Schema::getNormalizedIndexes

protected Schema::getNormalizedIndexes(array $spec)

protected function getNormalizedIndexes(array $spec) {
  $indexes = isset($spec['indexes']) ? $spec['indexes'] : [];
  foreach ($indexes as $index_name => $index_fields) {
    foreach ($index_fields as $index_key => $index_field) {
      // Get the name of the field from the index specification.
      $field_name = is_array($index_field) ? $index_field[0] : $index_field;
      // Check whether the field is defined in the table specification.
      if (isset($spec['fields'][$field_name])) {
        // Get the MySQL type from the processed field.
        $mysql_field = $this->processField($spec['fields'][$field_name]);
        if (in_array($mysql_field['mysql_type'], $this->mysqlStringTypes)) {
          // Check whether we need to shorten the index.
          if ((!isset($mysql_field['type']) || $mysql_field['type'] != 'varchar_ascii') && (!isset($mysql_field['length']) || $mysql_field['length'] > 191)) {
            // Limit the index length to 191 characters.
            $this->shortenIndex($indexes[$index_name][$index_key]);
          }
        }
      }
      else {
        throw new SchemaException("MySQL needs the '$field_name' field specification in order to normalize the '$index_name' index");
      }
    }
  }
  return $indexes;
}