/**
  * Object constructor.
  *
  * @param string $type   Engine type ('db' or 'memcache' or 'apc')
  * @param int    $userid User identifier
  * @param string $prefix Key name prefix
  * @param string $ttl    Expiration time of memcache/apc items
  * @param bool   $packed Enables/disabled data serialization.
  *                       It's possible to disable data serialization if you're sure
  *                       stored data will be always a safe string
  */
 function __construct($type, $userid, $prefix = '', $ttl = 0, $packed = true)
 {
     $rcube = rcube::get_instance();
     $type = strtolower($type);
     if ($type == 'memcache') {
         $this->type = 'memcache';
         $this->db = $rcube->get_memcache();
     } else {
         if ($type == 'apc') {
             $this->type = 'apc';
             $this->db = function_exists('apc_exists');
             // APC 3.1.4 required
         } else {
             $this->type = 'db';
             $this->db = $rcube->get_dbh();
             $this->table = $this->db->table_name('cache');
         }
     }
     // convert ttl string to seconds
     $ttl = get_offset_sec($ttl);
     if ($ttl > 2592000) {
         $ttl = 2592000;
     }
     $this->userid = (int) $userid;
     $this->ttl = $ttl;
     $this->packed = $packed;
     $this->prefix = $prefix;
 }

 /**
  * rcube_shared.inc: get_offset_sec()
  */
 function test_get_offset_sec()
 {
     $data = array('1s' => 1, '1m' => 1 * 60, '1h' => 1 * 60 * 60, '1d' => 1 * 60 * 60 * 24, '1w' => 1 * 60 * 60 * 24 * 7, '1y' => (int) '1y', 100 => 100, '100' => 100);
     foreach ($data as $value => $expected) {
         $result = get_offset_sec($value);
         $this->assertEquals($expected, $result, "Invalid get_offset_sec() result for {$value}");
     }
 }

/**
 * Create a unix timestamp with a specified offset from now.
 *
 * @param string $offset_str  String representation of the offset (e.g. 20min, 5h, 2days)
 * @param int    $factor      Factor to multiply with the offset
 *
 * @return int Unix timestamp
 */
function get_offset_time($offset_str, $factor = 1)
{
    return time() + get_offset_sec($offset_str) * $factor;
}

 /**
  * Object constructor.
  *
  * @param rcube_db   $db           DB handler
  * @param rcube_imap $imap         IMAP handler
  * @param int        $userid       User identifier
  * @param bool       $skip_deleted skip_deleted flag
  * @param string     $ttl          Expiration time of memcache/apc items
  * @param int        $threshold    Maximum cached message size
  */
 function __construct($db, $imap, $userid, $skip_deleted, $ttl = 0, $threshold = 0)
 {
     // convert ttl string to seconds
     $ttl = get_offset_sec($ttl);
     if ($ttl > 2592000) {
         $ttl = 2592000;
     }
     $this->db = $db;
     $this->imap = $imap;
     $this->userid = $userid;
     $this->skip_deleted = $skip_deleted;
     $this->ttl = $ttl;
     $this->threshold = $threshold;
     // cache all possible information by default
     $this->mode = self::MODE_INDEX | self::MODE_MESSAGE;
     // database tables
     $this->index_table = $db->table_name('cache_index', true);
     $this->thread_table = $db->table_name('cache_thread', true);
     $this->messages_table = $db->table_name('cache_messages', true);
 }

 /**
  * Garbage collector function for temp files.
  * Remove temp files older than two days
  */
 public function gc_temp()
 {
     $tmp = unslashify($this->config->get('temp_dir'));
     // expire in 48 hours by default
     $temp_dir_ttl = $this->config->get('temp_dir_ttl', '48h');
     $temp_dir_ttl = get_offset_sec($temp_dir_ttl);
     if ($temp_dir_ttl < 6 * 3600) {
         $temp_dir_ttl = 6 * 3600;
     }
     // 6 hours sensible lower bound.
     $expire = time() - $temp_dir_ttl;
     if ($tmp && ($dir = opendir($tmp))) {
         while (($fname = readdir($dir)) !== false) {
             if ($fname[0] == '.') {
                 continue;
             }
             if (@filemtime($tmp . '/' . $fname) < $expire) {
                 @unlink($tmp . '/' . $fname);
             }
         }
         closedir($dir);
     }
 }

 /**
  * Object constructor.
  *
  * @param rcube_db   $db           DB handler
  * @param rcube_imap $imap         IMAP handler
  * @param int        $userid       User identifier
  * @param bool       $skip_deleted skip_deleted flag
  * @param string     $ttl          Expiration time of memcache/apc items
  * @param int        $threshold    Maximum cached message size
  */
 function __construct($db, $imap, $userid, $skip_deleted, $ttl = 0, $threshold = 0)
 {
     // convert ttl string to seconds
     $ttl = get_offset_sec($ttl);
     if ($ttl > 2592000) {
         $ttl = 2592000;
     }
     $this->db = $db;
     $this->imap = $imap;
     $this->userid = $userid;
     $this->skip_deleted = $skip_deleted;
     $this->ttl = $ttl;
     $this->threshold = $threshold;
     // cache all possible information by default
     $this->mode = self::MODE_INDEX | self::MODE_MESSAGE;
 }