wp/wp-includes/option.php
changeset 7 cf61fcea0001
parent 5 5e2f62d02dcd
child 9 177826044cd9
--- a/wp/wp-includes/option.php	Tue Jun 09 11:14:17 2015 +0000
+++ b/wp/wp-includes/option.php	Mon Oct 14 17:39:30 2019 +0200
@@ -7,7 +7,7 @@
  */
 
 /**
- * Retrieve option value based on name of option.
+ * Retrieves an option value based on an option name.
  *
  * If the option does not exist or does not have a value, then the return value
  * will be false. This is useful to check whether you need to install an option
@@ -16,10 +16,15 @@
  *
  * If the option was serialized then it will be unserialized when it is returned.
  *
+ * Any scalar values will be returned as strings. You may coerce the return type of
+ * a given option by registering an {@see 'option_$option'} filter callback.
+ *
  * @since 1.5.0
  *
- * @param string $option Name of option to retrieve. Expected to not be SQL-escaped.
- * @param mixed $default Optional. Default value to return if the option does not exist.
+ * @global wpdb $wpdb WordPress database abstraction object.
+ *
+ * @param string $option  Name of option to retrieve. Expected to not be SQL-escaped.
+ * @param mixed  $default Optional. Default value to return if the option does not exist.
  * @return mixed Value set for the option.
  */
 function get_option( $option, $default = false ) {
@@ -30,7 +35,7 @@
 		return false;
 
 	/**
-	 * Filter the value of an existing option before it is retrieved.
+	 * Filters the value of an existing option before it is retrieved.
 	 *
 	 * The dynamic portion of the hook name, `$option`, refers to the option name.
 	 *
@@ -38,32 +43,48 @@
 	 * the option value, returning the passed value instead.
 	 *
 	 * @since 1.5.0
+	 * @since 4.4.0 The `$option` parameter was added.
+	 * @since 4.9.0 The `$default` parameter was added.
 	 *
-	 * @param bool|mixed $pre_option Value to return instead of the option value.
-	 *                               Default false to skip it.
+	 *
+	 * @param bool|mixed $pre_option The value to return instead of the option value. This differs from
+	 *                               `$default`, which is used as the fallback value in the event the option
+	 *                               doesn't exist elsewhere in get_option(). Default false (to skip past the
+	 *                               short-circuit).
+	 * @param string     $option     Option name.
+	 * @param mixed      $default    The fallback value to return if the option does not exist.
+	 *                               Default is false.
 	 */
-	$pre = apply_filters( 'pre_option_' . $option, false );
+	$pre = apply_filters( "pre_option_{$option}", false, $option, $default );
+
 	if ( false !== $pre )
 		return $pre;
 
 	if ( defined( 'WP_SETUP_CONFIG' ) )
 		return false;
 
-	if ( ! defined( 'WP_INSTALLING' ) ) {
+	// Distinguish between `false` as a default, and not passing one.
+	$passed_default = func_num_args() > 1;
+
+	if ( ! wp_installing() ) {
 		// prevent non-existent options from triggering multiple queries
 		$notoptions = wp_cache_get( 'notoptions', 'options' );
 		if ( isset( $notoptions[ $option ] ) ) {
 			/**
-			 * Filter the default value for an option.
+			 * Filters the default value for an option.
 			 *
 			 * The dynamic portion of the hook name, `$option`, refers to the option name.
 			 *
 			 * @since 3.4.0
+			 * @since 4.4.0 The `$option` parameter was added.
+			 * @since 4.7.0 The `$passed_default` parameter was added to distinguish between a `false` value and the default parameter value.
 			 *
-			 * @param mixed $default The default value to return if the option does not exist
-			 *                       in the database.
+			 * @param mixed  $default The default value to return if the option does not exist
+			 *                        in the database.
+			 * @param string $option  Option name.
+			 * @param bool   $passed_default Was `get_option()` passed a default value?
 			 */
-			return apply_filters( 'default_option_' . $option, $default );
+			return apply_filters( "default_option_{$option}", $default, $option, $passed_default );
 		}
 
 		$alloptions = wp_load_alloptions();
@@ -81,11 +102,14 @@
 					$value = $row->option_value;
 					wp_cache_add( $option, $value, 'options' );
 				} else { // option does not exist, so we must cache its non-existence
+					if ( ! is_array( $notoptions ) ) {
+						 $notoptions = array();
+					}
 					$notoptions[$option] = true;
 					wp_cache_set( 'notoptions', $notoptions, 'options' );
 
 					/** This filter is documented in wp-includes/option.php */
-					return apply_filters( 'default_option_' . $option, $default );
+					return apply_filters( "default_option_{$option}", $default, $option, $passed_default );
 				}
 			}
 		}
@@ -97,7 +121,7 @@
 			$value = $row->option_value;
 		} else {
 			/** This filter is documented in wp-includes/option.php */
-			return apply_filters( 'default_option_' . $option, $default );
+			return apply_filters( "default_option_{$option}", $default, $option, $passed_default );
 		}
 	}
 
@@ -109,17 +133,19 @@
 		$value = untrailingslashit( $value );
 
 	/**
-	 * Filter the value of an existing option.
+	 * Filters the value of an existing option.
 	 *
 	 * The dynamic portion of the hook name, `$option`, refers to the option name.
 	 *
 	 * @since 1.5.0 As 'option_' . $setting
 	 * @since 3.0.0
+	 * @since 4.4.0 The `$option` parameter was added.
 	 *
-	 * @param mixed $value Value of the option. If stored serialized, it will be
-	 *                     unserialized prior to being returned.
+	 * @param mixed  $value  Value of the option. If stored serialized, it will be
+	 *                       unserialized prior to being returned.
+	 * @param string $option Option name.
 	 */
-	return apply_filters( 'option_' . $option, maybe_unserialize( $value ) );
+	return apply_filters( "option_{$option}", maybe_unserialize( $value ), $option );
 }
 
 /**
@@ -153,30 +179,52 @@
  *
  * @since 2.2.0
  *
+ * @global wpdb $wpdb WordPress database abstraction object.
+ *
  * @return array List of all options.
  */
 function wp_load_alloptions() {
 	global $wpdb;
 
-	if ( !defined( 'WP_INSTALLING' ) || !is_multisite() )
+	if ( ! wp_installing() || ! is_multisite() ) {
 		$alloptions = wp_cache_get( 'alloptions', 'options' );
-	else
+	} else {
 		$alloptions = false;
+	}
 
-	if ( !$alloptions ) {
+	if ( ! $alloptions ) {
 		$suppress = $wpdb->suppress_errors();
-		if ( !$alloptions_db = $wpdb->get_results( "SELECT option_name, option_value FROM $wpdb->options WHERE autoload = 'yes'" ) )
+		if ( ! $alloptions_db = $wpdb->get_results( "SELECT option_name, option_value FROM $wpdb->options WHERE autoload = 'yes'" ) ) {
 			$alloptions_db = $wpdb->get_results( "SELECT option_name, option_value FROM $wpdb->options" );
-		$wpdb->suppress_errors($suppress);
+		}
+		$wpdb->suppress_errors( $suppress );
+
 		$alloptions = array();
 		foreach ( (array) $alloptions_db as $o ) {
 			$alloptions[$o->option_name] = $o->option_value;
 		}
-		if ( !defined( 'WP_INSTALLING' ) || !is_multisite() )
+
+		if ( ! wp_installing() || ! is_multisite() ) {
+			/**
+			 * Filters all options before caching them.
+			 *
+			 * @since 4.9.0
+			 *
+			 * @param array $alloptions Array with all options.
+			 */
+			$alloptions = apply_filters( 'pre_cache_alloptions', $alloptions );
 			wp_cache_add( 'alloptions', $alloptions, 'options' );
+		}
 	}
 
-	return $alloptions;
+	/**
+	 * Filters all options after retrieving them.
+	 *
+	 * @since 4.9.0
+	 *
+	 * @param array $alloptions Array with all options.
+	 */
+	return apply_filters( 'alloptions', $alloptions );
 }
 
 /**
@@ -184,25 +232,27 @@
  *
  * @since 3.0.0
  *
- * @param int $site_id Optional site ID for which to query the options. Defaults to the current site.
+ * @global wpdb $wpdb WordPress database abstraction object.
+ *
+ * @param int $network_id Optional site ID for which to query the options. Defaults to the current site.
  */
-function wp_load_core_site_options( $site_id = null ) {
+function wp_load_core_site_options( $network_id = null ) {
 	global $wpdb;
 
-	if ( !is_multisite() || wp_using_ext_object_cache() || defined( 'WP_INSTALLING' ) )
+	if ( ! is_multisite() || wp_using_ext_object_cache() || wp_installing() )
 		return;
 
-	if ( empty($site_id) )
-		$site_id = $wpdb->siteid;
+	if ( empty($network_id) )
+		$network_id = get_current_network_id();
 
 	$core_options = array('site_name', 'siteurl', 'active_sitewide_plugins', '_site_transient_timeout_theme_roots', '_site_transient_theme_roots', 'site_admins', 'can_compress_scripts', 'global_terms_enabled', 'ms_files_rewriting' );
 
 	$core_options_in = "'" . implode("', '", $core_options) . "'";
-	$options = $wpdb->get_results( $wpdb->prepare("SELECT meta_key, meta_value FROM $wpdb->sitemeta WHERE meta_key IN ($core_options_in) AND site_id = %d", $site_id) );
+	$options = $wpdb->get_results( $wpdb->prepare( "SELECT meta_key, meta_value FROM $wpdb->sitemeta WHERE meta_key IN ($core_options_in) AND site_id = %d", $network_id ) );
 
 	foreach ( $options as $option ) {
 		$key = $option->meta_key;
-		$cache_key = "{$site_id}:$key";
+		$cache_key = "{$network_id}:$key";
 		$option->meta_value = maybe_unserialize( $option->meta_value );
 
 		wp_cache_set( $cache_key, $option->meta_value, 'site-options' );
@@ -216,19 +266,20 @@
  * it will be serialized before it is inserted into the database. Remember,
  * resources can not be serialized or added as an option.
  *
- * If the option does not exist, then the option will be added with the option
- * value, but you will not be able to set whether it is autoloaded. If you want
- * to set whether an option is autoloaded, then you need to use the add_option().
+ * If the option does not exist, then the option will be added with the option value,
+ * with an `$autoload` value of 'yes'.
  *
  * @since 1.0.0
  * @since 4.2.0 The `$autoload` parameter was added.
  *
+ * @global wpdb $wpdb WordPress database abstraction object.
+ *
  * @param string      $option   Option name. Expected to not be SQL-escaped.
  * @param mixed       $value    Option value. Must be serializable if non-scalar. Expected to not be SQL-escaped.
  * @param string|bool $autoload Optional. Whether to load the option when WordPress starts up. For existing options,
  *                              `$autoload` can only be updated using `update_option()` if `$value` is also changed.
- *                              Accepts 'yes' or true to enable, 'no' or false to disable. For non-existent options,
- *                              the default value is 'yes'.
+ *                              Accepts 'yes'|true to enable or 'no'|false to disable. For non-existent options,
+ *                              the default value is 'yes'. Default null.
  * @return bool False if value was not updated and true if value was updated.
  */
 function update_option( $option, $value, $autoload = null ) {
@@ -247,19 +298,21 @@
 	$old_value = get_option( $option );
 
 	/**
-	 * Filter a specific option before its value is (maybe) serialized and updated.
+	 * Filters a specific option before its value is (maybe) serialized and updated.
 	 *
 	 * The dynamic portion of the hook name, `$option`, refers to the option name.
 	 *
 	 * @since 2.6.0
+	 * @since 4.4.0 The `$option` parameter was added.
 	 *
-	 * @param mixed $value     The new, unserialized option value.
-	 * @param mixed $old_value The old option value.
+	 * @param mixed  $value     The new, unserialized option value.
+	 * @param mixed  $old_value The old option value.
+	 * @param string $option    Option name.
 	 */
-	$value = apply_filters( 'pre_update_option_' . $option, $value, $old_value );
+	$value = apply_filters( "pre_update_option_{$option}", $value, $old_value, $option );
 
 	/**
-	 * Filter an option before its value is (maybe) serialized and updated.
+	 * Filters an option before its value is (maybe) serialized and updated.
 	 *
 	 * @since 3.9.0
 	 *
@@ -269,12 +322,21 @@
 	 */
 	$value = apply_filters( 'pre_update_option', $value, $option, $old_value );
 
-	// If the new and old values are the same, no need to update.
-	if ( $value === $old_value )
+	/*
+	 * If the new and old values are the same, no need to update.
+	 *
+	 * Unserialized values will be adequate in most cases. If the unserialized
+	 * data differs, the (maybe) serialized data is checked to avoid
+	 * unnecessary database calls for otherwise identical object instances.
+	 *
+	 * See https://core.trac.wordpress.org/ticket/38903
+	 */
+	if ( $value === $old_value || maybe_serialize( $value ) === maybe_serialize( $old_value ) ) {
 		return false;
+	}
 
 	/** This filter is documented in wp-includes/option.php */
-	if ( apply_filters( 'default_option_' . $option, false ) === $old_value ) {
+	if ( apply_filters( "default_option_{$option}", false, $option, false ) === $old_value ) {
 		// Default setting for new options is 'yes'.
 		if ( null === $autoload ) {
 			$autoload = 'yes';
@@ -314,7 +376,7 @@
 		wp_cache_set( 'notoptions', $notoptions, 'options' );
 	}
 
-	if ( ! defined( 'WP_INSTALLING' ) ) {
+	if ( ! wp_installing() ) {
 		$alloptions = wp_load_alloptions();
 		if ( isset( $alloptions[$option] ) ) {
 			$alloptions[ $option ] = $serialized_value;
@@ -330,11 +392,13 @@
 	 * The dynamic portion of the hook name, `$option`, refers to the option name.
 	 *
 	 * @since 2.0.1
+	 * @since 4.4.0 The `$option` parameter was added.
 	 *
-	 * @param mixed $old_value The old option value.
-	 * @param mixed $value     The new option value.
+	 * @param mixed  $old_value The old option value.
+	 * @param mixed  $value     The new option value.
+	 * @param string $option    Option name.
 	 */
-	do_action( "update_option_{$option}", $old_value, $value );
+	do_action( "update_option_{$option}", $old_value, $value, $option );
 
 	/**
 	 * Fires after the value of an option has been successfully updated.
@@ -363,6 +427,8 @@
  *
  * @since 1.0.0
  *
+ * @global wpdb $wpdb WordPress database abstraction object.
+ *
  * @param string         $option      Name of option to add. Expected to not be SQL-escaped.
  * @param mixed          $value       Optional. Option value. Must be serializable if non-scalar. Expected to not be SQL-escaped.
  * @param string         $deprecated  Optional. Description. Not used anymore.
@@ -374,7 +440,7 @@
 	global $wpdb;
 
 	if ( !empty( $deprecated ) )
-		_deprecated_argument( __FUNCTION__, '2.3' );
+		_deprecated_argument( __FUNCTION__, '2.3.0' );
 
 	$option = trim($option);
 	if ( empty($option) )
@@ -391,7 +457,7 @@
 	$notoptions = wp_cache_get( 'notoptions', 'options' );
 	if ( !is_array( $notoptions ) || !isset( $notoptions[$option] ) )
 		/** This filter is documented in wp-includes/option.php */
-		if ( apply_filters( 'default_option_' . $option, false ) !== get_option( $option ) )
+		if ( apply_filters( "default_option_{$option}", false, $option, false ) !== get_option( $option ) )
 			return false;
 
 	$serialized_value = maybe_serialize( $value );
@@ -411,7 +477,7 @@
 	if ( ! $result )
 		return false;
 
-	if ( ! defined( 'WP_INSTALLING' ) ) {
+	if ( ! wp_installing() ) {
 		if ( 'yes' == $autoload ) {
 			$alloptions = wp_load_alloptions();
 			$alloptions[ $option ] = $serialized_value;
@@ -458,6 +524,8 @@
  *
  * @since 1.2.0
  *
+ * @global wpdb $wpdb WordPress database abstraction object.
+ *
  * @param string $option Name of option to remove. Expected to not be SQL-escaped.
  * @return bool True, if option is successfully deleted. False on failure.
  */
@@ -485,7 +553,7 @@
 	do_action( 'delete_option', $option );
 
 	$result = $wpdb->delete( $wpdb->options, array( 'option_name' => $option ) );
-	if ( ! defined( 'WP_INSTALLING' ) ) {
+	if ( ! wp_installing() ) {
 		if ( 'yes' == $row->autoload ) {
 			$alloptions = wp_load_alloptions();
 			if ( is_array( $alloptions ) && isset( $alloptions[$option] ) ) {
@@ -507,7 +575,7 @@
 		 *
 		 * @param string $option Name of the deleted option.
 		 */
-		do_action( "delete_option_$option", $option );
+		do_action( "delete_option_{$option}", $option );
 
 		/**
 		 * Fires after an option has been deleted.
@@ -541,7 +609,7 @@
 	 *
 	 * @param string $transient Transient name.
 	 */
-	do_action( 'delete_transient_' . $transient, $transient );
+	do_action( "delete_transient_{$transient}", $transient );
 
 	if ( wp_using_ext_object_cache() ) {
 		$result = wp_cache_delete( $transient, 'transient' );
@@ -581,8 +649,8 @@
  */
 function get_transient( $transient ) {
 
- 	/**
-	 * Filter the value of an existing transient.
+	/**
+	 * Filters the value of an existing transient.
 	 *
 	 * The dynamic portion of the hook name, `$transient`, refers to the transient name.
 	 *
@@ -590,12 +658,14 @@
 	 * of the transient, returning the passed value instead.
 	 *
 	 * @since 2.8.0
+	 * @since 4.4.0 The `$transient` parameter was added
 	 *
-	 * @param mixed $pre_transient The default value to return if the transient does not exist.
-	 *                             Any value other than false will short-circuit the retrieval
-	 *                             of the transient, and return the returned value.
+	 * @param mixed  $pre_transient The default value to return if the transient does not exist.
+	 *                              Any value other than false will short-circuit the retrieval
+	 *                              of the transient, and return the returned value.
+	 * @param string $transient     Transient name.
 	 */
-	$pre = apply_filters( 'pre_transient_' . $transient, false );
+	$pre = apply_filters( "pre_transient_{$transient}", false, $transient );
 	if ( false !== $pre )
 		return $pre;
 
@@ -603,12 +673,13 @@
 		$value = wp_cache_get( $transient, 'transient' );
 	} else {
 		$transient_option = '_transient_' . $transient;
-		if ( ! defined( 'WP_INSTALLING' ) ) {
+		if ( ! wp_installing() ) {
 			// If option is not in alloptions, it is not autoloaded and thus has a timeout
 			$alloptions = wp_load_alloptions();
 			if ( !isset( $alloptions[$transient_option] ) ) {
 				$transient_timeout = '_transient_timeout_' . $transient;
-				if ( get_option( $transient_timeout ) < time() ) {
+				$timeout = get_option( $transient_timeout );
+				if ( false !== $timeout && $timeout < time() ) {
 					delete_option( $transient_option  );
 					delete_option( $transient_timeout );
 					$value = false;
@@ -621,15 +692,17 @@
 	}
 
 	/**
-	 * Filter an existing transient's value.
+	 * Filters an existing transient's value.
 	 *
 	 * The dynamic portion of the hook name, `$transient`, refers to the transient name.
 	 *
 	 * @since 2.8.0
+	 * @since 4.4.0 The `$transient` parameter was added
 	 *
-	 * @param mixed $value Value of transient.
+	 * @param mixed  $value     Value of transient.
+	 * @param string $transient Transient name.
 	 */
-	return apply_filters( 'transient_' . $transient, $value );
+	return apply_filters( "transient_{$transient}", $value, $transient );
 }
 
 /**
@@ -641,10 +714,10 @@
  * @since 2.8.0
  *
  * @param string $transient  Transient name. Expected to not be SQL-escaped. Must be
- *                           45 characters or fewer in length.
+ *                           172 characters or fewer in length.
  * @param mixed  $value      Transient value. Must be serializable if non-scalar.
  *                           Expected to not be SQL-escaped.
- * @param int    $expiration Optional. Time until expiration in seconds. Default 0.
+ * @param int    $expiration Optional. Time until expiration in seconds. Default 0 (no expiration).
  * @return bool False if value was not set and true if value was set.
  */
 function set_transient( $transient, $value, $expiration = 0 ) {
@@ -652,46 +725,61 @@
 	$expiration = (int) $expiration;
 
 	/**
-	 * Filter a specific transient before its value is set.
+	 * Filters a specific transient before its value is set.
 	 *
 	 * The dynamic portion of the hook name, `$transient`, refers to the transient name.
 	 *
 	 * @since 3.0.0
-	 * @since 4.2.0 Added `$expiration` parameter.
+	 * @since 4.2.0 The `$expiration` parameter was added.
+	 * @since 4.4.0 The `$transient` parameter was added.
 	 *
-	 * @param mixed $value      New value of transient.
-	 * @param int   $expiration Time until expiration in seconds.
+	 * @param mixed  $value      New value of transient.
+	 * @param int    $expiration Time until expiration in seconds.
+	 * @param string $transient  Transient name.
 	 */
-	$value = apply_filters( 'pre_set_transient_' . $transient, $value, $expiration );
+	$value = apply_filters( "pre_set_transient_{$transient}", $value, $expiration, $transient );
+
+	/**
+	 * Filters the expiration for a transient before its value is set.
+	 *
+	 * The dynamic portion of the hook name, `$transient`, refers to the transient name.
+	 *
+	 * @since 4.4.0
+	 *
+	 * @param int    $expiration Time until expiration in seconds. Use 0 for no expiration.
+	 * @param mixed  $value      New value of transient.
+	 * @param string $transient  Transient name.
+	 */
+	$expiration = apply_filters( "expiration_of_transient_{$transient}", $expiration, $value, $transient );
 
 	if ( wp_using_ext_object_cache() ) {
 		$result = wp_cache_set( $transient, $value, 'transient', $expiration );
 	} else {
 		$transient_timeout = '_transient_timeout_' . $transient;
-		$transient = '_transient_' . $transient;
-		if ( false === get_option( $transient ) ) {
+		$transient_option = '_transient_' . $transient;
+		if ( false === get_option( $transient_option ) ) {
 			$autoload = 'yes';
 			if ( $expiration ) {
 				$autoload = 'no';
 				add_option( $transient_timeout, time() + $expiration, '', 'no' );
 			}
-			$result = add_option( $transient, $value, '', $autoload );
+			$result = add_option( $transient_option, $value, '', $autoload );
 		} else {
 			// If expiration is requested, but the transient has no timeout option,
 			// delete, then re-create transient rather than update.
 			$update = true;
 			if ( $expiration ) {
 				if ( false === get_option( $transient_timeout ) ) {
-					delete_option( $transient );
+					delete_option( $transient_option );
 					add_option( $transient_timeout, time() + $expiration, '', 'no' );
-					$result = add_option( $transient, $value, '', 'no' );
+					$result = add_option( $transient_option, $value, '', 'no' );
 					$update = false;
 				} else {
 					update_option( $transient_timeout, time() + $expiration );
 				}
 			}
 			if ( $update ) {
-				$result = update_option( $transient, $value );
+				$result = update_option( $transient_option, $value );
 			}
 		}
 	}
@@ -704,20 +792,24 @@
 		 * The dynamic portion of the hook name, `$transient`, refers to the transient name.
 		 *
 		 * @since 3.0.0
+		 * @since 3.6.0 The `$value` and `$expiration` parameters were added.
+		 * @since 4.4.0 The `$transient` parameter was added.
 		 *
-		 * @param mixed $value      Transient value.
-		 * @param int   $expiration Time until expiration in seconds. Default 0.
+		 * @param mixed  $value      Transient value.
+		 * @param int    $expiration Time until expiration in seconds.
+		 * @param string $transient  The name of the transient.
 		 */
-		do_action( 'set_transient_' . $transient, $value, $expiration );
+		do_action( "set_transient_{$transient}", $value, $expiration, $transient );
 
 		/**
 		 * Fires after the value for a transient has been set.
 		 *
 		 * @since 3.0.0
+		 * @since 3.6.0 The `$value` and `$expiration` parameters were added.
 		 *
 		 * @param string $transient  The name of the transient.
 		 * @param mixed  $value      Transient value.
-		 * @param int    $expiration Time until expiration in seconds. Default 0.
+		 * @param int    $expiration Time until expiration in seconds.
 		 */
 		do_action( 'setted_transient', $transient, $value, $expiration );
 	}
@@ -725,6 +817,61 @@
 }
 
 /**
+ * Deletes all expired transients.
+ *
+ * The multi-table delete syntax is used to delete the transient record
+ * from table a, and the corresponding transient_timeout record from table b.
+ *
+ * @since 4.9.0
+ *
+ * @param bool $force_db Optional. Force cleanup to run against the database even when an external object cache is used.
+ */
+function delete_expired_transients( $force_db = false ) {
+	global $wpdb;
+
+	if ( ! $force_db && wp_using_ext_object_cache() ) {
+		return;
+	}
+
+	$wpdb->query( $wpdb->prepare(
+		"DELETE a, b FROM {$wpdb->options} a, {$wpdb->options} b
+			WHERE a.option_name LIKE %s
+			AND a.option_name NOT LIKE %s
+			AND b.option_name = CONCAT( '_transient_timeout_', SUBSTRING( a.option_name, 12 ) )
+			AND b.option_value < %d",
+		$wpdb->esc_like( '_transient_' ) . '%',
+		$wpdb->esc_like( '_transient_timeout_' ) . '%',
+		time()
+	) );
+
+	if ( ! is_multisite() ) {
+		// non-Multisite stores site transients in the options table.
+		$wpdb->query( $wpdb->prepare(
+			"DELETE a, b FROM {$wpdb->options} a, {$wpdb->options} b
+				WHERE a.option_name LIKE %s
+				AND a.option_name NOT LIKE %s
+				AND b.option_name = CONCAT( '_site_transient_timeout_', SUBSTRING( a.option_name, 17 ) )
+				AND b.option_value < %d",
+			$wpdb->esc_like( '_site_transient_' ) . '%',
+			$wpdb->esc_like( '_site_transient_timeout_' ) . '%',
+			time()
+		) );
+	} elseif ( is_multisite() && is_main_site() && is_main_network() ) {
+		// Multisite stores site transients in the sitemeta table.
+		$wpdb->query( $wpdb->prepare(
+			"DELETE a, b FROM {$wpdb->sitemeta} a, {$wpdb->sitemeta} b
+				WHERE a.meta_key LIKE %s
+				AND a.meta_key NOT LIKE %s
+				AND b.meta_key = CONCAT( '_site_transient_timeout_', SUBSTRING( a.meta_key, 17 ) )
+				AND b.meta_value < %d",
+			$wpdb->esc_like( '_site_transient_' ) . '%',
+			$wpdb->esc_like( '_site_transient_timeout_' ) . '%',
+			time()
+		) );
+	}
+}
+
+/**
  * Saves and restores user interface settings stored in a cookie.
  *
  * Checks if the current user-settings cookie is updated and stores it. When no
@@ -735,7 +882,7 @@
  */
 function wp_user_settings() {
 
-	if ( ! is_admin() || defined( 'DOING_AJAX' ) ) {
+	if ( ! is_admin() || wp_doing_ajax() ) {
 		return;
 	}
 
@@ -743,7 +890,7 @@
 		return;
 	}
 
-	if ( is_super_admin() && ! is_user_member_of_blog() ) {
+	if ( ! is_user_member_of_blog() ) {
 		return;
 	}
 
@@ -768,7 +915,7 @@
 	}
 
 	// The cookie is not set in the current browser or the saved value is newer.
-	$secure = ( 'https' === parse_url( site_url(), PHP_URL_SCHEME ) );
+	$secure = ( 'https' === parse_url( admin_url(), PHP_URL_SCHEME ) );
 	setcookie( 'wp-settings-' . $user_id, $settings, time() + YEAR_IN_SECONDS, SITECOOKIEPATH, null, $secure );
 	setcookie( 'wp-settings-time-' . $user_id, time(), time() + YEAR_IN_SECONDS, SITECOOKIEPATH, null, $secure );
 	$_COOKIE['wp-settings-' . $user_id] = $settings;
@@ -779,7 +926,7 @@
  *
  * @since 2.7.0
  *
- * @param string $name The name of the setting.
+ * @param string $name    The name of the setting.
  * @param string $default Optional default value to return when $name is not set.
  * @return mixed the last saved user setting or the default value/false if it doesn't exist.
  */
@@ -793,16 +940,16 @@
  * Add or update user interface setting.
  *
  * Both $name and $value can contain only ASCII letters, numbers and underscores.
+ *
  * This function has to be used before any output has started as it calls setcookie().
  *
  * @since 2.8.0
  *
- * @param string $name The name of the setting.
+ * @param string $name  The name of the setting.
  * @param string $value The value for the setting.
- * @return null|bool true if set successfully/false if not.
+ * @return bool|null True if set successfully, false if not. Null if the current user can't be established.
  */
 function set_user_setting( $name, $value ) {
-
 	if ( headers_sent() ) {
 		return false;
 	}
@@ -817,15 +964,15 @@
  * Delete user interface settings.
  *
  * Deleting settings would reset them to the defaults.
+ *
  * This function has to be used before any output has started as it calls setcookie().
  *
  * @since 2.7.0
  *
  * @param string $names The name or array of names of the setting to be deleted.
- * @return null|bool true if deleted successfully/false if not.
+ * @return bool|null True if deleted successfully, false if not. Null if the current user can't be established.
  */
 function delete_user_setting( $names ) {
-
 	if ( headers_sent() ) {
 		return false;
 	}
@@ -853,6 +1000,8 @@
  *
  * @since 2.7.0
  *
+ * @global array $_updated_user_settings
+ *
  * @return array the last saved user settings or empty array.
  */
 function get_all_user_settings() {
@@ -869,7 +1018,7 @@
 	$user_settings = array();
 
 	if ( isset( $_COOKIE['wp-settings-' . $user_id] ) ) {
-		$cookie = preg_replace( '/[^A-Za-z0-9=&_]/', '', $_COOKIE['wp-settings-' . $user_id] );
+		$cookie = preg_replace( '/[^A-Za-z0-9=&_-]/', '', $_COOKIE['wp-settings-' . $user_id] );
 
 		if ( strpos( $cookie, '=' ) ) { // '=' cannot be 1st char
 			parse_str( $cookie, $user_settings );
@@ -890,9 +1039,13 @@
  * Private. Set all user interface settings.
  *
  * @since 2.8.0
+ * @access private
  *
- * @param array $user_settings
- * @return null|bool
+ * @global array $_updated_user_settings
+ *
+ * @param array $user_settings User settings.
+ * @return bool|null False if the current user can't be found, null if the current
+ *                   user is not a super admin or a member of the site, otherwise true.
  */
 function wp_set_all_user_settings( $user_settings ) {
 	global $_updated_user_settings;
@@ -901,14 +1054,14 @@
 		return false;
 	}
 
-	if ( is_super_admin() && ! is_user_member_of_blog() ) {
+	if ( ! is_user_member_of_blog() ) {
 		return;
 	}
 
 	$settings = '';
 	foreach ( $user_settings as $name => $value ) {
-		$_name = preg_replace( '/[^A-Za-z0-9_]+/', '', $name );
-		$_value = preg_replace( '/[^A-Za-z0-9_]+/', '', $value );
+		$_name = preg_replace( '/[^A-Za-z0-9_-]+/', '', $name );
+		$_value = preg_replace( '/[^A-Za-z0-9_-]+/', '', $value );
 
 		if ( ! empty( $_name ) ) {
 			$settings .= $_name . '=' . $_value . '&';
@@ -939,22 +1092,102 @@
 }
 
 /**
- * Retrieve site option value based on name of option.
+ * Retrieve an option value for the current network based on name of option.
+ *
+ * @since 2.8.0
+ * @since 4.4.0 The `$use_cache` parameter was deprecated.
+ * @since 4.4.0 Modified into wrapper for get_network_option()
+ *
+ * @see get_network_option()
+ *
+ * @param string $option     Name of option to retrieve. Expected to not be SQL-escaped.
+ * @param mixed  $default    Optional value to return if option doesn't exist. Default false.
+ * @param bool   $deprecated Whether to use cache. Multisite only. Always set to true.
+ * @return mixed Value set for the option.
+ */
+function get_site_option( $option, $default = false, $deprecated = true ) {
+	return get_network_option( null, $option, $default );
+}
+
+/**
+ * Add a new option for the current network.
+ *
+ * Existing options will not be updated. Note that prior to 3.3 this wasn't the case.
  *
  * @since 2.8.0
+ * @since 4.4.0 Modified into wrapper for add_network_option()
+ *
+ * @see add_network_option()
+ *
+ * @param string $option Name of option to add. Expected to not be SQL-escaped.
+ * @param mixed  $value  Option value, can be anything. Expected to not be SQL-escaped.
+ * @return bool False if the option was not added. True if the option was added.
+ */
+function add_site_option( $option, $value ) {
+	return add_network_option( null, $option, $value );
+}
+
+/**
+ * Removes a option by name for the current network.
+ *
+ * @since 2.8.0
+ * @since 4.4.0 Modified into wrapper for delete_network_option()
+ *
+ * @see delete_network_option()
+ *
+ * @param string $option Name of option to remove. Expected to not be SQL-escaped.
+ * @return bool True, if succeed. False, if failure.
+ */
+function delete_site_option( $option ) {
+	return delete_network_option( null, $option );
+}
+
+/**
+ * Update the value of an option that was already added for the current network.
+ *
+ * @since 2.8.0
+ * @since 4.4.0 Modified into wrapper for update_network_option()
+ *
+ * @see update_network_option()
+ *
+ * @param string $option Name of option. Expected to not be SQL-escaped.
+ * @param mixed  $value  Option value. Expected to not be SQL-escaped.
+ * @return bool False if value was not updated. True if value was updated.
+ */
+function update_site_option( $option, $value ) {
+	return update_network_option( null, $option, $value );
+}
+
+/**
+ * Retrieve a network's option value based on the option name.
+ *
+ * @since 4.4.0
  *
  * @see get_option()
  *
- * @param string $option Name of option to retrieve. Expected to not be SQL-escaped.
- * @param mixed $default Optional value to return if option doesn't exist. Default false.
- * @param bool $use_cache Whether to use cache. Multisite only. Default true.
+ * @global wpdb $wpdb
+ *
+ * @param int      $network_id ID of the network. Can be null to default to the current network ID.
+ * @param string   $option     Name of option to retrieve. Expected to not be SQL-escaped.
+ * @param mixed    $default    Optional. Value to return if the option doesn't exist. Default false.
  * @return mixed Value set for the option.
  */
-function get_site_option( $option, $default = false, $use_cache = true ) {
+function get_network_option( $network_id, $option, $default = false ) {
 	global $wpdb;
 
+	if ( $network_id && ! is_numeric( $network_id ) ) {
+		return false;
+	}
+
+	$network_id = (int) $network_id;
+
+	// Fallback to the current network if a network ID is not specified.
+	if ( ! $network_id ) {
+		$network_id = get_current_network_id();
+	}
+
 	/**
-	 * Filter an existing site option before it is retrieved.
+	 * Filters an existing network option before it is retrieved.
 	 *
 	 * The dynamic portion of the hook name, `$option`, refers to the option name.
 	 *
@@ -963,45 +1196,58 @@
 	 *
 	 * @since 2.9.0 As 'pre_site_option_' . $key
 	 * @since 3.0.0
+	 * @since 4.4.0 The `$option` parameter was added.
+	 * @since 4.7.0 The `$network_id` parameter was added.
+	 * @since 4.9.0 The `$default` parameter was added.
 	 *
-	 * @param mixed $pre_option The default value to return if the option does not exist.
+	 * @param mixed  $pre_option The value to return instead of the option value. This differs from
+	 *                           `$default`, which is used as the fallback value in the event the
+	 *                           option doesn't exist elsewhere in get_network_option(). Default
+	 *                           is false (to skip past the short-circuit).
+	 * @param string $option     Option name.
+	 * @param int    $network_id ID of the network.
+	 * @param mixed  $default    The fallback value to return if the option does not exist.
+	 *                           Default is false.
 	 */
- 	$pre = apply_filters( 'pre_site_option_' . $option, false );
+	$pre = apply_filters( "pre_site_option_{$option}", false, $option, $network_id, $default );
 
- 	if ( false !== $pre )
- 		return $pre;
+	if ( false !== $pre ) {
+		return $pre;
+	}
 
 	// prevent non-existent options from triggering multiple queries
-	$notoptions_key = "{$wpdb->siteid}:notoptions";
+	$notoptions_key = "$network_id:notoptions";
 	$notoptions = wp_cache_get( $notoptions_key, 'site-options' );
 
-	if ( isset( $notoptions[$option] ) ) {
+	if ( isset( $notoptions[ $option ] ) ) {
 
 		/**
-		 * Filter a specific default site option.
+		 * Filters a specific default network option.
 		 *
 		 * The dynamic portion of the hook name, `$option`, refers to the option name.
 		 *
 		 * @since 3.4.0
+		 * @since 4.4.0 The `$option` parameter was added.
+		 * @since 4.7.0 The `$network_id` parameter was added.
 		 *
-		 * @param mixed $default The value to return if the site option does not exist
-		 *                       in the database.
+		 * @param mixed  $default    The value to return if the site option does not exist
+		 *                           in the database.
+		 * @param string $option     Option name.
+		 * @param int    $network_id ID of the network.
 		 */
-		return apply_filters( 'default_site_option_' . $option, $default );
+		return apply_filters( "default_site_option_{$option}", $default, $option, $network_id );
 	}
 
 	if ( ! is_multisite() ) {
-
 		/** This filter is documented in wp-includes/option.php */
-		$default = apply_filters( 'default_site_option_' . $option, $default );
-		$value = get_option($option, $default);
+		$default = apply_filters( 'default_site_option_' . $option, $default, $option, $network_id );
+		$value = get_option( $option, $default );
 	} else {
-		$cache_key = "{$wpdb->siteid}:$option";
-		if ( $use_cache )
-			$value = wp_cache_get($cache_key, 'site-options');
+		$cache_key = "$network_id:$option";
+		$value = wp_cache_get( $cache_key, 'site-options' );
 
-		if ( !isset($value) || (false === $value) ) {
-			$row = $wpdb->get_row( $wpdb->prepare("SELECT meta_value FROM $wpdb->sitemeta WHERE meta_key = %s AND site_id = %d", $option, $wpdb->siteid ) );
+		if ( ! isset( $value ) || false === $value ) {
+			$row = $wpdb->get_row( $wpdb->prepare( "SELECT meta_value FROM $wpdb->sitemeta WHERE meta_key = %s AND site_id = %d", $option, $network_id ) );
 
 			// Has to be get_row instead of get_var because of funkiness with 0, false, null values
 			if ( is_object( $row ) ) {
@@ -1009,85 +1255,113 @@
 				$value = maybe_unserialize( $value );
 				wp_cache_set( $cache_key, $value, 'site-options' );
 			} else {
-				$notoptions[$option] = true;
+				if ( ! is_array( $notoptions ) ) {
+					$notoptions = array();
+				}
+				$notoptions[ $option ] = true;
 				wp_cache_set( $notoptions_key, $notoptions, 'site-options' );
 
 				/** This filter is documented in wp-includes/option.php */
-				$value = apply_filters( 'default_site_option_' . $option, $default );
+				$value = apply_filters( 'default_site_option_' . $option, $default, $option, $network_id );
 			}
 		}
 	}
 
 	/**
-	 * Filter the value of an existing site option.
+	 * Filters the value of an existing network option.
 	 *
 	 * The dynamic portion of the hook name, `$option`, refers to the option name.
 	 *
 	 * @since 2.9.0 As 'site_option_' . $key
 	 * @since 3.0.0
+	 * @since 4.4.0 The `$option` parameter was added.
+	 * @since 4.7.0 The `$network_id` parameter was added.
 	 *
-	 * @param mixed $value Value of site option.
+	 * @param mixed  $value      Value of network option.
+	 * @param string $option     Option name.
+	 * @param int    $network_id ID of the network.
 	 */
- 	return apply_filters( 'site_option_' . $option, $value );
+	return apply_filters( "site_option_{$option}", $value, $option, $network_id );
 }
 
 /**
- * Add a new site option.
+ * Add a new network option.
  *
- * Existing options will not be updated. Note that prior to 3.3 this wasn't the case.
+ * Existing options will not be updated.
  *
- * @since 2.8.0
+ * @since 4.4.0
  *
  * @see add_option()
  *
- * @param string $option Name of option to add. Expected to not be SQL-escaped.
- * @param mixed $value Optional. Option value, can be anything. Expected to not be SQL-escaped.
+ * @global wpdb $wpdb
+ *
+ * @param int    $network_id ID of the network. Can be null to default to the current network ID.
+ * @param string $option     Name of option to add. Expected to not be SQL-escaped.
+ * @param mixed  $value      Option value, can be anything. Expected to not be SQL-escaped.
  * @return bool False if option was not added and true if option was added.
  */
-function add_site_option( $option, $value ) {
+function add_network_option( $network_id, $option, $value ) {
 	global $wpdb;
 
+	if ( $network_id && ! is_numeric( $network_id ) ) {
+		return false;
+	}
+
+	$network_id = (int) $network_id;
+
+	// Fallback to the current network if a network ID is not specified.
+	if ( ! $network_id ) {
+		$network_id = get_current_network_id();
+	}
+
 	wp_protect_special_option( $option );
 
 	/**
-	 * Filter the value of a specific site option before it is added.
+	 * Filters the value of a specific network option before it is added.
 	 *
 	 * The dynamic portion of the hook name, `$option`, refers to the option name.
 	 *
 	 * @since 2.9.0 As 'pre_add_site_option_' . $key
 	 * @since 3.0.0
+	 * @since 4.4.0 The `$option` parameter was added.
+	 * @since 4.7.0 The `$network_id` parameter was added.
 	 *
-	 * @param mixed $value Value of site option.
+	 * @param mixed  $value      Value of network option.
+	 * @param string $option     Option name.
+	 * @param int    $network_id ID of the network.
 	 */
-	$value = apply_filters( 'pre_add_site_option_' . $option, $value );
+	$value = apply_filters( "pre_add_site_option_{$option}", $value, $option, $network_id );
 
-	$notoptions_key = "{$wpdb->siteid}:notoptions";
+	$notoptions_key = "$network_id:notoptions";
 
-	if ( !is_multisite() ) {
-		$result = add_option( $option, $value );
+	if ( ! is_multisite() ) {
+		$result = add_option( $option, $value, '', 'no' );
 	} else {
-		$cache_key = "{$wpdb->siteid}:$option";
+		$cache_key = "$network_id:$option";
 
 		// Make sure the option doesn't already exist. We can check the 'notoptions' cache before we ask for a db query
 		$notoptions = wp_cache_get( $notoptions_key, 'site-options' );
-		if ( ! is_array( $notoptions ) || ! isset( $notoptions[$option] ) )
-			if ( false !== get_site_option( $option ) )
+		if ( ! is_array( $notoptions ) || ! isset( $notoptions[ $option ] ) ) {
+			if ( false !== get_network_option( $network_id, $option, false ) ) {
 				return false;
+			}
+		}
 
 		$value = sanitize_option( $option, $value );
 
 		$serialized_value = maybe_serialize( $value );
-		$result = $wpdb->insert( $wpdb->sitemeta, array('site_id' => $wpdb->siteid, 'meta_key' => $option, 'meta_value' => $serialized_value ) );
+		$result = $wpdb->insert( $wpdb->sitemeta, array( 'site_id'    => $network_id, 'meta_key'   => $option, 'meta_value' => $serialized_value ) );
 
-		if ( ! $result )
+		if ( ! $result ) {
 			return false;
+		}
 
 		wp_cache_set( $cache_key, $value, 'site-options' );
 
 		// This option exists now
 		$notoptions = wp_cache_get( $notoptions_key, 'site-options' ); // yes, again... we need it to be fresh
-		if ( is_array( $notoptions ) && isset( $notoptions[$option] ) ) {
-			unset( $notoptions[$option] );
+		if ( is_array( $notoptions ) && isset( $notoptions[ $option ] ) ) {
+			unset( $notoptions[ $option ] );
 			wp_cache_set( $notoptions_key, $notoptions, 'site-options' );
 		}
 	}
@@ -1095,151 +1369,199 @@
 	if ( $result ) {
 
 		/**
-		 * Fires after a specific site option has been successfully added.
+		 * Fires after a specific network option has been successfully added.
 		 *
 		 * The dynamic portion of the hook name, `$option`, refers to the option name.
 		 *
 		 * @since 2.9.0 As "add_site_option_{$key}"
 		 * @since 3.0.0
+		 * @since 4.7.0 The `$network_id` parameter was added.
 		 *
-		 * @param string $option Name of site option.
-		 * @param mixed  $value  Value of site option.
+		 * @param string $option     Name of the network option.
+		 * @param mixed  $value      Value of the network option.
+		 * @param int    $network_id ID of the network.
 		 */
-		do_action( "add_site_option_{$option}", $option, $value );
+		do_action( "add_site_option_{$option}", $option, $value, $network_id );
 
 		/**
-		 * Fires after a site option has been successfully added.
+		 * Fires after a network option has been successfully added.
 		 *
 		 * @since 3.0.0
+		 * @since 4.7.0 The `$network_id` parameter was added.
 		 *
-		 * @param string $option Name of site option.
-		 * @param mixed  $value  Value of site option.
+		 * @param string $option     Name of the network option.
+		 * @param mixed  $value      Value of the network option.
+		 * @param int    $network_id ID of the network.
 		 */
-		do_action( "add_site_option", $option, $value );
+		do_action( 'add_site_option', $option, $value, $network_id );
 
 		return true;
 	}
+
 	return false;
 }
 
 /**
- * Removes site option by name.
+ * Removes a network option by name.
  *
- * @since 2.8.0
+ * @since 4.4.0
  *
  * @see delete_option()
  *
- * @param string $option Name of option to remove. Expected to not be SQL-escaped.
+ * @global wpdb $wpdb
+ *
+ * @param int    $network_id ID of the network. Can be null to default to the current network ID.
+ * @param string $option     Name of option to remove. Expected to not be SQL-escaped.
  * @return bool True, if succeed. False, if failure.
  */
-function delete_site_option( $option ) {
+function delete_network_option( $network_id, $option ) {
 	global $wpdb;
 
-	// ms_protect_special_option( $option ); @todo
+	if ( $network_id && ! is_numeric( $network_id ) ) {
+		return false;
+	}
+
+	$network_id = (int) $network_id;
+
+	// Fallback to the current network if a network ID is not specified.
+	if ( ! $network_id ) {
+		$network_id = get_current_network_id();
+	}
 
 	/**
-	 * Fires immediately before a specific site option is deleted.
+	 * Fires immediately before a specific network option is deleted.
 	 *
 	 * The dynamic portion of the hook name, `$option`, refers to the option name.
 	 *
 	 * @since 3.0.0
+	 * @since 4.4.0 The `$option` parameter was added.
+	 * @since 4.7.0 The `$network_id` parameter was added.
+	 *
+	 * @param string $option     Option name.
+	 * @param int    $network_id ID of the network.
 	 */
-	do_action( 'pre_delete_site_option_' . $option );
+	do_action( "pre_delete_site_option_{$option}", $option, $network_id );
 
-	if ( !is_multisite() ) {
+	if ( ! is_multisite() ) {
 		$result = delete_option( $option );
 	} else {
-		$row = $wpdb->get_row( $wpdb->prepare( "SELECT meta_id FROM {$wpdb->sitemeta} WHERE meta_key = %s AND site_id = %d", $option, $wpdb->siteid ) );
-		if ( is_null( $row ) || !$row->meta_id )
+		$row = $wpdb->get_row( $wpdb->prepare( "SELECT meta_id FROM {$wpdb->sitemeta} WHERE meta_key = %s AND site_id = %d", $option, $network_id ) );
+		if ( is_null( $row ) || ! $row->meta_id ) {
 			return false;
-		$cache_key = "{$wpdb->siteid}:$option";
+		}
+		$cache_key = "$network_id:$option";
 		wp_cache_delete( $cache_key, 'site-options' );
 
-		$result = $wpdb->delete( $wpdb->sitemeta, array( 'meta_key' => $option, 'site_id' => $wpdb->siteid ) );
+		$result = $wpdb->delete( $wpdb->sitemeta, array( 'meta_key' => $option, 'site_id' => $network_id ) );
 	}
 
 	if ( $result ) {
 
 		/**
-		 * Fires after a specific site option has been deleted.
+		 * Fires after a specific network option has been deleted.
 		 *
 		 * The dynamic portion of the hook name, `$option`, refers to the option name.
 		 *
 		 * @since 2.9.0 As "delete_site_option_{$key}"
 		 * @since 3.0.0
+		 * @since 4.7.0 The `$network_id` parameter was added.
 		 *
-		 * @param string $option Name of the site option.
+		 * @param string $option     Name of the network option.
+		 * @param int    $network_id ID of the network.
 		 */
-		do_action( "delete_site_option_{$option}", $option );
+		do_action( "delete_site_option_{$option}", $option, $network_id );
 
 		/**
-		 * Fires after a site option has been deleted.
+		 * Fires after a network option has been deleted.
 		 *
 		 * @since 3.0.0
+		 * @since 4.7.0 The `$network_id` parameter was added.
 		 *
-		 * @param string $option Name of the site option.
+		 * @param string $option     Name of the network option.
+		 * @param int    $network_id ID of the network.
 		 */
-		do_action( "delete_site_option", $option );
+		do_action( 'delete_site_option', $option, $network_id );
 
 		return true;
 	}
+
 	return false;
 }
 
 /**
- * Update the value of a site option that was already added.
+ * Update the value of a network option that was already added.
  *
- * @since 2.8.0
+ * @since 4.4.0
  *
  * @see update_option()
  *
- * @param string $option Name of option. Expected to not be SQL-escaped.
- * @param mixed $value Option value. Expected to not be SQL-escaped.
+ * @global wpdb $wpdb
+ *
+ * @param int      $network_id ID of the network. Can be null to default to the current network ID.
+ * @param string   $option     Name of option. Expected to not be SQL-escaped.
+ * @param mixed    $value      Option value. Expected to not be SQL-escaped.
  * @return bool False if value was not updated and true if value was updated.
  */
-function update_site_option( $option, $value ) {
+function update_network_option( $network_id, $option, $value ) {
 	global $wpdb;
 
+	if ( $network_id && ! is_numeric( $network_id ) ) {
+		return false;
+	}
+
+	$network_id = (int) $network_id;
+
+	// Fallback to the current network if a network ID is not specified.
+	if ( ! $network_id ) {
+		$network_id = get_current_network_id();
+	}
+
 	wp_protect_special_option( $option );
 
-	$old_value = get_site_option( $option );
+	$old_value = get_network_option( $network_id, $option, false );
 
 	/**
-	 * Filter a specific site option before its value is updated.
+	 * Filters a specific network option before its value is updated.
 	 *
 	 * The dynamic portion of the hook name, `$option`, refers to the option name.
 	 *
 	 * @since 2.9.0 As 'pre_update_site_option_' . $key
 	 * @since 3.0.0
+	 * @since 4.4.0 The `$option` parameter was added.
+	 * @since 4.7.0 The `$network_id` parameter was added.
 	 *
-	 * @param mixed $value     New value of site option.
-	 * @param mixed $old_value Old value of site option.
+	 * @param mixed  $value      New value of the network option.
+	 * @param mixed  $old_value  Old value of the network option.
+	 * @param string $option     Option name.
+	 * @param int    $network_id ID of the network.
 	 */
-	$value = apply_filters( 'pre_update_site_option_' . $option, $value, $old_value );
+	$value = apply_filters( "pre_update_site_option_{$option}", $value, $old_value, $option, $network_id );
 
-	if ( $value === $old_value )
+	if ( $value === $old_value ) {
 		return false;
-
-	if ( false === $old_value )
-		return add_site_option( $option, $value );
+	}
 
-	$notoptions_key = "{$wpdb->siteid}:notoptions";
+	if ( false === $old_value ) {
+		return add_network_option( $network_id, $option, $value );
+	}
+
+	$notoptions_key = "$network_id:notoptions";
 	$notoptions = wp_cache_get( $notoptions_key, 'site-options' );
-	if ( is_array( $notoptions ) && isset( $notoptions[$option] ) ) {
-		unset( $notoptions[$option] );
+	if ( is_array( $notoptions ) && isset( $notoptions[ $option ] ) ) {
+		unset( $notoptions[ $option ] );
 		wp_cache_set( $notoptions_key, $notoptions, 'site-options' );
 	}
 
-	if ( !is_multisite() ) {
-		$result = update_option( $option, $value );
+	if ( ! is_multisite() ) {
+		$result = update_option( $option, $value, 'no' );
 	} else {
 		$value = sanitize_option( $option, $value );
 
 		$serialized_value = maybe_serialize( $value );
-		$result = $wpdb->update( $wpdb->sitemeta, array( 'meta_value' => $serialized_value ), array( 'site_id' => $wpdb->siteid, 'meta_key' => $option ) );
+		$result = $wpdb->update( $wpdb->sitemeta, array( 'meta_value' => $serialized_value ), array( 'site_id' => $network_id, 'meta_key' => $option ) );
 
 		if ( $result ) {
-			$cache_key = "{$wpdb->siteid}:$option";
+			$cache_key = "$network_id:$option";
 			wp_cache_set( $cache_key, $value, 'site-options' );
 		}
 	}
@@ -1247,32 +1569,37 @@
 	if ( $result ) {
 
 		/**
-		 * Fires after the value of a specific site option has been successfully updated.
+		 * Fires after the value of a specific network option has been successfully updated.
 		 *
 		 * The dynamic portion of the hook name, `$option`, refers to the option name.
 		 *
 		 * @since 2.9.0 As "update_site_option_{$key}"
 		 * @since 3.0.0
+		 * @since 4.7.0 The `$network_id` parameter was added.
 		 *
-		 * @param string $option    Name of site option.
-		 * @param mixed  $value     Current value of site option.
-		 * @param mixed  $old_value Old value of site option.
+		 * @param string $option     Name of the network option.
+		 * @param mixed  $value      Current value of the network option.
+		 * @param mixed  $old_value  Old value of the network option.
+		 * @param int    $network_id ID of the network.
 		 */
-		do_action( "update_site_option_{$option}", $option, $value, $old_value );
+		do_action( "update_site_option_{$option}", $option, $value, $old_value, $network_id );
 
 		/**
-		 * Fires after the value of a site option has been successfully updated.
+		 * Fires after the value of a network option has been successfully updated.
 		 *
 		 * @since 3.0.0
+		 * @since 4.7.0 The `$network_id` parameter was added.
 		 *
-		 * @param string $option    Name of site option.
-		 * @param mixed  $value     Current value of site option.
-		 * @param mixed  $old_value Old value of site option.
+		 * @param string $option     Name of the network option.
+		 * @param mixed  $value      Current value of the network option.
+		 * @param mixed  $old_value  Old value of the network option.
+		 * @param int    $network_id ID of the network.
 		 */
-		do_action( "update_site_option", $option, $value, $old_value );
+		do_action( 'update_site_option', $option, $value, $old_value, $network_id );
 
 		return true;
 	}
+
 	return false;
 }
 
@@ -1295,7 +1622,7 @@
 	 *
 	 * @param string $transient Transient name.
 	 */
-	do_action( 'delete_site_transient_' . $transient, $transient );
+	do_action( "delete_site_transient_{$transient}", $transient );
 
 	if ( wp_using_ext_object_cache() ) {
 		$result = wp_cache_delete( $transient, 'site-transient' );
@@ -1337,7 +1664,7 @@
 function get_site_transient( $transient ) {
 
 	/**
-	 * Filter the value of an existing site transient.
+	 * Filters the value of an existing site transient.
 	 *
 	 * The dynamic portion of the hook name, `$transient`, refers to the transient name.
 	 *
@@ -1345,12 +1672,14 @@
 	 * returning the passed value instead.
 	 *
 	 * @since 2.9.0
+	 * @since 4.4.0 The `$transient` parameter was added.
 	 *
-	 * @param mixed $pre_site_transient The default value to return if the site transient does not exist.
-	 *                                  Any value other than false will short-circuit the retrieval
-	 *                                  of the transient, and return the returned value.
+	 * @param mixed  $pre_site_transient The default value to return if the site transient does not exist.
+	 *                                   Any value other than false will short-circuit the retrieval
+	 *                                   of the transient, and return the returned value.
+	 * @param string $transient          Transient name.
 	 */
-	$pre = apply_filters( 'pre_site_transient_' . $transient, false );
+	$pre = apply_filters( "pre_site_transient_{$transient}", false, $transient );
 
 	if ( false !== $pre )
 		return $pre;
@@ -1376,15 +1705,17 @@
 	}
 
 	/**
-	 * Filter the value of an existing site transient.
+	 * Filters the value of an existing site transient.
 	 *
 	 * The dynamic portion of the hook name, `$transient`, refers to the transient name.
 	 *
 	 * @since 2.9.0
+	 * @since 4.4.0 The `$transient` parameter was added.
 	 *
-	 * @param mixed $value Value of site transient.
+	 * @param mixed  $value     Value of site transient.
+	 * @param string $transient Transient name.
 	 */
-	return apply_filters( 'site_transient_' . $transient, $value );
+	return apply_filters( "site_transient_{$transient}", $value, $transient );
 }
 
 /**
@@ -1398,26 +1729,41 @@
  * @see set_transient()
  *
  * @param string $transient  Transient name. Expected to not be SQL-escaped. Must be
- *                           40 characters or fewer in length.
+ *                           167 characters or fewer in length.
  * @param mixed  $value      Transient value. Expected to not be SQL-escaped.
- * @param int    $expiration Optional. Time until expiration in seconds. Default 0.
+ * @param int    $expiration Optional. Time until expiration in seconds. Default 0 (no expiration).
  * @return bool False if value was not set and true if value was set.
  */
 function set_site_transient( $transient, $value, $expiration = 0 ) {
 
 	/**
-	 * Filter the value of a specific site transient before it is set.
+	 * Filters the value of a specific site transient before it is set.
 	 *
 	 * The dynamic portion of the hook name, `$transient`, refers to the transient name.
 	 *
 	 * @since 3.0.0
+	 * @since 4.4.0 The `$transient` parameter was added.
 	 *
-	 * @param mixed $value Value of site transient.
+	 * @param mixed  $value     New value of site transient.
+	 * @param string $transient Transient name.
 	 */
-	$value = apply_filters( 'pre_set_site_transient_' . $transient, $value );
+	$value = apply_filters( "pre_set_site_transient_{$transient}", $value, $transient );
 
 	$expiration = (int) $expiration;
 
+	/**
+	 * Filters the expiration for a site transient before its value is set.
+	 *
+	 * The dynamic portion of the hook name, `$transient`, refers to the transient name.
+	 *
+	 * @since 4.4.0
+	 *
+	 * @param int    $expiration Time until expiration in seconds. Use 0 for no expiration.
+	 * @param mixed  $value      New value of site transient.
+	 * @param string $transient  Transient name.
+	 */
+	$expiration = apply_filters( "expiration_of_site_transient_{$transient}", $expiration, $value, $transient );
+
 	if ( wp_using_ext_object_cache() ) {
 		$result = wp_cache_set( $transient, $value, 'site-transient', $expiration );
 	} else {
@@ -1441,11 +1787,13 @@
 		 * The dynamic portion of the hook name, `$transient`, refers to the transient name.
 		 *
 		 * @since 3.0.0
+		 * @since 4.4.0 The `$transient` parameter was added
 		 *
-		 * @param mixed $value      Site transient value.
-		 * @param int   $expiration Time until expiration in seconds. Default 0.
+		 * @param mixed  $value      Site transient value.
+		 * @param int    $expiration Time until expiration in seconds.
+		 * @param string $transient  Transient name.
 		 */
-		do_action( 'set_site_transient_' . $transient, $value, $expiration );
+		do_action( "set_site_transient_{$transient}", $value, $expiration, $transient );
 
 		/**
 		 * Fires after the value for a site transient has been set.
@@ -1454,9 +1802,335 @@
 		 *
 		 * @param string $transient  The name of the site transient.
 		 * @param mixed  $value      Site transient value.
-		 * @param int    $expiration Time until expiration in seconds. Default 0.
+		 * @param int    $expiration Time until expiration in seconds.
 		 */
 		do_action( 'setted_site_transient', $transient, $value, $expiration );
 	}
 	return $result;
 }
+
+/**
+ * Register default settings available in WordPress.
+ *
+ * The settings registered here are primarily useful for the REST API, so this
+ * does not encompass all settings available in WordPress.
+ *
+ * @since 4.7.0
+ */
+function register_initial_settings() {
+	register_setting( 'general', 'blogname', array(
+		'show_in_rest' => array(
+			'name' => 'title',
+		),
+		'type'         => 'string',
+		'description'  => __( 'Site title.' ),
+	) );
+
+	register_setting( 'general', 'blogdescription', array(
+		'show_in_rest' => array(
+			'name' => 'description',
+		),
+		'type'         => 'string',
+		'description'  => __( 'Site tagline.' ),
+	) );
+
+	if ( ! is_multisite() ) {
+		register_setting( 'general', 'siteurl', array(
+			'show_in_rest' => array(
+				'name'    => 'url',
+				'schema'  => array(
+					'format' => 'uri',
+				),
+			),
+			'type'         => 'string',
+			'description'  => __( 'Site URL.' ),
+		) );
+	}
+
+	if ( ! is_multisite() ) {
+		register_setting( 'general', 'admin_email', array(
+			'show_in_rest' => array(
+				'name'    => 'email',
+				'schema'  => array(
+					'format' => 'email',
+				),
+			),
+			'type'         => 'string',
+			'description'  => __( 'This address is used for admin purposes, like new user notification.' ),
+		) );
+	}
+
+	register_setting( 'general', 'timezone_string', array(
+		'show_in_rest' => array(
+			'name' => 'timezone',
+		),
+		'type'         => 'string',
+		'description'  => __( 'A city in the same timezone as you.' ),
+	) );
+
+	register_setting( 'general', 'date_format', array(
+		'show_in_rest' => true,
+		'type'         => 'string',
+		'description'  => __( 'A date format for all date strings.' ),
+	) );
+
+	register_setting( 'general', 'time_format', array(
+		'show_in_rest' => true,
+		'type'         => 'string',
+		'description'  => __( 'A time format for all time strings.' ),
+	) );
+
+	register_setting( 'general', 'start_of_week', array(
+		'show_in_rest' => true,
+		'type'         => 'integer',
+		'description'  => __( 'A day number of the week that the week should start on.' ),
+	) );
+
+	register_setting( 'general', 'WPLANG', array(
+		'show_in_rest' => array(
+			'name' => 'language',
+		),
+		'type'         => 'string',
+		'description'  => __( 'WordPress locale code.' ),
+		'default'      => 'en_US',
+	) );
+
+	register_setting( 'writing', 'use_smilies', array(
+		'show_in_rest' => true,
+		'type'         => 'boolean',
+		'description'  => __( 'Convert emoticons like :-) and :-P to graphics on display.' ),
+		'default'      => true,
+	) );
+
+	register_setting( 'writing', 'default_category', array(
+		'show_in_rest' => true,
+		'type'         => 'integer',
+		'description'  => __( 'Default post category.' ),
+	) );
+
+	register_setting( 'writing', 'default_post_format', array(
+		'show_in_rest' => true,
+		'type'         => 'string',
+		'description'  => __( 'Default post format.' ),
+	) );
+
+	register_setting( 'reading', 'posts_per_page', array(
+		'show_in_rest' => true,
+		'type'         => 'integer',
+		'description'  => __( 'Blog pages show at most.' ),
+		'default'      => 10,
+	) );
+
+	register_setting( 'discussion', 'default_ping_status', array(
+		'show_in_rest' => array(
+			'schema'   => array(
+				'enum' => array( 'open', 'closed' ),
+			),
+		),
+		'type'         => 'string',
+		'description'  => __( 'Allow link notifications from other blogs (pingbacks and trackbacks) on new articles.' ),
+	) );
+
+	register_setting( 'discussion', 'default_comment_status', array(
+		'show_in_rest' => array(
+			'schema'   => array(
+				'enum' => array( 'open', 'closed' ),
+			),
+		),
+		'type'         => 'string',
+		'description'  => __( 'Allow people to post comments on new articles.' ),
+	) );
+
+}
+
+/**
+ * Register a setting and its data.
+ *
+ * @since 2.7.0
+ * @since 4.7.0 `$args` can be passed to set flags on the setting, similar to `register_meta()`.
+ *
+ * @global array $new_whitelist_options
+ * @global array $wp_registered_settings
+ *
+ * @param string $option_group A settings group name. Should correspond to a whitelisted option key name.
+ * 	Default whitelisted option key names include "general," "discussion," and "reading," among others.
+ * @param string $option_name The name of an option to sanitize and save.
+ * @param array  $args {
+ *     Data used to describe the setting when registered.
+ *
+ *     @type string   $type              The type of data associated with this setting.
+ *                                       Valid values are 'string', 'boolean', 'integer', and 'number'.
+ *     @type string   $description       A description of the data attached to this setting.
+ *     @type callable $sanitize_callback A callback function that sanitizes the option's value.
+ *     @type bool     $show_in_rest      Whether data associated with this setting should be included in the REST API.
+ *     @type mixed    $default           Default value when calling `get_option()`.
+ * }
+ */
+function register_setting( $option_group, $option_name, $args = array() ) {
+	global $new_whitelist_options, $wp_registered_settings;
+
+	$defaults = array(
+		'type'              => 'string',
+		'group'             => $option_group,
+		'description'       => '',
+		'sanitize_callback' => null,
+		'show_in_rest'      => false,
+	);
+
+	// Back-compat: old sanitize callback is added.
+	if ( is_callable( $args ) ) {
+		$args = array(
+			'sanitize_callback' => $args,
+		);
+	}
+
+	/**
+	 * Filters the registration arguments when registering a setting.
+	 *
+	 * @since 4.7.0
+	 *
+	 * @param array  $args         Array of setting registration arguments.
+	 * @param array  $defaults     Array of default arguments.
+	 * @param string $option_group Setting group.
+	 * @param string $option_name  Setting name.
+	 */
+	$args = apply_filters( 'register_setting_args', $args, $defaults, $option_group, $option_name );
+	$args = wp_parse_args( $args, $defaults );
+
+	if ( ! is_array( $wp_registered_settings ) ) {
+		$wp_registered_settings = array();
+	}
+
+	if ( 'misc' == $option_group ) {
+		_deprecated_argument( __FUNCTION__, '3.0.0',
+			/* translators: %s: misc */
+			sprintf( __( 'The "%s" options group has been removed. Use another settings group.' ),
+				'misc'
+			)
+		);
+		$option_group = 'general';
+	}
+
+	if ( 'privacy' == $option_group ) {
+		_deprecated_argument( __FUNCTION__, '3.5.0',
+			/* translators: %s: privacy */
+			sprintf( __( 'The "%s" options group has been removed. Use another settings group.' ),
+				'privacy'
+			)
+		);
+		$option_group = 'reading';
+	}
+
+	$new_whitelist_options[ $option_group ][] = $option_name;
+	if ( ! empty( $args['sanitize_callback'] ) ) {
+		add_filter( "sanitize_option_{$option_name}", $args['sanitize_callback'] );
+	}
+	if ( array_key_exists( 'default', $args ) ) {
+		add_filter( "default_option_{$option_name}", 'filter_default_option', 10, 3 );
+	}
+
+	$wp_registered_settings[ $option_name ] = $args;
+}
+
+/**
+ * Unregister a setting.
+ *
+ * @since 2.7.0
+ * @since 4.7.0 `$sanitize_callback` was deprecated. The callback from `register_setting()` is now used instead.
+ *
+ * @global array $new_whitelist_options
+ *
+ * @param string   $option_group      The settings group name used during registration.
+ * @param string   $option_name       The name of the option to unregister.
+ * @param callable $deprecated        Deprecated.
+ */
+function unregister_setting( $option_group, $option_name, $deprecated = '' ) {
+	global $new_whitelist_options, $wp_registered_settings;
+
+	if ( 'misc' == $option_group ) {
+		_deprecated_argument( __FUNCTION__, '3.0.0',
+			/* translators: %s: misc */
+			sprintf( __( 'The "%s" options group has been removed. Use another settings group.' ),
+				'misc'
+			)
+		);
+		$option_group = 'general';
+	}
+
+	if ( 'privacy' == $option_group ) {
+		_deprecated_argument( __FUNCTION__, '3.5.0',
+			/* translators: %s: privacy */
+			sprintf( __( 'The "%s" options group has been removed. Use another settings group.' ),
+				'privacy'
+			)
+		);
+		$option_group = 'reading';
+	}
+
+	$pos = array_search( $option_name, (array) $new_whitelist_options[ $option_group ] );
+	if ( $pos !== false ) {
+		unset( $new_whitelist_options[ $option_group ][ $pos ] );
+	}
+	if ( '' !== $deprecated ) {
+		_deprecated_argument( __FUNCTION__, '4.7.0',
+			/* translators: 1: $sanitize_callback, 2: register_setting() */
+			sprintf( __( '%1$s is deprecated. The callback from %2$s is used instead.' ),
+				'<code>$sanitize_callback</code>',
+				'<code>register_setting()</code>'
+			)
+		);
+		remove_filter( "sanitize_option_{$option_name}", $deprecated );
+	}
+
+	if ( isset( $wp_registered_settings[ $option_name ] ) ) {
+		// Remove the sanitize callback if one was set during registration.
+		if ( ! empty( $wp_registered_settings[ $option_name ]['sanitize_callback'] ) ) {
+			remove_filter( "sanitize_option_{$option_name}", $wp_registered_settings[ $option_name ]['sanitize_callback'] );
+		}
+
+		unset( $wp_registered_settings[ $option_name ] );
+	}
+}
+
+/**
+ * Retrieves an array of registered settings.
+ *
+ * @since 4.7.0
+ *
+ * @return array List of registered settings, keyed by option name.
+ */
+function get_registered_settings() {
+	global $wp_registered_settings;
+
+	if ( ! is_array( $wp_registered_settings ) ) {
+		return array();
+	}
+
+	return $wp_registered_settings;
+}
+
+/**
+ * Filter the default value for the option.
+ *
+ * For settings which register a default setting in `register_setting()`, this
+ * function is added as a filter to `default_option_{$option}`.
+ *
+ * @since 4.7.0
+ *
+ * @param mixed $default Existing default value to return.
+ * @param string $option Option name.
+ * @param bool $passed_default Was `get_option()` passed a default value?
+ * @return mixed Filtered default value.
+ */
+function filter_default_option( $default, $option, $passed_default ) {
+	if ( $passed_default ) {
+		return $default;
+	}
+
+	$registered = get_registered_settings();
+	if ( empty( $registered[ $option ] ) ) {
+		return $default;
+	}
+
+	return $registered[ $option ]['default'];
+}