Do not use internal pre-cached RTS and DTR variables

Some devices do not support these signals, and returns an errors when attempt
to query it. But the QSP::open() always requests a status of these lines.
In this case the QSP::open() will return true, but also will setup an error
code (for example, QSP::UnsupportedOperationError for socat's devices in
Linux). That is unexpected behavior for the user.

It is reasonable do not query a state of these signals when opening.
Also we do not need to use of appropriate internal variables, and we can
remove it.

Change-Id: I277110014c20c1f2c3fdaed20c4582d1356897b9
Reviewed-by: Sergey Belyashov <Sergey.Belyashov@gmail.com>

2 files changed, 4 insertions, 14 deletions

diff --git a/src/serialport/qserialport.cpp b/src/serialport/qserialport.cpp
index 5e838c0..0e60036 100644
--- a/src/serialport/qserialport.cpp
+++ b/src/serialport/qserialport.cpp
@@ -70,8 +70,6 @@ QSerialPortPrivateData::QSerialPortPrivateData(QSerialPort *q)
     , stopBits(QSerialPort::OneStop)
     , flowControl(QSerialPort::NoFlowControl)
     , policy(QSerialPort::IgnorePolicy)
-    , dataTerminalReady(false)
-    , requestToSend(false)
 #if QT_DEPRECATED_SINCE(5,3)
     , settingsRestoredOnClose(true)
 #endif
@@ -531,10 +529,6 @@ bool QSerialPort::open(OpenMode mode)
     }
 
     QIODevice::open(mode);
-
-    d->dataTerminalReady = isDataTerminalReady();
-    d->requestToSend = isRequestToSend();
-
     return true;
 }
 
@@ -865,11 +859,10 @@ bool QSerialPort::setDataTerminalReady(bool set)
         return false;
     }
 
+    const bool dataTerminalReady = isDataTerminalReady();
     const bool retval = d->setDataTerminalReady(set);
-    if (retval && (d->dataTerminalReady != set)) {
-        d->dataTerminalReady = set;
+    if (retval && (dataTerminalReady != set))
         emit dataTerminalReadyChanged(set);
-    }
 
     return retval;
 }
@@ -913,11 +906,10 @@ bool QSerialPort::setRequestToSend(bool set)
         return false;
     }
 
+    const bool requestToSend = isRequestToSend();
     const bool retval = d->setRequestToSend(set);
-    if (retval && (d->requestToSend != set)) {
-        d->requestToSend = set;
+    if (retval && (requestToSend != set))
         emit requestToSendChanged(set);
-    }
 
     return retval;
 }
diff --git a/src/serialport/qserialport_p.h b/src/serialport/qserialport_p.h
index 6f39260..578d8a9 100644
--- a/src/serialport/qserialport_p.h
+++ b/src/serialport/qserialport_p.h
@@ -75,8 +75,6 @@ public:
     QSerialPort::StopBits stopBits;
     QSerialPort::FlowControl flowControl;
     QSerialPort::DataErrorPolicy policy;
-    bool dataTerminalReady;
-    bool requestToSend;
     bool settingsRestoredOnClose;
     QSerialPort * const q_ptr;
 };