Refactored some functions

LightlessSync/FileCache/FileCacheManager.cs

@@ -18,6 +18,7 @@ public sealed class FileCacheManager : IHostedService
     public const string PenumbraPrefix = "{penumbra}";
     private const int FileCacheVersion = 1;
     private const string FileCacheVersionHeaderPrefix = "#lightless-file-cache-version:";
+    private readonly SemaphoreSlim _fileWriteSemaphore = new(1, 1);
     private readonly LightlessConfigService _configService;
     private readonly LightlessMediator _lightlessMediator;
     private readonly string _csvPath;
@@ -169,27 +170,53 @@ public sealed class FileCacheManager : IHostedService
         return CreateFileCacheEntity(fi, prefixedPath);
     }
 
-    public List<FileCacheEntity> GetAllFileCaches() => _fileCaches.Values.SelectMany(v => v.Values.Where(e => e != null)).ToList();
+    public List<FileCacheEntity> GetAllFileCaches() => [.. _fileCaches.Values.SelectMany(v => v.Values.Where(e => e != null))];
 
     public List<FileCacheEntity> GetAllFileCachesByHash(string hash, bool ignoreCacheEntries = false, bool validate = true)
     {
-        List<FileCacheEntity> output = [];
-        if (_fileCaches.TryGetValue(hash, out var fileCacheEntities))
+        var output = new List<FileCacheEntity>();
+
+        if (!_fileCaches.TryGetValue(hash, out var fileCacheEntities))
+            return output;
+
+        foreach (var fileCache in fileCacheEntities.Values
+                     .Where(c => !ignoreCacheEntries || !c.IsCacheEntry))
         {
-            foreach (var fileCache in fileCacheEntities.Values.Where(c => !ignoreCacheEntries || !c.IsCacheEntry).ToList())
+            if (!validate)
             {
-                if (!validate)
-                {
-                    output.Add(fileCache);
-                }
-                else
-                {
-                    var validated = GetValidatedFileCache(fileCache);
-                    if (validated != null)
-                    {
-                        output.Add(validated);
-                    }
-                }
+                output.Add(fileCache);
+                continue;
+            }
+
+            var validated = GetValidatedFileCache(fileCache);
+            if (validated != null)
+                output.Add(validated);
+        }
+
+        return output;
+    }
+
+    public async Task<List<FileCacheEntity>> GetAllFileCachesByHashAsync(string hash, bool ignoreCacheEntries = false, bool validate = true,CancellationToken token = default)
+    {
+        var output = new List<FileCacheEntity>();
+
+        if (!_fileCaches.TryGetValue(hash, out var fileCacheEntities))
+            return output;
+
+        foreach (var fileCache in fileCacheEntities.Values.Where(c => !ignoreCacheEntries || !c.IsCacheEntry))
+        {
+            token.ThrowIfCancellationRequested();
+
+            if (!validate)
+            {
+                output.Add(fileCache);
+            }
+            else
+            {
+                var validated = await GetValidatedFileCacheAsync(fileCache, token).ConfigureAwait(false);
+
+                if (validated != null)
+                    output.Add(validated);
             }
         }
 
@@ -479,6 +506,44 @@ public sealed class FileCacheManager : IHostedService
         }
     }
 
+    public async Task WriteOutFullCsvAsync(CancellationToken cancellationToken = default)
+    {
+        await _fileWriteSemaphore.WaitAsync(cancellationToken).ConfigureAwait(false);
+
+        try
+        {
+            var sb = new StringBuilder();
+            sb.AppendLine(BuildVersionHeader());
+
+            foreach (var entry in _fileCaches.Values
+                         .SelectMany(k => k.Values)
+                         .OrderBy(f => f.PrefixedFilePath, StringComparer.OrdinalIgnoreCase))
+            {
+                sb.AppendLine(entry.CsvEntry);
+            }
+
+            if (File.Exists(_csvPath))
+            {
+                File.Copy(_csvPath, CsvBakPath, overwrite: true);
+            }
+
+            try
+            {
+                await File.WriteAllTextAsync(_csvPath, sb.ToString(), cancellationToken).ConfigureAwait(false);
+
+                File.Delete(CsvBakPath);
+            }
+            catch
+            {
+                await File.WriteAllTextAsync(CsvBakPath, sb.ToString(), cancellationToken).ConfigureAwait(false);
+            }
+        }
+        finally
+        {
+            _fileWriteSemaphore.Release();
+        }
+    }
+
     private void EnsureCsvHeaderLocked()
     {
         if (!File.Exists(_csvPath))
@@ -601,6 +666,13 @@ public sealed class FileCacheManager : IHostedService
         return resultingFileCache;
     }
 
+    private async Task<FileCacheEntity?> GetValidatedFileCacheAsync(FileCacheEntity fileCache, CancellationToken token = default)
+    {
+        var resultingFileCache = ReplacePathPrefixes(fileCache);
+        resultingFileCache = await ValidateAsync(resultingFileCache, token).ConfigureAwait(false);
+        return resultingFileCache;
+    }
+
     private FileCacheEntity ReplacePathPrefixes(FileCacheEntity fileCache)
     {
         if (fileCache.PrefixedFilePath.StartsWith(PenumbraPrefix, StringComparison.OrdinalIgnoreCase))
@@ -623,6 +695,7 @@ public sealed class FileCacheManager : IHostedService
             RemoveHashedFile(fileCache.Hash, fileCache.PrefixedFilePath);
             return null;
         }
+
         var file = new FileInfo(fileCache.ResolvedFilepath);
         if (!file.Exists)
         {
@@ -630,7 +703,8 @@ public sealed class FileCacheManager : IHostedService
             return null;
         }
 
-        if (!string.Equals(file.LastWriteTimeUtc.Ticks.ToString(CultureInfo.InvariantCulture), fileCache.LastModifiedDateTicks, StringComparison.Ordinal))
+        var lastWriteTicks = file.LastWriteTimeUtc.Ticks.ToString(CultureInfo.InvariantCulture);
+        if (!string.Equals(lastWriteTicks, fileCache.LastModifiedDateTicks, StringComparison.Ordinal))
         {
             UpdateHashedFile(fileCache);
         }
@@ -638,6 +712,33 @@ public sealed class FileCacheManager : IHostedService
         return fileCache;
     }
 
+    private async Task<FileCacheEntity?> ValidateAsync(FileCacheEntity fileCache, CancellationToken token)
+    {
+        if (string.IsNullOrWhiteSpace(fileCache.ResolvedFilepath))
+        {
+            _logger.LogWarning("FileCacheEntity has empty ResolvedFilepath for hash {hash}, prefixed path {prefixed}", fileCache.Hash, fileCache.PrefixedFilePath);
+            RemoveHashedFile(fileCache.Hash, fileCache.PrefixedFilePath);
+            return null;
+        }
+
+        return await Task.Run(() =>
+        {
+            var file = new FileInfo(fileCache.ResolvedFilepath);
+            if (!file.Exists)
+            {
+                RemoveHashedFile(fileCache.Hash, fileCache.PrefixedFilePath);
+                return null;
+            }
+
+            if (!string.Equals(file.LastWriteTimeUtc.Ticks.ToString(CultureInfo.InvariantCulture), fileCache.LastModifiedDateTicks, StringComparison.Ordinal))
+            {
+                UpdateHashedFile(fileCache);
+            }
+
+            return fileCache;
+        }, token).ConfigureAwait(false);
+    }
+
     public async Task StartAsync(CancellationToken cancellationToken)
     {
         _logger.LogInformation("Starting FileCacheManager");
@@ -811,7 +912,7 @@ public sealed class FileCacheManager : IHostedService
 
             if (rewriteRequired)
             {
-                WriteOutFullCsv();
+                await WriteOutFullCsvAsync(cancellationToken).ConfigureAwait(false);
             }
         }
 
@@ -822,7 +923,7 @@ public sealed class FileCacheManager : IHostedService
 
     public async Task StopAsync(CancellationToken cancellationToken)
     {
-        WriteOutFullCsv();
+        await WriteOutFullCsvAsync(cancellationToken).ConfigureAwait(false);
         await Task.CompletedTask.ConfigureAwait(false);
     }
 }