fixed loading of stylesheet if there is already some sheet loaded

resources/docs/Documentation.md

@@ -380,6 +380,7 @@ The other mode is that user data folder is placed in subfolder `data4` in the sa
 #### <a id="userd-plac"></a>`%data%` placeholder
 RSS Guard stores its data and settings in single folder. What exact folder it is is described [here](#portable-user-data). RSS Guard allows you to use the folder programmatically in some special contexts via `%data%` placeholder. You can use this placeholder in these RSS Guard contexts:
 * Contents of your [message filters](Message-filters.md) - you can therefore place some scripts under your user data folder and include it via `JavaScript` into your message filter.
+* Contents of each file included in your custom [skins](#skin). Note that in this case, the semantics of `%data%` are little changed and `%data%` points directly to base folder of your skin.
 * `source` and `post-process script` attributes of for [scraping](#scrap) feed - you can use the placeholder to load scripts to generate/process feed from user data folder.
 * Notifications also support the placeholder in path to audio files which are to be played when some event happens. For example you could place audio files in your data folder and then use them in notification with `%data%\audio\new-messages.wav`. See more about notifications [here](#notif).
 

src/librssguard/miscellaneous/skinfactory.cpp

@@ -42,8 +42,14 @@ void SkinFactory::loadCurrentSkin() {
 
 void SkinFactory::loadSkinFromData(const Skin& skin) {
   if (!skin.m_rawData.isEmpty()) {
+    if (qApp->styleSheet().simplified().isEmpty()) {
       qApp->setStyleSheet(skin.m_rawData);
     }
+    else {
+      qCriticalNN << LOGSEC_GUI
+                  << "Skipped setting of application style and skin because there is already some style set.";
+    }
+  }
 
   qApp->setStyle(qApp->settings()->value(GROUP(GUI), SETTING(GUI::Style)).toString());
 }
@@ -76,14 +82,17 @@ Skin SkinFactory::skinInfo(const QString& skin_name, bool* ok) const {
   base_skin_folders.append(customSkinBaseFolder());
 
   while (!base_skin_folders.isEmpty()) {
-    const QString skin_folder = base_skin_folders.takeAt(0) + QDir::separator() + skin_name + QDir::separator();
+    const QString skin_folder_no_sep = base_skin_folders.takeAt(0).replace(QDir::separator(),
+                                                                           QL1C('/')) + QL1C('/') + skin_name;
+    const QString skin_folder = skin_folder_no_sep + QDir::separator();
     const QString metadata_file = skin_folder + APP_SKIN_METADATA_FILE;
 
     if (QFile::exists(metadata_file)) {
       QFile skin_file(metadata_file);
       QDomDocument dokument;
 
-      if (!skin_file.open(QIODevice::Text | QIODevice::ReadOnly) || !dokument.setContent(&skin_file, true)) {
+      if (!skin_file.open(QIODevice::OpenModeFlag::Text | QIODevice::OpenModeFlag::ReadOnly) ||
+          !dokument.setContent(&skin_file, true)) {
         if (ok != nullptr) {
           *ok = false;
         }
@@ -132,22 +141,29 @@ Skin SkinFactory::skinInfo(const QString& skin_name, bool* ok) const {
       // Here we use "/" instead of QDir::separator() because CSS2.1 url field
       // accepts '/' as path elements separator.
       //
-      // "##" is placeholder for the actual path to skin file. This is needed for using
+      // USER_DATA_PLACEHOLDER is placeholder for the actual path to skin folder. This is needed for using
       // images within the QSS file.
-      // So if one uses "##/images/border.png" in QSS then it is
+      // So if one uses "%data%/images/border.png" in QSS then it is
       // replaced by fully absolute path and target file can
       // be safely loaded.
       skin.m_layoutMarkupWrapper = QString::fromUtf8(IOFactory::readFile(skin_folder + QL1S("html_wrapper.html")));
-      skin.m_layoutMarkupWrapper = skin.m_layoutMarkupWrapper.replace(QSL("##"), APP_SKIN_PATH + QL1S("/") + skin_name);
+      skin.m_layoutMarkupWrapper = skin.m_layoutMarkupWrapper.replace(QSL(USER_DATA_PLACEHOLDER),
+                                                                      skin_folder_no_sep);
       skin.m_enclosureImageMarkup = QString::fromUtf8(IOFactory::readFile(skin_folder + QL1S("html_enclosure_image.html")));
-      skin.m_enclosureImageMarkup = skin.m_enclosureImageMarkup.replace(QSL("##"), APP_SKIN_PATH + QL1S("/") + skin_name);
+      skin.m_enclosureImageMarkup = skin.m_enclosureImageMarkup.replace(QSL(USER_DATA_PLACEHOLDER),
+                                                                        skin_folder_no_sep);
       skin.m_layoutMarkup = QString::fromUtf8(IOFactory::readFile(skin_folder + QL1S("html_single_message.html")));
-      skin.m_layoutMarkup = skin.m_layoutMarkup.replace(QSL("##"), APP_SKIN_PATH + QL1S("/") + skin_name);
+      skin.m_layoutMarkup = skin.m_layoutMarkup.replace(QSL(USER_DATA_PLACEHOLDER),
+                                                        skin_folder_no_sep);
       skin.m_enclosureMarkup = QString::fromUtf8(IOFactory::readFile(skin_folder + QL1S("html_enclosure_every.html")));
-      skin.m_enclosureMarkup = skin.m_enclosureMarkup.replace(QSL("##"), APP_SKIN_PATH + QL1S("/") + skin_name);
+      skin.m_enclosureMarkup = skin.m_enclosureMarkup.replace(QSL(USER_DATA_PLACEHOLDER),
+                                                              skin_folder_no_sep);
       skin.m_rawData = QString::fromUtf8(IOFactory::readFile(skin_folder + QL1S("theme.css")));
-      skin.m_rawData = skin.m_rawData.replace(QSL("##"), APP_SKIN_PATH + QL1S("/") + skin_name);
+      skin.m_rawData = skin.m_rawData.replace(QSL(USER_DATA_PLACEHOLDER),
+                                              skin_folder_no_sep);
       skin.m_adblocked = QString::fromUtf8(IOFactory::readFile(skin_folder + QL1S("html_adblocked.html")));
+      skin.m_adblocked = skin.m_adblocked.replace(QSL(USER_DATA_PLACEHOLDER),
+                                                  skin_folder_no_sep);
 
       if (ok != nullptr) {
         *ok = !skin.m_author.isEmpty() && !skin.m_version.isEmpty() &&