Apply PSR-12 code style (#3886)

[GitHub/WoltLab/WCF.git] / wcfsetup / install / files / lib / system / email / EmailGrammar.class.php

<?php

namespace wcf\system\email;

/**
 * Holds RFC 2045 and RFC 5322 grammar tokens and provides helper functions
 * for dealing with these RFCs.
 *
 * @author  Tim Duesterhus
 * @copyright   2001-2019 WoltLab GmbH
 * @license GNU Lesser General Public License <http://opensource.org/licenses/lgpl-license.php>
 * @package WoltLabSuite\Core\System\Email
 * @since   3.0
 */
final class EmailGrammar
{
    /**
     * Returns a regular expression matching the given type in RFC 5322.
     *
     * @param string $type
     * @return  string
     */
    public static function getGrammar($type)
    {
        switch ($type) {
            case 'VCHAR':
                return '[\x21-\x7E]';
            case 'WSP':
                return '[\x20\x09]';
            case 'FWS':
                return "(?:(?:" . self::getGrammar('WSP') . "*\r\n)?" . self::getGrammar('WSP') . "+)";
            case 'CFWS':
                // note: no support for comments
                return self::getGrammar('FWS');
            case 'quoted-pair':
                return "(?:\\\\(?:" . self::getGrammar('WSP') . "|" . self::getGrammar('VCHAR') . "))";
            case 'atext':
                return "[a-zA-Z0-9!#$%&'*+-/=?^_`{|}~]";
            case 'atom':
                return "(?:" . self::getGrammar('CFWS') . "?" . self::getGrammar('atext') . "+" . self::getGrammar('CFWS') . "?)";
            case 'id-left':
            case 'list-label':
            case 'dot-atom-text':
                return "(?:" . self::getGrammar('atext') . "+(?:\\." . self::getGrammar('atext') . '+)*)';
            case 'no-fold-literal':
                return "(?:\\[" . self::getGrammar('dtext') . "*\\])";
            case 'id-right':
                return "(?:" . self::getGrammar('dot-atom-text') . "|" . self::getGrammar('no-fold-literal') . ")";
            case 'dot-atom':
                return "(?:" . self::getGrammar('CFWS') . "?" . self::getGrammar('dot-atom-text') . self::getGrammar('CFWS') . "?)";
            case 'qtext':
                return '[\x21\x23-\x5B\x5D-\x7E]';
            case 'qcontent':
                return "(?:" . self::getGrammar('qtext') . "|" . self::getGrammar('quoted-pair') . ")";
            case 'quoted-string':
                return "(?:" . self::getGrammar('CFWS') . "?\"(?:" . self::getGrammar('FWS') . "?" . self::getGrammar('qcontent') . ")*" . self::getGrammar('FWS') . "?\"" . self::getGrammar('CFWS') . "?)";
            case 'word':
                return "(?:" . self::getGrammar('atom') . "|" . self::getGrammar('quoted-string') . ")";
            case 'display-name':
            case 'phrase':
                return "(?:" . self::getGrammar('word') . "+)";
            case 'local-part':
                return "(?:" . self::getGrammar('dot-atom') . "|" . self::getGrammar('quoted-string') . ")";
            case 'dtext':
                return '[\x21-\x5A\x5E-\x7E]';
            case 'domain-literal':
                return "(?:" . self::getGrammar('CFWS') . "?\\[(?:" . self::getGrammar('FWS') . "?" . self::getGrammar('dtext') . ")*" . self::getGrammar('FWS') . "?\\]" . self::getGrammar('CFWS') . "?)";
            case 'domain':
                return "(?:" . self::getGrammar('dot-atom') . "|" . self::getGrammar('domain-literal') . ")";
            case 'addr-spec':
                return "(?:" . self::getGrammar('local-part') . "@" . self::getGrammar('domain') . ")";
            case 'angle-addr':
                return "(?:" . self::getGrammar('CFWS') . "?<" . self::getGrammar('addr-spec') . ">" . self::getGrammar('CFWS') . "?)";
            case 'name-addr':
                return "(?:" . self::getGrammar('display-name') . "?" . self::getGrammar('angle-addr') . ")";
            case 'mailbox':
                return "(?:" . self::getGrammar('name-addr') . "|" . self::getGrammar('addr-spec') . ")";
            case 'msg-id':
                return "(?:" . self::getGrammar('CFWS') . "?<" . self::getGrammar('id-left') . "@" . self::getGrammar('id-right') . ">" . self::getGrammar('CFWS') . "?)";
        }
    }

    /**
     * Encode text using quoted printable encoding.
     *
     * @param string $header Header to encode
     * @return  string          Encoded header
     */
    public static function encodeQuotedPrintableHeader($header)
    {
        return \mb_encode_mimeheader($header, "UTF-8", "Q", "\r\n");
    }

    /**
     * Return text either unmodified, if it matches the 'atom' grammar,
     * in double quotes or encoded in quoted printable. Depending on which
     * encoding is necessary.
     *
     * @param string $header Header to encode
     * @return  string          Encoded header
     */
    public static function encodeHeader($header)
    {
        if (!\preg_match('(^' . self::getGrammar('atom') . '$)', $header)) {
            if (($encoded = self::encodeQuotedPrintableHeader($header)) === $header) {
                $header = '"' . \addcslashes($header, '\\"') . '"';
            } else {
                $header = $encoded;
            }
        }

        return $header;
    }

    /**
     * Forbid creation of EmailGrammar objects.
     */
    private function __construct()
    {
        // does nothing
    }
}