BookStack\Http\Controllers\PageController::showRevisionChanges PHP Метод

    public function showRevisionChanges($bookSlug, $pageSlug, $revisionId)
    {
        $book = $this->bookRepo->getBySlug($bookSlug);
        $page = $this->pageRepo->getBySlug($pageSlug, $book->id);
        $revision = $this->pageRepo->getRevisionById($revisionId);
        $prev = $revision->getPrevious();
        $prevContent = $prev === null ? '' : $prev->html;
        $diff = (new Htmldiff())->diff($prevContent, $revision->html);
        $page->fill($revision->toArray());
        $this->setPageTitle('Page Revision For ' . $page->getShortName());
        return view('pages/revision', ['page' => $page, 'book' => $book, 'diff' => $diff]);
    }