/// <summary>
/// Walking through the exception handler chain to find the proper
/// exception handler. Also notify the observers who are keen on being
/// notified when an exception is happening.
/// </summary>
/// <param name="context">Exception context</param>
public void HandleFirstHandException(ExceptionContext context)
{
ExceptionHandler exceHandler = ExceptionTable.FindExceptionHandler(context);
if (exceHandler != null)
{
TargetHandler = exceHandler;
}
Context = context;
IsStackUnwinding = true;
// Anybody wants to be notified before going to exception handler
// or stack unwinding?
foreach (IFirstHandExceptionObserver observer in Observers)
{
observer.Notify(context);
}
}
/// <summary>
/// Walk through chained exception registration instances to find out
/// the corresponding exception handler. Returns null if cannot find
/// the handler.
/// </summary>
/// <param name="context">Exception context</param>
/// <returns></returns>
public ExceptionHandler FindExceptionHandler(ExceptionContext context)
{
int regIndex = IndexOf(context.codeBlockId, context.functionScope, context.classScope);
Validity.Assert(regIndex != ProtoCore.DSASM.Constants.kInvalidIndex);
ExceptionRegistration registration = Registrations[regIndex];
int pc = context.pc;
while (true)
{
int handlerIndex;
if (registration.HandleIt(pc, context.typeUID, out handlerIndex))
{
Validity.Assert(handlerIndex != ProtoCore.DSASM.Constants.kInvalidIndex);
return registration.Handlers[handlerIndex];
}
else
{
int parentIndex = registration.ParentIndex;
if (parentIndex == ProtoCore.DSASM.Constants.kInvalidIndex)
{
break;
}
else
{
pc = registration.LastPc;
registration = Registrations[parentIndex];
}
}
}
return null;
}