Add support for mysqli extension

DatabaseBase::factory()'s parameter array now takes an optional
'driver' variable to allow specifying a specific driver for the
database class if we support more than one.

This is so we can gracefully support mysql/mysqli as the former is
deprecated, but the concept could be extended to other databases
as well.

Bug: 45288
Co-Author: Chad Horohoe <chadh@wikimedia.org>
Change-Id: I6733fe21c4aa7443e409c5dfa7c789552b2b62b7

RELEASE-NOTES-1.22

@@ -326,6 +326,7 @@ production.
   database is created.
 * (bug 47191) Fixed "Column 'si_title' cannot be part of FULLTEXT index"
   MySQL error when installing using the binary character set option.
+* (bug 45288) Support mysqli PHP extension
 
 === API changes in 1.22 ===
 * (bug 25553) The JSON output formatter now leaves forward slashes unescaped

includes/AutoLoader.php

@@ -479,6 +479,7 @@ $wgAutoloadLocalClasses = array(
 	'DatabaseMssql' => 'includes/db/DatabaseMssql.php',
 	'DatabaseMysql' => 'includes/db/DatabaseMysql.php',
 	'DatabaseMysqlBase' => 'includes/db/DatabaseMysqlBase.php',
+	'DatabaseMysqli' => 'includes/db/DatabaseMysqli.php',
 	'DatabaseOracle' => 'includes/db/DatabaseOracle.php',
 	'DatabasePostgres' => 'includes/db/DatabasePostgres.php',
 	'DatabaseSqlite' => 'includes/db/DatabaseSqlite.php',

includes/db/Database.php

@@ -717,7 +717,7 @@ abstract class DatabaseBase implements IDatabase, DatabaseType {
 	/**
 	 * Given a DB type, construct the name of the appropriate child class of
 	 * DatabaseBase. This is designed to replace all of the manual stuff like:
-	 *	$class = 'Database' . ucfirst( strtolower( $type ) );
+	 *	$class = 'Database' . ucfirst( strtolower( $dbType ) );
 	 * as well as validate against the canonical list of DB types we have
 	 *
 	 * This factory function is mostly useful for when you need to connect to a
@@ -732,17 +732,43 @@ abstract class DatabaseBase implements IDatabase, DatabaseType {
 	 *
 	 * @param string $dbType A possible DB type
 	 * @param array $p An array of options to pass to the constructor.
-	 *    Valid options are: host, user, password, dbname, flags, tablePrefix
+	 *    Valid options are: host, user, password, dbname, flags, tablePrefix, driver
 	 * @return DatabaseBase subclass or null
 	 */
 	final public static function factory( $dbType, $p = array() ) {
 		$canonicalDBTypes = array(
-			'mysql', 'postgres', 'sqlite', 'oracle', 'mssql'
+			'mysql'    => array( 'mysqli', 'mysql' ),
+			'postgres' => array(),
+			'sqlite'   => array(),
+			'oracle'   => array(),
+			'mssql'    => array(),
 		);
-		$dbType = strtolower( $dbType );
-		$class = 'Database' . ucfirst( $dbType );
 
-		if ( in_array( $dbType, $canonicalDBTypes ) || ( class_exists( $class ) && is_subclass_of( $class, 'DatabaseBase' ) ) ) {
+		$dbType = strtolower( $dbType );
+		if ( isset( $canonicalDBTypes[$dbType] ) && $canonicalDBTypes[$dbType] ) {
+			$driver = isset( $p['driver'] ) ? $p['driver'] : null;
+			$possibleDrivers = $canonicalDBTypes[$dbType];
+			if ( $driver ) {
+				if ( in_array( $driver, $possibleDrivers ) ) {
+					$dbType = $driver;
+				} else {
+					throw new MWException( __METHOD__ .
+						" cannot construct Database with type '$dbType' and driver '$driver'" );
+				}
+			} else {
+				foreach ( $possibleDrivers as $posDriver ) {
+					if ( extension_loaded( $posDriver ) ) {
+						$dbType = $posDriver;
+						break;
+					}
+				}
+				throw new MWException( __METHOD__ .
+					" no viable database extension found for type '$dbType'" );
+			}
+		}
+
+		$class = 'Database' . ucfirst( $dbType );
+		if ( class_exists( $class ) && is_subclass_of( $class, 'DatabaseBase' ) ) {
 			return new $class(
 				isset( $p['host'] ) ? $p['host'] : false,
 				isset( $p['user'] ) ? $p['user'] : false,

includes/db/DatabaseMysqlBase.php

@@ -1006,7 +1006,7 @@ abstract class DatabaseMysqlBase extends DatabaseBase {
  */
 class MySQLField implements Field {
 	private $name, $tablename, $default, $max_length, $nullable,
-		$is_pk, $is_unique, $is_multiple, $is_key, $type;
+		$is_pk, $is_unique, $is_multiple, $is_key, $type, $binary;
 
 	function __construct( $info ) {
 		$this->name = $info->name;
@@ -1019,6 +1019,7 @@ class MySQLField implements Field {
 		$this->is_multiple = $info->multiple_key;
 		$this->is_key = ( $this->is_pk || $this->is_unique || $this->is_multiple );
 		$this->type = $info->type;
+		$this->binary = isset( $info->binary ) ? $info->binary : false;
 	}
 
 	/**
@@ -1066,6 +1067,10 @@ class MySQLField implements Field {
 	function isMultipleKey() {
 		return $this->is_multiple;
 	}
+
+	function isBinary() {
+		return $this->binary;
+	}
 }
 
 class MySQLMasterPos implements DBMasterPos {

includes/db/DatabaseMysqli.php

@@ -0,0 +1,194 @@
+<?php
+/**
+ * This is the MySQLi database abstraction layer.
+ *
+ * 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 Database
+ */
+
+/**
+ * Database abstraction object for PHP extension mysqli.
+ *
+ * @ingroup Database
+ * @since 1.22
+ * @see Database
+ */
+class DatabaseMysqli extends DatabaseMysqlBase {
+
+	/**
+	 * @param $sql string
+	 * @return resource
+	 */
+	protected function doQuery( $sql ) {
+		if ( $this->bufferResults() ) {
+			$ret = $this->mConn->query( $sql );
+		} else {
+			$ret = $this->mConn->query( $sql, MYSQLI_USE_RESULT );
+		}
+		return $ret;
+	}
+
+	protected function mysqlConnect( $realServer ) {
+		# Fail now
+		# Otherwise we get a suppressed fatal error, which is very hard to track down
+		if ( !function_exists( 'mysqli_init' ) ) {
+			throw new DBConnectionError( $this, "MySQLi functions missing,"
+				. " have you compiled PHP with the --with-mysqli option?\n" );
+		}
+
+		$connFlags = 0;
+		if ( $this->mFlags & DBO_SSL ) {
+			$connFlags |= MYSQLI_CLIENT_SSL;
+		}
+		if ( $this->mFlags & DBO_COMPRESS ) {
+			$connFlags |= MYSQLI_CLIENT_COMPRESS;
+		}
+		if ( $this->mFlags & DBO_PERSISTENT ) {
+			$realServer = 'p:' . $realServer;
+		}
+
+		$mysqli = mysqli_init();
+		$numAttempts = 2;
+
+		for ( $i = 0; $i < $numAttempts; $i++ ) {
+			if ( $i > 1 ) {
+				usleep( 1000 );
+			}
+			if ( $mysqli->real_connect( $realServer, $this->mUser,
+				$this->mPassword, $this->mDBname, null, null, $connFlags ) )
+			{
+				return $mysqli;
+			}
+		}
+
+		return false;
+	}
+
+	/**
+	 * @return bool
+	 */
+	protected function closeConnection() {
+		return $this->mConn->close();
+	}
+
+	/**
+	 * @return int
+	 */
+	function insertId() {
+		return $this->mConn->insert_id;
+	}
+
+	/**
+	 * @return int
+	 */
+	function lastErrno() {
+		if ( $this->mConn ) {
+			return $this->mConn->errno;
+		} else {
+			return mysqli_connect_errno();
+		}
+	}
+
+	/**
+	 * @return int
+	 */
+	function affectedRows() {
+		return $this->mConn->affected_rows;
+	}
+
+	/**
+	 * @param $db
+	 * @return bool
+	 */
+	function selectDB( $db ) {
+		$this->mDBname = $db;
+		return $this->mConn->select_db( $db );
+	}
+
+	/**
+	 * @return string
+	 */
+	function getServerVersion() {
+		return $this->mConn->server_info;
+	}
+
+	protected function mysqlFreeResult( $res ) {
+		$res->free_result();
+		return true;
+	}
+
+	protected function mysqlFetchObject( $res ) {
+		$object = $res->fetch_object();
+		if ( $object === null ) {
+			return false;
+		}
+		return $object;
+	}
+
+	protected function mysqlFetchArray( $res ) {
+		$array = $res->fetch_array();
+		if ( $array === null ) {
+			return false;
+		}
+		return $array;
+	}
+
+	protected function mysqlNumRows( $res ) {
+		return $res->num_rows;
+	}
+
+	protected function mysqlNumFields( $res ) {
+		return $res->field_count;
+	}
+
+	protected function mysqlFetchField( $res, $n ) {
+		$field = $res->fetch_field_direct( $n );
+		$field->not_null = $field->flags & MYSQLI_NOT_NULL_FLAG;
+		$field->primary_key = $field->flags & MYSQLI_PRI_KEY_FLAG;
+		$field->unique_key = $field->flags & MYSQLI_UNIQUE_KEY_FLAG;
+		$field->multiple_key = $field->flags & MYSQLI_MULTIPLE_KEY_FLAG;
+		$field->binary = $field->flags & MYSQLI_BINARY_FLAG;
+		return $field;
+	}
+
+	protected function mysqlFieldName( $res, $n ) {
+		$field = $res->fetch_field_direct( $n );
+		return $field->name;
+	}
+
+	protected function mysqlDataSeek( $res, $row ) {
+		return $res->data_seek( $row );
+	}
+
+	protected function mysqlError( $conn = null ) {
+		if ($conn === null) {
+			return mysqli_connect_error();
+		} else {
+			return $conn->error;
+		}
+	}
+
+	protected function mysqlRealEscapeString( $s ) {
+		return $this->mConn->real_escape_string( $s );
+	}
+
+	protected function mysqlPing() {
+		return $this->mConn->ping();
+	}
+
+}

includes/installer/MysqlUpdater.php

@@ -247,11 +247,8 @@ class MysqlUpdater extends DatabaseUpdater {
 			return true;
 		}
 
-		$tableName = $this->db->tableName( $table );
-		$res = $this->db->query( "SELECT $field FROM $tableName LIMIT 0", __METHOD__ );
-		$flags = explode( ' ', mysql_field_flags( $res->result, 0 ) );
-
-		if ( in_array( 'binary', $flags ) ) {
+		$fieldInfo = $this->db->fieldInfo( $table, $field );
+		if ( $fieldInfo->isBinary() ) {
 			$this->output( "...$table table has correct $field encoding.\n" );
 		} else {
 			$this->applyPatch( $patchFile, false, "Fixing $field encoding on $table table" );