[TYPO3-v4] Interface for Install Tool Checks

[Benjamin Mack]

Hey all,

I'm currently working on a small thing, that is: a check to see if a
TYPO3 installation is currently using the right character-set conversion
tools (iconv, mbstring) or still using the homebrew code which is up to
twice as slow. Well, while I was at it, I thought it'd be nice to have
this check in the 1-2-3 installer automatically as well, not just in the
update wizard. So I wanted to put it in a separate class. So I put
everything in "tx_install_check_charactersettools"

Then I thought of a more general approach: An idea I had for quite some
time was to have a proper check class for each of these things, so it's
easy to add more, and a common thing to check in a TYPO3 extension e.g.
if curl is used...

Right now we checks:
 - in the installer (Basic Configuration, 1-2-3)
 - in the reports module
 - in the introduction package
 - in various other places throughout the core.

So, I'd love to have a common interface / abstract class to define these
checks.

There are different kinds of checks:

Example 1)
 - The php-version is below 5.2.0, TYPO3 shouldn't be installed, and
should not be executed at all

Example 2)
 - Memory Limit: If your memory limit is 16MB, you should still be able
to install TYPO3, but it's not a perfect setup. Just a warning is
produced, maybe a check if you can set it to 32MB through ini_set().

Example 3)
 - No option for the csConv_utils method has been set yet. A message
should be produced that you can upgrade to "mbstring" or whatever was
found on the system. In the 1-2-3, this check should automatically
choose the best option and set it in the localconf.php.

 => Same goes for ImageMagick :)

This way, all the specific code for these checks can be put in their own
classes.

Anyway, the reason I write here was to brainstorm ideas how an interface
for these things should look like in order to put all the different
use-cases in this interface.

I'd love to hear some feedback on this, rather sooner than later in
order to finish it on time for 4.5.

Thanks a lot!

All the best,
Benni.