wikimedia/mediawiki-extensions-Translate

<?php
declare( strict_types = 1 );

namespace MediaWiki\Extension\Translate\Validation\Validators;

use InvalidArgumentException;
use MediaWiki\Extension\Translate\MessageLoading\Message;
use MediaWiki\Extension\Translate\Validation\MessageValidator;
use MediaWiki\Extension\Translate\Validation\ValidationIssue;
use MediaWiki\Extension\Translate\Validation\ValidationIssues;

/**
 * Ensures that only the specified escape characters are present.
 * @license GPL-2.0-or-later
 * @since 2020.01
 */
class EscapeCharacterValidator implements MessageValidator {
    /** @var string[] */
    protected $allowedCharacters;
    /** @var string */
    protected $regex;

    /** List of valid escape characters recognized. */
    private const VALID_CHARS = [ '\t', '\n', '\\\'', '\"', '\f', '\r', '\a', '\b', '\\\\' ];

    public function __construct( array $params ) {
        $this->allowedCharacters = $params['values'] ?? [];

        if ( $this->allowedCharacters === [] || !is_array( $this->allowedCharacters ) ) {
            throw new InvalidArgumentException(
                'No values provided for EscapeCharacter validator.'
            );
        }

        $this->regex = $this->buildRegex( $this->allowedCharacters );
    }

    public function getIssues( Message $message, string $targetLanguage ): ValidationIssues {
        $issues = new ValidationIssues();
        $translation = $message->translation();
        preg_match_all( "/$this->regex/U", $translation, $transVars );

        // Check for missing variables in the translation
        $params = $transVars[0];
        if ( count( $params ) ) {
            $messageParams = [
                [ 'PARAMS', $params ],
                [ 'COUNT', count( $params ) ],
                [ 'PARAMS', $this->allowedCharacters ],
                [ 'COUNT', count( $this->allowedCharacters ) ]
            ];

            $issue =
                new ValidationIssue(
                    'escape', 'invalid', 'translate-checks-escape', $messageParams
                );
            $issues->add( $issue );
        }

        return $issues;
    }

    private function buildRegex( array $allowedCharacters ): string {
        $regex = '\\\\[^';
        $prefix = '';
        foreach ( $allowedCharacters as $character ) {
            if ( !in_array( $character, self::VALID_CHARS ) ) {
                throw new InvalidArgumentException(
                    "Invalid escape character encountered: $character during configuration." .
                    'Valid escape characters include: ' . implode( ', ', self::VALID_CHARS )
                );
            }

            if ( $character !== '\\' ) {
                $character = stripslashes( $character );
                // negative look ahead, to avoid "\\ " being treated as an accidental escape
                $prefix = '(?<!\\\\)';
            }

            // This is done because in the regex we need slashes for some characters such as
            // \", \', but not for others such as \n, \t etc
            $normalizedChar = addslashes( $character );
            $regex .= $normalizedChar;
        }
        $regex .= ']';

        return $prefix . $regex;
    }
}