bp_document_update_document_privacy( $folder )

function bp_document_update_document_privacy( &$folder ) {

	if ( ! empty( $folder->id ) ) {

		$privacy      = $folder->privacy;
		$document_ids = BP_Document::get_folder_document_ids( $folder->id );
		$activity_ids = array();

		if ( ! empty( $document_ids ) ) {
			foreach ( $document_ids as $document ) {
				$document_obj          = new BP_Document( $document );
				$document_obj->privacy = $privacy;
				$document_obj->save();

				$attachment_id    = $document_obj->attachment_id;
				$main_activity_id = get_post_meta( $attachment_id, 'bp_document_parent_activity_id', true );

				if ( ! empty( $main_activity_id ) ) {
					$activity_ids[] = $main_activity_id;
				}
			}
		}

		if ( bp_is_active( 'activity' ) && ! empty( $activity_ids )  ) {
			foreach ( $activity_ids as $activity_id ) {
				$activity = new BP_Activity_Activity( $activity_id );

				if ( ! empty( $activity ) ) {
					$activity->privacy = $privacy;
					$activity->save();
				}
			}
		}
	}
}