Comment::preSave

public Comment::preSave(EntityStorageInterface $storage)

public function preSave(EntityStorageInterface $storage) {
  parent::preSave($storage);

  if (is_null($this->get('status')->value)) {
    $published = \Drupal::currentUser()->hasPermission('skip comment approval') ? CommentInterface::PUBLISHED : CommentInterface::NOT_PUBLISHED;
    $this->setPublished($published);
  }
  if ($this->isNew()) {
    // Add the comment to database. This next section builds the thread field.
    // @see \Drupal\comment\CommentViewBuilder::buildComponents()
    $thread = $this->getThread();
    if (empty($thread)) {
      if ($this->threadLock) {
        // Thread lock was not released after being set previously.
        // This suggests there's a bug in code using this class.
        throw new \LogicException('preSave() is called again without calling postSave() or releaseThreadLock()');
      }
      if (!$this->hasParentComment()) {
        // This is a comment with no parent comment (depth 0): we start
        // by retrieving the maximum thread level.
        $max = $storage->getMaxThread($this);
        // Strip the "/" from the end of the thread.
        $max = rtrim($max, '/');
        // We need to get the value at the correct depth.
        $parts = explode('.', $max);
        $n = Number::alphadecimalToInt($parts[0]);
        $prefix = '';
      }
      else {
        // This is a comment with a parent comment, so increase the part of
        // the thread value at the proper depth.

        // Get the parent comment:
        $parent = $this->getParentComment();
        // Strip the "/" from the end of the parent thread.
        $parent->setThread((string) rtrim((string) $parent->getThread(), '/'));
        $prefix = $parent->getThread() . '.';
        // Get the max value in *this* thread.
        $max = $storage->getMaxThreadPerThread($this);

        if ($max == '') {
          // First child of this parent. As the other two cases do an
          // increment of the thread number before creating the thread
          // string set this to -1 so it requires an increment too.
          $n = -1;
        }
        else {
          // Strip the "/" at the end of the thread.
          $max = rtrim($max, '/');
          // Get the value at the correct depth.
          $parts = explode('.', $max);
          $parent_depth = count(explode('.', $parent->getThread()));
          $n = Number::alphadecimalToInt($parts[$parent_depth]);
        }
      }
      // Finally, build the thread field for this new comment. To avoid
      // race conditions, get a lock on the thread. If another process already
      // has the lock, just move to the next integer.
      do {
        $thread = $prefix . Number::intToAlphadecimal(++$n) . '/';
        $lock_name = "comment:{$this->getCommentedEntityId()}:$thread";
      } while (!\Drupal::lock()->acquire($lock_name));
      $this->threadLock = $lock_name;
    }
    // We test the value with '===' because we need to modify anonymous
    // users as well.
    if ($this->getOwnerId() === \Drupal::currentUser()->id() && \Drupal::currentUser()->isAuthenticated()) {
      $this->setAuthorName(\Drupal::currentUser()->getUsername());
    }
    // Add the values which aren't passed into the function.
    $this->setThread($thread);
    $this->setHostname(\Drupal::request()->getClientIP());
  }
}