review comments

Sources/NIOFileSystem/FileChunks.swift

@@ -115,8 +115,8 @@ where
  let nioThrowingAsyncSequence = NIOThrowingAsyncSequenceProducer.makeSequence(
  elementType: ByteBuffer.self,
  backPressureStrategy: NIOAsyncSequenceProducerBackPressureStrategies.HighLowWatermark(
- lowWatermark: 4,
- highWatermark: 8
+ lowWatermark: lowWatermark,
+ highWatermark: highWatermark
  ),
  finishOnDeinit: false,
  delegate: producer
@@ -451,11 +451,6 @@ private struct ProducerState: Sendable {
  }
  }
 
- internal enum RangeUpdateOutcome {
- case moreToRead
- case cannotReadMore
- }
-
  mutating func activeThreadPool() -> NIOThreadPool? {
  switch self.state {
  case .producing(let producingState), .pausedProducing(let producingState):
@@ -468,7 +463,9 @@ private struct ProducerState: Sendable {
  mutating func fileReadingState() -> Result<(FileDescriptor, Range<Int64>?)?, FileSystemError> {
  switch self.state {
  case .producing(let producingState), .pausedProducing(let producingState):
- guard let descriptor = producingState.handle.descriptorIfAvailable() else {
+ if let descriptor = producingState.handle.descriptorIfAvailable() {
+ return .success((descriptor, producingState.range))
+ } else {
  let error = FileSystemError(
  code: .closed,
  message: "Cannot read from closed file ('\(producingState.handle.path)').",
@@ -477,8 +474,6 @@ private struct ProducerState: Sendable {
  )
  return .failure(error)
  }
-
- return .success((descriptor, producingState.range))
  case .done:
  return .success(nil)
  }
@@ -521,10 +516,15 @@ private struct ProducerState: Sendable {
 
 @available(macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0, *)
 extension ProducerState.Producing {
+ internal enum RangeUpdateOutcome {
+ case moreToRead
+ case cannotReadMore
+ }
+
  /// Updates the range (the offsets to read from and up to) to reflect the number of bytes which have been read.
  /// - Parameter count: The number of bytes which have been read.
- /// - Returns: Returns `True` if there are no remaining bytes to read, `False` otherwise.
- mutating func updateRangeWithReadBytes(_ count: Int) -> ProducerState.RangeUpdateOutcome {
+ /// - Returns: Returns `.moreToRead` if there are no remaining bytes to read, `.cannotReadMore` otherwise.
+ mutating func updateRangeWithReadBytes(_ count: Int) -> RangeUpdateOutcome {
  guard let currentRange = self.range else {
  // we are reading the whole file, just keep going
  return .moreToRead
@@ -540,9 +540,6 @@ extension ProducerState.Producing {
 
  // update range, we are not done
  self.range = newLowerBound..<currentRange.upperBound
- if currentRange.upperBound - newLowerBound < 1 {
- fatalError("here \(newLowerBound) \(currentRange.upperBound)")
- }
  return .moreToRead
  }
 }