Simple Cleanups

- use Q_NULLPTR instead of 0 or NULL
- simplify some foreach loops
- use QStringLiteral in a few places
- added a few consts

REVIEW: 118666

18 files changed, 99 insertions, 107 deletions

diff --git a/src/core/bufferfragment_p.h b/src/core/bufferfragment_p.h
index 8d0931bc..e2154a59 100644
--- a/src/core/bufferfragment_p.h
+++ b/src/core/bufferfragment_p.h
@@ -40,7 +40,7 @@ class KConfigIniBackend::BufferFragment
 
 public:
 
-    BufferFragment() : d(0), len(0)
+    BufferFragment() : d(Q_NULLPTR), len(0)
     {
     }
 
@@ -103,7 +103,7 @@ public:
 
     bool isEmpty() const
     {
-        return (len == 0);
+        return !len;
     }
 
     BufferFragment left(unsigned int size) const
@@ -127,7 +127,7 @@ public:
 
     bool isNull() const
     {
-        return (d == 0);
+        return !d;
     }
 
     BufferFragment mid(unsigned int pos, int length = -1) const
diff --git a/src/core/kconfig.cpp b/src/core/kconfig.cpp
index ea9746c0..89e92333 100644
--- a/src/core/kconfig.cpp
+++ b/src/core/kconfig.cpp
@@ -56,7 +56,7 @@ bool KConfigPrivate::mappingsRegistered = false;
 
 KConfigPrivate::KConfigPrivate(KConfig::OpenFlags flags,
                                QStandardPaths::StandardLocation resourceType)
-    : openFlags(flags), resourceType(resourceType), mBackend(0),
+    : openFlags(flags), resourceType(resourceType), mBackend(Q_NULLPTR),
       bDynamicBackend(true),  bDirty(false), bReadDefaults(false),
       bFileImmutable(false), bForceGlobal(false), bSuppressGlobal(false),
       configState(KConfigBase::NoAccess)
diff --git a/src/core/kconfig.h b/src/core/kconfig.h
index d27eebe7..d7d4b7df 100644
--- a/src/core/kconfig.h
+++ b/src/core/kconfig.h
@@ -210,7 +210,7 @@ public:
      *
      * @return @p config if it was set, otherwise a new KConfig object
      */
-    KConfig *copyTo(const QString &file, KConfig *config = 0) const;
+    KConfig *copyTo(const QString &file, KConfig *config = Q_NULLPTR) const;
 
     /**
      * Ensures that the configuration file contains a certain update.
diff --git a/src/core/kconfigbackend.cpp b/src/core/kconfigbackend.cpp
index 90655fac..bf2bc9c7 100644
--- a/src/core/kconfigbackend.cpp
+++ b/src/core/kconfigbackend.cpp
@@ -56,7 +56,7 @@ BackendPtr KConfigBackend::create(const QString &file, const QString &sys)
 {
     //qDebug() << "creating a backend for file" << file << "with system" << sys;
     const QString system = (sys.isEmpty() ? Private::whatSystem(file) : sys);
-    KConfigBackend *backend = 0;
+    KConfigBackend *backend = Q_NULLPTR;
 
 #if 0 // TODO port to Qt5 plugin loading
     if (system.compare(QLatin1String("INI"), Qt::CaseInsensitive) != 0) {
@@ -65,7 +65,7 @@ BackendPtr KConfigBackend::create(const QString &file, const QString &sys)
 
         //qDebug() << "found" << offers.count() << "offers for KConfigBackend plugins with name" << system;
         foreach (const KService::Ptr &offer, offers) {
-            backend = offer->createInstance<KConfigBackend>(0);
+            backend = offer->createInstance<KConfigBackend>(Q_NULLPTR);
             if (backend) {
                 //qDebug() << "successfully created a backend for" << system;
                 backend->setFilePath(file);
diff --git a/src/core/kconfigdata.h b/src/core/kconfigdata.h
index e57becb2..fdec85dc 100644
--- a/src/core/kconfigdata.h
+++ b/src/core/kconfigdata.h
@@ -194,7 +194,7 @@ public:
     QString getEntry(const QByteArray &group, const QByteArray &key,
                      const QString &defaultValue = QString(),
                      SearchFlags flags = SearchFlags(),
-                     bool *expand = 0) const;
+                     bool *expand = Q_NULLPTR) const;
 
     bool hasEntry(const QByteArray &group, const QByteArray &key = QByteArray(),
                   SearchFlags flags = SearchFlags()) const;
diff --git a/src/core/kconfiggroup.cpp b/src/core/kconfiggroup.cpp
index 6f609bae..1ad79f8c 100644
--- a/src/core/kconfiggroup.cpp
+++ b/src/core/kconfiggroup.cpp
@@ -202,7 +202,7 @@ static QList<qreal> asRealList(const QByteArray &string)
 
 static QString errString(const char *pKey, const QByteArray &value, const QVariant &aDefault)
 {
-    return QString::fromLatin1("\"%1\" - conversion of \"%3\" to %2 failed")
+    return QStringLiteral("\"%1\" - conversion of \"%3\" to %2 failed")
            .arg(QString::fromLatin1(pKey))
            .arg(QString::fromLatin1(QVariant::typeToName(aDefault.type())))
            .arg(QString::fromLatin1(value));
@@ -210,7 +210,7 @@ static QString errString(const char *pKey, const QByteArray &value, const QVaria
 
 static QString formatError(int expected, int got)
 {
-    return QString::fromLatin1(" (wrong format: expected %1 items, got %2)").arg(expected).arg(got);
+    return QStringLiteral(" (wrong format: expected %1 items, got %2)").arg(expected).arg(got);
 }
 
 QVariant KConfigGroup::convertToQVariant(const char *pKey, const QByteArray &value, const QVariant &aDefault)
@@ -400,11 +400,11 @@ static bool cleanHomeDirPath(QString &path, const QString &homeDir)
     int len = homeDir.length();
     // replace by "$HOME" if possible
     if (len && (path.length() == len || path[len] == QLatin1Char('/'))) {
-        path.replace(0, len, QString::fromLatin1("$HOME"));
+        path.replace(0, len, QStringLiteral("$HOME"));
         return true;
-    } else {
-        return false;
     }
+
+    return false;
 }
 
 static QString translatePath(QString path)   // krazy:exclude=passbyvalue
@@ -448,19 +448,19 @@ static QString translatePath(QString path)   // krazy:exclude=passbyvalue
     }
 
     if (startsWithFile) {
-        path.prepend(QString::fromLatin1("file://"));
+        path.prepend(QStringLiteral("file://"));
     }
 
     return path;
 }
 
-KConfigGroup::KConfigGroup() : d(0)
+KConfigGroup::KConfigGroup() : d()
 {
 }
 
 bool KConfigGroup::isValid() const
 {
-    return 0 != d.constData();
+    return bool(d);
 }
 
 KConfigGroupGui _kde_internal_KConfigGroupGui;
@@ -519,13 +519,13 @@ KConfigGroup &KConfigGroup::operator=(const KConfigGroup &rhs)
 }
 
 KConfigGroup::KConfigGroup(const KConfigGroup &rhs)
-    : KConfigBase(), d(rhs.d)
+    : d(rhs.d)
 {
 }
 
 KConfigGroup::~KConfigGroup()
 {
-    d = 0;
+    d.reset();
 }
 
 KConfigGroup KConfigGroup::groupImpl(const QByteArray &aGroup)
@@ -1094,7 +1094,7 @@ void KConfigGroup::writeXdgListEntry(const char *key, const QStringList &list, W
     const QStringList::ConstIterator end = list.constEnd();
     for (; it != end; ++it) {
         QString val(*it);
-        val.replace(QLatin1Char('\\'), QLatin1String("\\\\")).replace(QLatin1Char(';'), QLatin1String("\\;"));
+        val.replace(QLatin1Char('\\'), QStringLiteral("\\\\")).replace(QLatin1Char(';'), QStringLiteral("\\;"));
         value += val;
         value += QLatin1Char(';');
     }
@@ -1254,7 +1254,7 @@ bool KConfigGroup::isGroupImmutableImpl(const QByteArray &b) const
 void KConfigGroup::copyTo(KConfigBase *other, WriteConfigFlags pFlags) const
 {
     Q_ASSERT_X(isValid(), "KConfigGroup::copyTo", "accessing an invalid group");
-    Q_ASSERT(other != 0);
+    Q_ASSERT(other != Q_NULLPTR);
 
     if (KConfigGroup *otherGroup = dynamic_cast<KConfigGroup *>(other)) {
         config()->d_func()->copyGroup(d->fullName(), otherGroup->d->fullName(), otherGroup, pFlags);
@@ -1271,7 +1271,7 @@ void KConfigGroup::reparent(KConfigBase *parent, WriteConfigFlags pFlags)
     Q_ASSERT_X(isValid(), "KConfigGroup::reparent", "accessing an invalid group");
     Q_ASSERT_X(!d->bConst, "KConfigGroup::reparent", "reparenting a read-only group");
     Q_ASSERT_X(!d->bImmutable, "KConfigGroup::reparent", "reparenting an immutable group");
-    Q_ASSERT(parent != 0);
+    Q_ASSERT(parent != Q_NULLPTR);
 
     KConfigGroup oldGroup(*this);
 
diff --git a/src/core/kconfiggroup.h b/src/core/kconfiggroup.h
index 3c4bce84..abb246e3 100644
--- a/src/core/kconfiggroup.h
+++ b/src/core/kconfiggroup.h
@@ -88,7 +88,7 @@ public:
     KConfigGroup(const KSharedConfigPtr &master, const char *group);
 
     /**
-     * Creates a read-only copy of a read-only group.
+     * Creates a copy of a group.
      */
     KConfigGroup(const KConfigGroup &);
     KConfigGroup &operator=(const KConfigGroup &);
@@ -280,9 +280,9 @@ public:
     QString readEntry(const char *key, const QString &aDefault) const;
 
     /** Overload for readEntry(const QString&, const QString&) */
-    QString readEntry(const QString &key, const char *aDefault = 0) const;
+    QString readEntry(const QString &key, const char *aDefault = Q_NULLPTR) const;
     /** Overload for readEntry(const QString&, const QString&) */
-    QString readEntry(const char *key, const char *aDefault = 0) const;
+    QString readEntry(const char *key, const char *aDefault = Q_NULLPTR) const;
 
     /**
      * @copydoc readEntry(const char*, const QStringList&) const
diff --git a/src/core/kconfigini.cpp b/src/core/kconfigini.cpp
index df834f57..a882ee31 100644
--- a/src/core/kconfigini.cpp
+++ b/src/core/kconfigini.cpp
@@ -51,7 +51,7 @@ QString KConfigIniBackend::warningProlog(const QFile &file, int line)
 }
 
 KConfigIniBackend::KConfigIniBackend()
-    : KConfigBackend(), lockFile(NULL)
+    : KConfigBackend(), lockFile(Q_NULLPTR)
 {
 }
 
@@ -617,7 +617,7 @@ void KConfigIniBackend::unlock()
 {
     lockFile->unlock();
     delete lockFile;
-    lockFile = NULL;
+    lockFile = Q_NULLPTR;
 }
 
 bool KConfigIniBackend::isLocked() const
diff --git a/src/core/kcoreconfigskeleton.h b/src/core/kcoreconfigskeleton.h
index bb9c1cf9..f8313d1e 100644
--- a/src/core/kcoreconfigskeleton.h
+++ b/src/core/kcoreconfigskeleton.h
@@ -526,7 +526,7 @@ public:
     public:
         /** @copydoc KConfigSkeletonGenericItem::KConfigSkeletonGenericItem */
         ItemProperty(const QString &_group, const QString &_key,
-                     QVariant &reference, const QVariant &defaultValue = 0);
+                     QVariant &reference, const QVariant &defaultValue = QVariant());
 
         void readConfig(KConfig *config);
         void setProperty(const QVariant &p);
@@ -1004,7 +1004,7 @@ public:
      *                   config file as returned by KSharedConfig::openConfig() is used
      * @param parent the parent object (see QObject documentation)
      */
-    explicit KCoreConfigSkeleton(const QString &configname = QString(), QObject *parent = 0);
+    explicit KCoreConfigSkeleton(const QString &configname = QString(), QObject *parent = Q_NULLPTR);
 
     /**
      * Constructor.
@@ -1012,7 +1012,7 @@ public:
      * @param config configuration object to use
      * @param parent the parent object (see QObject documentation)
      */
-    explicit KCoreConfigSkeleton(KSharedConfig::Ptr config, QObject *parent = 0);
+    explicit KCoreConfigSkeleton(KSharedConfig::Ptr config, QObject *parent = Q_NULLPTR);
 
     /**
      * Destructor
diff --git a/src/core/kemailsettings.cpp b/src/core/kemailsettings.cpp
index 230c2aa4..59d5f6e3 100644
--- a/src/core/kemailsettings.cpp
+++ b/src/core/kemailsettings.cpp
@@ -32,7 +32,7 @@
 class KEMailSettingsPrivate
 {
 public:
-    KEMailSettingsPrivate() : m_pConfig(0) {}
+    KEMailSettingsPrivate() : m_pConfig(Q_NULLPTR) {}
     ~KEMailSettingsPrivate()
     {
         delete m_pConfig;
diff --git a/src/core/ksharedconfig.cpp b/src/core/ksharedconfig.cpp
index 34947065..f4b4c766 100644
--- a/src/core/ksharedconfig.cpp
+++ b/src/core/ksharedconfig.cpp
@@ -72,13 +72,13 @@ KSharedConfigPtr KSharedConfig::openConfig(const QString &_fileName,
     }
 
     if (list) {
-        for (QList<KSharedConfig *>::ConstIterator it = list->constBegin(); it != list->constEnd(); ++it) {
-            if ((*it)->name() == fileName &&
-                    (*it)->d_ptr->openFlags == flags &&
-                    (*it)->locationType() == resType
-//                 (*it)->backEnd()->type() == backEnd
+        foreach (auto cfg, *static_cast<const GlobalSharedConfigList*>(list)) {
+            if (cfg->name() == fileName &&
+                    cfg->d_ptr->openFlags == flags &&
+                    cfg->locationType() == resType
+//                    cfg->backend()->type() == backend
                ) {
-                return KSharedConfigPtr(*it);
+                return KSharedConfigPtr(cfg);
             }
         }
     }
diff --git a/src/gui/kconfiggroupgui.cpp b/src/gui/kconfiggroupgui.cpp
index a14c204c..e2eb950f 100644
--- a/src/gui/kconfiggroupgui.cpp
+++ b/src/gui/kconfiggroupgui.cpp
@@ -38,11 +38,11 @@
 static bool readEntryGui(const QByteArray &data, const char *key, const QVariant &input,
                          QVariant &output)
 {
-    const QString errString = QString::fromLatin1("\"%1\" - conversion from \"%3\" to %2 failed")
+    const QString errString = QStringLiteral("\"%1\" - conversion from \"%3\" to %2 failed")
                               .arg(QLatin1String(key))
                               .arg(QLatin1String(QVariant::typeToName(input.type())))
                               .arg(QLatin1String(data.constData()));
-    const QString formatError = QString::fromLatin1(" (wrong format: expected '%1' items, read '%2')");
+    const QString formatError = QStringLiteral(" (wrong format: expected '%1' items, read '%2')");
 
     // set in case of failure
     output = input;
@@ -70,7 +70,7 @@ static bool readEntryGui(const QByteArray &data, const char *key, const QVariant
             const int count = list.count();
 
             if (count != 3 && count != 4) {
-                qCritical() << qPrintable(errString) << qPrintable(formatError.arg(QLatin1String("3' or '4")).arg(count));
+                qCritical() << qPrintable(errString) << qPrintable(formatError.arg(QStringLiteral("3' or '4")).arg(count));
                 return true;    // return default
             }
 
@@ -84,12 +84,12 @@ static bool readEntryGui(const QByteArray &data, const char *key, const QVariant
                     return true; // return default
                 }
                 if (j < 0 || j > 255) {
-                    static const char *const components[6] = {
+                    static const char *const components[] = {
                         "red", "green", "blue", "alpha"
                     };
-                    const QString boundsError = QLatin1String(" (bounds error: %1 component %2)");
+                    const QString boundsError = QStringLiteral(" (bounds error: %1 component %2)");
                     qCritical() << qPrintable(errString)
-                                << qPrintable(boundsError.arg(QLatin1String(components[i])).arg(j < 0 ? QLatin1String("< 0") : QLatin1String("> 255")));
+                                << qPrintable(boundsError.arg(QLatin1String(components[i])).arg(j < 0 ? QStringLiteral("< 0") : QStringLiteral("> 255")));
                     return true; // return default
                 }
             }
diff --git a/src/gui/kconfiggui.cpp b/src/gui/kconfiggui.cpp
index 1eee8ce5..0048c60a 100644
--- a/src/gui/kconfiggui.cpp
+++ b/src/gui/kconfiggui.cpp
@@ -25,7 +25,7 @@
 
 #include <kconfig.h>
 
-static KConfig *s_sessionConfig = 0;
+static KConfig *s_sessionConfig = Q_NULLPTR;
 
 KConfig *KConfigGui::sessionConfig()
 {
@@ -37,7 +37,7 @@ KConfig *KConfigGui::sessionConfig()
 
 bool KConfigGui::hasSessionConfig()
 {
-    return s_sessionConfig != 0;
+    return s_sessionConfig != Q_NULLPTR;
 }
 
 QString KConfigGui::sessionConfigName()
diff --git a/src/gui/kconfigloader.cpp b/src/gui/kconfigloader.cpp
index 1dd9e7fc..52ac6d17 100644
--- a/src/gui/kconfigloader.cpp
+++ b/src/gui/kconfigloader.cpp
@@ -76,7 +76,7 @@ bool ConfigLoaderHandler::startElement(const QString &namespaceURI, const QStrin
         } else {
             d->groups.append(group);
             if (!d->baseGroup.isEmpty()) {
-                group = d->baseGroup + QStringLiteral("\x1d") + group;
+                group = d->baseGroup + QLatin1Char('\x1d') + group;
             }
         }
 
@@ -194,9 +194,9 @@ void ConfigLoaderHandler::addItem()
         m_name = m_key;
     }
 
-    m_name.remove(QStringLiteral(" "));
+    m_name.remove(QLatin1Char(' '));
 
-    KConfigSkeletonItem *item = 0;
+    KConfigSkeletonItem *item = Q_NULLPTR;
 
     if (m_type == QStringLiteral("bool")) {
         bool defaultValue = m_default.toLower() == QStringLiteral("true");
@@ -239,7 +239,7 @@ void ConfigLoaderHandler::addItem()
     } else if (m_type == QStringLiteral("stringlist")) {
         //FIXME: the split() is naive and will break on lists with ,'s in them
         item = m_config->addItemStringList(m_name, *d->newStringList(),
-                                           m_default.split(QStringLiteral(",")), m_key);
+                                           m_default.split(QLatin1Char(',')), m_key);
     } else if (m_type == QStringLiteral("uint")) {
         KConfigSkeleton::ItemUInt *uintItem =
             m_config->addItemUInt(m_name, *d->newUint(), m_default.toUInt(), m_key);
@@ -269,7 +269,7 @@ void ConfigLoaderHandler::addItem()
         }
         item = doubleItem;
     } else if (m_type == QStringLiteral("intlist")) {
-        QStringList tmpList = m_default.split(QStringLiteral(","));
+        QStringList tmpList = m_default.split(QLatin1Char(','));
         QList<int> defaultList;
         foreach (const QString &tmp, tmpList) {
             defaultList.append(tmp.toInt());
@@ -292,7 +292,7 @@ void ConfigLoaderHandler::addItem()
         */
     } else if (m_type == QStringLiteral("point")) {
         QPoint defaultPoint;
-        QStringList tmpList = m_default.split(QStringLiteral(","));
+        QStringList tmpList = m_default.split(QLatin1Char(','));
         if (tmpList.size() >= 2) {
             defaultPoint.setX(tmpList[0].toInt());
             defaultPoint.setY(tmpList[1].toInt());
@@ -300,7 +300,7 @@ void ConfigLoaderHandler::addItem()
         item = m_config->addItemPoint(m_name, *d->newPoint(), defaultPoint, m_key);
     } else if (m_type == QStringLiteral("rect")) {
         QRect defaultRect;
-        QStringList tmpList = m_default.split(QStringLiteral(","));
+        QStringList tmpList = m_default.split(QLatin1Char(','));
         if (tmpList.size() >= 4) {
             defaultRect.setCoords(tmpList[0].toInt(), tmpList[1].toInt(),
                                   tmpList[2].toInt(), tmpList[3].toInt());
@@ -308,7 +308,7 @@ void ConfigLoaderHandler::addItem()
         item = m_config->addItemRect(m_name, *d->newRect(), defaultRect, m_key);
     } else if (m_type == QStringLiteral("size")) {
         QSize defaultSize;
-        QStringList tmpList = m_default.split(QStringLiteral(","));
+        QStringList tmpList = m_default.split(QLatin1Char(','));
         if (tmpList.size() >= 2) {
             defaultSize.setWidth(tmpList[0].toInt());
             defaultSize.setHeight(tmpList[1].toInt());
@@ -382,7 +382,7 @@ KConfigLoader::KConfigLoader(const KConfigGroup &config, QIODevice *xml, QObject
     KConfigGroup group = config.parent();
     d->baseGroup = config.name();
     while (group.isValid() && group.name() != QStringLiteral("<default>")) {
-        d->baseGroup = group.name() + QStringLiteral("\x1d") + d->baseGroup;
+        d->baseGroup = group.name() + QLatin1Char('\x1d') + d->baseGroup;
         group = group.parent();
     }
     d->parse(this, xml);
@@ -427,10 +427,8 @@ QStringList KConfigLoader::groupList() const
 bool KConfigLoader::usrWriteConfig()
 {
     if (d->saveDefaults) {
-        KConfigSkeletonItem::List itemList = items();
-        for (int i = 0; i < itemList.size(); i++) {
-            KConfigGroup cg(config(), itemList.at(i)->group());
-            cg.writeEntry(itemList.at(i)->key(), "");
+        foreach (const auto& item, items()) {
+            config()->group(item->group()).writeEntry(item->key(), "");
         }
     }
     return true;
diff --git a/src/gui/kconfigloader.h b/src/gui/kconfigloader.h
index 36eb182f..0fb51421 100644
--- a/src/gui/kconfigloader.h
+++ b/src/gui/kconfigloader.h
@@ -107,7 +107,7 @@ public:
      * @param xml the xml data; must be valid KConfigXT data
      * @param parent optional QObject parent
      **/
-    KConfigLoader(const QString &configFile, QIODevice *xml, QObject *parent = 0);
+    KConfigLoader(const QString &configFile, QIODevice *xml, QObject *parent = Q_NULLPTR);
 
     /**
      * Creates a KConfigSkeleton populated using the definition found in
@@ -117,7 +117,7 @@ public:
      * @param xml the xml data; must be valid KConfigXT data
      * @param parent optional QObject parent
      **/
-    KConfigLoader(KSharedConfigPtr config, QIODevice *xml, QObject *parent = 0);
+    KConfigLoader(KSharedConfigPtr config, QIODevice *xml, QObject *parent = Q_NULLPTR);
 
     /**
      * Creates a KConfigSkeleton populated using the definition found in
@@ -127,7 +127,7 @@ public:
      * @param xml the xml data; must be valid KConfigXT data
      * @param parent optional QObject parent
      **/
-    KConfigLoader(const KConfigGroup &config, QIODevice *xml, QObject *parent = 0);
+    KConfigLoader(const KConfigGroup &config, QIODevice *xml, QObject *parent = Q_NULLPTR);
 
     ~KConfigLoader();
 
diff --git a/src/gui/kconfigskeleton.h b/src/gui/kconfigskeleton.h
index f87eef6e..4cd8d140 100644
--- a/src/gui/kconfigskeleton.h
+++ b/src/gui/kconfigskeleton.h
@@ -95,14 +95,14 @@ public:
      * @param configname name of config file. If no name is given, the default
      * config file as returned by KSharedConfig::openConfig() is used.
      */
-    explicit KConfigSkeleton(const QString &configname = QString(), QObject *parent = 0);
+    explicit KConfigSkeleton(const QString &configname = QString(), QObject *parent = Q_NULLPTR);
 
     /**
      * Constructor.
      *
      * @param config configuration object to use.
      */
-    explicit KConfigSkeleton(KSharedConfig::Ptr config, QObject *parent = 0);
+    explicit KConfigSkeleton(KSharedConfig::Ptr config, QObject *parent = Q_NULLPTR);
 
     /**
      * Register an item of type QColor.
diff --git a/src/kconf_update/kconf_update.cpp b/src/kconf_update/kconf_update.cpp
index 829d35e6..255a382e 100644
--- a/src/kconf_update/kconf_update.cpp
+++ b/src/kconf_update/kconf_update.cpp
@@ -104,12 +104,10 @@ protected:
 };
 
 KonfUpdate::KonfUpdate(QCommandLineParser *parser)
-    : m_textStream(0), m_file(0)
+    : m_oldConfig1(Q_NULLPTR), m_oldConfig2(Q_NULLPTR), m_newConfig(Q_NULLPTR),
+      m_textStream(Q_NULLPTR), m_file(Q_NULLPTR)
 {
     bool updateAll = false;
-    m_oldConfig1 = 0;
-    m_oldConfig2 = 0;
-    m_newConfig = 0;
 
     m_config = new KConfig("kconf_updaterc");
     KConfigGroup cg(m_config, QString());
@@ -121,7 +119,7 @@ KonfUpdate::KonfUpdate(QCommandLineParser *parser)
     m_bUseConfigInfo = false;
     if (parser->isSet("check")) {
         m_bUseConfigInfo = true;
-        QString file = QStandardPaths::locate(QStandardPaths::GenericDataLocation, "kconf_update/" + parser->value("check"));
+        const QString file = QStandardPaths::locate(QStandardPaths::GenericDataLocation, "kconf_update/" + parser->value("check"));
         if (file.isEmpty()) {
             qWarning("File '%s' not found.", parser->value("check").toLocal8Bit().data());
             log() << "File '" << parser->value("check") << "' passed on command line not found" << endl;
@@ -138,10 +136,8 @@ KonfUpdate::KonfUpdate(QCommandLineParser *parser)
         updateAll = true;
     }
 
-    for (QStringList::ConstIterator it = updateFiles.constBegin();
-            it != updateFiles.constEnd();
-            ++it) {
-        updateFile(*it);
+    foreach (const QString& file, updateFiles) {
+        updateFile(file);
     }
 
     if (updateAll && !cg.readEntry("updateInfoAdded", false)) {
@@ -205,15 +201,17 @@ QStringList KonfUpdate::findUpdateFiles(bool dirtyOnly)
     QStringList result;
 
     const QStringList dirs = QStandardPaths::locateAll(QStandardPaths::GenericDataLocation, "kconf_update", QStandardPaths::LocateDirectory);
-    Q_FOREACH (const QString &dir, dirs) {
-        const QStringList fileNames = QDir(dir).entryList(QStringList() << QStringLiteral("*.upd"));
+    Q_FOREACH (const QString &d, dirs) {
+        const QDir dir(d);
+
+        const QStringList fileNames = dir.entryList(QStringList(QStringLiteral("*.upd")));
         Q_FOREACH (const QString &fileName, fileNames) {
-            const QString file = dir + '/' + fileName;
+            const QString file = dir.filePath(fileName);
             QFileInfo info(file);
 
             KConfigGroup cg(m_config, fileName);
-            const QDateTime ctime = QDateTime::fromTime_t(cg.readEntry("ctime", 0));
-            const QDateTime mtime = QDateTime::fromTime_t(cg.readEntry("mtime", 0));
+            const QDateTime ctime = QDateTime::fromTime_t(cg.readEntry("ctime", 0u));
+            const QDateTime mtime = QDateTime::fromTime_t(cg.readEntry("mtime", 0u));
             if (!dirtyOnly ||
                     (ctime != info.created()) || (mtime != info.lastModified())) {
                 result.append(file);
@@ -242,7 +240,7 @@ bool KonfUpdate::checkFile(const QString &filename)
     resetOptions();
     QString id;
     while (!ts.atEnd()) {
-        QString line = ts.readLine().trimmed();
+        const QString line = ts.readLine().trimmed();
         lineCount++;
         if (line.isEmpty() || (line[0] == '#')) {
             continue;
@@ -270,7 +268,7 @@ void KonfUpdate::checkGotFile(const QString &_file, const QString &id)
 //   qDebug("File %s, id %s", file.toLatin1().constData(), id.toLatin1().constData());
 
     KConfig cfg(file, KConfig::SimpleConfig);
-    KConfigGroup cg(&cfg, "$Version");
+    KConfigGroup cg = cfg.group("$Version");
     QStringList ids = cg.readEntry("update_info", QStringList());
     if (ids.contains(id)) {
         return;
@@ -320,7 +318,7 @@ bool KonfUpdate::updateFile(const QString &filename)
     while (!ts.atEnd()) {
         m_line = ts.readLine().trimmed();
         m_lineCount++;
-        if (m_line.isEmpty() || (m_line[0] == '#')) {
+        if (m_line.isEmpty() || (m_line[0] == QLatin1Char('#'))) {
             continue;
         }
         if (m_line.startsWith(QLatin1String("Id="))) {
@@ -349,10 +347,10 @@ bool KonfUpdate::updateFile(const QString &filename)
         } else if (m_line.startsWith(QLatin1String("RemoveKey="))) {
             gotRemoveKey(m_line.mid(10));
             resetOptions();
-        } else if (m_line == "AllKeys") {
+        } else if (m_line == QLatin1String("AllKeys")) {
             gotAllKeys();
             resetOptions();
-        } else if (m_line == "AllGroups") {
+        } else if (m_line == QLatin1String("AllGroups")) {
             gotAllGroups();
             resetOptions();
         } else {
@@ -415,7 +413,7 @@ void KonfUpdate::gotFile(const QString &_file)
     if (!m_oldFile.isEmpty()) {
         // Close old file.
         delete m_oldConfig1;
-        m_oldConfig1 = 0;
+        m_oldConfig1 = Q_NULLPTR;
 
         KConfigGroup cg(m_oldConfig2, "$Version");
         QStringList ids = cg.readEntry("update_info", QStringList());
@@ -426,7 +424,7 @@ void KonfUpdate::gotFile(const QString &_file)
         }
         cg.sync();
         delete m_oldConfig2;
-        m_oldConfig2 = 0;
+        m_oldConfig2 = Q_NULLPTR;
 
         QString file = QStandardPaths::writableLocation(QStandardPaths::GenericConfigLocation) + QLatin1Char('/') + m_oldFile;
         QFileInfo info(file);
@@ -448,11 +446,11 @@ void KonfUpdate::gotFile(const QString &_file)
         }
         m_newConfig->sync();
         delete m_newConfig;
-        m_newConfig = 0;
+        m_newConfig = Q_NULLPTR;
 
         m_newFile.clear();
     }
-    m_newConfig = 0;
+    m_newConfig = Q_NULLPTR;
 
     int i = _file.indexOf(',');
     if (i == -1) {
@@ -499,7 +497,7 @@ void KonfUpdate::gotFile(const QString &_file)
 
     m_skipFile = false;
     if (!m_oldFile.isEmpty()) { // if File= is specified, it doesn't exist, is empty or contains only kconf_update's [$Version] group, skip
-        if (m_oldConfig1 != NULL
+        if (m_oldConfig1 != Q_NULLPTR
                 && (m_oldConfig1->groupList().isEmpty()
                     || (m_oldConfig1->groupList().count() == 1 && m_oldConfig1->groupList().first() == "$Version"))) {
             log() << m_currentFilename << ": File '" << m_oldFile << "' does not exist or empty, skipping" << endl;
@@ -619,7 +617,7 @@ void KonfUpdate::copyOrMoveGroup(const QStringList &srcGroupPath, const QStringL
 
     // Subgroups
     Q_FOREACH (const QString &group, cg.groupList()) {
-        QStringList groupPath = QStringList() << group;
+        const QStringList groupPath(group);
         copyOrMoveGroup(srcGroupPath + groupPath, dstGroupPath + groupPath);
     }
 }
@@ -684,11 +682,11 @@ void KonfUpdate::gotOptions(const QString &_options)
     for (QStringList::ConstIterator it = options.begin();
             it != options.end();
             ++it) {
-        if ((*it).toLower().trimmed() == "copy") {
+        if ((*it).toLower().trimmed() == QLatin1String("copy")) {
             m_bCopy = true;
         }
 
-        if ((*it).toLower().trimmed() == "overwrite") {
+        if ((*it).toLower().trimmed() == QLatin1String("overwrite")) {
             m_bOverwrite = true;
         }
     }
@@ -697,9 +695,8 @@ void KonfUpdate::gotOptions(const QString &_options)
 void KonfUpdate::copyGroup(const KConfigBase *cfg1, const QString &group1,
                            KConfigBase *cfg2, const QString &group2)
 {
-    KConfigGroup cg1(cfg1, group1);
-    KConfigGroup cg2(cfg2, group2);
-    copyGroup(cg1, cg2);
+    KConfigGroup cg2 = cfg2->group(group2);
+    copyGroup(cfg1->group(group1), cg2);
 }
 
 void KonfUpdate::copyGroup(const KConfigGroup &cg1, KConfigGroup &cg2)
@@ -741,7 +738,7 @@ void KonfUpdate::gotScript(const QString &_script)
         return;
     }
 
-    QString path = QStandardPaths::locate(QStandardPaths::GenericDataLocation, "kconf_update/" + script);
+    QString path = QStandardPaths::locate(QStandardPaths::GenericDataLocation, QStringLiteral("kconf_update/") + script);
     if (path.isEmpty()) {
         if (interpreter.isEmpty()) {
             path = CMAKE_INSTALL_PREFIX "/" LIB_INSTALL_DIR "/kconf_update_bin/" + script;
diff --git a/src/kconf_update/kconfigutils.cpp b/src/kconf_update/kconfigutils.cpp
index f2663e13..0fec63a6 100644
--- a/src/kconf_update/kconfigutils.cpp
+++ b/src/kconf_update/kconfigutils.cpp
@@ -33,16 +33,13 @@ bool hasGroup(KConfig *config, const QStringList &lst)
     return group.exists();
 }
 
-KConfigGroup openGroup(KConfig *config, const QStringList &_lst)
+KConfigGroup openGroup(KConfig *config, const QStringList &lst)
 {
-    if (_lst.isEmpty()) {
-        return KConfigGroup(config, QString());
-    }
-
-    QStringList lst = _lst;
+    KConfigGroup cg = config->group("");
 
-    KConfigGroup cg;
-    for (cg = KConfigGroup(config, lst.takeFirst()); !lst.isEmpty(); cg = KConfigGroup(&cg, lst.takeFirst())) {}
+    foreach (auto i, lst) {
+        cg = cg.group(i);
+    }
     return cg;
 }
 
@@ -61,14 +58,14 @@ QStringList parseGroupString(const QString &_str, bool *ok, QString *error)
 
     if (!str.endsWith(']')) {
         *ok = false;
-        *error = QString("Missing closing ']' in %1").arg(_str);
+        *error = QStringLiteral("Missing closing ']' in %1").arg(_str);
         return QStringList();
     }
     // trim outer brackets
     str.chop(1);
     str.remove(0, 1);
 
-    return str.split("][");
+    return str.split(QStringLiteral("]["));
 }
 
 QString unescapeString(const QString &src, bool *ok, QString *error)
@@ -83,7 +80,7 @@ QString unescapeString(const QString &src, bool *ok, QString *error)
             ++pos;
             if (pos == length) {
                 *ok = false;
-                *error = QString("Unfinished escape sequence in %1").arg(src);
+                *error = QStringLiteral("Unfinished escape sequence in %1").arg(src);
                 return QString();
             }
             ch = src.at(pos);
@@ -104,17 +101,17 @@ QString unescapeString(const QString &src, bool *ok, QString *error)
                         dst += QChar::fromLatin1(value);
                         pos += 2;
                     } else {
-                        *error = QString("Invalid hex escape sequence at column %1 in %2").arg(pos).arg(src);
+                        *error = QStringLiteral("Invalid hex escape sequence at column %1 in %2").arg(pos).arg(src);
                         return QString();
                     }
                 } else {
                     *ok = false;
-                    *error = QString("Unfinished hex escape sequence at column %1 in %2").arg(pos).arg(src);
+                    *error = QStringLiteral("Unfinished hex escape sequence at column %1 in %2").arg(pos).arg(src);
                     return QString();
                 }
             } else {
                 *ok = false;
-                *error = QString("Invalid escape sequence at column %1 in %2").arg(pos).arg(src);
+                *error = QStringLiteral("Invalid escape sequence at column %1 in %2").arg(pos).arg(src);
                 return QString();
             }
         }