wikimedia/mediawiki-extensions-CirrusSearch

<?php

namespace CirrusSearch\Extra\Query;

use Elastica\Query\AbstractQuery;

/**
 * Source regex filter for trigram accelerated regex matching.
 *
 * @link https://github.com/wikimedia/search-extra/blob/master/docs/source_regex.md
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 * http://www.gnu.org/copyleft/gpl.html
 */

class SourceRegex extends AbstractQuery {
    /**
     * List of language code that may be used by WMF wikis which are not valid java locales.
     * Use of the empty string falls back to the ROOT locale.
     * Note that the locale here is only used for transforming strings to lowercase
     */
    private const MW_LANG_CODE_TO_JAVA_LOCALE = [
        'be-tarask' => 'be',
        'map-bms' => '',
        'roa-tara' => '',
        'sh' => 'hbs',
        'shy-latn' => '',
    ];

    /**
     * @param null|string $regex optional regex to match against field
     * @param null|string $field optional field who's source to check with the regex
     * @param null|string $ngramField optional field that is indexed with ngrams to
     *  accelerate regex matching
     */
    public function __construct( $regex = null, $field = null, $ngramField = null ) {
        if ( $regex ) {
            $this->setRegex( $regex );
        }
        if ( $field ) {
            $this->setField( $field );
        }
        if ( $ngramField ) {
            $this->setNGramField( $ngramField );
        }
    }

    /**
     * @param string $regex regex to match against field
     * @return self
     */
    public function setRegex( $regex ) {
        return $this->setParam( 'regex', $regex );
    }

    /**
     * @param string $field field who's source to check with the regex
     * @return self
     */
    public function setField( $field ) {
        return $this->setParam( 'field', $field );
    }

    /**
     * @param string $ngramField field that is indexed with ngrams to
     *  accelerate regex matching
     * @return self
     */
    public function setNGramField( $ngramField ) {
        return $this->setParam( 'ngram_field', $ngramField );
    }

    /**
     * @param int $gramSize size of the ngrams extracted for accelerating
     *  the regex.  Defaults to 3 if not set.  That gram size must have been
     *  produced by analyzing the ngramField.
     * @return self
     */
    public function setGramSize( $gramSize ) {
        return $this->setParam( 'gram_size', $gramSize );
    }

    /**
     * @param int $maxExpand maximum range before outgoing automaton arcs are
     *  ignored. Roughly corresponds to the maximum number of characters in a
     *  character class ([abcd]) before it is treated as . for purposes of
     *  acceleration. Defaults to 4.
     * @return self
     */
    public function setMaxExpand( $maxExpand ) {
        return $this->setParam( 'max_expand', $maxExpand );
    }

    /**
     * @param int $maxStatesTraced maximum number of automaton states that can
     *  be traced before the algorithm gives up and assumes the regex is too
     *  complex and throws an error back to the user. Defaults to 10000 which
     *  handily covers all regexes I cared to test.
     * @return self
     */
    public function setMaxStatesTraced( $maxStatesTraced ) {
        return $this->setParam( 'max_states_traced', $maxStatesTraced );
    }

    /**
     * @param int $maxInspect maximum number of source field to run the regex
     *  against before giving up and just declaring all remaining fields not
     *  matching by fiat. Defaults to MAX_INT. Set this to 10000 or something
     *  nice and low to prevent regular expressions that cannot be sped up from
     *  taking up too many resources.
     * @return self
     */
    public function setMaxInspect( $maxInspect ) {
        return $this->setParam( 'max_inspect', $maxInspect );
    }

    /**
     * @param int $maxDeterminizedStates maximum number of automaton states
     *  that Lucene's regex compilation can expand to (even temporarily)
     * @return self
     */
    public function setMaxDeterminizedStates( $maxDeterminizedStates ) {
        return $this->setParam( 'max_determinized_states', $maxDeterminizedStates );
    }

    /**
     * @param bool $caseSensitive is the regex case insensitive?  Defaults to
     *  case insensitive if not set.
     * @return self
     */
    public function setCaseSensitive( $caseSensitive ) {
        return $this->setParam( 'case_sensitive', $caseSensitive );
    }

    /**
     * @param string $locale locale used for case conversions.  Its important that
     *  this matches the locale used for lowercasing in the ngram index.
     * @return self
     */
    public function setLocale( $locale ) {
        $locale = self::MW_LANG_CODE_TO_JAVA_LOCALE[$locale] ?? $locale;
        return $this->setParam( 'locale', $locale );
    }

    /**
     * @param int $maxNgrams The maximum number of ngrams to extracted from the
     *  regex. If more could be extracted from the regex tey are ignored.
     * @return self
     */
    public function setMaxNgramsExtracted( $maxNgrams ) {
        return $this->setParam( 'max_ngrams_extracted', $maxNgrams );
    }

    /**
     * @param int $maxNgramClauses The maximum number of boolean clauses
     *  generated from extracted ngrams.
     * @return self
     */
    public function setMaxNgramClauses( $maxNgramClauses ) {
        return $this->setParam( 'max_ngram_clauses', $maxNgramClauses );
    }
}