7 	private $cache;  variable in helper_plugin_epub
10             $this->cache = unserialize(io_readFile($this->script_file,false));
11             if(!$this->cache) $this->cache = array();  
25          if(isset($this->cache[$md5])) return true;
35 		 unset($this->cache[$md5]);
36          if(isset($this->cache['current_books'][$md5])) {
37             unset($this->cache['current_books'][$md5]);
39 		 io_saveFile($this->script_file,serialize($this->cache));	
43         $epub = $this->cache['current_books'][$md5]['epub'];
44         $file =  mediaFN($this->cache['current_books'][$md5]['epub']);
51         return "File not found: " . $this->cache['current_books'][$md5]['epub'] ;
55             $this->cache[md5($id)] = $id;
56             io_saveFile($this->script_file,serialize($this->cache));	
63          return  $this->cache;
70             $this->cache[$md5] = $id;            
72          if(!isset($this->cache['current_books'])) {
73             $this->cache['current_books'] = array();
75          $this->cache['current_books'][$md5] = array('title'=>$title, 'epub'=>$epub);
76          io_saveFile($this->script_file,serialize($this->cache));
99          if(isset($this->cache['current_books'][$md5])) {
100             return $this->cache['current_books'][$md5];