private Expression GenerateTryBlock()
{
//
// Declare variables
//
ParameterExpression excepInfo = Expression.Variable(typeof(ExcepInfo), "excepInfo");
ParameterExpression argErr = Expression.Variable(typeof(uint), "argErr");
ParameterExpression hresult = Expression.Variable(typeof(int), "hresult");
List <Expression> tryStatements = new List <Expression>();
if (_keywordArgNames.Length > 0)
{
string[] names = _keywordArgNames.AddFirst(_methodDesc.Name);
tryStatements.Add(
Expression.Assign(
Expression.Field(
DispParamsVariable,
typeof(ComTypes.DISPPARAMS).GetField(nameof(ComTypes.DISPPARAMS.rgdispidNamedArgs))
),
Expression.Call(typeof(UnsafeMethods).GetMethod(nameof(UnsafeMethods.GetIdsOfNamedParameters)),
DispatchObjectVariable,
Expression.Constant(names),
DispIdVariable,
DispIdsOfKeywordArgsPinnedVariable
)
)
);
}
//
// Marshal the arguments to Variants
//
// For a call like this:
// comObj.Foo(100, 101, 102, x=123, z=125)
// DISPPARAMS needs to be setup like this:
// cArgs: 5
// cNamedArgs: 2
// rgArgs: 123, 125, 102, 101, 100
// rgdispidNamedArgs: dispid x, dispid z (the dispids of x and z respectively)
Expression[] parameters = MakeArgumentExpressions();
int reverseIndex = _varEnumSelector.VariantBuilders.Length - 1;
int positionalArgs = _varEnumSelector.VariantBuilders.Length - _keywordArgNames.Length; // args passed by position order and not by name
for (int i = 0; i < _varEnumSelector.VariantBuilders.Length; i++, reverseIndex--)
{
int variantIndex;
if (i >= positionalArgs)
{
// Named arguments are in order at the start of rgArgs
variantIndex = i - positionalArgs;
}
else
{
// Positial arguments are in reverse order at the tail of rgArgs
variantIndex = reverseIndex;
}
VariantBuilder variantBuilder = _varEnumSelector.VariantBuilders[i];
Expression marshal = variantBuilder.InitializeArgumentVariant(
VariantArray.GetStructField(ParamVariantsVariable, variantIndex),
parameters[i + 1]
);
if (marshal != null)
{
tryStatements.Add(marshal);
}
}
//
// Call Invoke
//
ComTypes.INVOKEKIND invokeKind;
if (_methodDesc.IsPropertyPut)
{
if (_methodDesc.IsPropertyPutRef)
{
invokeKind = ComTypes.INVOKEKIND.INVOKE_PROPERTYPUTREF;
}
else
{
invokeKind = ComTypes.INVOKEKIND.INVOKE_PROPERTYPUT;
}
}
else
{
// INVOKE_PROPERTYGET should only be needed for COM objects without typeinfo, where we might have to treat properties as methods
invokeKind = ComTypes.INVOKEKIND.INVOKE_FUNC | ComTypes.INVOKEKIND.INVOKE_PROPERTYGET;
}
MethodCallExpression invoke = Expression.Call(
typeof(UnsafeMethods).GetMethod(nameof(UnsafeMethods.IDispatchInvoke)),
DispatchPointerVariable,
DispIdVariable,
Expression.Constant(invokeKind),
DispParamsVariable,
InvokeResultVariable,
excepInfo,
argErr
);
Expression expr = Expression.Assign(hresult, invoke);
tryStatements.Add(expr);
//
// ComRuntimeHelpers.CheckThrowException(hresult, excepInfo, argErr, ThisParameter);
//
expr = Expression.Call(
typeof(ComRuntimeHelpers).GetMethod(nameof(ComRuntimeHelpers.CheckThrowException)),
hresult,
excepInfo,
argErr,
Expression.Constant(_methodDesc.Name, typeof(string))
);
tryStatements.Add(expr);
//
// _returnValue = (ReturnType)_invokeResult.ToObject();
//
Expression invokeResultObject =
Expression.Call(
InvokeResultVariable,
typeof(Variant).GetMethod(nameof(Variant.ToObject)));
VariantBuilder[] variants = _varEnumSelector.VariantBuilders;
Expression[] parametersForUpdates = MakeArgumentExpressions();
tryStatements.Add(Expression.Assign(ReturnValueVariable, invokeResultObject));
for (int i = 0, n = variants.Length; i < n; i++)
{
Expression updateFromReturn = variants[i].UpdateFromReturn(parametersForUpdates[i + 1]);
if (updateFromReturn != null)
{
tryStatements.Add(updateFromReturn);
}
}
tryStatements.Add(Expression.Empty());
return(Expression.Block(new[] { excepInfo, argErr, hresult }, tryStatements));
}
private Expression MakeIDispatchInvokeTarget()
{
Debug.Assert(_varEnumSelector.VariantBuilders.Length == _totalExplicitArgs);
List <Expression> exprs = new List <Expression>
{
//
// _dispId = ((DispCallable)this).ComMethodDesc.DispId;
//
Expression.Assign(
DispIdVariable,
Expression.Property(_method, typeof(ComMethodDesc).GetProperty(nameof(ComMethodDesc.DispId)))
)
};
//
// _dispParams.rgvararg = RuntimeHelpers.UnsafeMethods.ConvertVariantByrefToPtr(ref _paramVariants._element0)
//
if (_totalExplicitArgs != 0)
{
exprs.Add(
Expression.Assign(
Expression.Field(
DispParamsVariable,
typeof(ComTypes.DISPPARAMS).GetField(nameof(ComTypes.DISPPARAMS.rgvarg))
),
Expression.Call(
typeof(UnsafeMethods).GetMethod(nameof(UnsafeMethods.ConvertVariantByrefToPtr)),
VariantArray.GetStructField(ParamVariantsVariable, 0)
)
)
);
}
//
// _dispParams.cArgs = <number_of_params>;
//
exprs.Add(
Expression.Assign(
Expression.Field(
DispParamsVariable,
typeof(ComTypes.DISPPARAMS).GetField(nameof(ComTypes.DISPPARAMS.cArgs))
),
Expression.Constant(_totalExplicitArgs)
)
);
if (_methodDesc.IsPropertyPut)
{
//
// dispParams.cNamedArgs = 1;
// dispParams.rgdispidNamedArgs = RuntimeHelpers.UnsafeMethods.GetNamedArgsForPropertyPut()
//
exprs.Add(
Expression.Assign(
Expression.Field(
DispParamsVariable,
typeof(ComTypes.DISPPARAMS).GetField(nameof(ComTypes.DISPPARAMS.cNamedArgs))
),
Expression.Constant(1)
)
);
exprs.Add(
Expression.Assign(
PropertyPutDispIdVariable,
Expression.Constant(ComDispIds.DISPID_PROPERTYPUT)
)
);
exprs.Add(
Expression.Assign(
Expression.Field(
DispParamsVariable,
typeof(ComTypes.DISPPARAMS).GetField(nameof(ComTypes.DISPPARAMS.rgdispidNamedArgs))
),
Expression.Call(
typeof(UnsafeMethods).GetMethod(nameof(UnsafeMethods.ConvertInt32ByrefToPtr)),
PropertyPutDispIdVariable
)
)
);
}
else
{
//
// _dispParams.cNamedArgs = N;
//
exprs.Add(
Expression.Assign(
Expression.Field(
DispParamsVariable,
typeof(ComTypes.DISPPARAMS).GetField(nameof(ComTypes.DISPPARAMS.cNamedArgs))
),
Expression.Constant(_keywordArgNames.Length)
)
);
}
//
// _dispatchObject = _dispatch
// _dispatchPointer = Marshal.GetIDispatchForObject(_dispatchObject);
//
exprs.Add(Expression.Assign(DispatchObjectVariable, _dispatch));
exprs.Add(
Expression.Assign(
DispatchPointerVariable,
Expression.Call(
typeof(Marshal).GetMethod(nameof(Marshal.GetIDispatchForObject)),
DispatchObjectVariable
)
)
);
Expression tryStatements = GenerateTryBlock();
Expression finallyStatements = GenerateFinallyBlock();
exprs.Add(Expression.TryFinally(tryStatements, finallyStatements));
exprs.Add(ReturnValueVariable);
var vars = new List <ParameterExpression>();
foreach (VariantBuilder variant in _varEnumSelector.VariantBuilders)
{
if (variant.TempVariable != null)
{
vars.Add(variant.TempVariable);
}
}
return(Expression.Block(vars, exprs));
}