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<?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\DBLanguageError;
use Wikimedia\Rdbms\Query;
/**
* @since 1.39
* @see ISQLPlatform
*/
class MySQLPlatform extends SQLPlatform {
protected function getIdentifierQuoteChar() {
return '`';
}
public function buildStringCast( $field ) {
return "CAST( $field AS BINARY )";
}
/**
* @param string $field Field or column to cast
* @return string
*/
public function buildIntegerCast( $field ) {
return 'CAST( ' . $field . ' AS SIGNED )';
}
protected function normalizeJoinType( string $joinType ) {
switch ( strtoupper( $joinType ) ) {
case 'STRAIGHT_JOIN':
case 'STRAIGHT JOIN':
return 'STRAIGHT_JOIN';
default:
return parent::normalizeJoinType( $joinType );
}
}
/**
* @param string $index
* @return string
*/
public function useIndexClause( $index ) {
return "FORCE INDEX (" . $this->indexName( $index ) . ")";
}
/**
* @param string $index
* @return string
*/
public function ignoreIndexClause( $index ) {
return "IGNORE INDEX (" . $this->indexName( $index ) . ")";
}
public function deleteJoinSqlText( $delTable, $joinTable, $delVar, $joinVar, $conds ) {
if ( !$conds ) {
throw new DBLanguageError( __METHOD__ . ' called with empty $conds' );
}
$delTable = $this->tableName( $delTable );
$joinTable = $this->tableName( $joinTable );
$sql = "DELETE $delTable FROM $delTable, $joinTable WHERE $delVar=$joinVar ";
if ( $conds != '*' ) {
$sql .= ' AND ' . $this->makeList( $conds, self::LIST_AND );
}
return $sql;
}
public function isTransactableQuery( Query $sql ) {
return parent::isTransactableQuery( $sql ) &&
// TODO: Use query verb
!preg_match( '/^SELECT\s+(GET|RELEASE|IS_FREE)_LOCK\(/', $sql->getSQL() );
}
public function buildExcludedValue( $column ) {
/* @see DatabaseMySQL::upsert() */
// Within "INSERT INTO ON DUPLICATE KEY UPDATE" statements:
// - MySQL>= 8.0.20 supports and prefers "VALUES ... AS".
// - MariaDB >= 10.3.3 supports and prefers VALUE().
// - Both support the old VALUES() function
// https://dev.mysql.com/doc/refman/8.0/en/insert-on-duplicate.html
// https://mariadb.com/kb/en/insert-on-duplicate-key-update/
return "VALUES($column)";
}
public function lockSQLText( $lockName, $timeout ) {
$encName = $this->quoter->addQuotes( $this->makeLockName( $lockName ) );
// Unlike NOW(), SYSDATE() gets the time at invocation rather than query start.
// The precision argument is silently ignored for MySQL < 5.6 and MariaDB < 5.3.
// https://dev.mysql.com/doc/refman/5.6/en/date-and-time-functions.html#function_sysdate
// https://dev.mysql.com/doc/refman/5.6/en/fractional-seconds.html
return "SELECT IF(GET_LOCK($encName,$timeout),UNIX_TIMESTAMP(SYSDATE(6)),NULL) AS acquired";
}
public function lockIsFreeSQLText( $lockName ) {
$encName = $this->quoter->addQuotes( $this->makeLockName( $lockName ) );
return "SELECT IS_FREE_LOCK($encName) AS unlocked";
}
public function unlockSQLText( $lockName ) {
$encName = $this->quoter->addQuotes( $this->makeLockName( $lockName ) );
return "SELECT RELEASE_LOCK($encName) AS released";
}
public function makeLockName( $lockName ) {
// https://dev.mysql.com/doc/refman/5.7/en/locking-functions.html#function_get-lock
// MySQL 5.7+ enforces a 64 char length limit.
return ( strlen( $lockName ) > 64 ) ? sha1( $lockName ) : $lockName;
}
}
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