MessageEventManager::getMailsFieldsData

private function getMailsFieldsData($eventData, $requiredKeys, $filter)
{
	$fieldsData = $eventData;
	$missingKeys = $requiredKeys;
	$messagesCount = count($eventData);
	if ($messagesCount)
	{
		foreach ($requiredKeys as $requiredKey)
		{
			if (count(array_column($eventData, $requiredKey)) === $messagesCount)
			{
				$missingKeys = array_diff($missingKeys, [$requiredKey]);
			}
		}
	}

	if (!empty($missingKeys) && !empty($filter))
	{
		$fieldsData = $this->getMailMessagesList($filter, $missingKeys);
	}
	$results = [];
	foreach ($fieldsData as $index => $mailFieldsData)
	{
		$results[$mailFieldsData['HEADER_MD5']] = $mailFieldsData;
	}
	return $results;
}