if ($this->query_result)

				@mysql_free_result($this->query_result);

			return @mysql_close($this->link_id);

		}

		else

			return false;

	}

	function table_exists($table_name)

	{

		$result = $this->query('SHOW TABLES LIKE \''.$this->escape($table_name).'\'');

		return $this->num_rows($result) > 0;

	}

	function field_exists($table_name, $field_name)

	{

		$result = $this->query('SHOW COLUMNS FROM '.$table_name.' LIKE \''.$this->escape($field_name).'\'');

		return $this->num_rows($result) > 0;

	}

	function index_exists($table_name, $index_name)

	{

		$exists = false;

		$result = $this->query('SHOW INDEX FROM '.$table_name);

		while ($cur_index = $this->fetch_assoc($result))

		{

			if ($cur_index['Key_name'] == $index_name)

			{

				$exists = true;

				break;

			}

		}

		return $exists;

	}

	function add_field($table_name, $field_name, $field_type, $allow_null, $default_value = null, $after_field = null)

	{

		if ($this->field_exists($table_name, $field_name))

			return;

		if ($default_value !== null && !is_int($default_value) && !is_float($default_value))

			$default_value = '\''.$this->escape($default_value).'\'';

		$this->query('ALTER TABLE '.$table_name.' ADD '.$field_name.' '.$field_type.($allow_null ? ' ' : ' NOT NULL').($default_value !== null ? ' DEFAULT '.$default_value : ' ').($after_field != null ? ' AFTER '.$after_field : '')) or error(__FILE__, __LINE__);

	}

	function drop_field($table_name, $field_name)

	{

		if (!$this->field_exists($table_name, $field_name))

			return;

		$this->query('ALTER TABLE '.$table_name.' DROP '.$field_name) or error(__FILE__, __LINE__);

	}

}