PSR-4 (Autoloader) Support

[joshua-bn]

Summary (*)

Add support for PSR-4 autoloading in addition to the current PSR-0 support.

Examples (*)

\OpenMage\SomeModule\Model\SomeClass => app/code/OpenMage/SomeModule/Model/SomeClass.php

I want to be able to do $someClass = new SomeClass and it load the correct file (assuming this is in the \OpenMage\SomeModule\Model\ namespace or I have a use statement at the top of the file)

Proposed solution

Add another autoloader. https://www.php-fig.org/psr/psr-4/examples/

[joshua-bn]

<?php

class Varien_Autoload
{
    protected static ?Varien_Autoload $_instance = null;

    public static function instance(): Varien_Autoload
    {
        if (!self::$_instance) {
            self::$_instance = new Varien_Autoload();
        }
        return self::$_instance;
    }

    public static function register(): void
    {
        spl_autoload_register([self::instance(), 'autoload']);
    }

    public function autoload(string $class): bool
    {
        foreach ($this->getPaths($class) as $path) {
            if (@include $path) {
                return true;
            }
        }

        return false;
    }

    private function getPaths(string $class): array
    {
        return [
            $this->getPsr0Path($class),
            $this->getPsr4Path($class),
        ];
    }

    private function classPartsToUpperCase(string $class, string $separator): string
    {
        return str_replace(' ', DIRECTORY_SEPARATOR, ucwords(str_replace($separator, ' ', $class)));
    }

    private function getPsr0Path(string $class)
    {
        return $this->classPartsToUpperCase($class, '_') . '.php';
    }

    private function getPsr4Path(string $class)
    {
        return $this->classPartsToUpperCase($class, '\\') . '.php';
    }
}

EDIT: I forgot that file_exists() won't use include_path. Considering it's an anti-pattern anyway, it makes sense. So, I just made it try to include the file. I quickly tested this and it works.

[joshua-bn]

This will not work with the service locator methods. That's a different story and one that requires a lot more work and testing. This is just to allow you to do simple things like use OpenMage\Model\SomeClass; new SomeClass instead of OpenMage_Model_SomeClass. It is the prerequisite for the service locator method stories.