Construct QString more efficiently

src/app/application.cpp

@@ -587,7 +587,7 @@ int Application::exec(const QStringList &params)
 #ifndef DISABLE_WEBUI
     Preferences *const pref = Preferences::instance();
     // Display some information to the user
-    const QString mesg = QString("\n******** %1 ********\n").arg(tr("Information"))
+    const QString mesg = QString::fromLatin1("\n******** %1 ********\n").arg(tr("Information"))
         + tr("To control qBittorrent, access the Web UI at %1")
             .arg(QString("http://localhost:") + QString::number(pref->getWebUiPort())) + '\n';
     printf("%s", qUtf8Printable(mesg));

src/app/cmdoptions.cpp

@@ -364,7 +364,7 @@ QStringList QBtCommandLineParameters::paramList() const
     // torrent paths or URLs.
 
     if (!savePath.isEmpty())
-        result.append(QString("@savePath=%1").arg(savePath));
+        result.append(QLatin1String("@savePath=") + savePath);
 
     if (addPaused == TriStateBool::True) {
         result.append(QLatin1String("@addPaused=1"));
@@ -377,7 +377,7 @@ QStringList QBtCommandLineParameters::paramList() const
         result.append(QLatin1String("@skipChecking"));
 
     if (!category.isEmpty())
-        result.append(QString("@category=%1").arg(category));
+        result.append(QLatin1String("@category=") + category);
 
     if (sequential)
         result.append(QLatin1String("@sequential"));

src/app/main.cpp

@@ -395,7 +395,7 @@ bool userAgreesWithLegalNotice()
     Q_ASSERT(!pref->getAcceptedLegal());
 
 #ifdef DISABLE_GUI
-    const QString eula = QString("\n*** %1 ***\n").arg(QObject::tr("Legal Notice"))
+    const QString eula = QString::fromLatin1("\n*** %1 ***\n").arg(QObject::tr("Legal Notice"))
         + QObject::tr("qBittorrent is a file sharing program. When you run a torrent, its data will be made available to others by means of upload. Any content you share is your sole responsibility.") + "\n\n"
         + QObject::tr("No further notices will be issued.") + "\n\n"
         + QObject::tr("Press %1 key to accept and continue...").arg("'y'") + '\n';

src/app/stacktrace_win.h

@@ -93,8 +93,8 @@ BOOL CALLBACK straceWin::EnumModulesCB(LPCSTR ModuleName, DWORD64 BaseOfDll, PVO
     EnumModulesContext* context = (EnumModulesContext*)UserContext;
     mod.SizeOfStruct = sizeof(IMAGEHLP_MODULE64);
     if(SymGetModuleInfo64(context->hProcess, BaseOfDll, &mod)) {
-        QString moduleBase = QString("0x%1").arg(BaseOfDll, 16, 16, QLatin1Char('0'));
-        QString line = QString("%1 %2 Image: %3")
+        QString moduleBase = QString::fromLatin1("0x%1").arg(BaseOfDll, 16, 16, QLatin1Char('0'));
+        QString line = QString::fromLatin1("%1 %2 Image: %3")
                        .arg(mod.ModuleName, -25)
                        .arg(moduleBase, -13)
                        .arg(mod.LoadedImageName);
@@ -102,7 +102,7 @@ BOOL CALLBACK straceWin::EnumModulesCB(LPCSTR ModuleName, DWORD64 BaseOfDll, PVO
 
         QString pdbName(mod.LoadedPdbName);
         if(!pdbName.isEmpty()) {
-            QString line2 = QString("%1 %2")
+            QString line2 = QString::fromLatin1("%1 %2")
                             .arg("", 35)
                             .arg(pdbName);
             context->stream << line2 << '\n';
@@ -165,7 +165,7 @@ QString straceWin::getSourcePathAndLineNumber(HANDLE hProcess, DWORD64 addr)
         }
 #endif
 #endif
-        return QString("%1 : %2").arg(path).arg(line.LineNumber);
+        return QString::fromLatin1("%1 : %2").arg(path).arg(line.LineNumber);
     }
 
     return QString();
@@ -296,7 +296,7 @@ const QString straceWin::getBacktrace()
                 sourceFile = getSourcePathAndLineNumber(hProcess, ihsf.InstructionOffset - 1);
             }
             else {
-                funcName = QString("0x%1").arg(ihsf.InstructionOffset, 8, 16, QLatin1Char('0'));
+                funcName = QString::fromLatin1("0x%1").arg(ihsf.InstructionOffset, 8, 16, QLatin1Char('0'));
             }
             SymSetContext(hProcess, &ihsf, NULL);
 #ifndef __MINGW32__
@@ -304,7 +304,7 @@ const QString straceWin::getBacktrace()
             SymEnumSymbols(hProcess, 0, NULL, EnumSymbolsCB, (PVOID)&params);
 #endif
 
-            QString insOffset = QString("0x%1").arg(ihsf.InstructionOffset, 16, 16, QLatin1Char('0'));
+            QString insOffset = QString::fromLatin1("0x%1").arg(ihsf.InstructionOffset, 16, 16, QLatin1Char('0'));
             QString formatLine = "#%1 %2 %3 %4";
 #ifndef __MINGW32__
             formatLine += "(%5)";
@@ -318,7 +318,7 @@ const QString straceWin::getBacktrace()
                                 .arg(params.join(", "));
 
             if (!sourceFile.isEmpty())
-                debugLine += QString("[ %1 ]").arg(sourceFile);
+                debugLine += QString::fromLatin1("[ %1 ]").arg(sourceFile);
 #else
                                 ;
 #endif

src/base/bittorrent/session.cpp

@@ -1810,7 +1810,7 @@ bool Session::deleteTorrent(const InfoHash &hash, const DeleteOption deleteOptio
     // Remove it from torrent resume directory
     const QDir resumeDataDir(m_resumeFolderPath);
     QStringList filters;
-    filters << QString("%1.*").arg(torrent->hash());
+    filters << QString::fromLatin1("%1.*").arg(torrent->hash());
     const QStringList files = resumeDataDir.entryList(filters, QDir::Files, QDir::Unsorted);
     for (const QString &file : files)
         Utils::Fs::forceRemove(resumeDataDir.absoluteFilePath(file));
@@ -2457,8 +2457,8 @@ void Session::exportTorrentFile(TorrentHandle *const torrent, TorrentExportFolde
              ((folder == TorrentExportFolder::Finished) && !finishedTorrentExportDirectory().isEmpty()));
 
     const QString validName = Utils::Fs::toValidFileSystemName(torrent->name());
-    const QString torrentFilename = QString("%1.torrent").arg(torrent->hash());
-    QString torrentExportFilename = QString("%1.torrent").arg(validName);
+    const QString torrentFilename = QString::fromLatin1("%1.torrent").arg(torrent->hash());
+    QString torrentExportFilename = QString::fromLatin1("%1.torrent").arg(validName);
     const QString torrentPath = QDir(m_resumeFolderPath).absoluteFilePath(torrentFilename);
     const QDir exportPath(folder == TorrentExportFolder::Regular ? torrentExportDirectory() : finishedTorrentExportDirectory());
     if (exportPath.exists() || exportPath.mkpath(exportPath.absolutePath())) {
@@ -2466,7 +2466,7 @@ void Session::exportTorrentFile(TorrentHandle *const torrent, TorrentExportFolde
         int counter = 0;
         while (QFile::exists(newTorrentPath) && !Utils::Fs::sameFiles(torrentPath, newTorrentPath)) {
             // Append number to torrent name to make it unique
-            torrentExportFilename = QString("%1 %2.torrent").arg(validName).arg(++counter);
+            torrentExportFilename = QString::fromLatin1("%1 %2.torrent").arg(validName).arg(++counter);
             newTorrentPath = exportPath.absoluteFilePath(torrentExportFilename);
         }
 
@@ -3923,7 +3923,7 @@ void Session::handleTorrentResumeDataReady(TorrentHandle *const torrent, const l
     out.reserve(1024 * 1024);  // most fastresume file sizes are under 1 MB
     lt::bencode(std::back_inserter(out), data);
 
-    const QString filename = QString("%1.fastresume").arg(torrent->hash());
+    const QString filename = QString::fromLatin1("%1.fastresume").arg(torrent->hash());
 #if (QT_VERSION >= QT_VERSION_CHECK(5, 10, 0))
     QMetaObject::invokeMethod(m_resumeDataSavingManager
         , [this, filename, out]() { m_resumeDataSavingManager->save(filename, out); });
@@ -4160,7 +4160,7 @@ void Session::startUpTorrents()
     int resumedTorrentsCount = 0;
     const auto startupTorrent = [this, &resumeDataDir, &resumedTorrentsCount](const TorrentResumeData &params)
     {
-        const QString filePath = resumeDataDir.filePath(QString("%1.torrent").arg(params.hash));
+        const QString filePath = resumeDataDir.filePath(QString::fromLatin1("%1.torrent").arg(params.hash));
         qDebug() << "Starting up torrent" << params.hash << "...";
         if (!addTorrent_impl(params.addTorrentData, params.magnetUri, TorrentInfo::loadFromFile(filePath), params.data))
             LogMsg(tr("Unable to resume torrent '%1'.", "e.g: Unable to resume torrent 'hash'.")

src/base/http/responsegenerator.cpp

@@ -54,7 +54,7 @@ QByteArray Http::toByteArray(Response response)
 
     // Header Fields
     for (auto i = response.headers.constBegin(); i != response.headers.constEnd(); ++i)
-        buf += QString("%1: %2").arg(i.key(), i.value()).toLatin1().append(CRLF);
+        buf += QString::fromLatin1("%1: %2").arg(i.key(), i.value()).toLatin1().append(CRLF);
 
     // the first empty line
     buf += CRLF;

src/base/net/geoipmanager.cpp

@@ -88,7 +88,7 @@ void GeoIPManager::loadDatabase()
     m_geoIPDatabase = nullptr;
 
     const QString filepath = Utils::Fs::expandPathAbs(
-        QString("%1%2/%3").arg(specialFolderLocation(SpecialFolder::Data), GEODB_FOLDER, GEODB_FILENAME));
+        QString::fromLatin1("%1%2/%3").arg(specialFolderLocation(SpecialFolder::Data), GEODB_FOLDER, GEODB_FILENAME));
 
     QString error;
     m_geoIPDatabase = GeoIPDatabase::load(filepath, error);
@@ -442,7 +442,7 @@ void GeoIPManager::downloadFinished(const DownloadResult &result)
                         specialFolderLocation(SpecialFolder::Data) + GEODB_FOLDER);
             if (!QDir(targetPath).exists())
                 QDir().mkpath(targetPath);
-            QFile targetFile(QString("%1/%2").arg(targetPath, GEODB_FILENAME));
+            QFile targetFile(QString::fromLatin1("%1/%2").arg(targetPath, GEODB_FILENAME));
             if (!targetFile.open(QFile::WriteOnly) || (targetFile.write(data) == -1))
                 LogMsg(tr("Couldn't save downloaded IP geolocation database file."), Log::WARNING);
             else

src/base/net/proxyconfigurationmanager.cpp

@@ -139,17 +139,17 @@ void ProxyConfigurationManager::configureProxy()
     if (!m_isProxyOnlyForTorrents) {
         switch (m_config.type) {
         case ProxyType::HTTP_PW:
-            proxyStrHTTP = QString("http://%1:%2@%3:%4").arg(m_config.username
+            proxyStrHTTP = QString::fromLatin1("http://%1:%2@%3:%4").arg(m_config.username
                 , m_config.password, m_config.ip, QString::number(m_config.port));
             break;
         case ProxyType::HTTP:
-            proxyStrHTTP = QString("http://%1:%2").arg(m_config.ip, QString::number(m_config.port));
+            proxyStrHTTP = QString::fromLatin1("http://%1:%2").arg(m_config.ip, QString::number(m_config.port));
             break;
         case ProxyType::SOCKS5:
-            proxyStrSOCK = QString("%1:%2").arg(m_config.ip, QString::number(m_config.port));
+            proxyStrSOCK = QString::fromLatin1("%1:%2").arg(m_config.ip, QString::number(m_config.port));
             break;
         case ProxyType::SOCKS5_PW:
-            proxyStrSOCK = QString("%1:%2@%3:%4").arg(m_config.username
+            proxyStrSOCK = QString::fromLatin1("%1:%2@%3:%4").arg(m_config.username
                 , m_config.password, m_config.ip, QString::number(m_config.port));
             break;
         default:

src/base/rss/rss_autodownloader.cpp

@@ -100,7 +100,7 @@ QPointer<AutoDownloader> AutoDownloader::m_instance = nullptr;
 
 QString computeSmartFilterRegex(const QStringList &filters)
 {
-    return QString("(?:_|\\b)(?:%1)(?:_|\\b)").arg(filters.join(QString(")|(?:")));
+    return QString::fromLatin1("(?:_|\\b)(?:%1)(?:_|\\b)").arg(filters.join(QString(")|(?:")));
 }
 
 AutoDownloader::AutoDownloader()

src/base/rss/rss_autodownloadrule.cpp

@@ -323,7 +323,7 @@ bool AutoDownloadRule::matchesEpisodeFilterExpression(const QString &articleTitl
             }
         }
         else { // Single number
-            const QString expStr {QString("\\b(?:s0?%1[ -_\\.]?e0?%2|%1x0?%2)(?:\\D|\\b)").arg(season, episode)};
+            const QString expStr {QString::fromLatin1("\\b(?:s0?%1[ -_\\.]?e0?%2|%1x0?%2)(?:\\D|\\b)").arg(season, episode)};
             if (cachedRegex(expStr).match(articleTitle).hasMatch())
                 return true;
         }
@@ -354,7 +354,7 @@ bool AutoDownloadRule::matchesSmartEpisodeFilter(const QString &articleTitle) co
         if (!isRepack && !isProper)
             return false;
 
-        const QString fullEpisodeStr = QString("%1%2%3").arg(episodeStr,
+        const QString fullEpisodeStr = QString::fromLatin1("%1%2%3").arg(episodeStr,
                                                              isRepack ? "-REPACK" : "",
                                                              isProper ? "-PROPER" : "");
         const bool previouslyMatchedFull = m_dataPtr->previouslyMatchedEpisodes.contains(fullEpisodeStr);
@@ -366,8 +366,8 @@ bool AutoDownloadRule::matchesSmartEpisodeFilter(const QString &articleTitle) co
         // If this is a REPACK and PROPER download, add the individual entries to the list
         // so we don't download those
         if (isRepack && isProper) {
-            m_dataPtr->lastComputedEpisodes.append(QString("%1-REPACK").arg(episodeStr));
-            m_dataPtr->lastComputedEpisodes.append(QString("%1-PROPER").arg(episodeStr));
+            m_dataPtr->lastComputedEpisodes.append(episodeStr + QLatin1String("-REPACK"));
+            m_dataPtr->lastComputedEpisodes.append(episodeStr + QLatin1String("-PROPER"));
         }
     }
 

src/base/rss/rss_feed.cpp

@@ -400,7 +400,7 @@ void Feed::downloadIcon()
     // Download the RSS Feed icon
     // XXX: This works for most sites but it is not perfect
     const QUrl url(m_url);
-    const auto iconUrl = QString("%1://%2/favicon.ico").arg(url.scheme(), url.host());
+    const auto iconUrl = QString::fromLatin1("%1://%2/favicon.ico").arg(url.scheme(), url.host());
     Net::DownloadManager::instance()->download(
             Net::DownloadRequest(iconUrl).saveToFile(true)
                 , this, &Feed::handleIconDownloadFinished);

src/base/rss/rss_session.cpp

@@ -330,7 +330,7 @@ void Session::loadFolder(const QJsonObject &jsonObj, Folder *folder)
         }
         else {
             LogMsg(tr("Couldn't load RSS Item '%1'. Invalid data format.")
-                   .arg(QString("%1\\%2").arg(folder->path(), key)), Log::WARNING);
+                   .arg(QString::fromLatin1("%1\\%2").arg(folder->path(), key)), Log::WARNING);
         }
     }
 

src/base/search/searchpluginmanager.cpp

@@ -185,7 +185,7 @@ void SearchPluginManager::enablePlugin(const QString &name, const bool enabled)
 // Updates shipped plugin
 void SearchPluginManager::updatePlugin(const QString &name)
 {
-    installPlugin(QString("%1%2.py").arg(m_updateUrl, name));
+    installPlugin(QString::fromLatin1("%1%2.py").arg(m_updateUrl, name));
 }
 
 // Install or update plugin from file or url
@@ -283,12 +283,12 @@ bool SearchPluginManager::uninstallPlugin(const QString &name)
 void SearchPluginManager::updateIconPath(PluginInfo *const plugin)
 {
     if (!plugin) return;
-    QString iconPath = QString("%1/%2.png").arg(pluginsLocation(), plugin->name);
+    QString iconPath = QString::fromLatin1("%1/%2.png").arg(pluginsLocation(), plugin->name);
     if (QFile::exists(iconPath)) {
         plugin->iconPath = iconPath;
     }
     else {
-        iconPath = QString("%1/%2.ico").arg(pluginsLocation(), plugin->name);
+        iconPath = QString::fromLatin1("%1/%2.ico").arg(pluginsLocation(), plugin->name);
         if (QFile::exists(iconPath))
             plugin->iconPath = iconPath;
     }
@@ -338,7 +338,7 @@ QString SearchPluginManager::pluginFullName(const QString &pluginName)
 
 QString SearchPluginManager::pluginsLocation()
 {
-    return QString("%1/engines").arg(engineLocation());
+    return QString::fromLatin1("%1/engines").arg(engineLocation());
 }
 
 QString SearchPluginManager::engineLocation()
@@ -526,7 +526,7 @@ bool SearchPluginManager::isUpdateNeeded(const QString &pluginName, const Plugin
 
 QString SearchPluginManager::pluginPath(const QString &name)
 {
-    return QString("%1/%2.py").arg(pluginsLocation(), name);
+    return QString::fromLatin1("%1/%2.py").arg(pluginsLocation(), name);
 }
 
 PluginVersion SearchPluginManager::getPluginVersion(const QString &filePath)

src/gui/aboutdialog.cpp

@@ -43,7 +43,7 @@ AboutDialog::AboutDialog(QWidget *parent)
     setAttribute(Qt::WA_DeleteOnClose);
 
     // Title
-    m_ui->labelName->setText(QString("<b><h2>qBittorrent " QBT_VERSION " (%1-bit)</h2></b>").arg(QT_POINTER_SIZE * 8));
+    m_ui->labelName->setText(QString::fromLatin1("<b><h2>qBittorrent " QBT_VERSION " (%1-bit)</h2></b>").arg(QT_POINTER_SIZE * 8));
 
     m_ui->logo->setPixmap(Utils::Gui::scaledPixmapSvg(":/icons/skin/qbittorrent-tray.svg", this, 32));
 

src/gui/advancedsettings.cpp

@@ -333,7 +333,7 @@ void AdvancedSettings::loadAdvancedSettings()
                  , tr("Open documentation"))
         , this);
     labelQbtLink->setOpenExternalLinks(true);
-    addRow(QBITTORRENT_HEADER, QString("<b>%1</b>").arg(tr("qBittorrent Section")), labelQbtLink);
+    addRow(QBITTORRENT_HEADER, QString::fromLatin1("<b>%1</b>").arg(tr("qBittorrent Section")), labelQbtLink);
     static_cast<QLabel *>(cellWidget(QBITTORRENT_HEADER, PROPERTY))->setAlignment(Qt::AlignCenter | Qt::AlignVCenter);
 
     auto *labelLibtorrentLink = new QLabel(
@@ -341,7 +341,7 @@ void AdvancedSettings::loadAdvancedSettings()
                  , tr("Open documentation"))
         , this);
     labelLibtorrentLink->setOpenExternalLinks(true);
-    addRow(LIBTORRENT_HEADER, QString("<b>%1</b>").arg(tr("libtorrent Section")), labelLibtorrentLink);
+    addRow(LIBTORRENT_HEADER, QString::fromLatin1("<b>%1</b>").arg(tr("libtorrent Section")), labelLibtorrentLink);
     static_cast<QLabel *>(cellWidget(LIBTORRENT_HEADER, PROPERTY))->setAlignment(Qt::AlignCenter | Qt::AlignVCenter);
 
 #if defined(Q_OS_WIN)

src/gui/categoryfiltermodel.cpp

@@ -75,7 +75,7 @@ public:
         if (!m_parent || m_parent->name().isEmpty())
             return m_name;
 
-        return QString("%1/%2").arg(m_parent->fullName(), m_name);
+        return QString::fromLatin1("%1/%2").arg(m_parent->fullName(), m_name);
     }
 
     CategoryModelItem *parent() const

src/gui/lineedit.cpp

@@ -27,7 +27,7 @@ LineEdit::LineEdit(QWidget *parent)
     m_searchButton->setStyleSheet("QToolButton {border: none; padding: 2px;}");
 
     // padding between text and widget borders
-    setStyleSheet(QString("QLineEdit {padding-left: %1px;}").arg(m_searchButton->sizeHint().width()));
+    setStyleSheet(QString::fromLatin1("QLineEdit {padding-left: %1px;}").arg(m_searchButton->sizeHint().width()));
 
     setClearButtonEnabled(true);
 

src/gui/mainwindow.cpp

@@ -1539,7 +1539,7 @@ void MainWindow::reloadSessionStats()
                  , tr("UP speed: %1", "e.g: Upload speed: 10 KiB/s").arg(Utils::Misc::friendlyUnit(status.payloadUploadRate, true)));
 #else
         // OSes such as Windows do not support html here
-        const QString toolTip = QString("%1\n%2").arg(
+        const QString toolTip = QString::fromLatin1("%1\n%2").arg(
             tr("DL speed: %1", "e.g: Download speed: 10 KiB/s").arg(Utils::Misc::friendlyUnit(status.payloadDownloadRate, true))
             , tr("UP speed: %1", "e.g: Upload speed: 10 KiB/s").arg(Utils::Misc::friendlyUnit(status.payloadUploadRate, true)));
 #endif // Q_OS_UNIX
@@ -1818,7 +1818,7 @@ void MainWindow::handleUpdateCheckFinished(bool updateAvailable, QString newVers
         answer = QMessageBox::question(this, tr("qBittorrent Update Available")
             , tr("A new version is available.") + "<br/>"
                 + tr("Do you want to download %1?").arg(newVersion) + "<br/><br/>"
-                + QString("<a href=\"https://www.qbittorrent.org/news.php\">%1</a>").arg(tr("Open changelog..."))
+                + QString::fromLatin1("<a href=\"https://www.qbittorrent.org/news.php\">%1</a>").arg(tr("Open changelog..."))
             , QMessageBox::Yes | QMessageBox::No, QMessageBox::Yes);
         if (answer == QMessageBox::Yes) {
             // The user want to update, let's download the update

src/gui/optionsdialog.cpp

@@ -1559,7 +1559,7 @@ void OptionsDialog::on_addScanFolderButton_clicked()
         }
 
         if (!error.isEmpty())
-            QMessageBox::critical(this, tr("Adding entry failed"), QString("%1\n%2").arg(error, dir));
+            QMessageBox::critical(this, tr("Adding entry failed"), QString::fromLatin1("%1\n%2").arg(error, dir));
     }
 }
 

src/gui/rss/automatedrssdownloader.cpp

@@ -59,8 +59,8 @@ const QString EXT_LEGACY {QStringLiteral(".rssrules")};
 
 AutomatedRssDownloader::AutomatedRssDownloader(QWidget *parent)
     : QDialog(parent)
-    , m_formatFilterJSON(QString("%1 (*%2)").arg(tr("Rules"), EXT_JSON))
-    , m_formatFilterLegacy(QString("%1 (*%2)").arg(tr("Rules (legacy)"), EXT_LEGACY))
+    , m_formatFilterJSON(QString::fromLatin1("%1 (*%2)").arg(tr("Rules"), EXT_JSON))
+    , m_formatFilterLegacy(QString::fromLatin1("%1 (*%2)").arg(tr("Rules (legacy)"), EXT_LEGACY))
     , m_ui(new Ui::AutomatedRssDownloader)
     , m_currentRuleItem(nullptr)
 {
@@ -413,7 +413,7 @@ void AutomatedRssDownloader::on_exportBtn_clicked()
     QString selectedFilter {m_formatFilterJSON};
     QString path = QFileDialog::getSaveFileName(
                 this, tr("Export RSS rules"), QDir::homePath()
-                , QString("%1;;%2").arg(m_formatFilterJSON, m_formatFilterLegacy), &selectedFilter);
+                , QString::fromLatin1("%1;;%2").arg(m_formatFilterJSON, m_formatFilterLegacy), &selectedFilter);
     if (path.isEmpty()) return;
 
     const RSS::AutoDownloader::RulesFileFormat format {
@@ -445,7 +445,7 @@ void AutomatedRssDownloader::on_importBtn_clicked()
     QString selectedFilter {m_formatFilterJSON};
     QString path = QFileDialog::getOpenFileName(
                 this, tr("Import RSS rules"), QDir::homePath()
-                , QString("%1;;%2").arg(m_formatFilterJSON, m_formatFilterLegacy), &selectedFilter);
+                , QString::fromLatin1("%1;;%2").arg(m_formatFilterJSON, m_formatFilterLegacy), &selectedFilter);
     if (path.isEmpty() || !QFile::exists(path))
         return;
 

src/gui/rss/feedlistwidget.cpp

@@ -113,7 +113,7 @@ void FeedListWidget::handleItemUnreadCountChanged(RSS::Item *rssItem)
     else {
         QTreeWidgetItem *item = mapRSSItem(rssItem);
         Q_ASSERT(item);
-        item->setData(0, Qt::DisplayRole, QString("%1  (%2)").arg(rssItem->name()).arg(rssItem->unreadCount()));
+        item->setData(0, Qt::DisplayRole, QString::fromLatin1("%1  (%2)").arg(rssItem->name(), QString::number(rssItem->unreadCount())));
     }
 }
 
@@ -122,7 +122,7 @@ void FeedListWidget::handleItemPathChanged(RSS::Item *rssItem)
     QTreeWidgetItem *item = mapRSSItem(rssItem);
     Q_ASSERT(item);
 
-    item->setData(0, Qt::DisplayRole, QString("%1  (%2)").arg(rssItem->name()).arg(rssItem->unreadCount()));
+    item->setData(0, Qt::DisplayRole, QString::fromLatin1("%1  (%2)").arg(rssItem->name(), QString::number(rssItem->unreadCount())));
 
     RSS::Item *parentRssItem = RSS::Session::instance()->itemByPath(RSS::Item::parentPath(rssItem->path()));
     QTreeWidgetItem *parentItem = mapRSSItem(parentRssItem);
@@ -228,7 +228,7 @@ void FeedListWidget::dropEvent(QDropEvent *event)
 QTreeWidgetItem *FeedListWidget::createItem(RSS::Item *rssItem, QTreeWidgetItem *parentItem)
 {
     auto *item = new QTreeWidgetItem;
-    item->setData(0, Qt::DisplayRole, QString("%1  (%2)").arg(rssItem->name()).arg(rssItem->unreadCount()));
+    item->setData(0, Qt::DisplayRole, QString::fromLatin1("%1  (%2)").arg(rssItem->name(), QString::number(rssItem->unreadCount())));
     item->setData(0, Qt::UserRole, reinterpret_cast<quintptr>(rssItem));
     m_rssToTreeItemMapping[rssItem] = item;
 

src/gui/statsdialog.cpp

@@ -80,20 +80,19 @@ void StatsDialog::update()
                 : "-");
     // Cache hits
     qreal readRatio = cs.readRatio;
-    m_ui->labelCacheHits->setText(QString("%1%").arg(
-        readRatio > 0
+    m_ui->labelCacheHits->setText(QString::fromLatin1("%1%").arg((readRatio > 0)
         ? Utils::String::fromDouble(100 * readRatio, 2)
-        : "0"));
+        : QLatin1String("0")));
     // Buffers size
     m_ui->labelTotalBuf->setText(Utils::Misc::friendlyUnit(cs.totalUsedBuffers * 16 * 1024));
     // Disk overload (100%) equivalent
     // From lt manual: disk_write_queue and disk_read_queue are the number of peers currently waiting on a disk write or disk read
     // to complete before it receives or sends any more data on the socket. It's a metric of how disk bound you are.
 
-    m_ui->labelWriteStarve->setText(QString("%1%").arg(((ss.diskWriteQueue > 0) && (ss.peersCount > 0))
+    m_ui->labelWriteStarve->setText(QString::fromLatin1("%1%").arg(((ss.diskWriteQueue > 0) && (ss.peersCount > 0))
         ? Utils::String::fromDouble((100. * ss.diskWriteQueue / ss.peersCount), 2)
         : QLatin1String("0")));
-    m_ui->labelReadStarve->setText(QString("%1%").arg(((ss.diskReadQueue > 0) && (ss.peersCount > 0))
+    m_ui->labelReadStarve->setText(QString::fromLatin1("%1%").arg(((ss.diskReadQueue > 0) && (ss.peersCount > 0))
         ? Utils::String::fromDouble((100. * ss.diskReadQueue / ss.peersCount), 2)
         : QLatin1String("0")));
 

src/gui/tagfiltermodel.cpp

@@ -319,7 +319,7 @@ QVector<TagModelItem *> TagFilterModel::findItems(const QSet<QString> &tags)
         if (item)
             items.push_back(item);
         else
-            qWarning() << QString("Requested tag '%1' missing from the model.").arg(tag);
+            qWarning() << QString::fromLatin1("Requested tag '%1' missing from the model.").arg(tag);
     }
     return items;
 }

src/gui/torrentcreatordialog.cpp

@@ -215,7 +215,7 @@ void TorrentCreatorDialog::handleCreationSuccess(const QString &path, const QStr
         BitTorrent::Session::instance()->addTorrent(info, params);
     }
     QMessageBox::information(this, tr("Torrent creator")
-        , QString("%1\n%2").arg(tr("Torrent created:"), Utils::Fs::toNativePath(path)));
+        , QString::fromLatin1("%1\n%2").arg(tr("Torrent created:"), Utils::Fs::toNativePath(path)));
     setInteractionEnabled(true);
 }
 

src/gui/transferlistfilterswidget.cpp

@@ -327,7 +327,7 @@ void TrackerFiltersList::addItem(const QString &tracker, const QString &hash)
         trackerItem->setData(Qt::DecorationRole, UIThemeManager::instance()->getIcon("network-server"));
 
         const QString scheme = getScheme(tracker);
-        downloadFavicon(QString("%1://%2/favicon.ico").arg((scheme.startsWith("http") ? scheme : "http"), host));
+        downloadFavicon(QString::fromLatin1("%1://%2/favicon.ico").arg((scheme.startsWith("http") ? scheme : "http"), host));
     }
     if (!trackerItem) return;
 
@@ -340,7 +340,7 @@ void TrackerFiltersList::addItem(const QString &tracker, const QString &hash)
         return;
     }
 
-    trackerItem->setText(QString("%1 (%2)").arg(host).arg(tmp.size()));
+    trackerItem->setText(QString::fromLatin1("%1 (%2)").arg(host, QString::number(tmp.size())));
     if (exists) {
         if (currentRow() == rowFromTracker(host))
             applyFilter(currentRow());
@@ -384,7 +384,7 @@ void TrackerFiltersList::removeItem(const QString &tracker, const QString &hash)
             return;
         }
         if (trackerItem)
-            trackerItem->setText(QString("%1 (%2)").arg(host).arg(tmp.size()));
+            trackerItem->setText(QString::fromLatin1("%1 (%2)").arg(host, QString::number(tmp.size())));
     }
     else {
         row = 1;