139 lines
4.9 KiB
C#
139 lines
4.9 KiB
C#
/* ****************************************************************************
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*
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* Copyright (c) Microsoft Corporation.
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*
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* This source code is subject to terms and conditions of the Microsoft Public License. A
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* copy of the license can be found in the License.html file at the root of this distribution. If
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* you cannot locate the Microsoft Public License, please send an email to
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* dlr@microsoft.com. By using this source code in any fashion, you are agreeing to be bound
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* by the terms of the Microsoft Public License.
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*
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* You must not remove this notice, or any other, from this software.
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*
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*
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* ***************************************************************************/
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using System; using Microsoft;
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#if !SILVERLIGHT
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using System.Diagnostics;
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#if CODEPLEX_40
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using System.Dynamic;
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using System.Dynamic.Utils;
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using System.Linq.Expressions;
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using System.Linq.Expressions.Compiler;
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#else
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using Microsoft.Scripting;
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using Microsoft.Scripting.Utils;
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using Microsoft.Linq.Expressions;
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using Microsoft.Linq.Expressions.Compiler;
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#endif
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using System.Runtime.CompilerServices;
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#if !CODEPLEX_40
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using Microsoft.Runtime.CompilerServices;
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#endif
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using System.Runtime.InteropServices;
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using System.Collections.Generic;
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#if CODEPLEX_40
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namespace System.Dynamic {
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#else
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namespace Microsoft.Scripting {
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#endif
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internal static class ComBinderHelpers {
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internal static bool PreferPut(Type type, bool holdsNull) {
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Debug.Assert(type != null);
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if (type.IsValueType || type.IsArray) return true;
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if (type == typeof(String) ||
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type == typeof(DBNull) ||
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holdsNull ||
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type == typeof(System.Reflection.Missing) ||
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type == typeof(CurrencyWrapper)) {
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return true;
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} else {
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return false;
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}
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}
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internal static bool IsByRef(DynamicMetaObject mo) {
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ParameterExpression pe = mo.Expression as ParameterExpression;
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return pe != null && pe.IsByRef;
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}
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internal static bool IsStrongBoxArg(DynamicMetaObject o) {
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Type t = o.LimitType;
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return t.IsGenericType && t.GetGenericTypeDefinition() == typeof(StrongBox<>);
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}
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// this helper prepares arguments for COM binding by transforming ByVal StongBox arguments
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// into ByRef expressions that represent the argument's Value fields.
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internal static bool[] ProcessArgumentsForCom(ref DynamicMetaObject[] args) {
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Debug.Assert(args != null);
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DynamicMetaObject[] newArgs = new DynamicMetaObject[args.Length];
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bool[] isByRefArg = new bool[args.Length];
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for (int i = 0; i < args.Length; i++) {
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DynamicMetaObject curArgument = args[i];
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// set new arg infos to their original values or set default ones
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// we will do this fixup early so that we can assume we always have
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// arginfos in COM binder.
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if (IsByRef(curArgument)) {
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newArgs[i] = curArgument;
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isByRefArg[i] = true;
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} else {
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if (IsStrongBoxArg(curArgument)) {
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var restrictions = curArgument.Restrictions.Merge(
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GetTypeRestrictionForDynamicMetaObject(curArgument)
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);
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// we have restricted this argument to LimitType so we can convert and conversion will be trivial cast.
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Expression boxedValueAccessor = Expression.Field(
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Helpers.Convert(
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curArgument.Expression,
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curArgument.LimitType
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),
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curArgument.LimitType.GetField("Value")
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);
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IStrongBox value = curArgument.Value as IStrongBox;
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object boxedValue = value != null ? value.Value : null;
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newArgs[i] = new DynamicMetaObject(
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boxedValueAccessor,
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restrictions,
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boxedValue
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);
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isByRefArg[i] = true;
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} else {
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newArgs[i] = curArgument;
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isByRefArg[i] = false;
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}
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}
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}
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args = newArgs;
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return isByRefArg;
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}
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internal static BindingRestrictions GetTypeRestrictionForDynamicMetaObject(DynamicMetaObject obj) {
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if (obj.Value == null && obj.HasValue) {
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//If the meta object holds a null value, create an instance restriction for checking null
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return BindingRestrictions.GetInstanceRestriction(obj.Expression, null);
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}
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return BindingRestrictions.GetTypeRestriction(obj.Expression, obj.LimitType);
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}
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}
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}
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#endif
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