public bool PrtPopState(bool isPopStatement)
{
Debug.Assert(stateStack.TopOfStack != null);
//pop stack
stateStack.PopStackFrame();
if (stateStack.TopOfStack == null)
{
if (isPopStatement)
{
throw new PrtInvalidPopStatement();
}
//TODO : Handle the monitor machine case separately for the halt event
else if (eventValue.IsEqual(PrtValue.HaltEvent))
{
throw new PrtUnhandledEventException();
}
else
{
currentStatus = PrtMachineStatus.Halted;
}
}
return(currentStatus == PrtMachineStatus.Halted);
}
public override void PrtEnqueueEvent(PrtValue e, PrtValue arg, PrtMachine source)
{
int numOfStepsTaken = 0;
// set the currentTrigger and currentPayload fields
// so that we can reuse the common functions
currentPayload = arg.Clone();
currentTrigger = e;
PrtValue currEventValue;
PrtFun currAction;
bool hasMoreWork = false;
try
{
Start:
switch (nextSMOperation)
{
case PrtNextStatemachineOperation.EntryOperation:
goto DoEntry;
case PrtNextStatemachineOperation.HandleEventOperation:
goto DoHandleEvent;
}
DoEntry:
if (invertedFunStack.TopOfStack == null)
{
//Trace: entered state
if (CurrentState.entryFun.IsAnonFun)
{
PrtPushFunStackFrame(CurrentState.entryFun, CurrentState.entryFun.CreateLocals(currentPayload));
}
else
{
PrtPushFunStackFrame(CurrentState.entryFun, CurrentState.entryFun.CreateLocals());
}
}
//invoke the function
invertedFunStack.TopOfStack.fun.Execute(stateImpl, this);
goto CheckFunLastOperation;
DoAction:
currAction = PrtFindActionHandler(eventValue);
if (currAction == PrtCommonFunctions.IgnoreFun)
{
//Trace: Performed ignore action for the event
currentTrigger = PrtValue.NullValue;
currentPayload = PrtValue.NullValue;
}
else
{
if (invertedFunStack.TopOfStack == null)
{
//Trace: executed the action handler for event
PrtPushFunStackFrame(currAction, currAction.CreateLocals(currentPayload));
}
//invoke the action handler
invertedFunStack.TopOfStack.fun.Execute(stateImpl, this);
}
goto CheckFunLastOperation;
CheckFunLastOperation:
switch (continuation.reason)
{
case PrtContinuationReason.Goto:
{
stateExitReason = PrtStateExitReason.OnGotoStatement;
PrtExecuteExitFunction();
goto CheckFunLastOperation;
}
case PrtContinuationReason.Raise:
{
nextSMOperation = PrtNextStatemachineOperation.HandleEventOperation;
hasMoreWork = true;
goto Finish;
}
case PrtContinuationReason.Return:
{
switch (stateExitReason)
{
case PrtStateExitReason.NotExit:
{
nextSMOperation = PrtNextStatemachineOperation.HandleEventOperation;
hasMoreWork = false;
goto Finish;
}
case PrtStateExitReason.OnGotoStatement:
{
PrtChangeState(destOfGoto);
nextSMOperation = PrtNextStatemachineOperation.EntryOperation;
stateExitReason = PrtStateExitReason.NotExit;
hasMoreWork = true;
goto Finish;
}
case PrtStateExitReason.OnUnhandledEvent:
{
hasMoreWork = !PrtPopState(false);
nextSMOperation = PrtNextStatemachineOperation.HandleEventOperation;
stateExitReason = PrtStateExitReason.NotExit;
goto Finish;
}
case PrtStateExitReason.OnTransition:
{
stateExitReason = PrtStateExitReason.OnTransitionAfterExit;
PrtExecuteTransitionFun(eventValue);
goto CheckFunLastOperation;
}
case PrtStateExitReason.OnTransitionAfterExit:
{
PrtChangeState(CurrentState.transitions[eventValue].gotoState);
hasMoreWork = true;
nextSMOperation = PrtNextStatemachineOperation.EntryOperation;
stateExitReason = PrtStateExitReason.NotExit;
goto Finish;
}
default:
{
Debug.Assert(false, "Unexpected value for exit reason");
goto Finish;
}
}
}
default:
{
Debug.Assert(false, "Unexpected value for continuation reason");
goto Finish;
}
}
DoHandleEvent:
if (!currentTrigger.IsEqual(PrtValue.NullValue))
{
currEventValue = currentTrigger;
currentTrigger = PrtValue.NullValue;
}
else
{
currEventValue = eventValue;
}
if (PrtIsTransitionPresent(currEventValue))
{
stateExitReason = PrtStateExitReason.OnTransition;
eventValue = currEventValue;
PrtExecuteExitFunction();
goto CheckFunLastOperation;
}
else if (PrtIsActionInstalled(currEventValue))
{
goto DoAction;
}
else
{
stateExitReason = PrtStateExitReason.OnUnhandledEvent;
eventValue = currEventValue;
PrtExecuteExitFunction();
goto CheckFunLastOperation;
}
Finish:
if (hasMoreWork)
{
if (numOfStepsTaken > 100000)
{
throw new PrtInfiniteRaiseLoop("Infinite loop in monitor");
}
else
{
numOfStepsTaken++;
goto Start;
}
}
else
{
return;
}
}
catch (PrtException ex)
{
stateImpl.Exception = ex;
}
}
