Revert QStringView port

QStringView has some bits of API that were only added in 5.15.2, whereas KF
requires 5.15.0.

This reverts commit 1780fb2a237af80ddc1f9cfb70cb892b53b91990.

4 files changed, 48 insertions, 39 deletions

diff --git a/src/core/kconfig.cpp b/src/core/kconfig.cpp
index 8118ea51..cc3700e1 100644
--- a/src/core/kconfig.cpp
+++ b/src/core/kconfig.cpp
@@ -174,21 +174,21 @@ QString KConfigPrivate::expandString(const QString &value)
     int nDollarPos = aValue.indexOf(QLatin1Char('$'));
     while (nDollarPos != -1 && nDollarPos + 1 < aValue.length()) {
         // there is at least one $
-        if (aValue.at(nDollarPos + 1) != QLatin1Char('$')) {
+        if (aValue[nDollarPos + 1] != QLatin1Char('$')) {
             int nEndPos = nDollarPos + 1;
             // the next character is not $
-            QStringView aVarName;
-            if (aValue.at(nEndPos) == QLatin1Char('{')) {
+            QStringRef aVarName;
+            if (aValue[nEndPos] == QLatin1Char('{')) {
                 while ((nEndPos <= aValue.length()) && (aValue[nEndPos] != QLatin1Char('}'))) {
                     ++nEndPos;
                 }
                 ++nEndPos;
-                aVarName = QStringView(aValue).mid(nDollarPos + 2, nEndPos - nDollarPos - 3);
+                aVarName = aValue.midRef(nDollarPos + 2, nEndPos - nDollarPos - 3);
             } else {
                 while (nEndPos < aValue.length() && (aValue[nEndPos].isNumber() || aValue[nEndPos].isLetter() || aValue[nEndPos] == QLatin1Char('_'))) {
                     ++nEndPos;
                 }
-                aVarName = QStringView(aValue).mid(nDollarPos + 1, nEndPos - nDollarPos - 1);
+                aVarName = aValue.midRef(nDollarPos + 1, nEndPos - nDollarPos - 1);
             }
             QString env;
             if (!aVarName.isEmpty()) {
diff --git a/src/gui/kconfigloader.cpp b/src/gui/kconfigloader.cpp
index 940613b8..bc1751f4 100644
--- a/src/gui/kconfigloader.cpp
+++ b/src/gui/kconfigloader.cpp
@@ -49,14 +49,20 @@ bool ConfigLoaderHandler::parse(QIODevice *input)
 
         switch (reader.tokenType()) {
         case QXmlStreamReader::StartElement:
-            startElement(reader.name(), reader.attributes());
+            if (!startElement(reader.name(), reader.attributes())) {
+                return false;
+            }
             break;
         case QXmlStreamReader::EndElement:
-            endElement(reader.name());
+            if (!endElement(reader.name())) {
+                return false;
+            }
             break;
         case QXmlStreamReader::Characters:
             if (!reader.isWhitespace() && !reader.text().trimmed().isEmpty()) {
-                m_cdata.append(reader.text());
+                if (!characters(reader.text())) {
+                    return false;
+                }
             }
             break;
         default:
@@ -71,19 +77,15 @@ bool ConfigLoaderHandler::parse(QIODevice *input)
     return true;
 }
 
-static bool caseInsensitiveCompare(const QStringView a, const QLatin1String b)
-{
-    return a.compare(b, Qt::CaseInsensitive) == 0;
-}
-
-void ConfigLoaderHandler::startElement(const QStringView localName, const QXmlStreamAttributes &attrs)
+bool ConfigLoaderHandler::startElement(const QStringRef &localName, const QXmlStreamAttributes &attrs)
 {
     // qDebug() << "ConfigLoaderHandler::startElement(" << localName << qName;
-    if (caseInsensitiveCompare(localName, QLatin1String("group"))) {
+    const QString tag = localName.toString().toLower();
+    if (tag == QLatin1String("group")) {
         QString group;
         for (const auto &attr : attrs) {
-            const auto name = attr.name();
-            if (caseInsensitiveCompare(name, QLatin1String("name"))) {
+            const QStringRef name = attr.name();
+            if (name.compare(QLatin1String("name"), Qt::CaseInsensitive) == 0) {
                 // qDebug() << "set group to" << attrs.value(i);
                 group = attr.value().toString();
             }
@@ -100,61 +102,71 @@ void ConfigLoaderHandler::startElement(const QStringView localName, const QXmlSt
         if (m_config) {
             m_config->setCurrentGroup(group);
         }
-    } else if (caseInsensitiveCompare(localName, QLatin1String("entry"))) {
+    } else if (tag == QLatin1String("entry")) {
         for (const auto &attr : attrs) {
-            const auto name = attr.name();
-            if (caseInsensitiveCompare(name, QLatin1String("name"))) {
+            const QStringRef name = attr.name();
+            if (name.compare(QLatin1String("name"), Qt::CaseInsensitive) == 0) {
                 m_name = attr.value().trimmed().toString();
-            } else if (caseInsensitiveCompare(name, QLatin1String("type"))) {
+            } else if (name.compare(QLatin1String("type"), Qt::CaseInsensitive) == 0) {
                 m_type = attr.value().toString().toLower();
-            } else if (caseInsensitiveCompare(name, QLatin1String("key"))) {
+            } else if (name.compare(QLatin1String("key"), Qt::CaseInsensitive) == 0) {
                 m_key = attr.value().trimmed().toString();
             }
         }
-    } else if (caseInsensitiveCompare(localName, QLatin1String("choice"))) {
+    } else if (tag == QLatin1String("choice")) {
         m_choice.name.clear();
         m_choice.label.clear();
         m_choice.whatsThis.clear();
         for (const auto &attr : attrs) {
-            const auto name = attr.name();
-            if (caseInsensitiveCompare(name, QLatin1String("name"))) {
+            const QStringRef name = attr.name();
+            if (name.compare(QLatin1String("name"), Qt::CaseInsensitive) == 0) {
                 m_choice.name = attr.value().toString();
             }
         }
         m_inChoice = true;
     }
+
+    return true;
+}
+
+bool ConfigLoaderHandler::characters(const QStringRef &ch)
+{
+    m_cdata.append(ch.toString());
+    return true;
 }
 
-void ConfigLoaderHandler::endElement(const QStringView localName)
+bool ConfigLoaderHandler::endElement(const QStringRef &localName)
 {
     //     qDebug() << "ConfigLoaderHandler::endElement(" << localName << qName;
-    if (caseInsensitiveCompare(localName, QLatin1String("entry"))) {
+    const QStringRef tag = localName;
+    if (tag.compare(QLatin1String("entry"), Qt::CaseInsensitive) == 0) {
         addItem();
         resetState();
-    } else if (caseInsensitiveCompare(localName, QLatin1String("label"))) {
+    } else if (tag.compare(QLatin1String("label"), Qt::CaseInsensitive) == 0) {
         if (m_inChoice) {
             m_choice.label = m_cdata.trimmed();
         } else {
             m_label = m_cdata.trimmed();
         }
-    } else if (caseInsensitiveCompare(localName, QLatin1String("whatsthis"))) {
+    } else if (tag.compare(QLatin1String("whatsthis"), Qt::CaseInsensitive) == 0) {
         if (m_inChoice) {
             m_choice.whatsThis = m_cdata.trimmed();
         } else {
             m_whatsThis = m_cdata.trimmed();
         }
-    } else if (caseInsensitiveCompare(localName, QLatin1String("default"))) {
+    } else if (tag.compare(QLatin1String("default"), Qt::CaseInsensitive) == 0) {
         m_default = m_cdata.trimmed();
-    } else if (caseInsensitiveCompare(localName, QLatin1String("min"))) {
+    } else if (tag.compare(QLatin1String("min"), Qt::CaseInsensitive) == 0) {
         m_min = m_cdata.toInt(&m_haveMin);
-    } else if (caseInsensitiveCompare(localName, QLatin1String("max"))) {
+    } else if (tag.compare(QLatin1String("max"), Qt::CaseInsensitive) == 0) {
         m_max = m_cdata.toInt(&m_haveMax);
-    } else if (caseInsensitiveCompare(localName, QLatin1String("choice"))) {
+    } else if (tag.compare(QLatin1String("choice"), Qt::CaseInsensitive) == 0) {
         m_enumChoices.append(m_choice);
         m_inChoice = false;
     }
 
     m_cdata.clear();
+    return true;
 }
 
 void ConfigLoaderHandler::addItem()
diff --git a/src/gui/kconfigloaderhandler_p.h b/src/gui/kconfigloaderhandler_p.h
index 297e5462..bc199e0e 100644
--- a/src/gui/kconfigloaderhandler_p.h
+++ b/src/gui/kconfigloaderhandler_p.h
@@ -17,8 +17,9 @@ public:
 
     bool parse(QIODevice *input);
 
-    void startElement(const QStringView localName, const QXmlStreamAttributes &attrs);
-    void endElement(const QStringView localName);
+    bool startElement(const QStringRef &localName, const QXmlStreamAttributes &attrs);
+    bool endElement(const QStringRef &localName);
+    bool characters(const QStringRef &ch);
 
 private:
     void addItem();
diff --git a/src/kconf_update/kconfigutils.cpp b/src/kconf_update/kconfigutils.cpp
index 9608f21c..49d5ac3c 100644
--- a/src/kconf_update/kconfigutils.cpp
+++ b/src/kconf_update/kconfigutils.cpp
@@ -89,11 +89,7 @@ QString unescapeString(const QString &src, bool *ok, QString *error)
                 break;
             case L'x': {
                 if (pos + 2 < length) {
-#if QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
-                    char value = QStringView(src).mid(pos + 1, 2).toInt(ok, 16);
-#else
                     char value = src.midRef(pos + 1, 2).toInt(ok, 16);
-#endif
                     if (*ok) {
                         dst += QLatin1Char{value};
                         pos += 2;