protected function buildPages()
    {
        $this->sort = [];

        /** @var Config $config */
        $config = $this->grav['config'];

        /** @var Language $language */
        $language = $this->grav['language'];

        /** @var UniformResourceLocator $locator */
        $locator = $this->grav['locator'];

        $pages_dir = $locator->findResource('page://');

        if ($config->get('system.cache.enabled')) {
            /** @var Cache $cache */
            $cache = $this->grav['cache'];
            /** @var Taxonomy $taxonomy */
            $taxonomy = $this->grav['taxonomy'];

            // how should we check for last modified? Default is by file
            switch ($this->check_method) {
                case 'none':
                case 'off':
                    $hash = 0;
                    break;
                case 'folder':
                    $hash = Folder::lastModifiedFolder($pages_dir);
                    break;
                case 'hash':
                    $hash = Folder::hashAllFiles($pages_dir);
                    break;
                default:
                    $hash = Folder::lastModifiedFile($pages_dir);
            }

            $this->pages_cache_id = md5($pages_dir . $hash . $language->getActive() . $config->checksum());

            list($this->instances, $this->routes, $this->children, $taxonomy_map, $this->sort) = $cache->fetch($this->pages_cache_id);
            if (!$this->instances) {
                $this->grav['debugger']->addMessage('Page cache missed, rebuilding pages..');

                // recurse pages and cache result
                $this->resetPages($pages_dir);

            } else {
                // If pages was found in cache, set the taxonomy
                $this->grav['debugger']->addMessage('Page cache hit.');
                $taxonomy->taxonomy($taxonomy_map);
            }
        } else {
            $this->recurse($pages_dir);
            $this->buildRoutes();
        }
    }