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36
37 #ifndef QMODBUSTCPCLIENT_P_H
38 #define QMODBUSTCPCLIENT_P_H
39
40 #include <QtCore/qloggingcategory.h>
41 #include <QtNetwork/qhostaddress.h>
42 #include <QtNetwork/qtcpsocket.h>
43 #include "QtSerialBus/qmodbustcpclient.h"
44
45 #include "private/qmodbusclient_p.h"
46
47 //
48 // W A R N I N G
49 // -------------
50 //
51 // This file is not part of the Qt API. It exists purely as an
52 // implementation detail. This header file may change from version to
53 // version without notice, or even be removed.
54 //
55 // We mean it.
56 //
57
58 QT_BEGIN_NAMESPACE
59
Q_DECLARE_LOGGING_CATEGORY(QT_MODBUS)60 Q_DECLARE_LOGGING_CATEGORY(QT_MODBUS)
61 Q_DECLARE_LOGGING_CATEGORY(QT_MODBUS_LOW)
62
63 class QModbusTcpClientPrivate : public QModbusClientPrivate
64 {
65 Q_DECLARE_PUBLIC(QModbusTcpClient)
66
67 public:
68 void setupTcpSocket()
69 {
70 Q_Q(QModbusTcpClient);
71
72 m_socket = new QTcpSocket(q);
73
74 QObject::connect(m_socket, &QAbstractSocket::connected, q, [this]() {
75 qCDebug(QT_MODBUS) << "(TCP client) Connected to" << m_socket->peerAddress()
76 << "on port" << m_socket->peerPort();
77 Q_Q(QModbusTcpClient);
78 responseBuffer.clear();
79 q->setState(QModbusDevice::ConnectedState);
80 });
81
82 QObject::connect(m_socket, &QAbstractSocket::disconnected, q, [this]() {
83 qCDebug(QT_MODBUS) << "(TCP client) Connection closed.";
84 Q_Q(QModbusTcpClient);
85 q->setState(QModbusDevice::UnconnectedState);
86 cleanupTransactionStore();
87 });
88
89 QObject::connect(m_socket,
90 &QAbstractSocket::errorOccurred, q,
91 [this](QAbstractSocket::SocketError /*error*/)
92 {
93 Q_Q(QModbusTcpClient);
94
95 if (m_socket->state() == QAbstractSocket::UnconnectedState) {
96 cleanupTransactionStore();
97 q->setState(QModbusDevice::UnconnectedState);
98 }
99 q->setError(QModbusClient::tr("TCP socket error (%1).").arg(m_socket->errorString()),
100 QModbusDevice::ConnectionError);
101 });
102
103 QObject::connect(m_socket, &QIODevice::readyRead, q, [this](){
104 responseBuffer += m_socket->read(m_socket->bytesAvailable());
105 qCDebug(QT_MODBUS_LOW) << "(TCP client) Response buffer:" << responseBuffer.toHex();
106
107 while (!responseBuffer.isEmpty()) {
108 // can we read enough for Modbus ADU header?
109 if (responseBuffer.size() < mbpaHeaderSize) {
110 qCDebug(QT_MODBUS_LOW) << "(TCP client) Modbus ADU not complete";
111 return;
112 }
113
114 quint8 serverAddress;
115 quint16 transactionId, bytesPdu, protocolId;
116 QDataStream input(responseBuffer);
117 input >> transactionId >> protocolId >> bytesPdu >> serverAddress;
118
119 // stop the timer as soon as we know enough about the transaction
120 const bool knownTransaction = m_transactionStore.contains(transactionId);
121 if (knownTransaction && m_transactionStore[transactionId].timer)
122 m_transactionStore[transactionId].timer->stop();
123
124 qCDebug(QT_MODBUS) << "(TCP client) tid:" << Qt::hex << transactionId << "size:"
125 << bytesPdu << "server address:" << serverAddress;
126
127 // The length field is the byte count of the following fields, including the Unit
128 // Identifier and the PDU, so we remove on byte.
129 bytesPdu--;
130
131 int tcpAduSize = mbpaHeaderSize + bytesPdu;
132 if (responseBuffer.size() < tcpAduSize) {
133 qCDebug(QT_MODBUS) << "(TCP client) PDU too short. Waiting for more data";
134 return;
135 }
136
137 QModbusResponse responsePdu;
138 input >> responsePdu;
139 qCDebug(QT_MODBUS) << "(TCP client) Received PDU:" << responsePdu.functionCode()
140 << responsePdu.data().toHex();
141
142 responseBuffer.remove(0, tcpAduSize);
143
144 if (!knownTransaction) {
145 qCDebug(QT_MODBUS) << "(TCP client) No pending request for response with "
146 "given transaction ID, ignoring response message.";
147 } else {
148 processQueueElement(responsePdu, m_transactionStore[transactionId]);
149 }
150 }
151 });
152 }
153
154 QModbusReply *enqueueRequest(const QModbusRequest &request, int serverAddress,
155 const QModbusDataUnit &unit,
156 QModbusReply::ReplyType type) override
157 {
158 auto writeToSocket = [this](quint16 tId, const QModbusRequest &request, int address) {
159 QByteArray buffer;
160 QDataStream output(&buffer, QIODevice::WriteOnly);
161 output << tId << quint16(0) << quint16(request.size() + 1) << quint8(address) << request;
162
163 int writtenBytes = m_socket->write(buffer);
164 if (writtenBytes == -1 || writtenBytes < buffer.size()) {
165 Q_Q(QModbusTcpClient);
166 qCDebug(QT_MODBUS) << "(TCP client) Cannot write request to socket.";
167 q->setError(QModbusTcpClient::tr("Could not write request to socket."),
168 QModbusDevice::WriteError);
169 return false;
170 }
171 qCDebug(QT_MODBUS_LOW) << "(TCP client) Sent TCP ADU:" << buffer.toHex();
172 qCDebug(QT_MODBUS) << "(TCP client) Sent TCP PDU:" << request << "with tId:" <<Qt:: hex
173 << tId;
174 return true;
175 };
176
177 const int tId = transactionId();
178 if (!writeToSocket(tId, request, serverAddress))
179 return nullptr;
180
181 Q_Q(QModbusTcpClient);
182 auto reply = new QModbusReply(type, serverAddress, q);
183 const auto element = QueueElement{ reply, request, unit, m_numberOfRetries,
184 m_responseTimeoutDuration };
185 m_transactionStore.insert(tId, element);
186
187 q->connect(reply, &QObject::destroyed, q, [this, tId](QObject *) {
188 if (!m_transactionStore.contains(tId))
189 return;
190 const QueueElement element = m_transactionStore.take(tId);
191 if (element.timer)
192 element.timer->stop();
193 });
194
195 if (element.timer) {
196 q->connect(q, &QModbusClient::timeoutChanged,
197 element.timer.data(), QOverload<int>::of(&QTimer::setInterval));
198 QObject::connect(element.timer.data(), &QTimer::timeout, q, [this, writeToSocket, tId]() {
199 if (!m_transactionStore.contains(tId))
200 return;
201
202 QueueElement elem = m_transactionStore.take(tId);
203 if (elem.reply.isNull())
204 return;
205
206 if (elem.numberOfRetries > 0) {
207 elem.numberOfRetries--;
208 if (!writeToSocket(tId, elem.requestPdu, elem.reply->serverAddress()))
209 return;
210 m_transactionStore.insert(tId, elem);
211 elem.timer->start();
212 qCDebug(QT_MODBUS) << "(TCP client) Resend request with tId:" << Qt::hex << tId;
213 } else {
214 qCDebug(QT_MODBUS) << "(TCP client) Timeout of request with tId:" <<Qt::hex << tId;
215 elem.reply->setError(QModbusDevice::TimeoutError,
216 QModbusClient::tr("Request timeout."));
217 }
218 });
219 element.timer->start();
220 } else {
221 qCWarning(QT_MODBUS) << "(TCP client) No response timeout timer for request with tId:"
222 << Qt::hex << tId << ". Expected timeout:" << m_responseTimeoutDuration;
223 }
224 incrementTransactionId();
225
226 return reply;
227 }
228
229 // TODO: Review once we have a transport layer in place.
230 bool isOpen() const override
231 {
232 if (m_socket)
233 return m_socket->isOpen();
234 return false;
235 }
236
237 void cleanupTransactionStore()
238 {
239 if (m_transactionStore.isEmpty())
240 return;
241
242 qCDebug(QT_MODBUS) << "(TCP client) Cleanup of pending requests";
243
244 for (const auto &elem : qAsConst(m_transactionStore)) {
245 if (elem.reply.isNull())
246 continue;
247 elem.reply->setError(QModbusDevice::ReplyAbortedError,
248 QModbusClient::tr("Reply aborted due to connection closure."));
249 }
250 m_transactionStore.clear();
251 }
252
253 // This doesn't overflow, it rather "wraps around". Expected.
254 inline void incrementTransactionId() { m_transactionId++; }
255 inline int transactionId() const { return m_transactionId; }
256
257 QIODevice *device() const override { return m_socket; }
258
259 QTcpSocket *m_socket = nullptr;
260 QByteArray responseBuffer;
261 QHash<quint16, QueueElement> m_transactionStore;
262 int mbpaHeaderSize = 7;
263
264 private: // Private to avoid using the wrong id inside the timer lambda,
265 quint16 m_transactionId = 0; // capturing 'this' will not copy the id.
266 };
267
268 QT_END_NAMESPACE
269
270 #endif // QMODBUSTCPCLIENT_P_H
271