private void TryCommitView(List <AcceptViewProposal> underlingsList, AcceptViewProposal bestState)
{
if (IsSelfPromotionAllowed())
{
Utils.Print($" [o] Commiting View Change...");
Task <ReplyData>[] tasksArray = InitiateServerCalls(underlingsList);
// We don't care about those replicas after informing them they should commit. If they fail, someone will detect it sooner or later.
}
AllowSelfPromotion();
}
private AcceptViewProposal SelectBestInitialState(List <AcceptViewProposal> underlingsList)
{
AcceptViewProposal bestProposal = underlingsList[0];
foreach (AcceptViewProposal underlingProposal in underlingsList)
{
View currentUnderlingView = underlingProposal.ServerView;
if (Utils.IsOtherViewBetter(bestProposal.ServerView, currentUnderlingView))
{
bestProposal = underlingProposal;
}
}
return(bestProposal);
}
public View TryViewChange(List <ServerData> knownLivingServers)
{
// TODO >> When servers accept a commit message they should end all their requests, alt incomming requests and wait for a commit.
// TODO >> After commit is done they should resume the requests
int cancelled = 0;
AllowSelfPromotion();
Utils.Print(" [o] Proposing new View to known living servers...");
#region Initialization
CancellationTokenSource tokenSource = new CancellationTokenSource();
tokenSource.CancelAfter(timeout);
CancellationToken cancellationToken = tokenSource.Token;
// Generate the new View.
serverView.IncrementViewId();
serverView.PromoteViewManager(managerOwner.ServerData);
serverView.ReplicasList = knownLivingServers;
List <AcceptViewProposal> underlingsList = new List <AcceptViewProposal>();
Task <ReplyData>[] tasksArray = InitiateServerCalls(serverView, cancellationToken);
try
{
Task.WaitAll(tasksArray, cancellationToken);
}
catch (OperationCanceledException) { cancelled++; }
bool aServerExplicitlyRefused = false;
for (int tidx = 0; tidx < tasksArray.Length; tidx++)
{
Task <ReplyData> task = tasksArray[tidx];
if (Utils.IsValidRemoteReply(task, typeof(AcceptViewProposal)))
{
underlingsList.Add((AcceptViewProposal)task.Result);
}
else if (Utils.IsValidRemoteReply(task, typeof(RejectViewProposal)))
{
aServerExplicitlyRefused = true;
}
else
{
knownLivingServers.Remove(((NoReply)task.Result).ServerData);
}
}
#endregion
if (Utils.MajorityHasAccepted(underlingsList.Count, tasksArray.Length - cancelled))
{
AcceptViewProposal bestProposal = SelectBestInitialState(underlingsList);
TryCommitView(underlingsList, bestProposal);
}
else if (!Utils.MajorityHasAccepted(underlingsList.Count, tasksArray.Length) || aServerExplicitlyRefused)
{
return(TryViewChange(knownLivingServers));
}
return(this.serverView);
}
