MessageMail::fillHeadersByOptionHeaders

static function fillHeadersByOptionHeaders(array $headers = array())
{
	static $headerList = null;
	if ($headerList === null)
	{
		$headerList = array();
		// add headers from module options
		$optionHeaders = Option::get('sender', 'mail_headers', '');
		$optionHeaders = !empty($optionHeaders) ? unserialize($optionHeaders, ['allowed_classes' => false]) : array();
		foreach ($optionHeaders as $optionHeader)
		{
			$optionHeader = trim($optionHeader);
			if (!$optionHeader)
			{
				continue;
			}

			$optionHeaderParts = explode(':', $optionHeader);
			$optionHeaderName = isset($optionHeaderParts[0]) ? $optionHeaderParts[0] : '';
			$optionHeaderName = trim($optionHeaderName);
			$optionHeaderValue = isset($optionHeaderParts[1]) ? $optionHeaderParts[1] : '';
			$optionHeaderValue = trim($optionHeaderValue);
			if (!$optionHeaderName || !$optionHeaderValue)
			{
				continue;
			}

			$headerList[$optionHeaderName] = $optionHeaderValue;
		}
	}

	foreach ($headerList as $optionHeaderName => $optionHeaderValue)
	{
		$headers[$optionHeaderName] = $optionHeaderValue;
	}

	return $headers;
}