Use QString::fromLatin1() less to avoid string allocations

QString::fromLatin1 always allocates memory, but there are
cases where we can avoid/reduce allocations or/and reduce
text size, e.g.:

QStringBuilder expressions
Fix: replace QString::fromLatin1 with QL1S

QString::fromLatin1().arg(String) pattern
Fix: replace with QStringBuilder

Overloaded functions with QL1S arg
Fix: replace QString::fromLatin1 with QL1S

In rare cases if there is no overloaded function
with QL1S and we have deal with string literal,
replace QString::fromLatin1 with QStringLiteral.

Change-Id: Iabe1a3cc0830f40ef78a0548afa4368583c31def
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>

3 files changed, 4 insertions, 4 deletions

diff --git a/src/network/access/qhttpnetworkconnection.cpp b/src/network/access/qhttpnetworkconnection.cpp
index 74fc23957c..8e5cfd9497 100644
--- a/src/network/access/qhttpnetworkconnection.cpp
+++ b/src/network/access/qhttpnetworkconnection.cpp
@@ -319,9 +319,9 @@ void QHttpNetworkConnectionPrivate::prepareRequest(HttpMessagePair &messagePair)
         if (systemLocale == QLatin1String("C"))
             acceptLanguage = QString::fromLatin1("en,*");
         else if (systemLocale.startsWith(QLatin1String("en-")))
-            acceptLanguage = QString::fromLatin1("%1,*").arg(systemLocale);
+            acceptLanguage = systemLocale + QLatin1String(",*");
         else
-            acceptLanguage = QString::fromLatin1("%1,en,*").arg(systemLocale);
+            acceptLanguage = systemLocale + QLatin1String(",en,*");
         request.setHeaderField("Accept-Language", acceptLanguage.toLatin1());
     }
 
diff --git a/src/network/kernel/qnetworkinterface_unix.cpp b/src/network/kernel/qnetworkinterface_unix.cpp
index da53ccfe70..2fa98c0e07 100644
--- a/src/network/kernel/qnetworkinterface_unix.cpp
+++ b/src/network/kernel/qnetworkinterface_unix.cpp
@@ -488,7 +488,7 @@ static QList<QNetworkInterfacePrivate *> interfaceListing()
     interfaces = createInterfaces(interfaceListing);
     for (ifaddrs *ptr = interfaceListing; ptr; ptr = ptr->ifa_next) {
         // Find the interface
-        QString name = QString::fromLatin1(ptr->ifa_name);
+        QLatin1String name(ptr->ifa_name);
         QNetworkInterfacePrivate *iface = 0;
         QList<QNetworkInterfacePrivate *>::Iterator if_it = interfaces.begin();
         for ( ; if_it != interfaces.end(); ++if_it)
diff --git a/src/network/kernel/qnetworkproxy_generic.cpp b/src/network/kernel/qnetworkproxy_generic.cpp
index e69870a98c..3ff0cc5168 100644
--- a/src/network/kernel/qnetworkproxy_generic.cpp
+++ b/src/network/kernel/qnetworkproxy_generic.cpp
@@ -79,7 +79,7 @@ static bool ignoreProxyFor(const QNetworkProxyQuery &query)
         if (!peerHostName.startsWith('.'))
             peerHostName.prepend('.');
 
-        if (peerHostName.endsWith(QString::fromLatin1(token)))
+        if (peerHostName.endsWith(QLatin1String(token)))
             return true;
     }