public void RegisterAsPuppet()
{
Message m = new Message ();
m.SetMessageType ("puppet_register");
m.SetSourceUserName (m_client.UserName);
m.SetDestinationUsers (PUPPET_MASTER);
m_client.m_puppetSendReceiveMiddleLayer.Send (m);
}
public void RegisterAsPuppet()
{
Message m = new Message ();
m.SetMessageType ("puppet_register");
m.SetSourceUserName (m_server.UserName);
m.SetDestinationUsers (PUPPET_MASTER);
DebugInfo ("Registering server as puppet.... ");
m_server.m_puppetSendReceiveMiddleLayer.Send (m);
}
public void SendInfoMsgToPuppetMaster(string message, params object[] args)
{
Message m = new Message ();
m.SetMessageType ("puppet_info");
m.SetSourceUserName (m_server.UserName);
m.SetDestinationUsers (PUPPET_MASTER);
m.PushString (String.Format (message, args));
m_server.m_puppetSendReceiveMiddleLayer.Send (m);
}
public object Clone()
{
Message m = new Message ();
m.SetSourceUri (this.GetSourceUri ());
m.SetSourceUserName (this.GetSourceUserName ());
m.SetMessageType (this.GetMessageType ());
m.SetDestinationUsers (this.GetDestinationUsers ());
m.m_items = this.m_items;
return m;
}
public bool Disconnect()
{
// TODO: Don't forget to notify all peers about leave at this point
Message m = new Message ();
m.SetMessageType ("disconnect");
m.SetSourceUserName (m_master.UserName);
m.SetDestinationUsers ("SERVER");
DebugLogic ("Sending disconnection request");
m_master.m_sendReceiveMiddleLayer.Send (m);
return true;
// TODO: For now, no need to block on disconnect
}
public int RequestSequenceNumber()
{
lock (this){
Message m = new Message ();
m.SetSourceUserName (m_client.UserName);
m.SetDestinationUsers ("SERVER");
m.SetMessageType ("sequencenumber");
m_client.m_sendReceiveMiddleLayer.Send (m);
//This thread will block here until the reset event is sent.
oSignalEvent.WaitOne();
oSignalEvent.Reset ();
return m_sequenceNumberToReturn;
}
}
public bool Connect()
{
Message m = new Message ();
m.SetMessageType ("connect");
m.SetSourceUserName (m_master.UserName);
m.SetDestinationUsers ("SERVER");
DebugLogic ("Sending connection request");
m_master.m_sendReceiveMiddleLayer.Send (m);
//This thread will block here until the reset event is sent.
m_oSignalEvent.WaitOne();
m_oSignalEvent.Reset ();
return true;
}
public string Lookup(string user)
{
lock (this){
// TODO: This should later move into a lookup for
// a list of users.
// TODO: It should also implement a cache
// to avoid remote invocations all the time.
// TODO: Avoid restricted "SERVER" username
// registrations at server end.
// Lookup service knows the servers.
// It will also check the cache at a later stage of
// development.
if (user.Equals ("SERVER"))
{
// Return server 1. Will be changed later.
return m_client.CurrentMasterServer;
}
else if (user.Equals ("PUPPETMASTER"))
{
DebugUncond ("Returning address for puppet master {0}", m_client.PuppetMasterAddress);
return m_client.PuppetMasterAddress;
}
// If not SERVER or in cache, create a new
// lookup message destined to SERVER. Eventually,
// lower layer will query for SERVER, and this
// method will answer it.
Message m = new Message ();
m.SetSourceUserName (m_client.UserName);
m.SetDestinationUsers ("SERVER");
m.SetMessageType ("lookup");
m.PushString (user); // This should change to a list later
m_client.m_sendReceiveMiddleLayer.Send (m);
// This thread will block here until the reset event is sent.
// In this case, it happens when the Receive() method is invocated
// upon getting a response.
DebugInfo ("Sent Lookup request");
m_oSignalEvent.WaitOne();
DebugInfo ("Releasing block");
m_oSignalEvent.Reset ();
return m_lookupResponse;
}
}
public void Reserve(string description, List<string> userlist, List<int> slotlist)
{
// 1) Create reservation object
// TODO: Make sure m_client VALIDATES the inputs?
// TODO: At this point, we assume all requested slots are free.
Reservation reservation = new Reservation ();
reservation.m_description = description;
reservation.m_slotNumberList = slotlist;
reservation.m_userList = userlist;
reservation.m_reservationState = CalendarServiceClient.ReservationState.INITIATED;
reservation.m_acksForSlot = new Dictionary<int, int> ();
reservation.m_initiator = m_client.UserName;
// Update slot objects
foreach (int i in slotlist)
{
// If slot is being encountered for the
// first time...
if (!m_numberToSlotMap.ContainsKey (i))
{
DebugLogic ("Creating new slot instance for slot-number: {0}", i);
// Then create new slot.
// TODO: Probably need internal methods for this
Slot slot = new Slot ();
slot.m_calendarState = CalendarState.FREE;
slot.m_slotNumber = i;
slot.m_reservationsForThisSlot = new List<Reservation> ();
slot.m_preCommitList = new SortedList<int, Reservation> ();
slot.m_lockedReservation = -1;
// Add to int-to-slot-object map
m_numberToSlotMap.Add (i, slot);
}
// Update the slot's reservation list
m_numberToSlotMap[i].m_reservationsForThisSlot.Add (reservation);
}
//DebugUncond ("----->>>> {0} {1} <<---", userlist.Count, userlist[0]);
// Special case, book with yourself
if (userlist.Count == 1 && userlist[0] == m_client.UserName)
{
// TODO: Check if slot is in action perhaps.
foreach (int i in slotlist)
{
Slot s = m_numberToSlotMap[i];
if (s.m_calendarState != CalendarServiceClient.CalendarState.ASSIGNED
&& s.m_calendarState != CalendarServiceClient.CalendarState.BOOKED)
{
s.m_calendarState = CalendarServiceClient.CalendarState.ASSIGNED;
reservation.m_reservationState = CalendarServiceClient.ReservationState.COMMITTED;
s.m_lockedReservation = i;
return;
}
}
}
// 2) Obtain sequence number
reservation.m_sequenceNumber = m_client.GetSequenceNumber ();
// 2) Maintain reservation session as per sequence number
// Add reservation object to int-to-reservation-object map.
m_activeReservationSessions.Add (reservation.m_sequenceNumber, reservation);
DebugLogic ("Created reservation object for" +
"[Desc: {0}, Users: {1}, Slots: {2} Seq: {3}]",description, userlist, slotlist, reservation.m_sequenceNumber);
// Else, trim yourself out of the list (position 0).
// Surely it is yourself, but sanity checks are good.
if (m_client.UserName.Equals (userlist[0]))
{
userlist.RemoveAt(0);
}
// 3) Disseminate reservation request
DebugLogic ("Dissemination reservation request " +
"[Desc: {0}, Users: {1}, Slots: {2}]",description, userlist, slotlist);
Message reservationRequest = new Message ();
/* Message format for reservations (stack part) is as follows:
*
* - SubType TODO: Later register more types up there.
* - ReservationSequenceNumber
* - User NumberOfSlots
* - NumberOfSlots
* - Slot 1
* - Slot 2
* ...
* - Slot NumberOfUsers
* - Description
*/
reservationRequest.SetDestinationUsers (userlist);
reservationRequest.SetMessageType ("calendar");
reservationRequest.SetSourceUserName (m_client.UserName);
// Data part. Things will be pushed in the reverse order
// of the format
reservationRequest.PushString (description);
// Since we're pushing on to a stack and would like
// to retreive it in the same order at the other end.
slotlist.Reverse ();
foreach (int i in slotlist)
{
reservationRequest.PushString (i.ToString ());
}
reservationRequest.PushString (reservation.m_slotNumberList.Count.ToString ());
reservationRequest.PushString (reservation.m_sequenceNumber.ToString ());
reservationRequest.PushString ("reservationrequest");
SendMessage (reservationRequest);
}
public void Receive(ReceiveMessageEventArgs eventargs)
{
// parse message and call appropriate action
Message m = eventargs.m_message;
string message_source = m.GetSourceUserName ();
string request_type = m.GetMessageType ();
string message_source_uri = m.GetSourceUri ();
if (request_type.Equals ("lookup"))
{
// Client has requested a username lookup,
// respond with the URI string for the
// user
string user_request = m.PopString ();
string uri = GetUriForUser (user_request);
DebugInfo ("Answering lookup for {0} with {1}", user_request, uri);
Message response = new Message ();
response.SetMessageType ("lookup");
response.SetDestinationUsers (message_source);
response.SetSourceUserName (m_server.UserName);
response.PushString (uri);
SendReply(response);
}
else if (request_type.Equals ("connect"))
{
if (!m_server.m_replicationService.IsMaster)
{
// TODO: reply, in future: redirect question?
DebugInfo ("Got request intended for master.");
m_server.m_replicationService.SendImNotMasterMessage (m);
return;
}
// add user to DB
UserConnect (message_source, message_source_uri);
// Send an ACK or the client starves to death
Message ack_message = new Message ();
ack_message.SetMessageType ("connect");
ack_message.SetDestinationUsers (message_source);
ack_message.SetSourceUserName (m_server.UserName);
// replicate message (implicit block)
m_server.m_replicationService.ReplicateUserConnect (message_source, message_source_uri);
SendReply (ack_message);
}
else if (request_type.Equals ("disconnect"))
{
if (!m_server.m_replicationService.IsMaster)
{
// TODO: reply, in future: redirect question?
DebugInfo ("Got request intended for master.");
m_server.m_replicationService.SendImNotMasterMessage (m);
return;
}
// remove from replicas (implicit block until 1 ack is received)
m_server.m_replicationService.ReplicateUserDisconnect (message_source);
UserDisconnect (message_source);
// TODO: Find a way to get an ACK across
// for a disconnect message
}
return;
}
private void SynchronizeUserTable()
{
Message m = new Message ();
m.SetMessageType ("sync_usertable");
m.SetDestinationUsers (CurrentMaster);
m.SetSourceUserName (m_server.UserName);
m_server.m_sendReceiveMiddleLayer.Send (m);
Block ();
}
private void Ping()
{
foreach (string server in m_server.ServerList)
{
string serverName = m_serverUriToServerNameMap[server];
if (!serverName.Equals (m_server.UserName))
{
try
{
Message m = new Message ();
m.SetSourceUserName (m_server.UserName);
m.SetMessageType ("ping");
m.SetDestinationUsers (serverName);
m_server.m_sendReceiveMiddleLayer.UnreliableSend (m, server);
// if server was previously unavailable
// add to replication list
if (!m_serverStatus[serverName])
{
AddToReplicationList (serverName);
}
UpdateServerStatus (serverName, true);
}
catch (Exception)
{
DebugInfo ("Could not reach: {0}", server);
// update serverStatus list
UpdateServerStatus (serverName, false);
RemoveFromReplicationList (serverName);
// if server is master, update current master
if (serverName.Equals (CurrentMaster) && m_serverStatusFailCount[serverName] >= FAIL_TOLERANCE)
{
ChooseNewMaster (serverName);
// if I became master..?
if (IsMaster)
{
DebugInfo ("I am master");
RemoveFromReplicationList (m_server.UserName);
}
}
}
}
}
}
private void HandleUserDisconnectReplication(string username, string replyTo)
{
m_server.m_userTableService.UserDisconnect (username);
Message ack = new Message ();
ack.SetMessageType ("replicate");
ack.SetDestinationUsers (replyTo);
ack.SetSourceUserName (m_server.UserName);
ack.PushString (username);
ack.PushString ("user_disconnect_ack");
m_server.m_sendReceiveMiddleLayer.Send (ack);
}
private void ReceiveReservationYes(Message m,
string src,
List<string> userlist,
int reservationSequenceNumber,
string messageSubType)
{
int s = Int32.Parse (m.PopString ());
DebugLogic ("Received YES for slot {0}, reservation number {1}",s,reservationSequenceNumber);
Slot slot = m_numberToSlotMap[s];
Reservation res = m_activeReservationSessions[reservationSequenceNumber];
int ackcount;
if (res.m_acksForSlot.ContainsKey (s))
{
res.m_acksForSlot[s]++;
ackcount = res.m_acksForSlot[s];
}
else
{
ackcount = 1;
res.m_acksForSlot[s] = ackcount;
}
if (ackcount == res.m_userList.Count
// the below two conditions are sanity checks.
&& res.m_reservationState != CalendarServiceClient.ReservationState.COMMITTED
&& m_numberToSlotMap[s].m_calendarState != CalendarServiceClient.CalendarState.ASSIGNED)
{
DebugLogic ("Woopee! I can haz slot! {0}", s);
//send DoCommit
Message docommitMsg = new Message ();
docommitMsg.SetSourceUserName (m_client.UserName);
docommitMsg.SetDestinationUsers (res.m_userList);
docommitMsg.SetMessageType ("calendar");
docommitMsg.PushString (s.ToString ());
docommitMsg.PushString (reservationSequenceNumber.ToString ());
docommitMsg.PushString ("docommit");
SendMessage (docommitMsg);
// If you have to send this, then you can commit.
// TODO: Handle 2/1, 1/2 deadlock.
slot.m_calendarState = CalendarServiceClient.CalendarState.ASSIGNED;
res.m_reservationState = CalendarServiceClient.ReservationState.COMMITTED;
}
}
private string DetermineMaster()
{
foreach (string serverUri in m_server.ServerList)
{
string serverName = m_serverUriToServerNameMap[serverUri];
if (!serverName.Equals (m_server.UserName))
{
try {
Message m = new Message ();
m.SetMessageType ("whoismaster");
m.SetDestinationUsers (serverName);
m.SetSourceUserName (m_server.UserName);
m_server.m_sendReceiveMiddleLayer.UnreliableSend (m, serverUri);
Block ();
if (m_masterReplyBuffer.Equals ("empty"))
{
continue; // ask next server
}
return m_masterReplyBuffer;
}
catch (Exception) // UnreliableSend throws exception if dest is not reachable
{
continue;
}
}
}
DebugLogic ("I'm the only server alive. I am master.");
return m_server.UserName;
}
public void SendImNotMasterMessage(Message msg)
{
DebugInfo ("Asking {0} to resend to {1}", msg.GetSourceUserName (), CurrentMaster);
Message m = new Message ();
m.SetMessageType ("resend");
m.SetDestinationUsers (msg.GetSourceUserName ());
m.MessageForResending = msg;
m.SetSourceUserName (m_server.UserName);
m.PushString (m_server.m_userTableService.Lookup (CurrentMaster));
m_server.m_sendReceiveMiddleLayer.Send (m,msg.GetSourceUri (), msg.GetSourceUserName ());
}
private void ReceiveReservationDoCommit(Message m,
string src,
List<string> userlist,
int reservationSequenceNumber,
string messageSubType)
{
int s = Int32.Parse (m.PopString ());
DebugLogic ("Received docommit for slot {0}, reservation number {1}",s,reservationSequenceNumber);
Slot slot = m_numberToSlotMap[s];
Reservation res = m_activeReservationSessions[reservationSequenceNumber];
slot.m_calendarState = CalendarServiceClient.CalendarState.ASSIGNED;
res.m_reservationState = CalendarServiceClient.ReservationState.COMMITTED;
DebugLogic ("Reservation ID: {0}, Slot: {1} has COMMITTED", reservationSequenceNumber, s);
if (m_client.m_isPuppetControlled)
{
m_client.m_puppetService.SendInfoMsgToPuppetMaster ("Reservation ID: {0}, Slot: {1} has COMMITTED",
reservationSequenceNumber, s);
}
// Perform cleanup of all reservation objects
foreach (int i in res.m_slotNumberList)
{
if (i != s)
{
m_numberToSlotMap[i].m_reservationsForThisSlot.Remove (res);
}
}
foreach (int i in slot.m_preCommitList.Keys)
{
Message abortmsg = new Message ();
abortmsg.SetDestinationUsers (m_activeReservationSessions[reservationSequenceNumber].m_initiator);
abortmsg.SetMessageType ("calendar");
abortmsg.SetSourceUserName (m_client.UserName);
abortmsg.PushString (s.ToString ()); // we need to mention the slot that is being aborted
abortmsg.PushString (reservationSequenceNumber.ToString ());
abortmsg.PushString ("abort");
SendMessage (abortmsg);
ReservationAbortCohort (i, s);
}
}
private void ReceiveReservationPreCommit(Message m,
string src,
List<string> userlist,
int reservationSequenceNumber,
string messageSubType)
{
/* If I get a PRECOMMIT update for a slot,
* and it is still in ACKNOWLEDGED state, then
* respond with YES!. Else, respond with a NO!
*
* If I responded with a YES, then
* move into PRECOMMIT state and begin
* verification and commit timers.
*
* When verification timer fires, verify
* your neighbours. TODO: Might need ping
* utility
*
* If verification fails, ABORT, else do nothing.
*
* When commit timer fires, commit.
*
* If I responded with a NO, then move
* into ABORT.
*
* If between any of the above, the coordinator
* sends an ABORT message, then ABORT. DUH!
*/
int s = Int32.Parse (m.PopString ());
DebugLogic ("Received precommit for slot {0}, reservation number {1}",s,reservationSequenceNumber);
Slot slot = m_numberToSlotMap[s];
Reservation res = m_activeReservationSessions[reservationSequenceNumber];
if (slot.m_calendarState == CalendarServiceClient.CalendarState.ACKNOWLEDGED
|| slot.m_calendarState == CalendarServiceClient.CalendarState.BOOKED)
{
if (slot.m_preCommitList.Count == 0 && slot.m_lockedReservation == -1)
{
res.m_reservationState = CalendarServiceClient.ReservationState.TENTATIVELY_BOOKED;
slot.m_calendarState = CalendarServiceClient.CalendarState.BOOKED;
// No one has a lock, so this reservation gets it.
Message yes = new Message ();
yes.SetDestinationUsers (src);
yes.SetMessageType ("calendar");
yes.SetSourceUserName (m_client.UserName);
yes.PushString (s.ToString ());
yes.PushString (reservationSequenceNumber.ToString ());
yes.PushString ("yes");
slot.m_lockedReservation = reservationSequenceNumber;
SendMessage (yes);
}
else if (slot.m_lockedReservation != -1 && slot.m_lockedReservation < s)
{
// Some reservation older is already locked, so wait.
slot.m_preCommitList.Add (reservationSequenceNumber, res);
}
else
{
// Add older reservation to queue, we may upgrade or abort this
// depending on the result of the next step
slot.m_preCommitList.Add (reservationSequenceNumber, res);
// A newer reservation has been locked. For now,
// we try and ABORT the newer one in favour of the older one.
// But the optimisation here would be for coordinators to
// initiate an is-there-a-deadlock check, which the cohort
// would ask the coordinator to initiate.
Message abortmsg = new Message ();
abortmsg.SetDestinationUsers (m_activeReservationSessions[reservationSequenceNumber].m_initiator);
abortmsg.SetMessageType ("calendar");
abortmsg.SetSourceUserName (m_client.UserName);
abortmsg.PushString (s.ToString ()); // we need to mention the slot that is being aborted
abortmsg.PushString (slot.m_lockedReservation.ToString ());
abortmsg.PushString ("abort");
SendMessage (abortmsg);
ReservationAbortCohort (slot.m_lockedReservation, s);
}
}
}
private void SendPreCommitMessage(Reservation res, int s)
{
// Now send a precommit message to everyone involved.
// Party time!
Message precommitMsg = new Message ();
precommitMsg.SetSourceUserName (m_client.UserName);
precommitMsg.SetDestinationUsers (res.m_userList);
DebugLogic ("SENDING PRECOMMIT TO {0} many ppl for slot {1}", res.m_userList.Count, s);
precommitMsg.SetMessageType ("calendar");
precommitMsg.PushString (s.ToString ());
precommitMsg.PushString (res.m_sequenceNumber.ToString ());
precommitMsg.PushString ("precommit");
SendMessage (precommitMsg);
res.m_acksForSlot.Clear ();
}
private void ReservationAbortCohort(int reservationSequenceNumber, int s)
{
Slot slot = m_numberToSlotMap[s];
Reservation oldReservation = m_activeReservationSessions[reservationSequenceNumber];
oldReservation.m_slotNumberList.Remove (s);
// The earlier reservation is now removed from this slot
slot.m_reservationsForThisSlot.Remove (oldReservation);
// If this was the last slot in contention for
// the reservation...
if (oldReservation.m_slotNumberList.Count == 0)
{
// ... then the reservation should be in ABORTED state. Sigh.
oldReservation.m_reservationState = CalendarServiceClient.ReservationState.ABORTED;
}
// This slot is currently locked, only an abort can kill it.
if (slot.m_lockedReservation == reservationSequenceNumber)
{
// Promote next reservation in precommit queue
if (slot.m_preCommitList.Count > 0)
{
slot.m_lockedReservation = slot.m_preCommitList.Keys[0]; // Lock top queue elements
slot.m_preCommitList.RemoveAt (0); // remove top element from queue.
Reservation newres = m_activeReservationSessions[slot.m_lockedReservation];
// Send a yes message for the succeeding reservation
Message yes = new Message ();
yes.SetDestinationUsers (m_activeReservationSessions[slot.m_lockedReservation].m_initiator);
yes.SetMessageType ("calendar");
yes.SetSourceUserName (m_client.UserName);
yes.PushString (slot.m_slotNumber.ToString ());
yes.PushString (newres.m_sequenceNumber.ToString ());
yes.PushString ("yes");
SendMessage (yes);
}
else
{
// We don't have any more reservations for this slot, so
// let's keep it in the ACKNOWLEDGED state.
slot.m_calendarState = CalendarServiceClient.CalendarState.ACKNOWLEDGED;
// Release locks
slot.m_lockedReservation = -1;
}
}
else
{
// This slot is in the precommit list
slot.m_preCommitList.Remove (s);
}
}
private void HandleSequenceNumberReplication(string number, string replyTo)
{
m_server.m_sequenceNumberService.SetSequenceNumber (Int32.Parse (number));
Message ack = new Message ();
ack.SetMessageType ("replicate");
ack.SetDestinationUsers (replyTo);
ack.SetSourceUserName (m_server.UserName);
ack.PushString (number);
ack.PushString ("sequencenumber_ack");
m_server.m_sendReceiveMiddleLayer.Send (ack);
}
public bool CommandClient(PuppetInstruction instruction)
{
if (!Clients.ContainsKey(instruction.ApplyToUser))
{
if (instruction.Type == PuppetInstructionType.CONNECT)
{
if (instruction.ApplyToUser.Contains ("central"))
{
DebugLogic ("Starting new server: {0}", instruction.ApplyToUser);
SpawnServer(instruction.ApplyToUser);
// server will self-register, safe to return
return true;
}
else
{
DebugLogic ("Starting a new client: {0}", instruction.ApplyToUser);
SpawnClient (instruction.ApplyToUser);
// client will register with puppet master when initing, safe to return
return true;
}
}
DebugLogic ("No such user is connected: {0}", instruction.ApplyToUser);
return false;
}
else if (instruction.Type == PuppetInstructionType.DISCONNECT
&& instruction.ApplyToUser.Contains ("central"))
{
Clients.Remove (instruction.ApplyToUser);
try
{
SpawnedClients[instruction.ApplyToUser].Kill ();
SpawnedClients.Remove (instruction.ApplyToUser);
return true;
}
catch (InvalidOperationException)
{
DebugLogic ("Couldn't kill server: {0}", instruction.ApplyToUser);
}
}
Message m = new Message ();
m.SetSourceUserName ("puppetmaster");
m.SetDestinationUsers (instruction.ApplyToUser);
m.SetMessageType ("puppetmaster");
switch (instruction.Type)
{
case PuppetInstructionType.RESERVATION:
m.PushString (BuildStringList (instruction.Slots));
m.PushString (BuildStringList (instruction.Users));
m.PushString (instruction.Description);
m.PushString (instruction.Type.ToString ());
break;
default:
m.PushString (instruction.Type.ToString ());
break;
}
m_puppetMaster.m_sendReceiveMiddleLayer.Send (m);
return true;
}
private void ReceiveReservationRequest(Message m,
string src,
List<string> userlist,
int reservationSequenceNumber,
string messageSubType)
{
/* If I get a reservation request for a slot
* that is either FREE or ACKNOWLEDGED, then
* respond with an ACK, else if it is either
* BOOKED, or ASSIGNED, then respond with a NACK
*/
int numSlots = Int32.Parse (m.PopString ()); // number of slots
List<int> slotlist = new List<int> (); // unpack all the slots
for (int i = 0; i < numSlots; i++)
{
slotlist.Add (Int32.Parse (m.PopString ()));
}
string description = m.PopString (); // description
DebugLogic ("Received Message:" +
"[{0}, {1}, {2}, {3}, {4}, {5}, {6}]",
src, userlist.ToString (), messageSubType, reservationSequenceNumber, numSlots, slotlist.ToString (), description);
/* Message unpacked, now create a reservation object
*/
if (m_activeReservationSessions.ContainsKey (reservationSequenceNumber))
{
DebugFatal ("Duplicate reservation request received {0}", reservationSequenceNumber);
}
/* Create reservation object
*/
Reservation reservation = new Reservation ();
reservation.m_description = description;
reservation.m_sequenceNumber = reservationSequenceNumber;
reservation.m_userList = userlist;
reservation.m_slotNumberList = slotlist;
reservation.m_initiator = src;
/*
* check if slots are free
* and proceed to respond with an ACK or NACK.
*/
List<int> availableslots = new List<int> ();
foreach (int i in slotlist)
{
// If slot is being encountered for the
// first time...
if (!m_numberToSlotMap.ContainsKey (i))
{
DebugLogic ("Creating new slot instance for slot-number: {0}", i);
// Then create new slot.
// TODO: Probably need internal methods for this
Slot tempslot = new Slot ();
tempslot.m_calendarState = CalendarState.FREE;
tempslot.m_slotNumber = i;
tempslot.m_reservationsForThisSlot = new List<Reservation> ();
tempslot.m_preCommitList = new SortedList<int, Reservation> ();
tempslot.m_lockedReservation = -1;
// Add to int-to-slot-object map
m_numberToSlotMap.Add (i, tempslot);
}
// Get the concerned slot
Slot slot = m_numberToSlotMap[i];
if (slot.m_calendarState == CalendarServiceClient.CalendarState.FREE ||
slot.m_calendarState == CalendarServiceClient.CalendarState.ACKNOWLEDGED)
{
// Update the slot's reservation list
slot.m_reservationsForThisSlot.Add (reservation);
// Append to list of slots.
availableslots.Add (i);
// Update slot state
slot.m_calendarState = CalendarServiceClient.CalendarState.ACKNOWLEDGED;
DebugLogic ("Slot {0} is now in ACKNOWLEDGED state", i);
}
}
// Respond with ACK/NACK
if (availableslots.Count > 0)
{
// We do have at least one free slot, so respond with an ACK
Message ack = new Message ();
ack.SetSourceUserName (m_client.UserName);
ack.SetDestinationUsers (src);
ack.SetMessageType ("calendar");
/*
* ACK Message format, data part
*
* - Number of Slots
* - Slot 1
* - Slot 2
* ...
* - Slot N
*/
availableslots.Reverse ();
foreach (int i in availableslots)
{
ack.PushString (i.ToString ());
DebugInfo ("Slot {0} is available", i);
}
ack.PushString (availableslots.Count.ToString ());
ack.PushString (reservationSequenceNumber.ToString ());
ack.PushString ("reservationack");
DebugLogic ("Sending an ack to: {0}", src);
SendMessage (ack);
m_activeReservationSessions.Add (reservationSequenceNumber, reservation);
}
else
{
Message nack = new Message ();
// No free slots, so respond with a NACK
nack.SetSourceUserName (m_client.UserName);
nack.SetDestinationUsers (src);
nack.SetMessageType ("calendar");
nack.PushString ("reservationnack");
DebugLogic ("Sending a nack to: {0}", src);
SendMessage (nack);
}
}
