owncloud / core

				$offset = 0;

				do {

					$users = $backend->getUsers($search, $limit, $offset);

					foreach ($users as $uid) {

						if (!$backend->userExists($uid)) {

							continue;

						}

						$user = $this->getUserObject($uid, $backend, false);

						$return = $callback($user);

						if ($return === false) {

							break;

						}

					}

					$offset += $limit;

				} while (count($users) >= $limit);

			}

		do {

			$userIds = $this->getSeenUserIds($limit, $offset);

			$offset += $limit;

			foreach ($userIds as $userId) {

				foreach ($this->backends as $backend) {

					if ($backend->userExists($userId)) {

						$user = $this->getUserObject($userId, $backend, false);

						$return = $callback($user);

						if ($return === false) {

							return;

						}

					}

				}

			}

		} while (count($userIds) >= $limit);

	}