different strategy for mutex in protocol class, fix for sending jitter buffer change message when no connection is established

src/channel.h

@@ -87,7 +87,14 @@ public:
 	int GetSockBufSize() { return SockBuf.GetSize(); }
 
 	// network protocol interface
-	void CreateJitBufMes ( const int iJitBufSize ) { Protocol.CreateJitBufMes ( iJitBufSize ); }
+	void CreateJitBufMes ( const int iJitBufSize )
+	{ 
+		if ( IsConnected() )
+		{
+			Protocol.CreateJitBufMes ( iJitBufSize );
+		}
+	}
+
 	void CreateReqJitBufMes() { Protocol.CreateReqJitBufMes(); }
 
 protected:

src/protocol.cpp

@@ -46,7 +46,8 @@ MESSAGES
 	+--------------------------+
 
 - Request jitter buffer size:          PROTMESSID_REQ_JITT_BUF_SIZE
-	no data
+
+	note: does not have any data -> n = 0
 
 
 
@@ -95,8 +96,12 @@ void CProtocol::EnqueueMessage ( CVector<uint8_t>& vecMessage,
 	// create send message object for the queue
 	CSendMessage SendMessageObj ( vecMessage, iCnt, iID );
 
+	Mutex.lock();
+	{
 		// we want to have a FIFO: we add at the end and take from the beginning
 		SendMessQueue.push_back ( SendMessageObj );
+	}
+	Mutex.unlock();
 
 	// if list was empty, initiate send process
 	if ( bListWasEmpty )
@@ -106,13 +111,28 @@ void CProtocol::EnqueueMessage ( CVector<uint8_t>& vecMessage,
 }
 
 void CProtocol::SendMessage()
+{
+	CVector<uint8_t>	vecMessage;
+	bool				bSendMess = false;
+
+	Mutex.lock();
 	{
 		// we have to check that list is not empty, since in another thread the
 		// last element of the list might have been erased
 		if ( !SendMessQueue.empty() )
+		{
+			vecMessage.Init ( SendMessQueue.front().vecMessage.Size() );
+			vecMessage = SendMessQueue.front().vecMessage;
+
+			bSendMess = true;
+		}
+	}
+	Mutex.unlock();
+
+	if ( bSendMess )
 	{
 		// send message
-		emit MessReadyForSending ( SendMessQueue.front().vecMessage );
+		emit MessReadyForSending ( vecMessage );
 
 		// start time-out timer if not active
 		if ( !TimerSendMess.isActive() )
@@ -144,27 +164,11 @@ void CProtocol::CreateAndSendAcknMess ( const int& iID, const int& iCnt )
 }
 
 void CProtocol::DeleteSendMessQueue()
-{
-/*
-	Actually, this function must be secured by a mutex, too. The problem is that
-	this function is called from OnSendProtMessage in client which is called
-	from a mutexed function of this object. In this case, we will get a dead
-	lock.
-*/
-	// delete complete "send message queue"
-	SendMessQueue.clear();
-}
-
-
-/*
-	The following functions are access functions from different threads. These
-	functions have to be secured by a mutex to avoid data corruption
-*/
-void CProtocol::OnTimerSendMess()
 {
 	Mutex.lock();
 	{
-		SendMessage();
+		// delete complete "send message queue"
+		SendMessQueue.clear();
 	}
 	Mutex.unlock();
 }
@@ -176,12 +180,10 @@ bool CProtocol::ParseMessage ( const CVector<unsigned char>& vecbyData,
 	return code: true -> ok; false -> error
 */
 	bool				bRet;
-
-	Mutex.lock();
-	{
 	int					iRecCounter, iRecID, iData;
 	unsigned int		iPos;
 	CVector<uint8_t>	vecData;
+	bool				bSendNextMess;
 
 
 // convert unsigned char in uint8_t, TODO convert all buffers in uint8_t
@@ -218,6 +220,8 @@ for ( int i = 0; i < iNumBytes; i++ ) {
 				iPos = 0;
 				iData = static_cast<int> ( GetValFromStream ( vecData, iPos, 2 ) );
 
+				Mutex.lock();
+				{
 					// check if this is the correct acknowledgment
 					if ( ( SendMessQueue.front().iCnt == iRecCounter ) &&
 						 ( SendMessQueue.front().iID == iData ) )
@@ -226,6 +230,17 @@ for ( int i = 0; i < iNumBytes; i++ ) {
 						SendMessQueue.pop_front();
 
 						// send next message in queue
+						bSendNextMess = true;
+					}
+					else
+					{
+						bSendNextMess = false;
+					}
+				}
+				Mutex.unlock();
+
+				if ( bSendNextMess )
+				{
 					SendMessage();
 				}
 
@@ -267,25 +282,26 @@ for ( int i = 0; i < iNumBytes; i++ ) {
 	{
 		bRet = false; // return error code
 	}
-	}
-	Mutex.unlock();
 
 	return bRet;
 }
 
 void CProtocol::CreateJitBufMes ( const int iJitBufSize )
-{
-	Mutex.lock();
 {
 	CVector<uint8_t>	vecNewMessage;
 	CVector<uint8_t>	vecData ( 2 ); // 2 bytes of data
+	int					iCurCounter;
 	unsigned int		iPos = 0; // init position pointer
 
+	Mutex.lock();
+	{
 		// store current counter value
-		const int iCurCounter = iCounter;
+		iCurCounter = iCounter;
 
 		// increase counter (wraps around automatically)
 		iCounter++;
+	}
+	Mutex.unlock();
 
 	// build data vector
 	PutValOnStream ( vecData, iPos, static_cast<uint32_t> ( iJitBufSize ), 2 );
@@ -296,20 +312,21 @@ void CProtocol::CreateJitBufMes ( const int iJitBufSize )
 	// enqueue message
 	EnqueueMessage ( vecNewMessage, iCurCounter, PROTMESSID_JITT_BUF_SIZE );
 }
-	Mutex.unlock();
-}
 
 void CProtocol::CreateReqJitBufMes()
 {
+	CVector<uint8_t>	vecNewMessage;
+	int					iCurCounter;
+
 	Mutex.lock();
 	{
-		CVector<uint8_t> vecNewMessage;
-
 		// store current counter value
-		const int iCurCounter = iCounter;
+		iCurCounter = iCounter;
 
 		// increase counter (wraps around automatically)
 		iCounter++;
+	}
+	Mutex.unlock();
 
 	// build complete message
 	GenMessageFrame ( vecNewMessage, iCurCounter, PROTMESSID_REQ_JITT_BUF_SIZE, CVector<uint8_t> ( 0 ) );
@@ -317,8 +334,6 @@ void CProtocol::CreateReqJitBufMes()
 	// enqueue message
 	EnqueueMessage ( vecNewMessage, iCurCounter, PROTMESSID_REQ_JITT_BUF_SIZE );
 }
-	Mutex.unlock();
-}
 
 
 /******************************************************************************\

src/protocol.h

@@ -117,15 +117,17 @@ protected:
 
 	void SendMessage();
 
-	uint8_t					iCounter;
 	int						iOldRecID, iOldRecCnt;
+
+	// these two objects must be sequred by a mutex
+	uint8_t					iCounter;
 	std::list<CSendMessage>	SendMessQueue;
 
 	QTimer					TimerSendMess;
 	QMutex					Mutex;
 
 public slots:
-	void OnTimerSendMess();
+	void OnTimerSendMess() { SendMessage(); }
 
 signals:
 	// transmitting