CacheTagsInvalidator.php

<?php

namespace Drupal\Core\Cache;

use Drupal\Component\Assertion\Inspector;

/**
 * Passes cache tag events to classes that wish to respond to them.
 */
class CacheTagsInvalidator implements CacheTagsInvalidatorInterface {
    
    /**
     * Holds an array of cache tags invalidators.
     *
     * @var \Drupal\Core\Cache\CacheTagsInvalidatorInterface[]
     */
    protected $invalidators = [];
    
    /**
     * Holds an array of cache bins that support invalidations.
     *
     * @var \Drupal\Core\Cache\CacheTagsInvalidatorInterface[]
     */
    protected array $bins = [];
    
    /**
     * {@inheritdoc}
     */
    public function invalidateTags(array $tags) {
        assert(Inspector::assertAllStrings($tags), 'Cache tags must be strings.');
        // Notify all added cache tags invalidators.
        foreach ($this->invalidators as $invalidator) {
            $invalidator->invalidateTags($tags);
        }
        // Additionally, notify each cache bin if it implements the service.
        foreach ($this->bins as $bin) {
            $bin->invalidateTags($tags);
        }
    }
    
    /**
     * Reset statically cached tags in all cache tag checksum services.
     *
     * This is only used by tests.
     */
    public function resetChecksums() {
        foreach ($this->invalidators as $invalidator) {
            if ($invalidator instanceof CacheTagsChecksumInterface) {
                $invalidator->reset();
            }
        }
    }
    
    /**
     * Adds a cache tags invalidator.
     *
     * @param \Drupal\Core\Cache\CacheTagsInvalidatorInterface $invalidator
     *   A cache invalidator.
     */
    public function addInvalidator(CacheTagsInvalidatorInterface $invalidator) {
        $this->invalidators[] = $invalidator;
    }
    
    /**
     * Adds a cache bin.
     *
     * @param \Drupal\Core\Cache\CacheBackendInterface $bin
     *   A cache bin.
     */
    public function addBin(CacheBackendInterface $bin) : void {
        if ($bin instanceof CacheTagsInvalidatorInterface) {
            $this->bins[] = $bin;
        }
    }

}