使用 Roslyn 分析器检查源代码行是否超出行长度的最佳方法是什么？

Question

我想对代码线长度执行一些硬限制。

我应该使用什么Roslyn的API？

为每个语法节点注册操作并检查节点的位置似乎不是最有效的方法。

Answer 1

不完美的解决方案：

[DiagnosticAnalyzer(LanguageNames.CSharp)]
public sealed class LineMaxLengthAnalyzer : DiagnosticAnalyzer
{
    public const int LineMaxLength = 150;
    public const string DiagnosticId = nameof(LineMaxLengthAnalyzer);

    private static readonly LocalizableString Title = new LocalizableResourceString(
        nameof(Resources.LineMaxLengthAnalyzerTitle), Resources.ResourceManager, typeof(Resources));
    private static readonly LocalizableString MessageFormat = new LocalizableResourceString(
        nameof(Resources.LineMaxLengthAnalyzerMessageFormat), Resources.ResourceManager, typeof(Resources));
    private static readonly LocalizableString Description = new LocalizableResourceString(
        nameof(Resources.LineMaxLengthAnalyzerDescription), Resources.ResourceManager, typeof(Resources));
    private const string Category = "Readability";

    private static readonly DiagnosticDescriptor Rule = new DiagnosticDescriptor(
        DiagnosticId, Title, MessageFormat, Category, DiagnosticSeverity.Error, isEnabledByDefault: true, description: Description);

    public override ImmutableArray<DiagnosticDescriptor> SupportedDiagnostics { get; } = ImmutableArray.Create(Rule);

    public override void Initialize(AnalysisContext context)
    {
        context.ConfigureGeneratedCodeAnalysis(GeneratedCodeAnalysisFlags.None);
        context.EnableConcurrentExecution();

        var nodeTypes = Enum.GetValues(typeof(SyntaxKind)).Cast<SyntaxKind>().ToArray();
        context.RegisterSyntaxTreeAction(VerifyLines);
    }

    private void VerifyLines(SyntaxTreeAnalysisContext context)
    {
        var text = context.Tree.GetText();
        text.Lines.Where(line => line.End - line.Start + 1 > LineMaxLength).ToList()
            .ForEach(line =>
            {
                var location = Location.Create(context.Tree, line.Span);
                var diagnostic = Diagnostic.Create(Rule, location, LineMaxLength);
                context.ReportDiagnostic(diagnostic);
            });
    }
}

Answer 2

一种简单的方法可能是注册语法树，然后立即在语法树上调用 GetText() ；从那里您可以直接查看文本的行，并且至少找到“长”行，因为您可以通过这种方式直接获取行跨度和长度。您仍然可能需要过滤掉长字符串文字之类的东西。