includes/search/SearchSqlite.php
<?php
/**
* SQLite search backend, based upon SearchMysql
*
* 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
*
* @file
* @ingroup Search
*/
use MediaWiki\MediaWikiServices;
use Wikimedia\AtEase\AtEase;
use Wikimedia\Rdbms\IDatabase;
/**
* Search engine hook for SQLite
* @ingroup Search
*/
class SearchSqlite extends SearchDatabase {
/**
* Whether fulltext search is supported by current schema
* @return bool
*/
private function fulltextSearchSupported() {
$dbr = $this->dbProvider->getReplicaDatabase();
$sql = (string)$dbr->newSelectQueryBuilder()
->select( 'sql' )
->from( $dbr->addIdentifierQuotes( 'sqlite_master' ) )
->where( [ 'tbl_name' => $dbr->tableName( 'searchindex', 'raw' ) ] )
->caller( __METHOD__ )->fetchField();
return ( stristr( $sql, 'fts' ) !== false );
}
/**
* Parse the user's query and transform it into an SQL fragment which will
* become part of a WHERE clause
*
* @param string $filteredText
* @param bool $fulltext
* @return string
*/
private function parseQuery( $filteredText, $fulltext ) {
$lc = $this->legalSearchChars( self::CHARS_NO_SYNTAX ); // Minus syntax chars (" and *)
$searchon = '';
$this->searchTerms = [];
$m = [];
if ( preg_match_all( '/([-+<>~]?)(([' . $lc . ']+)(\*?)|"[^"]*")/',
$filteredText, $m, PREG_SET_ORDER ) ) {
foreach ( $m as $bits ) {
AtEase::suppressWarnings();
[ /* all */, $modifier, $term, $nonQuoted, $wildcard ] = $bits;
AtEase::restoreWarnings();
if ( $nonQuoted != '' ) {
$term = $nonQuoted;
$quote = '';
} else {
$term = str_replace( '"', '', $term );
$quote = '"';
}
if ( $searchon !== '' ) {
$searchon .= ' ';
}
// Some languages such as Serbian store the input form in the search index,
// so we may need to search for matches in multiple writing system variants.
$converter = MediaWikiServices::getInstance()->getLanguageConverterFactory()
->getLanguageConverter();
$convertedVariants = $converter->autoConvertToAllVariants( $term );
if ( is_array( $convertedVariants ) ) {
$variants = array_unique( array_values( $convertedVariants ) );
} else {
$variants = [ $term ];
}
// The low-level search index does some processing on input to work
// around problems with minimum lengths and encoding in MySQL's
// fulltext engine.
// For Chinese this also inserts spaces between adjacent Han characters.
$strippedVariants = array_map(
[ MediaWikiServices::getInstance()->getContentLanguage(),
'normalizeForSearch' ],
$variants );
// Some languages such as Chinese force all variants to a canonical
// form when stripping to the low-level search index, so to be sure
// let's check our variants list for unique items after stripping.
$strippedVariants = array_unique( $strippedVariants );
$searchon .= $modifier;
if ( count( $strippedVariants ) > 1 ) {
$searchon .= '(';
}
foreach ( $strippedVariants as $stripped ) {
if ( $nonQuoted && strpos( $stripped, ' ' ) !== false ) {
// Hack for Chinese: we need to toss in quotes for
// multiple-character phrases since normalizeForSearch()
// added spaces between them to make word breaks.
$stripped = '"' . trim( $stripped ) . '"';
}
$searchon .= "$quote$stripped$quote$wildcard ";
}
if ( count( $strippedVariants ) > 1 ) {
$searchon .= ')';
}
// Match individual terms or quoted phrase in result highlighting...
// Note that variants will be introduced in a later stage for highlighting!
$regexp = $this->regexTerm( $term, $wildcard );
$this->searchTerms[] = $regexp;
}
} else {
wfDebug( __METHOD__ . ": Can't understand search query '{$filteredText}'" );
}
$dbr = $this->dbProvider->getReplicaDatabase();
$searchon = $dbr->addQuotes( $searchon );
$field = $this->getIndexField( $fulltext );
return " $field MATCH $searchon ";
}
private function regexTerm( $string, $wildcard ) {
$regex = preg_quote( $string, '/' );
if ( MediaWikiServices::getInstance()->getContentLanguage()->hasWordBreaks() ) {
if ( $wildcard ) {
// Don't cut off the final bit!
$regex = "\b$regex";
} else {
$regex = "\b$regex\b";
}
} else {
// For Chinese, words may legitimately abut other words in the text literal.
// Don't add \b boundary checks... note this could cause false positives
// for Latin chars.
}
return $regex;
}
public function legalSearchChars( $type = self::CHARS_ALL ) {
$searchChars = parent::legalSearchChars( $type );
if ( $type === self::CHARS_ALL ) {
// " for phrase, * for wildcard
$searchChars = "\"*" . $searchChars;
}
return $searchChars;
}
/**
* Perform a full text search query and return a result set.
*
* @param string $term Raw search term
* @return SqlSearchResultSet|null
*/
protected function doSearchTextInDB( $term ) {
return $this->searchInternal( $term, true );
}
/**
* Perform a title-only search query and return a result set.
*
* @param string $term Raw search term
* @return SqlSearchResultSet|null
*/
protected function doSearchTitleInDB( $term ) {
return $this->searchInternal( $term, false );
}
protected function searchInternal( $term, $fulltext ) {
if ( !$this->fulltextSearchSupported() ) {
return null;
}
$filteredTerm =
$this->filter( MediaWikiServices::getInstance()->getContentLanguage()->lc( $term ) );
$dbr = $this->dbProvider->getReplicaDatabase();
// The real type is still IDatabase, but IReplicaDatabase is used for safety.
'@phan-var IDatabase $dbr';
// phpcs:ignore MediaWiki.Usage.DbrQueryUsage.DbrQueryFound
$resultSet = $dbr->query( $this->getQuery( $filteredTerm, $fulltext ), __METHOD__ );
$total = null;
// phpcs:ignore MediaWiki.Usage.DbrQueryUsage.DbrQueryFound
$totalResult = $dbr->query( $this->getCountQuery( $filteredTerm, $fulltext ), __METHOD__ );
$row = $totalResult->fetchObject();
if ( $row ) {
$total = intval( $row->c );
}
$totalResult->free();
return new SqlSearchResultSet( $resultSet, $this->searchTerms, $total );
}
/**
* Return a partial WHERE clause to limit the search to the given namespaces
* @return string
*/
private function queryNamespaces() {
if ( $this->namespaces === null ) {
return ''; # search all
}
if ( $this->namespaces === [] ) {
$namespaces = NS_MAIN;
} else {
$dbr = $this->dbProvider->getReplicaDatabase();
$namespaces = $dbr->makeList( $this->namespaces );
}
return 'AND page_namespace IN (' . $namespaces . ')';
}
/**
* Returns a query with limit for number of results set.
* @param string $sql
* @return string
*/
private function limitResult( $sql ) {
return $this->dbProvider->getReplicaDatabase()->limitResult( $sql, $this->limit, $this->offset );
}
/**
* Construct the full SQL query to do the search.
* The guts shoulds be constructed in queryMain()
* @param string $filteredTerm
* @param bool $fulltext
* @return string
*/
private function getQuery( $filteredTerm, $fulltext ) {
return $this->limitResult(
$this->queryMain( $filteredTerm, $fulltext ) . ' ' .
$this->queryNamespaces()
);
}
/**
* Picks which field to index on, depending on what type of query.
* @param bool $fulltext
* @return string
*/
private function getIndexField( $fulltext ) {
return $fulltext ? 'si_text' : 'si_title';
}
/**
* Get the base part of the search query.
*
* @param string $filteredTerm
* @param bool $fulltext
* @return string
*/
private function queryMain( $filteredTerm, $fulltext ) {
$match = $this->parseQuery( $filteredTerm, $fulltext );
$dbr = $this->dbProvider->getReplicaDatabase();
$page = $dbr->tableName( 'page' );
$searchindex = $dbr->tableName( 'searchindex' );
return "SELECT $searchindex.rowid, page_namespace, page_title " .
"FROM $searchindex CROSS JOIN $page " .
"WHERE page_id=$searchindex.rowid AND $match";
}
private function getCountQuery( $filteredTerm, $fulltext ) {
$match = $this->parseQuery( $filteredTerm, $fulltext );
$dbr = $this->dbProvider->getReplicaDatabase();
$page = $dbr->tableName( 'page' );
$searchindex = $dbr->tableName( 'searchindex' );
return "SELECT COUNT(*) AS c " .
"FROM $searchindex CROSS JOIN $page " .
"WHERE page_id=$searchindex.rowid AND $match " .
$this->queryNamespaces();
}
/**
* Create or update the search index record for the given page.
* Title and text should be pre-processed.
*
* @param int $id
* @param string $title
* @param string $text
*/
public function update( $id, $title, $text ) {
if ( !$this->fulltextSearchSupported() ) {
return;
}
// @todo find a method to do it in a single request,
// couldn't do it so far due to typelessness of FTS3 tables.
$dbw = $this->dbProvider->getPrimaryDatabase();
$dbw->newDeleteQueryBuilder()
->deleteFrom( 'searchindex' )
->where( [ 'rowid' => $id ] )
->caller( __METHOD__ )->execute();
$dbw->newInsertQueryBuilder()
->insertInto( 'searchindex' )
->row( [ 'rowid' => $id, 'si_title' => $title, 'si_text' => $text ] )
->caller( __METHOD__ )->execute();
}
/**
* Update a search index record's title only.
* Title should be pre-processed.
*
* @param int $id
* @param string $title
*/
public function updateTitle( $id, $title ) {
if ( !$this->fulltextSearchSupported() ) {
return;
}
$dbw = $this->dbProvider->getPrimaryDatabase();
$dbw->newUpdateQueryBuilder()
->update( 'searchindex' )
->set( [ 'si_title' => $title ] )
->where( [ 'rowid' => $id ] )
->caller( __METHOD__ )->execute();
}
}