From f44e04b14ce55d813481fe58714a0d8eb33ff772 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?M=C3=A5rten=20Nordheim?= <marten.nordheim@qt.io>
Date: Mon, 25 Sep 2023 11:50:39 +0200
Subject: [PATCH] QNetworkInfo[NetworkManager]: Avoid creating temporary
 QStrings

Previously we had some inline c-string literals. But since the parameter
for those is const-ref QString it has to actually allocate the storage
and convert the string to UTF-16.

By putting it as a function that returns a QString constructed
with u""_s, we instead create a cheap non-owning QString that just
refers to the string somewhere in memory.

As a drive-by: move other string-literals into functions as well.

Change-Id: I2f2ca5b979cfa772665fa83689837f991b0c656d
Reviewed-by: Marc Mutz <marc.mutz@qt.io>
---
 .../networkmanager/qnetworkmanagerservice.cpp | 41 ++++++++++++++-----
 1 file changed, 31 insertions(+), 10 deletions(-)

diff --git a/src/plugins/networkinformation/networkmanager/qnetworkmanagerservice.cpp b/src/plugins/networkinformation/networkmanager/qnetworkmanagerservice.cpp
index c3b9d3b452..da540dbecc 100644
--- a/src/plugins/networkinformation/networkmanager/qnetworkmanagerservice.cpp
+++ b/src/plugins/networkinformation/networkmanager/qnetworkmanagerservice.cpp
@@ -27,6 +27,25 @@ QT_BEGIN_NAMESPACE
 
 using namespace Qt::StringLiterals;
 
+namespace {
+constexpr QLatin1StringView propertiesChangedKey = "PropertiesChanged"_L1;
+const QString &stateKey()
+{
+    static auto key = u"State"_s;
+    return key;
+}
+const QString &connectivityKey()
+{
+    static auto key = u"Connectivity"_s;
+    return key;
+}
+const QString &primaryConnectionKey()
+{
+    static auto key = u"PrimaryConnection"_s;
+    return key;
+}
+}
+
 QNetworkManagerInterfaceBase::QNetworkManagerInterfaceBase(QObject *parent)
     : QDBusAbstractInterface(NM_DBUS_SERVICE, NM_DBUS_PATH,
                              NM_DBUS_INTERFACE, QDBusConnection::systemBus(), parent)
@@ -60,28 +79,30 @@ QNetworkManagerInterface::QNetworkManagerInterface(QObject *parent)
     propertyMap = propsReply.value();
 
     validDBusConnection = QDBusConnection::systemBus().connect(NM_DBUS_SERVICE, NM_DBUS_PATH,
-            DBUS_PROPERTIES_INTERFACE, "PropertiesChanged"_L1, this,
+            DBUS_PROPERTIES_INTERFACE, propertiesChangedKey, this,
             SLOT(setProperties(QString,QMap<QString,QVariant>,QList<QString>)));
 }
 
 QNetworkManagerInterface::~QNetworkManagerInterface()
 {
     QDBusConnection::systemBus().disconnect(NM_DBUS_SERVICE, NM_DBUS_PATH,
-            DBUS_PROPERTIES_INTERFACE, "PropertiesChanged"_L1, this,
+            DBUS_PROPERTIES_INTERFACE, propertiesChangedKey, this,
             SLOT(setProperties(QString,QMap<QString,QVariant>,QList<QString>)));
 }
 
 QNetworkManagerInterface::NMState QNetworkManagerInterface::state() const
 {
-    if (propertyMap.contains("State"))
-        return static_cast<QNetworkManagerInterface::NMState>(propertyMap.value("State").toUInt());
+    if (propertyMap.contains(stateKey())) {
+        return static_cast<QNetworkManagerInterface::NMState>(propertyMap.value(stateKey())
+                                                                      .toUInt());
+    }
     return QNetworkManagerInterface::NM_STATE_UNKNOWN;
 }
 
 QNetworkManagerInterface::NMConnectivityState QNetworkManagerInterface::connectivityState() const
 {
-    if (propertyMap.contains("Connectivity"))
-        return static_cast<NMConnectivityState>(propertyMap.value("Connectivity").toUInt());
+    if (propertyMap.contains(connectivityKey()))
+        return static_cast<NMConnectivityState>(propertyMap.value(connectivityKey()).toUInt());
     return QNetworkManagerInterface::NM_CONNECTIVITY_UNKNOWN;
 }
 
@@ -104,7 +125,7 @@ static std::optional<QDBusInterface> getPrimaryDevice(const QDBusObjectPath &dev
 
 std::optional<QDBusObjectPath> QNetworkManagerInterface::primaryConnectionDevicePath() const
 {
-    auto it = propertyMap.constFind(u"PrimaryConnection"_s);
+    auto it = propertyMap.constFind(primaryConnectionKey());
     if (it != propertyMap.cend())
         return it->value<QDBusObjectPath>();
     return std::nullopt;
@@ -171,13 +192,13 @@ void QNetworkManagerInterface::setProperties(const QString &interfaceName,
         }
 
         if (valueChanged) {
-            if (i.key() == "State"_L1) {
+            if (i.key() == stateKey()) {
                 quint32 state = i.value().toUInt();
                 Q_EMIT stateChanged(static_cast<NMState>(state));
-            } else if (i.key() == "Connectivity"_L1) {
+            } else if (i.key() == connectivityKey()) {
                 quint32 state = i.value().toUInt();
                 Q_EMIT connectivityChanged(static_cast<NMConnectivityState>(state));
-            } else if (i.key() == "PrimaryConnection"_L1) {
+            } else if (i.key() == primaryConnectionKey()) {
                 const QDBusObjectPath devicePath = i->value<QDBusObjectPath>();
                 Q_EMIT deviceTypeChanged(extractDeviceType(devicePath));
                 Q_EMIT meteredChanged(extractDeviceMetered(devicePath));