/
ArgumentNullCheckAnalysis.cs
137 lines (119 loc) · 5.44 KB
/
ArgumentNullCheckAnalysis.cs
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// Copyright (c) Josef Pihrt and Contributors. Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
using System;
using System.Threading;
using Microsoft.CodeAnalysis;
using Microsoft.CodeAnalysis.CSharp.Syntax;
using Roslynator.CSharp.Syntax;
namespace Roslynator.CSharp
{
internal readonly struct ArgumentNullCheckAnalysis
{
private ArgumentNullCheckAnalysis(ArgumentNullCheckStyle style, bool success)
{
Style = style;
Success = success;
}
public ArgumentNullCheckStyle Style { get; }
public bool Success { get; }
public static ArgumentNullCheckAnalysis Create(
StatementSyntax statement,
SemanticModel semanticModel,
CancellationToken cancellationToken = default)
{
return Create(statement, semanticModel, name: null, cancellationToken);
}
public static ArgumentNullCheckAnalysis Create(
StatementSyntax statement,
SemanticModel semanticModel,
string name,
CancellationToken cancellationToken = default)
{
if (statement is IfStatementSyntax ifStatement)
{
var style = ArgumentNullCheckStyle.None;
var success = false;
if (ifStatement.SingleNonBlockStatementOrDefault() is ThrowStatementSyntax throwStatement
&& throwStatement.Expression is ObjectCreationExpressionSyntax objectCreation)
{
NullCheckExpressionInfo nullCheck = SyntaxInfo.NullCheckExpressionInfo(
ifStatement.Condition,
semanticModel,
NullCheckStyles.EqualsToNull | NullCheckStyles.IsNull,
cancellationToken: cancellationToken);
if (nullCheck.Success)
{
style = ArgumentNullCheckStyle.IfStatement;
if (name is null
|| (nullCheck.Expression is IdentifierNameSyntax identifierName
&& string.Equals(name, identifierName.Identifier.ValueText, StringComparison.Ordinal)))
{
if (semanticModel
.GetSymbol(objectCreation, cancellationToken)?
.ContainingType?
.HasMetadataName(MetadataNames.System_ArgumentNullException) == true)
{
success = true;
}
}
}
}
return new ArgumentNullCheckAnalysis(style, success);
}
else
{
return CreateFromArgumentNullExceptionThrowIfNullCheck(statement, semanticModel, name, cancellationToken);
}
}
private static ArgumentNullCheckAnalysis CreateFromArgumentNullExceptionThrowIfNullCheck(
StatementSyntax statement,
SemanticModel semanticModel,
string name,
CancellationToken cancellationToken)
{
var style = ArgumentNullCheckStyle.None;
var success = false;
if (statement is ExpressionStatementSyntax expressionStatement)
{
SimpleMemberInvocationStatementInfo invocationInfo = SyntaxInfo.SimpleMemberInvocationStatementInfo(expressionStatement);
if (invocationInfo.Success
&& string.Equals(invocationInfo.NameText, "ThrowIfNull", StringComparison.Ordinal)
&& semanticModel
.GetSymbol(invocationInfo.InvocationExpression, cancellationToken)?
.ContainingType?
.HasMetadataName(MetadataNames.System_ArgumentNullException) == true)
{
style = ArgumentNullCheckStyle.ThrowIfNullMethod;
if (name is null
|| (invocationInfo.Arguments.SingleOrDefault(shouldThrow: false)?.Expression is IdentifierNameSyntax identifierName
&& string.Equals(name, identifierName.Identifier.ValueText, StringComparison.Ordinal)))
{
success = true;
}
}
}
return new ArgumentNullCheckAnalysis(style, success);
}
public static bool IsArgumentNullExceptionThrowIfNullCheck(
StatementSyntax statement,
SemanticModel semanticModel,
CancellationToken cancellationToken = default)
{
return CreateFromArgumentNullExceptionThrowIfNullCheck(statement, semanticModel, null, cancellationToken).Success;
}
public static bool IsArgumentNullCheck(
StatementSyntax statement,
SemanticModel semanticModel,
CancellationToken cancellationToken = default)
{
return IsArgumentNullCheck(statement, semanticModel, name: null, cancellationToken);
}
public static bool IsArgumentNullCheck(
StatementSyntax statement,
SemanticModel semanticModel,
string name,
CancellationToken cancellationToken = default)
{
return Create(statement, semanticModel, name, cancellationToken).Success;
}
}
}