Bugfix: One click source change now fully supported

Since the async nature of this protocol introduces race conditions when changing
the source of the projection, the possiblity that two servers exist at a moment
is still there. Even though we thought we do not support multiple sources. This
is the reason why _desiredProjectionSource is needed after all.

2 files changed, 67 insertions, 77 deletions

diff --git a/src/server/mainwindow/mainwindow.cpp b/src/server/mainwindow/mainwindow.cpp
index d7cab75..ab94535 100644
--- a/src/server/mainwindow/mainwindow.cpp
+++ b/src/server/mainwindow/mainwindow.cpp
@@ -316,8 +316,7 @@ void MainWindow::tellClientCurrentSituation(Client* client)
 		client->lockScreen(true);
 
 	if (_mode == Mode::Broadcast){
-		// _watchers.insert(client->id(), client);
-		client->setWatcher(true);
+		client->setDesiredProjectionSource(_streamingSource);
 		Client* c = getClientFromId(_streamingSource);
 		if (c != NULL) {
 			client->startVncClient(c);
@@ -660,8 +659,10 @@ void MainWindow::onButtonTutorToAll()
 			// Set all clients as watchers
 			for (QList<ConnectionFrame*>::iterator it(_clientFrames.begin()); it != _clientFrames.end(); ++it)
 			{
-				if ((*it)->client() != NULL && (*it)->client() != getClientFromId(_streamingSource))
-					(*it)->client()->setWatcher(true);
+				if ((*it)->client() != NULL && (*it)->client() != getClientFromId(_streamingSource)){
+					(*it)->client()->setDesiredProjectionSource(getTutorFrame()->client()->id());
+				}
+
 			}
 		}
 		else // If this mode is already active
@@ -702,25 +703,21 @@ void MainWindow::onButtonTutorToStudent()
 		// If this is the first call in this mode clear the watchers
 		if (_mode != Mode::Multicast)
 		{
-			// _watchers.clear();
 			for (QList<ConnectionFrame*>::iterator it(_clientFrames.begin()); it != _clientFrames.end(); ++it)
 			{
 				if ((*it)->client() != NULL)
-					(*it)->client()->setWatcher(false);
+					(*it)->client()->setDesiredProjectionSource(NO_SOURCE);
 			}
 		}
 
 		// If "to" already watches "from" stop it
-		// if (_watchers.contains(to->id()))
-		if (getClientFromId(getSelectedFrame()->client()->id())->isWatcher())
+		if (getSelectedFrame()->client()->isWatcher())
 		{
-			// _watchers.remove(to->id());
-			getClientFromId(getSelectedFrame()->client()->id())->setWatcher(false);
+			getSelectedFrame()->client()->setDesiredProjectionSource(NO_SOURCE);
 		}
 		else // list "to" as watcher
 		{
-			// _watchers.insert(to->id(), to);
-			getClientFromId(getSelectedFrame()->client()->id())->setWatcher(true);
+			getSelectedFrame()->client()->setDesiredProjectionSource(getTutorFrame()->client()->id());
 		}
 
 		_mode = Mode::Multicast;
@@ -746,31 +743,25 @@ void MainWindow::onButtonStudentToTutor()
 		QMessageBox::critical(this, tr("Projection"), sStrSourceOffline);
 	else if (getTutorFrame()->client() == NULL)
 		QMessageBox::critical(this, tr("Projection"), sStrTutorOffline);
-	else{
-		DisableButtons();
-
-		if (_mode != Mode::Unicast)
-		{
-			// If this is the first run in this mode set the tutor as watcher
-			for (QList<ConnectionFrame*>::iterator it(_clientFrames.begin()); it != _clientFrames.end(); ++it)
-				if ((*it)->client() != NULL)
-					(*it)->client()->setWatcher(getTutorFrame()->client()->id() == (*it)->client()->id());
-			_mode = Mode::Unicast;
-		}
-		else
+	else
+	{
+		// If this is not the first run in this mode and the current source is selected, stop the streaming.
+		if (_mode == Mode::Unicast && getSelectedFrame()->client()->id() == _streamingSource)
 		{
-			// If this mode is already active and the current source is selected, stop the streaming.
-			if (getSelectedFrame()->client()->id() == _streamingSource )
-			{
-				// Stop reset everything
-				_mode = Mode::None;
-				reset();
-				return;
-			}
-			// If another client is selected solely the current streaming source shall be changed.
-			// This should be handled by startVncServerIfNecessary(...).
+			// Stop reset everything
+			_mode = Mode::None;
+			reset();
+			return;
 		}
 
+		// Unset all clients desired sources. Except the tutors desired source, this has to be the selecteds frame
+		for (QList<ConnectionFrame*>::iterator it(_clientFrames.begin()); it != _clientFrames.end(); ++it)
+			if ((*it)->client() != NULL){
+				(*it)->client()->setDesiredProjectionSource(getTutorFrame()->client()->id() == (*it)->client()->id() ? getSelectedFrame()->client()->id():NO_SOURCE);
+				qDebug() << "ID" <<(*it)->client()->id() << "ds" << (*it)->client()->desiredProjectionSource() <<"ps"<<  (*it)->client()->projectionSource();
+}
+		DisableButtons();
+		_mode = Mode::Unicast;
 		startVncServerIfNecessary(getSelectedFrame()->client()->id());
 	}
 }
@@ -802,7 +793,8 @@ void MainWindow::onButtonStudentToTutorExclusive()
 			// If this is the first run in this mode set the tutor as watcher
 			for (QList<ConnectionFrame*>::iterator it(_clientFrames.begin()); it != _clientFrames.end(); ++it)
 				if ((*it)->client() != NULL)
-					(*it)->client()->setWatcher(getTutorFrame()->client()->id() == (*it)->client()->id());
+					// Unset all but tutors desired projection, which is student
+					(*it)->client()->setDesiredProjectionSource(getTutorFrame()->client()->id() == (*it)->client()->id() ? getSelectedFrame()->client()->id():NO_SOURCE);
 			_mode = Mode::LockedUnicast;
 		}
 		else
@@ -1062,46 +1054,34 @@ void MainWindow::onVncServerStateChange(Client* client)
 
 	if (client->isActiveVncServer())
 	{
-		if (_mode == Mode::Broadcast)
-		{
-			for (QList<ConnectionFrame*>::iterator it(_clientFrames.begin()); it != _clientFrames.end(); ++it)
-			{
-				if ((*it)->client() != NULL)
-				{
-					// Unlock all online clients
-					(*it)->client()->lockScreen(false);
-
-					// Start VNCclients on all online clients but source
-					if ((*it)->client() != client)
-						(*it)->client()->startVncClient(client);
-				}
-			}
-		}
-		else  // !Mode::Broadcast  --> Mode::LockedMC || Mode::MC
+//		if (_mode == Mode::Broadcast)
+//		{
+//			for (QList<ConnectionFrame*>::iterator it(_clientFrames.begin()); it != _clientFrames.end(); ++it)
+//			{
+//				if ((*it)->client() != NULL)
+//				{
+//					// Unlock all online clients
+//					(*it)->client()->lockScreen(false);
+
+//					// Start VNCclients on all online clients but source
+//					if ((*it)->client() != client)
+//						(*it)->client()->startVncClient(client);
+//				}
+//			}
+//		}
+//		else
 		{
+			// apply the desired projection sources
 			for (QList<ConnectionFrame*>::iterator it(_clientFrames.begin()); it != _clientFrames.end(); ++it)
 			{
 				// Ignore offline clients
 				if ( (*it)->client() != NULL)
 				{
-					// if (_watchers.contains((*it)->client()->id()))
-					if ((*it)->client()->isWatcher())
-					{
-						// Unlock destination and connect VNCclient
-						(*it)->client()->lockScreen(false);
+					qDebug() << "ID" <<(*it)->client()->id() << "ds" << (*it)->client()->desiredProjectionSource() <<"ps"<<  (*it)->client()->projectionSource();
+					if ( (*it)->client()->desiredProjectionSource() == client->id() )
 						(*it)->client()->startVncClient(client);
-					}
-					else if ((*it)->client()->id() == client->id() )
-					{
-						// Unlock source
-						(*it)->client()->lockScreen(false);
-					}
-					else
-					{
-						// Lock others and stop their clients
-						(*it)->client()->lockScreen(_mode == Mode::LockedUnicast);
-						(*it)->client()->stopVncClient();
-					}
+
+					(*it)->client()->lockScreen((*it)->client()->desiredProjectionSource() == NO_SOURCE &&  _mode == Mode::LockedUnicast);
 				}
 			}
 		}
@@ -1109,15 +1089,16 @@ void MainWindow::onVncServerStateChange(Client* client)
 	else
 	{
 		// VNC server stopped on some client or failed to start - reset local pending projection information
-		// foreach (Client *c, _watchers) {
-		//   c->stopVncClient();
-		// }
 		for (QList<ConnectionFrame*>::iterator it(_clientFrames.begin()); it != _clientFrames.end(); ++it)
 		{
 			if ((*it)->client() != NULL)
 			{
-				if ((*it)->client()->isWatcher())
+				if ((*it)->client()->desiredProjectionSource() == client->id()) {
+					(*it)->client()->setDesiredProjectionSource(NO_SOURCE);
 					(*it)->client()->stopVncClient();
+					if (_mode == Mode::LockedUnicast)
+						(*it)->client()->lockScreen(true);
+				}
 			}
 		}
 	}
@@ -1135,11 +1116,10 @@ void MainWindow::onVncClientStateChange(Client* client)
 	{
 		// VNC Client stopped -> remove from watchers
 		if (!client->isActiveVncClient()){
-			if (getClientFromId(client->id()) != NULL)
-				getClientFromId(client->id())->setWatcher(false);
+	//		client->setDesiredProjectionSource(NO_SOURCE);
 
 			/*
-			 * If noboody is watching the multicast stop VNC server
+			 * If nobody is watching the multicast stop VNC server
 			 * If the past connection of this client is not the current
 			 * _streamingSource then the manager has to have stopped it
 			 * already. This is necessary for the race condition when a server
diff --git a/src/server/net/client.h b/src/server/net/client.h
index 61b6a5b..6dbb5bd 100644
--- a/src/server/net/client.h
+++ b/src/server/net/client.h
@@ -10,6 +10,8 @@
 
 //class QSslSocket;
 
+#define NO_SOURCE 0
+
 struct ClientLogin
 {
 	bool accept;
@@ -33,15 +35,22 @@ public:
 	inline const QString& host() const { return _host; }
 	inline const QString  ip() const { return _socket->peerAddress().toString(); }
 	inline const int      id() const { return _id; }
+	inline const int      desiredProjectionSource(){ return _desiredSource; }
 	inline const int      projectionSource() const { return _projectionSource; }
 	inline const bool     isActiveVncClient() const { return _isActiveVncClient; }
 	inline const bool     isActiveVncServer() const { return _vncPort > 0; }
 	inline const bool     isLocked() const { return _locked; }
-	inline const bool     isWatcher() const { return _isWatcher; }
+	inline const bool     isWatcher() const { return _desiredSource != 0; }
+
+
 
 	// Setters
 	inline void setTutor(bool enable){ _isTutor = enable; }
 	inline void setWatcher(bool enable){ _isWatcher = enable; }
+	inline void setDesiredProjectionSource(int id){
+		qDebug() << "ID" <<_id  << " new source " << _desiredSource;
+		_desiredSource = id;
+	}
 
 	//Send message stuff
 	void startVncServer();
@@ -65,7 +74,8 @@ private:
 	int            _id; // this client's unique id
 	QString        _vncRwPass, _vncRoPass;
 	int            _vncPort; // VNCserver state. Greater 0 -> active on this port. Equals 0 -> no server.
-	int            _projectionSource; // VNCclient state. The source the client was or is connected to (depends on _isActiveVncClient)
+	int            _desiredSource; // The source the client shall be connected to
+	int            _projectionSource; // The source the client was or is connected to (depends on _isActiveVncClient)
 	bool           _isActiveVncClient; // VNCclient state. indicating that the client is displaying a remote screen via VNC
 	bool           _isTutor; // Flag indicating that the client has been set as a tutor
 	bool           _isWatcher; // Flag indicates that the client should watch to VNC Server.