Massively improved write speed

Author: d2dyno1

SecureFolderFS.Core/Chunks/Implementation/BaseCleartextChunk.cs

@@ -36,7 +36,7 @@ public virtual void CopyFrom(ReadOnlySpan<byte> sourceBuffer, int offset, ref in
 
             var readCount = Math.Min(buffer.Length - offset, sourceBuffer.Length - positionInBuffer);
             var destination = buffer.AsSpan(offset, readCount);
-            sourceBuffer.Slice(0, readCount).CopyTo(destination);
+            sourceBuffer.Slice(positionInBuffer, readCount).CopyTo(destination);
             positionInBuffer += readCount;
 
             ActualLength = Math.Max(ActualLength, readCount + offset);

SecureFolderFS.Core/FileSystem/FileSystemAdapter/Dokan/Callback/Implementation/ReadFileCallback.cs

@@ -44,7 +44,18 @@ public NtStatus ReadFile(string fileName, IntPtr buffer, uint bufferLength, out
                 }
 
                 // Read file
-                bytesRead = StreamHelpers.ReadToIntPtrBuffer(fileHandle.CleartextFileStream, buffer, bufferLength, offset);
+                if (opened)
+                {
+                    bytesRead = StreamHelpers.ReadToIntPtrBuffer(fileHandle.CleartextFileStream, buffer, bufferLength, offset);
+                }
+                else
+                {
+                    lock (fileHandle.CleartextFileStream)
+                    {
+                        bytesRead = StreamHelpers.ReadToIntPtrBuffer(fileHandle.CleartextFileStream, buffer, bufferLength, offset);
+                    }
+                }
+                
                 return DokanResult.Success;
             }
             catch (PathTooLongException)

SecureFolderFS.Core/FileSystem/FileSystemAdapter/Dokan/Callback/Implementation/WriteFileCallback.cs

@@ -48,15 +48,28 @@ public NtStatus WriteFile(string fileName, IntPtr buffer, uint bufferLength, out
                 if (handles.GetHandle(contextHandle) is not FileHandle fileHandle)
                 {
                     // Invalid handle...
-                    contextHandle = handles.OpenHandleToFile(ciphertextPath, FileMode.Open, System.IO.FileAccess.ReadWrite,
+                    contextHandle = handles.OpenHandleToFile(ciphertextPath, appendToFile ? FileMode.Append : FileMode.Open, System.IO.FileAccess.ReadWrite,
                         FileShare.Read, FileOptions.None);
                     fileHandle = (FileHandle)handles.GetHandle(contextHandle);
 
                     opened = true;
                 }
 
+                var correctOffset = !appendToFile ? offset : fileHandle.CleartextFileStream.Length;
+
                 // Write file
-                bytesWritten = StreamHelpers.WriteFromIntPtrBuffer(fileHandle.CleartextFileStream, buffer, bufferLength, appendToFile ? fileHandle.CleartextFileStream.Length : offset);
+                if (opened)
+                {
+                    bytesWritten = StreamHelpers.WriteFromIntPtrBuffer(fileHandle.CleartextFileStream, buffer, bufferLength, correctOffset);
+                }
+                else
+                {
+                    lock (fileHandle.CleartextFileStream)
+                    {
+                        bytesWritten = StreamHelpers.WriteFromIntPtrBuffer(fileHandle.CleartextFileStream, buffer, bufferLength, correctOffset);
+                    }
+                }
+
                 return DokanResult.Success;
             }
             catch (PathTooLongException)
@@ -69,6 +82,11 @@ public NtStatus WriteFile(string fileName, IntPtr buffer, uint bufferLength, out
                 bytesWritten = 0;
                 return NtStatus.CrcError;
             }
+            catch (UnavailableStreamException)
+            {
+                bytesWritten = 0;
+                return DokanResult.InvalidHandle;
+            }
             catch (Exception ex)
             {
                 _ = ex;

SecureFolderFS.Core/Helpers/StreamHelpers.cs

@@ -1,7 +1,6 @@
 using System;
 using System.IO;
 using System.Text;
-using System.Runtime.InteropServices;
 using System.Security.Cryptography;
 using SecureFolderFS.Sdk.Streams;
 using System.Runtime.CompilerServices;
@@ -11,56 +10,32 @@ namespace SecureFolderFS.Core.Helpers
     internal static class StreamHelpers
     {
         [MethodImpl(MethodImplOptions.Synchronized)]
-        public static int ReadToIntPtrBuffer(IBaseFileStream baseFileStream, IntPtr nativeBuffer, uint bufferLength, long offset)
+        public unsafe static int ReadToIntPtrBuffer(IBaseFileStream baseFileStream, IntPtr nativeBuffer, uint bufferLength, long offset)
         {
             if (offset >= baseFileStream.Length)
             {
                 return Constants.IO.FILE_EOF;
             }
             else
             {
-                var readBuffer = new byte[Constants.IO.READ_BUFFER_SIZE];
-                var position = 0;
                 baseFileStream.Position = offset;
 
-                do
-                {
-                    var remaining = (int)bufferLength - position;
-                    var read = baseFileStream.Read(readBuffer, 0, Math.Min(readBuffer.Length, remaining));
+                var nativeBufferSpan = new Span<byte>(nativeBuffer.ToPointer(), (int)bufferLength);
+                baseFileStream.Read(nativeBufferSpan);
 
-                    if (read == Constants.IO.FILE_EOF)
-                    {
-                        return position; // Reached End-of-File EOF
-                    }
-                    else
-                    {
-                        Marshal.Copy(readBuffer, 0, nativeBuffer + position, read);
-                        position += read;
-                    }
-                } while (position < bufferLength);
-
-                return position;
+                return (int)bufferLength;
             }
         }
 
         [MethodImpl(MethodImplOptions.Synchronized)]
         public unsafe static int WriteFromIntPtrBuffer(IBaseFileStream baseFileStream, IntPtr nativeBuffer, uint bufferLength, long offset)
         {
-            var position = 0;
-
             baseFileStream.Position = offset;
-            do
-            {
-                var remaining = bufferLength - position;
-                var writeLength = (int)Math.Min(remaining, Constants.IO.WRITE_BUFFER_SIZE);
-                var writeBuffer = new Span<byte>((nativeBuffer + position).ToPointer(), writeLength);
-
-                baseFileStream.Write(writeBuffer.Slice(0, writeLength));
 
-                position += writeLength;
-            } while (position < bufferLength);
+            var nativeBufferSpan = new ReadOnlySpan<byte>(nativeBuffer.ToPointer(), (int)bufferLength);
+            baseFileStream.Write(nativeBufferSpan);
 
-            return position;
+            return (int)bufferLength;
         }
 
         public static void WriteToStream(Stream sourceStream, Stream destinationStream)

SecureFolderFS.Core/Security/ContentCrypt/FileContent/AesGcmContentCryptor.cs

@@ -32,7 +32,7 @@ protected override ICiphertextChunk EncryptChunk(CleartextAesGcmChunk cleartextC
             secureRandom.GetBytes(fullCiphertextChunkSpan.Slice(0, CiphertextAesGcmChunk.CHUNK_NONCE_SIZE));
 
             // Big Endian chunk number and file header nonce
-            var beChunkNumberWithFileHeaderNonce = new byte[sizeof(long) + fileHeader.Nonce.Length]; // TODO: Rent array? (and in xchacha20 too)
+            var beChunkNumberWithFileHeaderNonce = new byte[sizeof(long) + fileHeader.Nonce.Length];
             var beChunkNumber = BitConverter.GetBytes(chunkNumber).AsBigEndian();
 
             Buffer.BlockCopy(beChunkNumber, 0, beChunkNumberWithFileHeaderNonce, 0, beChunkNumber.Length);