<?php
/**
*
* @package dbal
* @version $Id$
* @copyright (c) 2005 phpBB Group
* @license http://opensource.org/licenses/gpl-license.php GNU Public License
*
*/

/**
* @ignore
*/
if (!defined('IN_PHPBB'))
{
	exit;
}

/**
* Database Abstraction Layer
* @package dbal
*/
class dbal
{
	var $db_connect_id;
	var $query_result;
	var $return_on_error = false;
	var $transaction = false;
	var $sql_time = 0;
	var $num_queries = array();
	var $open_queries = array();

	var $curtime = 0;
	var $query_hold = '';
	var $html_hold = '';
	var $sql_report = '';
	
	var $persistency = false;
	var $user = '';
	var $server = '';
	var $dbname = '';

	// Set to true if error triggered
	var $sql_error_triggered = false;

	// Holding the last sql query on sql error
	var $sql_error_sql = '';

	// Holding transaction count
	var $transactions = 0;

	// Supports multi inserts?
	var $multi_insert = false;

	// Supports COUNT(DISTINCT ...)?
	var $count_distinct = true;

	// Supports multiple table deletion
	var $multi_table_deletion = false;

	// Supports table truncation
	var $truncate = true;

	/**
	* Current sql layer
	*/
	var $sql_layer = '';

	/**
	* Wildcards for matching any (%) or exactly one (_) character within LIKE expressions
	*/
	var $any_char;
	var $one_char;

	/**
	* Constructor
	*/
	function __construct()
	{
		$this->num_queries = array(
			'cached'		=> 0,
			'normal'		=> 0,
			'total'			=> 0,
		);

		// Fill default sql layer based on the class being called.
		// This can be changed by the specified layer itself later if needed.
		$this->sql_layer = substr(get_class($this), 5);

		// Do not change this please! This variable is used to easy the use of it - and is hardcoded.
		$this->any_char = chr(0) . '%';
		$this->one_char = chr(0) . '_';
	}

	/**
	* return on error or display error message
	*/
	function sql_return_on_error($fail = false)
	{
		$this->sql_error_triggered = false;
		$this->sql_error_sql = '';

		$this->return_on_error = $fail;
	}

	/**
	* Return number of sql queries and cached sql queries used
	*/
	function sql_num_queries($cached = false)
	{
		return ($cached) ? $this->num_queries['cached'] : $this->num_queries['normal'];
	}

	/**
	* Add to query count
	*/
	function sql_add_num_queries($cached = false)
	{
		$this->num_queries['cached'] += ($cached !== false) ? 1 : 0;
		$this->num_queries['normal'] += ($cached !== false) ? 0 : 1;
		$this->num_queries['total'] += 1;
	}

	/**
	* DBAL garbage collection, close sql connection
	*/
	function sql_close()
	{
		if (!$this->db_connect_id)
		{
			return false;
		}

		if ($this->transaction)
		{
			do
			{
				$this->sql_transaction('commit');
			}
			while ($this->transaction);
		}

		foreach ($this->open_queries as $query_id)
		{
			$this->sql_freeresult($query_id);
		}
		
		return $this->_sql_close();
	}

	/**
	* Build LIMIT query
	* Doing some validation here.
	*/
	function sql_query_limit($query, $total, $offset = 0, $cache_ttl = 0)
	{
		if (empty($query))
		{
			return false;
		}

		// Never use a negative total or offset
		$total = ($total < 0) ? 0 : $total;
		$offset = ($offset < 0) ? 0 : $offset;

		return $this->_sql_query_limit($query, $total, $offset, $cache_ttl);
	}

	/**
	* Fetch all rows
	*/
	function sql_fetchrowset($query_id = false)
	{
		if ($query_id === false)
		{
			$query_id = $this->query_result;
		}

		if ($query_id !== false)
		{
			$result = array();
			while ($row = $this->sql_fetchrow($query_id))
			{
				$result[] = $row;
			}

			return $result;
		}
		
		return false;
	}

	/**
	* Fetch field
	* if rownum is false, the current row is used, else it is pointing to the row (zero-based)
	*/
	function sql_fetchfield($field, $rownum = false, $query_id = false)
	{
		global $cache;

		if ($query_id === false)
		{
			$query_id = $this->query_result;
		}

		if ($query_id !== false)
		{
			if ($rownum !== false)
			{
				$this->sql_rowseek($rownum, $query_id);
			}

			if (!is_object($query_id) && isset($cache->sql_rowset[$query_id]))
			{
				return $cache->sql_fetchfield($query_id, $field);
			}

			$row = $this->sql_fetchrow($query_id);
			return (isset($row[$field])) ? $row[$field] : false;
		}

		return false;
	}

	/**
	* Correctly adjust LIKE expression for special characters
	* Some DBMS are handling them in a different way
	*
	* @param string $expression The expression to use. Every wildcard is escaped, except $this->any_char and $this->one_char
	* @return string LIKE expression including the keyword!
	*/
	function sql_like_expression($expression)
	{
		$expression = str_replace(array('_', '%'), array("\_", "\%"), $expression);
		$expression = str_replace(array(chr(0) . "\_", chr(0) . "\%"), array('_', '%'), $expression);

		return $this->_sql_like_expression('LIKE \'' . $this->sql_escape($expression) . '\'');
	}

	/**
	* SQL Transaction
	* @access private
	*/
	function sql_transaction($status = 'begin')
	{
		switch ($status)
		{
			case 'begin':
				// If we are within a transaction we will not open another one, but enclose the current one to not loose data (prevening auto commit)
				if ($this->transaction)
				{
					$this->transactions++;
					return true;
				}

				$result = $this->_sql_transaction('begin');

				if (!$result)
				{
					$this->sql_error();
				}

				$this->transaction = true;
			break;

			case 'commit':
				// If there was a previously opened transaction we do not commit yet... but count back the number of inner transactions
				if ($this->transaction && $this->transactions)
				{
					$this->transactions--;
					return true;
				}

				// Check if there is a transaction (no transaction can happen if there was an error, with a combined rollback and error returning enabled)
				// This implies we have transaction always set for autocommit db's
				if (!$this->transaction)
				{
					return false;
				}

				$result = $this->_sql_transaction('commit');

				if (!$result)
				{
					$this->sql_error();
				}

				$this->transaction = false;
				$this->transactions = 0;
			break;

			case 'rollback':
				$result = $this->_sql_transaction('rollback');
				$this->transaction = false;
				$this->transactions = 0;
			break;

			default:
				$result = $this->_sql_transaction($status);
			break;
		}

		return $result;
	}

	/**
	* Build sql statement from array for insert/update/select statements
	*
	* Idea for this from Ikonboard
	* Possible query values: INSERT, INSERT_SELECT, MULTI_INSERT, UPDATE, SELECT
	*
	*/
	function sql_build_array($query, $assoc_ary = false)
	{
		if (!is_array($assoc_ary))
		{
			return false;
		}

		$fields = $values = array();

		if ($query == 'INSERT' || $query == 'INSERT_SELECT')
		{
			foreach ($assoc_ary as $key => $var)
			{
				$fields[] = $key;

				if (is_array($var) && is_string($var[0]))
				{
					// This is used for INSERT_SELECT(s)
					$values[] = $var[0];
				}
				else
				{
					$values[] = $this->_sql_validate_value($var);
				}
			}

			$query = ($query == 'INSERT') ? ' (' . implode(', ', $fields) . ') VALUES (' . implode(', ', $values) . ')' : ' (' . implode(', ', $fields) . ') SELECT ' . implode(', ', $values) . ' ';
		}
		else if ($query == 'MULTI_INSERT')
		{
			$ary = array();
			foreach ($assoc_ary as $id => $sql_ary)
			{
				// If by accident the sql array is only one-dimensional we build a normal insert statement
				if (!is_array($sql_ary))
				{
					return $this->sql_build_array('INSERT', $assoc_ary);
				}

				$values = array();
				foreach ($sql_ary as $key => $var)
				{
					$values[] = $this->_sql_validate_value($var);
				}
				$ary[] = '(' . implode(', ', $values) . ')';
			}

			$query = ' (' . implode(', ', array_keys($assoc_ary[0])) . ') VALUES ' . implode(', ', $ary);
		}
		else if ($query == 'UPDATE' || $query == 'SELECT')
		{
			$values = array();
			foreach ($assoc_ary as $key => $var)
			{
				$values[] = "$key = " . $this->_sql_validate_value($var);
			}
			$query = implode(($query == 'UPDATE') ? ', ' : ' AND ', $values);
		}

		return $query;
	}

	/**
	* Build IN or NOT IN sql comparison string, uses <> or = on single element
	* arrays to improve comparison speed
	*
	* @access public
	* @param	string	$field				name of the sql column that shall be compared
	* @param	array	$array				array of values that are allowed (IN) or not allowed (NOT IN)
	* @param	bool	$negate				true for NOT IN (), false for IN () (default)
	* @param	bool	$allow_empty_set	If true, allow $array to be empty, this function will return 1=1 or 1=0 then. Default to false.
	*/
	function sql_in_set($field, $array, $negate = false, $allow_empty_set = false)
	{
		if (!sizeof($array))
		{
			if (!$allow_empty_set)
			{
				// Print the backtrace to help identifying the location of the problematic code
				$this->sql_error('No values specified for SQL IN comparison');
			}
			else
			{
				// NOT IN () actually means everything so use a tautology
				if ($negate)
				{
					return '1=1';
				}
				// IN () actually means nothing so use a contradiction
				else
				{
					return '1=0';
				}
			}
		}

		if (!is_array($array))
		{
			$array = array($array);
		}

		if (sizeof($array) == 1)
		{
			@reset($array);
			$var = current($array);

			return $field . ($negate ? ' <> ' : ' = ') . $this->_sql_validate_value($var);
		}
		else
		{
			return $field . ($negate ? ' NOT IN ' : ' IN ') . '(' . implode(', ', array_map(array($this, '_sql_validate_value'), $array)) . ')';
		}
	}

	/**
	* Run more than one insert statement.
	*
	* @param string $table table name to run the statements on
	* @param array &$sql_ary multi-dimensional array holding the statement data.
	*
	* @return bool false if no statements were executed.
	* @access public
	*/
	function sql_multi_insert($table, &$sql_ary)
	{
		if (!sizeof($sql_ary))
		{
			return false;
		}

		if ($this->multi_insert)
		{
			$this->sql_query('INSERT INTO ' . $table . ' ' . $this->sql_build_array('MULTI_INSERT', $sql_ary));
		}
		else
		{
			foreach ($sql_ary as $ary)
			{
				if (!is_array($ary))
				{
					return false;
				}

				$this->sql_query('INSERT INTO ' . $table . ' ' . $this->sql_build_array('INSERT', $ary));
			}
		}

		return true;
	}

	/**
	* Function for validating values
	* @access private
	*/
	function _sql_validate_value($var)
	{
		if (is_null($var))
		{
			return 'NULL';
		}
		else if (is_string($var))
		{
			return "'" . $this->sql_escape($var) . "'";
		}
		else
		{
			return (is_bool($var)) ? intval($var) : $var;
		}
	}

	/**
	* Build sql statement from array for select and select distinct statements
	*
	* Possible query values: SELECT, SELECT_DISTINCT
	*/
	function sql_build_query($query, $array)
	{
		$sql = '';
		switch ($query)
		{
			case 'SELECT':
			case 'SELECT_DISTINCT';

				$sql = str_replace('_', ' ', $query) . ' ' . $array['SELECT'] . ' FROM ';

				$table_array = array();
				foreach ($array['FROM'] as $table_name => $alias)
				{
					if (is_array($alias))
					{
						foreach ($alias as $multi_alias)
						{
							$table_array[] = $table_name . ' ' . $multi_alias;
						}
					}
					else
					{
						$table_array[] = $table_name . ' ' . $alias;
					}
				}

				$sql .= $this->_sql_custom_build('FROM', implode(', ', $table_array));

				if (!empty($array['LEFT_JOIN']))
				{
					foreach ($array['LEFT_JOIN'] as $join)
					{
						$sql .= ' LEFT JOIN ' . key($join['FROM']) . ' ' . current($join['FROM']) . ' ON (' . $join['ON'] . ')';
					}
				}

				if (!empty($array['WHERE']))
				{
					$sql .= ' WHERE ' . $this->_sql_custom_build('WHERE', $array['WHERE']);
				}

				if (!empty($array['GROUP_BY']))
				{
					$sql .= ' GROUP BY ' . $array['GROUP_BY'];
				}

				if (!empty($array['ORDER_BY']))
				{
					$sql .= ' ORDER BY ' . $array['ORDER_BY'];
				}

			break;
		}

		return $sql;
	}

	/**
	* display sql error page
	*/
	function sql_error($sql = '')
	{
		global $auth, $user, $config;

		// Set var to retrieve errored status
		$this->sql_error_triggered = true;
		$this->sql_error_sql = $sql;

		$error = $this->_sql_error();

		if (!$this->return_on_error)
		{
			$message = 'SQL ERROR [ ' . $this->sql_layer . ' ]<br /><br />' . $error['message'] . ' [' . $error['code'] . ']';

			// Show complete SQL error and path to administrators only
			// Additionally show complete error on installation or if extended debug mode is enabled
			// The DEBUG_EXTRA constant is for development only!
			if ((isset($auth) && $auth->acl_get('a_')) || defined('IN_INSTALL') || defined('DEBUG_EXTRA'))
			{
				// Print out a nice backtrace...
				$backtrace = get_backtrace();

				$message .= ($sql) ? '<br /><br />SQL<br /><br />' . htmlspecialchars($sql) : '';
				$message .= ($backtrace) ? '<br /><br />BACKTRACE<br />' . $backtrace : '';
				$message .= '<br />';
			}
			else
			{
				// If error occurs in initiating the session we need to use a pre-defined language string
				// This could happen if the connection could not be established for example (then we are not able to grab the default language)
				if (!isset($user->lang['SQL_ERROR_OCCURRED']))
				{
					$message .= '<br /><br />An sql error occurred while fetching this page. Please contact an administrator if this problem persists.';
				}
				else
				{
					if (!empty($config['board_contact']))
					{
						$message .= '<br /><br />' . sprintf($user->lang['SQL_ERROR_OCCURRED'], '<a href="mailto:' . htmlspecialchars($config['board_contact']) . '">', '</a>');
					}
					else
					{
						$message .= '<br /><br />' . sprintf($user->lang['SQL_ERROR_OCCURRED'], '', '');
					}
				}
			}

			if ($this->transaction)
			{
				$this->sql_transaction('rollback');
			}

			if (strlen($message) > 1024)
			{
				// We need to define $msg_long_text here to circumvent text stripping.
				global $msg_long_text;
				$msg_long_text = $message;

				trigger_error(false, E_USER_ERROR);
			}

			trigger_error($message, E_USER_ERROR);
		}

		if ($this->transaction)
		{
			$this->sql_transaction('rollback');
		}

		return $error;
	}

	/**
	* Explain queries
	*/
	function sql_report($mode, $query = '')
	{
		global $cache, $starttime, $phpbb_root_path, $user;

		if (empty($_REQUEST['explain']))
		{
			return false;
		}

		if (!$query && $this->query_hold != '')
		{
			$query = $this->query_hold;
		}

		switch ($mode)
		{
			case 'display':
				if (!empty($cache))
				{
					$cache->unload();
				}
				$this->sql_close();

				$mtime = explode(' ', microtime());
				$totaltime = $mtime[0] + $mtime[1] - $starttime;

				echo '<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
					<html xmlns="http://www.w3.org/1999/xhtml" dir="ltr">
					<head>
						<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
						<meta http-equiv="Content-Style-Type" content="text/css" />
						<meta http-equiv="imagetoolbar" content="no" />
						<title>SQL Report</title>
						<link href="' . $phpbb_root_path . 'adm/style/admin.css" rel="stylesheet" type="text/css" media="screen" />
					</head>
					<body id="errorpage">
					<div id="wrap">
						<div id="page-header">
							<a href="' . build_url('explain') . '">Return to previous page</a>
						</div>
						<div id="page-body">
							<div id="acp">
							<div class="panel">
								<span class="corners-top"><span></span></span>
								<div id="content">
									<h1>SQL Report</h1>
									<br />
									<p><b>Page generated in ' . round($totaltime, 4) . " seconds with {$this->num_queries['normal']} queries" . (($this->num_queries['cached']) ? " + {$this->num_queries['cached']} " . (($this->num_queries['cached'] == 1) ? 'query' : 'queries') . ' returning data from cache' : '') . '</b></p>

									<p>Time spent on ' . $this->sql_layer . ' queries: <b>' . round($this->sql_time, 5) . 's</b> | Time spent on PHP: <b>' . round($totaltime - $this->sql_time, 5) . 's</b></p>

									<br /><br />
									' . $this->sql_report . '
								</div>
								<span class="corners-bottom"><span></span></span>
							</div>
							</div>
						</div>
						<div id="page-footer">
							Powered by phpBB &copy; 2000, 2002, 2005, 2007 <a href="http://www.phpbb.com/">phpBB Group</a>
						</div>
					</div>
					</body>
					</html>';

				exit_handler();

			break;

			case 'stop':
				$endtime = explode(' ', microtime());
				$endtime = $endtime[0] + $endtime[1];

				$this->sql_report .= '

					<table cellspacing="1">
					<thead>
					<tr>
						<th>Query #' . $this->num_queries['total'] . '</th>
					</tr>
					</thead>
					<tbody>
					<tr>
						<td class="row3"><textarea style="font-family:\'Courier New\',monospace;width:99%" rows="5" cols="10">' . preg_replace('/\t(AND|OR)(\W)/', "\$1\$2", htmlspecialchars(preg_replace('/[\s]*[\n\r\t]+[\n\r\s\t]*/', "\n", $query))) . '</textarea></td>
					</tr>
					</tbody>
					</table>
					
					' . $this->html_hold . '

					<p style="text-align: center;">
				';

				if ($this->query_result)
				{
					if (preg_match('/^(UPDATE|DELETE|REPLACE)/', $query))
					{
						$this->sql_report .= 'Affected rows: <b>' . $this->sql_affectedrows($this->query_result) . '</b> | ';
					}
					$this->sql_report .= 'Before: ' . sprintf('%.5f', $this->curtime - $starttime) . 's | After: ' . sprintf('%.5f', $endtime - $starttime) . 's | Elapsed: <b>' . sprintf('%.5f', $endtime - $this->curtime) . 's</b>';
				}
				else
				{
					$error = $this->sql_error();
					$this->sql_report .= '<b style="color: red">FAILED</b> - ' . $this->sql_layer . ' Error ' . $error['code'] . ': ' . htmlspecialchars($error['message']);
				}

				$this->sql_report .= '</p><br /><br />';

				$this->sql_time += $endtime - $this->curtime;
			break;

			case 'start':
				$this->query_hold = $query;
				$this->html_hold = '';
			
				$this->_sql_report($mode, $query);

				$this->curtime = explode(' ', microtime());
				$this->curtime = $this->curtime[0] + $this->curtime[1];

			break;
			
			case 'add_select_row':

				$html_table = func_get_arg(2);
				$row = func_get_arg(3);
				
				if (!$html_table && sizeof($row))
				{
					$html_table = true;
					$this->html_hold .= '<table cellspacing="1"><tr>';
								
					foreach (array_keys($row) as $val)
					{
						$this->html_hold .= '<th>' . (($val) ? ucwords(str_replace('_', ' ', $val)) : '&nbsp;') . '</th>';
					}
					$this->html_hold .= '</tr>';
				}
				$this->html_hold .= '<tr>';

				$class = 'row1';
				foreach (array_values($row) as $val)
				{
					$class = ($class == 'row1') ? 'row2' : 'row1';
					$this->html_hold .= '<td class="' . $class . '">' . (($val) ? $val : '&nbsp;') . '</td>';
				}
				$this->html_hold .= '</tr>';
			
				return $html_table;

			break;

			case 'fromcache':

				$this->_sql_report($mode, $query);

			break;

			case 'record_fromcache':

				$endtime = func_get_arg(2);
				$splittime = func_get_arg(3);

				$time_cache = $endtime - $this->curtime;
				$time_db = $splittime - $endtime;
				$color = ($time_db > $time_cache) ? 'green' : 'red';

				$this->sql_report .= '<table cellspacing="1"><thead><tr><th>Query results obtained from the cache</th></tr></thead><tbody><tr>';
				$this->sql_report .= '<td class="row3"><textarea style="font-family:\'Courier New\',monospace;width:99%" rows="5" cols="10">' . preg_replace('/\t(AND|OR)(\W)/', "\$1\$2", htmlspecialchars(preg_replace('/[\s]*[\n\r\t]+[\n\r\s\t]*/', "\n", $query))) . '</textarea></td></tr></tbody></table>';
				$this->sql_report .= '<p style="text-align: center;">';
				$this->sql_report .= 'Before: ' . sprintf('%.5f', $this->curtime - $starttime) . 's | After: ' . sprintf('%.5f', $endtime - $starttime) . 's | Elapsed [cache]: <b style="color: ' . $color . '">' . sprintf('%.5f', ($time_cache)) . 's</b> | Elapsed [db]: <b>' . sprintf('%.5f', $time_db) . 's</b></p><br /><br />';

				// Pad the start time to not interfere with page timing
				$starttime += $time_db;

			break;

			default:
			
				$this->_sql_report($mode, $query);

			break;
		}

		return true;
	}
}

/**
* This variable holds the class name to use later
*/
$sql_db = (!empty($dbms)) ? 'dbal_' . basename($dbms) : 'dbal';

?>