getCurrentChecksum example

  public function set($cid, $data, $expire = Cache::PERMANENT, array $tags = []) {
    assert(Inspector::assertAllStrings($tags), 'Cache Tags must be strings.');

    $item = (object) [
      'cid' => $cid,
      'data' => $data,
      'created' => round(microtime(TRUE), 3),
      'expire' => $expire,
      'tags' => array_unique($tags),
      'checksum' => $this->checksumProvider->getCurrentChecksum($tags),
    ];
    $this->writeItem($this->normalizeCid($cid), $item);
  }

  /** * {@inheritdoc} */
  public function delete($cid) {
    $this->storage()->delete($this->normalizeCid($cid));
  }

  

/** * {@inheritdoc} */
  public function set($cid, $data, $expire = CacheBackendInterface::CACHE_PERMANENT, array $tags = []) {
    assert(Inspector::assertAllStrings($tags), 'Cache tags must be strings.');
    $tags = array_unique($tags);
    $cache = new \stdClass();
    $cache->cid = $cid;
    $cache->created = round(microtime(TRUE), 3);
    $cache->expire = $expire;
    $cache->tags = implode(' ', $tags);
    $cache->checksum = $this->checksumProvider->getCurrentChecksum($tags);
    // APCu serializes/unserializes any structure itself.     $cache->serialized = 0;
    $cache->data = $data;

    // Expiration is handled by our own prepareItem(), not APCu.     apcu_store($this->getApcuKey($cid), $cache);
  }

  /** * {@inheritdoc} */
  

assert(Inspector::assertAllStrings($item['tags']), 'Cache Tags must be strings.');
      $item['tags'] = array_unique($item['tags']);
      // Sort the cache tags so that they are stored consistently in the DB.       sort($item['tags']);

      $fields = [
        'cid' => $this->normalizeCid($cid),
        'expire' => $item['expire'],
        'created' => round(microtime(TRUE), 3),
        'tags' => implode(' ', $item['tags']),
        'checksum' => $this->checksumProvider->getCurrentChecksum($item['tags']),
      ];

      // Avoid useless writes.       if ($fields['checksum'] === CacheTagsChecksumInterface::INVALID_CHECKSUM_WHILE_IN_TRANSACTION) {
        continue;
      }

      if (!is_string($item['data'])) {
        $fields['data'] = serialize($item['data']);
        $fields['serialized'] = 1;
      }