internal Expression InitializeArgumentVariant(MemberExpression variant, Expression parameter)
{
//NOTE: we must remember our variant
//the reason is that argument order does not map exactly to the order of variants for invoke
//and when we are doing clean-up we must be sure we are cleaning the variant we have initialized.
_variant = variant;
if (IsByRef)
{
// temp = argument
// paramVariants._elementN.SetAsByrefT(ref temp)
Debug.Assert(TempVariable == null);
var argExpr = _argBuilder.MarshalToRef(parameter);
TempVariable = Expression.Variable(argExpr.Type, null);
return(Expression.Block(
Expression.Assign(TempVariable, argExpr),
Expression.Call(
variant,
Variant.GetByrefSetter(_targetComType & ~VarEnum.VT_BYREF),
TempVariable
)
));
}
Expression argument = _argBuilder.Marshal(parameter);
// we are forced to special case ConvertibleArgBuilder since it does not have
// a corresponding _targetComType.
if (_argBuilder is ConvertibleArgBuilder)
{
return(Expression.Call(
variant,
typeof(Variant).GetMethod("SetAsIConvertible"),
argument
));
}
if (Variant.IsPrimitiveType(_targetComType) ||
(_targetComType == VarEnum.VT_DISPATCH) ||
(_targetComType == VarEnum.VT_UNKNOWN) ||
(_targetComType == VarEnum.VT_VARIANT) ||
(_targetComType == VarEnum.VT_RECORD) ||
(_targetComType == VarEnum.VT_ARRAY))
{
// paramVariants._elementN.AsT = (cast)argN
return(Expression.Assign(
Expression.Property(
variant,
Variant.GetAccessor(_targetComType)
),
argument
));
}
switch (_targetComType)
{
case VarEnum.VT_EMPTY:
return(null);
case VarEnum.VT_NULL:
// paramVariants._elementN.SetAsNull();
return(Expression.Call(variant, typeof(Variant).GetMethod("SetAsNull")));
default:
Debug.Assert(false, "Unexpected VarEnum");
return(null);
}
}