/
LockedFieldShouldBeReadonly.cs
79 lines (70 loc) · 3.91 KB
/
LockedFieldShouldBeReadonly.cs
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
/*
* SonarAnalyzer for .NET
* Copyright (C) 2015-2023 SonarSource SA
* mailto: contact AT sonarsource DOT com
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 3 of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program; if not, write to the Free Software Foundation,
* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
namespace SonarAnalyzer.Rules.CSharp;
[DiagnosticAnalyzer(LanguageNames.CSharp)]
public sealed class LockedFieldShouldBeReadonly : SonarDiagnosticAnalyzer
{
private const string LockedFieldDiagnosticId = "S2445";
private const string LocalVariableDiagnosticId = "S6507";
private const string MessageFormat = "Do not lock on {0}, use a readonly field instead.";
private static readonly DiagnosticDescriptor LockedFieldRule = DescriptorFactory.Create(LockedFieldDiagnosticId, MessageFormat);
private static readonly DiagnosticDescriptor LocalVariableRule = DescriptorFactory.Create(LocalVariableDiagnosticId, MessageFormat);
public override ImmutableArray<DiagnosticDescriptor> SupportedDiagnostics => ImmutableArray.Create(LockedFieldRule, LocalVariableRule);
protected override void Initialize(SonarAnalysisContext context) =>
context.RegisterNodeAction(CheckLockStatement, SyntaxKind.LockStatement);
private static void CheckLockStatement(SonarSyntaxNodeReportingContext context)
{
var expression = ((LockStatementSyntax)context.Node).Expression?.RemoveParentheses();
if (IsCreation(expression))
{
context.ReportIssue(Diagnostic.Create(LockedFieldRule, expression.GetLocation(), "a new instance because is a no-op"));
}
else
{
var lazySymbol = new Lazy<ISymbol>(() => context.SemanticModel.GetSymbolInfo(expression).Symbol);
if (IsOfTypeString(expression, lazySymbol))
{
context.ReportIssue(Diagnostic.Create(LockedFieldRule, expression.GetLocation(), "strings as they can be interned"));
}
else if (expression is IdentifierNameSyntax && lazySymbol.Value is ILocalSymbol localSymbol)
{
context.ReportIssue(Diagnostic.Create(LocalVariableRule, expression.GetLocation(), $"local variable '{localSymbol.Name}'"));
}
else if (FieldWritable(expression, lazySymbol) is { } field)
{
context.ReportIssue(Diagnostic.Create(LockedFieldRule, expression.GetLocation(), $"writable field '{field.Name}'"));
}
}
}
private static bool IsCreation(ExpressionSyntax expression) =>
expression.IsAnyKind(
SyntaxKind.ObjectCreationExpression,
SyntaxKind.AnonymousObjectCreationExpression,
SyntaxKind.ArrayCreationExpression,
SyntaxKind.ImplicitArrayCreationExpression,
SyntaxKind.QueryExpression);
private static bool IsOfTypeString(ExpressionSyntax expression, Lazy<ISymbol> lazySymbol) =>
expression.IsAnyKind(SyntaxKind.StringLiteralExpression, SyntaxKind.InterpolatedStringExpression)
|| lazySymbol.Value.GetSymbolType().Is(KnownType.System_String);
private static IFieldSymbol FieldWritable(ExpressionSyntax expression, Lazy<ISymbol> lazySymbol) =>
expression.IsAnyKind(SyntaxKind.IdentifierName, SyntaxKind.SimpleMemberAccessExpression) && lazySymbol.Value is IFieldSymbol lockedField && !lockedField.IsReadOnly
? lockedField
: null;
}