Save two system calls for setting a socket non-blocking on Linux

Linux's socket(2) system call can take SOCK_NONBLOCK and let us avoid
the extra two fcntl(2) to change the setting after it's created.

Change-Id: Ie0d7a2d51acc21acd850cbee6d0f76e27b1ae859
Reviewed-by: Richard J. Moore <rich@kde.org>

src/network/socket/qlocalsocket_unix.cpp

@@ -235,19 +235,11 @@ void QLocalSocket::connectToServer(OpenMode openMode)
     }
 
     // create the socket
-    if (-1 == (d->connectingSocket = qt_safe_socket(PF_UNIX, SOCK_STREAM, 0))) {
+    if (-1 == (d->connectingSocket = qt_safe_socket(PF_UNIX, SOCK_STREAM, 0, O_NONBLOCK))) {
         d->errorOccurred(UnsupportedSocketOperationError,
                         QLatin1String("QLocalSocket::connectToServer"));
         return;
     }
-    // set non blocking so we can try to connect and it won't wait
-    int flags = fcntl(d->connectingSocket, F_GETFL, 0);
-    if (-1 == flags
-        || -1 == (fcntl(d->connectingSocket, F_SETFL, flags | O_NONBLOCK))) {
-        d->errorOccurred(UnknownSocketError,
-                QLatin1String("QLocalSocket::connectToServer"));
-        return;
-    }
 
     // _q_connectToSocket does the actual connecting
     d->connectingName = d->serverName;

src/network/socket/qnativesocketengine.cpp

@@ -357,14 +357,6 @@ bool QNativeSocketEngine::initialize(QAbstractSocket::SocketType socketType, QAb
         return false;
     }
 
-    // Make the socket nonblocking.
-    if (!setOption(NonBlockingSocketOption, 1)) {
-        d->setError(QAbstractSocket::UnsupportedSocketOperationError,
-                    QNativeSocketEnginePrivate::NonBlockingInitFailedErrorString);
-        close();
-        return false;
-    }
-
     // Set the broadcasting flag if it's a UDP socket.
     if (socketType == QAbstractSocket::UdpSocket
         && !setOption(BroadcastSocketOption, 1)) {

src/network/socket/qnativesocketengine_unix.cpp

@@ -138,10 +138,10 @@ bool QNativeSocketEnginePrivate::createNewSocket(QAbstractSocket::SocketType soc
     int protocol = (socketProtocol == QAbstractSocket::IPv6Protocol || socketProtocol == QAbstractSocket::AnyIPProtocol) ? AF_INET6 : AF_INET;
     int type = (socketType == QAbstractSocket::UdpSocket) ? SOCK_DGRAM : SOCK_STREAM;
 
-    int socket = qt_safe_socket(protocol, type, 0);
+    int socket = qt_safe_socket(protocol, type, 0, O_NONBLOCK);
     if (socket < 0 && socketProtocol == QAbstractSocket::AnyIPProtocol && errno == EAFNOSUPPORT) {
         protocol = AF_INET;
-        socket = qt_safe_socket(protocol, type, 0);
+        socket = qt_safe_socket(protocol, type, 0, O_NONBLOCK);
         socketProtocol = QAbstractSocket::IPv4Protocol;
     }
 

src/network/socket/qnativesocketengine_win.cpp

@@ -383,8 +383,15 @@ bool QNativeSocketEnginePrivate::createNewSocket(QAbstractSocket::SocketType soc
 #endif
 
     socketDescriptor = socket;
-    return true;
 
+    // Make the socket nonblocking.
+    if (!setOption(QAbstractSocketEngine::NonBlockingSocketOption, 1)) {
+        setError(QAbstractSocket::UnsupportedSocketOperationError, NonBlockingInitFailedErrorString);
+        q_func()->close();
+        return false;
+    }
+
+    return true;
 }
 
 /*! \internal

src/network/socket/qnativesocketengine_winrt.cpp

@@ -768,7 +768,7 @@ bool QNativeSocketEnginePrivate::createNewSocket(QAbstractSocket::SocketType soc
             return false;
         }
         socketDescriptor = qintptr(socket.Detach());
-        return true;
+        break;
     }
     case QAbstractSocket::UdpSocket: {
         ComPtr<IDatagramSocket> socket;
@@ -780,13 +780,21 @@ bool QNativeSocketEnginePrivate::createNewSocket(QAbstractSocket::SocketType soc
         EventRegistrationToken token;
         socketDescriptor = qintptr(socket.Detach());
         udpSocket()->add_MessageReceived(Callback<DatagramReceivedHandler>(this, &QNativeSocketEnginePrivate::handleNewDatagram).Get(), &token);
-        return true;
+        break;
     }
     default:
         qWarning("Invalid socket type");
         return false;
     }
-    return false;
+
+    // Make the socket nonblocking.
+    if (!setOption(QAbstractSocketEngine::NonBlockingSocketOption, 1)) {
+        setError(QAbstractSocket::UnsupportedSocketOperationError, NonBlockingInitFailedErrorString);
+        q_func()->close();
+        return false;
+    }
+
+    return true;
 }
 
 QNativeSocketEnginePrivate::QNativeSocketEnginePrivate()