public static void BlockTransaction(Transaction transaction, BaseAction blockedAction)
{
transaction.Status = TransactionStatus.Blocked;
transaction.QueuedCommands.Enqueue(blockedAction);
}
private static void WriteValue(BaseAction tempAction)
{
var action = (Write)tempAction;
List<Site> availableLocations = _siteList.GetRunningSitesWithVariable(action.VariableId);
string output = action.ActionName + " ";
//if there are no sites to read from
if (availableLocations.Count() == 0)
{
TransactionUtilities.BlockTransaction(action.Transaction, action);
output = output + "\n\tTransaction " + action.Transaction.Id +
" blocked due to unavailable sites to write to.";
}
else
{
//we need to get locks
List<Site> locks = LockAquirer.AquireWriteLocks(action, availableLocations);
if (locks.Count != 0)
{
foreach (Site temp in locks)
{
Variable variable = temp.GetVariable(action.VariableId);
variable.Set(action.Value);
//add a record saying we used the transaction
action.Transaction.SiteUsedList.Add(new SiteAccessRecord { Site = temp, TimeStamp = _systemClock.CurrentTick });
}
output = output + "Value Written:" +
locks.First().GetVariable(action.VariableId).GetValue(action.Transaction);
}
else
{
//wait die
var shouldAbort =
WaitDie.ShouldAbort(availableLocations.First().GetVariable(action.VariableId),
action.Transaction);
if (shouldAbort)
{
TransactionUtilities.AbortTransaction(action.Transaction);
output = output + "\n\tAborted Transaction " + action.Transaction.Id + " due to wait-die.";
}
else
{
TransactionUtilities.BlockTransaction(action.Transaction, action);
output = output + "\n\tTransaction " + action.Transaction.Id +
" blocked due to unavailable sites to write to.";
}
}
}
State.Add(output);
}
private static void ReadValue(BaseAction tempAction)
{
var action = (Read)tempAction;
List<Site> availableLocations = _siteList.GetRunningSitesWithVariable(action.VariableId);
string output = action.ActionName + " ";
//if there are no sites to read from
if (availableLocations.Count() == 0)
{
TransactionUtilities.BlockTransaction(action.Transaction, action);
output = output + "\nTransaction " + action.Transaction.Id +
" blocked due to unavailable sites to read from.";
return;
}
if (action.Transaction.IsReadOnly)
{
//read only, no locks needed
Site siteToReadFrom = availableLocations.First();
//add a record saying we used the transaction
action.Transaction.SiteUsedList.Add(new SiteAccessRecord { Site = siteToReadFrom, TimeStamp = _systemClock.CurrentTick });
output = output + "Value Read:" +
siteToReadFrom.GetVariable(action.VariableId).GetValue(action.Transaction);
}
else
{
//we need to get locks
List<Site> locks = LockAquirer.AquireReadLock(action, availableLocations);
if (locks.Count != 0)
{
output = output + "Value Read:" +
locks.First().GetVariable(action.VariableId).GetValue(action.Transaction);
action.Transaction.SiteUsedList.Add(new SiteAccessRecord { Site = locks.First(), TimeStamp = _systemClock.CurrentTick });
}
else
{
//wait die
var shouldAbort =
WaitDie.ShouldAbort(availableLocations.First().GetVariable(action.VariableId),
action.Transaction);
if (shouldAbort)
{
TransactionUtilities.AbortTransaction(action.Transaction);
output = output + "\nAborted Transaction " + action.Transaction.Id + " due to wait-die.";
}
else
{
TransactionUtilities.BlockTransaction(action.Transaction, action);
output = output + "\nTransaction " + action.Transaction.Id +
" blocked due to unavailable sites to read from.";
}
}
}
State.Add(output);
}
private static void ProcessEntity(BaseAction tempAction)
{
//begin a transaction of any type
if (tempAction is BeginTransaction)
{
((BeginTransaction)tempAction).Transaction.Status = TransactionStatus.Running;
((BeginTransaction)tempAction).Transaction.StartTime = _systemClock.CurrentTick;
State.Add(tempAction.ActionName);
}
if (tempAction is Read)
{
ReadValue(tempAction);
}
if (tempAction is Write)
{
WriteValue(tempAction);
}
if (tempAction is Dump)
{
var action = (Dump)tempAction;
if (action.DumpFull)
{
foreach (Site tempSite in _siteList.Sites)
{
string outputString = "Site: " + tempSite.Id + " - ";
var variables = tempSite.VariableList.OrderBy(x => x.Id);
foreach (Variable tempvar in variables)
{
outputString = outputString + tempvar.Id + ":" + tempvar.GetValue() + " ";
}
State.Add("Dump - " + outputString + " - " + (tempSite.IsFailed ? "(Down)" : "Up"));
}
}
else if (action.DumpObject.Substring(0, 1).ToLower().Equals("x"))
{
//print out variable at each site
List<Site> locations =
_siteList.FindVariable(VariableUtilities.VariableIdToInt(action.DumpObject).ToString());
string outputString = "Variable " + VariableUtilities.VariableIdToInt(action.DumpObject).ToString() +
" - ";
foreach (Site tempsite in locations)
{
Variable variable = tempsite.GetVariable(VariableUtilities.VariableIdToInt(action.DumpObject));
outputString = outputString + " " + tempsite.Id + ":" + variable.GetValue();
}
State.Add("Dump - " + outputString);
}
else
{
//print out all values at a given site
Site site = _siteList.GetSite(int.Parse(action.DumpObject));
string outputString = "Site - ";
foreach (Variable currentVar in site.VariableList)
{
outputString = outputString + " " + currentVar.Id + ":" + currentVar.GetValue();
}
State.Add("Dump - " + outputString);
}
}
if (tempAction is Fail)
{
var action = (Fail)tempAction;
State.Add(tempAction.ActionName);
action.Site.Fail();
}
if (tempAction is Recover)
{
var action = (Recover)tempAction;
State.Add(tempAction.ActionName);
action.Site.Recover();
}
if (tempAction is EndTransaction)
{
var action = (EndTransaction)tempAction;
bool wentDown = false;
//check if the site went down after we accessed it
foreach (SiteAccessRecord record in action.Transaction.SiteUsedList)
{
if (record.Site.DidGoDown(record))
wentDown = true;
}
if (wentDown) //it did, abort the transaction
{
TransactionUtilities.AbortTransaction(action.Transaction);
State.Add(action.Transaction.Id + " aborted due to site failure: " + action.Transaction.Id);
}
else //it didnt, let it pass
{
TransactionUtilities.CommitTransaction(action.Transaction);
State.Add(action.Transaction.Id + " comitted: " + action.Transaction.Id);
}
//rereplicate any needed variables
ProcessReReplication(action.Transaction);
}
}
public void AddAction(BaseAction action)
{
Actions.Add(action);
}
public ExecutionEntity(BaseAction action)
{
Actions = new List<BaseAction>();
Actions.Add(action);
}