Nette\Caching\Storages\SQLiteJournal::clean PHP Method

    public function clean(array $conditions)
    {
        if (!$this->pdo) {
            $this->open();
        }
        if (!empty($conditions[Cache::ALL])) {
            $this->pdo->exec('
				BEGIN;
				DELETE FROM tags;
				DELETE FROM priorities;
				COMMIT;
			');
            return NULL;
        }
        $unions = $args = [];
        if (!empty($conditions[Cache::TAGS])) {
            $tags = (array) $conditions[Cache::TAGS];
            $unions[] = 'SELECT DISTINCT key FROM tags WHERE tag IN (?' . str_repeat(', ?', count($tags) - 1) . ')';
            $args = $tags;
        }
        if (!empty($conditions[Cache::PRIORITY])) {
            $unions[] = 'SELECT DISTINCT key FROM priorities WHERE priority <= ?';
            $args[] = (int) $conditions[Cache::PRIORITY];
        }
        if (empty($unions)) {
            return [];
        }
        $unionSql = implode(' UNION ', $unions);
        $this->pdo->exec('BEGIN IMMEDIATE');
        $stmt = $this->pdo->prepare($unionSql);
        $stmt->execute($args);
        $keys = $stmt->fetchAll(\PDO::FETCH_COLUMN, 0);
        if (empty($keys)) {
            $this->pdo->exec('COMMIT');
            return [];
        }
        $this->pdo->prepare("DELETE FROM tags WHERE key IN ({$unionSql})")->execute($args);
        $this->pdo->prepare("DELETE FROM priorities WHERE key IN ({$unionSql})")->execute($args);
        $this->pdo->exec('COMMIT');
        return $keys;
    }