[TYPO3-core] RFC: #11260: Feature: Speed up xml2array by adding a two level cache

[Fabrizio Branca]

This is an SVN patch request.

Type: New feature

Bugtracker references:
http://bugs.typo3.org/view.php?id=11260

Branches:
trunk

Problem:
When profiling backend code (escpecially when there is templavoila 
involved) you'll notice that t3lib_div::xml2array() is one of the most 
"expensive" parts.

Solution:
By introducing a cache this can by dramatically reduced (have a look at 
http://www.fabrizio-branca.de/fileadmin/statistics_xml2array.ods for 
some profiling statistics) in both backend and frontend.

I've implemented a first level cache (as a static variable) and a second 
level cache (using the new dbbackend), to prevent same xml string to be 
rendered more than once.

Have a nice day,...

Fabrizio