perf: add Factories::get()

[kenjis]

Description
See #6889 (comment)

• add method to get the shared instance fast.

Benchmark

Test 			Time 	Memory
config() 		0.5684 	0 Bytes
factories::get() 	0.1305 	0 Bytes

<?php

namespace App\Controllers;

use CodeIgniter\Config\Factories;
use CodeIgniter\Debug\Iterator;

class Home extends BaseController
{
    public function index(): string
    {
        $iterator = new Iterator();

        $iterator->add('config()', static function () {
            $config = config('App');
        });

        $iterator->add('Factories::get()', static function () {
            $config = Factories::get('config', 'App');
        });

        return $iterator->run(30000);
    }
}

Profiling

Before:

After:

Environment

$ php -v
PHP 8.1.2-1ubuntu2.14 (cli) (built: Aug 18 2023 11:41:11) (NTS)
Copyright (c) The PHP Group
Zend Engine v4.1.2, Copyright (c) Zend Technologies
    with Zend OPcache v8.1.2-1ubuntu2.14, Copyright (c), by Zend Technologies

$ cat /etc/lsb-release 
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=22.04
DISTRIB_CODENAME=jammy
DISTRIB_DESCRIPTION="Ubuntu 22.04.3 LTS"

$ apache2 -v
Server version: Apache/2.4.52 (Ubuntu)
Server built:   2023-10-26T13:44:44

Checklist:

• Securely signed commits
• Component(s) with PHPDoc blocks, only if necessary or adds value
• Unit testing, with >80% coverage
• User guide updated
• Conforms to style guide

[lonnieezell]

Have you compared using the current config() method, with a version of it that uses Factory::get('config') to see the difference?

I find the helper method config() much more readable and pleasant and what I'd prefer to ask users to use if it makes sense. I'm assuming it speeds it up quite a bit since the big boost is the callStatic method in Factory, right? And as it stands, assuming the config file is used say 1000 times in a page load for an app, we're only looking at 0.000143 second increase with the proposed changes. While I think any performance boost is good, if the a modified config() call is close to the same speed I would prefer to stay with that.

[ddevsr]

I am agree with @lonnieezell, we already introduces config() to get variable config using feature Factories release

[kenjis]

Indeed, the performance improvement in the Welcome page benchmark in this PR was very small. The numbers are so varied that it is hard to tell if there is any real improvement.

However, the performance of Factories should have improved as seen in the profiles.

It might be certainly better to use config(), although there is the overhead of a function call.
That way, the config() implementation can be replaced by another container or something.

However, DI containers, service locators, whatever, they cannot make the framework faster. They can only slow it down. So even if we improve that, it seems impossible to keep up with CI3.