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#pragma warning disable 659 // overrides AddToHashCodeCombiner instead
/* ****************************************************************************
*
* Copyright (c) Microsoft Corporation. All rights reserved.
*
* This software is subject to the Microsoft Public License (Ms-PL).
* A copy of the license can be found in the license.htm file included
* in this distribution.
*
* You must not remove this notice, or any other, from this software.
*
* ***************************************************************************/
namespace System.Web.Mvc.ExpressionUtil {
using System;
using System.Diagnostics.CodeAnalysis;
using System.Linq.Expressions;
// ConstantExpression fingerprint class
//
// A ConstantExpression might represent a captured local variable, so we can't compile
// the value directly into the cached function. Instead, a placeholder is generated
// and the value is hoisted into a local variables array. This placeholder can then
// be compiled and cached, and the array lookup happens at runtime.
[SuppressMessage("Microsoft.Usage", "CA2218:OverrideGetHashCodeOnOverridingEquals",
Justification = "Overrides AddToHashCodeCombiner() instead.")]
internal sealed class ConstantExpressionFingerprint : ExpressionFingerprint {
private ConstantExpressionFingerprint(ConstantExpression expression)
: base(expression) {
}
public int HoistedLocalsIndex {
get;
private set;
}
internal override void AddToHashCodeCombiner(HashCodeCombiner combiner) {
base.AddToHashCodeCombiner(combiner);
combiner.AddInt32(HoistedLocalsIndex);
}
public static ConstantExpressionFingerprint Create(ConstantExpression expression, ParserContext parserContext) {
ConstantExpressionFingerprint fingerprint = new ConstantExpressionFingerprint(expression) {
HoistedLocalsIndex = parserContext.HoistedValues.Count
};
parserContext.HoistedValues.Add(expression.Value);
return fingerprint;
}
public override bool Equals(object obj) {
ConstantExpressionFingerprint other = obj as ConstantExpressionFingerprint;
if (other == null) {
return false;
}
return (this.HoistedLocalsIndex == other.HoistedLocalsIndex
&& base.Equals(other));
}
public override Expression ToExpression(ParserContext parserContext) {
// (Type) HoistedValues[HoistedLocalsIndex]
BinaryExpression arrayIndex = Expression.ArrayIndex(ParserContext.HoistedValuesParameter, Expression.Constant(HoistedLocalsIndex));
UnaryExpression castExpr = Expression.Convert(arrayIndex, Type);
return castExpr;
}
}
}
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