X-Git-Url: https://scripts.mit.edu/gitweb/autoinstalls/wordpress.git/blobdiff_plain/53a5df18dd17a11c18781e78349feb3e139096b4..16e7b37c7914d753890c1a05a9335f3b43751eb8:/wp-includes/option.php

diff --git a/wp-includes/option.php b/wp-includes/option.php
index 6f7a3a60..ac17c2f5 100644
--- a/wp-includes/option.php
+++ b/wp-includes/option.php
@@ -3,10 +3,11 @@
  * Option API
  *
  * @package WordPress
+ * @subpackage Option
  */
 
 /**
- * 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
@@ -15,18 +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_$option'} filter callback.
+ *
  * @since 1.5.0
- * @package WordPress
- * @subpackage Option
- * @uses apply_filters() Calls 'pre_option_$option' before checking the option.
- * 	Any value other than false will "short-circuit" the retrieval of the option
- *	and return the returned value. You should not try to override special options,
- * 	but you will not be prevented from doing so.
- * @uses apply_filters() Calls 'option_$option', after checking the option, with
- * 	the option value.
- *
- * @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 ) {
@@ -36,19 +34,51 @@ function get_option( $option, $default = false ) {
 	if ( empty( $option ) )
 		return false;
 
-	// Allow plugins to short-circuit options.
-	$pre = apply_filters( 'pre_option_' . $option, false );
+	/**
+	 * Filters the value of an existing option before it is retrieved.
+	 *
+	 * The dynamic portion of the hook name, `$option`, refers to the option name.
+	 *
+	 * Passing a truthy value to the filter will short-circuit retrieving
+	 * the option value, returning the passed value instead.
+	 *
+	 * @since 1.5.0
+	 * @since 4.4.0 The `$option` parameter was added.
+	 *
+	 * @param bool|mixed $pre_option Value to return instead of the option value.
+	 *                               Default false to skip it.
+	 * @param string     $option     Option name.
+	 */
+	$pre = apply_filters( "pre_option_{$option}", false, $option );
 	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] ) )
-			return apply_filters( 'default_option_' . $option, $default );
+		if ( isset( $notoptions[ $option ] ) ) {
+			/**
+			 * Filters the default value for an option.
+			 *
+			 * The dynamic portion of the hook name, `$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 string $option  Option name.
+			 * @param bool   $passed_default Was `get_option()` passed a default value?
+			 */
+			return apply_filters( "default_option_{$option}", $default, $option, $passed_default );
+		}
 
 		$alloptions = wp_load_alloptions();
 
@@ -65,9 +95,14 @@ function get_option( $option, $default = false ) {
 					$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' );
-					return apply_filters( 'default_option_' . $option, $default );
+
+					/** This filter is documented in wp-includes/option.php */
+					return apply_filters( 'default_option_' . $option, $default, $option, $passed_default );
 				}
 			}
 		}
@@ -75,10 +110,12 @@ function get_option( $option, $default = false ) {
 		$suppress = $wpdb->suppress_errors();
 		$row = $wpdb->get_row( $wpdb->prepare( "SELECT option_value FROM $wpdb->options WHERE option_name = %s LIMIT 1", $option ) );
 		$wpdb->suppress_errors( $suppress );
-		if ( is_object( $row ) )
+		if ( is_object( $row ) ) {
 			$value = $row->option_value;
-		else
-			return apply_filters( 'default_option_' . $option, $default );
+		} else {
+			/** This filter is documented in wp-includes/option.php */
+			return apply_filters( 'default_option_' . $option, $default, $option, $passed_default );
+		}
 	}
 
 	// If home is not set use siteurl.
@@ -88,7 +125,20 @@ function get_option( $option, $default = false ) {
 	if ( in_array( $option, array('siteurl', 'home', 'category_base', 'tag_base') ) )
 		$value = untrailingslashit( $value );
 
-	return apply_filters( 'option_' . $option, maybe_unserialize( $value ) );
+	/**
+	 * Filters the value of an existing option.
+	 *
+	 * The dynamic portion of the hook name, `$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 string $option Option name.
+	 */
+	return apply_filters( "option_{$option}", maybe_unserialize( $value ), $option );
 }
 
 /**
@@ -98,8 +148,6 @@ function get_option( $option, $default = false ) {
  * and 'notoptions' options.
  *
  * @since 2.2.0
- * @package WordPress
- * @subpackage Option
  *
  * @param string $option Option name.
  */
@@ -111,10 +159,7 @@ function wp_protect_special_option( $option ) {
 /**
  * Print option value after sanitizing for forms.
  *
- * @uses attr Sanitizes value.
  * @since 1.5.0
- * @package WordPress
- * @subpackage Option
  *
  * @param string $option Option name.
  */
@@ -126,15 +171,15 @@ function form_option( $option ) {
  * Loads and caches all autoloaded options, if available or all options.
  *
  * @since 2.2.0
- * @package WordPress
- * @subpackage Option
+ *
+ * @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
 		$alloptions = false;
@@ -148,7 +193,7 @@ function wp_load_alloptions() {
 		foreach ( (array) $alloptions_db as $o ) {
 			$alloptions[$o->option_name] = $o->option_value;
 		}
-		if ( !defined( 'WP_INSTALLING' ) || !is_multisite() )
+		if ( ! wp_installing() || ! is_multisite() )
 			wp_cache_add( 'alloptions', $alloptions, 'options' );
 	}
 
@@ -159,15 +204,15 @@ function wp_load_alloptions() {
  * Loads and caches certain often requested site options if is_multisite() and a persistent cache is not being used.
  *
  * @since 3.0.0
- * @package WordPress
- * @subpackage Option
+ *
+ * @global wpdb $wpdb WordPress database abstraction object.
  *
  * @param int $site_id Optional site ID for which to query the options. Defaults to the current site.
  */
 function wp_load_core_site_options( $site_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) )
@@ -194,24 +239,23 @@ function wp_load_core_site_options( $site_id = null ) {
  * it will be serialized before it is inserted into the database. Remember,
  * resources can not be serialized or added as an option.
  *
- * If the option does not exist, then the option will be added with the option
- * value, but you will not be able to set whether it is autoloaded. If you want
- * to set whether an option is autoloaded, then you need to use the add_option().
+ * If the option does not exist, then the option will be added with the option value,
+ * with an `$autoload` value of 'yes'.
  *
  * @since 1.0.0
- * @package WordPress
- * @subpackage Option
+ * @since 4.2.0 The `$autoload` parameter was added.
  *
- * @uses apply_filters() Calls 'pre_update_option_$option' hook to allow overwriting the
- * 	option value to be stored.
- * @uses do_action() Calls 'update_option' hook before updating the option.
- * @uses do_action() Calls 'update_option_$option' and 'updated_option' hooks on success.
+ * @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      $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'|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 ) {
+function update_option( $option, $value, $autoload = null ) {
 	global $wpdb;
 
 	$option = trim($option);
@@ -225,19 +269,68 @@ function update_option( $option, $value ) {
 
 	$value = sanitize_option( $option, $value );
 	$old_value = get_option( $option );
-	$value = apply_filters( 'pre_update_option_' . $option, $value, $old_value );
+
+	/**
+	 * Filters a specific option before its value is (maybe) serialized and updated.
+	 *
+	 * The dynamic portion of the hook name, `$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 string $option    Option name.
+	 */
+	$value = apply_filters( "pre_update_option_{$option}", $value, $old_value, $option );
+
+	/**
+	 * Filters an option before its value is (maybe) serialized and updated.
+	 *
+	 * @since 3.9.0
+	 *
+	 * @param mixed  $value     The new, unserialized option value.
+	 * @param string $option    Name of the option.
+	 * @param mixed  $old_value The old option value.
+	 */
+	$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 )
 		return false;
 
-	if ( false === $old_value )
-		return add_option( $option, $value );
+	/** This filter is documented in wp-includes/option.php */
+	if ( apply_filters( 'default_option_' . $option, false, $option, false ) === $old_value ) {
+		// Default setting for new options is 'yes'.
+		if ( null === $autoload ) {
+			$autoload = 'yes';
+		}
+
+		return add_option( $option, $value, '', $autoload );
+	}
 
 	$serialized_value = maybe_serialize( $value );
 
+	/**
+	 * Fires immediately before an option value is updated.
+	 *
+	 * @since 2.9.0
+	 *
+	 * @param string $option    Name of the option to update.
+	 * @param mixed  $old_value The old option value.
+	 * @param mixed  $value     The new option value.
+	 */
 	do_action( 'update_option', $option, $old_value, $value );
-	$result = $wpdb->update( $wpdb->options, array( 'option_value' => $serialized_value ), array( 'option_name' => $option ) );
+
+	$update_args = array(
+		'option_value' => $serialized_value,
+	);
+
+	if ( null !== $autoload ) {
+		$update_args['autoload'] = ( 'no' === $autoload || false === $autoload ) ? 'no' : 'yes';
+	}
+
+	$result = $wpdb->update( $wpdb->options, $update_args, array( 'option_name' => $option ) );
 	if ( ! $result )
 		return false;
 
@@ -247,7 +340,7 @@ function update_option( $option, $value ) {
 		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;
@@ -257,7 +350,29 @@ function update_option( $option, $value ) {
 		}
 	}
 
-	do_action( "update_option_{$option}", $old_value, $value );
+	/**
+	 * Fires after the value of a specific option has been successfully updated.
+	 *
+	 * The dynamic portion of the hook name, `$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 string $option    Option name.
+	 */
+	do_action( "update_option_{$option}", $old_value, $value, $option );
+
+	/**
+	 * Fires after the value of an option has been successfully updated.
+	 *
+	 * @since 2.9.0
+	 *
+	 * @param string $option    Name of the updated option.
+	 * @param mixed  $old_value The old option value.
+	 * @param mixed  $value     The new option value.
+	 */
 	do_action( 'updated_option', $option, $old_value, $value );
 	return true;
 }
@@ -274,24 +389,22 @@ function update_option( $option, $value ) {
  * aren't adding a protected WordPress option. Care should be taken to not name
  * options the same as the ones which are protected.
  *
- * @package WordPress
- * @subpackage Option
  * @since 1.0.0
  *
- * @uses do_action() Calls 'add_option' hook before adding the option.
- * @uses do_action() Calls 'add_option_$option' and 'added_option' hooks on success.
+ * @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 mixed $deprecated Optional. Description. Not used anymore.
- * @param bool $autoload Optional. Default is enabled. Whether to load the option when WordPress starts up.
+ * @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.
+ * @param string|bool    $autoload    Optional. Whether to load the option when WordPress starts up.
+ *                                    Default is enabled. Accepts 'no' to disable for legacy reasons.
  * @return bool False if option was not added and true if option was added.
  */
 function add_option( $option, $value = '', $deprecated = '', $autoload = 'yes' ) {
 	global $wpdb;
 
 	if ( !empty( $deprecated ) )
-		_deprecated_argument( __FUNCTION__, '2.3' );
+		_deprecated_argument( __FUNCTION__, '2.3.0' );
 
 	$option = trim($option);
 	if ( empty($option) )
@@ -307,18 +420,28 @@ function add_option( $option, $value = '', $deprecated = '', $autoload = 'yes' )
 	// 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', 'options' );
 	if ( !is_array( $notoptions ) || !isset( $notoptions[$option] ) )
-		if ( false !== get_option( $option ) )
+		/** This filter is documented in wp-includes/option.php */
+		if ( apply_filters( 'default_option_' . $option, false, $option, false ) !== get_option( $option ) )
 			return false;
 
 	$serialized_value = maybe_serialize( $value );
-	$autoload = ( 'no' === $autoload ) ? 'no' : 'yes';
+	$autoload = ( 'no' === $autoload || false === $autoload ) ? 'no' : 'yes';
+
+	/**
+	 * Fires before an option is added.
+	 *
+	 * @since 2.9.0
+	 *
+	 * @param string $option Name of the option to add.
+	 * @param mixed  $value  Value of the option.
+	 */
 	do_action( 'add_option', $option, $value );
 
 	$result = $wpdb->query( $wpdb->prepare( "INSERT INTO `$wpdb->options` (`option_name`, `option_value`, `autoload`) VALUES (%s, %s, %s) ON DUPLICATE KEY UPDATE `option_name` = VALUES(`option_name`), `option_value` = VALUES(`option_value`), `autoload` = VALUES(`autoload`)", $option, $serialized_value, $autoload ) );
 	if ( ! $result )
 		return false;
 
-	if ( ! defined( 'WP_INSTALLING' ) ) {
+	if ( ! wp_installing() ) {
 		if ( 'yes' == $autoload ) {
 			$alloptions = wp_load_alloptions();
 			$alloptions[ $option ] = $serialized_value;
@@ -335,7 +458,27 @@ function add_option( $option, $value = '', $deprecated = '', $autoload = 'yes' )
 		wp_cache_set( 'notoptions', $notoptions, 'options' );
 	}
 
+	/**
+	 * Fires after a specific option has been added.
+	 *
+	 * The dynamic portion of the hook name, `$option`, refers to the option name.
+	 *
+	 * @since 2.5.0 As "add_option_{$name}"
+	 * @since 3.0.0
+	 *
+	 * @param string $option Name of the option to add.
+	 * @param mixed  $value  Value of the option.
+	 */
 	do_action( "add_option_{$option}", $option, $value );
+
+	/**
+	 * Fires after an option has been added.
+	 *
+	 * @since 2.9.0
+	 *
+	 * @param string $option Name of the added option.
+	 * @param mixed  $value  Value of the option.
+	 */
 	do_action( 'added_option', $option, $value );
 	return true;
 }
@@ -343,12 +486,9 @@ function add_option( $option, $value = '', $deprecated = '', $autoload = 'yes' )
 /**
  * Removes option by name. Prevents removal of protected WordPress options.
  *
- * @package WordPress
- * @subpackage Option
  * @since 1.2.0
  *
- * @uses do_action() Calls 'delete_option' hook before option is deleted.
- * @uses do_action() Calls 'deleted_option' and 'delete_option_$option' hooks on success.
+ * @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.
@@ -366,9 +506,18 @@ function delete_option( $option ) {
 	$row = $wpdb->get_row( $wpdb->prepare( "SELECT autoload FROM $wpdb->options WHERE option_name = %s", $option ) );
 	if ( is_null( $row ) )
 		return false;
+
+	/**
+	 * Fires immediately before an option is deleted.
+	 *
+	 * @since 2.9.0
+	 *
+	 * @param string $option Name of the option to delete.
+	 */
 	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] ) ) {
@@ -380,7 +529,25 @@ function delete_option( $option ) {
 		}
 	}
 	if ( $result ) {
-		do_action( "delete_option_$option", $option );
+
+		/**
+		 * Fires after a specific option has been deleted.
+		 *
+		 * The dynamic portion of the hook name, `$option`, refers to the option name.
+		 *
+		 * @since 3.0.0
+		 *
+		 * @param string $option Name of the deleted option.
+		 */
+		do_action( "delete_option_{$option}", $option );
+
+		/**
+		 * Fires after an option has been deleted.
+		 *
+		 * @since 2.9.0
+		 *
+		 * @param string $option Name of the deleted option.
+		 */
 		do_action( 'deleted_option', $option );
 		return true;
 	}
@@ -391,17 +558,22 @@ function delete_option( $option ) {
  * Delete a transient.
  *
  * @since 2.8.0
- * @package WordPress
- * @subpackage Transient
- *
- * @uses do_action() Calls 'delete_transient_$transient' hook before transient is deleted.
- * @uses do_action() Calls 'deleted_transient' hook on success.
  *
  * @param string $transient Transient name. Expected to not be SQL-escaped.
  * @return bool true if successful, false otherwise
  */
 function delete_transient( $transient ) {
-	do_action( 'delete_transient_' . $transient, $transient );
+
+	/**
+	 * Fires immediately before a specific transient is deleted.
+	 *
+	 * The dynamic portion of the hook name, `$transient`, refers to the transient name.
+	 *
+	 * @since 3.0.0
+	 *
+	 * @param string $transient Transient name.
+	 */
+	do_action( "delete_transient_{$transient}", $transient );
 
 	if ( wp_using_ext_object_cache() ) {
 		$result = wp_cache_delete( $transient, 'transient' );
@@ -413,32 +585,51 @@ function delete_transient( $transient ) {
 			delete_option( $option_timeout );
 	}
 
-	if ( $result )
+	if ( $result ) {
+
+		/**
+		 * Fires after a transient is deleted.
+		 *
+		 * @since 3.0.0
+		 *
+		 * @param string $transient Deleted transient name.
+		 */
 		do_action( 'deleted_transient', $transient );
+	}
+
 	return $result;
 }
 
 /**
  * Get the value of a transient.
  *
- * If the transient does not exist or does not have a value, then the return value
- * will be false.
- *
- * @uses apply_filters() Calls 'pre_transient_$transient' hook before checking the transient.
- * 	Any value other than false will "short-circuit" the retrieval of the transient
- *	and return the returned value.
- * @uses apply_filters() Calls 'transient_$option' hook, after checking the transient, with
- * 	the transient value.
+ * If the transient does not exist, does not have a value, or has expired,
+ * then the return value will be false.
  *
  * @since 2.8.0
- * @package WordPress
- * @subpackage Transient
  *
- * @param string $transient Transient name. Expected to not be SQL-escaped
- * @return mixed Value of transient
+ * @param string $transient Transient name. Expected to not be SQL-escaped.
+ * @return mixed Value of transient.
  */
 function get_transient( $transient ) {
-	$pre = apply_filters( 'pre_transient_' . $transient, false );
+
+	/**
+	 * Filters the value of an existing transient.
+	 *
+	 * The dynamic portion of the hook name, `$transient`, refers to the transient name.
+	 *
+	 * Passing a truthy value to the filter will effectively short-circuit retrieval
+	 * 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 string $transient     Transient name.
+	 */
+	$pre = apply_filters( "pre_transient_{$transient}", false, $transient );
 	if ( false !== $pre )
 		return $pre;
 
@@ -446,12 +637,13 @@ function get_transient( $transient ) {
 		$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;
@@ -463,7 +655,18 @@ function get_transient( $transient ) {
 			$value = get_option( $transient_option );
 	}
 
-	return apply_filters( 'transient_' . $transient, $value );
+	/**
+	 * Filters an existing transient's value.
+	 *
+	 * The dynamic portion of the hook name, `$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 string $transient Transient name.
+	 */
+	return apply_filters( "transient_{$transient}", $value, $transient );
 }
 
 /**
@@ -473,42 +676,105 @@ function get_transient( $transient ) {
  * it will be serialized before it is set.
  *
  * @since 2.8.0
- * @package WordPress
- * @subpackage Transient
  *
- * @uses apply_filters() Calls 'pre_set_transient_$transient' hook to allow overwriting the
- * 	transient value to be stored.
- * @uses do_action() Calls 'set_transient_$transient' and 'setted_transient' hooks on success.
- *
- * @param string $transient Transient name. Expected to not be SQL-escaped.
- * @param mixed $value Transient value. Must be serializable if non-scalar. Expected to not be SQL-escaped.
- * @param int $expiration Time until expiration in seconds, default 0
+ * @param string $transient  Transient name. Expected to not be SQL-escaped. Must be
+ *                           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 (no expiration).
  * @return bool False if value was not set and true if value was set.
  */
 function set_transient( $transient, $value, $expiration = 0 ) {
-	$value = apply_filters( 'pre_set_transient_' . $transient, $value );
+
 	$expiration = (int) $expiration;
 
+	/**
+	 * Filters a specific transient before its value is set.
+	 *
+	 * The dynamic portion of the hook name, `$transient`, refers to the transient name.
+	 *
+	 * @since 3.0.0
+	 * @since 4.2.0 The `$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 string $transient  Transient name.
+	 */
+	$value = apply_filters( "pre_set_transient_{$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 )
-				update_option( $transient_timeout, time() + $expiration );
-			$result = update_option( $transient, $value );
+			// 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_option );
+					add_option( $transient_timeout, time() + $expiration, '', 'no' );
+					$result = add_option( $transient_option, $value, '', 'no' );
+					$update = false;
+				} else {
+					update_option( $transient_timeout, time() + $expiration );
+				}
+			}
+			if ( $update ) {
+				$result = update_option( $transient_option, $value );
+			}
 		}
 	}
+
 	if ( $result ) {
-		do_action( 'set_transient_' . $transient, $value, $expiration );
+
+		/**
+		 * Fires after the value for a specific transient has been set.
+		 *
+		 * The dynamic portion of the hook name, `$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.
+		 * @param string $transient  The name of the transient.
+		 */
+		do_action( "set_transient_{$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.
+		 */
 		do_action( 'setted_transient', $transient, $value, $expiration );
 	}
 	return $result;
@@ -521,23 +787,21 @@ function set_transient( $transient, $value, $expiration = 0 ) {
  * cookie exists (different browser used), adds the last saved cookie restoring
  * the settings.
  *
- * @package WordPress
- * @subpackage Option
  * @since 2.7.0
  */
 function wp_user_settings() {
 
-	if ( ! is_admin() )
-		return;
-
-	if ( defined('DOING_AJAX') )
+	if ( ! is_admin() || wp_doing_ajax() ) {
 		return;
+	}
 
-	if ( ! $user_id = get_current_user_id() )
+	if ( ! $user_id = get_current_user_id() ) {
 		return;
+	}
 
-	if ( is_super_admin() && ! is_user_member_of_blog() )
+	if ( is_super_admin() && ! is_user_member_of_blog() ) {
 		return;
+	}
 
 	$settings = (string) get_user_option( 'user-settings', $user_id );
 
@@ -560,19 +824,18 @@ function wp_user_settings() {
 	}
 
 	// The cookie is not set in the current browser or the saved value is newer.
-	setcookie( 'wp-settings-' . $user_id, $settings, time() + YEAR_IN_SECONDS, SITECOOKIEPATH );
-	setcookie( 'wp-settings-time-' . $user_id, time(), time() + YEAR_IN_SECONDS, SITECOOKIEPATH );
+	$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;
 }
 
 /**
  * Retrieve user interface setting value based on setting name.
  *
- * @package WordPress
- * @subpackage Option
  * @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.
  */
@@ -586,20 +849,19 @@ function get_user_setting( $name, $default = false ) {
  * 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().
  *
- * @package WordPress
- * @subpackage Option
  * @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 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() )
+	if ( headers_sent() ) {
 		return false;
+	}
 
 	$all_user_settings = get_all_user_settings();
 	$all_user_settings[$name] = $value;
@@ -611,19 +873,18 @@ function set_user_setting( $name, $value ) {
  * 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().
  *
- * @package WordPress
- * @subpackage Option
  * @since 2.7.0
  *
- * @param mixed $names The name or array of names of the setting to be deleted.
- * @return bool true if deleted successfully/false if not.
+ * @param string $names The name or array of names of the setting to be deleted.
+ * @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() )
+	if ( headers_sent() ) {
 		return false;
+	}
 
 	$all_user_settings = get_all_user_settings();
 	$names = (array) $names;
@@ -636,8 +897,9 @@ function delete_user_setting( $names ) {
 		}
 	}
 
-	if ( $deleted )
+	if ( $deleted ) {
 		return wp_set_all_user_settings( $all_user_settings );
+	}
 
 	return false;
 }
@@ -645,32 +907,37 @@ function delete_user_setting( $names ) {
 /**
  * Retrieve all user interface settings.
  *
- * @package WordPress
- * @subpackage Option
  * @since 2.7.0
  *
+ * @global array $_updated_user_settings
+ *
  * @return array the last saved user settings or empty array.
  */
 function get_all_user_settings() {
 	global $_updated_user_settings;
 
-	if ( ! $user_id = get_current_user_id() )
+	if ( ! $user_id = get_current_user_id() ) {
 		return array();
+	}
 
-	if ( isset( $_updated_user_settings ) && is_array( $_updated_user_settings ) )
+	if ( isset( $_updated_user_settings ) && is_array( $_updated_user_settings ) ) {
 		return $_updated_user_settings;
+	}
 
 	$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 ( $cookie && strpos( $cookie, '=' ) ) // '=' cannot be 1st char
+		if ( strpos( $cookie, '=' ) ) { // '=' cannot be 1st char
 			parse_str( $cookie, $user_settings );
-
+		}
 	} else {
 		$option = get_user_option( 'user-settings', $user_id );
-		if ( $option && is_string($option) )
+
+		if ( $option && is_string( $option ) ) {
 			parse_str( $option, $user_settings );
+		}
 	}
 
 	$_updated_user_settings = $user_settings;
@@ -680,32 +947,37 @@ function get_all_user_settings() {
 /**
  * Private. Set all user interface settings.
  *
- * @package WordPress
- * @subpackage Option
  * @since 2.8.0
+ * @access private
+ *
+ * @global array $_updated_user_settings
  *
- * @param array $user_settings
- * @return bool
+ * @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;
 
-	if ( ! $user_id = get_current_user_id() )
+	if ( ! $user_id = get_current_user_id() ) {
 		return false;
+	}
 
-	if ( is_super_admin() && ! is_user_member_of_blog() )
+	if ( is_super_admin() && ! 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 ) )
+		if ( ! empty( $_name ) ) {
 			$settings .= $_name . '=' . $_value . '&';
+		}
 	}
 
-	$settings = rtrim($settings, '&');
+	$settings = rtrim( $settings, '&' );
 	parse_str( $settings, $_updated_user_settings );
 
 	update_user_option( $user_id, 'user-settings', $settings, false );
@@ -717,60 +989,168 @@ function wp_set_all_user_settings( $user_settings ) {
 /**
  * Delete the user settings of the current user.
  *
- * @package WordPress
- * @subpackage Option
  * @since 2.7.0
  */
 function delete_all_user_settings() {
-	if ( ! $user_id = get_current_user_id() )
+	if ( ! $user_id = get_current_user_id() ) {
 		return;
+	}
 
 	update_user_option( $user_id, 'user-settings', '', false );
-	setcookie('wp-settings-' . $user_id, ' ', time() - YEAR_IN_SECONDS, SITECOOKIEPATH);
+	setcookie( 'wp-settings-' . $user_id, ' ', time() - YEAR_IN_SECONDS, SITECOOKIEPATH );
 }
 
 /**
- * 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, $value );
+}
+
+/**
+ * Removes a option by name for the current network.
  *
- * @see get_option()
- * @package WordPress
- * @subpackage Option
  * @since 2.8.0
+ * @since 4.4.0 Modified into wrapper for delete_network_option()
+ *
+ * @see delete_network_option()
  *
- * @uses apply_filters() Calls 'pre_site_option_$option' before checking the option.
- * 	Any value other than false will "short-circuit" the retrieval of the option
- *	and return the returned value.
- * @uses apply_filters() Calls 'site_option_$option', after checking the  option, with
- * 	the option value.
+ * @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.
  *
- * @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.
+ * @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()
+ *
+ * @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;
 
-	// Allow plugins to short-circuit site options.
- 	$pre = apply_filters( 'pre_site_option_' . $option, false );
- 	if ( false !== $pre )
- 		return $pre;
+	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 ) {
+		$network_id = get_current_network_id();
+	}
+
+	/**
+	 * Filters an existing network option before it is retrieved.
+	 *
+	 * The dynamic portion of the hook name, `$option`, refers to the option name.
+	 *
+	 * Passing a truthy value to the filter will effectively short-circuit retrieval,
+	 * returning the passed value instead.
+	 *
+	 * @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.
+	 *
+	 * @param mixed  $pre_option The default value to return if the option does not exist.
+	 * @param string $option     Option name.
+	 * @param int    $network_id ID of the network.
+	 */
+	$pre = apply_filters( "pre_site_option_{$option}", false, $option, $network_id );
+
+	if ( false !== $pre ) {
+		return $pre;
+	}
 
 	// prevent non-existent options from triggering multiple queries
-	$notoptions = wp_cache_get( 'notoptions', 'site-options' );
-	if ( isset( $notoptions[$option] ) )
-		return apply_filters( 'default_site_option_' . $option, $default );
+	$notoptions_key = "$network_id:notoptions";
+	$notoptions = wp_cache_get( $notoptions_key, 'site-options' );
+
+	if ( isset( $notoptions[ $option ] ) ) {
+
+		/**
+		 * Filters a specific default network option.
+		 *
+		 * The dynamic portion of the hook name, `$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 string $option     Option name.
+		 * @param int    $network_id ID of the network.
+		 */
+		return apply_filters( "default_site_option_{$option}", $default, $option, $network_id );
+	}
 
 	if ( ! is_multisite() ) {
-		$default = apply_filters( 'default_site_option_' . $option, $default );
-		$value = get_option($option, $default);
+		/** This filter is documented in wp-includes/option.php */
+		$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 ) ) {
@@ -778,175 +1158,351 @@ function get_site_option( $option, $default = false, $use_cache = true ) {
 				$value = maybe_unserialize( $value );
 				wp_cache_set( $cache_key, $value, 'site-options' );
 			} else {
-				$notoptions[$option] = true;
-				wp_cache_set( 'notoptions', $notoptions, 'site-options' );
-				$value = apply_filters( 'default_site_option_' . $option, $default );
+				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, $option, $network_id );
 			}
 		}
 	}
 
- 	return apply_filters( 'site_option_' . $option, $value );
+	/**
+	 * Filters the value of an existing network option.
+	 *
+	 * The dynamic portion of the hook name, `$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 network option.
+	 * @param string $option     Option name.
+	 * @param int    $network_id ID of the network.
+	 */
+	return apply_filters( "site_option_{$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 4.4.0
  *
  * @see add_option()
- * @package WordPress
- * @subpackage Option
- * @since 2.8.0
  *
- * @uses apply_filters() Calls 'pre_add_site_option_$option' hook to allow overwriting the
- * 	option value to be stored.
- * @uses do_action() Calls 'add_site_option_$option' and 'add_site_option' hooks on success.
+ * @global wpdb $wpdb
  *
- * @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.
+ * @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 );
 
-	$value = apply_filters( 'pre_add_site_option_' . $option, $value );
+	/**
+	 * Filters the value of a specific network option before it is added.
+	 *
+	 * The dynamic portion of the hook name, `$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 network option.
+	 * @param string $option     Option name.
+	 * @param int    $network_id ID of the network.
+	 */
+	$value = apply_filters( "pre_add_site_option_{$option}", $value, $option, $network_id );
+
+	$notoptions_key = "$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', 'site-options' );
-		if ( ! is_array( $notoptions ) || ! isset( $notoptions[$option] ) )
-			if ( false !== get_site_option( $option ) )
+		$notoptions = wp_cache_get( $notoptions_key, 'site-options' );
+		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', 'site-options' ); // yes, again... we need it to be fresh
-		if ( is_array( $notoptions ) && isset( $notoptions[$option] ) ) {
-			unset( $notoptions[$option] );
-			wp_cache_set( 'notoptions', $notoptions, 'site-options' );
+		$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 ] );
+			wp_cache_set( $notoptions_key, $notoptions, 'site-options' );
 		}
 	}
 
 	if ( $result ) {
-		do_action( "add_site_option_{$option}", $option, $value );
-		do_action( "add_site_option", $option, $value );
+
+		/**
+		 * Fires after a specific network option has been successfully added.
+		 *
+		 * The dynamic portion of the hook name, `$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 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, $network_id );
+
+		/**
+		 * Fires after a network option has been successfully added.
+		 *
+		 * @since 3.0.0
+		 * @since 4.7.0 The `$network_id` parameter was added.
+		 *
+		 * @param string $option     Name of 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, $network_id );
+
 		return true;
 	}
+
 	return false;
 }
 
 /**
- * Removes site option by name.
+ * Removes a network option by name.
+ *
+ * @since 4.4.0
  *
  * @see delete_option()
- * @package WordPress
- * @subpackage Option
- * @since 2.8.0
  *
- * @uses do_action() Calls 'pre_delete_site_option_$option' hook before option is deleted.
- * @uses do_action() Calls 'delete_site_option' and 'delete_site_option_$option'
- * 	hooks on success.
+ * @global wpdb $wpdb
  *
- * @param string $option Name of option to remove. Expected to not be SQL-escaped.
+ * @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;
+	}
 
-	do_action( 'pre_delete_site_option_' . $option );
+	$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();
+	}
 
-	if ( !is_multisite() ) {
+	/**
+	 * 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}", $option, $network_id );
+
+	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 ( $result ) {
-		do_action( "delete_site_option_{$option}", $option );
-		do_action( "delete_site_option", $option );
+
+		/**
+		 * Fires after a specific network option has been deleted.
+		 *
+		 * The dynamic portion of the hook name, `$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 network option.
+		 * @param int    $network_id ID of the network.
+		 */
+		do_action( "delete_site_option_{$option}", $option, $network_id );
+
+		/**
+		 * Fires after a network option has been deleted.
+		 *
+		 * @since 3.0.0
+		 * @since 4.7.0 The `$network_id` parameter was added.
+		 *
+		 * @param string $option     Name of the network option.
+		 * @param int    $network_id ID of the network.
+		 */
+		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 4.4.0
  *
  * @see update_option()
- * @since 2.8.0
- * @package WordPress
- * @subpackage Option
  *
- * @uses apply_filters() Calls 'pre_update_site_option_$option' hook to allow overwriting the
- * 	option value to be stored.
- * @uses do_action() Calls 'update_site_option_$option' and 'update_site_option' hooks on success.
+ * @global wpdb $wpdb
  *
- * @param string $option Name of option. Expected to not be SQL-escaped.
- * @param mixed $value Option value. Expected to not be SQL-escaped.
+ * @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;
 
-	wp_protect_special_option( $option );
+	if ( $network_id && ! is_numeric( $network_id ) ) {
+		return false;
+	}
 
-	$old_value = get_site_option( $option );
-	$value = apply_filters( 'pre_update_site_option_' . $option, $value, $old_value );
+	$network_id = (int) $network_id;
 
-	if ( $value === $old_value )
+	// 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_network_option( $network_id, $option, false );
+
+	/**
+	 * Filters a specific network option before its value is updated.
+	 *
+	 * The dynamic portion of the hook name, `$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 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, $option, $network_id );
+
+	if ( $value === $old_value ) {
 		return false;
+	}
 
-	if ( false === $old_value )
-		return add_site_option( $option, $value );
+	if ( false === $old_value ) {
+		return add_network_option( $network_id, $option, $value );
+	}
 
-	$notoptions = wp_cache_get( 'notoptions', 'site-options' );
-	if ( is_array( $notoptions ) && isset( $notoptions[$option] ) ) {
-		unset( $notoptions[$option] );
-		wp_cache_set( 'notoptions', $notoptions, 'site-options' );
+	$notoptions_key = "$network_id:notoptions";
+	$notoptions = wp_cache_get( $notoptions_key, 'site-options' );
+	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' );
 		}
 	}
 
 	if ( $result ) {
-		do_action( "update_site_option_{$option}", $option, $value, $old_value );
-		do_action( "update_site_option", $option, $value, $old_value );
+
+		/**
+		 * Fires after the value of a specific network option has been successfully updated.
+		 *
+		 * The dynamic portion of the hook name, `$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 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, $network_id );
+
+		/**
+		 * Fires after the value of a network option has been successfully updated.
+		 *
+		 * @since 3.0.0
+		 * @since 4.7.0 The `$network_id` parameter was added.
+		 *
+		 * @param string $option     Name of 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, $network_id );
+
 		return true;
 	}
+
 	return false;
 }
 
@@ -954,17 +1510,23 @@ function update_site_option( $option, $value ) {
  * Delete a site transient.
  *
  * @since 2.9.0
- * @package WordPress
- * @subpackage Transient
- *
- * @uses do_action() Calls 'delete_site_transient_$transient' hook before transient is deleted.
- * @uses do_action() Calls 'deleted_site_transient' hook on success.
  *
  * @param string $transient Transient name. Expected to not be SQL-escaped.
  * @return bool True if successful, false otherwise
  */
 function delete_site_transient( $transient ) {
-	do_action( 'delete_site_transient_' . $transient, $transient );
+
+	/**
+	 * Fires immediately before a specific site transient is deleted.
+	 *
+	 * The dynamic portion of the hook name, `$transient`, refers to the transient name.
+	 *
+	 * @since 3.0.0
+	 *
+	 * @param string $transient Transient name.
+	 */
+	do_action( "delete_site_transient_{$transient}", $transient );
+
 	if ( wp_using_ext_object_cache() ) {
 		$result = wp_cache_delete( $transient, 'site-transient' );
 	} else {
@@ -974,33 +1536,54 @@ function delete_site_transient( $transient ) {
 		if ( $result )
 			delete_site_option( $option_timeout );
 	}
-	if ( $result )
+	if ( $result ) {
+
+		/**
+		 * Fires after a transient is deleted.
+		 *
+		 * @since 3.0.0
+		 *
+		 * @param string $transient Deleted transient name.
+		 */
 		do_action( 'deleted_site_transient', $transient );
+	}
+
 	return $result;
 }
 
 /**
  * Get the value of a site transient.
  *
- * If the transient does not exist or does not have a value, then the return value
- * will be false.
+ * If the transient does not exist, does not have a value, or has expired,
+ * then the return value will be false.
  *
- * @see get_transient()
  * @since 2.9.0
- * @package WordPress
- * @subpackage Transient
  *
- * @uses apply_filters() Calls 'pre_site_transient_$transient' hook before checking the transient.
- * 	Any value other than false will "short-circuit" the retrieval of the transient
- *	and return the returned value.
- * @uses apply_filters() Calls 'site_transient_$option' hook, after checking the transient, with
- * 	the transient value.
+ * @see get_transient()
  *
  * @param string $transient Transient name. Expected to not be SQL-escaped.
- * @return mixed Value of transient
+ * @return mixed Value of transient.
  */
 function get_site_transient( $transient ) {
-	$pre = apply_filters( 'pre_site_transient_' . $transient, false );
+
+	/**
+	 * Filters the value of an existing site transient.
+	 *
+	 * The dynamic portion of the hook name, `$transient`, refers to the transient name.
+	 *
+	 * Passing a truthy value to the filter will effectively short-circuit retrieval,
+	 * 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 string $transient          Transient name.
+	 */
+	$pre = apply_filters( "pre_site_transient_{$transient}", false, $transient );
+
 	if ( false !== $pre )
 		return $pre;
 
@@ -1024,7 +1607,18 @@ function get_site_transient( $transient ) {
 			$value = get_site_option( $transient_option );
 	}
 
-	return apply_filters( 'site_transient_' . $transient, $value );
+	/**
+	 * Filters the value of an existing site transient.
+	 *
+	 * The dynamic portion of the hook name, `$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 string $transient Transient name.
+	 */
+	return apply_filters( "site_transient_{$transient}", $value, $transient );
 }
 
 /**
@@ -1033,24 +1627,46 @@ function get_site_transient( $transient ) {
  * You do not need to serialize values, if the value needs to be serialize, then
  * it will be serialized before it is set.
  *
- * @see set_transient()
  * @since 2.9.0
- * @package WordPress
- * @subpackage Transient
  *
- * @uses apply_filters() Calls 'pre_set_site_transient_$transient' hook to allow overwriting the
- * 	transient value to be stored.
- * @uses do_action() Calls 'set_site_transient_$transient' and 'setted_site_transient' hooks on success.
+ * @see set_transient()
  *
- * @param string $transient Transient name. Expected to not be SQL-escaped.
- * @param mixed $value Transient value. Expected to not be SQL-escaped.
- * @param int $expiration Time until expiration in seconds, default 0
+ * @param string $transient  Transient name. Expected to not be SQL-escaped. Must be
+ *                           40 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 (no expiration).
  * @return bool False if value was not set and true if value was set.
  */
 function set_site_transient( $transient, $value, $expiration = 0 ) {
-	$value = apply_filters( 'pre_set_site_transient_' . $transient, $value );
+
+	/**
+	 * Filters the value of a specific site transient before it is set.
+	 *
+	 * The dynamic portion of the hook name, `$transient`, refers to the transient name.
+	 *
+	 * @since 3.0.0
+	 * @since 4.4.0 The `$transient` parameter was added.
+	 *
+	 * @param mixed  $value     New value of site transient.
+	 * @param string $transient Transient name.
+	 */
+	$value = apply_filters( "pre_set_site_transient_{$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 {
@@ -1067,8 +1683,330 @@ function set_site_transient( $transient, $value, $expiration = 0 ) {
 		}
 	}
 	if ( $result ) {
-		do_action( 'set_site_transient_' . $transient, $value, $expiration );
+
+		/**
+		 * Fires after the value for a specific site transient has been set.
+		 *
+		 * The dynamic portion of the hook name, `$transient`, refers to the transient name.
+		 *
+		 * @since 3.0.0
+		 * @since 4.4.0 The `$transient` parameter was added
+		 *
+		 * @param mixed  $value      Site transient value.
+		 * @param int    $expiration Time until expiration in seconds.
+		 * @param string $transient  Transient name.
+		 */
+		do_action( "set_site_transient_{$transient}", $value, $expiration, $transient );
+
+		/**
+		 * Fires after the value for a site transient has been set.
+		 *
+		 * @since 3.0.0
+		 *
+		 * @param string $transient  The name of the site transient.
+		 * @param mixed  $value      Site transient value.
+		 * @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.
+ *     @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', 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', 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', 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', 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 ( '' !== $deprecated ) {
+		_deprecated_argument( __FUNCTION__, '4.7.0', __( '$sanitize_callback is deprecated. The callback from register_setting() is used instead.' ) );
+		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'];
+}