Ticket #59588: option.php

<?php
/**
 * Option API
 *
 * @package WordPress
 * @subpackage Option
 */

/**
 * Retrieves an option value based on an option name.
 *
 * If the option does not exist, and a default value is not provided,
 * boolean false is returned. This could be used to check whether you need
 * to initialize an option during installation of a plugin, however that
 * can be done better by using add_option() which will not overwrite
 * existing options.
 *
 * Not initializing an option and using boolean `false` as a return value
 * is a bad practice as it triggers an additional database query.
 *
 * The type of the returned value can be different from the type that was passed
 * when saving or updating the option. If the option value was serialized,
 * then it will be unserialized when it is returned. In this case the type will
 * be the same. For example, storing a non-scalar value like an array will
 * return the same array.
 *
 * In most cases non-string scalar and null values will be converted and returned
 * as string equivalents.
 *
 * Exceptions:
 *
 * 1. When the option has not been saved in the database, the `$default_value` value
 *    is returned if provided. If not, boolean `false` is returned.
 * 2. When one of the Options API filters is used: {@see 'pre_option_$option'},
 *    {@see 'default_option_$option'}, or {@see 'option_$option'}, the returned
 *    value may not match the expected type.
 * 3. When the option has just been saved in the database, and get_option()
 *    is used right after, non-string scalar and null values are not converted to
 *    string equivalents and the original type is returned.
 *
 * Examples:
 *
 * When adding options like this: `add_option( 'my_option_name', 'value' )`
 * and then retrieving them with `get_option( 'my_option_name' )`, the returned
 * values will be:
 *
 *   - `false` returns `string(0) ""`
 *   - `true`  returns `string(1) "1"`
 *   - `0`     returns `string(1) "0"`
 *   - `1`     returns `string(1) "1"`
 *   - `'0'`   returns `string(1) "0"`
 *   - `'1'`   returns `string(1) "1"`
 *   - `null`  returns `string(0) ""`
 *
 * When adding options with non-scalar values like
 * `add_option( 'my_array', array( false, 'str', null ) )`, the returned value
 * will be identical to the original as it is serialized before saving
 * it in the database:
 *
 *     array(3) {
 *         [0] => bool(false)
 *         [1] => string(3) "str"
 *         [2] => NULL
 *     }
 *
 * @since 1.5.0
 *
 * @global wpdb $wpdb WordPress database abstraction object.
 *
 * @param string $option        Name of the option to retrieve. Expected to not be SQL-escaped.
 * @param mixed  $default_value Optional. Default value to return if the option does not exist.
 * @return mixed Value of the option. A value of any type may be returned, including
 *               scalar (string, boolean, float, integer), null, array, object.
 *               Scalar and null values will be returned as strings as long as they originate
 *               from a database stored option value. If there is no option in the database,
 *               boolean `false` is returned.
 */
function get_option( $option, $default_value = false ) {
        global $wpdb;

        if ( is_scalar( $option ) ) {
                $option = trim( $option );
        }

        if ( empty( $option ) ) {
                return false;
        }

        /*
         * Until a proper _deprecated_option() function can be introduced,
         * redirect requests to deprecated keys to the new, correct ones.
         */
        $deprecated_keys = array(
                'blacklist_keys'    => 'disallowed_keys',
                'comment_whitelist' => 'comment_previously_approved',
        );

        if ( isset( $deprecated_keys[ $option ] ) && ! wp_installing() ) {
                _deprecated_argument(
                        __FUNCTION__,
                        '5.5.0',
                        sprintf(
                                /* translators: 1: Deprecated option key, 2: New option key. */
                                __( 'The "%1$s" option key has been renamed to "%2$s".' ),
                                $option,
                                $deprecated_keys[ $option ]
                        )
                );

                return get_option( $deprecated_keys[ $option ], $default_value );
        }

        /**
         * Filters the value of an existing option before it is retrieved.
         *
         * The dynamic portion of the hook name, `$option`, refers to the option name.
         *
         * Returning a value other than false from the filter will short-circuit retrieval
         * and return that value instead.
         *
         * @since 1.5.0
         * @since 4.4.0 The `$option` parameter was added.
         * @since 4.9.0 The `$default_value` parameter was added.
         *
         * @param mixed  $pre_option    The value to return instead of the option value. This differs from
         *                              `$default_value`, 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_value The fallback value to return if the option does not exist.
         *                              Default false.
         */
        $pre = apply_filters( "pre_option_{$option}", false, $option, $default_value );

        /**
         * Filters the value of all existing options before it is retrieved.
         *
         * Returning a truthy value from the filter will effectively short-circuit retrieval
         * and return the passed value instead.
         *
         * @since 6.1.0
         *
         * @param mixed  $pre_option    The value to return instead of the option value. This differs from
         *                              `$default_value`, 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        Name of the option.
         * @param mixed  $default_value The fallback value to return if the option does not exist.
         *                              Default false.
         */
        $pre = apply_filters( 'pre_option', $pre, $option, $default_value );

        if ( false !== $pre ) {
                return $pre;
        }

        if ( defined( 'WP_SETUP_CONFIG' ) ) {
                return false;
        }

        // 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' );

                // Prevent non-existent `notoptions` key from triggering multiple key lookups.
                if ( ! is_array( $notoptions ) ) {
                        $notoptions = array();
                        wp_cache_set( 'notoptions', $notoptions, 'options' );
                }

                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_value  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_value, $option, $passed_default );
                }

                $alloptions = wp_load_alloptions();

                if ( isset( $alloptions[ $option ] ) ) {
                        $value = $alloptions[ $option ];
                } else {
                        $value = wp_cache_get( $option, 'options' );

                        if ( false === $value ) {
                                $row = $wpdb->get_row( $wpdb->prepare( "SELECT option_value FROM $wpdb->options WHERE option_name = %s LIMIT 1", $option ) );

                                // Has to be get_row() instead of get_var() because of funkiness with 0, false, null values.
                                if ( is_object( $row ) ) {
                                        $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_value, $option, $passed_default );
                                }
                        }
                }
        } else {
                $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 ) ) {
                        $value = $row->option_value;
                } else {
                        /** This filter is documented in wp-includes/option.php */
                        return apply_filters( "default_option_{$option}", $default_value, $option, $passed_default );
                }
        }

        // If home is not set, use siteurl.
        if ( 'home' === $option && '' === $value ) {
                return get_option( 'siteurl' );
        }

        if ( in_array( $option, array( 'siteurl', 'home', 'category_base', 'tag_base' ), true ) ) {
                $value = untrailingslashit( $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.
         */
    $data = maybe_unserialize($value);

    if (!$data && $default_value !== false && gettype($data) !== gettype($default_value))
        $data = $default_value;

    return apply_filters( "option_{$option}", $data, $option );
}

/**
 * Protects WordPress special option from being modified.
 *
 * Will die if $option is in protected list. Protected options are 'alloptions'
 * and 'notoptions' options.
 *
 * @since 2.2.0
 *
 * @param string $option Option name.
 */
function wp_protect_special_option( $option ) {
        if ( 'alloptions' === $option || 'notoptions' === $option ) {
                wp_die(
                        sprintf(
                                /* translators: %s: Option name. */
                                __( '%s is a protected WP option and may not be modified' ),
                                esc_html( $option )
                        )
                );
        }
}

/**
 * Prints option value after sanitizing for forms.
 *
 * @since 1.5.0
 *
 * @param string $option Option name.
 */
function form_option( $option ) {
        echo esc_attr( get_option( $option ) );
}

/**
 * Loads and caches all autoloaded options, if available or all options.
 *
 * @since 2.2.0
 * @since 5.3.1 The `$force_cache` parameter was added.
 *
 * @global wpdb $wpdb WordPress database abstraction object.
 *
 * @param bool $force_cache Optional. Whether to force an update of the local cache
 *                          from the persistent cache. Default false.
 * @return array List of all options.
 */
function wp_load_alloptions( $force_cache = false ) {
        global $wpdb;

        /**
         * Filters the array of alloptions before it is populated.
         *
         * Returning an array from the filter will effectively short circuit
         * wp_load_alloptions(), returning that value instead.
         *
         * @since 6.2.0
         *
         * @param array|null $alloptions  An array of alloptions. Default null.
         * @param bool       $force_cache Whether to force an update of the local cache from the persistent cache. Default false.
         */
        $alloptions = apply_filters( 'pre_wp_load_alloptions', null, $force_cache );
        if ( is_array( $alloptions ) ) {
                return $alloptions;
        }

        if ( ! wp_installing() || ! is_multisite() ) {
                $alloptions = wp_cache_get( 'alloptions', 'options', $force_cache );
        } else {
                $alloptions = false;
        }

        if ( ! $alloptions ) {
                $suppress      = $wpdb->suppress_errors();
                $alloptions_db = $wpdb->get_results( "SELECT option_name, option_value FROM $wpdb->options WHERE autoload = 'yes'" );
                if ( ! $alloptions_db ) {
                        $alloptions_db = $wpdb->get_results( "SELECT option_name, option_value FROM $wpdb->options" );
                }
                $wpdb->suppress_errors( $suppress );

                $alloptions = array();
                foreach ( (array) $alloptions_db as $o ) {
                        $alloptions[ $o->option_name ] = $o->option_value;
                }

                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' );
                }
        }

        /**
         * Filters all options after retrieving them.
         *
         * @since 4.9.0
         *
         * @param array $alloptions Array with all options.
         */
        return apply_filters( 'alloptions', $alloptions );
}

/**
 * Loads and primes caches of certain often requested network options if is_multisite().
 *
 * @since 3.0.0
 * @since 6.3.0 Also prime caches for network options when persistent object cache is enabled.
 *
 * @global wpdb $wpdb WordPress database abstraction object.
 *
 * @param int $network_id Optional. Network ID of network for which to prime network options cache. Defaults to current network.
 */
function wp_load_core_site_options( $network_id = null ) {
        global $wpdb;

        if ( ! is_multisite() || wp_installing() ) {
                return;
        }

        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' );

        if ( wp_using_ext_object_cache() ) {
                $cache_keys = array();
                foreach ( $core_options as $option ) {
                        $cache_keys[] = "{$network_id}:{$option}";
                }
                wp_cache_get_multiple( $cache_keys, 'site-options' );

                return;
        }

        $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", $network_id ) );

        $data = array();
        foreach ( $options as $option ) {
                $key                = $option->meta_key;
                $cache_key          = "{$network_id}:$key";
                $option->meta_value = maybe_unserialize( $option->meta_value );

                $data[ $cache_key ] = $option->meta_value;
        }
        wp_cache_set_multiple( $data, 'site-options' );
}

/**
 * Updates the value of an option that was already added.
 *
 * You do not need to serialize values. If the value needs to be serialized,
 * then it will be serialized before it is inserted into the database.
 * Remember, resources cannot be serialized or added as an option.
 *
 * If the option does not exist, it will be created.

 * This function is designed to work with or without a logged-in user. In terms of security,
 * plugin developers should check the current user's capabilities before updating any options.
 *
 * @since 1.0.0
 * @since 4.2.0 The `$autoload` parameter was added.
 *
 * @global wpdb $wpdb WordPress database abstraction object.
 *
 * @param string      $option   Name of the option to update. 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 True if the value was updated, false otherwise.
 */
function update_option( $option, $value, $autoload = null ) {
        global $wpdb;

        if ( is_scalar( $option ) ) {
                $option = trim( $option );
        }

        if ( empty( $option ) ) {
                return false;
        }

        /*
         * Until a proper _deprecated_option() function can be introduced,
         * redirect requests to deprecated keys to the new, correct ones.
         */
        $deprecated_keys = array(
                'blacklist_keys'    => 'disallowed_keys',
                'comment_whitelist' => 'comment_previously_approved',
        );

        if ( isset( $deprecated_keys[ $option ] ) && ! wp_installing() ) {
                _deprecated_argument(
                        __FUNCTION__,
                        '5.5.0',
                        sprintf(
                                /* translators: 1: Deprecated option key, 2: New option key. */
                                __( 'The "%1$s" option key has been renamed to "%2$s".' ),
                                $option,
                                $deprecated_keys[ $option ]
                        )
                );
                return update_option( $deprecated_keys[ $option ], $value, $autoload );
        }

        wp_protect_special_option( $option );

        if ( is_object( $value ) ) {
                $value = clone $value;
        }

        $value     = sanitize_option( $option, $value );
        $old_value = get_option( $option );

        /**
         * 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.
         *
         * 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, $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 );

        $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;
        }

        $notoptions = wp_cache_get( 'notoptions', 'options' );

        if ( is_array( $notoptions ) && isset( $notoptions[ $option ] ) ) {
                unset( $notoptions[ $option ] );
                wp_cache_set( 'notoptions', $notoptions, 'options' );
        }

        if ( ! wp_installing() ) {
                $alloptions = wp_load_alloptions( true );
                if ( isset( $alloptions[ $option ] ) ) {
                        $alloptions[ $option ] = $serialized_value;
                        wp_cache_set( 'alloptions', $alloptions, 'options' );
                } else {
                        wp_cache_set( $option, $serialized_value, 'options' );
                }
        }

        /**
         * 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;
}

/**
 * Adds a new option.
 *
 * You do not need to serialize values. If the value needs to be serialized,
 * then it will be serialized before it is inserted into the database.
 * Remember, resources cannot be serialized or added as an option.
 *
 * You can create options without values and then update the values later.
 * Existing options will not be updated and checks are performed to ensure that you
 * aren't adding a protected WordPress option. Care should be taken to not name
 * options the same as the ones which are protected.
 *
 * @since 1.0.0
 *
 * @global wpdb $wpdb WordPress database abstraction object.
 *
 * @param string      $option     Name of the 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 True if the option was added, false otherwise.
 */
function add_option( $option, $value = '', $deprecated = '', $autoload = 'yes' ) {
        global $wpdb;

        if ( ! empty( $deprecated ) ) {
                _deprecated_argument( __FUNCTION__, '2.3.0' );
        }

        if ( is_scalar( $option ) ) {
                $option = trim( $option );
        }

        if ( empty( $option ) ) {
                return false;
        }

        /*
         * Until a proper _deprecated_option() function can be introduced,
         * redirect requests to deprecated keys to the new, correct ones.
         */
        $deprecated_keys = array(
                'blacklist_keys'    => 'disallowed_keys',
                'comment_whitelist' => 'comment_previously_approved',
        );

        if ( isset( $deprecated_keys[ $option ] ) && ! wp_installing() ) {
                _deprecated_argument(
                        __FUNCTION__,
                        '5.5.0',
                        sprintf(
                                /* translators: 1: Deprecated option key, 2: New option key. */
                                __( 'The "%1$s" option key has been renamed to "%2$s".' ),
                                $option,
                                $deprecated_keys[ $option ]
                        )
                );
                return add_option( $deprecated_keys[ $option ], $value, $deprecated, $autoload );
        }

        wp_protect_special_option( $option );

        if ( is_object( $value ) ) {
                $value = clone $value;
        }

        $value = sanitize_option( $option, $value );

        /*
         * 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[ $option ] ) ) {
                /** This filter is documented in wp-includes/option.php */
                if ( apply_filters( "default_option_{$option}", false, $option, false ) !== get_option( $option ) ) {
                        return false;
                }
        }

        $serialized_value = maybe_serialize( $value );
        $autoload         = ( 'no' === $autoload || 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 ( ! wp_installing() ) {
                if ( 'yes' === $autoload ) {
                        $alloptions            = wp_load_alloptions( true );
                        $alloptions[ $option ] = $serialized_value;
                        wp_cache_set( 'alloptions', $alloptions, 'options' );
                } else {
                        wp_cache_set( $option, $serialized_value, 'options' );
                }
        }

        // This option exists now.
        $notoptions = wp_cache_get( 'notoptions', 'options' ); // Yes, again... we need it to be fresh.

        if ( is_array( $notoptions ) && isset( $notoptions[ $option ] ) ) {
                unset( $notoptions[ $option ] );
                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;
}

/**
 * Removes an option by name. Prevents removal of protected WordPress options.
 *
 * @since 1.2.0
 *
 * @global wpdb $wpdb WordPress database abstraction object.
 *
 * @param string $option Name of the option to delete. Expected to not be SQL-escaped.
 * @return bool True if the option was deleted, false otherwise.
 */
function delete_option( $option ) {
        global $wpdb;

        if ( is_scalar( $option ) ) {
                $option = trim( $option );
        }

        if ( empty( $option ) ) {
                return false;
        }

        wp_protect_special_option( $option );

        // Get the ID, if no ID then return.
        $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 ( ! wp_installing() ) {
                if ( 'yes' === $row->autoload ) {
                        $alloptions = wp_load_alloptions( true );
                        if ( is_array( $alloptions ) && isset( $alloptions[ $option ] ) ) {
                                unset( $alloptions[ $option ] );
                                wp_cache_set( 'alloptions', $alloptions, 'options' );
                        }
                } else {
                        wp_cache_delete( $option, 'options' );
                }
        }

        if ( $result ) {

                /**
                 * 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;
        }

        return false;
}

/**
 * Deletes a transient.
 *
 * @since 2.8.0
 *
 * @param string $transient Transient name. Expected to not be SQL-escaped.
 * @return bool True if the transient was deleted, false otherwise.
 */
function delete_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() || wp_installing() ) {
                $result = wp_cache_delete( $transient, 'transient' );
        } else {
                $option_timeout = '_transient_timeout_' . $transient;
                $option         = '_transient_' . $transient;
                $result         = delete_option( $option );

                if ( $result ) {
                        delete_option( $option_timeout );
                }
        }

        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;
}

/**
 * Retrieves the value of a transient.
 *
 * 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
 *
 * @param string $transient Transient name. Expected to not be SQL-escaped.
 * @return mixed Value of transient.
 */
function get_transient( $transient ) {

        /**
         * Filters the value of an existing transient before it is retrieved.
         *
         * The dynamic portion of the hook name, `$transient`, refers to the transient name.
         *
         * Returning a value other than false from the filter will short-circuit retrieval
         * and return that value instead.
         *
         * @since 2.8.0
         * @since 4.4.0 The `$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 that value.
         * @param string $transient     Transient name.
         */
        $pre = apply_filters( "pre_transient_{$transient}", false, $transient );

        if ( false !== $pre ) {
                return $pre;
        }

        if ( wp_using_ext_object_cache() || wp_installing() ) {
                $value = wp_cache_get( $transient, 'transient' );
        } else {
                $transient_option = '_transient_' . $transient;
                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;
                                $timeout           = get_option( $transient_timeout );
                                if ( false !== $timeout && $timeout < time() ) {
                                        delete_option( $transient_option );
                                        delete_option( $transient_timeout );
                                        $value = false;
                                }
                        }
                }

                if ( ! isset( $value ) ) {
                        $value = get_option( $transient_option );
                }
        }

        /**
         * 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 );
}

/**
 * Sets/updates the value of a transient.
 *
 * You do not need to serialize values. If the value needs to be serialized,
 * then it will be serialized before it is set.
 *
 * @since 2.8.0
 *
 * @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 True if the value was set, false otherwise.
 */
function set_transient( $transient, $value, $expiration = 0 ) {

        $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() || wp_installing() ) {
                $result = wp_cache_set( $transient, $value, 'transient', $expiration );
        } else {
                $transient_timeout = '_transient_timeout_' . $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_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_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 ) {

                /**
                 * 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;
}

/**
 * Deletes all expired transients.
 *
 * Note that this function won't do anything if an external object cache is in use.
 *
 * The multi-table delete syntax is used to delete the transient record
 * from table a, and the corresponding transient_timeout record from table b.
 *
 * @global wpdb $wpdb WordPress database abstraction object.
 *
 * @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() ) {
                // Single site 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
 * cookie exists (different browser used), adds the last saved cookie restoring
 * the settings.
 *
 * @since 2.7.0
 */
function wp_user_settings() {

        if ( ! is_admin() || wp_doing_ajax() ) {
                return;
        }

        $user_id = get_current_user_id();
        if ( ! $user_id ) {
                return;
        }

        if ( ! is_user_member_of_blog() ) {
                return;
        }

        $settings = (string) get_user_option( 'user-settings', $user_id );

        if ( isset( $_COOKIE[ 'wp-settings-' . $user_id ] ) ) {
                $cookie = preg_replace( '/[^A-Za-z0-9=&_]/', '', $_COOKIE[ 'wp-settings-' . $user_id ] );

                // No change or both empty.
                if ( $cookie == $settings ) {
                        return;
                }

                $last_saved = (int) get_user_option( 'user-settings-time', $user_id );
                $current    = isset( $_COOKIE[ 'wp-settings-time-' . $user_id ] ) ? preg_replace( '/[^0-9]/', '', $_COOKIE[ 'wp-settings-time-' . $user_id ] ) : 0;

                // The cookie is newer than the saved value. Update the user_option and leave the cookie as-is.
                if ( $current > $last_saved ) {
                        update_user_option( $user_id, 'user-settings', $cookie, false );
                        update_user_option( $user_id, 'user-settings-time', time() - 5, false );
                        return;
                }
        }

        // The cookie is not set in the current browser or the saved value is newer.
        $secure = ( 'https' === parse_url( admin_url(), PHP_URL_SCHEME ) );
        setcookie( 'wp-settings-' . $user_id, $settings, time() + YEAR_IN_SECONDS, SITECOOKIEPATH, '', $secure );
        setcookie( 'wp-settings-time-' . $user_id, time(), time() + YEAR_IN_SECONDS, SITECOOKIEPATH, '', $secure );
        $_COOKIE[ 'wp-settings-' . $user_id ] = $settings;
}

/**
 * Retrieves user interface setting value based on setting name.
 *
 * @since 2.7.0
 *
 * @param string       $name          The name of the setting.
 * @param string|false $default_value Optional. Default value to return when $name is not set. Default false.
 * @return mixed The last saved user setting or the default value/false if it doesn't exist.
 */
function get_user_setting( $name, $default_value = false ) {
        $all_user_settings = get_all_user_settings();

        return isset( $all_user_settings[ $name ] ) ? $all_user_settings[ $name ] : $default_value;
}

/**
 * Adds or updates user interface setting.
 *
 * Both `$name` and `$value` can contain only ASCII letters, numbers, hyphens, 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 $value The value for the setting.
 * @return bool|null True if set successfully, false otherwise.
 *                   Null if the current user is not a member of the site.
 */
function set_user_setting( $name, $value ) {
        if ( headers_sent() ) {
                return false;
        }

        $all_user_settings          = get_all_user_settings();
        $all_user_settings[ $name ] = $value;

        return wp_set_all_user_settings( $all_user_settings );
}

/**
 * Deletes 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 bool|null True if deleted successfully, false otherwise.
 *                   Null if the current user is not a member of the site.
 */
function delete_user_setting( $names ) {
        if ( headers_sent() ) {
                return false;
        }

        $all_user_settings = get_all_user_settings();
        $names             = (array) $names;
        $deleted           = false;

        foreach ( $names as $name ) {
                if ( isset( $all_user_settings[ $name ] ) ) {
                        unset( $all_user_settings[ $name ] );
                        $deleted = true;
                }
        }

        if ( $deleted ) {
                return wp_set_all_user_settings( $all_user_settings );
        }

        return false;
}

/**
 * Retrieves all user interface settings.
 *
 * @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;

        $user_id = get_current_user_id();
        if ( ! $user_id ) {
                return array();
        }

        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 ] );

                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 ) ) {
                        parse_str( $option, $user_settings );
                }
        }

        $_updated_user_settings = $user_settings;
        return $user_settings;
}

/**
 * Private. Sets all user interface settings.
 *
 * @since 2.8.0
 * @access private
 *
 * @global array $_updated_user_settings
 *
 * @param array $user_settings User settings.
 * @return bool|null True if set successfully, false if the current user could not be found.
 *                   Null if the current user is not a member of the site.
 */
function wp_set_all_user_settings( $user_settings ) {
        global $_updated_user_settings;

        $user_id = get_current_user_id();
        if ( ! $user_id ) {
                return false;
        }

        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 );

                if ( ! empty( $_name ) ) {
                        $settings .= $_name . '=' . $_value . '&';
                }
        }

        $settings = rtrim( $settings, '&' );
        parse_str( $settings, $_updated_user_settings );

        update_user_option( $user_id, 'user-settings', $settings, false );
        update_user_option( $user_id, 'user-settings-time', time(), false );

        return true;
}

/**
 * Deletes the user settings of the current user.
 *
 * @since 2.7.0
 */
function delete_all_user_settings() {
        $user_id = get_current_user_id();
        if ( ! $user_id ) {
                return;
        }

        update_user_option( $user_id, 'user-settings', '', false );
        setcookie( 'wp-settings-' . $user_id, ' ', time() - YEAR_IN_SECONDS, SITECOOKIEPATH );
}

/**
 * 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 the option to retrieve. Expected to not be SQL-escaped.
 * @param mixed  $default_value Optional. Value to return if the 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_value = false, $deprecated = true ) {
        return get_network_option( null, $option, $default_value );
}

/**
 * Adds 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 the 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 True if the option was added, false otherwise.
 */
function add_site_option( $option, $value ) {
        return add_network_option( null, $option, $value );
}

/**
 * Removes an 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 the option to delete. Expected to not be SQL-escaped.
 * @return bool True if the option was deleted, false otherwise.
 */
function delete_site_option( $option ) {
        return delete_network_option( null, $option );
}

/**
 * Updates 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 the option. Expected to not be SQL-escaped.
 * @param mixed  $value  Option value. Expected to not be SQL-escaped.
 * @return bool True if the value was updated, false otherwise.
 */
function update_site_option( $option, $value ) {
        return update_network_option( null, $option, $value );
}

/**
 * Retrieves a network's option value based on the option name.
 *
 * @since 4.4.0
 *
 * @see get_option()
 *
 * @global wpdb $wpdb WordPress database abstraction object.
 *
 * @param int    $network_id    ID of the network. Can be null to default to the current network ID.
 * @param string $option        Name of the option to retrieve. Expected to not be SQL-escaped.
 * @param mixed  $default_value Optional. Value to return if the option doesn't exist. Default false.
 * @return mixed Value set for the option.
 */
function get_network_option( $network_id, $option, $default_value = 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();
        }

        /**
         * Filters the value of an existing network option before it is retrieved.
         *
         * The dynamic portion of the hook name, `$option`, refers to the option name.
         *
         * Returning a value other than false from the filter will short-circuit retrieval
         * and return that 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 `$network_id` parameter was added.
         * @since 4.9.0 The `$default_value` parameter was added.
         *
         * @param mixed  $pre_option    The value to return instead of the option value. This differs from
         *                              `$default_value`, which is used as the fallback value in the event
         *                              the option doesn't exist elsewhere in get_network_option().
         *                              Default false (to skip past the short-circuit).
         * @param string $option        Option name.
         * @param int    $network_id    ID of the network.
         * @param mixed  $default_value The fallback value to return if the option does not exist.
         *                              Default false.
         */
        $pre = apply_filters( "pre_site_option_{$option}", false, $option, $network_id, $default_value );

        if ( false !== $pre ) {
                return $pre;
        }

        // Prevent non-existent options from triggering multiple queries.
        $notoptions_key = "$network_id:notoptions";
        $notoptions     = wp_cache_get( $notoptions_key, 'site-options' );

        if ( is_array( $notoptions ) && isset( $notoptions[ $option ] ) ) {

                /**
                 * Filters the value of 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_value 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_value, $option, $network_id );
        }

        if ( ! is_multisite() ) {
                /** This filter is documented in wp-includes/option.php */
                $default_value = apply_filters( 'default_site_option_' . $option, $default_value, $option, $network_id );
                $value         = get_option( $option, $default_value );
        } else {
                $cache_key = "$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, $network_id ) );

                        // Has to be get_row() instead of get_var() because of funkiness with 0, false, null values.
                        if ( is_object( $row ) ) {
                                $value = $row->meta_value;
                                $value = maybe_unserialize( $value );
                                wp_cache_set( $cache_key, $value, 'site-options' );
                        } else {
                                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, $option, $network_id );
                        }
                }
        }

        if ( ! is_array( $notoptions ) ) {
                $notoptions = array();
                wp_cache_set( $notoptions_key, $notoptions, 'site-options' );
        }

        /**
         * 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 );
}

/**
 * Adds a new network option.
 *
 * Existing options will not be updated.
 *
 * @since 4.4.0
 *
 * @see add_option()
 *
 * @global wpdb $wpdb WordPress database abstraction object.
 *
 * @param int    $network_id ID of the network. Can be null to default to the current network ID.
 * @param string $option     Name of the 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 True if the option was added, false otherwise.
 */
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 );

        /**
         * 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, '', 'no' );
        } else {
                $cache_key = "$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_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'    => $network_id,
                                'meta_key'   => $option,
                                'meta_value' => $serialized_value,
                        )
                );

                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 ] );
                        wp_cache_set( $notoptions_key, $notoptions, 'site-options' );
                }
        }

        if ( $result ) {

                /**
                 * 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 a network option by name.
 *
 * @since 4.4.0
 *
 * @see delete_option()
 *
 * @global wpdb $wpdb WordPress database abstraction object.
 *
 * @param int    $network_id ID of the network. Can be null to default to the current network ID.
 * @param string $option     Name of the option to delete. Expected to not be SQL-escaped.
 * @return bool True if the option was deleted, false otherwise.
 */
function delete_network_option( $network_id, $option ) {
        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();
        }

        /**
         * 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, $network_id ) );
                if ( is_null( $row ) || ! $row->meta_id ) {
                        return false;
                }
                $cache_key = "$network_id:$option";
                wp_cache_delete( $cache_key, 'site-options' );

                $result = $wpdb->delete(
                        $wpdb->sitemeta,
                        array(
                                'meta_key' => $option,
                                'site_id'  => $network_id,
                        )
                );
        }

        if ( $result ) {

                /**
                 * 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;
}

/**
 * Updates the value of a network option that was already added.
 *
 * @since 4.4.0
 *
 * @see update_option()
 *
 * @global wpdb $wpdb WordPress database abstraction object.
 *
 * @param int    $network_id ID of the network. Can be null to default to the current network ID.
 * @param string $option     Name of the option. Expected to not be SQL-escaped.
 * @param mixed  $value      Option value. Expected to not be SQL-escaped.
 * @return bool True if the value was updated, false otherwise.
 */
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_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 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/44956
         */
        if ( $value === $old_value || maybe_serialize( $value ) === maybe_serialize( $old_value ) ) {
                return false;
        }

        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 ] );
                wp_cache_set( $notoptions_key, $notoptions, 'site-options' );
        }

        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'  => $network_id,
                                'meta_key' => $option,
                        )
                );

                if ( $result ) {
                        $cache_key = "$network_id:$option";
                        wp_cache_set( $cache_key, $value, 'site-options' );
                }
        }

        if ( $result ) {

                /**
                 * 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;
}

/**
 * Deletes a site transient.
 *
 * @since 2.9.0
 *
 * @param string $transient Transient name. Expected to not be SQL-escaped.
 * @return bool True if the transient was deleted, false otherwise.
 */
function delete_site_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() || wp_installing() ) {
                $result = wp_cache_delete( $transient, 'site-transient' );
        } else {
                $option_timeout = '_site_transient_timeout_' . $transient;
                $option         = '_site_transient_' . $transient;
                $result         = delete_site_option( $option );

                if ( $result ) {
                        delete_site_option( $option_timeout );
                }
        }

        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;
}

/**
 * Retrieves the value of a site transient.
 *
 * If the transient does not exist, does not have a value, or has expired,
 * then the return value will be false.
 *
 * @since 2.9.0
 *
 * @see get_transient()
 *
 * @param string $transient Transient name. Expected to not be SQL-escaped.
 * @return mixed Value of transient.
 */
function get_site_transient( $transient ) {

        /**
         * Filters the value of an existing site transient before it is retrieved.
         *
         * The dynamic portion of the hook name, `$transient`, refers to the transient name.
         *
         * Returning a value other than boolean false will short-circuit retrieval and
         * return that value instead.
         *
         * @since 2.9.0
         * @since 4.4.0 The `$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 that value.
         * @param string $transient          Transient name.
         */
        $pre = apply_filters( "pre_site_transient_{$transient}", false, $transient );

        if ( false !== $pre ) {
                return $pre;
        }

        if ( wp_using_ext_object_cache() || wp_installing() ) {
                $value = wp_cache_get( $transient, 'site-transient' );
        } else {
                // Core transients that do not have a timeout. Listed here so querying timeouts can be avoided.
                $no_timeout       = array( 'update_core', 'update_plugins', 'update_themes' );
                $transient_option = '_site_transient_' . $transient;
                if ( ! in_array( $transient, $no_timeout, true ) ) {
                        $transient_timeout = '_site_transient_timeout_' . $transient;
                        $timeout           = get_site_option( $transient_timeout );
                        if ( false !== $timeout && $timeout < time() ) {
                                delete_site_option( $transient_option );
                                delete_site_option( $transient_timeout );
                                $value = false;
                        }
                }

                if ( ! isset( $value ) ) {
                        $value = get_site_option( $transient_option );
                }
        }

        /**
         * 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 );
}

/**
 * Sets/updates the value of a site transient.
 *
 * You do not need to serialize values. If the value needs to be serialized,
 * then it will be serialized before it is set.
 *
 * @since 2.9.0
 *
 * @see set_transient()
 *
 * @param string $transient  Transient name. Expected to not be SQL-escaped. Must be
 *                           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 (no expiration).
 * @return bool True if the value was set, false otherwise.
 */
function set_site_transient( $transient, $value, $expiration = 0 ) {

        /**
         * 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() || wp_installing() ) {
                $result = wp_cache_set( $transient, $value, 'site-transient', $expiration );
        } else {
                $transient_timeout = '_site_transient_timeout_' . $transient;
                $option            = '_site_transient_' . $transient;

                if ( false === get_site_option( $option ) ) {
                        if ( $expiration ) {
                                add_site_option( $transient_timeout, time() + $expiration );
                        }
                        $result = add_site_option( $option, $value );
                } else {
                        if ( $expiration ) {
                                update_site_option( $transient_timeout, time() + $expiration );
                        }
                        $result = update_site_option( $option, $value );
                }
        }

        if ( $result ) {

                /**
                 * 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;
}

/**
 * Registers 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
 * @since 6.0.1 The `show_on_front`, `page_on_front`, and `page_for_posts` options were added.
 */
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(
                'reading',
                'show_on_front',
                array(
                        'show_in_rest' => true,
                        'type'         => 'string',
                        'description'  => __( 'What to show on the front page' ),
                )
        );

        register_setting(
                'reading',
                'page_on_front',
                array(
                        'show_in_rest' => true,
                        'type'         => 'integer',
                        'description'  => __( 'The ID of the page that should be displayed on the front page' ),
                )
        );

        register_setting(
                'reading',
                'page_for_posts',
                array(
                        'show_in_rest' => true,
                        'type'         => 'integer',
                        'description'  => __( 'The ID of the page that should display the latest posts' ),
                )
        );

        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 submit comments on new posts.' ),
                )
        );
}

/**
 * Registers a setting and its data.
 *
 * @since 2.7.0
 * @since 3.0.0 The `misc` option group was deprecated.
 * @since 3.5.0 The `privacy` option group was deprecated.
 * @since 4.7.0 `$args` can be passed to set flags on the setting, similar to `register_meta()`.
 * @since 5.5.0 `$new_whitelist_options` was renamed to `$new_allowed_options`.
 *              Please consider writing more inclusive code.
 *
 * @global array $new_allowed_options
 * @global array $wp_registered_settings
 *
 * @param string $option_group A settings group name. Should correspond to an allowed option key name.
 *                             Default allowed option key names include 'general', 'discussion', 'media',
 *                             'reading', 'writing', and 'options'.
 * @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', 'number', 'array', and 'object'.
 *     @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|array $show_in_rest      Whether data associated with this setting should be included in the REST API.
 *                                         When registering complex settings, this argument may optionally be an
 *                                         array with a 'schema' key.
 *     @type mixed      $default           Default value when calling `get_option()`.
 * }
 */
function register_setting( $option_group, $option_name, $args = array() ) {
        global $new_allowed_options, $wp_registered_settings;

        /*
         * In 5.5.0, the `$new_whitelist_options` global variable was renamed to `$new_allowed_options`.
         * Please consider writing more inclusive code.
         */
        $GLOBALS['new_whitelist_options'] = &$new_allowed_options;

        $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 );

        // Require an item schema when registering settings with an array type.
        if ( false !== $args['show_in_rest'] && 'array' === $args['type'] && ( ! is_array( $args['show_in_rest'] ) || ! isset( $args['show_in_rest']['schema']['items'] ) ) ) {
                _doing_it_wrong( __FUNCTION__, __( 'When registering an "array" setting to show in the REST API, you must specify the schema for each array item in "show_in_rest.schema.items".' ), '5.4.0' );
        }

        if ( ! is_array( $wp_registered_settings ) ) {
                $wp_registered_settings = array();
        }

        if ( 'misc' === $option_group ) {
                _deprecated_argument(
                        __FUNCTION__,
                        '3.0.0',
                        sprintf(
                                /* translators: %s: misc */
                                __( '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(
                                /* translators: %s: privacy */
                                __( 'The "%s" options group has been removed. Use another settings group.' ),
                                'privacy'
                        )
                );
                $option_group = 'reading';
        }

        $new_allowed_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 );
        }

        /**
         * Fires immediately before the setting is registered but after its filters are in place.
         *
         * @since 5.5.0
         *
         * @param string $option_group Setting group.
         * @param string $option_name  Setting name.
         * @param array  $args         Array of setting registration arguments.
         */
        do_action( 'register_setting', $option_group, $option_name, $args );

        $wp_registered_settings[ $option_name ] = $args;
}

/**
 * Unregisters a setting.
 *
 * @since 2.7.0
 * @since 4.7.0 `$sanitize_callback` was deprecated. The callback from `register_setting()` is now used instead.
 * @since 5.5.0 `$new_whitelist_options` was renamed to `$new_allowed_options`.
 *              Please consider writing more inclusive code.
 *
 * @global array $new_allowed_options
 * @global array $wp_registered_settings
 *
 * @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   Optional. Deprecated.
 */
function unregister_setting( $option_group, $option_name, $deprecated = '' ) {
        global $new_allowed_options, $wp_registered_settings;

        /*
         * In 5.5.0, the `$new_whitelist_options` global variable was renamed to `$new_allowed_options`.
         * Please consider writing more inclusive code.
         */
        $GLOBALS['new_whitelist_options'] = &$new_allowed_options;

        if ( 'misc' === $option_group ) {
                _deprecated_argument(
                        __FUNCTION__,
                        '3.0.0',
                        sprintf(
                                /* translators: %s: misc */
                                __( '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(
                                /* translators: %s: privacy */
                                __( 'The "%s" options group has been removed. Use another settings group.' ),
                                'privacy'
                        )
                );
                $option_group = 'reading';
        }

        $pos = array_search( $option_name, (array) $new_allowed_options[ $option_group ], true );

        if ( false !== $pos ) {
                unset( $new_allowed_options[ $option_group ][ $pos ] );
        }

        if ( '' !== $deprecated ) {
                _deprecated_argument(
                        __FUNCTION__,
                        '4.7.0',
                        sprintf(
                                /* translators: 1: $sanitize_callback, 2: register_setting() */
                                __( '%1$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'] );
                }

                // Remove the default filter if a default was provided during registration.
                if ( array_key_exists( 'default', $wp_registered_settings[ $option_name ] ) ) {
                        remove_filter( "default_option_{$option_name}", 'filter_default_option', 10 );
                }

                /**
                 * Fires immediately before the setting is unregistered and after its filters have been removed.
                 *
                 * @since 5.5.0
                 *
                 * @param string $option_group Setting group.
                 * @param string $option_name  Setting name.
                 */
                do_action( 'unregister_setting', $option_group, $option_name );

                unset( $wp_registered_settings[ $option_name ] );
        }
}

/**
 * Retrieves an array of registered settings.
 *
 * @since 4.7.0
 *
 * @global array $wp_registered_settings
 *
 * @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;
}

/**
 * Filters 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_value  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_value, $option, $passed_default ) {
        if ( $passed_default ) {
                return $default_value;
        }

        $registered = get_registered_settings();
        if ( empty( $registered[ $option ] ) ) {
                return $default_value;
        }

        return $registered[ $option ]['default'];
}