MemoryCounterBackend.php

<?php

namespace Drupal\Core\Cache;


/**
 * Defines a memory cache implementation that counts set and get calls.
 *
 * This can be used to mock a cache backend where one needs to know how
 * many times a cache entry was set or requested.
 *
 * @todo On the longrun this backend should be replaced by phpunit mock objects.
 */
class MemoryCounterBackend extends MemoryBackend {
    
    /**
     * Stores a list of cache cid calls keyed by function name.
     *
     * @var array
     */
    protected $counter = [];
    
    /**
     * {@inheritdoc}
     */
    public function get($cid, $allow_invalid = FALSE) {
        $this->increaseCounter(__FUNCTION__, $cid);
        return parent::get($cid, $allow_invalid);
    }
    
    /**
     * {@inheritdoc}
     */
    public function set($cid, $data, $expire = Cache::PERMANENT, array $tags = []) {
        $this->increaseCounter(__FUNCTION__, $cid);
        parent::set($cid, $data, $expire, $tags);
    }
    
    /**
     * {@inheritdoc}
     */
    public function delete($cid) {
        $this->increaseCounter(__FUNCTION__, $cid);
        parent::delete($cid);
    }
    
    /**
     * Increase the counter for a function with a certain cid.
     *
     * @param string $function
     *   The called function.
     * @param string $cid
     *   The cache ID of the cache entry to increase the counter.
     */
    protected function increaseCounter($function, $cid) {
        if (!isset($this->counter[$function][$cid])) {
            $this->counter[$function][$cid] = 1;
        }
        else {
            $this->counter[$function][$cid]++;
        }
    }
    
    /**
     * Returns the call counter for the get, set and delete methods.
     *
     * @param string $method
     *   (optional) The name of the method to return the call counter for.
     * @param string $cid
     *   (optional) The name of the cache id to return the call counter for.
     *
     * @return int|array
     *   An integer if both method and cid is given, an array otherwise.
     */
    public function getCounter($method = NULL, $cid = NULL) {
        if ($method && $cid) {
            return $this->counter[$method][$cid] ?? 0;
        }
        elseif ($method) {
            return $this->counter[$method] ?? [];
        }
        else {
            return $this->counter;
        }
    }
    
    /**
     * Resets the call counter.
     */
    public function resetCounter() {
        $this->counter = [];
    }

}