removeHooksIfLibraryGone() {
			//Cancel all further actions if the current version of PUC has been deleted or overwritten
			//by a different version during the upgrade. If we try to do anything more in that situation,
			//we could trigger a fatal error by trying to autoload a deleted class.
			clearstatcache();
			if ( !file_exists(__FILE__) ) {
				$this->removeHooks();
				$this->updateChecker->removeHooks();
			}
		}

		/**
		 * Runs upon the WP action upgrader_process_complete.
		 *
		 * We look at the parameters to decide whether to call maybeCheckForUpdates() or not.
		 * We also check if the update checker has been removed by the update.
		 *
		 * @param \WP_Upgrader $upgrader  WP_Upgrader instance
		 * @param array $upgradeInfo extra information about the upgrade
		 */
		public function upgraderProcessComplete(
			/** @noinspection PhpUnusedParameterInspection */
			$upgrader, $upgradeInfo
		) {
			//Sanity check and limitation to relevant types.
			if (
				!is_array($upgradeInfo) || !isset($upgradeInfo['type'], $upgradeInfo['action'])
				|| 'update' !== $upgradeInfo['action'] || !in_array($upgradeInfo['type'], array('plugin', 'theme'))
			) {
				return;
			}

			//Filter out notifications of upgrades that should have no bearing upon whether or not our
			//current info is up-to-date.
			if ( is_a($this->updateChecker, Theme\UpdateChecker::class) ) {
				if ( 'theme' !== $upgradeInfo['type'] || !isset($upgradeInfo['themes']) ) {
					return;
				}

				//Letting too many things going through for checks is not a real problem, so we compare widely.
				if ( !in_array(
					strtolower($this->updateChecker->directoryName),
					array_map('strtolower', $upgradeInfo['themes'])
				) ) {
					return;
				}
			}

			if ( is_a($this->updateChecker, Plugin\UpdateChecker::class) ) {
				if ( 'plugin' !== $upgradeInfo['type'] || !isset($upgradeInfo['plugins']) ) {
					return;
				}

				//Themes pass in directory names in the information array, but plugins use the relative plugin path.
				if ( !in_array(
					strtolower($this->updateChecker->directoryName),
					array_map('dirname', array_map('strtolower', $upgradeInfo['plugins']))
				) ) {
					return;
				}
			}

			$this->maybeCheckForUpdates();
		}

		/**
		 * Check for updates if the configured check interval has already elapsed.
		 * Will use a shorter check interval on certain admin pages like "Dashboard -> Updates" or when doing cron.
		 *
		 * You can override the default behaviour by using the "puc_check_now-$slug" filter.
		 * The filter callback will be passed three parameters:
		 *     - Current decision. TRUE = check updates now, FALSE = don't check now.
		 *     - Last check time as a Unix timestamp.
		 *     - Configured check period in hours.
		 * Return TRUE to check for updates immediately, or FALSE to cancel.
		 *
		 * This method is declared public because it's a hook callback. Calling it directly is not recommended.
		 */
		public function maybeCheckForUpdates() {
			if ( empty($this->checkPeriod) ){
				return;
			}

			$state = $this->updateChecker->getUpdateState();
			$shouldCheck = ($state->timeSinceLastCheck() >= $this->getEffectiveCheckPeriod());

			if ( $shouldCheck ) {
				//Sanity check: Do not proceed if one of the critical classes is missing.
				//That can happen - theoretically and extremely rarely - if maybeCoreUpdate()
				//is called before the old version of our plugin has been fully deleted, or
				//called from an independent AJAX request during deletion.
				if ( !(
					class_exists(Utils::class)
					&& class_exists(Metadata::class)
					&& class_exists(Plugin\Update::class)
					&& class_exists(Theme\Update::class)
				) ) {
					return;
				}
			}

			//Let plugin authors substitute their own algorithm.
			$shouldCheck = apply_filters(
				$this->updateChecker->getUniqueName('check_now'),
				$shouldCheck,
				$state->getLastCheck(),
				$this->checkPeriod
			);

			if ( $shouldCheck ) {
				$this->updateChecker->checkForUpdates();
			}
		}

		/**
		 * Calculate the actual check period based on the current status and environment.
		 *
		 * @return int Check period in seconds.
		 */
		protected function getEffectiveCheckPeriod() {
			$currentFilter = current_filter();
			if ( in_array($currentFilter, array('load-update-core.php', 'upgrader_process_complete')) ) {
				//Check more often when the user visits "Dashboard -> Updates" or does a bulk update.
				$period = 60;
			} else if ( in_array($currentFilter, $this->hourlyCheckHooks) ) {
				//Also check more often on /wp-admin/update.php and the "Plugins" or "Themes" page.
				$period = 3600;
			} else if ( $this->throttleRedundantChecks && ($this->updateChecker->getUpdate() !== null) ) {
				//Check less frequently if it's already known that an update is available.
				$period = $this->throttledCheckPeriod * 3600;
			} else if ( defined('DOING_CRON') && constant('DOING_CRON') ) {
				//WordPress cron schedules are not exact, so let's do an update check even
				//if slightly less than $checkPeriod hours have elapsed since the last check.
				$cronFuzziness = 20 * 60;
				$period = $this->checkPeriod * 3600 - $cronFuzziness;
			} else {
				$period = $this->checkPeriod * 3600;
			}

			return $period;
		}

		/**
		 * Add our custom schedule to the array of Cron schedules used by WP.
		 *
		 * @param array $schedules
		 * @return array
		 */
		public function _addCustomSchedule($schedules) {
			if ( $this->checkPeriod && ($this->checkPeriod > 0) ){
				$scheduleName = 'every' . $this->checkPeriod . 'hours';
				$schedules[$scheduleName] = array(
					'interval' => $this->checkPeriod * 3600,
					'display' => sprintf('Every %d hours', $this->checkPeriod),
				);
			}
			return $schedules;
		}

		/**
		 * Remove the scheduled cron event that the library uses to check for updates.
		 *
		 * @return void
		 */
		public function removeUpdaterCron() {
			wp_clear_scheduled_hook($this->cronHook);
		}

		/**
		 * Get the name of the update checker's WP-cron hook. Mostly useful for debugging.
		 *
		 * @return string
		 */
		public function getCronHookName() {
			return $this->cronHook;
		}

		/**
		 * Remove most hooks added by the scheduler.
		 */
		public function removeHooks() {
			remove_filter('cron_schedules', array($this, '_addCustomSchedule'));
			remove_action('admin_init', array($this, 'maybeCheckForUpdates'));
			remove_action('load-update-core.php', array($this, 'maybeCheckForUpdates'));

			if ( $this->cronHook !== null ) {
				remove_action($this->cronHook, array($this, 'maybeCheckForUpdates'));
			}
			if ( !empty($this->hourlyCheckHooks) ) {
				foreach ($this->hourlyCheckHooks as $hook) {
					remove_action($hook, array($this, 'maybeCheckForUpdates'));
				}
			}
		}
	}

endif;