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C#: Desugar property patterns that uses member access syntax.

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This commit is contained in:
Michael Nebel
2022-01-24 14:21:32 +01:00
parent 26d9848fca
commit 83e7fae578
1 changed files with 81 additions and 5 deletions
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86
csharp/extractor/Semmle.Extraction.CSharp/Entities/Expressions/Patterns/PropertyPattern.cs
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@@ -1,3 +1,5 @@
using System;
using System.Collections.Generic;
using Microsoft.CodeAnalysis.CSharp.Syntax;
using Semmle.Extraction.Kinds;
using Semmle.Extraction.Entities;
@@ -10,17 +12,91 @@ namespace Semmle.Extraction.CSharp.Entities.Expressions
base(new ExpressionInfo(cx, null, cx.CreateLocation(pp.GetLocation()), ExprKind.PROPERTY_PATTERN, parent, child, false, null))
{
child = 0;
var trapFile = cx.TrapWriter.Writer;
foreach (var sub in pp.Subpatterns)
{
var p = Expressions.Pattern.Create(cx, sub.Pattern, this, child++);
if (sub.NameColon is null)
if (sub.ExpressionColon is null)
{
Context.ModelError(sub, "Expected to find 'Name:' in pattern.");
Context.ModelError(sub, "Expected to find 'Expression:' in pattern.");
continue;
}
trapFile.exprorstmt_name(p, sub.NameColon.Name.ToString());
MakeExpressions(cx, this, sub, child++);
}
}
private class AccessStep
{
public readonly string Identifier;
public readonly Microsoft.CodeAnalysis.Location Location;
public AccessStep(string identifier, Microsoft.CodeAnalysis.Location location)
{
Identifier = identifier;
Location = location;
}
}
private class AccessStepPack
{
public readonly List<AccessStep> Prefix = new List<AccessStep>();
public AccessStep Last { get; private set; }
public AccessStepPack Add(string identifier, Microsoft.CodeAnalysis.Location location)
{
Prefix.Add(Last);
Last = new AccessStep(identifier, location);
return this;
}
public AccessStepPack(string identifier, Microsoft.CodeAnalysis.Location location)
{
Last = new AccessStep(identifier, location);
}
}
private static AccessStepPack GetAccessStepPack(ExpressionSyntax syntax)
{
switch (syntax)
{
case MemberAccessExpressionSyntax memberAccess:
return GetAccessStepPack(memberAccess.Expression).Add(memberAccess.Name.Identifier.ValueText, memberAccess.Name.Identifier.GetLocation());
case IdentifierNameSyntax identifier:
return new AccessStepPack(identifier.Identifier.Text, identifier.GetLocation());
default:
throw new InternalError(syntax, "Unexpected expression syntax in property patterns.");
}
}
private static AccessStepPack GetAccessStepPack(BaseExpressionColonSyntax syntax)
{
switch (syntax)
{
case NameColonSyntax ncs:
return new AccessStepPack(ncs.Name.ToString(), ncs.Name.GetLocation());
case ExpressionColonSyntax ecs:
return GetAccessStepPack(ecs.Expression);
default:
throw new InternalError(syntax, "Unsupported expression colon in property pattern.");
};
}
private static Expression CreateSyntheticExp(Context cx, Microsoft.CodeAnalysis.Location location, IExpressionParentEntity parent, int child) =>
new Expression(new ExpressionInfo(cx, null, cx.CreateLocation(location), ExprKind.PROPERTY_PATTERN, parent, child, false, null));
private static void MakeExpressions(Context cx, IExpressionParentEntity parent, SubpatternSyntax syntax, int child)
{
var trapFile = cx.TrapWriter.Writer;
var pack = GetAccessStepPack(syntax.ExpressionColon!);
foreach (var step in pack.Prefix)
{
var exp = CreateSyntheticExp(cx, step.Location, parent, child);
trapFile.exprorstmt_name(exp, step.Identifier);
parent = exp;
child = 0;
}
var p = Expressions.Pattern.Create(cx, syntax.Pattern, parent, child);
trapFile.exprorstmt_name(p, pack.Last.Identifier);
}
}
}