WebEngine-specific: add/expand TODO comments

articleview.cc

@@ -2254,6 +2254,8 @@ QString ArticleView::toHtml()
   return ui.definition->page()->mainFrame()->toHtml();
 #else
   // TODO (Qt WebEngine): port this function and its uses to asynchronous QWebEnginePage::toHtml().
+  // This function is called only from MainWindow::on_saveArticle_triggered(). The Save Article feature can be
+  // implemented differently using QWebEnginePage::save(). Compare the results of the two approaches and select one.
   return QString();
 #endif
 }

articlewebpage.cc

@@ -52,6 +52,16 @@ bool ArticleWebPage::acceptNavigationRequest( QUrl const & url, NavigationType t
   Q_UNUSED( isMainFrame )
   if( type != NavigationTypeLinkClicked )
     return true;
+
+  // TODO (Qt WebEngine): when a link that does not load a new page is clicked before the current page is fully loaded,
+  // the view stops updating because of QTBUG-106580. And then only the beginning of the last displayed article may be
+  // visible, a few bottommost articles may be altogether missing from the page. A possible workaround is to replace the
+  // anchor element (<a>) of each such link with a button (possibly image button) and pass the link's URL to ArticleView
+  // via Qt WebChannel: onclick="gdArticleView.onJsLinkClicked('<url>');". Such a replacement is very time-consuming for
+  // a workaround: each audio, video, other resource or external link in every dictionary format has to be replaced.
+  // One more downside of this workaround is that the buttons won't work in saved articles (this in turn can be worked
+  // around by falling back to assigning the URL to window.location.href if gdArticleView is falsy in a new
+  // gdLinkClicked(url) helper function).
   emit linkClicked( url );
   return false;
 }

mainwindow.cc

@@ -146,6 +146,20 @@ void setupWebEngineProfile( QWebEngineProfile & webEngineProfile, ArticleNetwork
   // TODO (Qt WebEngine): should the maximum size of the HTTP cache and whether
   // it is cleared on exit be configurable similarly to the network cache?
 
+  // TODO (Qt WebEngine): in the Qt WebEngine version articleNetMgr's cache is useful only for downloaded files,
+  // because the page itself is stored separately in the Qt WebEngine profile's cache. In the interest of
+  // reusing the Qt WebEngine profile's cache for both loading pages and downloading files,
+  // Dictionary::WebMultimediaDownload could call QWebEnginePage::download() instead of
+  // QNetworkAccessManager::get() to retrieve files from network. articleNetMgr's cache would become
+  // practically useless then and could be restricted to the Qt WebKit version along with its configuration UI.
+
+  // TODO (Qt WebEngine): should the configuration UI allow disabling persistent cookies?
+  // Cookies are never stored on disk in the Qt WebKit version according to the documentation for QNetworkCookieJar:
+  // > QNetworkCookieJar does not implement permanent storage: it only keeps the cookies in memory. Once the
+  // > QNetworkCookieJar object is deleted, all cookies it held will be discarded as well. If you want to save the
+  // > cookies, you should derive from this class and implement the saving to disk to your own storage format.
+  // Should the persistent cookies be disabled by default in the Qt WebEngine version too?
+
   articleNetMgr.setStreamingDeviceWorkarounds( computeStreamingDeviceWorkarounds( webEngineProfile ) );
 
   auto * const handler = new ArticleUrlSchemeHandler( articleNetMgr );