MegaBites-AI/Windows-powershell

1// Copyright (c) Microsoft Corporation.2// Licensed under the MIT License.3 4#nullable enable5 6using System.Buffers;7using System.IO;8using System.Threading;9using System.Threading.Tasks;10 11namespace System.Management.Automation;12 13/// <summary>14/// Represents the transfer of bytes from one <see cref="Stream" /> to another15/// asynchronously.16/// </summary>17internal sealed class AsyncByteStreamTransfer : IDisposable18{19    private const int DefaultBufferSize = 1024;20 21    private readonly BytePipe _bytePipe;22 23    private readonly BytePipe _destinationPipe;24 25    private readonly Memory<byte> _buffer;26 27    private readonly CancellationTokenSource _cts = new();28 29    private Task? _readToBufferTask;30 31    public AsyncByteStreamTransfer(32        BytePipe bytePipe,33        BytePipe destinationPipe)34    {35        _bytePipe = bytePipe;36        _destinationPipe = destinationPipe;37        _buffer = new byte[DefaultBufferSize];38    }39 40    public Task EOF => _readToBufferTask ?? Task.CompletedTask;41 42    public void BeginReadChunks()43    {44        _readToBufferTask = Task.Run(ReadBufferAsync);45    }46 47    public void Dispose() => _cts.Cancel();48 49    private async Task ReadBufferAsync()50    {51        Stream stream;52        Stream? destinationStream = null;53        try54        {55            stream = await _bytePipe.GetStream(_cts.Token);56            destinationStream = await _destinationPipe.GetStream(_cts.Token);57 58            while (true)59            {60                int bytesRead;61                bytesRead = await stream.ReadAsync(_buffer, _cts.Token);62                if (bytesRead is 0)63                {64                    break;65                }66 67                destinationStream.Write(_buffer.Span.Slice(0, bytesRead));68            }69        }70        catch (IOException)71        {72            return;73        }74        catch (OperationCanceledException)75        {76            return;77        }78        finally79        {80            destinationStream?.Close();81        }82    }83}84