/* ****************************************************************************
*
* Copyright (c) Microsoft Corporation.
*
* This source code is subject to terms and conditions of the Microsoft Public License. A
* copy of the license can be found in the License.html file at the root of this distribution. If
* you cannot locate the Microsoft Public License, please send an email to
* dlr@microsoft.com. By using this source code in any fashion, you are agreeing to be bound
* by the terms of the Microsoft Public License.
*
* You must not remove this notice, or any other, from this software.
*
*
* ***************************************************************************/
#if !SILVERLIGHT // ComObject
#if !CLR2
using System.Linq.Expressions;
#else
using Microsoft.Scripting.Ast;
#endif
using System;
using System.Diagnostics;
using System.Runtime.InteropServices;
namespace Microsoft.Scripting.ComInterop{
/// <summary>
/// VariantBuilder handles packaging of arguments into a Variant for a call to IDispatch.Invoke
/// </summary>
internal class VariantBuilder {
private MemberExpression _variant;
private readonly ArgBuilder _argBuilder;
private readonly VarEnum _targetComType;
internal ParameterExpression TempVariable { get; private set; }
internal VariantBuilder(VarEnum targetComType, ArgBuilder builder) {
_targetComType = targetComType;
_argBuilder = builder;
}
internal bool IsByRef {
get { return (_targetComType & VarEnum.VT_BYREF) != 0; }
}
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;
}
}
private static Expression Release(Expression pUnk) {
return Expression.Call(typeof(UnsafeMethods).GetMethod("IUnknownReleaseNotZero"), pUnk);
}
internal Expression Clear() {
if (IsByRef) {
if (_argBuilder is StringArgBuilder) {
Debug.Assert(TempVariable != null);
return Expression.Call(typeof(Marshal).GetMethod("FreeBSTR"), TempVariable);
} else if (_argBuilder is DispatchArgBuilder) {
Debug.Assert(TempVariable != null);
return Release(TempVariable);
} else if (_argBuilder is UnknownArgBuilder) {
Debug.Assert(TempVariable != null);
return Release(TempVariable);
} else if (_argBuilder is VariantArgBuilder) {
Debug.Assert(TempVariable != null);
return Expression.Call(TempVariable, typeof(Variant).GetMethod("Clear"));
}
return null;
}
switch (_targetComType) {
case VarEnum.VT_EMPTY:
case VarEnum.VT_NULL:
return null;
case VarEnum.VT_BSTR:
case VarEnum.VT_UNKNOWN:
case VarEnum.VT_DISPATCH:
case VarEnum.VT_ARRAY:
case VarEnum.VT_RECORD:
case VarEnum.VT_VARIANT:
// paramVariants._elementN.Clear()
return Expression.Call(_variant, typeof(Variant).GetMethod("Clear"));
default:
Debug.Assert(Variant.IsPrimitiveType(_targetComType), "Unexpected VarEnum");
return null;
}
}
internal Expression UpdateFromReturn(Expression parameter) {
if (TempVariable == null) {
return null;
}
return Expression.Assign(
parameter,
Helpers.Convert(
_argBuilder.UnmarshalFromRef(TempVariable),
parameter.Type
)
);
}
}
}
#endif
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