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DisposeFromDispose.cs
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DisposeFromDispose.cs
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/*
* 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 DisposeFromDispose : SonarDiagnosticAnalyzer
{
internal const string DiagnosticId = "S2952";
private const string MessageFormat = "Move this 'Dispose' call into this class' own 'Dispose' method.";
private const string DisposeMethodName = nameof(IDisposable.Dispose);
private const string DisposeMethodExplicitName = "System.IDisposable.Dispose";
private static readonly DiagnosticDescriptor Rule = DescriptorFactory.Create(DiagnosticId, MessageFormat);
public override ImmutableArray<DiagnosticDescriptor> SupportedDiagnostics { get; } = ImmutableArray.Create(Rule);
protected override void Initialize(SonarAnalysisContext context)
{
context.RegisterNodeAction(
c =>
{
var invocation = (InvocationExpressionSyntax)c.Node;
var languageVersion = c.Compilation.GetLanguageVersion();
if (invocation.Expression is MemberAccessExpressionSyntax memberAccess
&& c.SemanticModel.GetSymbolInfo(memberAccess.Expression).Symbol is IFieldSymbol invocationTarget
&& invocationTarget.IsNonStaticNonPublicDisposableField(languageVersion)
&& IsDisposeMethodCalled(invocation, c.SemanticModel, languageVersion)
&& IsDisposableClassOrStruct(invocationTarget.ContainingType, languageVersion)
&& !IsCalledInsideDispose(invocation, c.SemanticModel))
{
c.ReportIssue(Diagnostic.Create(Rule, memberAccess.Name.GetLocation()));
}
},
SyntaxKind.InvocationExpression);
}
/// <summary>
/// Classes and structs are disposable if they implement the IDisposable interface.
/// Starting C# 8, "ref structs" (which cannot implement an interface) can also be disposable.
/// </summary>
private static bool IsDisposableClassOrStruct(INamedTypeSymbol type, LanguageVersion languageVersion) =>
ImplementsDisposable(type) || type.IsDisposableRefStruct(languageVersion);
private static bool IsCalledInsideDispose(InvocationExpressionSyntax invocation, SemanticModel semanticModel) =>
semanticModel.GetEnclosingSymbol(invocation.SpanStart) is IMethodSymbol enclosingMethodSymbol
&& IsMethodMatchingDisposeMethodName(enclosingMethodSymbol);
/// <summary>
/// Verifies that the invocation is calling the correct Dispose() method on an disposable object.
/// </summary>
/// <remarks>
/// Disposable ref structs do not implement the IDisposable interface and are supported starting C# 8.
/// </remarks>
private static bool IsDisposeMethodCalled(InvocationExpressionSyntax invocation, SemanticModel semanticModel, LanguageVersion languageVersion) =>
semanticModel.GetSymbolInfo(invocation).Symbol is IMethodSymbol methodSymbol
&& KnownMethods.IsIDisposableDispose(methodSymbol)
&& semanticModel.Compilation.SpecialTypeMethod(SpecialType.System_IDisposable, DisposeMethodName) is { } disposeMethodSignature
&& (methodSymbol.Equals(methodSymbol.ContainingType.FindImplementationForInterfaceMember(disposeMethodSignature))
|| methodSymbol.ContainingType.IsDisposableRefStruct(languageVersion));
private static bool IsMethodMatchingDisposeMethodName(IMethodSymbol enclosingMethodSymbol) =>
enclosingMethodSymbol.Name == DisposeMethodName
|| (enclosingMethodSymbol.ExplicitInterfaceImplementations.Any() && enclosingMethodSymbol.Name == DisposeMethodExplicitName);
private static bool ImplementsDisposable(INamedTypeSymbol containingType) =>
containingType.Implements(KnownType.System_IDisposable);
}
}