Report intermediate errors while in a Modbus send/receive cycle

Task-number: QTBUG-79312
Change-Id: Iec1f9a0427bd04ebb8ceb4c66ece96e443092a6e
Reviewed-by: Alex Blasche <alexander.blasche@qt.io>

5 files changed, 73 insertions, 2 deletions

diff --git a/src/serialbus/qmodbusdevice.cpp b/src/serialbus/qmodbusdevice.cpp
index ab8e126..7c81ebf 100644
--- a/src/serialbus/qmodbusdevice.cpp
+++ b/src/serialbus/qmodbusdevice.cpp
@@ -217,6 +217,27 @@ void QModbusDevice::setConnectionParameter(int parameter, const QVariant &value)
 */
 
 /*!
+    \since 6.0
+    \enum QModbusDevice::IntermediateError
+
+    This enum describes possible errors that can happen during a full send and
+    receive cycle for a Modbus reply.
+
+    \value ResponseCrcError         A Modbus response with a wrong CRC was received.
+    \value ResponseRequestMismatch  A Modbus response was received but did not
+                                    match the open request, probably due to the
+                                    PDU's function code not matching.
+
+    If any of the above intermediate errors occurred, the frame is likely
+    resent until the maximum number of retries has been reached.
+
+    The list of intermediate errors can be inspected from the \l QModbusReply
+    intermediate errors function.
+
+    \sa QModbusClient::numberOfRetries(), QModbusReply::intermediateErrors()
+*/
+
+/*!
     \fn QModbusDevice::errorOccurred(QModbusDevice::Error error)
 
     This signal is emitted when an error of the type, \a error, occurs.
diff --git a/src/serialbus/qmodbusdevice.h b/src/serialbus/qmodbusdevice.h
index 0e6dad7..0a51a84 100644
--- a/src/serialbus/qmodbusdevice.h
+++ b/src/serialbus/qmodbusdevice.h
@@ -86,6 +86,13 @@ public:
     };
     Q_ENUM(ConnectionParameter)
 
+    enum IntermediateError
+    {
+        ResponseCrcError,
+        ResponseRequestMismatch
+    };
+    Q_ENUM(IntermediateError)
+
     explicit QModbusDevice(QObject *parent = nullptr);
     ~QModbusDevice();
 
@@ -118,6 +125,7 @@ protected:
 Q_DECLARE_TYPEINFO(QModbusDevice::Error, Q_PRIMITIVE_TYPE);
 Q_DECLARE_TYPEINFO(QModbusDevice::State, Q_PRIMITIVE_TYPE);
 Q_DECLARE_TYPEINFO(QModbusDevice::ConnectionParameter, Q_PRIMITIVE_TYPE);
+Q_DECLARE_TYPEINFO(QModbusDevice::IntermediateError, Q_PRIMITIVE_TYPE);
 
 QT_END_NAMESPACE
 
diff --git a/src/serialbus/qmodbusreply.cpp b/src/serialbus/qmodbusreply.cpp
index caa2dd9..e5561c2 100644
--- a/src/serialbus/qmodbusreply.cpp
+++ b/src/serialbus/qmodbusreply.cpp
@@ -53,6 +53,7 @@ public:
     QString m_errorText;
     QModbusResponse m_response;
     QModbusReply::ReplyType m_type;
+    QVector<QModbusDevice::IntermediateError> m_intermediateErrors;
 };
 
 /*!
@@ -239,7 +240,6 @@ QString QModbusReply::errorString() const
     return d->m_errorText;
 }
 
-
 /*!
     Returns the type of the reply.
 
@@ -278,6 +278,41 @@ void QModbusReply::setRawResult(const QModbusResponse &response)
     d->m_response = response;
 }
 
+/*!
+    \since 6.0
+    \fn void intermediateErrorOccurred(QModbusDevice::IntermediateError error)
+
+    This signal is emitted when an error has been detected in the processing of
+    this reply. The error will be described by the error code \a error.
+*/
+
+/*!
+    \since 6.0
+
+    Returns the list of intermediate errors that might have happened during
+    the send-receive cycle of a Modbus request until the QModbusReply reports
+    to be finished.
+*/
+QVector<QModbusDevice::IntermediateError> QModbusReply::intermediateErrors() const
+{
+    Q_D(const QModbusReply);
+    return d->m_intermediateErrors;
+}
+
+/*!
+   \internal
+   \since 6.0
+
+    Adds an intermediate error to the list of intermediate errors.
+    This will also cause the \l intermediateErrorOccurred() signal to be emitted.
+*/
+void QModbusReply::addIntermediateError(QModbusDevice::IntermediateError error)
+{
+    Q_D(QModbusReply);
+    d->m_intermediateErrors.append(error);
+    emit intermediateErrorOccurred(error);
+}
+
 QT_END_NAMESPACE
 
 #include "moc_qmodbusreply.cpp"
diff --git a/src/serialbus/qmodbusreply.h b/src/serialbus/qmodbusreply.h
index ffefc89..7381912 100644
--- a/src/serialbus/qmodbusreply.h
+++ b/src/serialbus/qmodbusreply.h
@@ -37,6 +37,7 @@
 #ifndef QMODBUSREPLY_H
 #define QMODBUSREPLY_H
 
+#include <QtCore/qvector.h>
 #include <QtSerialBus/qmodbusdataunit.h>
 #include <QtSerialBus/qmodbusdevice.h>
 #include <QtSerialBus/qmodbuspdu.h>
@@ -77,9 +78,13 @@ public:
     void setFinished(bool isFinished);
     void setError(QModbusDevice::Error error, const QString &errorText);
 
+    QVector<QModbusDevice::IntermediateError> intermediateErrors() const;
+    void addIntermediateError(QModbusDevice::IntermediateError error);
+
 Q_SIGNALS:
     void finished();
     void errorOccurred(QModbusDevice::Error error);
+    void intermediateErrorOccurred(QModbusDevice::IntermediateError error);
 };
 Q_DECLARE_TYPEINFO(QModbusReply::ReplyType, Q_PRIMITIVE_TYPE);
 
diff --git a/src/serialbus/qmodbusrtuserialmaster_p.h b/src/serialbus/qmodbusrtuserialmaster_p.h
index d206eec..4c75951 100644
--- a/src/serialbus/qmodbusrtuserialmaster_p.h
+++ b/src/serialbus/qmodbusrtuserialmaster_p.h
@@ -98,7 +98,7 @@ private:
 class QModbusRtuSerialMasterPrivate : public QModbusClientPrivate
 {
     Q_DECLARE_PUBLIC(QModbusRtuSerialMaster)
-        enum State
+    enum State
     {
         Idle,
         WaitingForReplay,
@@ -165,6 +165,7 @@ public:
             qCWarning(QT_MODBUS) << "(RTU client) Discarding response with wrong CRC, received:"
                 << adu.checksum<quint16>() << ", calculated CRC:"
                 << QModbusSerialAdu::calculateCRC(adu.data(), adu.size());
+            m_queue.first().reply->addIntermediateError(QModbusClient::ResponseCrcError);
             return;
         }
 
@@ -172,6 +173,7 @@ public:
         if (!canMatchRequestAndResponse(response, adu.serverAddress())) {
             qCWarning(QT_MODBUS) << "(RTU client) Cannot match response with open request, "
                 "ignoring";
+            m_queue.first().reply->addIntermediateError(QModbusClient::ResponseRequestMismatch);
             return;
         }