class TemporaryTableMapping

class TemporaryTableMapping extends DefaultTableMapping {
    
    /**
     * {@inheritdoc}
     */
    protected function generateFieldTableName(FieldStorageDefinitionInterface $storage_definition, $revision) {
        return static::getTempTableName(parent::generateFieldTableName($storage_definition, $revision));
    }
    
    /**
     * Generates a temporary table name.
     *
     * The method accounts for a maximum table name length of 64 characters.
     *
     * @param string $table_name
     *   The initial table name.
     * @param string $prefix
     *   (optional) The prefix to use for the new table name. Defaults to 'tmp_'.
     *
     * @return string
     *   The final table name.
     */
    public static function getTempTableName($table_name, $prefix = 'tmp_') {
        $tmp_table_name = $prefix . $table_name;
        // Limit the string to 48 characters, keeping a 16 characters margin for db
        // prefixes.
        if (strlen($table_name) > 48) {
            $short_table_name = substr($table_name, 0, 34);
            $table_hash = substr(hash('sha256', $table_name), 0, 10);
            $tmp_table_name = $prefix . $short_table_name . $table_hash;
        }
        return $tmp_table_name;
    }

}