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<?php

/**
 * Simple Machines Forum (SMF)
 *
 * @package SMF
 * @author Simple Machines http://www.simplemachines.org
 * @copyright 2019 Simple Machines and individual contributors
 * @license http://www.simplemachines.org/about/smf/license.php BSD
 *
 * @version 2.1 RC1
 */

if (!defined('SMF'))
    die('Hacking attempt...');

/**
 * Our Cache API class
 *
 * @package cacheAPI
 */
class smf_cache extends cache_api
{
    /**
     * @var string The path to the current $cachedir directory.
     */
    private $cachedir = null;

    /**
     * {@inheritDoc}
     */
    public function __construct()
    {
        parent::__construct();

        // Set our default cachedir.
        $this->setCachedir();
    }

    /**
     * {@inheritDoc}
     */
    public function isSupported($test = false)
    {
        $supported = is_writable($this->cachedir);

        if ($test)
            return $supported;
        return parent::isSupported() && $supported;
    }

    /**
     * {@inheritDoc}
     */
    public function getData($key, $ttl = null)
    {
        $key = $this->prefix . strtr($key, ':/', '-_');
        $cachedir = $this->cachedir;

        // SMF Data returns $value and $expired.  $expired has a unix timestamp of when this expires.
        if (file_exists($cachedir . '/data_' . $key . '.php') && filesize($cachedir . '/data_' . $key . '.php') > 10)
        {
            // Work around Zend's opcode caching (PHP 5.5+), they would cache older files for a couple of seconds
            // causing newer files to take effect a while later.
            if (function_exists('opcache_invalidate'))
                opcache_invalidate($cachedir . '/data_' . $key . '.php', true);

            if (function_exists('apc_delete_file'))
                @apc_delete_file($cachedir . '/data_' . $key . '.php');

            // php will cache file_exists et all, we can't 100% depend on its results so proceed with caution
            @include($cachedir . '/data_' . $key . '.php');
            if (!empty($expired) && isset($value))
            {
                @unlink($cachedir . '/data_' . $key . '.php');
                unset($value);
            }
        }

        return !empty($value) ? $value : null;
    }

    /**
     * {@inheritDoc}
     */
    public function putData($key, $value, $ttl = null)
    {
        $key = $this->prefix . strtr($key, ':/', '-_');
        $cachedir = $this->cachedir;

        // Work around Zend's opcode caching (PHP 5.5+), they would cache older files for a couple of seconds
        // causing newer files to take effect a while later.
        if (function_exists('opcache_invalidate'))
            opcache_invalidate($cachedir . '/data_' . $key . '.php', true);

        if (function_exists('apc_delete_file'))
            @apc_delete_file($cachedir . '/data_' . $key . '.php');

        // Otherwise custom cache?
        if ($value === null)
            @unlink($cachedir . '/data_' . $key . '.php');
        else
        {
            $cache_data = '<' . '?' . 'php if (!defined(\'SMF\')) die; if (' . (time() + $ttl) . ' < time()) $expired = true; else{$expired = false; $value = \'' . addcslashes($value, "\0" . '\\\'') . '\';}' . '?' . '>';

            // Write out the cache file, check that the cache write was successful; all the data must be written
            // If it fails due to low diskspace, or other, remove the cache file
            $fileSize = file_put_contents($cachedir . '/data_' . $key . '.php', $cache_data, LOCK_EX);
            if ($fileSize !== strlen($cache_data))
            {
                @unlink($cachedir . '/data_' . $key . '.php');
                return false;
            }
            else
                return true;
        }
    }

    /**
     * {@inheritDoc}
     */
    public function cleanCache($type = '')
    {
        $cachedir = $this->cachedir;

        // No directory = no game.
        if (!is_dir($cachedir))
            return;

        // Remove the files in SMF's own disk cache, if any
        $dh = opendir($cachedir);
        while ($file = readdir($dh))
        {
            if ($file != '.' && $file != '..' && $file != 'index.php' && $file != '.htaccess' && (!$type || substr($file, 0, strlen($type)) == $type))
                @unlink($cachedir . '/' . $file);
        }
        closedir($dh);

        // Make this invalid.
        $this->invalidateCache();

        return true;
    }

    /**
     * {@inheritDoc}
     */
    public function invalidateCache()
    {
        // We don't worry about $cachedir here, since the key is based on the real $cachedir.
        parent::invalidateCache();

        // Since SMF is file based, be sure to clear the statcache.
        clearstatcache();

        return true;
    }

    /**
     * {@inheritDoc}
     */
    public function cacheSettings(array &$config_vars)
    {
        global $context, $txt;

        $config_vars[] = $txt['cache_smf_settings'];
        $config_vars[] = array('cachedir', $txt['cachedir'], 'file', 'text', 36, 'cache_cachedir');

        if (!isset($context['settings_post_javascript']))
            $context['settings_post_javascript'] = '';

        $context['settings_post_javascript'] .= '
            $("#cache_accelerator").change(function (e) {
                var cache_type = e.currentTarget.value;
                $("#cachedir").prop("disabled", cache_type != "smf");
            });';
    }

    /**
     * Sets the $cachedir or uses the SMF default $cachedir..
     *
     * @access public
     * @param string $dir A valid path
     * @return boolean If this was successful or not.
     */
    public function setCachedir($dir = null)
    {
        global $cachedir;

        // If its invalid, use SMF's.
        if (is_null($dir) || !is_writable($dir))
            $this->cachedir = $cachedir;
        else
            $this->cachedir = $dir;
    }

    /**
     * Gets the current $cachedir.
     *
     * @access public
     * @return string the value of $ttl.
     */
    public function getCachedir()
    {
        return $this->cachedir;
    }

    /**
     * {@inheritDoc}
     */
    public function getVersion()
    {
        return SMF_VERSION;
    }
}

?>