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Source code

function retrieve_widgets($theme_changed = false) {

	global $wp_registered_widget_updates, $wp_registered_sidebars, $sidebars_widgets, $wp_registered_widgets;



	$registered_sidebar_keys = array_keys( $wp_registered_sidebars );

	$orphaned = 0;



	$old_sidebars_widgets = get_theme_mod( 'sidebars_widgets' );

	if ( is_array( $old_sidebars_widgets ) ) {

		// time() that sidebars were stored is in $old_sidebars_widgets['time']

		$_sidebars_widgets = $old_sidebars_widgets['data'];

		remove_theme_mod( 'sidebars_widgets' );



		foreach ( $_sidebars_widgets as $sidebar => $widgets ) {

			if ( 'wp_inactive_widgets' == $sidebar || 'orphaned_widgets' == substr( $sidebar, 0, 16 ) )

				continue;



			if ( !in_array( $sidebar, $registered_sidebar_keys ) ) {

				$_sidebars_widgets['orphaned_widgets_' . ++$orphaned] = $widgets;

				unset( $_sidebars_widgets[$sidebar] );

			}

		}

	} else {

		if ( empty( $sidebars_widgets ) )

			return;



		unset( $sidebars_widgets['array_version'] );



		$old = array_keys($sidebars_widgets);

		sort($old);

		sort($registered_sidebar_keys);



		if ( $old == $registered_sidebar_keys )

			return;



		$_sidebars_widgets = array(

			'wp_inactive_widgets' => !empty( $sidebars_widgets['wp_inactive_widgets'] ) ? $sidebars_widgets['wp_inactive_widgets'] : array()

		);



		unset( $sidebars_widgets['wp_inactive_widgets'] );



		foreach ( $wp_registered_sidebars as $id => $settings ) {

			if ( $theme_changed ) {

				$_sidebars_widgets[$id] = array_shift( $sidebars_widgets );

			} else {

				// no theme change, grab only sidebars that are currently registered

				if ( isset( $sidebars_widgets[$id] ) ) {

					$_sidebars_widgets[$id] = $sidebars_widgets[$id];

					unset( $sidebars_widgets[$id] );

				}

			}

		}



		foreach ( $sidebars_widgets as $val ) {

			if ( is_array($val) && ! empty( $val ) )

				$_sidebars_widgets['orphaned_widgets_' . ++$orphaned] = $val;

		}

	}



	// discard invalid, theme-specific widgets from sidebars

	$shown_widgets = array();



	foreach ( $_sidebars_widgets as $sidebar => $widgets ) {

		if ( !is_array($widgets) )

			continue;



		$_widgets = array();

		foreach ( $widgets as $widget ) {

			if ( isset($wp_registered_widgets[$widget]) )

				$_widgets[] = $widget;

		}



		$_sidebars_widgets[$sidebar] = $_widgets;

		$shown_widgets = array_merge($shown_widgets, $_widgets);

	}



	$sidebars_widgets = $_sidebars_widgets;

	unset($_sidebars_widgets, $_widgets);



	// find hidden/lost multi-widget instances

	$lost_widgets = array();

	foreach ( $wp_registered_widgets as $key => $val ) {

		if ( in_array($key, $shown_widgets, true) )

			continue;



		$number = preg_replace('/.+?-([0-9]+)$/', '$1', $key);



		if ( 2 > (int) $number )

			continue;



		$lost_widgets[] = $key;

	}



	$sidebars_widgets['wp_inactive_widgets'] = array_merge($lost_widgets, (array) $sidebars_widgets['wp_inactive_widgets']);

	wp_set_sidebars_widgets($sidebars_widgets);



	return $sidebars_widgets;

}