<?php
#BEGIN_LICENSE
#-------------------------------------------------------------------------
# Module: CGExtensions (c) 2008-2014 by Robert Campbell
#         (calguy1000@cmsmadesimple.org)
#  An addon module for CMS Made Simple to provide useful functions
#  and commonly used gui capabilities to other modules.
#
#-------------------------------------------------------------------------
# CMSMS - CMS Made Simple is (c) 2005 by Ted Kulp (wishy@cmsmadesimple.org)
# Visit the CMSMS Homepage at: http://www.cmsmadesimple.org
#
#-------------------------------------------------------------------------
#
# This program 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.
#
# However, as a special exception to the GPL, this software is distributed
# as an addon module to CMS Made Simple.  You may not use this software
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# Made simple that does not indicate clearly and obviously in its admin
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#END_LICENSE

/**
 * A class to aide in caching data in a key value mechanism.
 * By default this class uses the cms_filecache_driver as a driver.  However, any class that extends cms_cache_driver will work.
 *
 * @package CGExtensions
 * @category Utilities
 * @author  calguy1000 <calguy1000@cmsmadesimple.org>
 * @copyright Copyright 2010 by Robert Campbell
 */

/**
 * A class to aide in caching data in a key value mechanism.
 * By default this class uses the cms_filecache_driver as a driver.  However, any class that extends cms_cache_driver will work.
 *
 * @package CGExtensions
 * @see cms_filecache_driver
 */
class cge_smartcache_handler
{
    /**
     * @ignore
     */
    private $_group = '';

    /**
     * @ignore
     */
    private $_expiry = 3600;

    /**
     * @ignore
     */
    private $_driver;

    /**
     * Constructor.
     *
     * @param array $opts Array of options.   Possible options are:
     *    cache_dir - The absolute directory of the cache location (passed to the driver)
     *    driver    - The name of the driver class to use (cms_filecache_driver is the default)
     *    group     - The name of a group (sort of namespace) to subset keys into
     *    lifetime  - The lifetime of the cached values (in seconds)
     *    autoclean - Whether the cache driver should automatically clean up expired values
     *    locking   - Whether the cache driver should employ locking (if possible)
     */
    public function __construct($opts = null)
    {
        $driver_class = 'cms_filecache_driver';
        $driver_opts = array('cache_dir'=>TMP_CACHE_LOCATION,
                             'lifetime'=>3600,
                             'locking'=>1,
                             'autoclean'=>1);

        if( is_array($opts) && count($opts) ) {
            foreach( $opts as $key => $value ) {
                switch( $key ) {
                case 'group':
                    $value = trim($value);
                    if( !is_string($value) ) {
                        throw new Exception('Group '.$value.' is invalid');
                    }
                    $this->_group = $value;
                    break;

                case 'driver':
                    if( !class_exists($value) ) {
                        throw new Exception('Driver '.$value.' not specified');
                    }
                    $driver_class = $value;
                    break;

                case 'cache_dir':
                    if( !is_writable($value) ) {
                        throw new Exception('Directory '.$value.' is not writable');
                    }
                    $driver_opts['cache_dir'] = $value;
                    break;

                case 'lifetime':
                    if( !is_int($value) ) {
                        throw new Exception('Lifetime '.$value.' is invalid');
                    }
                    $value = max(30,min(12*3600,$value));
                    $driver_opts['lifetime'] = $value;
                    break;

                case 'locking':
                    $value = (int)$value;
                    if( $value > 0 ) $value = 1;
                    $driver_opts['locking'] = $value;
                    break;

                case 'autoclean':
                    $value = (int)$value;
                    if( $value > 0 ) $value = 1;
                    $driver_opts['autoclean'] = $value;
                }
            }
        }

        $this->_driver = new $driver_class($driver_opts);
    }

    /**
     * Set the group (namespace) to store variables in.
     *
     * @param string $group
     */
    public function set_group($group)
    {
        if( !is_array($group) && !is_object($group) ) $this->_group = $group;
    }

    /**
     * Clear all cached data.
     *
     * @param string $group An optional group name.  If not specified, the current group is used.
     * @return bool
     */
    final public function clear($group = '')
    {
        if( is_object($this->_driver) ) {
            if( !$group ) $group = $this->_group;
            return $this->_driver->clear($group);
        }
        return FALSE;
    }

    /**
     * Get the specified cached data value
     *
     * @param string $key The key
     * @param string $group An optional group.  If not specified, the current group value is used.
     * @return mixed
     */
    final public function get($key,$group = '')
    {
        if( is_object($this->_driver) ) {
            if( !$group ) $group = $this->_group;
            return $this->_driver->get($key,$group);
        }
    }

    /**
     * Test if the specified data value exists within the cache.
     *
     * @param string $key The key
     * @param string $group An optional group.  If not specified, the current group value is used.
     * @return bool
     */
    final public function exists($key,$group = '')
    {
        if( is_object($this->_driver) ) {
            if( !$group ) $group = $this->_group;
            return $this->_driver->exists($key,$group);
        }
        return FALSE;
    }

    /**
     * Erase the specified data value from the cache.
     *
     * @param string $key The key
     * @param string $group An optional group.  If not specified, the current group value is used.
     */
    final public function erase($key,$group = '')
    {
        if( is_object($this->_driver) ) {
            if( !$group ) $group = $this->_group;
            return $this->_driver->erase($key,$group);
        }
    }

    /**
     * Store data into the cache
     *
     * @param string $key
     * @param mixed  $value
     * @param string $group An optional group.  If not specified, the current group value is used.
     */
    final public function set($key,$value,$group = '')
    {
        if( is_object($this->_driver) ) {
            if( !$group ) $group = $this->_group;
            return $this->_driver->set($key,$value,$group);
        }
    }
} // end of class

?>
