Using benchmark_single.php (from administration repo) I can
measure a speed improvement of 5% to 20% loading the /index.php
when logged in. (when using APC and php-fpm).

The return value almost never changes but this function
is called for every request.

throw exception if encryption was disabled but files are still encrypted to prevent the client from syncing unreadable files

strtotime() will return false and the date will be formatted as the 0-timestamp
(e.g. January 1, 1970 00:00) otherwise.

oc_cache needs to disable file proxys for read/write operation. Otherwise the operation will go through the encryption app which will not work.

split of mimetype detection code from OC_Helper, adding the option for apps to register additional mimetype mappings