更新一个已经添加的选项的值。

你不需要对值进行序列化。如果值需要序列化，那么在插入数据库之前，它将被序列化。记住，资源不能被序列化或作为选项添加。

如果该选项不存在，它将被创建。

这个功能被设计为在有无登录用户的情况下都能工作。在安全方面，插件开发者应该在更新任何选项之前检查当前用户的能力。

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;
}