database.php

Joomla!是一套获得过多个奖项的内容管理系统(Content Management System, CMS)。Joomla!采用PHP+MySQL数据库开发

<?php
/**
* @version		$Id: database.php 11137 2008-10-15 19:47:01Z kdevine $
* @package		Joomla.Framework
* @subpackage	Database
* @copyright	Copyright (C) 2005 - 2008 Open Source Matters. All rights reserved.
* @license		GNU/GPL, see LICENSE.php
* Joomla! is free software. This version may have been modified pursuant
* to the GNU General Public License, and as distributed it includes or
* is derivative of works licensed under the GNU General Public License or
* other free or open source software licenses.
* See COPYRIGHT.php for copyright notices and details.
*/

// Check to ensure this file is within the rest of the framework
defined('JPATH_BASE') or die();

/**
 * Database connector class
 *
 * @abstract
 * @package		Joomla.Framework
 * @subpackage	Database
 * @since		1.0
 */
class JDatabase extends JObject
{
	/**
	 * The database driver name
	 *
	 * @var string
	 */
	var $name			= '';

	/**
	 * The query sql string
	 *
	 * @var string
	 **/
	var $_sql			= '';

	/**
	 * The database error number
	 *
	 * @var int
	 **/
	var $_errorNum		= 0;

	/**
	 * The database error message
	 *
	 * @var string
	 */
	var $_errorMsg		= '';

	/**
	 * The prefix used on all database tables
	 *
	 * @var string
	 */
	var $_table_prefix	= '';

	/**
	 * The connector resource
	 *
	 * @var resource
	 */
	var $_resource		= '';

	/**
	 * The last query cursor
	 *
	 * @var resource
	 */
	var $_cursor		= null;

	/**
	 * Debug option
	 *
	 * @var boolean
	 */
	var $_debug			= 0;

	/**
	 * The limit for the query
	 *
	 * @var int
	 */
	var $_limit			= 0;

	/**
	 * The for offset for the limit
	 *
	 * @var int
	 */
	var $_offset		= 0;

	/**
	 * The number of queries performed by the object instance
	 *
	 * @var int
	 */
	var $_ticker		= 0;

	/**
	 * A log of queries
	 *
	 * @var array
	 */
	var $_log			= null;

	/**
	 * The null/zero date string
	 *
	 * @var string
	 */
	var $_nullDate		= null;

	/**
	 * Quote for named objects
	 *
	 * @var string
	 */
	var $_nameQuote		= null;

	/**
	 * UTF-8 support
	 *
	 * @var boolean
	 * @since	1.5
	 */
	var $_utf			= 0;

	/**
	 * The fields that are to be quote
	 *
	 * @var array
	 * @since	1.5
	 */
	var $_quoted	= null;

	/**
	 *  Legacy compatibility
	 *
	 * @var bool
	 * @since	1.5
	 */
	var $_hasQuoted	= null;

	/**
	* Database object constructor
	*
	* @access	public
	* @param	array	List of options used to configure the connection
	* @since	1.5
	*/
	function __construct( $options )
	{
		$prefix		= array_key_exists('prefix', $options)	? $options['prefix']	: 'jos_';

		// Determine utf-8 support
		$this->_utf = $this->hasUTF();

		//Set charactersets (needed for MySQL 4.1.2+)
		if ($this->_utf){
			$this->setUTF();
		}

		$this->_table_prefix	= $prefix;
		$this->_ticker			= 0;
		$this->_errorNum		= 0;
		$this->_log				= array();
		$this->_quoted			= array();
		$this->_hasQuoted		= false;

		// Register faked "destructor" in PHP4 to close all connections we might have made
		if (version_compare(PHP_VERSION, '5') == -1) {
			register_shutdown_function(array(&$this, '__destruct'));
		}
	}

	/**
	 * Returns a reference to the global Database object, only creating it
	 * if it doesn't already exist.
	 *
	 * The 'driver' entry in the parameters array specifies the database driver
	 * to be used (defaults to 'mysql' if omitted). All other parameters are
	 * database driver dependent.
	 *
	 * @param array Parameters to be passed to the database driver
	 * @return JDatabase A database object
	 * @since 1.5
	*/
	function &getInstance( $options	= array() )
	{
		static $instances;

		if (!isset( $instances )) {
			$instances = array();
		}

		$signature = serialize( $options );

		if (empty($instances[$signature]))
		{
			$driver		= array_key_exists('driver', $options) 		? $options['driver']	: 'mysql';
			$select		= array_key_exists('select', $options)		? $options['select']	: true;
			$database	= array_key_exists('database', $options)	? $options['database']	: null;

			$driver = preg_replace('/[^A-Z0-9_\.-]/i', '', $driver);
			$path	= dirname(__FILE__).DS.'database'.DS.$driver.'.php';

			if (file_exists($path)) {
				require_once($path);
			} else {
				JError::setErrorHandling(E_ERROR, 'die'); //force error type to die
				$error = JError::raiseError( 500, JTEXT::_('Unable to load Database Driver:') .$driver);
				return $error;
			}

			$adapter	= 'JDatabase'.$driver;
			$instance	= new $adapter($options);

			if ( $error = $instance->getErrorMsg() )
			{
				JError::setErrorHandling(E_ERROR, 'ignore'); //force error type to die
				$error = JError::raiseError( 500, JTEXT::_('Unable to connect to the database:') .$error);
				return $error;
			}


			$instances[$signature] = & $instance;
		}

		return $instances[$signature];
	}

	/**
	 * Database object destructor
	 *
	 * @abstract
	 * @access private
	 * @return boolean
	 * @since 1.5
	 */
	function __destruct()
	{
		return true;
	}

	/**
	 * Get the database connectors
	 *
	 * @access public
	 * @return array An array of available session handlers
	 */
	function getConnectors()
	{
		jimport('joomla.filesystem.folder');
		$handlers = JFolder::files(dirname(__FILE__).DS.'database', '.php$');

		$names = array();
		foreach($handlers as $handler)
		{
			$name = substr($handler, 0, strrpos($handler, '.'));
			$class = 'JDatabase'.ucfirst($name);

			if(!class_exists($class)) {
				require_once(dirname(__FILE__).DS.'database'.DS.$name.'.php');
			}

			if(call_user_func_array( array( trim($class), 'test' ), null)) {
				$names[] = $name;
			}
		}

		return $names;
	}

	/**
	 * Test to see if the MySQLi connector is available
	 *
	 * @static
	 * @access public
	 * @return boolean  True on success, false otherwise.
	 */
	function test()
	{
		return false;
	}

	/**
	 * Determines if the connection to the server is active.
	 *
	 * @access      public
	 * @return      boolean
	 * @since       1.5
	 */
	function connected()
	{
		return false;
	}

	/**
	 * Determines UTF support
	 *
	 * @abstract
	 * @access public
	 * @return boolean
	 * @since 1.5
	 */
	function hasUTF() {
		return false;
	}

	/**
	 * Custom settings for UTF support
	 *
	 * @abstract
	 * @access public
	 * @since 1.5
	 */
	function setUTF() {
	}

	/**
	 * Adds a field or array of field names to the list that are to be quoted
	 *
	 * @access public
	 * @param mixed Field name or array of names
	 * @since 1.5
	 */
	function addQuoted( $quoted )
	{
		if (is_string( $quoted )) {
			$this->_quoted[] = $quoted;
		} else {
			$this->_quoted = array_merge( $this->_quoted, (array)$quoted );
		}
		$this->_hasQuoted = true;
	}

	/**
	 * Splits a string of queries into an array of individual queries
	 *
	 * @access public
	 * @param string The queries to split
	 * @return array queries
	 */
	function splitSql( $queries )
	{
		$start = 0;
		$open = false;
		$open_char = '';
		$end = strlen($queries);
		$query_split = array();
		for($i=0;$i<$end;$i++) {
			$current = substr($queries,$i,1);
			if(($current == '"' || $current == '\'')) {
				$n = 2;
				while(substr($queries,$i - $n + 1, 1) == '\\' && $n < $i) {
					$n ++;
				}
				if($n%2==0) {
					if ($open) {
						if($current == $open_char) {
							$open = false;
							$open_char = '';
						}
					} else {
						$open = true;
						$open_char = $current;
					}
				}
			}
			if(($current == ';' && !$open)|| $i == $end - 1) {
				$query_split[] = substr($queries, $start, ($i - $start + 1));
				$start = $i + 1;
			}
		}

		return $query_split;
	}



	/**
	 * Checks if field name needs to be quoted
	 *
	 * @access public
	 * @param string The field name
	 * @return bool
	 */
	function isQuoted( $fieldName )
	{
		if ($this->_hasQuoted) {
			return in_array( $fieldName, $this->_quoted );
		} else {
			return true;
		}
	}

	/**
	 * Sets the debug level on or off
	 *
	 * @access public
	 * @param int 0 = off, 1 = on
	 */
	function debug( $level ) {
		$this->_debug = intval( $level );
	}

	/**
	 * Get the database UTF-8 support
	 *
	 * @access public
	 * @return boolean
	 * @since 1.5
	 */
	function getUTFSupport() {
		return $this->_utf;
	}

	/**
	 * Get the error number
	 *
	 * @access public
	 * @return int The error number for the most recent query
	 */
	function getErrorNum() {
		return $this->_errorNum;
	}


	/**
	 * Get the error message
	 *
	 * @access public
	 * @return string The error message for the most recent query
	 */
	function getErrorMsg($escaped = false)
	{
		if($escaped) {
			return addslashes($this->_errorMsg);
		} else {
			return $this->_errorMsg;
		}
	}

	/**
	 * Get a database escaped string
	 *
	 * @param	string	The string to be escaped
	 * @param	boolean	Optional parameter to provide extra escaping
	 * @return	string
	 * @access	public
	 * @abstract
	 */
	function getEscaped( $text, $extra = false )
	{
		return;
	}

	/**
	 * Get a database error log
	 *
	 * @access public
	 * @return array
	 */
	function getLog( )
	{
		return $this->_log;
	}

	/**
	 * Get the total number of queries made
	 *
	 * @access public
	 * @return array
	 */
	function getTicker( )
	{
		return $this->_ticker;
	}

	/**
	 * Quote an identifier name (field, table, etc)
	 *
	 * @access	public
	 * @param	string	The name
	 * @return	string	The quoted name
	 */
	function nameQuote( $s )
	{
		// Only quote if the name is not using dot-notation
		if (strpos( $s, '.' ) === false)
		{
			$q = $this->_nameQuote;
			if (strlen( $q ) == 1) {
				return $q . $s . $q;
			} else {
				return $q{0} . $s . $q{1};
			}
		}
		else {
			return $s;
		}
	}
	/**
	 * Get the database table prefix
	 *
	 * @access public
	 * @return string The database prefix
	 */
	function getPrefix()
	{
		return $this->_table_prefix;
	}

	/**
	 * Get the database null date
	 *
	 * @access public
	 * @return string Quoted null/zero date string
	 */
	function getNullDate()
	{
		return $this->_nullDate;
	}

	/**
	 * Sets the SQL query string for later execution.
	 *
	 * This function replaces a string identifier <var>$prefix</var> with the
	 * string held is the <var>_table_prefix</var> class variable.
	 *
	 * @access public
	 * @param string The SQL query
	 * @param string The offset to start selection
	 * @param string The number of results to return
	 * @param string The common table prefix
	 */
	function setQuery( $sql, $offset = 0, $limit = 0, $prefix='#__' )
	{
		$this->_sql		= $this->replacePrefix( $sql, $prefix );
		$this->_limit	= (int) $limit;