original_string: protected function read($file)
      {
          $data = null;
          $key  = $file;
          $file = $this->getFileName($file);
  
          if ( file_exists($file))
          {
              // if cache file not expire
              if (filemtime($file) >= time())
              {
                  echo "read cache<br/>";
                  $data = file_get_contents($file);
                  $data = ($this->base64Encode) ? base64_decode($data) : $data;
                  $data = unserialize($data);
                  static::$keys[$key] = true;
              }
              else
              {
                  unset(static::$keys[$key]);
                  unlink($file);
              }
          }
  
          return $data;
      }
code: protected function read($file)
      {
          $data = null;
          $key  = $file;
          $file = $this->getFileName($file);
  
          if ( file_exists($file))
          {
              // if cache file not expire
              if (filemtime($file) >= time())
              {
                  echo "read cache<br/>";
                  $data = file_get_contents($file);
                  $data = ($this->base64Encode) ? base64_decode($data) : $data;
                  $data = unserialize($data);
                  static::$keys[$key] = true;
              }
              else
              {
                  unset(static::$keys[$key]);
                  unlink($file);
              }
          }
  
          return $data;
      }
code_tokens: protected function read ( $ file ) { $ data = null ; $ key = $ file ; $ file = $ this -> getFileName ( $ file ) ; if ( file_exists ( $ file ) ) { // if cache file not expire
   if ( filemtime ( $ file ) >= time ( ) ) { echo "read cache<br/>" ; $ data = file_get_contents ( $ file ) ; $ data = ( $ this -> base64Encode ) ? base64_decode ( $ data ) : $ data ; $ data = unserialize ( $ data ) ; static :: $ keys [ $ key ] = true ; } else { unset ( static :: $ keys [ $ key ] ) ; unlink ( $ file ) ; } } return $ data ; }
docstring: Read cache file
  
  @param string $file
  @return mixed|null
docstring_tokens: Read cache file