connection_manager.php

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<?php
/* SVN FILE: $Id: connection_manager.php 8114 2009-03-17 21:10:28Z renan.saddam $ */
/**
 * Datasource connection manager
 *
 * Provides an interface for loading and enumerating connections defined in app/config/database.php
 *
 * PHP versions 4 and 5
 *
 * CakePHP(tm) :  Rapid Development Framework (http://www.cakephp.org)
 * Copyright 2005-2008, Cake Software Foundation, Inc. (http://www.cakefoundation.org)
 *
 * Licensed under The MIT License
 * Redistributions of files must retain the above copyright notice.
 *
 * @filesource
 * @copyright     Copyright 2005-2008, Cake Software Foundation, Inc. (http://www.cakefoundation.org)
 * @link          http://www.cakefoundation.org/projects/info/cakephp CakePHP(tm) Project
 * @package       cake
 * @subpackage    cake.cake.libs.model
 * @since         CakePHP(tm) v 0.10.x.1402
 * @version       $Revision: 8114 $
 * @modifiedby    $LastChangedBy: renan.saddam $
 * @lastmodified  $Date: 2009-03-17 17:10:28 -0400 (Tue, 17 Mar 2009) $
 * @license       http://www.opensource.org/licenses/mit-license.php The MIT License
 */
uses ('model' . DS . 'datasources' . DS . 'datasource');
config('database');

/**
 * Manages loaded instances of DataSource objects
 *
 * Long description for file
 *
 * @package       cake
 * @subpackage    cake.cake.libs.model
 */
class ConnectionManager extends Object {
/**
 * Holds a loaded instance of the Connections object
 *
 * @var DATABASE_CONFIG
 * @access public
 */
    var $config = null;
/**
 * Holds instances DataSource objects
 *
 * @var array
 * @access protected
 */
    var $_dataSources = array();
/**
 * Contains a list of all file and class names used in Connection settings
 *
 * @var array
 * @access protected
 */
    var $_connectionsEnum = array();
/**
 * Constructor.
 *
 */
    function __construct() {
        if (class_exists('DATABASE_CONFIG')) {
            $this->config =& new DATABASE_CONFIG();
        }
    }
/**
 * Gets a reference to the ConnectionManger object instance
 *
 * @return object Instance
 * @access public
 * @static
 */
    function &getInstance() {
        static $instance = array();

        if (!$instance) {
            $instance[0] =& new ConnectionManager();
        }

        return $instance[0];
    }
/**
 * Gets a reference to a DataSource object
 *
 * @param string $name The name of the DataSource, as defined in app/config/database.php
 * @return object Instance
 * @access public
 * @static
 */
    function &getDataSource($name) {
        $_this =& ConnectionManager::getInstance();

        if (!empty($_this->_dataSources[$name])) {
            $return =& $_this->_dataSources[$name];
            return $return;
        }

        $connections = $_this->enumConnectionObjects();
        if (!empty($connections[$name])) {
            $conn = $connections[$name];
            $class = $conn['classname'];
            $_this->loadDataSource($name);
            $_this->_dataSources[$name] =& new $class($_this->config->{$name});
            $_this->_dataSources[$name]->configKeyName = $name;
        } else {
            trigger_error(sprintf(__("ConnectionManager::getDataSource - Non-existent data source %s", true), $name), E_USER_ERROR);
            return null;
        }

        $return =& $_this->_dataSources[$name];
        return $return;
    }
/**
 * Gets the list of available DataSource connections
 *
 * @return array List of available connections
 * @access public
 * @static
 */
    function sourceList() {
        $_this =& ConnectionManager::getInstance();
        return array_keys($_this->_dataSources);
    }
/**
 * Gets a DataSource name from an object reference
 *
 * @param object $source DataSource object
 * @return string Datasource name
 * @access public
 * @static
 */
    function getSourceName(&$source) {
        $_this =& ConnectionManager::getInstance();
        $names = array_keys($_this->_dataSources);
        for ($i = 0; $i < count($names); $i++) {
            if ($_this->_dataSources[$names[$i]] === $source) {
                return $names[$i];
            }
        }
        return null;
    }
/**
 * Loads the DataSource class for the given connection name
 *
 * @param mixed $connName A string name of the connection, as defined in app/config/database.php,
 *                        or an array containing the filename (without extension) and class name of the object,
 *                        to be found in app/models/datasources/ or cake/libs/model/datasources/.
 * @return boolean True on success, null on failure or false if the class is already loaded
 * @access public
 * @static
 */
    function loadDataSource($connName) {
        $_this =& ConnectionManager::getInstance();

        if (is_array($connName)) {
            $conn = $connName;
        } else {
            $connections = $_this->enumConnectionObjects();
            $conn = $connections[$connName];
        }

        if (!empty($conn['parent'])) {
            $_this->loadDataSource($conn['parent']);
        }

        if (class_exists($conn['classname'])) {
            return false;
        }

        if (file_exists(MODELS . 'datasources' . DS . $conn['filename'] . '.php')) {
            require (MODELS . 'datasources' . DS . $conn['filename'] . '.php');
        } elseif (fileExistsInPath(LIBS . 'model' . DS . 'datasources' . DS . $conn['filename'] . '.php')) {
            require (LIBS . 'model' . DS . 'datasources' . DS . $conn['filename'] . '.php');
        } else {
            $error = __('Unable to load DataSource file %s.php', true);
            trigger_error(sprintf($error, $conn['filename']), E_USER_ERROR);
            return null;
        }
    }
/**
 * Gets a list of class and file names associated with the user-defined DataSource connections
 *
 * @return array An associative array of elements where the key is the connection name
 *               (as defined in Connections), and the value is an array with keys 'filename' and 'classname'.
 * @access public
 * @static
 */
    function enumConnectionObjects() {
        $_this =& ConnectionManager::getInstance();

        if (!empty($_this->_connectionsEnum)) {
            return $_this->_connectionsEnum;
        }
        $connections = get_object_vars($_this->config);

        if ($connections != null) {
            foreach ($connections as $name => $config) {
                $_this->_connectionsEnum[$name] = $_this->__getDriver($config);
            }
            return $_this->_connectionsEnum;
        } else {
            $_this->cakeError('missingConnection', array(array('className' => 'ConnectionManager')));
        }
    }
/**
 * Dynamically creates a DataSource object at runtime, with the given name and settings
 *
 * @param string $name The DataSource name
 * @param array $config The DataSource configuration settings
 * @return object A reference to the DataSource object, or null if creation failed
 * @access public
 * @static
 */
    function &create($name = '', $config = array()) {
        $_this =& ConnectionManager::getInstance();

        if (empty($name) || empty($config) || array_key_exists($name, $_this->_connectionsEnum)) {
            $null = null;
            return $null;
        }

        $_this->config->{$name} = $config;
        $_this->_connectionsEnum[$name] = $_this->__getDriver($config);
        $return =& $_this->getDataSource($name);
        return $return;
    }
/**
 * Returns the file, class name, and parent for the given driver.
 *
 * @return array An indexed array with: filename, classname, and parent
 * @access private
 */
    function __getDriver($config) {
        if (!isset($config['datasource'])) {
            $config['datasource'] = 'dbo';
        }

        if (isset($config['driver']) && $config['driver'] != null && !empty($config['driver'])) {
            $filename = $config['datasource'] . DS . $config['datasource'] . '_' . $config['driver'];
            $classname = Inflector::camelize(strtolower($config['datasource'] . '_' . $config['driver']));
            $parent = $this->__getDriver(array('datasource' => $config['datasource']));
        } else {
            $filename = $config['datasource'] . '_source';
            $classname = Inflector::camelize(strtolower($config['datasource'] . '_source'));
            $parent = null;
        }
        return array('filename'  => $filename, 'classname' => $classname, 'parent' => $parent);
    }
/**
 * Destructor.
 *
 * @access private
 */
    function __destruct() {
        if (Configure::read('Session.save') == 'database' && function_exists('session_write_close')) {
            session_write_close();
        }
    }
}
?>

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