Minimize number of system calls at opening

Currently, the method QSP::open() several times calls the system
functions to get/set of DCB/termios structures for each parameter.
It is not rational and should be minimized as possible, in ideally
to once executed.

Change-Id: If1f308176a82f3c8896fc648bf656f089e099f3f
Reviewed-by: Sergey Belyashov <Sergey.Belyashov@gmail.com>
Reviewed-by: Denis Shienkov <denis.shienkov@gmail.com>

3 files changed, 233 insertions, 169 deletions

diff --git a/src/serialport/qserialport.cpp b/src/serialport/qserialport.cpp
index 45f56c8..d4e9a4f 100644
--- a/src/serialport/qserialport.cpp
+++ b/src/serialport/qserialport.cpp
@@ -568,15 +568,6 @@ bool QSerialPort::open(OpenMode mode)
     if (!d->open(mode))
         return false;
 
-    if (!d->setBaudRate()
-        || !d->setDataBits(d->dataBits)
-        || !d->setParity(d->parity)
-        || !d->setStopBits(d->stopBits)
-        || !d->setFlowControl(d->flowControl)) {
-        d->close();
-        return false;
-    }
-
     QIODevice::open(mode);
     return true;
 }
diff --git a/src/serialport/qserialport_unix.cpp b/src/serialport/qserialport_unix.cpp
index acc53c8..acd76b5 100644
--- a/src/serialport/qserialport_unix.cpp
+++ b/src/serialport/qserialport_unix.cpp
@@ -193,6 +193,120 @@ private:
     QSerialPortPrivate *dptr;
 };
 
+static inline void qt_set_common_props(termios *tio, QIODevice::OpenMode m)
+{
+#ifdef Q_OS_SOLARIS
+    tio->c_iflag &= ~(IMAXBEL|IGNBRK|BRKINT|PARMRK|ISTRIP|INLCR|IGNCR|ICRNL|IXON);
+    tio->c_oflag &= ~OPOST;
+    tio->c_lflag &= ~(ECHO|ECHONL|ICANON|ISIG|IEXTEN);
+    tio->c_cflag &= ~(CSIZE|PARENB);
+    tio->c_cflag |= CS8;
+#else
+    ::cfmakeraw(tio);
+#endif
+
+    tio->c_cflag |= CLOCAL;
+    tio->c_cc[VTIME] = 0;
+    tio->c_cc[VMIN] = 0;
+
+    if (m & QIODevice::ReadOnly)
+        tio->c_cflag |= CREAD;
+}
+
+static inline void qt_set_databits(termios *tio, QSerialPort::DataBits databits)
+{
+    tio->c_cflag &= ~CSIZE;
+    switch (databits) {
+    case QSerialPort::Data5:
+        tio->c_cflag |= CS5;
+        break;
+    case QSerialPort::Data6:
+        tio->c_cflag |= CS6;
+        break;
+    case QSerialPort::Data7:
+        tio->c_cflag |= CS7;
+        break;
+    case QSerialPort::Data8:
+        tio->c_cflag |= CS8;
+        break;
+    default:
+        tio->c_cflag |= CS8;
+        break;
+    }
+}
+
+static inline void qt_set_parity(termios *tio, QSerialPort::Parity parity)
+{
+    tio->c_iflag &= ~(PARMRK | INPCK);
+    tio->c_iflag |= IGNPAR;
+
+    switch (parity) {
+
+#ifdef CMSPAR
+    // Here Installation parity only for GNU/Linux where the macro CMSPAR.
+    case QSerialPort::SpaceParity:
+        tio->c_cflag &= ~PARODD;
+        tio->c_cflag |= PARENB | CMSPAR;
+        break;
+    case QSerialPort::MarkParity:
+        tio->c_cflag |= PARENB | CMSPAR | PARODD;
+        break;
+#endif
+    case QSerialPort::NoParity:
+        tio->c_cflag &= ~PARENB;
+        break;
+    case QSerialPort::EvenParity:
+        tio->c_cflag &= ~PARODD;
+        tio->c_cflag |= PARENB;
+        break;
+    case QSerialPort::OddParity:
+        tio->c_cflag |= PARENB | PARODD;
+        break;
+    default:
+        tio->c_cflag |= PARENB;
+        tio->c_iflag |= PARMRK | INPCK;
+        tio->c_iflag &= ~IGNPAR;
+        break;
+    }
+}
+
+static inline void qt_set_stopbits(termios *tio, QSerialPort::StopBits stopbits)
+{
+    switch (stopbits) {
+    case QSerialPort::OneStop:
+        tio->c_cflag &= ~CSTOPB;
+        break;
+    case QSerialPort::TwoStop:
+        tio->c_cflag |= CSTOPB;
+        break;
+    default:
+        tio->c_cflag &= ~CSTOPB;
+        break;
+    }
+}
+
+static inline void qt_set_flowcontrol(termios *tio, QSerialPort::FlowControl flowcontrol)
+{
+    switch (flowcontrol) {
+    case QSerialPort::NoFlowControl:
+        tio->c_cflag &= ~CRTSCTS;
+        tio->c_iflag &= ~(IXON | IXOFF | IXANY);
+        break;
+    case QSerialPort::HardwareControl:
+        tio->c_cflag |= CRTSCTS;
+        tio->c_iflag &= ~(IXON | IXOFF | IXANY);
+        break;
+    case QSerialPort::SoftwareControl:
+        tio->c_cflag &= ~CRTSCTS;
+        tio->c_iflag |= IXON | IXOFF | IXANY;
+        break;
+    default:
+        tio->c_cflag &= ~CRTSCTS;
+        tio->c_iflag &= ~(IXON | IXOFF | IXANY);
+        break;
+    }
+}
+
 bool QSerialPortPrivate::open(QIODevice::OpenMode mode)
 {
     QString lockFilePath = serialPortLockFilePath(QSerialPortInfoPrivate::portNameFromSystemLocation(systemLocation));
@@ -605,24 +719,8 @@ bool QSerialPortPrivate::setDataBits(QSerialPort::DataBits dataBits)
     if (!getTermios(&tio))
         return false;
 
-    tio.c_cflag &= ~CSIZE;
-    switch (dataBits) {
-    case QSerialPort::Data5:
-        tio.c_cflag |= CS5;
-        break;
-    case QSerialPort::Data6:
-        tio.c_cflag |= CS6;
-        break;
-    case QSerialPort::Data7:
-        tio.c_cflag |= CS7;
-        break;
-    case QSerialPort::Data8:
-        tio.c_cflag |= CS8;
-        break;
-    default:
-        tio.c_cflag |= CS8;
-        break;
-    }
+    qt_set_databits(&tio, dataBits);
+
     return setTermios(&tio);
 }
 
@@ -632,37 +730,7 @@ bool QSerialPortPrivate::setParity(QSerialPort::Parity parity)
     if (!getTermios(&tio))
         return false;
 
-    tio.c_iflag &= ~(PARMRK | INPCK);
-    tio.c_iflag |= IGNPAR;
-
-    switch (parity) {
-
-#ifdef CMSPAR
-    // Here Installation parity only for GNU/Linux where the macro CMSPAR.
-    case QSerialPort::SpaceParity:
-        tio.c_cflag &= ~PARODD;
-        tio.c_cflag |= PARENB | CMSPAR;
-        break;
-    case QSerialPort::MarkParity:
-        tio.c_cflag |= PARENB | CMSPAR | PARODD;
-        break;
-#endif
-    case QSerialPort::NoParity:
-        tio.c_cflag &= ~PARENB;
-        break;
-    case QSerialPort::EvenParity:
-        tio.c_cflag &= ~PARODD;
-        tio.c_cflag |= PARENB;
-        break;
-    case QSerialPort::OddParity:
-        tio.c_cflag |= PARENB | PARODD;
-        break;
-    default:
-        tio.c_cflag |= PARENB;
-        tio.c_iflag |= PARMRK | INPCK;
-        tio.c_iflag &= ~IGNPAR;
-        break;
-    }
+    qt_set_parity(&tio, parity);
 
     return setTermios(&tio);
 }
@@ -673,17 +741,8 @@ bool QSerialPortPrivate::setStopBits(QSerialPort::StopBits stopBits)
     if (!getTermios(&tio))
         return false;
 
-    switch (stopBits) {
-    case QSerialPort::OneStop:
-        tio.c_cflag &= ~CSTOPB;
-        break;
-    case QSerialPort::TwoStop:
-        tio.c_cflag |= CSTOPB;
-        break;
-    default:
-        tio.c_cflag &= ~CSTOPB;
-        break;
-    }
+    qt_set_stopbits(&tio, stopBits);
+
     return setTermios(&tio);
 }
 
@@ -693,24 +752,8 @@ bool QSerialPortPrivate::setFlowControl(QSerialPort::FlowControl flowControl)
     if (!getTermios(&tio))
         return false;
 
-    switch (flowControl) {
-    case QSerialPort::NoFlowControl:
-        tio.c_cflag &= ~CRTSCTS;
-        tio.c_iflag &= ~(IXON | IXOFF | IXANY);
-        break;
-    case QSerialPort::HardwareControl:
-        tio.c_cflag |= CRTSCTS;
-        tio.c_iflag &= ~(IXON | IXOFF | IXANY);
-        break;
-    case QSerialPort::SoftwareControl:
-        tio.c_cflag &= ~CRTSCTS;
-        tio.c_iflag |= IXON | IXOFF | IXANY;
-        break;
-    default:
-        tio.c_cflag &= ~CRTSCTS;
-        tio.c_iflag &= ~(IXON | IXOFF | IXANY);
-        break;
-    }
+    qt_set_flowcontrol(&tio, flowControl);
+
     return setTermios(&tio);
 }
 
@@ -825,25 +868,19 @@ inline bool QSerialPortPrivate::initialize(QIODevice::OpenMode mode)
         return false;
 
     restoredTermios = tio;
-#ifdef Q_OS_SOLARIS
-    tio.c_iflag &= ~(IMAXBEL|IGNBRK|BRKINT|PARMRK|ISTRIP|INLCR|IGNCR|ICRNL|IXON);
-    tio.c_oflag &= ~OPOST;
-    tio.c_lflag &= ~(ECHO|ECHONL|ICANON|ISIG|IEXTEN);
-    tio.c_cflag &= ~(CSIZE|PARENB);
-    tio.c_cflag |= CS8;
-#else
-    ::cfmakeraw(&tio);
-#endif
-    tio.c_cflag |= CLOCAL;
-    tio.c_cc[VTIME] = 0;
-    tio.c_cc[VMIN] = 0;
 
-    if (mode & QIODevice::ReadOnly)
-        tio.c_cflag |= CREAD;
+    qt_set_common_props(&tio, mode);
+    qt_set_databits(&tio, dataBits);
+    qt_set_parity(&tio, parity);
+    qt_set_stopbits(&tio, stopBits);
+    qt_set_flowcontrol(&tio, flowControl);
 
     if (!setTermios(&tio))
         return false;
 
+    if (!setBaudRate())
+        return false;
+
     if (mode & QIODevice::ReadOnly)
         setReadNotificationEnabled(true);
 
diff --git a/src/serialport/qserialport_win.cpp b/src/serialport/qserialport_win.cpp
index 7cbb81d..f4f8317 100644
--- a/src/serialport/qserialport_win.cpp
+++ b/src/serialport/qserialport_win.cpp
@@ -81,6 +81,94 @@
 
 QT_BEGIN_NAMESPACE
 
+static inline void qt_set_common_props(DCB *dcb)
+{
+    dcb->fBinary = TRUE;
+    dcb->fAbortOnError = FALSE;
+    dcb->fNull = FALSE;
+    dcb->fErrorChar = FALSE;
+
+    if (dcb->fDtrControl == DTR_CONTROL_HANDSHAKE)
+        dcb->fDtrControl = DTR_CONTROL_DISABLE;
+}
+
+static inline void qt_set_baudrate(DCB *dcb, qint32 baudrate)
+{
+    dcb->BaudRate = baudrate;
+}
+
+static inline void qt_set_databits(DCB *dcb, QSerialPort::DataBits databits)
+{
+    dcb->ByteSize = databits;
+}
+
+static inline void qt_set_parity(DCB *dcb, QSerialPort::Parity parity)
+{
+    dcb->fParity = TRUE;
+    switch (parity) {
+    case QSerialPort::NoParity:
+        dcb->Parity = NOPARITY;
+        dcb->fParity = FALSE;
+        break;
+    case QSerialPort::OddParity:
+        dcb->Parity = ODDPARITY;
+        break;
+    case QSerialPort::EvenParity:
+        dcb->Parity = EVENPARITY;
+        break;
+    case QSerialPort::MarkParity:
+        dcb->Parity = MARKPARITY;
+        break;
+    case QSerialPort::SpaceParity:
+        dcb->Parity = SPACEPARITY;
+        break;
+    default:
+        dcb->Parity = NOPARITY;
+        dcb->fParity = FALSE;
+        break;
+    }
+}
+
+static inline void qt_set_stopbits(DCB *dcb, QSerialPort::StopBits stopbits)
+{
+    switch (stopbits) {
+    case QSerialPort::OneStop:
+        dcb->StopBits = ONESTOPBIT;
+        break;
+    case QSerialPort::OneAndHalfStop:
+        dcb->StopBits = ONE5STOPBITS;
+        break;
+    case QSerialPort::TwoStop:
+        dcb->StopBits = TWOSTOPBITS;
+        break;
+    default:
+        dcb->StopBits = ONESTOPBIT;
+        break;
+    }
+}
+
+static inline void qt_set_flowcontrol(DCB *dcb, QSerialPort::FlowControl flowcontrol)
+{
+    dcb->fInX = FALSE;
+    dcb->fOutX = FALSE;
+    dcb->fOutxCtsFlow = FALSE;
+    dcb->fRtsControl = RTS_CONTROL_DISABLE;
+    switch (flowcontrol) {
+    case QSerialPort::NoFlowControl:
+        break;
+    case QSerialPort::SoftwareControl:
+        dcb->fInX = TRUE;
+        dcb->fOutX = TRUE;
+        break;
+    case QSerialPort::HardwareControl:
+        dcb->fOutxCtsFlow = TRUE;
+        dcb->fRtsControl = RTS_CONTROL_HANDSHAKE;
+        break;
+    default:
+        break;
+    }
+}
+
 bool QSerialPortPrivate::open(QIODevice::OpenMode mode)
 {
     DWORD desiredAccess = 0;
@@ -319,7 +407,8 @@ bool QSerialPortPrivate::setBaudRate(qint32 baudRate, QSerialPort::Directions di
     if (!getDcb(&dcb))
         return false;
 
-    dcb.BaudRate = baudRate;
+    qt_set_baudrate(&dcb, baudRate);
+
     return setDcb(&dcb);
 }
 
@@ -329,7 +418,8 @@ bool QSerialPortPrivate::setDataBits(QSerialPort::DataBits dataBits)
     if (!getDcb(&dcb))
         return false;
 
-    dcb.ByteSize = dataBits;
+    qt_set_databits(&dcb, dataBits);
+
     return setDcb(&dcb);
 }
 
@@ -339,29 +429,8 @@ bool QSerialPortPrivate::setParity(QSerialPort::Parity parity)
     if (!getDcb(&dcb))
         return false;
 
-    dcb.fParity = TRUE;
-    switch (parity) {
-    case QSerialPort::NoParity:
-        dcb.Parity = NOPARITY;
-        dcb.fParity = FALSE;
-        break;
-    case QSerialPort::OddParity:
-        dcb.Parity = ODDPARITY;
-        break;
-    case QSerialPort::EvenParity:
-        dcb.Parity = EVENPARITY;
-        break;
-    case QSerialPort::MarkParity:
-        dcb.Parity = MARKPARITY;
-        break;
-    case QSerialPort::SpaceParity:
-        dcb.Parity = SPACEPARITY;
-        break;
-    default:
-        dcb.Parity = NOPARITY;
-        dcb.fParity = FALSE;
-        break;
-    }
+    qt_set_parity(&dcb, parity);
+
     return setDcb(&dcb);
 }
 
@@ -371,20 +440,8 @@ bool QSerialPortPrivate::setStopBits(QSerialPort::StopBits stopBits)
     if (!getDcb(&dcb))
         return false;
 
-    switch (stopBits) {
-    case QSerialPort::OneStop:
-        dcb.StopBits = ONESTOPBIT;
-        break;
-    case QSerialPort::OneAndHalfStop:
-        dcb.StopBits = ONE5STOPBITS;
-        break;
-    case QSerialPort::TwoStop:
-        dcb.StopBits = TWOSTOPBITS;
-        break;
-    default:
-        dcb.StopBits = ONESTOPBIT;
-        break;
-    }
+    qt_set_stopbits(&dcb, stopBits);
+
     return setDcb(&dcb);
 }
 
@@ -394,24 +451,8 @@ bool QSerialPortPrivate::setFlowControl(QSerialPort::FlowControl flowControl)
     if (!getDcb(&dcb))
         return false;
 
-    dcb.fInX = FALSE;
-    dcb.fOutX = FALSE;
-    dcb.fOutxCtsFlow = FALSE;
-    dcb.fRtsControl = RTS_CONTROL_DISABLE;
-    switch (flowControl) {
-    case QSerialPort::NoFlowControl:
-        break;
-    case QSerialPort::SoftwareControl:
-        dcb.fInX = TRUE;
-        dcb.fOutX = TRUE;
-        break;
-    case QSerialPort::HardwareControl:
-        dcb.fOutxCtsFlow = TRUE;
-        dcb.fRtsControl = RTS_CONTROL_HANDSHAKE;
-        break;
-    default:
-        break;
-    }
+    qt_set_flowcontrol(&dcb, flowControl);
+
     return setDcb(&dcb);
 }
 
@@ -623,17 +664,12 @@ inline bool QSerialPortPrivate::initialize()
 
     restoredDcb = dcb;
 
-    dcb.fBinary = TRUE;
-    dcb.fInX = FALSE;
-    dcb.fOutX = FALSE;
-    dcb.fAbortOnError = FALSE;
-    dcb.fNull = FALSE;
-    dcb.fErrorChar = FALSE;
-
-    if (dcb.fDtrControl == DTR_CONTROL_HANDSHAKE)
-        dcb.fDtrControl = DTR_CONTROL_DISABLE;
-
-    dcb.BaudRate = inputBaudRate;
+    qt_set_common_props(&dcb);
+    qt_set_baudrate(&dcb, inputBaudRate);
+    qt_set_databits(&dcb, dataBits);
+    qt_set_parity(&dcb, parity);
+    qt_set_stopbits(&dcb, stopBits);
+    qt_set_flowcontrol(&dcb, flowControl);
 
     if (!setDcb(&dcb))
         return false;