jellyfin/Jellyfin.Api/Helpers/ProgressiveFileStream.cs
2021-11-27 03:23:46 +01:00

182 lines
5.8 KiB
C#

using System;
using System.Diagnostics;
using System.IO;
using System.Threading;
using System.Threading.Tasks;
using Jellyfin.Api.Models.PlaybackDtos;
using MediaBrowser.Model.IO;
namespace Jellyfin.Api.Helpers
{
/// <summary>
/// A progressive file stream for transferring transcoded files as they are written to.
/// </summary>
public class ProgressiveFileStream : Stream
{
private readonly Stream _stream;
private readonly TranscodingJobDto? _job;
private readonly TranscodingJobHelper? _transcodingJobHelper;
private readonly int _timeoutMs;
private bool _disposed;
/// <summary>
/// Initializes a new instance of the <see cref="ProgressiveFileStream"/> class.
/// </summary>
/// <param name="filePath">The path to the transcoded file.</param>
/// <param name="job">The transcoding job information.</param>
/// <param name="transcodingJobHelper">The transcoding job helper.</param>
/// <param name="timeoutMs">The timeout duration in milliseconds.</param>
public ProgressiveFileStream(string filePath, TranscodingJobDto? job, TranscodingJobHelper transcodingJobHelper, int timeoutMs = 30000)
{
_job = job;
_transcodingJobHelper = transcodingJobHelper;
_timeoutMs = timeoutMs;
_stream = new FileStream(filePath, FileMode.Open, FileAccess.Read, FileShare.ReadWrite, IODefaults.FileStreamBufferSize, FileOptions.Asynchronous | FileOptions.SequentialScan);
}
/// <summary>
/// Initializes a new instance of the <see cref="ProgressiveFileStream"/> class.
/// </summary>
/// <param name="stream">The stream to progressively copy.</param>
/// <param name="timeoutMs">The timeout duration in milliseconds.</param>
public ProgressiveFileStream(Stream stream, int timeoutMs = 30000)
{
_job = null;
_transcodingJobHelper = null;
_timeoutMs = timeoutMs;
_stream = stream;
}
/// <inheritdoc />
public override bool CanRead => _stream.CanRead;
/// <inheritdoc />
public override bool CanSeek => false;
/// <inheritdoc />
public override bool CanWrite => false;
/// <inheritdoc />
public override long Length => throw new NotSupportedException();
/// <inheritdoc />
public override long Position
{
get => throw new NotSupportedException();
set => throw new NotSupportedException();
}
/// <inheritdoc />
public override void Flush()
{
// Not supported
}
/// <inheritdoc />
public override int Read(byte[] buffer, int offset, int count)
=> Read(buffer.AsSpan(offset, count));
/// <inheritdoc />
public override int Read(Span<byte> buffer)
{
int totalBytesRead = 0;
var stopwatch = Stopwatch.StartNew();
while (KeepReading(stopwatch.ElapsedMilliseconds))
{
totalBytesRead += _stream.Read(buffer);
if (totalBytesRead > 0)
{
break;
}
Thread.Sleep(50);
}
UpdateBytesWritten(totalBytesRead);
return totalBytesRead;
}
/// <inheritdoc />
public override async Task<int> ReadAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken)
=> await ReadAsync(buffer.AsMemory(offset, count), cancellationToken).ConfigureAwait(false);
/// <inheritdoc />
public override async ValueTask<int> ReadAsync(Memory<byte> buffer, CancellationToken cancellationToken = default)
{
int totalBytesRead = 0;
var stopwatch = Stopwatch.StartNew();
while (KeepReading(stopwatch.ElapsedMilliseconds))
{
totalBytesRead += await _stream.ReadAsync(buffer, cancellationToken).ConfigureAwait(false);
if (totalBytesRead > 0)
{
break;
}
await Task.Delay(50, cancellationToken).ConfigureAwait(false);
}
UpdateBytesWritten(totalBytesRead);
return totalBytesRead;
}
/// <inheritdoc />
public override long Seek(long offset, SeekOrigin origin)
=> throw new NotSupportedException();
/// <inheritdoc />
public override void SetLength(long value)
=> throw new NotSupportedException();
/// <inheritdoc />
public override void Write(byte[] buffer, int offset, int count)
=> throw new NotSupportedException();
/// <inheritdoc />
protected override void Dispose(bool disposing)
{
if (_disposed)
{
return;
}
try
{
if (disposing)
{
_stream.Dispose();
if (_job != null)
{
_transcodingJobHelper?.OnTranscodeEndRequest(_job);
}
}
}
finally
{
_disposed = true;
base.Dispose(disposing);
}
}
private void UpdateBytesWritten(int totalBytesRead)
{
if (_job != null)
{
_job.BytesDownloaded += totalBytesRead;
}
}
private bool KeepReading(long elapsed)
{
// If the job is null it's a live stream and will require user action to close, but don't keep it open indefinitely
return !_job?.HasExited ?? elapsed < _timeoutMs;
}
}
}