QtNetwork: use const (and const APIs) more

For CoW types, prefer const methods to avoid needless detach()ing.

Mark predictNextRequest() as const, because this method
does not modify the object.

Change-Id: Ic94e2b31445ece46ab1423bf5b5f4e66d9a5b6ca
Reviewed-by: Edward Welbourne <edward.welbourne@theqtcompany.com>
Reviewed-by: Olivier Goffart (Woboq GmbH) <ogoffart@woboq.com>

16 files changed, 47 insertions, 47 deletions

diff --git a/src/network/access/qftp.cpp b/src/network/access/qftp.cpp
index 59f18015a5..23ec390ae5 100644
--- a/src/network/access/qftp.cpp
+++ b/src/network/access/qftp.cpp
@@ -542,7 +542,7 @@ static void _q_parseUnixDir(const QStringList &tokens, const QString &userName,
 
     // Resolve permissions
     int permissions = 0;
-    QString p = tokens.at(2);
+    const QString &p = tokens.at(2);
     permissions |= (p[0] == QLatin1Char('r') ? QUrlInfo::ReadOwner : 0);
     permissions |= (p[1] == QLatin1Char('w') ? QUrlInfo::WriteOwner : 0);
     permissions |= (p[2] == QLatin1Char('x') ? QUrlInfo::ExeOwner : 0);
@@ -947,7 +947,7 @@ void QFtpPI::readyRead()
             const int lowerLimit[3] = {1,0,0};
             const int upperLimit[3] = {5,5,9};
             for (int i=0; i<3; i++) {
-                replyCode[i] = line[i].digitValue();
+                replyCode[i] = line.at(i).digitValue();
                 if (replyCode[i]<lowerLimit[i] || replyCode[i]>upperLimit[i]) {
                     // protocol error
                     return;
@@ -1072,7 +1072,7 @@ bool QFtpPI::processReply()
 #endif
             // this error should be reported
         } else {
-            QStringList lst = addrPortPattern.capturedTexts();
+            const QStringList lst = addrPortPattern.capturedTexts();
             QString host = lst[1] + QLatin1Char('.') + lst[2] + QLatin1Char('.') + lst[3] + QLatin1Char('.') + lst[4];
             quint16 port = (lst[5].toUInt() << 8) + lst[6].toUInt();
             waitForDtpToConnect = true;
@@ -1098,7 +1098,7 @@ bool QFtpPI::processReply()
 
     } else if (replyCodeInt == 230) {
         if (currentCmd.startsWith(QLatin1String("USER ")) && pendingCommands.count()>0 &&
-            pendingCommands.first().startsWith(QLatin1String("PASS "))) {
+            pendingCommands.constFirst().startsWith(QLatin1String("PASS "))) {
             // no need to send the PASS -- we are already logged in
             pendingCommands.pop_front();
         }
@@ -1177,7 +1177,7 @@ bool QFtpPI::startNextCmd()
         emit finished(replyText);
         return false;
     }
-    currentCmd = pendingCommands.first();
+    currentCmd = pendingCommands.constFirst();
 
     // PORT and PASV are edited in-place, depending on whether we
     // should try the extended transfer connection commands EPRT and
@@ -2241,7 +2241,7 @@ void QFtpPrivate::_q_startNextCommand()
     Q_Q(QFtp);
     if (pending.isEmpty())
         return;
-    QFtpCommand *c = pending.first();
+    QFtpCommand *c = pending.constFirst();
 
     error = QFtp::NoError;
     errorString = QT_TRANSLATE_NOOP(QFtp, QLatin1String("Unknown error"));
@@ -2253,7 +2253,7 @@ void QFtpPrivate::_q_startNextCommand()
     // Proxy support, replace the Login argument in place, then fall
     // through.
     if (c->command == QFtp::Login && !proxyHost.isEmpty()) {
-        QString loginString = c->rawCmds.first().trimmed();
+        QString loginString = c->rawCmds.constFirst().trimmed();
         loginString += QLatin1Char('@') + host;
         if (port && port != 21)
             loginString += QLatin1Char(':') + QString::number(port);
@@ -2264,8 +2264,8 @@ void QFtpPrivate::_q_startNextCommand()
     if (c->command == QFtp::SetTransferMode) {
         _q_piFinished(QLatin1String("Transfer mode set"));
     } else if (c->command == QFtp::SetProxy) {
-        proxyHost = c->rawCmds[0];
-        proxyPort = c->rawCmds[1].toUInt();
+        proxyHost = c->rawCmds.at(0);
+        proxyPort = c->rawCmds.at(1).toUInt();
         c->rawCmds.clear();
         _q_piFinished(QLatin1String("Proxy set to ") + proxyHost + QLatin1Char(':') + QString::number(proxyPort));
     } else if (c->command == QFtp::ConnectToHost) {
@@ -2274,11 +2274,11 @@ void QFtpPrivate::_q_startNextCommand()
         pi.setProperty("_q_networksession", q->property("_q_networksession"));
 #endif
         if (!proxyHost.isEmpty()) {
-            host = c->rawCmds[0];
-            port = c->rawCmds[1].toUInt();
+            host = c->rawCmds.at(0);
+            port = c->rawCmds.at(1).toUInt();
             pi.connectToHost(proxyHost, proxyPort);
         } else {
-            pi.connectToHost(c->rawCmds[0], c->rawCmds[1].toUInt());
+            pi.connectToHost(c->rawCmds.at(0), c->rawCmds.at(1).toUInt());
         }
     } else {
         if (c->command == QFtp::Put) {
@@ -2313,7 +2313,7 @@ void QFtpPrivate::_q_piFinished(const QString&)
 {
     if (pending.isEmpty())
         return;
-    QFtpCommand *c = pending.first();
+    QFtpCommand *c = pending.constFirst();
 
     if (c->command == QFtp::Close) {
         // The order of in which the slots are called is arbitrary, so
@@ -2348,7 +2348,7 @@ void QFtpPrivate::_q_piError(int errorCode, const QString &text)
         return;
     }
 
-    QFtpCommand *c = pending.first();
+    QFtpCommand *c = pending.constFirst();
 
     // non-fatal errors
     if (c->command == QFtp::Get && pi.currentCommand().startsWith(QLatin1String("SIZE "))) {
diff --git a/src/network/access/qhttpnetworkconnection.cpp b/src/network/access/qhttpnetworkconnection.cpp
index c70d15f8c4..7144734138 100644
--- a/src/network/access/qhttpnetworkconnection.cpp
+++ b/src/network/access/qhttpnetworkconnection.cpp
@@ -691,7 +691,7 @@ bool QHttpNetworkConnectionPrivate::dequeueRequest(QAbstractSocket *socket)
     return false;
 }
 
-QHttpNetworkRequest QHttpNetworkConnectionPrivate::predictNextRequest()
+QHttpNetworkRequest QHttpNetworkConnectionPrivate::predictNextRequest() const
 {
     if (!highPriorityQueue.isEmpty())
         return highPriorityQueue.last().first;
diff --git a/src/network/access/qhttpnetworkconnection_p.h b/src/network/access/qhttpnetworkconnection_p.h
index 3937ef0e87..e05bc1df74 100644
--- a/src/network/access/qhttpnetworkconnection_p.h
+++ b/src/network/access/qhttpnetworkconnection_p.h
@@ -213,7 +213,7 @@ public:
     void requeueRequest(const HttpMessagePair &pair); // e.g. after pipeline broke
     bool dequeueRequest(QAbstractSocket *socket);
     void prepareRequest(HttpMessagePair &request);
-    QHttpNetworkRequest predictNextRequest();
+    QHttpNetworkRequest predictNextRequest() const;
 
     void fillPipeline(QAbstractSocket *socket);
     bool fillPipeline(QList<HttpMessagePair> &queue, QHttpNetworkConnectionChannel &channel);
diff --git a/src/network/kernel/qdnslookup.cpp b/src/network/kernel/qdnslookup.cpp
index d8f8d78a0f..02df00a590 100644
--- a/src/network/kernel/qdnslookup.cpp
+++ b/src/network/kernel/qdnslookup.cpp
@@ -76,11 +76,11 @@ static void qt_qdnsmailexchangerecord_sort(QList<QDnsMailExchangeRecord> &record
 
         // Determine the slice of records with the current preference.
         QList<QDnsMailExchangeRecord> slice;
-        const quint16 slicePreference = records[i].preference();
+        const quint16 slicePreference = records.at(i).preference();
         for (int j = i; j < records.size(); ++j) {
-            if (records[j].preference() != slicePreference)
+            if (records.at(j).preference() != slicePreference)
                 break;
-            slice << records[j];
+            slice << records.at(j);
         }
 
         // Randomize the slice of records.
@@ -119,13 +119,13 @@ static void qt_qdnsservicerecord_sort(QList<QDnsServiceRecord> &records)
 
         // Determine the slice of records with the current priority.
         QList<QDnsServiceRecord> slice;
-        const quint16 slicePriority = records[i].priority();
+        const quint16 slicePriority = records.at(i).priority();
         unsigned int sliceWeight = 0;
         for (int j = i; j < records.size(); ++j) {
-            if (records[j].priority() != slicePriority)
+            if (records.at(j).priority() != slicePriority)
                 break;
-            sliceWeight += records[j].weight();
-            slice << records[j];
+            sliceWeight += records.at(j).weight();
+            slice << records.at(j);
         }
 #ifdef QDNSLOOKUP_DEBUG
         qDebug("qt_qdnsservicerecord_sort() : priority %i (size: %i, total weight: %i)",
@@ -137,15 +137,15 @@ static void qt_qdnsservicerecord_sort(QList<QDnsServiceRecord> &records)
             const unsigned int weightThreshold = qrand() % (sliceWeight + 1);
             unsigned int summedWeight = 0;
             for (int j = 0; j < slice.size(); ++j) {
-                summedWeight += slice[j].weight();
+                summedWeight += slice.at(j).weight();
                 if (summedWeight >= weightThreshold) {
 #ifdef QDNSLOOKUP_DEBUG
                     qDebug("qt_qdnsservicerecord_sort() : adding %s %i (weight: %i)",
-                           qPrintable(slice[j].target()), slice[j].port(),
-                           slice[j].weight());
+                           qPrintable(slice.at(j).target()), slice.at(j).port(),
+                           slice.at(j).weight());
 #endif
                     // Adjust the slice weight and take the current record.
-                    sliceWeight -= slice[j].weight();
+                    sliceWeight -= slice.at(j).weight();
                     records[i++] = slice.takeAt(j);
                     break;
                 }
diff --git a/src/network/kernel/qnetworkproxy.cpp b/src/network/kernel/qnetworkproxy.cpp
index 22400ef9ab..ad78c48fd8 100644
--- a/src/network/kernel/qnetworkproxy.cpp
+++ b/src/network/kernel/qnetworkproxy.cpp
@@ -297,7 +297,7 @@ public:
 
     QNetworkProxy applicationProxy()
     {
-        return proxyForQuery(QNetworkProxyQuery()).first();
+        return proxyForQuery(QNetworkProxyQuery()).constFirst();
     }
 
     QList<QNetworkProxy> proxyForQuery(const QNetworkProxyQuery &query);
diff --git a/src/network/kernel/qnetworkproxy_win.cpp b/src/network/kernel/qnetworkproxy_win.cpp
index 328f6f889b..16c745fdda 100644
--- a/src/network/kernel/qnetworkproxy_win.cpp
+++ b/src/network/kernel/qnetworkproxy_win.cpp
@@ -332,7 +332,7 @@ static QList<QNetworkProxy> parseServerList(const QNetworkProxyQuery &query, con
 
         result << QNetworkProxy(proxyType, entry.mid(server, pos - server), port);
         if (!protocolTag.isEmpty())
-            taggedProxies.insert(protocolTag.toString(), result.last());
+            taggedProxies.insert(protocolTag.toString(), result.constLast());
     }
 
     if (checkTags && taggedProxies.contains(requiredTag)) {
diff --git a/src/network/socket/qnativesocketengine_unix.cpp b/src/network/socket/qnativesocketengine_unix.cpp
index 6e6191154e..b3e456be69 100644
--- a/src/network/socket/qnativesocketengine_unix.cpp
+++ b/src/network/socket/qnativesocketengine_unix.cpp
@@ -625,7 +625,7 @@ static bool multicastMembershipHelper(QNativeSocketEnginePrivate *d,
         mreq4.imr_multiaddr.s_addr = htonl(groupAddress.toIPv4Address());
 
         if (interface.isValid()) {
-            QList<QNetworkAddressEntry> addressEntries = interface.addressEntries();
+            const QList<QNetworkAddressEntry> addressEntries = interface.addressEntries();
             if (!addressEntries.isEmpty()) {
                 QHostAddress firstIP = addressEntries.first().ip();
                 mreq4.imr_interface.s_addr = htonl(firstIP.toIPv4Address());
diff --git a/src/network/socket/qnativesocketengine_win.cpp b/src/network/socket/qnativesocketengine_win.cpp
index 648f2bf376..6ff5c884f7 100644
--- a/src/network/socket/qnativesocketengine_win.cpp
+++ b/src/network/socket/qnativesocketengine_win.cpp
@@ -936,7 +936,7 @@ static bool multicastMembershipHelper(QNativeSocketEnginePrivate *d,
         mreq4.imr_multiaddr.s_addr = htonl(groupAddress.toIPv4Address());
 
         if (iface.isValid()) {
-            QList<QNetworkAddressEntry> addressEntries = iface.addressEntries();
+            const QList<QNetworkAddressEntry> addressEntries = iface.addressEntries();
             if (!addressEntries.isEmpty()) {
                 QHostAddress firstIP = addressEntries.first().ip();
                 mreq4.imr_interface.s_addr = htonl(firstIP.toIPv4Address());
diff --git a/src/network/ssl/qasn1element.cpp b/src/network/ssl/qasn1element.cpp
index 7ac3a4b45d..dc59c41d59 100644
--- a/src/network/ssl/qasn1element.cpp
+++ b/src/network/ssl/qasn1element.cpp
@@ -192,7 +192,7 @@ QAsn1Element QAsn1Element::fromObjectId(const QByteArray &id)
 {
     QAsn1Element elem;
     elem.mType = ObjectIdentifierType;
-    QList<QByteArray> bits = id.split('.');
+    const QList<QByteArray> bits = id.split('.');
     Q_ASSERT(bits.size() > 2);
     elem.mValue += quint8((bits[0].toUInt() * 40 + bits[1].toUInt()));
     for (int i = 2; i < bits.size(); ++i) {
@@ -311,11 +311,11 @@ QByteArray QAsn1Element::toObjectId() const
 {
     QByteArray key;
     if (mType == ObjectIdentifierType && !mValue.isEmpty()) {
-        quint8 b = mValue[0];
+        quint8 b = mValue.at(0);
         key += QByteArray::number(b / 40) + '.' + QByteArray::number (b % 40);
         unsigned int val = 0;
         for (int i = 1; i < mValue.size(); ++i) {
-            b = mValue[i];
+            b = mValue.at(i);
             val = (val << 7) | (b & 0x7f);
             if (!(b & 0x80)) {
                 key += '.' + QByteArray::number(val);
diff --git a/src/network/ssl/qsslcertificate_openssl.cpp b/src/network/ssl/qsslcertificate_openssl.cpp
index a20100505a..28b7eda54a 100644
--- a/src/network/ssl/qsslcertificate_openssl.cpp
+++ b/src/network/ssl/qsslcertificate_openssl.cpp
@@ -507,7 +507,7 @@ QString QSslCertificate::toText() const
 void QSslCertificatePrivate::init(const QByteArray &data, QSsl::EncodingFormat format)
 {
     if (!data.isEmpty()) {
-        QList<QSslCertificate> certs = (format == QSsl::Pem)
+        const QList<QSslCertificate> certs = (format == QSsl::Pem)
             ? certificatesFromPem(data, 1)
             : certificatesFromDer(data, 1);
         if (!certs.isEmpty()) {
diff --git a/src/network/ssl/qsslcertificate_qt.cpp b/src/network/ssl/qsslcertificate_qt.cpp
index d712fe09b3..a351b8ecc7 100644
--- a/src/network/ssl/qsslcertificate_qt.cpp
+++ b/src/network/ssl/qsslcertificate_qt.cpp
@@ -197,7 +197,7 @@ QString QSslCertificate::toText() const
 void QSslCertificatePrivate::init(const QByteArray &data, QSsl::EncodingFormat format)
 {
     if (!data.isEmpty()) {
-        QList<QSslCertificate> certs = (format == QSsl::Pem)
+        const QList<QSslCertificate> certs = (format == QSsl::Pem)
             ? certificatesFromPem(data, 1)
             : certificatesFromDer(data, 1);
         if (!certs.isEmpty()) {
@@ -309,7 +309,7 @@ bool QSslCertificatePrivate::parse(const QByteArray &data)
         if (!elem.read(versionStream) || elem.type() != QAsn1Element::IntegerType)
             return false;
 
-        versionString = QByteArray::number(elem.value()[0] + 1);
+        versionString = QByteArray::number(elem.value().at(0) + 1);
         if (!elem.read(certStream))
             return false;
     } else {
diff --git a/src/network/ssl/qsslkey_qt.cpp b/src/network/ssl/qsslkey_qt.cpp
index 196edb0956..3c5dc830d3 100644
--- a/src/network/ssl/qsslkey_qt.cpp
+++ b/src/network/ssl/qsslkey_qt.cpp
@@ -169,7 +169,7 @@ void QSslKeyPrivate::decodeDer(const QByteArray &der, bool deepClear)
         QDataStream keyStream(elem.value());
         if (!elem.read(keyStream) || elem.type() != QAsn1Element::SequenceType)
             return;
-        QVector<QAsn1Element> infoItems = elem.toVector();
+        const QVector<QAsn1Element> infoItems = elem.toVector();
         if (infoItems.size() < 2 || infoItems[0].type() != QAsn1Element::ObjectIdentifierType)
             return;
         if (algorithm == QSsl::Rsa) {
@@ -189,7 +189,7 @@ void QSslKeyPrivate::decodeDer(const QByteArray &der, bool deepClear)
             if (infoItems[1].type() != QAsn1Element::SequenceType)
                 return;
             // key params
-            QVector<QAsn1Element> params = infoItems[1].toVector();
+            const QVector<QAsn1Element> params = infoItems[1].toVector();
             if (params.isEmpty() || params[0].type() != QAsn1Element::IntegerType)
                 return;
             keyLength = numberOfBits(params[0].value());
@@ -202,7 +202,7 @@ void QSslKeyPrivate::decodeDer(const QByteArray &der, bool deepClear)
         }
 
     } else {
-        QVector<QAsn1Element> items = elem.toVector();
+        const QVector<QAsn1Element> items = elem.toVector();
         if (items.isEmpty())
             return;
 
@@ -249,7 +249,7 @@ void QSslKeyPrivate::decodePem(const QByteArray &pem, const QByteArray &passPhra
     QMap<QByteArray, QByteArray> headers;
     QByteArray data = derFromPem(pem, &headers);
     if (headers.value("Proc-Type") == "4,ENCRYPTED") {
-        QList<QByteArray> dekInfo = headers.value("DEK-Info").split(',');
+        const QList<QByteArray> dekInfo = headers.value("DEK-Info").split(',');
         if (dekInfo.size() != 2) {
             clear(deepClear);
             return;
diff --git a/src/network/ssl/qsslsocket.cpp b/src/network/ssl/qsslsocket.cpp
index 3e7a30aa9f..35dce23601 100644
--- a/src/network/ssl/qsslsocket.cpp
+++ b/src/network/ssl/qsslsocket.cpp
@@ -2526,7 +2526,7 @@ void QSslSocketPrivate::_q_resumeImplementation()
         if (verifyErrorsHaveBeenIgnored()) {
             continueHandshake();
         } else {
-            setErrorAndEmit(QAbstractSocket::SslHandshakeFailedError, sslErrors.first().errorString());
+            setErrorAndEmit(QAbstractSocket::SslHandshakeFailedError, sslErrors.constFirst().errorString());
             plainSocket->disconnectFromHost();
             return;
         }
diff --git a/src/network/ssl/qsslsocket_mac.cpp b/src/network/ssl/qsslsocket_mac.cpp
index 602496d730..c164342166 100644
--- a/src/network/ssl/qsslsocket_mac.cpp
+++ b/src/network/ssl/qsslsocket_mac.cpp
@@ -442,7 +442,7 @@ void QSslSocketPrivate::ensureInitialized()
         SSLGetSupportedCiphers(context, cfCiphers.data(), &numCiphers);
 
         for (size_t i = 0; i < size_t(cfCiphers.size()); ++i) {
-            const QSslCipher ciph(QSslSocketBackendPrivate::QSslCipher_from_SSLCipherSuite(cfCiphers[i]));
+            const QSslCipher ciph(QSslSocketBackendPrivate::QSslCipher_from_SSLCipherSuite(cfCiphers.at(i)));
             if (!ciph.isNull()) {
                 ciphers << ciph;
                 if (ciph.usedBits() >= 128)
@@ -1033,7 +1033,7 @@ bool QSslSocketBackendPrivate::setSessionCertificate(QString &errorDescription,
 
     QSslCertificate localCertificate;
     if (!configuration.localCertificateChain.isEmpty())
-        localCertificate = configuration.localCertificateChain[0];
+        localCertificate = configuration.localCertificateChain.at(0);
 
     if (!localCertificate.isNull()) {
         // Require a private key as well.
@@ -1327,7 +1327,7 @@ bool QSslSocketBackendPrivate::checkSslErrors()
             paused = true;
         } else {
             setErrorAndEmit(QAbstractSocket::SslHandshakeFailedError,
-                            sslErrors.first().errorString());
+                            sslErrors.constFirst().errorString());
             plainSocket->disconnectFromHost();
         }
         return false;
diff --git a/src/network/ssl/qsslsocket_openssl.cpp b/src/network/ssl/qsslsocket_openssl.cpp
index 35bdd1c87d..67b4550607 100644
--- a/src/network/ssl/qsslsocket_openssl.cpp
+++ b/src/network/ssl/qsslsocket_openssl.cpp
@@ -1234,7 +1234,7 @@ bool QSslSocketBackendPrivate::checkSslErrors()
             pauseSocketNotifiers(q);
             paused = true;
         } else {
-            setErrorAndEmit(QAbstractSocket::SslHandshakeFailedError, sslErrors.first().errorString());
+            setErrorAndEmit(QAbstractSocket::SslHandshakeFailedError, sslErrors.constFirst().errorString());
             plainSocket->disconnectFromHost();
         }
         return false;
diff --git a/src/network/ssl/qsslsocket_winrt.cpp b/src/network/ssl/qsslsocket_winrt.cpp
index 6694e64abc..edc8ca0bbb 100644
--- a/src/network/ssl/qsslsocket_winrt.cpp
+++ b/src/network/ssl/qsslsocket_winrt.cpp
@@ -626,7 +626,7 @@ HRESULT QSslSocketBackendPrivate::onSslUpgrade(IAsyncAction *action, AsyncStatus
 
     if (!sslErrors.isEmpty()) {
         emit q->sslErrors(sslErrors);
-        setErrorAndEmit(QAbstractSocket::SslHandshakeFailedError, sslErrors.first().errorString());
+        setErrorAndEmit(QAbstractSocket::SslHandshakeFailedError, sslErrors.constFirst().errorString());
 
         // Disconnect if there are any non-ignorable errors
         for (const QSslError &error : qAsConst(sslErrors)) {