[TYPO3-project-4-3] autoloader using SPL

[Ingo Renner]

Dmitry Dulepov [typo3] wrote:
> Hi!
> 
> Ingo Renner wrote:
>> The problem with TYPO3 and its extensions is that we do not have a 
>> "default" filesytem structure how/where classes are located and how 
>> their files are named.
> 
> We actually have to certain degree...
> 
> <skip>
> 
>> However I think that we can also come up with autoloading for classes 
>> located in extensions that do not follow a certain schema or structure 
>> of placing classes in certain folders. (We should establish that though)
>>
>> The idea I had is to recursivly run through all directories and see 
>> which classes are in which files. Collect this information in a kind 
>> of key => value "registry"/array. This collected information should 
>> then of course be stored somewhere (using the new caching framework 
>> maybe?!).
> 
> t3lib_ and tslib_ do not need this. So it is tx_ and files in typo3/.

Well, they do need this too, there are a few exceptions like 
t3lib_basicFileFunctions is in class.t3lib_basicfilefunc.php instead of 
class.t3lib_basicfilefunctions.php

>> All in all I think that having autoloading in 4.3 is _a must_. When 
>> doing some profiling using xdebug + kcachegrind I found that one 
>> aspect that slows TYPO3 down a lot are the many many includes we do as 
>> each include means a hard disk read access - and we all know that HDDs 
>> are slow.
> 
> Firsts, does require_once is the problem too?

??

> Secondly, you do not need HDD if you have a real server with enough 
> memory, OS cache and eAccelerator with proper shared memory settings. 
> This should be a default configuration. I am not talking of course about 
> shared hosting.

You'll always need or some kind of slow but large memory storage.

> Thirdly, I am not sure that looking up the registry and including the 
> file is faster than just including the file with require_once. 

The problem is that, require_once itself is slow already as it does a 
HDD read access even if the file/class is loaded already - can't 
remember though where I read that.

> On the 
> other hand many TYPO3 files always include files but use them only in 
> some cases. 

That's exactly the problem.

> Here autoload can be a good alternative. But I still doubt 
> we should blindly go and remove all require_once in favor of autoload. 
> Blind actions never do anything good.

This is not a blinf action as I described how I think it 
should/would/would work. In the worst case it's just as slow/fast as the 
  current way of including all files. In all other cases it's most 
likely going to be faster.

> Additionally, the question: will autoloaded classes be cacheable with 
> PHP accelerators? I am asking because there are *rumors* that they are 
> not cached. eAccelerator improves speed by more than 10 times and I do 
> not want to loose that.

I'm not sure, but I guess so, why shouldn't they? It's still an actual 
include/require that happens.


Ingo

-- 
Ingo Renner
TYPO3 Core Developer, Release Manager TYPO3 4.2