Pimcore\Model\Document\Service::copyRecursive PHP Method

    public function copyRecursive($target, $source)
    {
        // avoid recursion
        if (!$this->_copyRecursiveIds) {
            $this->_copyRecursiveIds = [];
        }
        if (in_array($source->getId(), $this->_copyRecursiveIds)) {
            return;
        }
        if (method_exists($source, "getElements")) {
            $source->getElements();
        }
        $source->getProperties();
        $new = clone $source;
        $new->id = null;
        $new->setChilds(null);
        $new->setKey(Element\Service::getSaveCopyName("document", $new->getKey(), $target));
        $new->setParentId($target->getId());
        $new->setUserOwner($this->_user->getId());
        $new->setUserModification($this->_user->getId());
        $new->setDao(null);
        $new->setLocked(false);
        $new->setCreationDate(time());
        if (method_exists($new, "setPrettyUrl")) {
            $new->setPrettyUrl(null);
        }
        $new->save();
        // add to store
        $this->_copyRecursiveIds[] = $new->getId();
        foreach ($source->getChilds() as $child) {
            $this->copyRecursive($new, $child);
        }
        $this->updateChilds($target, $new);
        // triggers actions after the complete document cloning
        \Pimcore::getEventManager()->trigger('document.postCopy', $new, ['base_element' => $source]);
        return $new;
    }