Add Async RAR and more

[adamhathcock]

Part of #992

[Copilot]

Copilot encountered an error and was unable to review this pull request. You can try again by re-requesting a review.

[Copilot]

Pull Request Overview

Copilot reviewed 26 out of 26 changed files in this pull request and generated 58 comments.

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[Copilot]

Duplicate assignment of _isDisposed = true. The field is already set to true on line 103, making this second assignment redundant and potentially confusing.

Suggested change

_isDisposed = true;

[Copilot]

ArrayPool.Shared.Rent() may return an array larger than requested. The code should track the actual WinSize separately and ensure only the required portion is used, or clear the entire rented array to avoid using uninitialized memory from the pool.

Suggested change

	var NewWindow = Fragmented ? null : ArrayPool<byte>.Shared.Rent((int)WinSize);
	var NewWindow = Fragmented ? null : ArrayPool<byte>.Shared.Rent((int)WinSize);
	if (NewWindow != null)
	{
	// Clear only the portion of the array that will be used.
	Array.Clear(NewWindow, 0, (int)WinSize);
	}

[Copilot]

The rented array is not used. The code rents an array but then calls base.ReadAsync(buffer, ...) with the original buffer, making the array allocation wasteful. Either use the rented array for the read operation or remove the unnecessary allocation.

Suggested change

	var array = System.Buffers.ArrayPool<byte>.Shared.Rent(buffer.Length);
	try
	{
	var result = await base.ReadAsync(buffer, cancellationToken).ConfigureAwait(false);
	if (result != 0)
	{
	currentCrc = RarCRC.CheckCrc(currentCrc, buffer.Span, 0, result);
	}
	else if (
	!disableCRC
	&& GetCrc() != BitConverter.ToUInt32(readStream.CurrentCrc, 0)
	&& buffer.Length != 0
	)
	{
	// NOTE: we use the last FileHeader in a multipart volume to check CRC
	throw new InvalidFormatException("file crc mismatch");
	}
	return result;
	}
	finally
	{
	System.Buffers.ArrayPool<byte>.Shared.Return(array);
	}
	var result = await base.ReadAsync(buffer, cancellationToken).ConfigureAwait(false);
	if (result != 0)
	{
	currentCrc = RarCRC.CheckCrc(currentCrc, buffer.Span, 0, result);
	}
	else if (
	!disableCRC
	&& GetCrc() != BitConverter.ToUInt32(readStream.CurrentCrc, 0)
	&& buffer.Length != 0
	)
	{
	// NOTE: we use the last FileHeader in a multipart volume to check CRC
	throw new InvalidFormatException("file crc mismatch");
	}
	return result;

[Copilot]

These 'if' statements can be combined.

Suggested change

	if (Inp.InAddr > ReadTop - 25)
	{
	if (!await UnpReadBufAsync(cancellationToken).ConfigureAwait(false))
	{
	return false;
	}
	if (Inp.InAddr > ReadTop - 25 && !await UnpReadBufAsync(cancellationToken).ConfigureAwait(false))
	{
	return false;

[Copilot]

These 'if' statements can be combined.

Suggested change

	if (Inp.InAddr > ReadTop - 5)
	{
	if (!await UnpReadBufAsync(cancellationToken).ConfigureAwait(false))
	{
	return false;
	}
	if (Inp.InAddr > ReadTop - 5 && !await UnpReadBufAsync(cancellationToken).ConfigureAwait(false))
	{
	return false;

[Copilot]

The expression 'A == false' can be simplified to '!A'.

Suggested change

	&& fltj.NextWindow == false
	&& !fltj.NextWindow

[Copilot]

This variable is manually disposed in a finally block - consider a C# using statement as a preferable resource management technique.

[Copilot]

Both branches of this 'if' statement write to the same variable - consider using '?' to express intent better.

Suggested change

	RarStream stream;
	if (IsRarV3)
	{
	stream = new RarStream(
	archive.UnpackV1.Value,
	FileHeader,
	new MultiVolumeReadOnlyStream(Parts.Cast<RarFilePart>(), archive)
	);
	}
	else
	{
	stream = new RarStream(
	archive.UnpackV2017.Value,
	FileHeader,
	new MultiVolumeReadOnlyStream(Parts.Cast<RarFilePart>(), archive)
	);
	}
	RarStream stream = new RarStream(
	IsRarV3 ? archive.UnpackV1.Value : archive.UnpackV2017.Value,
	FileHeader,
	new MultiVolumeReadOnlyStream(Parts.Cast<RarFilePart>(), archive)
	);

[adamhathcock]

@copilot figure out why the windows tests fail

[Copilot]

@adamhathcock I've opened a new pull request, #1000, to work on those changes. Once the pull request is ready, I'll request review from you.