Improve representation of file contents

To improve readability and runtime-efficiency, switch the type to represent file contents from IReadOnlyList<byte> to ReadOnlyMemory<byte>

implement/elm-time/Elm019/Elm019Binaries.cs

@@ -96,7 +96,7 @@ public static Result<string, ElmMakeOk> ElmMake(
             if (cacheEntryFile is not null)
             {
                 var resultFromCache =
-                    System.Text.Json.JsonSerializer.Deserialize<Result<string, ElmMakeOkJsonStructure>>(cacheEntryFile!.ToArray())
+                    System.Text.Json.JsonSerializer.Deserialize<Result<string, ElmMakeOkJsonStructure>>(cacheEntryFile.Value.Span)
                     ?.Map(AsElmMakeOk);
 
                 if (resultFromCache is Result<string, ElmMakeOk>.Ok resultOk)

implement/elm-time/ElmTime/ProcessStore.cs

@@ -111,7 +111,7 @@ public IEnumerable<byte[]> EnumerateSerializedCompositionsRecordsReverse() =>
                 var fileContent = compositionFileStoreReader.GetFileContent(compositionFilePath)!;
 
                 return
-                    Encoding.UTF8.GetString(fileContent as byte[] ?? fileContent.ToArray())
+                    Encoding.UTF8.GetString(fileContent.Value.Span)
                     .Split(new[] { '\r', '\n' }, StringSplitOptions.RemoveEmptyEntries).Reverse()
                     .Select(compositionRecord => Encoding.UTF8.GetBytes(compositionRecord));
             });
@@ -124,7 +124,7 @@ public IEnumerable<byte[]> EnumerateSerializedCompositionsRecordsReverse() =>
 
         var fileContent = reductionFileStoreReader.GetFileContent(filePath);
 
-        if (fileContent == null)
+        if (fileContent is null)
             return null;
 
         try
@@ -135,15 +135,14 @@ public IEnumerable<byte[]> EnumerateSerializedCompositionsRecordsReverse() =>
                 https://github.com/elm-time/elm-time/blob/1cd3f00bdf5a05e9bda479c534b0458b2496393c/implement/PersistentProcess/PersistentProcess.Common/ProcessStore.cs#L183
                 Looking at the files from stores in production, it seems like that caused addition of BOM.
                 */
-                fileContent.Take(3).SequenceEqual(new byte[] { 0xEF, 0xBB, 0xBF })
+                fileContent.Value.Span.StartsWith(new byte[] { 0xEF, 0xBB, 0xBF })
                 ?
                 3
                 :
                 0;
 
             var reductionRecordFromFile =
-                JsonSerializer.Deserialize<ReductionRecordInFile>(
-                    Encoding.UTF8.GetString((fileContent as byte[] ?? fileContent.ToArray()).AsSpan(payloadStartIndex)))!;
+                JsonSerializer.Deserialize<ReductionRecordInFile>(fileContent.Value[payloadStartIndex..].Span)!;
 
             if (reducedCompositionHashBase16 != reductionRecordFromFile.ReducedCompositionHashBase16)
                 throw new Exception("Unexpected content in file " + string.Join("/", filePath) + ", composition hash does not match.");
@@ -156,7 +155,9 @@ public IEnumerable<byte[]> EnumerateSerializedCompositionsRecordsReverse() =>
         }
         catch (Exception e)
         {
-            throw new Exception("Failed to read reduction from file '" + string.Join("/", filePath) + "'.", e);
+            throw new Exception(
+                "Failed to read reduction from file '" + string.Join("/", filePath) + "' (" + fileContent.Value.Length + " bytes)",
+                e);
         }
     }
 

implement/elm-time/Pine/CacheByFileName.cs

@@ -1,6 +1,5 @@
 using System;
 using System.Collections.Immutable;
-using System.Linq;
 
 namespace Pine;
 
@@ -16,7 +15,7 @@ public ReadOnlyMemory<byte> GetOrUpdate(string fileName, Func<ReadOnlyMemory<byt
         var fromCache = FileStore.GetFileContent(entryPath);
 
         if (fromCache is not null)
-            return new ReadOnlyMemory<byte>(fromCache.ToArray());
+            return fromCache;
 
         var file = tryBuild();
 

implement/elm-time/Pine/CommonConversion.cs

@@ -54,12 +54,12 @@ public static ReadOnlyMemory<byte> Deflate(ReadOnlyMemory<byte> input)
         return deflatedStream.ToArray();
     }
 
-    public static ReadOnlyMemory<byte> Inflate(IReadOnlyList<byte> input)
+    public static ReadOnlyMemory<byte> Inflate(ReadOnlyMemory<byte> input)
     {
         using var inflatedStream = new System.IO.MemoryStream();
 
         using var deflateStream = new System.IO.Compression.DeflateStream(
-            new System.IO.MemoryStream(input as byte[] ?? input.ToArray()), System.IO.Compression.CompressionMode.Decompress);
+            new System.IO.MemoryStream(input.ToArray()), System.IO.Compression.CompressionMode.Decompress);
 
         deflateStream.CopyTo(inflatedStream);
 

implement/elm-time/Pine/FileStore.cs

@@ -9,45 +9,45 @@ namespace Pine;
 
 public interface IFileStoreReader
 {
-    IReadOnlyList<byte>? GetFileContent(IImmutableList<string> path);
+    ReadOnlyMemory<byte>? GetFileContent(IImmutableList<string> path);
 
     IEnumerable<IImmutableList<string>> ListFilesInDirectory(IImmutableList<string> directoryPath);
 }
 
 public interface IFileStoreWriter
 {
-    void SetFileContent(IImmutableList<string> path, IReadOnlyList<byte> fileContent);
+    void SetFileContent(IImmutableList<string> path, ReadOnlyMemory<byte> fileContent);
 
     // TODO: Simplify IFileStoreWriter: Do we still need AppendFileContent there?
-    void AppendFileContent(IImmutableList<string> path, IReadOnlyList<byte> fileContent);
+    void AppendFileContent(IImmutableList<string> path, ReadOnlyMemory<byte> fileContent);
 
     void DeleteFile(IImmutableList<string> path);
 }
 
 public record DelegatingFileStoreReader(
-    Func<IImmutableList<string>, IReadOnlyList<byte>?> GetFileContentDelegate,
+    Func<IImmutableList<string>, ReadOnlyMemory<byte>?> GetFileContentDelegate,
     Func<IImmutableList<string>, IEnumerable<IImmutableList<string>>> ListFilesInDirectoryDelegate)
     : IFileStoreReader
 {
-    public IReadOnlyList<byte>? GetFileContent(IImmutableList<string> path) => GetFileContentDelegate(path);
+    public ReadOnlyMemory<byte>? GetFileContent(IImmutableList<string> path) => GetFileContentDelegate(path);
 
     public IEnumerable<IImmutableList<string>> ListFilesInDirectory(IImmutableList<string> directoryPath) =>
         ListFilesInDirectoryDelegate(directoryPath);
 }
 
 public record DelegatingFileStoreWriter(
-    Action<(IImmutableList<string> path, IReadOnlyList<byte> fileContent)> AppendFileContentDelegate,
+    Action<(IImmutableList<string> path, ReadOnlyMemory<byte> fileContent)> AppendFileContentDelegate,
     Action<IImmutableList<string>> DeleteFileDelegate,
-    Action<(IImmutableList<string> path, IReadOnlyList<byte> fileContent)> SetFileContentDelegate)
+    Action<(IImmutableList<string> path, ReadOnlyMemory<byte> fileContent)> SetFileContentDelegate)
     : IFileStoreWriter
 {
-    public void AppendFileContent(IImmutableList<string> path, IReadOnlyList<byte> fileContent) =>
+    public void AppendFileContent(IImmutableList<string> path, ReadOnlyMemory<byte> fileContent) =>
         AppendFileContentDelegate((path, fileContent));
 
     public void DeleteFile(IImmutableList<string> path) =>
         DeleteFileDelegate(path);
 
-    public void SetFileContent(IImmutableList<string> path, IReadOnlyList<byte> fileContent) =>
+    public void SetFileContent(IImmutableList<string> path, ReadOnlyMemory<byte> fileContent) =>
         SetFileContentDelegate((path, fileContent));
 }
 
@@ -89,7 +89,7 @@ private static void EnsureDirectoryExists(string directoryPath)
             Directory.CreateDirectory(directoryPath);
     }
 
-    public void SetFileContent(IImmutableList<string> path, IReadOnlyList<byte> fileContent)
+    public void SetFileContent(IImmutableList<string> path, ReadOnlyMemory<byte> fileContent)
     {
         var filePath = CombinePath(path);
 
@@ -98,10 +98,14 @@ public void SetFileContent(IImmutableList<string> path, IReadOnlyList<byte> file
         if (directoryPath != null)
             EnsureDirectoryExists(directoryPath);
 
-        File.WriteAllBytes(filePath, fileContent as byte[] ?? fileContent.ToArray());
+        using var fileStream = new FileStream(filePath, FileMode.Create, FileAccess.Write);
+
+        fileStream.Write(fileContent.Span);
+
+        fileStream.Flush();
     }
 
-    public void AppendFileContent(IImmutableList<string> path, IReadOnlyList<byte> fileContent)
+    public void AppendFileContent(IImmutableList<string> path, ReadOnlyMemory<byte> fileContent)
     {
         var filePath = CombinePath(path);
 
@@ -112,10 +116,12 @@ public void AppendFileContent(IImmutableList<string> path, IReadOnlyList<byte> f
 
         using var fileStream = new FileStream(filePath, FileMode.Append, FileAccess.Write);
 
-        fileStream.Write(fileContent as byte[] ?? fileContent.ToArray());
+        fileStream.Write(fileContent.Span);
+
+        fileStream.Flush();
     }
 
-    public IReadOnlyList<byte>? GetFileContent(IImmutableList<string> path)
+    public ReadOnlyMemory<byte>? GetFileContent(IImmutableList<string> path)
     {
         var filePath = CombinePath(path);
 
@@ -161,16 +167,16 @@ public FileStoreFromWriterAndReader(IFileStoreWriter writer, IFileStoreReader re
         this.reader = reader;
     }
 
-    public void AppendFileContent(IImmutableList<string> path, IReadOnlyList<byte> fileContent) =>
+    public void AppendFileContent(IImmutableList<string> path, ReadOnlyMemory<byte> fileContent) =>
         writer.AppendFileContent(path, fileContent);
 
     public void DeleteFile(IImmutableList<string> path) =>
         writer.DeleteFile(path);
 
-    public void SetFileContent(IImmutableList<string> path, IReadOnlyList<byte> fileContent) =>
+    public void SetFileContent(IImmutableList<string> path, ReadOnlyMemory<byte> fileContent) =>
         writer.SetFileContent(path, fileContent);
 
-    public IReadOnlyList<byte>? GetFileContent(IImmutableList<string> path) =>
+    public ReadOnlyMemory<byte>? GetFileContent(IImmutableList<string> path) =>
         reader.GetFileContent(path);
 
     public IEnumerable<IImmutableList<string>> ListFilesInDirectory(IImmutableList<string> directoryPath) =>
@@ -187,8 +193,8 @@ public IFileStoreReader Apply(IFileStoreReader fileStoreReader) =>
         WriteOperation.Apply(history, fileStoreReader);
 
     public record WriteOperation(
-        (IImmutableList<string> path, IReadOnlyList<byte> fileContent)? SetFileContent = null,
-        (IImmutableList<string> path, IReadOnlyList<byte> fileContent)? AppendFileContent = null,
+        (IImmutableList<string> path, ReadOnlyMemory<byte> fileContent)? SetFileContent = null,
+        (IImmutableList<string> path, ReadOnlyMemory<byte> fileContent)? AppendFileContent = null,
         IImmutableList<string>? DeleteFile = null)
     {
         public static IFileStoreReader Apply(IEnumerable<WriteOperation> writeOperations, IFileStoreReader fileStoreReader) =>
@@ -235,7 +241,9 @@ public IFileStoreReader Apply(IFileStoreReader previousState)
 
                         if (filePath.SequenceEqual(AppendFileContent.Value.path))
                         {
-                            return (previousFileContent ?? Array.Empty<byte>()).Concat(AppendFileContent.Value.fileContent).ToList();
+                            return CommonConversion.Concat(
+                                (previousFileContent ?? ReadOnlyMemory<byte>.Empty).Span,
+                                AppendFileContent.Value.fileContent.Span);
                         }
 
                         return previousFileContent;
@@ -276,10 +284,10 @@ public IFileStoreReader Apply(IFileStoreReader previousState)
         }
     }
 
-    public void SetFileContent(IImmutableList<string> path, IReadOnlyList<byte> fileContent) =>
+    public void SetFileContent(IImmutableList<string> path, ReadOnlyMemory<byte> fileContent) =>
         history.Enqueue(new WriteOperation { SetFileContent = (path, fileContent) });
 
-    public void AppendFileContent(IImmutableList<string> path, IReadOnlyList<byte> fileContent) =>
+    public void AppendFileContent(IImmutableList<string> path, ReadOnlyMemory<byte> fileContent) =>
         history.Enqueue(new WriteOperation { AppendFileContent = (path, fileContent) });
 
     public void DeleteFile(IImmutableList<string> path) =>
@@ -288,7 +296,7 @@ public void DeleteFile(IImmutableList<string> path) =>
 
 public class EmptyFileStoreReader : IFileStoreReader
 {
-    public IReadOnlyList<byte>? GetFileContent(IImmutableList<string> path) => null;
+    public ReadOnlyMemory<byte>? GetFileContent(IImmutableList<string> path) => null;
 
     public IEnumerable<IImmutableList<string>> ListFilesInDirectory(IImmutableList<string> directoryPath) =>
         ImmutableList<IImmutableList<string>>.Empty;

implement/elm-time/Platform/WebService/PersistentProcessLiveRepresentation.cs

@@ -104,9 +104,9 @@ public static (IImmutableDictionary<IReadOnlyList<string>, ReadOnlyMemory<byte>>
             {
                 var fileContent = fileStoreReader.GetFileContent(filePath);
 
-                if (fileContent != null)
+                if (fileContent is not null)
                 {
-                    filesForProcessRestore[filePath] = fileContent.ToArray();
+                    filesForProcessRestore[filePath] = fileContent.Value;
                 }
 
                 return fileContent;