Source

File: wp-includes/class-wp-customize-widgets.php

public function call_widget_update( $widget_id ) {
		global $wp_registered_widget_updates, $wp_registered_widget_controls;

		$setting_id = $this->get_setting_id( $widget_id );

		/*
		 * Make sure that other setting changes have previewed since this widget
		 * may depend on them (e.g. Menus being present for Navigation Menu widget).
		 */
		if ( ! did_action( 'customize_preview_init' ) ) {
			foreach ( $this->manager->settings() as $setting ) {
				if ( $setting->id !== $setting_id ) {
					$setting->preview();
				}
			}
		}

		$this->start_capturing_option_updates();
		$parsed_id   = $this->parse_widget_id( $widget_id );
		$option_name = 'widget_' . $parsed_id['id_base'];

		/*
		 * If a previously-sanitized instance is provided, populate the input vars
		 * with its values so that the widget update callback will read this instance
		 */
		$added_input_vars = array();
		if ( ! empty( $_POST['sanitized_widget_setting'] ) ) {
			$sanitized_widget_setting = json_decode( $this->get_post_value( 'sanitized_widget_setting' ), true );
			if ( false === $sanitized_widget_setting ) {
				$this->stop_capturing_option_updates();
				return new WP_Error( 'widget_setting_malformed' );
			}

			$instance = $this->sanitize_widget_instance( $sanitized_widget_setting );
			if ( is_null( $instance ) ) {
				$this->stop_capturing_option_updates();
				return new WP_Error( 'widget_setting_unsanitized' );
			}

			if ( ! is_null( $parsed_id['number'] ) ) {
				$value                         = array();
				$value[ $parsed_id['number'] ] = $instance;
				$key                           = 'widget-' . $parsed_id['id_base'];
				$_REQUEST[ $key ]              = wp_slash( $value );
				$_POST[ $key ]                 = $_REQUEST[ $key ];
				$added_input_vars[]            = $key;
			} else {
				foreach ( $instance as $key => $value ) {
					$_REQUEST[ $key ]   = wp_slash( $value );
					$_POST[ $key ]      = $_REQUEST[ $key ];
					$added_input_vars[] = $key;
				}
			}
		}

		// Invoke the widget update callback.
		foreach ( (array) $wp_registered_widget_updates as $name => $control ) {
			if ( $name === $parsed_id['id_base'] && is_callable( $control['callback'] ) ) {
				ob_start();
				call_user_func_array( $control['callback'], $control['params'] );
				ob_end_clean();
				break;
			}
		}

		// Clean up any input vars that were manually added.
		foreach ( $added_input_vars as $key ) {
			unset( $_POST[ $key ] );
			unset( $_REQUEST[ $key ] );
		}

		// Make sure the expected option was updated.
		if ( 0 !== $this->count_captured_options() ) {
			if ( $this->count_captured_options() > 1 ) {
				$this->stop_capturing_option_updates();
				return new WP_Error( 'widget_setting_too_many_options' );
			}

			$updated_option_name = key( $this->get_captured_options() );
			if ( $updated_option_name !== $option_name ) {
				$this->stop_capturing_option_updates();
				return new WP_Error( 'widget_setting_unexpected_option' );
			}
		}

		// Obtain the widget instance.
		$option = $this->get_captured_option( $option_name );
		if ( null !== $parsed_id['number'] ) {
			$instance = $option[ $parsed_id['number'] ];
		} else {
			$instance = $option;
		}

		/*
		 * Override the incoming $_POST['customized'] for a newly-created widget's
		 * setting with the new $instance so that the preview filter currently
		 * in place from WP_Customize_Setting::preview() will use this value
		 * instead of the default widget instance value (an empty array).
		 */
		$this->manager->set_post_value( $setting_id, $this->sanitize_widget_js_instance( $instance ) );

		// Obtain the widget control with the updated instance in place.
		ob_start();
		$form = $wp_registered_widget_controls[ $widget_id ];
		if ( $form ) {
			call_user_func_array( $form['callback'], $form['params'] );
		}
		$form = ob_get_clean();

		$this->stop_capturing_option_updates();

		return compact( 'instance', 'form' );
	}