class LazyLoadingMetadataFactory

class LazyLoadingMetadataFactory implements MetadataFactoryInterface {
    
    /**
     * The loaded metadata, indexed by class name.
     *
     * @var ClassMetadata[]
     */
    protected array $loadedClasses = [];
    public function __construct(?LoaderInterface $loader = null, ?CacheItemPoolInterface $cache = null) {
    }
    
    /**
     * If the method was called with the same class name (or an object of that
     * class) before, the same metadata instance is returned.
     *
     * If the factory was configured with a cache, this method will first look
     * for an existing metadata instance in the cache. If an existing instance
     * is found, it will be returned without further ado.
     *
     * Otherwise, a new metadata instance is created. If the factory was
     * configured with a loader, the metadata is passed to the
     * {@link LoaderInterface::loadClassMetadata()} method for further
     * configuration. At last, the new object is returned.
     */
    public function getMetadataFor(mixed $value) : MetadataInterface {
        if (!\is_object($value) && !\is_string($value)) {
            throw new NoSuchMetadataException(\sprintf('Cannot create metadata for non-objects. Got: "%s".', get_debug_type($value)));
        }
        $class = ltrim(\is_object($value) ? $value::class : $value, '\\');
        if (isset($this->loadedClasses[$class])) {
            return $this->loadedClasses[$class];
        }
        if (!class_exists($class) && !interface_exists($class, false)) {
            throw new NoSuchMetadataException(\sprintf('The class or interface "%s" does not exist.', $class));
        }
        $cacheItem = $this->cache?->getItem($this->escapeClassName($class));
        if ($cacheItem?->isHit()) {
            $metadata = $cacheItem->get();
            // Include constraints from the parent class
            $this->mergeConstraints($metadata);
            return $this->loadedClasses[$class] = $metadata;
        }
        $metadata = new ClassMetadata($class);
        $this->loader?->loadClassMetadata($metadata);
        if (null !== $cacheItem) {
            $this->cache
                ->save($cacheItem->set($metadata));
        }
        // Include constraints from the parent class
        $this->mergeConstraints($metadata);
        return $this->loadedClasses[$class] = $metadata;
    }
    private function mergeConstraints(ClassMetadata $metadata) : void {
        if ($metadata->getReflectionClass()
            ->isInterface()) {
            return;
        }
        // Include constraints from the parent class
        if ($parent = $metadata->getReflectionClass()
            ->getParentClass()) {
            $metadata->mergeConstraints($this->getMetadataFor($parent->name));
        }
        // Include constraints from all directly implemented interfaces
        foreach ($metadata->getReflectionClass()
            ->getInterfaces() as $interface) {
            if ('Symfony\\Component\\Validator\\GroupSequenceProviderInterface' === $interface->name) {
                continue;
            }
            if ($parent && \in_array($interface->getName(), $parent->getInterfaceNames(), true)) {
                continue;
            }
            $metadata->mergeConstraints($this->getMetadataFor($interface->name));
        }
    }
    public function hasMetadataFor(mixed $value) : bool {
        if (!\is_object($value) && !\is_string($value)) {
            return false;
        }
        $class = ltrim(\is_object($value) ? $value::class : $value, '\\');
        return class_exists($class) || interface_exists($class, false);
    }
    
    /**
     * Replaces backslashes by dots in a class name.
     */
    private function escapeClassName(string $class) : string {
        if (str_contains($class, '@')) {
            // anonymous class: replace all PSR6-reserved characters
            return str_replace([
                "\x00",
                '\\',
                '/',
                '@',
                ':',
                '{',
                '}',
                '(',
                ')',
            ], '.', $class);
        }
        return str_replace('\\', '.', $class);
    }

}