class ProviderFilterDecorator

class ProviderFilterDecorator implements DiscoveryInterface {
    use DiscoveryTrait;
    
    /**
     * The Discovery object being decorated.
     *
     * @var \Drupal\Component\Plugin\Discovery\DiscoveryInterface
     */
    protected $decorated;
    
    /**
     * A callable for testing if a provider exists.
     *
     * @var callable
     */
    protected $providerExists;
    
    /**
     * Constructs a InheritProviderDecorator object.
     *
     * @param \Drupal\Component\Plugin\Discovery\DiscoveryInterface $decorated
     *   The object implementing DiscoveryInterface that is being decorated.
     * @param callable $provider_exists
     *   A callable, gets passed a provider name, should return TRUE if the
     *   provider exists and FALSE if not.
     */
    public function __construct(DiscoveryInterface $decorated, callable $provider_exists) {
        $this->decorated = $decorated;
        $this->providerExists = $provider_exists;
    }
    
    /**
     * Removes plugin definitions with non-existing providers.
     *
     * @param mixed[] $definitions
     *   An array of plugin definitions (empty array if no definitions were
     *   found). Keys are plugin IDs.
     * @param callable $provider_exists
     *   A callable, gets passed a provider name, should return TRUE if the
     *   provider exists and FALSE if not.
     *
     * @return array|\mixed[]
     *   An array of plugin definitions. If a definition is an array and has a
     *   provider key that provider is guaranteed to exist.
     */
    public static function filterDefinitions(array $definitions, callable $provider_exists) {
        // Besides what the caller accepts, we also accept core or component.
        $provider_exists = function ($provider) use ($provider_exists) {
            return in_array($provider, [
                'core',
                'component',
            ]) || $provider_exists($provider);
        };
        return array_filter($definitions, function ($definition) use ($provider_exists) {
            // Plugin definitions can be objects (for example, Typed Data) those will
            // become empty array here and cause no problems.
            $definition = (array) $definition + [
                'provider' => [],
            ];
            // There can be one or many providers, handle them as multiple always.
            $providers = (array) $definition['provider'];
            return count($providers) == count(array_filter($providers, $provider_exists));
        });
    }
    
    /**
     * {@inheritdoc}
     */
    public function getDefinitions() {
        return static::filterDefinitions($this->decorated
            ->getDefinitions(), $this->providerExists);
    }
    
    /**
     * Passes through all unknown calls onto the decorated object.
     *
     * @param string $method
     *   The method to call on the decorated object.
     * @param array $args
     *   Call arguments.
     *
     * @return mixed
     *   The return value from the method on the decorated object.
     */
    public function __call($method, array $args) {
        return call_user_func_array([
            $this->decorated,
            $method,
        ], $args);
    }

}