C#でファイルをキャッシュするプログラム(Dictionary-TSV)

using System.ComponentModel.DataAnnotations;

class FileCacheEntity
{
    public string Path { get; set; } = "";
    public long Length { get; set; } = -1;
    public DateTime LastUpdate { get; set; }
    public string GUID { get; set; }

    public FileCacheEntity()
    {
        LastUpdate = DateTime.Now;
        GUID = Guid.NewGuid().ToString("N");
    }

    override public string ToString()
    {
        string result = "";

        result += Path + "\t";
        result += Length.ToString() + "\t";
        result += LastUpdate.ToString("yyyy/MM/dd HH:mm:ss") + "\t";
        result += GUID;

        return result;
    }
    public void Parse(string str)
    {
        string[] array = str.Split("\t");

        Path = array[0];
        Length = long.Parse(array[1]);
        LastUpdate = DateTime.Parse(array[2]);
        GUID = array[3];

        /*
            Console.WriteLine($"Path: {Path}");
            Console.WriteLine($"Length: {Length}");
            Console.WriteLine($"LastUpdate: {LastUpdate}");
            Console.WriteLine($"GUID: {GUID}");
        */
    }
}

using Microsoft.VisualBasic;

class FileCacheManager : IDisposable
{
    string _tsvPath;
    string _cacheDir;
    Dictionary<string, FileCacheEntity> _dic;

    public FileCacheManager(string tsvPath = @".\FileCache01.tsv", string cacheDir = @".\.cache")
    {
        _tsvPath = tsvPath;
        _cacheDir = cacheDir;

        if (!Directory.Exists(_cacheDir))
            Directory.CreateDirectory(_cacheDir);

        _dic = new();

        if (!File.Exists(_tsvPath)) return;

        using (StreamReader reader = File.OpenText(_tsvPath))
        {
            while(!reader.EndOfStream)
            {
                string? line = reader.ReadLine();
                if (line is null) continue;
                FileCacheEntity fce = new();
                fce.Parse(line);
                _dic[fce.Path] = fce;
            }
        }
    }
    public void Dispose()
    {
        if (File.Exists(_tsvPath))
            File.Delete(_tsvPath);

        using (StreamWriter writer = new (_tsvPath))
        {
            foreach(FileCacheEntity fec in _dic.Values)
            {
                writer.WriteLine(fec.ToString());
            }
        }   
    }
    public MemoryStream Get(string path)
    {
        MemoryStream ms = new();
        if (_dic.ContainsKey(path))
        {
            var e = _dic[path];
            string cachePath = Path.Join(_cacheDir, e.GUID);
            if (File.Exists(cachePath))
            {
                using FileStream fs = new (cachePath, FileMode.Open, FileAccess.Read);
                fs.CopyTo(ms);
                ms.Seek(0, SeekOrigin.Begin);
                return ms;
            }
        }
        return ms;
    }
    public void Set(string path, MemoryStream ms)
    {
        FileInfo fi = new (path);
        FileCacheEntity fce = new()
        {
            Path = path,
            Length = fi.Length,
            LastUpdate = fi.LastWriteTime,
        };

        string cachePath = Path.Join(_cacheDir, fce.GUID);
        if (File.Exists(cachePath))
            File.Delete(cachePath);
        ms.Seek(0, SeekOrigin.Begin);
        using FileStream fs = new (cachePath, FileMode.CreateNew, FileAccess.Write);
        ms.CopyTo(fs);

        _dic[path] = fce;
    }
}

using System.Diagnostics;

class Program
{
    public static void Main()
    {
        const string targetFile = @"H:\Pictures\202410081107.PNG";

        using var fcm = new FileCacheManager();

        Stopwatch sw = new();
        sw.Start();
        using MemoryStream ms = fcm.Get(targetFile);

        if (ms.Length > 0)
        {
            sw.Stop();
            Console.WriteLine($"キャッシュに有り サイズ:{ms.Length}Byte 時間:{sw.ElapsedMilliseconds}ms");
        }
        else
        {
            using FileStream fs = new (targetFile, FileMode.Open, FileAccess.Read);
            ms.Seek(0, SeekOrigin.Begin);
            fs.CopyTo(ms);
            fcm.Set(targetFile, ms);
            sw.Stop();
            Console.WriteLine($"キャッシュに無し サイズ:{ms.Length}Byte 時間:{sw.ElapsedMilliseconds}ms");
        }

        /*
        FileInfo fi = new (targetFile);

        FileCacheEntity fce = new FileCacheEntity()
        {
            Path = targetFile,
            LastUpdate = fi.LastWriteTime,
            Length = fi.Length,
        };

        string str = fce.ToString();
        Console.WriteLine(str);
        fce.Parse(str);
        */
    }
}

キャッシュに無し サイズ:6955Byte 時間:32ms

キャッシュに有り サイズ:6955Byte 時間:1ms