wikimedia/mediawiki-core

<?php
/**
 * 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
 */
namespace Wikimedia\Rdbms\Platform;

use Wikimedia\Rdbms\Query;

/**
 * @since 1.38
 * @see ISQLPlatform
 */
class SqlitePlatform extends SQLPlatform {
    public function buildGreatest( $fields, $values ) {
        return $this->buildSuperlative( 'MAX', $fields, $values );
    }

    public function buildLeast( $fields, $values ) {
        return $this->buildSuperlative( 'MIN', $fields, $values );
    }

    /**
     * Build a concatenation list to feed into a SQL query
     *
     * @param string[] $stringList
     * @return string
     */
    public function buildConcat( $stringList ) {
        return '(' . implode( ') || (', $stringList ) . ')';
    }

    /**
     * @param string[] $sqls
     * @param bool $all Whether to "UNION ALL" or not
     * @param array $options Query options, will be ignored in Sqlite
     * @return string
     */
    public function unionQueries( $sqls, $all, $options = [] ) {
        $glue = $all ? ' UNION ALL ' : ' UNION ';

        return implode( $glue, $sqls );
    }

    /**
     * @return bool
     */
    public function unionSupportsOrderAndLimit() {
        return false;
    }

    public function buildSubstring( $input, $startPosition, $length = null ) {
        $this->assertBuildSubstringParams( $startPosition, $length );
        $params = [ $input, $startPosition ];
        if ( $length !== null ) {
            $params[] = $length;
        }
        return 'SUBSTR(' . implode( ',', $params ) . ')';
    }

    /**
     * @param string $field Field or column to cast
     * @return string
     * @since 1.28
     */
    public function buildStringCast( $field ) {
        return 'CAST ( ' . $field . ' AS TEXT )';
    }

    public function tableName( string $name, $format = 'quoted' ) {
        if ( preg_match( '/^sqlite_[a-z_]+$/', $name ) ) {
            // Such names are reserved for internal SQLite tables
            return $name;
        }

        return parent::tableName( $name, $format );
    }

    protected function makeSelectOptions( array $options ) {
        // Remove problematic options that the base implementation converts to SQL
        foreach ( $options as $k => $v ) {
            if ( is_numeric( $k ) && ( $v === 'FOR UPDATE' || $v === 'LOCK IN SHARE MODE' ) ) {
                $options[$k] = '';
            }
        }

        return parent::makeSelectOptions( $options );
    }

    public function buildGroupConcatField(
        $delim, $table, $field, $conds = '', $join_conds = []
    ) {
        $fld = "group_concat($field," . $this->quoter->addQuotes( $delim ) . ')';

        return '(' . $this->selectSQLText( $table, $fld, $conds, null, [], $join_conds ) . ')';
    }

    protected function makeInsertNonConflictingVerbAndOptions() {
        return [ 'INSERT OR IGNORE INTO', '' ];
    }

    /**
     * @param array $options
     * @return array
     */
    protected function makeUpdateOptionsArray( $options ) {
        $options = parent::makeUpdateOptionsArray( $options );
        $options = $this->rewriteIgnoreKeyword( $options );

        return $options;
    }

    /**
     * @param array $options
     * @return array
     */
    private function rewriteIgnoreKeyword( $options ) {
        # SQLite uses OR IGNORE not just IGNORE
        foreach ( $options as $k => $v ) {
            if ( $v == 'IGNORE' ) {
                $options[$k] = 'OR IGNORE';
            }
        }

        return $options;
    }

    public function dropTableSqlText( $table ) {
        // No CASCADE support; https://www.sqlite.org/lang_droptable.html
        return "DROP TABLE " . $this->tableName( $table );
    }

    public function isTransactableQuery( Query $sql ) {
        return parent::isTransactableQuery( $sql ) && !in_array(
                $sql->getVerb(),
                [ 'ATTACH', 'PRAGMA' ],
                true
            );
    }
}