QtHelp: More _L1

Task-number: QTBUG-122025
Change-Id: Icbdb003e9bd1b05bfb9d92002aab2aa5cc1aa0f7
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>

25 files changed, 292 insertions, 296 deletions

diff --git a/src/assistant/help/qcompressedhelpinfo.h b/src/assistant/help/qcompressedhelpinfo.h
index bae87aa83..a68c03c11 100644
--- a/src/assistant/help/qcompressedhelpinfo.h
+++ b/src/assistant/help/qcompressedhelpinfo.h
@@ -40,4 +40,4 @@ private:
 
 QT_END_NAMESPACE
 
-#endif // QHELPCOLLECTIONDETAILS_H
+#endif // QCOMPRESSEDHELPINFO_H
diff --git a/src/assistant/help/qhelp_global.cpp b/src/assistant/help/qhelp_global.cpp
index 3eb964766..bd4c85ff4 100644
--- a/src/assistant/help/qhelp_global.cpp
+++ b/src/assistant/help/qhelp_global.cpp
@@ -8,6 +8,10 @@
 #include <QtCore/qmutex.h>
 #include <QtGui/qtextdocument.h>
 
+QT_BEGIN_NAMESPACE
+
+using namespace Qt::StringLiterals;
+
 QString QHelpGlobal::uniquifyConnectionName(const QString &name, void *pointer)
 {
     static QMutex mutex;
@@ -20,11 +24,11 @@ QString QHelpGlobal::documentTitle(const QString &content)
 {
     QString title = QCoreApplication::translate("QHelp", "Untitled");
     if (!content.isEmpty()) {
-        const int start = content.indexOf(QLatin1String("<title>"), 0, Qt::CaseInsensitive) + 7;
-        const int end = content.indexOf(QLatin1String("</title>"), 0, Qt::CaseInsensitive);
+        const int start = content.indexOf("<title>"_L1, 0, Qt::CaseInsensitive) + 7;
+        const int end = content.indexOf("</title>"_L1, 0, Qt::CaseInsensitive);
         if ((end - start) > 0) {
             title = content.mid(start, end - start);
-            if (Qt::mightBeRichText(title) || title.contains(QLatin1Char('&'))) {
+            if (Qt::mightBeRichText(title) || title.contains(u'&')) {
                 QTextDocument doc;
                 doc.setHtml(title);
                 title = doc.toPlainText();
@@ -33,3 +37,5 @@ QString QHelpGlobal::documentTitle(const QString &content)
     }
     return title;
 }
+
+QT_END_NAMESPACE
diff --git a/src/assistant/help/qhelpcollectionhandler.cpp b/src/assistant/help/qhelpcollectionhandler.cpp
index cc270f1b8..a9f17131f 100644
--- a/src/assistant/help/qhelpcollectionhandler.cpp
+++ b/src/assistant/help/qhelpcollectionhandler.cpp
@@ -225,7 +225,7 @@ QString QHelpCollectionHandler::absoluteDocPath(const QString &fileName) const
     const QFileInfo fi(collectionFile());
     return QDir::isAbsolutePath(fileName)
             ? fileName
-            : QFileInfo(fi.absolutePath() + QLatin1Char('/') + fileName).absoluteFilePath();
+            : QFileInfo(fi.absolutePath() + u'/' + fileName).absoluteFilePath();
 }
 
 bool QHelpCollectionHandler::isTimeStampCorrect(const TimeStamp &timeStamp) const
@@ -336,7 +336,7 @@ bool QHelpCollectionHandler::copyCollectionFile(const QString &fileName)
         copyQuery.bindValue(0, m_query->value(0).toString());
         QString oldFilePath = m_query->value(1).toString();
         if (!QDir::isAbsolutePath(oldFilePath))
-            oldFilePath = oldBaseDir + QLatin1Char('/') + oldFilePath;
+            oldFilePath = oldBaseDir + u'/' + oldFilePath;
         copyQuery.bindValue(1, newColFi.absoluteDir().relativeFilePath(oldFilePath));
         copyQuery.exec();
     }
@@ -923,16 +923,16 @@ static QHelpCollectionHandler::FileInfo extractFileInfo(const QUrl &url)
 {
     QHelpCollectionHandler::FileInfo fileInfo;
 
-    if (!url.isValid() || url.toString().count(QLatin1Char('/')) < 4
+    if (!url.isValid() || url.toString().count(u'/') < 4
         || url.scheme() != "qthelp"_L1) {
         return fileInfo;
     }
 
     fileInfo.namespaceName = url.authority();
     fileInfo.fileName = url.path();
-    if (fileInfo.fileName.startsWith(QLatin1Char('/')))
+    if (fileInfo.fileName.startsWith(u'/'))
         fileInfo.fileName = fileInfo.fileName.mid(1);
-    fileInfo.folderName = fileInfo.fileName.mid(0, fileInfo.fileName.indexOf(QLatin1Char('/'), 1));
+    fileInfo.folderName = fileInfo.fileName.mid(0, fileInfo.fileName.indexOf(u'/', 1));
     fileInfo.fileName.remove(0, fileInfo.folderName.size() + 1);
 
     return fileInfo;
@@ -1232,11 +1232,8 @@ QStringList QHelpCollectionHandler::files(const QString &namespaceName,
         return {};
 
     QStringList fileNames;
-    while (m_query->next()) {
-        fileNames.append(m_query->value(0).toString()
-                         + QLatin1Char('/')
-                         + m_query->value(1).toString());
-    }
+    while (m_query->next())
+        fileNames.append(m_query->value(0).toString() + u'/' + m_query->value(1).toString());
     return fileNames;
 }
 
@@ -1278,11 +1275,8 @@ QStringList QHelpCollectionHandler::files(const QString &namespaceName,
         return{};
 
     QStringList fileNames;
-    while (m_query->next()) {
-        fileNames.append(m_query->value(0).toString()
-                         + QLatin1Char('/')
-                         + m_query->value(1).toString());
-    }
+    while (m_query->next())
+        fileNames.append(m_query->value(0).toString() + u'/' + m_query->value(1).toString());
     return fileNames;
 }
 
@@ -2218,7 +2212,7 @@ QUrl QHelpCollectionHandler::buildQUrl(const QString &ns, const QString &folder,
     QUrl url;
     url.setScheme("qthelp"_L1);
     url.setAuthority(ns);
-    url.setPath(QLatin1Char('/') + folder + QLatin1Char('/') + relFileName);
+    url.setPath(u'/' + folder + u'/' + relFileName);
     url.setFragment(anchor);
     return url;
 }
diff --git a/src/assistant/help/qhelpcollectionhandler_p.h b/src/assistant/help/qhelpcollectionhandler_p.h
index 625835daf..4fe9e7a2c 100644
--- a/src/assistant/help/qhelpcollectionhandler_p.h
+++ b/src/assistant/help/qhelpcollectionhandler_p.h
@@ -197,4 +197,4 @@ private:
 
 QT_END_NAMESPACE
 
-#endif  //QHELPCOLLECTIONHANDLER_H
+#endif // QHELPCOLLECTIONHANDLER_H
diff --git a/src/assistant/help/qhelpcontentwidget.cpp b/src/assistant/help/qhelpcontentwidget.cpp
index d692776b6..482414cc1 100644
--- a/src/assistant/help/qhelpcontentwidget.cpp
+++ b/src/assistant/help/qhelpcontentwidget.cpp
@@ -13,6 +13,8 @@
 
 QT_BEGIN_NAMESPACE
 
+using namespace Qt::StringLiterals;
+
 class QHelpContentModelPrivate
 {
 #if QT_CONFIG(future)
@@ -259,7 +261,7 @@ QHelpContentWidget::QHelpContentWidget()
 QModelIndex QHelpContentWidget::indexOf(const QUrl &link)
 {
     QHelpContentModel *contentModel = qobject_cast<QHelpContentModel*>(model());
-    if (!contentModel || link.scheme() != QLatin1String("qthelp"))
+    if (!contentModel || link.scheme() != "qthelp"_L1)
         return {};
 
     m_syncIndex = {};
diff --git a/src/assistant/help/qhelpcontentwidget.h b/src/assistant/help/qhelpcontentwidget.h
index 9a7e7db41..cf9668835 100644
--- a/src/assistant/help/qhelpcontentwidget.h
+++ b/src/assistant/help/qhelpcontentwidget.h
@@ -72,5 +72,4 @@ private:
 
 QT_END_NAMESPACE
 
-#endif
-
+#endif // QHELPCONTENTWIDGET_H
diff --git a/src/assistant/help/qhelpdbreader.cpp b/src/assistant/help/qhelpdbreader.cpp
index 5a8a3a704..cfe1b6839 100644
--- a/src/assistant/help/qhelpdbreader.cpp
+++ b/src/assistant/help/qhelpdbreader.cpp
@@ -13,9 +13,11 @@
 
 QT_BEGIN_NAMESPACE
 
+using namespace Qt::StringLiterals;
+
 QHelpDBReader::QHelpDBReader(const QString &dbName)
     : m_dbName(dbName)
-    , m_uniqueId(QHelpGlobal::uniquifyConnectionName(QLatin1String("QHelpDBReader"), this))
+    , m_uniqueId(QHelpGlobal::uniquifyConnectionName("QHelpDBReader"_L1, this))
 {}
 
 QHelpDBReader::QHelpDBReader(const QString &dbName, const QString &uniqueId, QObject *parent)
@@ -50,8 +52,8 @@ bool QHelpDBReader::init()
 
 bool QHelpDBReader::initDB()
 {
-    QSqlDatabase db = QSqlDatabase::addDatabase(QLatin1String("QSQLITE"), m_uniqueId);
-    db.setConnectOptions(QLatin1String("QSQLITE_OPEN_READONLY"));
+    QSqlDatabase db = QSqlDatabase::addDatabase("QSQLITE"_L1, m_uniqueId);
+    db.setConnectOptions("QSQLITE_OPEN_READONLY"_L1);
     db.setDatabaseName(m_dbName);
     if (!db.open()) {
         /*: The placeholders are: %1 - The name of the database which cannot be opened
@@ -68,7 +70,7 @@ QString QHelpDBReader::namespaceName() const
     if (!m_namespace.isEmpty())
         return m_namespace;
     if (m_query) {
-        m_query->exec(QLatin1String("SELECT Name FROM NamespaceTable"));
+        m_query->exec("SELECT Name FROM NamespaceTable"_L1);
         if (m_query->next())
             m_namespace = m_query->value(0).toString();
     }
@@ -78,7 +80,7 @@ QString QHelpDBReader::namespaceName() const
 QString QHelpDBReader::virtualFolder() const
 {
     if (m_query) {
-        m_query->exec(QLatin1String("SELECT Name FROM FolderTable WHERE Id=1"));
+        m_query->exec("SELECT Name FROM FolderTable WHERE Id=1"_L1);
         if (m_query->next())
             return m_query->value(0).toString();
     }
@@ -87,7 +89,7 @@ QString QHelpDBReader::virtualFolder() const
 
 QString QHelpDBReader::version() const
 {
-    const QString versionString = metaData(QLatin1String("version")).toString();
+    const QString versionString = metaData("version"_L1).toString();
     if (versionString.isEmpty())
         return qtVersionHeuristic();
     return versionString;
@@ -96,12 +98,12 @@ QString QHelpDBReader::version() const
 QString QHelpDBReader::qtVersionHeuristic() const
 {
     const QString nameSpace = namespaceName();
-    if (!nameSpace.startsWith(QLatin1String("org.qt-project.")))
+    if (!nameSpace.startsWith("org.qt-project."_L1))
         return {};
 
     // We take the namespace tail, starting from the last letter in namespace name.
     // We drop any non digit characters.
-    const QChar dot(QLatin1Char('.'));
+    const QChar dot(u'.');
     QString tail;
     for (int i = nameSpace.size(); i > 0; --i) {
         const QChar c = nameSpace.at(i - 1);
@@ -172,7 +174,7 @@ QHelpDBReader::IndexTable QHelpDBReader::indexTable() const
         return table;
 
     QMap<int, QString> attributeIds;
-    m_query->exec(QLatin1String("SELECT DISTINCT Id, Name FROM FilterAttributeTable ORDER BY Id"));
+    m_query->exec("SELECT DISTINCT Id, Name FROM FilterAttributeTable ORDER BY Id"_L1);
     while (m_query->next())
         attributeIds.insert(m_query->value(0).toInt(), m_query->value(1).toString());
 
@@ -181,27 +183,22 @@ QHelpDBReader::IndexTable QHelpDBReader::indexTable() const
     QList<int> usedAttributeIds;
     for (auto it = attributeIds.cbegin(), end = attributeIds.cend(); it != end; ++it) {
         const int attributeId = it.key();
-        if (isAttributeUsed(m_query.get(), QLatin1String("IndexFilterTable"), attributeId)
-            || isAttributeUsed(m_query.get(), QLatin1String("ContentsFilterTable"), attributeId)
-            || isAttributeUsed(m_query.get(), QLatin1String("FileFilterTable"), attributeId)) {
+        if (isAttributeUsed(m_query.get(), "IndexFilterTable"_L1, attributeId)
+            || isAttributeUsed(m_query.get(), "ContentsFilterTable"_L1, attributeId)
+            || isAttributeUsed(m_query.get(), "FileFilterTable"_L1, attributeId)) {
             usedAttributeIds.append(attributeId);
         }
     }
 
     bool legacy = false;
-    m_query->exec(QLatin1String("SELECT * FROM pragma_table_info('IndexTable') "
-                                "WHERE name='ContextName'"));
+    m_query->exec("SELECT * FROM pragma_table_info('IndexTable') WHERE name='ContextName'"_L1);
     if (m_query->next())
         legacy = true;
 
-    const QString identifierColumnName = legacy
-            ? QLatin1String("ContextName")
-            : QLatin1String("Identifier");
-
+    const QString identifierColumnName = legacy ? "ContextName"_L1 : "Identifier"_L1;
     const int usedAttributeCount = usedAttributeIds.size();
 
     QMap<int, IndexItem> idToIndexItem;
-
     m_query->exec(QString::fromLatin1("SELECT Name, %1, FileId, Anchor, Id "
                                       "FROM IndexTable "
                                       "ORDER BY Id").arg(identifierColumnName));
@@ -220,13 +217,14 @@ QHelpDBReader::IndexTable QHelpDBReader::indexTable() const
     QMap<int, int> originalFileIdToNewFileId;
 
     int filesCount = 0;
-    m_query->exec(QLatin1String("SELECT "
-                                    "FileNameTable.FileId, "
-                                    "FileNameTable.Name, "
-                                    "FileNameTable.Title "
-                                "FROM FileNameTable, FolderTable "
-                                "WHERE FileNameTable.FolderId = FolderTable.Id "
-                                "ORDER BY FileId"));
+    m_query->exec(
+        "SELECT "
+            "FileNameTable.FileId, "
+            "FileNameTable.Name, "
+            "FileNameTable.Title "
+        "FROM FileNameTable, FolderTable "
+        "WHERE FileNameTable.FolderId = FolderTable.Id "
+        "ORDER BY FileId"_L1);
     while (m_query->next()) {
         const int fileId = m_query->value(0).toInt();
         FileItem fileItem;
@@ -240,9 +238,7 @@ QHelpDBReader::IndexTable QHelpDBReader::indexTable() const
 
     QMap<int, ContentsItem> idToContentsItem;
 
-    m_query->exec(QLatin1String("SELECT Data, Id "
-                                "FROM ContentsTable "
-                                "ORDER BY Id"));
+    m_query->exec("SELECT Data, Id FROM ContentsTable ORDER BY Id"_L1);
     while (m_query->next()) {
         ContentsItem contentsItem;
         contentsItem.data    = m_query->value(0).toByteArray();
@@ -262,27 +258,25 @@ QHelpDBReader::IndexTable QHelpDBReader::indexTable() const
         // which we want to optimize). The same with FileNameTable and
         // FileFilterTable.
 
-        const bool mayOptimizeIndexTable
-                = filterDataCount(m_query.get(), QLatin1String("IndexFilterTable"))
+        const bool mayOptimizeIndexTable = filterDataCount(m_query.get(), "IndexFilterTable"_L1)
                 == idToIndexItem.size() * usedAttributeCount;
-        const bool mayOptimizeFileTable
-                = filterDataCount(m_query.get(), QLatin1String("FileFilterTable"))
+        const bool mayOptimizeFileTable = filterDataCount(m_query.get(), "FileFilterTable"_L1)
                 == idToFileItem.size() * usedAttributeCount;
-        const bool mayOptimizeContentsTable
-                = filterDataCount(m_query.get(), QLatin1String("ContentsFilterTable"))
+        const bool mayOptimizeContentsTable =
+                filterDataCount(m_query.get(), "ContentsFilterTable"_L1)
                 == idToContentsItem.size() * usedAttributeCount;
         optimized = mayOptimizeIndexTable && mayOptimizeFileTable && mayOptimizeContentsTable;
 
         if (!optimized) {
-            m_query->exec(QLatin1String(
-                              "SELECT "
-                                  "IndexFilterTable.IndexId, "
-                                  "FilterAttributeTable.Name "
-                              "FROM "
-                                  "IndexFilterTable, "
-                                  "FilterAttributeTable "
-                              "WHERE "
-                                  "IndexFilterTable.FilterAttributeId = FilterAttributeTable.Id"));
+            m_query->exec(
+                "SELECT "
+                    "IndexFilterTable.IndexId, "
+                    "FilterAttributeTable.Name "
+                "FROM "
+                    "IndexFilterTable, "
+                    "FilterAttributeTable "
+                "WHERE "
+                    "IndexFilterTable.FilterAttributeId = FilterAttributeTable.Id"_L1);
             while (m_query->next()) {
                 const int indexId = m_query->value(0).toInt();
                 auto it = idToIndexItem.find(indexId);
@@ -290,15 +284,15 @@ QHelpDBReader::IndexTable QHelpDBReader::indexTable() const
                     it.value().filterAttributes.append(m_query->value(1).toString());
             }
 
-            m_query->exec(QLatin1String(
-                              "SELECT "
-                                  "FileFilterTable.FileId, "
-                                  "FilterAttributeTable.Name "
-                              "FROM "
-                                  "FileFilterTable, "
-                                  "FilterAttributeTable "
-                              "WHERE "
-                                  "FileFilterTable.FilterAttributeId = FilterAttributeTable.Id"));
+            m_query->exec(
+                "SELECT "
+                    "FileFilterTable.FileId, "
+                    "FilterAttributeTable.Name "
+                "FROM "
+                    "FileFilterTable, "
+                    "FilterAttributeTable "
+                "WHERE "
+                    "FileFilterTable.FilterAttributeId = FilterAttributeTable.Id"_L1);
             while (m_query->next()) {
                 const int fileId = m_query->value(0).toInt();
                 auto it = idToFileItem.find(fileId);
@@ -306,15 +300,15 @@ QHelpDBReader::IndexTable QHelpDBReader::indexTable() const
                     it.value().filterAttributes.append(m_query->value(1).toString());
             }
 
-            m_query->exec(QLatin1String(
-                              "SELECT "
-                                  "ContentsFilterTable.ContentsId, "
-                                  "FilterAttributeTable.Name "
-                              "FROM "
-                                  "ContentsFilterTable, "
-                                  "FilterAttributeTable "
-                              "WHERE "
-                                  "ContentsFilterTable.FilterAttributeId = FilterAttributeTable.Id"));
+            m_query->exec(
+                "SELECT "
+                    "ContentsFilterTable.ContentsId, "
+                    "FilterAttributeTable.Name "
+                "FROM "
+                    "ContentsFilterTable, "
+                    "FilterAttributeTable "
+                "WHERE "
+                    "ContentsFilterTable.FilterAttributeId = FilterAttributeTable.Id"_L1);
             while (m_query->next()) {
                 const int contentsId = m_query->value(0).toInt();
                 auto it = idToContentsItem.find(contentsId);
@@ -345,15 +339,15 @@ QList<QStringList> QHelpDBReader::filterAttributeSets() const
 {
     QList<QStringList> result;
     if (m_query) {
-        m_query->exec(QLatin1String(
-                  "SELECT "
-                      "FileAttributeSetTable.Id, "
-                      "FilterAttributeTable.Name "
-                  "FROM "
-                      "FileAttributeSetTable, "
-                      "FilterAttributeTable "
-                  "WHERE FileAttributeSetTable.FilterAttributeId = FilterAttributeTable.Id "
-                  "ORDER BY FileAttributeSetTable.Id"));
+        m_query->exec(
+            "SELECT "
+                "FileAttributeSetTable.Id, "
+                "FilterAttributeTable.Name "
+            "FROM "
+                "FileAttributeSetTable, "
+                "FilterAttributeTable "
+            "WHERE FileAttributeSetTable.FilterAttributeId = FilterAttributeTable.Id "
+            "ORDER BY FileAttributeSetTable.Id"_L1);
         int oldId = -1;
         while (m_query->next()) {
             const int id = m_query->value(0).toInt();
@@ -375,22 +369,22 @@ QByteArray QHelpDBReader::fileData(const QString &virtualFolder,
         return ba;
 
     namespaceName();
-    m_query->prepare(QLatin1String(
-                    "SELECT "
-                        "FileDataTable.Data "
-                    "FROM "
-                        "FileDataTable, "
-                        "FileNameTable, "
-                        "FolderTable, "
-                        "NamespaceTable "
-                    "WHERE FileDataTable.Id = FileNameTable.FileId "
-                    "AND (FileNameTable.Name = ? OR FileNameTable.Name = ?) "
-                    "AND FileNameTable.FolderId = FolderTable.Id "
-                    "AND FolderTable.Name = ? "
-                    "AND FolderTable.NamespaceId = NamespaceTable.Id "
-                    "AND NamespaceTable.Name = ?"));
+    m_query->prepare(
+        "SELECT "
+            "FileDataTable.Data "
+        "FROM "
+            "FileDataTable, "
+            "FileNameTable, "
+            "FolderTable, "
+            "NamespaceTable "
+        "WHERE FileDataTable.Id = FileNameTable.FileId "
+        "AND (FileNameTable.Name = ? OR FileNameTable.Name = ?) "
+        "AND FileNameTable.FolderId = FolderTable.Id "
+        "AND FolderTable.Name = ? "
+        "AND FolderTable.NamespaceId = NamespaceTable.Id "
+        "AND NamespaceTable.Name = ?"_L1);
     m_query->bindValue(0, filePath);
-    m_query->bindValue(1, QString(QLatin1String("./") + filePath));
+    m_query->bindValue(1, QString("./"_L1 + filePath));
     m_query->bindValue(2, virtualFolder);
     m_query->bindValue(3, m_namespace);
     m_query->exec();
@@ -403,7 +397,7 @@ QStringList QHelpDBReader::customFilters() const
 {
     QStringList lst;
     if (m_query) {
-        m_query->exec(QLatin1String("SELECT Name FROM FilterNameTable"));
+        m_query->exec("SELECT Name FROM FilterNameTable"_L1);
         while (m_query->next())
             lst.append(m_query->value(0).toString());
     }
@@ -415,18 +409,18 @@ QStringList QHelpDBReader::filterAttributes(const QString &filterName) const
     QStringList lst;
     if (m_query) {
         if (filterName.isEmpty()) {
-            m_query->prepare(QLatin1String("SELECT Name FROM FilterAttributeTable"));
+            m_query->prepare("SELECT Name FROM FilterAttributeTable"_L1);
         } else {
-            m_query->prepare(QLatin1String(
-                     "SELECT "
-                         "FilterAttributeTable.Name "
-                     "FROM "
-                         "FilterAttributeTable, "
-                         "FilterTable, "
-                         "FilterNameTable "
-                     "WHERE FilterNameTable.Name = ? "
-                    "AND FilterNameTable.Id = FilterTable.NameId "
-                    "AND FilterTable.FilterAttributeId = FilterAttributeTable.Id"));
+            m_query->prepare(
+                 "SELECT "
+                     "FilterAttributeTable.Name "
+                 "FROM "
+                     "FilterAttributeTable, "
+                     "FilterTable, "
+                     "FilterNameTable "
+                 "WHERE FilterNameTable.Name = ? "
+                "AND FilterNameTable.Id = FilterTable.NameId "
+                "AND FilterTable.FilterAttributeId = FilterAttributeTable.Id"_L1);
             m_query->bindValue(0, filterName);
         }
         m_query->exec();
@@ -445,40 +439,39 @@ QMultiMap<QString, QByteArray> QHelpDBReader::filesData(const QStringList &filte
     QString query;
     QString extension;
     if (!extensionFilter.isEmpty())
-        extension = QString(QLatin1String("AND FileNameTable.Name "
-                                          "LIKE \'%.%1\'")).arg(extensionFilter);
+        extension = "AND FileNameTable.Name LIKE \'%.%1\'"_L1.arg(extensionFilter);
 
     if (filterAttributes.isEmpty()) {
-        query = QString(QLatin1String("SELECT "
-                                          "FileNameTable.Name, "
-                                          "FileDataTable.Data "
-                                      "FROM "
-                                          "FolderTable, "
-                                          "FileNameTable, "
-                                          "FileDataTable "
-                                      "WHERE FileDataTable.Id = FileNameTable.FileId "
-                                      "AND FileNameTable.FolderId = FolderTable.Id %1"))
-            .arg(extension);
+        query =
+            "SELECT "
+                "FileNameTable.Name, "
+                "FileDataTable.Data "
+            "FROM "
+                "FolderTable, "
+                "FileNameTable, "
+                "FileDataTable "
+            "WHERE FileDataTable.Id = FileNameTable.FileId "
+            "AND FileNameTable.FolderId = FolderTable.Id %1"_L1.arg(extension);
     } else {
         for (int i = 0; i < filterAttributes.size(); ++i) {
             if (i > 0)
-                query.append(QLatin1String(" INTERSECT "));
-            query.append(QString(QLatin1String(
-                                     "SELECT "
-                                         "FileNameTable.Name, "
-                                         "FileDataTable.Data "
-                                     "FROM "
-                                         "FolderTable, "
-                                         "FileNameTable, "
-                                         "FileDataTable, "
-                                         "FileFilterTable, "
-                                         "FilterAttributeTable "
-                                     "WHERE FileDataTable.Id = FileNameTable.FileId "
-                                     "AND FileNameTable.FolderId = FolderTable.Id "
-                                     "AND FileNameTable.FileId = FileFilterTable.FileId "
-                                     "AND FileFilterTable.FilterAttributeId = FilterAttributeTable.Id "
-                                     "AND FilterAttributeTable.Name = \'%1\' %2"))
-                         .arg(quote(filterAttributes.at(i)), extension));
+                query.append(" INTERSECT "_L1);
+            query.append(
+                "SELECT "
+                    "FileNameTable.Name, "
+                    "FileDataTable.Data "
+                "FROM "
+                    "FolderTable, "
+                    "FileNameTable, "
+                    "FileDataTable, "
+                    "FileFilterTable, "
+                    "FilterAttributeTable "
+                "WHERE FileDataTable.Id = FileNameTable.FileId "
+                "AND FileNameTable.FolderId = FolderTable.Id "
+                "AND FileNameTable.FileId = FileFilterTable.FileId "
+                "AND FileFilterTable.FilterAttributeId = FilterAttributeTable.Id "
+                "AND FilterAttributeTable.Name = \'%1\' %2"_L1
+                            .arg(quote(filterAttributes.at(i)), extension));
         }
     }
     m_query->exec(query);
@@ -493,7 +486,7 @@ QVariant QHelpDBReader::metaData(const QString &name) const
     if (!m_query)
         return {};
 
-    m_query->prepare(QLatin1String("SELECT COUNT(Value), Value FROM MetaDataTable WHERE Name=?"));
+    m_query->prepare("SELECT COUNT(Value), Value FROM MetaDataTable WHERE Name=?"_L1);
     m_query->bindValue(0, name);
     if (m_query->exec() && m_query->next() && m_query->value(0).toInt() == 1)
         return m_query->value(1);
@@ -503,7 +496,7 @@ QVariant QHelpDBReader::metaData(const QString &name) const
 QString QHelpDBReader::quote(const QString &string) const
 {
     QString s = string;
-    s.replace(QLatin1Char('\''), QLatin1String("\'\'"));
+    s.replace(u'\'', "\'\'"_L1);
     return s;
 }
 
diff --git a/src/assistant/help/qhelpdbreader_p.h b/src/assistant/help/qhelpdbreader_p.h
index 2c464250a..1bc4fc7c9 100644
--- a/src/assistant/help/qhelpdbreader_p.h
+++ b/src/assistant/help/qhelpdbreader_p.h
@@ -97,4 +97,4 @@ private:
 
 QT_END_NAMESPACE
 
-#endif
+#endif // QHELPDBREADER_H
diff --git a/src/assistant/help/qhelpengine.h b/src/assistant/help/qhelpengine.h
index 219ff3818..31b8fb3ef 100644
--- a/src/assistant/help/qhelpengine.h
+++ b/src/assistant/help/qhelpengine.h
@@ -39,4 +39,4 @@ private:
 
 QT_END_NAMESPACE
 
-#endif
+#endif // QHELPENGINE_H
diff --git a/src/assistant/help/qhelpenginecore.cpp b/src/assistant/help/qhelpenginecore.cpp
index 130aaf9cc..e5dc4aa63 100644
--- a/src/assistant/help/qhelpenginecore.cpp
+++ b/src/assistant/help/qhelpenginecore.cpp
@@ -349,7 +349,7 @@ QString QHelpEngineCore::documentationFileName(const QString &namespaceName)
         return fileInfo.fileName;
 
     return QFileInfo(QFileInfo(d->collectionHandler->collectionFile()).absolutePath()
-                     + QLatin1Char('/') + fileInfo.fileName).absoluteFilePath();
+                     + u'/' + fileInfo.fileName).absoluteFilePath();
 }
 
 /*!
@@ -469,8 +469,8 @@ QString QHelpEngineCore::currentFilter() const
         return {};
 
     if (d->currentFilter.isEmpty()) {
-        const QString &filter = d->collectionHandler->customValue(
-                    QLatin1String("CurrentFilter"), QString()).toString();
+        const QString &filter =
+                d->collectionHandler->customValue("CurrentFilter"_L1, QString()).toString();
         if (!filter.isEmpty() && d->collectionHandler->customFilters().contains(filter))
             d->currentFilter = filter;
     }
@@ -483,7 +483,7 @@ void QHelpEngineCore::setCurrentFilter(const QString &filterName)
         return;
     d->currentFilter = filterName;
     if (d->autoSaveFilter)
-        d->collectionHandler->setCustomValue(QLatin1String("CurrentFilter"), d->currentFilter);
+        d->collectionHandler->setCustomValue("CurrentFilter"_L1, d->currentFilter);
     emit currentFilterChanged(d->currentFilter);
 }
 
@@ -521,13 +521,13 @@ QList<QUrl> QHelpEngineCore::files(const QString namespaceName,
         return res;
 
     QUrl url;
-    url.setScheme(QLatin1String("qthelp"));
+    url.setScheme("qthelp"_L1);
     url.setAuthority(namespaceName);
 
     const QStringList &files = d->collectionHandler->files(
                 namespaceName, filterAttributes, extensionFilter);
     for (const QString &file : files) {
-        url.setPath(QLatin1String("/") + file);
+        url.setPath("/"_L1 + file);
         res.append(url);
     }
     return res;
@@ -547,13 +547,13 @@ QList<QUrl> QHelpEngineCore::files(const QString namespaceName,
         return res;
 
     QUrl url;
-    url.setScheme(QLatin1String("qthelp"));
+    url.setScheme("qthelp"_L1);
     url.setAuthority(namespaceName);
 
     const QStringList &files = d->collectionHandler->files(
                 namespaceName, filterName, extensionFilter);
     for (const QString &file : files) {
-        url.setPath(QLatin1String("/") + file);
+        url.setPath("/"_L1 + file);
         res.append(url);
     }
     return res;
@@ -715,7 +715,7 @@ bool QHelpEngineCore::setCustomValue(const QString &key, const QVariant &value)
 QVariant QHelpEngineCore::metaData(const QString &documentationFileName,
                                    const QString &name)
 {
-    QHelpDBReader reader(documentationFileName, QLatin1String("GetMetaData"), nullptr);
+    QHelpDBReader reader(documentationFileName, "GetMetaData"_L1, nullptr);
 
     if (reader.init())
         return reader.metaData(name);
@@ -780,7 +780,7 @@ bool QHelpEngineCore::usesFilterEngine() const
 static QUrl constructUrl(const QString &namespaceName, const QString &folderName,
                          const QString &relativePath)
 {
-    const int idx = relativePath.indexOf(QLatin1Char('#'));
+    const int idx = relativePath.indexOf(u'#');
     const QString &rp = idx < 0 ? relativePath : relativePath.left(idx);
     const QString anchor = idx < 0 ? QString() : relativePath.mid(idx + 1);
     return QHelpCollectionHandler::buildQUrl(namespaceName, folderName, rp, anchor);
diff --git a/src/assistant/help/qhelpfilterengine.cpp b/src/assistant/help/qhelpfilterengine.cpp
index 0253e7af0..dc139bffd 100644
--- a/src/assistant/help/qhelpfilterengine.cpp
+++ b/src/assistant/help/qhelpfilterengine.cpp
@@ -44,7 +44,7 @@ bool QHelpFilterEnginePrivate::setup()
     }
 
     const QString filter = m_collectionHandler->customValue(
-                QLatin1String(ActiveFilter), QString()).toString();
+                QLatin1StringView(ActiveFilter), QString()).toString();
     if (!filter.isEmpty() && m_collectionHandler->filters().contains(filter))
         m_currentFilter = filter;
 
@@ -248,9 +248,7 @@ bool QHelpFilterEngine::setActiveFilter(const QString &filterName)
         return false;
 
     d->m_currentFilter = filterName;
-    d->m_collectionHandler->setCustomValue(QLatin1String(ActiveFilter),
-            d->m_currentFilter);
-
+    d->m_collectionHandler->setCustomValue(QLatin1StringView(ActiveFilter), d->m_currentFilter);
     emit filterActivated(d->m_currentFilter);
     return true;
 }
diff --git a/src/assistant/help/qhelpfiltersettingswidget.cpp b/src/assistant/help/qhelpfiltersettingswidget.cpp
index 04d2aea4e..319111f6c 100644
--- a/src/assistant/help/qhelpfiltersettingswidget.cpp
+++ b/src/assistant/help/qhelpfiltersettingswidget.cpp
@@ -13,6 +13,8 @@
 
 QT_BEGIN_NAMESPACE
 
+using namespace Qt::StringLiterals;
+
 class QHelpFilterSettings final
 {
 public:
@@ -307,7 +309,7 @@ QString QHelpFilterSettingsWidgetPrivate::suggestedNewFilterName(const QString &
     QString newFilterName = initialFilterName;
     int counter = 1;
     while (m_filterToItem.contains(newFilterName))
-        newFilterName = initialFilterName + QLatin1Char(' ') + QString::number(++counter);
+        newFilterName = initialFilterName + u' ' + QString::number(++counter);
     return newFilterName;
 }
 
@@ -343,14 +345,14 @@ QHelpFilterSettingsWidget::QHelpFilterSettingsWidget(QWidget *parent)
     d->m_ui.setupUi(this);
 
     // TODO: make resources configurable
-    QString resourcePath = QLatin1String(":/qt-project.org/assistant/images/");
+    QString resourcePath = ":/qt-project.org/assistant/images/"_L1;
 #ifdef Q_OS_MACOS
-    resourcePath.append(QLatin1String("mac"));
+    resourcePath.append("mac"_L1);
 #else
-    resourcePath.append(QLatin1String("win"));
+    resourcePath.append("win"_L1);
 #endif
-    d->m_ui.addButton->setIcon(QIcon(resourcePath + QLatin1String("/plus.png")));
-    d->m_ui.removeButton->setIcon(QIcon(resourcePath + QLatin1String("/minus.png")));
+    d->m_ui.addButton->setIcon(QIcon(resourcePath + "/plus.png"_L1));
+    d->m_ui.removeButton->setIcon(QIcon(resourcePath + "/minus.png"_L1));
 
     connect(d->m_ui.componentWidget, &QOptionsWidget::optionSelectionChanged,
             this, [this](const QStringList &options) {
diff --git a/src/assistant/help/qhelpindexwidget.h b/src/assistant/help/qhelpindexwidget.h
index 15bb43954..c3518367b 100644
--- a/src/assistant/help/qhelpindexwidget.h
+++ b/src/assistant/help/qhelpindexwidget.h
@@ -74,4 +74,4 @@ private:
 
 QT_END_NAMESPACE
 
-#endif
+#endif // QHELPINDEXWIDGET_H
diff --git a/src/assistant/help/qhelpsearchengine.h b/src/assistant/help/qhelpsearchengine.h
index e09f9ac07..f782e6174 100644
--- a/src/assistant/help/qhelpsearchengine.h
+++ b/src/assistant/help/qhelpsearchengine.h
@@ -89,4 +89,4 @@ private:
 
 QT_END_NAMESPACE
 
-#endif  // QHELPSEARCHENGINE_H
+#endif // QHELPSEARCHENGINE_H
diff --git a/src/assistant/help/qhelpsearchenginecore.cpp b/src/assistant/help/qhelpsearchenginecore.cpp
index a8b032b3d..5f8c3c7c8 100644
--- a/src/assistant/help/qhelpsearchenginecore.cpp
+++ b/src/assistant/help/qhelpsearchenginecore.cpp
@@ -16,17 +16,18 @@
 QT_BEGIN_NAMESPACE
 
 using namespace fulltextsearch;
+using namespace Qt::StringLiterals;
 
 class QHelpSearchEngineCorePrivate
 {
 public:
     QString indexFilesFolder() const
     {
-        QString indexFilesFolder = QLatin1String(".fulltextsearch");
+        QString indexFilesFolder = ".fulltextsearch"_L1;
         if (m_helpEngine && !m_helpEngine->collectionFile().isEmpty()) {
             const QFileInfo fi(m_helpEngine->collectionFile());
-            indexFilesFolder = fi.absolutePath() + QDir::separator() + QLatin1Char('.')
-                    + fi.fileName().left(fi.fileName().lastIndexOf(QLatin1String(".qhc")));
+            indexFilesFolder = fi.absolutePath() + QDir::separator() + u'.'
+                    + fi.fileName().left(fi.fileName().lastIndexOf(".qhc"_L1));
         }
         return indexFilesFolder;
     }
diff --git a/src/assistant/help/qhelpsearchenginecore.h b/src/assistant/help/qhelpsearchenginecore.h
index c3da3d1d4..d820a8f3d 100644
--- a/src/assistant/help/qhelpsearchenginecore.h
+++ b/src/assistant/help/qhelpsearchenginecore.h
@@ -48,4 +48,4 @@ private:
 
 QT_END_NAMESPACE
 
-#endif  // QHELPSEARCHENGINECORE_H
+#endif // QHELPSEARCHENGINECORE_H
diff --git a/src/assistant/help/qhelpsearchindexreader.cpp b/src/assistant/help/qhelpsearchindexreader.cpp
index 8d7c16d7f..5fd583335 100644
--- a/src/assistant/help/qhelpsearchindexreader.cpp
+++ b/src/assistant/help/qhelpsearchindexreader.cpp
@@ -12,6 +12,8 @@
 
 QT_BEGIN_NAMESPACE
 
+using namespace Qt::StringLiterals;
+
 namespace fulltextsearch {
 
 class Reader
@@ -57,8 +59,8 @@ static QString namespacePlaceholders(const QMultiMap<QString, QStringList> &name
         if (firstNS)
             firstNS = false;
         else
-            placeholders += QLatin1String(" OR ");
-        placeholders += QLatin1String("(namespace = ?");
+            placeholders += " OR "_L1;
+        placeholders += "(namespace = ?"_L1;
 
         const QList<QStringList> &attributeSets = namespaces.values(ns);
         bool firstAS = true;
@@ -66,16 +68,16 @@ static QString namespacePlaceholders(const QMultiMap<QString, QStringList> &name
             if (!attributeSet.isEmpty()) {
                 if (firstAS) {
                     firstAS = false;
-                    placeholders += QLatin1String(" AND (");
+                    placeholders += " AND ("_L1;
                 } else {
-                    placeholders += QLatin1String(" OR ");
+                    placeholders += " OR "_L1;
                 }
-                placeholders += QLatin1String("attributes = ?");
+                placeholders += "attributes = ?"_L1;
             }
         }
         if (!firstAS)
-            placeholders += QLatin1Char(')'); // close "AND ("
-        placeholders += QLatin1Char(')');
+            placeholders += u')'; // close "AND ("
+        placeholders += u')';
     }
     return placeholders;
 }
@@ -90,7 +92,7 @@ static void bindNamespacesAndAttributes(QSqlQuery *query,
         const QList<QStringList> &attributeSets = namespaces.values(ns);
         for (const QStringList &attributeSet : attributeSets) {
             if (!attributeSet.isEmpty())
-                query->addBindValue(attributeSet.join(QLatin1Char('|')));
+                query->addBindValue(attributeSet.join(u'|'));
         }
     }
 }
@@ -103,8 +105,8 @@ static QString namespacePlaceholders(const QStringList &namespaceList)
         if (firstNS)
             firstNS = false;
         else
-            placeholders += QLatin1String(" OR ");
-        placeholders += QLatin1String("namespace = ?");
+            placeholders += " OR "_L1;
+        placeholders += "namespace = ?"_L1;
     }
     return placeholders;
 }
@@ -122,11 +124,11 @@ QList<QHelpSearchResult> Reader::queryTable(const QSqlDatabase &db, const QStrin
             ? namespacePlaceholders(m_filterEngineNamespaceList)
             : namespacePlaceholders(m_namespaceAttributes);
     QSqlQuery query(db);
-    query.prepare(QLatin1String("SELECT url, title, snippet(") + tableName +
-                  QLatin1String(", -1, '<b>', '</b>', '...', '10') FROM ") + tableName +
-                  QLatin1String(" WHERE (") + nsPlaceholders +
-                  QLatin1String(") AND ") + tableName +
-                  QLatin1String(" MATCH ? ORDER BY rank"));
+    query.prepare("SELECT url, title, snippet("_L1 + tableName +
+                  ", -1, '<b>', '</b>', '...', '10') FROM "_L1 + tableName +
+                  " WHERE ("_L1 + nsPlaceholders +
+                  ") AND "_L1 + tableName +
+                  " MATCH ? ORDER BY rank"_L1);
     m_useFilterEngine
             ? bindNamespacesAndAttributes(&query, m_filterEngineNamespaceList)
             : bindNamespacesAndAttributes(&query, m_namespaceAttributes);
@@ -136,8 +138,8 @@ QList<QHelpSearchResult> Reader::queryTable(const QSqlDatabase &db, const QStrin
     QList<QHelpSearchResult> results;
 
     while (query.next()) {
-        const QString &url = query.value(QLatin1String("url")).toString();
-        const QString &title = query.value(QLatin1String("title")).toString();
+        const QString &url = query.value("url"_L1).toString();
+        const QString &title = query.value("title"_L1).toString();
         const QString &snippet = query.value(2).toString();
         results.append(QHelpSearchResult(url, title, snippet));
     }
@@ -146,18 +148,16 @@ QList<QHelpSearchResult> Reader::queryTable(const QSqlDatabase &db, const QStrin
 
 void Reader::searchInDB(const QString &searchInput)
 {
-    const QString &uniqueId =
-            QHelpGlobal::uniquifyConnectionName(QLatin1String("QHelpReader"), this);
+    const QString &uniqueId = QHelpGlobal::uniquifyConnectionName("QHelpReader"_L1, this);
     {
-        QSqlDatabase db = QSqlDatabase::addDatabase(QLatin1String("QSQLITE"), uniqueId);
-        db.setConnectOptions(QLatin1String("QSQLITE_OPEN_READONLY"));
-        db.setDatabaseName(m_indexPath + QLatin1String("/fts"));
+        QSqlDatabase db = QSqlDatabase::addDatabase("QSQLITE"_L1, uniqueId);
+        db.setConnectOptions("QSQLITE_OPEN_READONLY"_L1);
+        db.setDatabaseName(m_indexPath + "/fts"_L1);
 
         if (db.open()) {
-            const QList<QHelpSearchResult> titleResults =
-                    queryTable(db, QLatin1String("titles"), searchInput);
+            const QList<QHelpSearchResult> titleResults = queryTable(db, "titles"_L1, searchInput);
             const QList<QHelpSearchResult> contentResults =
-                    queryTable(db, QLatin1String("contents"), searchInput);
+                    queryTable(db, "contents"_L1, searchInput);
 
             // merge results form title and contents searches
             m_searchResults.clear();
@@ -286,6 +286,6 @@ void QHelpSearchIndexReader::run()
     emit searchingFinished(m_searchResults.size());
 }
 
-}   // namespace fulltextsearch
+} // namespace fulltextsearch
 
 QT_END_NAMESPACE
diff --git a/src/assistant/help/qhelpsearchindexreader_p.h b/src/assistant/help/qhelpsearchindexreader_p.h
index a54df4ded..835c44f97 100644
--- a/src/assistant/help/qhelpsearchindexreader_p.h
+++ b/src/assistant/help/qhelpsearchindexreader_p.h
@@ -55,8 +55,8 @@ private:
     bool m_usesFilterEngine = false;
 };
 
-}   // namespace fulltextsearch
+} // namespace fulltextsearch
 
 QT_END_NAMESPACE
 
-#endif  // QHELPSEARCHINDEXREADER_H
+#endif // QHELPSEARCHINDEXREADER_H
diff --git a/src/assistant/help/qhelpsearchindexwriter.cpp b/src/assistant/help/qhelpsearchindexwriter.cpp
index 36ab3f805..2cccbade3 100644
--- a/src/assistant/help/qhelpsearchindexwriter.cpp
+++ b/src/assistant/help/qhelpsearchindexwriter.cpp
@@ -21,6 +21,8 @@
 
 QT_BEGIN_NAMESPACE
 
+using namespace Qt::StringLiterals;
+
 namespace fulltextsearch {
 
 const char FTS_DB_NAME[] = "fts";
@@ -66,9 +68,9 @@ Writer::Writer(const QString &path)
 {
     clearLegacyIndex();
     QDir().mkpath(m_dbDir);
-    m_uniqueId = QHelpGlobal::uniquifyConnectionName(QLatin1String("QHelpWriter"), this);
-    m_db = QSqlDatabase::addDatabase(QLatin1String("QSQLITE"), m_uniqueId);
-    const QString dbPath = m_dbDir + QLatin1Char('/') + QLatin1String(FTS_DB_NAME);
+    m_uniqueId = QHelpGlobal::uniquifyConnectionName("QHelpWriter"_L1, this);
+    m_db = QSqlDatabase::addDatabase("QSQLITE"_L1, m_uniqueId);
+    const QString dbPath = m_dbDir + u'/' + QLatin1StringView(FTS_DB_NAME);
     m_db.setDatabaseName(dbPath);
     if (!m_db.open()) {
         const QString &error = QHelpSearchIndexWriter::tr(
@@ -91,12 +93,11 @@ bool Writer::tryInit(bool reindex)
     QSqlQuery query(m_db);
     // HACK: we try to perform any modifying command just to check if
     // we don't get SQLITE_BUSY code (SQLITE_BUSY is defined to 5 in sqlite driver)
-    if (!query.exec(QLatin1String("CREATE TABLE foo ();"))) {
-        if (query.lastError().nativeErrorCode() == QLatin1String("5")) // db is locked
-            return false;
-    }
+    if (!query.exec("CREATE TABLE foo ();"_L1) && query.lastError().nativeErrorCode() == "5"_L1) // db is locked
+        return false;
+
     // HACK: clear what we have created
-    query.exec(QLatin1String("DROP TABLE foo;"));
+    query.exec("DROP TABLE foo;"_L1);
 
     init(reindex);
     return true;
@@ -108,7 +109,7 @@ bool Writer::hasDB()
         return false;
 
     QSqlQuery query(m_db);
-    query.prepare(QLatin1String("SELECT id FROM info LIMIT 1"));
+    query.prepare("SELECT id FROM info LIMIT 1"_L1);
     query.exec();
     return query.next();
 }
@@ -123,7 +124,7 @@ void Writer::clearLegacyIndex()
         return;
 
     const QStringList &list = dir.entryList(QDir::Files | QDir::Hidden);
-    if (!list.contains(QLatin1String(FTS_DB_NAME))) {
+    if (!list.contains(QLatin1StringView(FTS_DB_NAME))) {
         for (const QString &item : list)
             dir.remove(item);
     }
@@ -139,50 +140,50 @@ void Writer::init(bool reindex)
     if (reindex && hasDB()) {
         m_needOptimize = true;
 
-        query.exec(QLatin1String("DROP TABLE titles;"));
-        query.exec(QLatin1String("DROP TABLE contents;"));
-        query.exec(QLatin1String("DROP TABLE info;"));
+        query.exec("DROP TABLE titles;"_L1);
+        query.exec("DROP TABLE contents;"_L1);
+        query.exec("DROP TABLE info;"_L1);
     }
 
-    query.exec(QLatin1String("CREATE TABLE info (id INTEGER PRIMARY KEY, namespace, attributes, url, title, data);"));
-
-    query.exec(QLatin1String("CREATE VIRTUAL TABLE titles USING fts5("
-                             "namespace UNINDEXED, attributes UNINDEXED, "
-                             "url UNINDEXED, title, "
-                             "tokenize = 'porter unicode61', content = 'info', content_rowid='id');"));
-    query.exec(QLatin1String("CREATE TRIGGER titles_insert AFTER INSERT ON info BEGIN "
-                             "INSERT INTO titles(rowid, namespace, attributes, url, title) "
-                             "VALUES(new.id, new.namespace, new.attributes, new.url, new.title); "
-                             "END;"));
-    query.exec(QLatin1String("CREATE TRIGGER titles_delete AFTER DELETE ON info BEGIN "
-                             "INSERT INTO titles(titles, rowid, namespace, attributes, url, title) "
-                             "VALUES('delete', old.id, old.namespace, old.attributes, old.url, old.title); "
-                             "END;"));
-    query.exec(QLatin1String("CREATE TRIGGER titles_update AFTER UPDATE ON info BEGIN "
-                             "INSERT INTO titles(titles, rowid, namespace, attributes, url, title) "
-                             "VALUES('delete', old.id, old.namespace, old.attributes, old.url, old.title); "
-                             "INSERT INTO titles(rowid, namespace, attributes, url, title) "
-                             "VALUES(new.id, new.namespace, new.attributes, new.url, new.title); "
-                             "END;"));
-
-    query.exec(QLatin1String("CREATE VIRTUAL TABLE contents USING fts5("
-                             "namespace UNINDEXED, attributes UNINDEXED, "
-                             "url UNINDEXED, title, data, "
-                             "tokenize = 'porter unicode61', content = 'info', content_rowid='id');"));
-    query.exec(QLatin1String("CREATE TRIGGER contents_insert AFTER INSERT ON info BEGIN "
-                             "INSERT INTO contents(rowid, namespace, attributes, url, title, data) "
-                             "VALUES(new.id, new.namespace, new.attributes, new.url, new.title, new.data); "
-                             "END;"));
-    query.exec(QLatin1String("CREATE TRIGGER contents_delete AFTER DELETE ON info BEGIN "
-                             "INSERT INTO contents(contents, rowid, namespace, attributes, url, title, data) "
-                             "VALUES('delete', old.id, old.namespace, old.attributes, old.url, old.title, old.data); "
-                             "END;"));
-    query.exec(QLatin1String("CREATE TRIGGER contents_update AFTER UPDATE ON info BEGIN "
-                             "INSERT INTO contents(contents, rowid, namespace, attributes, url, title, data) "
-                             "VALUES('delete', old.id, old.namespace, old.attributes, old.url, old.title, old.data); "
-                             "INSERT INTO contents(rowid, namespace, attributes, url, title, data) "
-                             "VALUES(new.id, new.namespace, new.attributes, new.url, new.title, new.data); "
-                             "END;"));
+    query.exec("CREATE TABLE info (id INTEGER PRIMARY KEY, namespace, attributes, url, title, data);"_L1);
+
+    query.exec("CREATE VIRTUAL TABLE titles USING fts5("
+               "namespace UNINDEXED, attributes UNINDEXED, "
+               "url UNINDEXED, title, "
+               "tokenize = 'porter unicode61', content = 'info', content_rowid='id');"_L1);
+    query.exec("CREATE TRIGGER titles_insert AFTER INSERT ON info BEGIN "
+               "INSERT INTO titles(rowid, namespace, attributes, url, title) "
+               "VALUES(new.id, new.namespace, new.attributes, new.url, new.title); "
+               "END;"_L1);
+    query.exec("CREATE TRIGGER titles_delete AFTER DELETE ON info BEGIN "
+               "INSERT INTO titles(titles, rowid, namespace, attributes, url, title) "
+               "VALUES('delete', old.id, old.namespace, old.attributes, old.url, old.title); "
+               "END;"_L1);
+    query.exec("CREATE TRIGGER titles_update AFTER UPDATE ON info BEGIN "
+               "INSERT INTO titles(titles, rowid, namespace, attributes, url, title) "
+               "VALUES('delete', old.id, old.namespace, old.attributes, old.url, old.title); "
+               "INSERT INTO titles(rowid, namespace, attributes, url, title) "
+               "VALUES(new.id, new.namespace, new.attributes, new.url, new.title); "
+               "END;"_L1);
+
+    query.exec("CREATE VIRTUAL TABLE contents USING fts5("
+               "namespace UNINDEXED, attributes UNINDEXED, "
+               "url UNINDEXED, title, data, "
+               "tokenize = 'porter unicode61', content = 'info', content_rowid='id');"_L1);
+    query.exec("CREATE TRIGGER contents_insert AFTER INSERT ON info BEGIN "
+               "INSERT INTO contents(rowid, namespace, attributes, url, title, data) "
+               "VALUES(new.id, new.namespace, new.attributes, new.url, new.title, new.data); "
+               "END;"_L1);
+    query.exec("CREATE TRIGGER contents_delete AFTER DELETE ON info BEGIN "
+               "INSERT INTO contents(contents, rowid, namespace, attributes, url, title, data) "
+               "VALUES('delete', old.id, old.namespace, old.attributes, old.url, old.title, old.data); "
+               "END;"_L1);
+    query.exec("CREATE TRIGGER contents_update AFTER UPDATE ON info BEGIN "
+               "INSERT INTO contents(contents, rowid, namespace, attributes, url, title, data) "
+               "VALUES('delete', old.id, old.namespace, old.attributes, old.url, old.title, old.data); "
+               "INSERT INTO contents(rowid, namespace, attributes, url, title, data) "
+               "VALUES(new.id, new.namespace, new.attributes, new.url, new.title, new.data); "
+               "END;"_L1);
 }
 
 Writer::~Writer()
@@ -200,7 +201,7 @@ void Writer::flush()
         return;
 
     QSqlQuery query(m_db);
-    query.prepare(QLatin1String("INSERT INTO info (namespace, attributes, url, title, data) VALUES (?, ?, ?, ?, ?)"));
+    query.prepare("INSERT INTO info (namespace, attributes, url, title, data) VALUES (?, ?, ?, ?, ?)"_L1);
     query.addBindValue(m_namespaces);
     query.addBindValue(m_attributes);
     query.addBindValue(m_urls);
@@ -222,7 +223,7 @@ void Writer::removeNamespace(const QString &namespaceName)
 
     m_needOptimize = true;
     QSqlQuery query(m_db);
-    query.prepare(QLatin1String("DELETE FROM info WHERE namespace = ?"));
+    query.prepare("DELETE FROM info WHERE namespace = ?"_L1);
     query.addBindValue(namespaceName);
     query.exec();
 }
@@ -233,7 +234,7 @@ bool Writer::hasNamespace(const QString &namespaceName)
         return false;
 
     QSqlQuery query(m_db);
-    query.prepare(QLatin1String("SELECT id FROM info WHERE namespace = ? LIMIT 1"));
+    query.prepare("SELECT id FROM info WHERE namespace = ? LIMIT 1"_L1);
     query.addBindValue(namespaceName);
     query.exec();
     return query.next();
@@ -270,15 +271,15 @@ void Writer::endTransaction()
     QSqlQuery query(m_db);
 
     if (m_needOptimize) {
-        query.exec(QLatin1String("INSERT INTO titles(titles) VALUES('rebuild')"));
-        query.exec(QLatin1String("INSERT INTO contents(contents) VALUES('rebuild')"));
+        query.exec("INSERT INTO titles(titles) VALUES('rebuild')"_L1);
+        query.exec("INSERT INTO contents(contents) VALUES('rebuild')"_L1);
     }
 
     if (m_db.driver()->hasFeature(QSqlDriver::Transactions))
         m_db.commit();
 
     if (m_needOptimize)
-        query.exec(QLatin1String("VACUUM"));
+        query.exec("VACUUM"_L1);
 }
 
 QHelpSearchIndexWriter::~QHelpSearchIndexWriter()
@@ -316,7 +317,8 @@ static const char IndexedNamespacesKey[] = "FTS5IndexedNamespaces";
 static QMap<QString, QDateTime> readIndexMap(const QHelpEngineCore &engine)
 {
     QMap<QString, QDateTime> indexMap;
-    QDataStream dataStream(engine.customValue(QLatin1String(IndexedNamespacesKey)).toByteArray());
+    QDataStream dataStream(
+            engine.customValue(QLatin1StringView(IndexedNamespacesKey)).toByteArray());
     dataStream >> indexMap;
     return indexMap;
 }
@@ -324,16 +326,14 @@ static QMap<QString, QDateTime> readIndexMap(const QHelpEngineCore &engine)
 static bool writeIndexMap(QHelpEngineCore *engine, const QMap<QString, QDateTime> &indexMap)
 {
     QByteArray data;
-
     QDataStream dataStream(&data, QIODevice::ReadWrite);
     dataStream << indexMap;
-
-    return engine->setCustomValue(QLatin1String(IndexedNamespacesKey), data);
+    return engine->setCustomValue(QLatin1StringView(IndexedNamespacesKey), data);
 }
 
 static bool clearIndexMap(QHelpEngineCore *engine)
 {
-    return engine->removeCustomValue(QLatin1String(IndexedNamespacesKey));
+    return engine->removeCustomValue(QLatin1StringView(IndexedNamespacesKey));
 }
 
 void QHelpSearchIndexWriter::run()
@@ -433,16 +433,13 @@ void QHelpSearchIndexWriter::run()
             engine.filterAttributeSets(namespaceName);
 
         for (const QStringList &attributes : attributeSets) {
-            const QString &attributesString = attributes.join(QLatin1Char('|'));
+            const QString &attributesString = attributes.join(u'|');
 
-            const QMultiMap<QString, QByteArray> htmlFiles =
-                    reader.filesData(attributes, QLatin1String("html"));
-            const QMultiMap<QString, QByteArray> htmFiles =
-                    reader.filesData(attributes, QLatin1String("htm"));
-            const QMultiMap<QString, QByteArray> txtFiles =
-                    reader.filesData(attributes, QLatin1String("txt"));
+            const auto htmlFiles = reader.filesData(attributes, "html"_L1);
+            const auto htmFiles = reader.filesData(attributes, "htm"_L1);
+            const auto txtFiles = reader.filesData(attributes, "txt"_L1);
 
-            QMultiMap<QString, QByteArray> files = htmlFiles;
+            auto files = htmlFiles;
             files.unite(htmFiles);
             files.unite(txtFiles);
 
@@ -464,17 +461,16 @@ void QHelpSearchIndexWriter::run()
                     continue;
 
                 QUrl url;
-                url.setScheme(QLatin1String("qthelp"));
+                url.setScheme("qthelp"_L1);
                 url.setAuthority(namespaceName);
-                url.setPath(QLatin1Char('/') + virtualFolder + QLatin1Char('/') + file);
+                url.setPath(u'/' + virtualFolder + u'/' + file);
 
                 if (url.hasFragment())
                     url.setFragment({});
 
                 const QString &fullFileName = url.toString();
-                if (!fullFileName.endsWith(QLatin1String(".html"))
-                        && !fullFileName.endsWith(QLatin1String(".htm"))
-                        && !fullFileName.endsWith(QLatin1String(".txt"))) {
+                if (!fullFileName.endsWith(".html"_L1) && !fullFileName.endsWith(".htm"_L1)
+                    && !fullFileName.endsWith(".txt"_L1)) {
                     continue;
                 }
 
@@ -489,8 +485,8 @@ void QHelpSearchIndexWriter::run()
 
                 QString title;
                 QString contents;
-                if (fullFileName.endsWith(QLatin1String(".txt"))) {
-                    title = fullFileName.mid(fullFileName.lastIndexOf(QLatin1Char('/')) + 1);
+                if (fullFileName.endsWith(".txt"_L1)) {
+                    title = fullFileName.mid(fullFileName.lastIndexOf(u'/') + 1);
                     contents = text.toHtmlEscaped();
                 } else {
                     QTextDocument doc;
@@ -514,6 +510,6 @@ void QHelpSearchIndexWriter::run()
     emit indexingFinished();
 }
 
-}   // namespace fulltextsearch
+} // namespace fulltextsearch
 
 QT_END_NAMESPACE
diff --git a/src/assistant/help/qhelpsearchindexwriter_p.h b/src/assistant/help/qhelpsearchindexwriter_p.h
index 0e3b17451..61e004794 100644
--- a/src/assistant/help/qhelpsearchindexwriter_p.h
+++ b/src/assistant/help/qhelpsearchindexwriter_p.h
@@ -51,8 +51,8 @@ private:
     QString m_indexFilesFolder;
 };
 
-}   // namespace fulltextsearch
+} // namespace fulltextsearch
 
 QT_END_NAMESPACE
 
-#endif  // QHELPSEARCHINDEXWRITER_H
+#endif // QHELPSEARCHINDEXWRITER_H
diff --git a/src/assistant/help/qhelpsearchquerywidget.h b/src/assistant/help/qhelpsearchquerywidget.h
index 7f633e0bd..148ae0f11 100644
--- a/src/assistant/help/qhelpsearchquerywidget.h
+++ b/src/assistant/help/qhelpsearchquerywidget.h
@@ -51,4 +51,4 @@ private:
 
 QT_END_NAMESPACE
 
-#endif  // QHELPSEARCHQUERYWIDGET_H
+#endif // QHELPSEARCHQUERYWIDGET_H
diff --git a/src/assistant/help/qhelpsearchresultwidget.h b/src/assistant/help/qhelpsearchresultwidget.h
index 9f5773576..859477eae 100644
--- a/src/assistant/help/qhelpsearchresultwidget.h
+++ b/src/assistant/help/qhelpsearchresultwidget.h
@@ -36,4 +36,4 @@ private:
 
 QT_END_NAMESPACE
 
-#endif  // QHELPSEARCHRESULTWIDGET_H
+#endif // QHELPSEARCHRESULTWIDGET_H
diff --git a/src/assistant/help/qoptionswidget.cpp b/src/assistant/help/qoptionswidget.cpp
index 688b4ed72..65713e722 100644
--- a/src/assistant/help/qoptionswidget.cpp
+++ b/src/assistant/help/qoptionswidget.cpp
@@ -9,13 +9,15 @@
 
 QT_BEGIN_NAMESPACE
 
+using namespace Qt::StringLiterals;
+
 class ListWidgetDelegate : public QItemDelegate
 {
 public:
     ListWidgetDelegate(QWidget *w) : QItemDelegate(w), m_widget(w) {}
 
     static bool isSeparator(const QModelIndex &index) {
-        return index.data(Qt::AccessibleDescriptionRole).toString() == QLatin1String("separator");
+        return index.data(Qt::AccessibleDescriptionRole).toString() == "separator"_L1;
     }
     static void setSeparator(QListWidgetItem *item) {
         item->setData(Qt::AccessibleDescriptionRole, QString::fromLatin1("separator"));
@@ -139,9 +141,9 @@ QString QOptionsWidget::optionText(const QString &optionName, bool valid) const
 {
     QString text = optionName;
     if (optionName.isEmpty())
-        text = QLatin1Char('[') + m_noOptionText + QLatin1Char(']');
+        text = u'[' + m_noOptionText + u']';
     if (!valid)
-        text += QLatin1String("\t[") + m_invalidOptionText + QLatin1Char(']');
+        text += "\t["_L1 + m_invalidOptionText + u']';
     return text;
 }
 
diff --git a/src/assistant/help/qoptionswidget_p.h b/src/assistant/help/qoptionswidget_p.h
index d22ab0878..5d48b1ca0 100644
--- a/src/assistant/help/qoptionswidget_p.h
+++ b/src/assistant/help/qoptionswidget_p.h
@@ -58,4 +58,4 @@ private:
 
 QT_END_NAMESPACE
 
-#endif  // OPTIONSWIDGET_H
+#endif // QOPTIONSWIDGET_H
diff --git a/src/designer/src/lib/shared/widgetfactory_p.h b/src/designer/src/lib/shared/widgetfactory_p.h
index 8d0165eaf..6844ed578 100644
--- a/src/designer/src/lib/shared/widgetfactory_p.h
+++ b/src/designer/src/lib/shared/widgetfactory_p.h
@@ -1,3 +1,6 @@
+
+
+
 // Copyright (C) 2016 The Qt Company Ltd.
 // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only WITH Qt-GPL-exception-1.0