/// <summary>
/// Take the topmost arguments down to the ARG_MARKER_STRING, pop them off, and then
/// put them back again in reversed order so a function can read them in normal order.
/// Note that if this is an indirect call, it will also consume the thing just under
/// the ARG_MARKER, since that's expected to be the delegate or KOSDelegate that we already
/// read and pulled the needed information from.
/// <param name="cpu">the cpu we are running on, fur stack manipulation purposes</param>
/// <param name="direct">need to know if this was a direct or indirect call. If indirect,
/// then that means it also needs to consume the indirect reference off the stack just under
/// the args</param>
/// </summary>
public static void ReverseStackArgs(ICpu cpu, bool direct)
{
List <object> args = new List <object>();
object arg = cpu.PopValueArgument();
while (cpu.GetArgumentStackSize() > 0 && arg.GetType() != ArgMarkerType)
{
args.Add(arg);
// It's important to dereference with PopValue, not using PopArgumentStack, because the function
// being called might not even be able to see the variable in scope anyway.
// In other words, if calling a function like so:
// declare foo to 3.
// myfunc(foo).
// The code inside myfunc needs to see that as being identical to just saying:
// myfunc(3).
// It has to be unaware of the fact that the name of the argument was 'foo'. It just needs to
// see the contents that were inside foo.
arg = cpu.PopValueArgument();
}
if (!direct)
{
cpu.PopArgumentStack(); // throw away the delegate or KOSDelegate info - we already snarfed it by now.
}
// Push the arg marker back on again.
cpu.PushArgumentStack(new KOSArgMarkerType());
// Push the arguments back on again, which will invert their order:
foreach (object item in args)
{
cpu.PushArgumentStack(item);
}
}
public void Invoke(ICpu cpu)
{
var args = new List <object>();
var paramArrayArgs = new List <Structure>();
// Will be true iff the lastmost parameter of the delegate is using the C# 'param' keyword and thus
// expects the remainder of the arguments marshalled together into one array object.
bool isParamArrayArg = false;
CpuUtility.ReverseStackArgs(cpu, false);
for (int i = 0; i < delInfo.Parameters.Length; ++i)
{
DelegateParameter paramInfo = delInfo.Parameters[i];
object arg = cpu.PopValueArgument();
Type argType = arg.GetType();
isParamArrayArg = i == delInfo.Parameters.Length - 1 && delInfo.Parameters[i].IsParams;
if (arg != null && arg.GetType() == CpuUtility.ArgMarkerType)
{
if (isParamArrayArg)
{
break; // with param arguments, you want to consume everything to the arg bottom - it's normal.
}
else
{
throw new KOSArgumentMismatchException(delInfo.Parameters.Length, delInfo.Parameters.Length - (i + 1));
}
}
// Either the expected type of this one parameter, or if it's a 'param' array as the last arg, then
// the expected type of that array's elements:
Type paramType = (paramInfo.IsParams ? paramInfo.ParameterType.GetElementType() : paramInfo.ParameterType);
// Parameter type-safe checking:
bool inheritable = paramType.IsAssignableFrom(argType);
if (!inheritable)
{
bool castError = false;
// If it's not directly assignable to the expected type, maybe it's "castable" to it:
try
{
arg = Convert.ChangeType(arg, Type.GetTypeCode(paramType));
}
catch (InvalidCastException)
{
throw new KOSCastException(argType, paramType);
}
catch (FormatException)
{
castError = true;
}
if (castError)
{
throw new Exception(string.Format("Argument {0}({1}) to method {2} should be {3} instead of {4}.", (delInfo.Parameters.Length - i), arg, delInfo.Name, paramType.Name, argType));
}
}
if (isParamArrayArg)
{
paramArrayArgs.Add(Structure.FromPrimitiveWithAssert(arg));
--i; // keep hitting the last item in the param list again and again until a forced break because of arg bottom marker.
}
else
{
args.Add(Structure.FromPrimitiveWithAssert(arg));
}
}
if (isParamArrayArg)
{
// collect the param array args that were at the end into the one single
// array item that will be sent to the method when invoked:
args.Add(paramArrayArgs.ToArray());
}
// Consume the bottom marker under the args, which had better be
// immediately under the args we just popped, or the count was off.
if (!isParamArrayArg) // A param array arg will have already consumed the arg bottom mark.
{
bool foundArgMarker = false;
int numExtraArgs = 0;
while (cpu.GetArgumentStackSize() > 0 && !foundArgMarker)
{
object marker = cpu.PopValueArgument();
if (marker != null && marker.GetType() == CpuUtility.ArgMarkerType)
{
foundArgMarker = true;
}
else
{
++numExtraArgs;
}
}
if (numExtraArgs > 0)
{
throw new KOSArgumentMismatchException(delInfo.Parameters.Length, delInfo.Parameters.Length + numExtraArgs);
}
}
// Delegate.DynamicInvoke expects a null, rather than an array of zero length, when
// there are no arguments to pass:
object[] argArray = (args.Count > 0) ? args.ToArray() : null;
object val = call(argArray);
if (delInfo.ReturnType == typeof(void))
{
value = ScalarValue.Create(0);
}
else
{
value = Structure.FromPrimitiveWithAssert(val);
}
}