Ticket #30006: extract_wpdb_API.patch

src/wp-includes/wp-db-api.php

@@ +1 @@
+<?php
+/**
+ * WordPress DB API Class
+ *
+ * @since X4.2
+ * @package WordPress
+ * @subpackage Database
+ */
+
+/**
+ * WordPress Database API
+ *
+ * This class is a collection of low level methods for accessing the database without taking WordPress into account.
+ * All code that requires a different approach according to the currently used API should be put here too.
+ *
+ * api_*    methods provide a  generic interface to API functions that        have corresponding functionality.
+ * db_*     methods provide a specific interface to API functions that do not have corresponding functionality.
+ * mysqli_* methods provide a doctored access to mysqli_* functions.
+ * mysql_*  methods provide a doctored access to mysql_*  functions.
+ *
+ * @since X4.2
+ * @package WordPress
+ * @subpackage Database
+ */
+class wpdb_API {
+
+        /**
+         * API Name
+         *
+         * One of these two values:
+         * - 'mysqli'
+         * - 'mysql'
+         *
+         * @since X4.2
+         * @var string
+         */
+        protected $api = '';
+
+        /**
+         * Fallback State
+         *
+         * One of these four values:
+         *
+         * - 'impossible' (a fallback is not an option)
+         * - 'possible'   (can attempt a fallback)
+         * - 'success'    (a fallback allowed to connect)
+         * - 'failure'    (out of luck for connecting)
+         *
+         * @since X4.2
+         * @var string
+         */
+        protected $fallback;
+
+        /**
+         * Database Username
+         *
+         * @since 2.9.0
+         * @var string
+         */
+        protected $dbuser;
+
+        /**
+         * Database Password
+         *
+         * @since 3.1.0
+         * @var string
+         */
+        protected $dbpassword;
+
+        /**
+         * Database Name
+         *
+         * @since 3.1.0
+         * @var string
+         */
+        protected $dbname;
+
+        /**
+         * Database Host
+         *
+         * @since 3.1.0
+         * @var string
+         */
+        protected $dbhost;
+
+        /**
+         * Database Handle
+         *
+         * @since 0.71
+         * @var string
+         */
+        protected $dbh = null;
+
+        /**
+         * Store connection data.
+         *
+         * @param string $dbuser     MySQL database user
+         * @param string $dbpassword MySQL database password
+         * @param string $dbname     MySQL database name
+         * @param string $dbhost     MySQL database host
+         */
+        protected function __construct( $dbuser, $dbpassword, $dbname, $dbhost ) {
+                $this->dbuser     = $dbuser;
+                $this->dbpassword = $dbpassword;
+                $this->dbname     = $dbname;
+                $this->dbhost     = $dbhost;
+
+                $this->init_correspondence();
+                $this->init_api_to_use();
+        }
+
+        /**
+         * Detect the API to use
+         *
+         * @since X4.2
+         */
+        protected function init_api_to_use() {
+                $got_mysqli  = function_exists( 'mysqli_connect' );
+                $got_mysql   = function_exists( 'mysql_connect' );
+                $not_mysql   = defined( 'WP_USE_EXT_MYSQL' ) && ! WP_USE_EXT_MYSQL;
+                $PHP_5_5_min = version_compare( phpversion(), '5.5', '>=' );
+                $core_dev    = false !== strpos( $GLOBALS['wp_version'], '-' );
+
+                $this->api = $got_mysqli && ( $not_mysql || $PHP_5_5_min || ! $got_mysql || $core_dev )
+                        ? 'mysqli'
+                        : 'mysql';
+
+                $this->fallback = ( $this->api == 'mysqli' ) && ! $not_mysql && $got_mysql
+                        ? 'possible'
+                        : 'impossible';
+        }
+
+        /**
+         * These mysql_* functions and mysqli_* counterparts have the same parameters.
+         * The value has no meaning, we only use the key.
+         *
+         * @since X4.2
+         * @var array
+         */
+        private $same_arguments;
+
+        /**
+         * These mysql_* functions have parameters in a certain order, mysqli_* counterparts have them in another order.
+         * The value has no meaning, we only use the key.
+         *
+         * @since X4.2
+         * @var array
+         */
+        private $swapped_arguments;
+
+        /**
+         * These mysql_* functions have some parameters, mysqli_* counterparts have some other.
+         * The value is the number of same initial parameters.
+         *
+         * @since X4.2
+         * @var array
+         */
+        private $different_arguments;
+
+        /**
+         * These mysql_* functions exist, mysqli_* counterparts do not.
+         * The value has no meaning, we only use the key.
+         *
+         * @since X4.2
+         * @var array
+         */
+        private $defunct_functions;
+
+        /**
+         * Categorize mysql_* and mysqli_* functions.
+         *
+         * @since X4.2
+         */
+        protected function init_correspondence() {
+                // these arrays use keys for speed (isset VS in_array)
+
+                $this->same_arguments = array_flip( explode( ' ', 'affected_rows client_encoding close data_seek errno error'
+                        . ' fetch_array fetch_assoc fetch_field fetch_lengths fetch_object fetch_row field_seek free_result'
+                        . ' get_client_info get_host_info get_proto_info get_server_info info insert_id num_rows ping stat'
+                        . ' thread_id' ) );
+                        // mysql_fetch_field accepts one additional parameter, but mostly useless
+                        // mysqli_get_client_info accepts one additional parameter
+
+                $this->swapped_arguments = array_flip( explode( ' ', 'query real_escape_string select_db set_charset' ) );
+                        // mysqli_query accepts an additional parameter
+
+                // use db_connect instead
+                $this->different_arguments = array( 'connect' => 3 );
+                        // mysql additionally accepts $new_link, $client_flags; mysqli additionally accepts $dbname, $port, $socket
+
+                // if needed, these functions should be implemented along the lines of what done for connect in db_connect
+                $this->defunct_functions = array_flip( explode( ' ', 'create_db db_name db_query drop_db escape_string'
+                        . ' field_flags field_len field_name field_table field_type list_dbs list_fields list_processes list_tables'
+                        . ' num_fields pconnect result tablename unbuffered_query' ) );
+                        // mysql_escape_string highly discouraged, mysqli_escape_string alias of mysqli_real_escape_string
+                        // mysql_result is a function, mysqli_result is a class
+        }
+
+        /**
+         * Extract the term from $name.
+         *
+         * Example:
+         *
+         *    api_term('mysqli_close') == 'close';  // true
+         *    api_term('mysql_close')  == 'close';  // true
+         *    api_term('close')        == 'close';  // true
+         *
+         * @since X4.2
+         * @param  string $name The name of an API function
+         * @return string       The term contained in $name
+         */
+        protected function api_term($name) {
+                $result = $name;
+                if (strpos($name, $this->api . '_') === 0) {
+                        $result = substr($name, strlen($this->api . '_'));
+                }
+                return $result;
+        }
+
+        /**
+         * Reorder arguments of mysqli_* functions when needed for calling mysql_* counterparts.
+         *
+         * @since X4.2
+         * @param  string $name The mysqli_* function
+         * @param  array  $args The arguments of the mysqli_* function
+         * @return mixed        The arguments of the corresponding mysql_* function
+         * @throws Exception
+         */
+        protected function api_args($name, $args) {
+                // when using mysqli we can short-circuit right here
+                if ( 'mysqli' == $this->api ) {
+                        return $args;
+                }
+
+                $term = $this->api_term( $name );
+
+                if ( isset( $this->same_arguments[$term] ) ) {
+                        return $args;
+                }
+                if ( isset( $this->swapped_arguments[$term] ) ) {
+                        array_splice( $args, 0, 2, array( $args[1], $args[0] ));
+                        return $args;
+                }
+                if ( isset( $this->different_arguments[$term] ) ) {
+                        if ( count($args) <= $this->different_arguments[$term] ) {
+                                return $args;
+                        }
+                }
+                if ( isset( $this->defunct_functions[$term] ) ) {
+                        // we should never get here, except due to developer's misunderstanding
+                        throw new Exception('Expected a mysqli compatible function call.');
+                }
+                // we should never get here, except due to developer's misunderstanding
+                throw new Exception('Expected a mysql function call.');
+        }
+
+        /**
+         * Make an array with mysqli_* keys and either mysqli_* or mysql_* values, according to the current API.
+         *
+         * Use extract() to define API function variables with same name and arguments (in the same order).
+         *
+         * Example:
+         *
+         *    extract( $this->api_vars( 'close' ) );
+         *    // or extract( $this->api_vars( 'mysqli_close' ) );
+         *    // or extract( $this->api_vars( 'mysql_close' ) );
+         *    $mysqli_close( $this->dbh );
+         *
+         * Prefer mysqli_* names for making it easier to find where a given API is called.
+         *
+         * @since X4.2
+         * @var    array ... Names of API functions
+         * @return array     Array of variable names to API names
+         */
+        protected function api_vars() {
+                $names = func_get_args();
+                $result = array();
+                foreach ($names as $name) {
+                        $term = $this->api_term($name);
+                        $result["mysqli_$term"] = $this->api . '_' . $term;
+                }
+                return $result;
+        }
+
+        /**
+         * Call the current API function with the given name and additional arguments.
+         *
+         * This method allows to call API functions with the same name and arguments (possibly in a different order).
+         *
+         * Example:
+         *
+         *    $this->api_call( 'close' );
+         *    // or $this->api_call( 'mysqli_close' );
+         *    // or $this->api_call( 'mysql_close' );
+         *
+         * Prefer mysqli_* names for making it easier to find where a given API is called.
+         *
+         * @since X4.2
+         * @param  $name The name of the API function to call
+         * @param  ...   All the arguments for calling the API function
+         * @return mixed The value returned by the API call
+         */
+        public function api_call($name) {
+                $term = $this->api_term($name);
+                $args = func_get_args();
+                array_shift($args); // discard $name
+                $args = $this->api_args($term, $args);
+                $name = $this->api . '_' . $term;
+                return call_user_func_array($name, $args);
+        }
+
+        /**
+         * Connect to the database using mysql
+         *
+         * @since X4.2
+         */
+        private function mysql_connect() {
+                /*
+                 * Deprecated in 3.9+ when using MySQLi. No equivalent
+                 * $new_link parameter exists for mysqli_* functions.
+                 */
+                $new_link = defined( 'MYSQL_NEW_LINK' ) ? MYSQL_NEW_LINK : true;
+                $client_flags = defined( 'MYSQL_CLIENT_FLAGS' ) ? MYSQL_CLIENT_FLAGS : 0;
+
+                if ( WP_DEBUG ) {
+                        $this->dbh = mysql_connect( $this->dbhost, $this->dbuser, $this->dbpassword, $new_link, $client_flags );
+                } else {
+                        $this->dbh = @mysql_connect( $this->dbhost, $this->dbuser, $this->dbpassword, $new_link, $client_flags );
+                }
+        }
+
+        /**
+         * Connect to the database using mysqli
+         *
+         * @since X4.2
+         */
+        private function mysqli_connect() {
+                $this->dbh = mysqli_init();
+
+                // mysqli_real_connect doesn't support the host param including a port or socket
+                // like mysql_connect does. This duplicates how mysql_connect detects a port and/or socket file.
+                $port = null;
+                $socket = null;
+                $host = $this->dbhost;
+                $port_or_socket = strstr( $host, ':' );
+                if ( ! empty( $port_or_socket ) ) {
+                        $host = substr( $host, 0, strpos( $host, ':' ) );
+                        $port_or_socket = substr( $port_or_socket, 1 );
+                        if ( 0 !== strpos( $port_or_socket, '/' ) ) {
+                                $port = intval( $port_or_socket );
+                                $maybe_socket = strstr( $port_or_socket, ':' );
+                                if ( ! empty( $maybe_socket ) ) {
+                                        $socket = substr( $maybe_socket, 1 );
+                                }
+                        } else {
+                                $socket = $port_or_socket;
+                        }
+                }
+
+                $client_flags = defined( 'MYSQL_CLIENT_FLAGS' ) ? MYSQL_CLIENT_FLAGS : 0;
+
+                if ( WP_DEBUG ) {
+                        mysqli_real_connect( $this->dbh, $host, $this->dbuser, $this->dbpassword, null, $port, $socket, $client_flags );
+                } else {
+                        @mysqli_real_connect( $this->dbh, $host, $this->dbuser, $this->dbpassword, null, $port, $socket, $client_flags );
+                }
+        }
+
+        /**
+         * Connect to the database using the current API.
+         * This method COULD change the current API from mysqli to mysql in case of a fallback.
+         *
+         * mysqli_connect works quite differently from mysql_connect: we need a specific method for each and a this one for
+         * orchestrating. Notice that (public) wpdb::db_connect() overrides (protected) wpdb_API::db_connect().
+         *
+         * @since X4.2
+         * @return boolean TRUE if connected
+         */
+        protected function db_connect() {
+                if ( 'mysqli' == $this->api ) {
+                        $this->mysqli_connect();
+
+                        if ( $this->dbh->connect_errno ) {
+                                $this->dbh = null;
+                                if ( 'possible' == $this->fallback ) {
+                                        $this->api = 'mysql';
+                                        $this->mysql_connect();
+                                        $this->fallback = $this->dbh ? 'success' : 'failure';
+                                }
+                        }
+                } else {
+                        $this->mysql_connect();
+                }
+
+                return (bool) $this->dbh;
+        }
+
+        /**
+         * List SQL modes.
+         *
+         * @since X4.2
+         * @return array The set of SQL modes
+         */
+        protected function db_modes() {
+                $result = array();
+
+                $res = $this->api_call( 'query', $this->dbh, 'SELECT @@SESSION.sql_mode' );
+                if ( empty( $res ) ) {
+                        return $result;
+                }
+
+                if ( 'mysqli' == $this->api ) {
+                        $modes_array = mysqli_fetch_array( $res );
+                        if ( empty( $modes_array[0] ) ) {
+                                return $result;
+                        }
+                        $modes_str = $modes_array[0];
+                } else {
+                        $modes_str = mysql_result( $res, 0 );
+                }
+                if ( empty( $modes_str ) ) {
+                        return $result;
+                }
+
+                $result = explode( ',', $modes_str );
+                return $result;
+        }
+}

src/wp-includes/wp-db.php

@@ -1 +1 @@
 <?php
+
+require_once( ABSPATH . WPINC . '/wp-db-api.php' );
+
 /**
  * WordPress DB Class
  *
@@ -49 +52 @@
  * @subpackage Database
  * @since 0.71
  */
-class wpdb {
+class wpdb extends wpdb_API {
 
         /**
          * Whether to show SQL/DB errors.
@@ -465 +468 @@
         public $collate;
 
         /**
-         * Database Username
-         *
-         * @since 2.9.0
-         * @access protected
-         * @var string
-         */
-        protected $dbuser;
-
-        /**
-         * Database Password
-         *
-         * @since 3.1.0
-         * @access protected
-         * @var string
-         */
-        protected $dbpassword;
-
-        /**
-         * Database Name
-         *
-         * @since 3.1.0
-         * @access protected
-         * @var string
-         */
-        protected $dbname;
-
-        /**
-         * Database Host
-         *
-         * @since 3.1.0
-         * @access protected
-         * @var string
-         */
-        protected $dbhost;
-
-        /**
-         * Database Handle
-         *
-         * @since 0.71
-         * @access protected
-         * @var string
-         */
-        protected $dbh;
-
-        /**
          * A textual description of the last query/get_row/get_var call
          *
          * @since 3.0.0
@@ -545 +503 @@
         /**
          * Whether to use mysqli over mysql.
          *
+         * @deprecated
+         * @property-read
          * @since 3.9.0
          * @access private
          * @var bool
@@ -554 +514 @@
         /**
          * Whether we've managed to successfully connect at some point
          *
+         * @deprecated
+         * @property-read
          * @since 3.9.0
          * @access private
          * @var bool
@@ -581 +543 @@
                 if ( WP_DEBUG && WP_DEBUG_DISPLAY )
                         $this->show_errors();
 
-                /* Use ext/mysqli if it exists and:
-                 *  - WP_USE_EXT_MYSQL is defined as false, or
-                 *  - We are a development version of WordPress, or
-                 *  - We are running PHP 5.5 or greater, or
-                 *  - ext/mysql is not loaded.
-                 */
-                if ( function_exists( 'mysqli_connect' ) ) {
-                        if ( defined( 'WP_USE_EXT_MYSQL' ) ) {
-                                $this->use_mysqli = ! WP_USE_EXT_MYSQL;
-                        } elseif ( version_compare( phpversion(), '5.5', '>=' ) || ! function_exists( 'mysql_connect' ) ) {
-                                $this->use_mysqli = true;
-                        } elseif ( false !== strpos( $GLOBALS['wp_version'], '-' ) ) {
-                                $this->use_mysqli = true;
-                        }
-                }
-
                 $this->init_charset();
 
-                $this->dbuser = $dbuser;
-                $this->dbpassword = $dbpassword;
-                $this->dbname = $dbname;
-                $this->dbhost = $dbhost;
+                parent::__construct( $dbuser, $dbpassword, $dbname, $dbhost );
 
                 // wp-config.php creation will manually connect when ready.
                 if ( defined( 'WP_SETUP_CONFIG' ) ) {
@@ -632 +575 @@
          * @return mixed The private member
          */
         public function __get( $name ) {
-                if ( 'col_info' == $name )
+                if ( 'col_info' == $name ) {
                         $this->load_col_info();
+                } elseif ( 'use_mysqli' == $name ) {
+                        _deprecated_property( __CLASS__ . '::$' . $name, 'X4.2', "Try wpdb_API::api_call('mysqli_*')." );
+                        return 'mysqli' == $this->api;
+                } elseif ( 'has_connected' == $name ) {
+                        _deprecated_property( __CLASS__ . '::$' . $name, 'X4.2' );
+                        return (bool) $this->dbh;
+                }
 
                 return $this->$name;
         }
@@ -647 +597 @@
          * @param mixed  $value The value to set
          */
         public function __set( $name, $value ) {
+                if ( 'use_mysqli' == $name ) {
+                        _deprecated_property( __CLASS__ . '::$' . $name, 'X4.2', "Try wpdb_API::api_call('mysqli_*')." );
+                        return;
+                } elseif ( 'has_connected' == $name ) {
+                        _deprecated_property( __CLASS__ . '::$' . $name, 'X4.2' );
+                        return;
+                }
                 $this->$name = $value;
         }
 
@@ -660 +617 @@
          * @return bool If the member is set or not
          */
         public function __isset( $name ) {
+                if ( 'use_mysqli' == $name ) {
+                        _deprecated_property( __CLASS__ . '::$' . $name, 'X4.2', "Try wpdb_API::api_call('mysqli_*')." );
+                        return true;
+                } elseif ( 'has_connected' == $name ) {
+                        _deprecated_property( __CLASS__ . '::$' . $name, 'X4.2' );
+                        return true;
+                }
+
                 return isset( $this->$name );
         }
 
@@ -671 +636 @@
          * @param string $name  The private member to unset
          */
         public function __unset( $name ) {
+                if ( 'use_mysqli' == $name ) {
+                        _deprecated_property( __CLASS__ . '::$' . $name, 'X4.2', "Try wpdb_API::api_call('mysqli_*')." );
+                        return;
+                } elseif ( 'has_connected' == $name ) {
+                        _deprecated_property( __CLASS__ . '::$' . $name, 'X4.2' );
+                        return;
+                }
+
                 unset( $this->$name );
         }
 
@@ -709 +682 @@
                 if ( ! isset( $collate ) )
                         $collate = $this->collate;
                 if ( $this->has_cap( 'collation' ) && ! empty( $charset ) ) {
-                        if ( $this->use_mysqli ) {
-                                if ( function_exists( 'mysqli_set_charset' ) && $this->has_cap( 'set_charset' ) ) {
-                                        mysqli_set_charset( $dbh, $charset );
-                                } else {
-                                        $query = $this->prepare( 'SET NAMES %s', $charset );
-                                        if ( ! empty( $collate ) )
-                                                $query .= $this->prepare( ' COLLATE %s', $collate );
-                                        mysqli_query( $query, $dbh );
-                                }
+                        extract( $this->api_vars( 'set_charset' ) ); /** @var $mysqli_set_charset */
+
+                        if ( function_exists( $mysqli_set_charset ) && $this->has_cap( 'set_charset' ) ) {
+                                $this->api_call( 'mysqli_set_charset', $dbh, $charset );
                         } else {
-                                if ( function_exists( 'mysql_set_charset' ) && $this->has_cap( 'set_charset' ) ) {
-                                        mysql_set_charset( $charset, $dbh );
-                                } else {
-                                        $query = $this->prepare( 'SET NAMES %s', $charset );
-                                        if ( ! empty( $collate ) )
-                                                $query .= $this->prepare( ' COLLATE %s', $collate );
-                                        mysql_query( $query, $dbh );
-                                }
+                                $query = $this->prepare( 'SET NAMES %s', $charset );
+                                if ( ! empty( $collate ) )
+                                        $query .= $this->prepare( ' COLLATE %s', $collate );
+                                $this->api_call( 'mysqli_query', $dbh, $query );
                         }
                 }
         }
@@ -743 +707 @@
          */
         public function set_sql_mode( $modes = array() ) {
                 if ( empty( $modes ) ) {
-                        if ( $this->use_mysqli ) {
-                                $res = mysqli_query( $this->dbh, 'SELECT @@SESSION.sql_mode' );
-                        } else {
-                                $res = mysql_query( 'SELECT @@SESSION.sql_mode', $this->dbh );
-                        }
-
-                        if ( empty( $res ) ) {
-                                return;
-                        }
-
-                        if ( $this->use_mysqli ) {
-                                $modes_array = mysqli_fetch_array( $res );
-                                if ( empty( $modes_array[0] ) ) {
-                                        return;
-                                }
-                                $modes_str = $modes_array[0];
-                        } else {
-                                $modes_str = mysql_result( $res, 0 );
-                        }
-
-                        if ( empty( $modes_str ) ) {
-                                return;
-                        }
-
-                        $modes = explode( ',', $modes_str );
+                        $modes = $this->db_modes();
                 }
-
                 $modes = array_change_key_case( $modes, CASE_UPPER );
 
                 /**
@@ -782 +721 @@
                  * @param array $incompatible_modes An array of incompatible modes.
                  */
                 $incompatible_modes = (array) apply_filters( 'incompatible_sql_modes', $this->incompatible_modes );
-
-                foreach( $modes as $i => $mode ) {
-                        if ( in_array( $mode, $incompatible_modes ) ) {
-                                unset( $modes[ $i ] );
-                        }
-                }
+                $modes = array_diff($modes, $incompatible_modes);
 
                 $modes_str = implode( ',', $modes );
-
-                if ( $this->use_mysqli ) {
-                        mysqli_query( $this->dbh, "SET SESSION sql_mode='$modes_str'" );
-                } else {
-                        mysql_query( "SET SESSION sql_mode='$modes_str'", $this->dbh );
-                }
+                $this->api_call( 'mysqli_query', $this->dbh, "SET SESSION sql_mode='$modes_str'" );
         }
 
         /**
@@ -979 +908 @@
                 if ( is_null($dbh) )
                         $dbh = $this->dbh;
 
-                if ( $this->use_mysqli ) {
-                        $success = @mysqli_select_db( $dbh, $db );
-                } else {
-                        $success = @mysql_select_db( $db, $dbh );
-                }
+                $success = @$this->api_call('mysqli_select_db', $dbh, $db );
                 if ( ! $success ) {
                         $this->ready = false;
                         if ( ! did_action( 'template_redirect' ) ) {
@@ -1034 +959 @@
          */
         function _real_escape( $string ) {
                 if ( $this->dbh ) {
-                        if ( $this->use_mysqli ) {
-                                return mysqli_real_escape_string( $this->dbh, $string );
-                        } else {
-                                return mysql_real_escape_string( $string, $this->dbh );
-                        }
+                        return $this->api_call( 'mysqli_real_escape_string', $this->dbh, $string );
                 }
 
                 $class = get_class( $this );
@@ -1216 +1137 @@
                 global $EZSQL_ERROR;
 
                 if ( !$str ) {
-                        if ( $this->use_mysqli ) {
-                                $str = mysqli_error( $this->dbh );
-                        } else {
-                                $str = mysql_error( $this->dbh );
-                        }
+                        $str = $this->api_call( 'mysqli_error', $this->dbh );
                 }
                 $EZSQL_ERROR[] = array( 'query' => $this->last_query, 'error_str' => $str );
 
@@ -1325 +1242 @@
                 $this->last_error  = '';
 
                 if ( is_resource( $this->result ) ) {
-                        if ( $this->use_mysqli ) {
-                                mysqli_free_result( $this->result );
-                        } else {
-                                mysql_free_result( $this->result );
-                        }
+                        $this->api_call( 'mysqli_free_result', $this->result );
                 }
         }
 
@@ -1349 +1262 @@
 
                 $this->is_mysql = true;
 
-                /*
-                 * Deprecated in 3.9+ when using MySQLi. No equivalent
-                 * $new_link parameter exists for mysqli_* functions.
-                 */
-                $new_link = defined( 'MYSQL_NEW_LINK' ) ? MYSQL_NEW_LINK : true;
-                $client_flags = defined( 'MYSQL_CLIENT_FLAGS' ) ? MYSQL_CLIENT_FLAGS : 0;
-
-                if ( $this->use_mysqli ) {
-                        $this->dbh = mysqli_init();
-
-                        // mysqli_real_connect doesn't support the host param including a port or socket
-                        // like mysql_connect does. This duplicates how mysql_connect detects a port and/or socket file.
-                        $port = null;
-                        $socket = null;
-                        $host = $this->dbhost;
-                        $port_or_socket = strstr( $host, ':' );
-                        if ( ! empty( $port_or_socket ) ) {
-                                $host = substr( $host, 0, strpos( $host, ':' ) );
-                                $port_or_socket = substr( $port_or_socket, 1 );
-                                if ( 0 !== strpos( $port_or_socket, '/' ) ) {
-                                        $port = intval( $port_or_socket );
-                                        $maybe_socket = strstr( $port_or_socket, ':' );
-                                        if ( ! empty( $maybe_socket ) ) {
-                                                $socket = substr( $maybe_socket, 1 );
-                                        }
-                                } else {
-                                        $socket = $port_or_socket;
-                                }
-                        }
-
-                        if ( WP_DEBUG ) {
-                                mysqli_real_connect( $this->dbh, $host, $this->dbuser, $this->dbpassword, null, $port, $socket, $client_flags );
-                        } else {
-                                @mysqli_real_connect( $this->dbh, $host, $this->dbuser, $this->dbpassword, null, $port, $socket, $client_flags );
-                        }
-
-                        if ( $this->dbh->connect_errno ) {
-                                $this->dbh = null;
-
-                                /* It's possible ext/mysqli is misconfigured. Fall back to ext/mysql if:
-                                 *  - We haven't previously connected, and
-                                 *  - WP_USE_EXT_MYSQL isn't set to false, and
-                                 *  - ext/mysql is loaded.
-                                 */
-                                $attempt_fallback = true;
-
-                                if ( $this->has_connected ) {
-                                        $attempt_fallback = false;
-                                } else if ( defined( 'WP_USE_EXT_MYSQL' ) && ! WP_USE_EXT_MYSQL ) {
-                                        $attempt_fallback = false;
-                                } else if ( ! function_exists( 'mysql_connect' ) ) {
-                                        $attempt_fallback = false;
-                                }
-
-                                if ( $attempt_fallback ) {
-                                        $this->use_mysqli = false;
-                                        $this->db_connect();
-                                }
-                        }
-                } else {
-                        if ( WP_DEBUG ) {
-                                $this->dbh = mysql_connect( $this->dbhost, $this->dbuser, $this->dbpassword, $new_link, $client_flags );
-                        } else {
-                                $this->dbh = @mysql_connect( $this->dbhost, $this->dbuser, $this->dbpassword, $new_link, $client_flags );
-                        }
-                }
+                $result = parent::db_connect();
 
                 if ( ! $this->dbh && $allow_bail ) {
                         wp_load_translations_early();
@@ -1436 +1284 @@
 <p>If you're unsure what these terms mean you should probably contact your host. If you still need help you can always visit the <a href='https://wordpress.org/support/'>WordPress Support Forums</a>.</p>
 " ), htmlspecialchars( $this->dbhost, ENT_QUOTES ) ), 'db_connect_fail' );
 
-                        return false;
                 } else if ( $this->dbh ) {
-                        $this->has_connected = true;
+
                         $this->set_charset( $this->dbh );
                         $this->set_sql_mode();
                         $this->ready = true;
                         $this->select( $this->dbname, $this->dbh );
 
-                        return true;
                 }
 
-                return false;
+                return $result;
         }
 
         /**
@@ -1465 +1311 @@
          * @return bool True if the connection is up.
          */
         public function check_connection( $allow_bail = true ) {
-                if ( $this->use_mysqli ) {
-                        if ( @mysqli_ping( $this->dbh ) ) {
-                                return true;
-                        }
-                } else {
-                        if ( @mysql_ping( $this->dbh ) ) {
-                                return true;
-                        }
+                if ( @$this->api_call( 'mysqli_ping', $this->dbh ) ) {
+                        return true;
                 }
 
                 $error_reporting = false;
@@ -1527 +1367 @@
         }
 
         /**
+         * Called right before issuing the query, can be used when apply_filters( 'query', $query ) does not work.
+         *
+         * @since X4.2
+         * @param string $query
+         * @return string mixed
+         */
+        protected function filter_query($query) {
+                return $query;
+        }
+
+        /**
+         * Called on each results row right after fetching it.
+         *
+         * @since X4.2
+         * @param object $row
+         * @return object mixed
+         */
+        protected function filter_row($row) {
+                return $row;
+        }
+
+        /**
          * Perform a MySQL database query, using current database connection.
          *
          * More information can be found on the codex page.
@@ -1540 +1402 @@
                 if ( ! $this->ready )
                         return false;
 
+                extract( $this->api_vars( 'errno', 'error', 'affected_rows', 'insert_id', 'fetch_object' ) );
+                /**
+                 * @var $mysqli_errno
+                 * @var $mysqli_error
+                 * @var $mysqli_affected_rows
+                 * @var $mysqli_insert_id
+                 * @var $mysqli_fetch_object'
+                 */
+
                 /**
                  * Filter the database query.
                  *
@@ -1551 +1422 @@
                  * @param string $query Database query.
                  */
                 $query = apply_filters( 'query', $query );
+                $query = $this->filter_query($query);
 
                 $this->flush();
 
@@ -1563 +1435 @@
                 $this->_do_query( $query );
 
                 // MySQL server has gone away, try to reconnect
-                $mysql_errno = 0;
+                $errno = 0;
                 if ( ! empty( $this->dbh ) ) {
-                        if ( $this->use_mysqli ) {
-                                $mysql_errno = mysqli_errno( $this->dbh );
-                        } else {
-                                $mysql_errno = mysql_errno( $this->dbh );
-                        }
+                        $errno = $mysqli_errno( $this->dbh );
                 }
 
-                if ( empty( $this->dbh ) || 2006 == $mysql_errno ) {
+                if ( empty( $this->dbh ) || 2006 == $errno ) {
                         if ( $this->check_connection() ) {
                                 $this->_do_query( $query );
                         } else {
@@ -1582 +1450 @@
                 }
 
                 // If there is an error then take note of it..
-                if ( $this->use_mysqli ) {
-                        $this->last_error = mysqli_error( $this->dbh );
-                } else {
-                        $this->last_error = mysql_error( $this->dbh );
-                }
+                $this->last_error = $mysqli_error( $this->dbh );
 
                 if ( $this->last_error ) {
                         // Clear insert_id on a subsequent failed insert.
@@ -1600 +1464 @@
                 if ( preg_match( '/^\s*(create|alter|truncate|drop)\s/i', $query ) ) {
                         $return_val = $this->result;
                 } elseif ( preg_match( '/^\s*(insert|delete|update|replace)\s/i', $query ) ) {
-                        if ( $this->use_mysqli ) {
-                                $this->rows_affected = mysqli_affected_rows( $this->dbh );
-                        } else {
-                                $this->rows_affected = mysql_affected_rows( $this->dbh );
-                        }
+                        $this->rows_affected = $mysqli_affected_rows( $this->dbh );
                         // Take note of the insert_id
                         if ( preg_match( '/^\s*(insert|replace)\s/i', $query ) ) {
-                                if ( $this->use_mysqli ) {
-                                        $this->insert_id = mysqli_insert_id( $this->dbh );
-                                } else {
-                                        $this->insert_id = mysql_insert_id( $this->dbh );
-                                }
+                                $this->insert_id = $mysqli_insert_id( $this->dbh );
                         }
                         // Return number of rows affected
                         $return_val = $this->rows_affected;
                 } else {
                         $num_rows = 0;
-                        if ( $this->use_mysqli ) {
-                                while ( $row = @mysqli_fetch_object( $this->result ) ) {
-                                        $this->last_result[$num_rows] = $row;
-                                        $num_rows++;
-                                }
-                        } else {
-                                while ( $row = @mysql_fetch_object( $this->result ) ) {
-                                        $this->last_result[$num_rows] = $row;
-                                        $num_rows++;
-                                }
+                        while ( $row = @$mysqli_fetch_object( $this->result ) ) {
+                                $row = $this->filter_row($row);
+                                $this->last_result[$num_rows] = $row;
+                                $num_rows++;
                         }
 
                         // Log number of rows the query returned
@@ -1653 +1503 @@
                         $this->timer_start();
                 }
 
-                if ( $this->use_mysqli ) {
-                        $this->result = @mysqli_query( $this->dbh, $query );
-                } else {
-                        $this->result = @mysql_query( $query, $this->dbh );
-                }
+                $this->result = @$this->api_call( 'mysqli_query', $this->dbh, $query );
                 $this->num_queries++;
 
                 if ( defined( 'SAVEQUERIES' ) && SAVEQUERIES ) {
@@ -2001 +1847 @@
                 if ( $this->col_info )
                         return;
 
-                if ( $this->use_mysqli ) {
-                        for ( $i = 0; $i < @mysqli_num_fields( $this->result ); $i++ ) {
-                                $this->col_info[ $i ] = @mysqli_fetch_field( $this->result );
-                        }
-                } else {
-                        for ( $i = 0; $i < @mysql_num_fields( $this->result ); $i++ ) {
-                                $this->col_info[ $i ] = @mysql_fetch_field( $this->result, $i );
-                        }
+                extract( $this->api_vars( 'num_fields', 'fetch_field' ) ); /** @var $mysqli_num_fields *//** @var $mysqli_fetch_field */
+
+                for ( $i = 0; $i < @$mysqli_num_fields( $this->result ); $i++ ) {
+                        $this->col_info[ $i ] = @$mysqli_fetch_field( $this->result ); // no need to use field_offset here!
                 }
         }
 
@@ -2180 +2022 @@
          * @return false|string false on failure, version number on success
          */
         public function db_version() {
-                if ( $this->use_mysqli ) {
-                        $server_info = mysqli_get_server_info( $this->dbh );
-                } else {
-                        $server_info = mysql_get_server_info( $this->dbh );
-                }
+                $server_info = $this->api_call( 'mysqli_get_server_info', $this->dbh );
                 return preg_replace( '/[^0-9.].*/', '', $server_info );
         }
 }

tests/phpunit/tests/db.php

@@ -50 +50 @@
                 $var = $wpdb->get_var( "SELECT ID FROM $wpdb->users LIMIT 1" );
                 $this->assertGreaterThan( 0, $var );
 
-                if ( $wpdb->use_mysqli ) {
-                        mysqli_close( $wpdb->dbh );
-                } else {
-                        mysql_close( $wpdb->dbh );
-                }
+                $wpdb->api_call( 'close', $wpdb->dbh );
                 unset( $wpdb->dbh );
 
                 $var = $wpdb->get_var( "SELECT ID FROM $wpdb->users LIMIT 1" );
@@ -145 +141 @@
          * @dataProvider data_like_query
          * @param $data string The haystack, raw.
          * @param $like string The like phrase, raw.
-         * @param $result string The expected comparison result; '1' = true, '0' = false
+         * @param $result string The expected comparison result; '1' = true, '0' = false
          */
         function test_like_query( $data, $like, $result ) {
                 global $wpdb;
@@ -458 +454 @@
                 $this->assertEquals( $expected2, $wpdb->last_query );
                 $wpdb->suppress_errors( $suppress );
         }
+
+        /**
+         * @expectedDeprecated wpdb::$use_mysqli
+         * @expectedDeprecated wpdb::$has_connected
+         *
+         * @ticket
+         */
+        function test_deprecated_properties() {
+                global $wpdb;
+
+                $before = $wpdb->use_mysqli;
+                $wpdb->use_mysqli = ! $before;
+                $after = $wpdb->use_mysqli;
+                $this->assertEquals( $before, $after );  // readonly
+
+                $before = $wpdb->has_connected;
+                $wpdb->has_connected = ! $before;
+                $after = $wpdb->has_connected;
+                $this->assertEquals( $before, $after );  // readonly
+        }
 }