C# Attribute 實戰：構建自動化代碼統計分析工具

編輯：關於C語言

利用 C# 特性將元數據嵌入程序集，配合反射實現零侵入式代碼統計分析：方法數統計、開發者貢獻度、Bug 標記追蹤、IL 代碼查看。本文提供完整架構設計與核心代碼。

為什麼選 Attribute？

編譯時嵌入元數據：不像註釋被丟棄，Attribute 進入 Assembly Metadata，運行時可反射讀取
類型安全：編譯器驗證參數類型，避免字符串解析錯誤
零運行時開銷：僅在反射讀取時消耗性能，正常執行零影響
工具鏈友好：IDE、靜態分析、CI/CD 皆可識別

核心 Attribute 定義

獨立類庫 CodeAnalytics.Attributes，供業務項目引用：

[AttributeUsage(AttributeTargets.Class | AttributeTargets.Method, AllowMultiple = false)]
public sealed class CreatorAttribute : Attribute {
    public string Creator { get; }
    public string CreateDate { get; }
    public CreatorAttribute(string creator, string createDate) {
        Creator = creator;
        CreateDate = createDate;
    }
}

[AttributeUsage(AttributeTargets.Class | AttributeTargets.Method, AllowMultiple = true)]
public sealed class ReviewerAttribute : Attribute {
    public string Reviewer { get; }
    public string ReviewDate { get; }
    public ReviewerAttribute(string reviewer, string reviewDate) {
        Reviewer = reviewer;
        ReviewDate = reviewDate;
    }
}

[AttributeUsage(AttributeTargets.Method, AllowMultiple = false)]
public sealed class BugAttribute : Attribute {
    public bool HasBug { get; }
    public string BugDate { get; }
    public BugAttribute(bool hasBug, string bugDate) {
        HasBug = hasBug;
        BugDate = bugDate;
    }
}

業務代碼標註示例

[Creator("join", "2024-01-15")]
public class OrderService {
    [Creator("join", "2024-01-15")]
    [Reviewer("alice", "2024-01-16")]
    [Bug(false, "")]
    public void CreateOrder(OrderDto dto) { /* ... */ }

    [Creator("bob", "2024-01-18")]
    [Reviewer("alice", "2024-01-19")]
    [Reviewer("charlie", "2024-01-20")]
    [Bug(true, "2024-01-21")] // 曾有 Bug
    public void CancelOrder(int orderId) { /* ... */ }
}

統計分析引擎核心

public sealed class AssemblyAnalyzer {
    public AnalysisReport Analyze(string assemblyPath) {
        var asm = Assembly.LoadFrom(assemblyPath);
        var report = new AnalysisReport { AssemblyName = asm.GetName().Name };

        foreach (var type in asm.GetTypes()) {
            var typeCreator = type.GetCustomAttribute();
            foreach (var method in type.GetMethods(BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.Static)) {
                if (method.IsSpecialName) continue; // 跳過屬性 get/set、構造函數等

                var creator = method.GetCustomAttribute() ?? typeCreator;
                var reviewers = method.GetCustomAttributes().ToList();
                var bug = method.GetCustomAttribute();

                report.Methods.Add(new MethodStat {
                    FullName = $"{type.FullName}.{method.Name}",
                    Creator = creator?.Creator ?? "Unknown",
                    CreateDate = creator?.CreateDate,
                    Reviewers = reviewers.Select(r => r.Reviewer).ToList(),
                    HasBug = bug?.HasBug ?? false,
                    BugDate = bug?.BugDate,
                    ILCode = GetILCode(method) // 輔助功能
                });
            }
        }
        return report;
    }

    private string GetILCode(MethodInfo method) {
        var body = method.GetMethodBody();
        if (body == null) return "N/A (Abstract/Extern)";
        var il = body.GetILAsByteArray();
        return string.Join(" ", il.Select(b => b.ToString("X2")));
    }
}

public class AnalysisReport {
    public string AssemblyName { get; set; }
    public List Methods { get; } = new List();
    public int TotalMethods => Methods.Count;
    public int BugMethods => Methods.Count(m => m.HasBug);
    public Dictionary CreatorStats => Methods
        .GroupBy(m => m.Creator)
        .ToDictionary(g => g.Key, g => g.Count());
    public Dictionary ReviewerStats => Methods
        .SelectMany(m => m.Reviewers)
        .GroupBy(r => r)
        .ToDictionary(g => g.Key, g => g.Count());
}

public class MethodStat {
    public string FullName { get; set; }
    public string Creator { get; set; }
    public string CreateDate { get; set; }
    public List Reviewers { get; set; } = new List();
    public bool HasBug { get; set; }
    public string BugDate { get; set; }
    public string ILCode { get; set; }
}