jellyfin/MediaBrowser.Api/LiveTv/ProgressiveFileCopier.cs
2017-10-14 02:52:56 -04:00

162 lines
5.6 KiB
C#

using System;
using System.Collections.Generic;
using System.IO;
using System.Threading;
using System.Threading.Tasks;
using MediaBrowser.Controller.Library;
using MediaBrowser.Model.IO;
using MediaBrowser.Model.Logging;
using MediaBrowser.Model.Services;
using MediaBrowser.Model.System;
namespace MediaBrowser.Api.LiveTv
{
public class ProgressiveFileCopier : IAsyncStreamWriter, IHasHeaders
{
private readonly IFileSystem _fileSystem;
private readonly ILogger _logger;
private readonly string _path;
private readonly Dictionary<string, string> _outputHeaders;
const int StreamCopyToBufferSize = 81920;
private long _bytesWritten = 0;
public long StartPosition { get; set; }
public bool AllowEndOfFile = true;
private readonly IDirectStreamProvider _directStreamProvider;
private readonly IEnvironmentInfo _environment;
public ProgressiveFileCopier(IFileSystem fileSystem, string path, Dictionary<string, string> outputHeaders, ILogger logger, IEnvironmentInfo environment)
{
_fileSystem = fileSystem;
_path = path;
_outputHeaders = outputHeaders;
_logger = logger;
_environment = environment;
}
public ProgressiveFileCopier(IDirectStreamProvider directStreamProvider, Dictionary<string, string> outputHeaders, ILogger logger, IEnvironmentInfo environment)
{
_directStreamProvider = directStreamProvider;
_outputHeaders = outputHeaders;
_logger = logger;
_environment = environment;
}
public IDictionary<string, string> Headers
{
get
{
return _outputHeaders;
}
}
private Stream GetInputStream(bool allowAsyncFileRead)
{
var fileOpenOptions = FileOpenOptions.SequentialScan;
if (allowAsyncFileRead)
{
fileOpenOptions |= FileOpenOptions.Asynchronous;
}
return _fileSystem.GetFileStream(_path, FileOpenMode.Open, FileAccessMode.Read, FileShareMode.ReadWrite, fileOpenOptions);
}
public async Task WriteToAsync(Stream outputStream, CancellationToken cancellationToken)
{
if (_directStreamProvider != null)
{
await _directStreamProvider.CopyToAsync(outputStream, cancellationToken).ConfigureAwait(false);
return;
}
var eofCount = 0;
// use non-async filestream along with read due to https://github.com/dotnet/corefx/issues/6039
var allowAsyncFileRead = _environment.OperatingSystem != MediaBrowser.Model.System.OperatingSystem.Windows;
using (var inputStream = GetInputStream(allowAsyncFileRead))
{
if (StartPosition > 0)
{
inputStream.Position = StartPosition;
}
var emptyReadLimit = AllowEndOfFile ? 20 : 100;
while (eofCount < emptyReadLimit)
{
int bytesRead;
if (allowAsyncFileRead)
{
bytesRead = await CopyToInternalAsync(inputStream, outputStream, cancellationToken).ConfigureAwait(false);
}
else
{
bytesRead = await CopyToInternalAsyncWithSyncRead(inputStream, outputStream, cancellationToken).ConfigureAwait(false);
}
//var position = fs.Position;
//_logger.Debug("Streamed {0} bytes to position {1} from file {2}", bytesRead, position, path);
if (bytesRead == 0)
{
eofCount++;
await Task.Delay(100, cancellationToken).ConfigureAwait(false);
}
else
{
eofCount = 0;
}
}
}
}
private async Task<int> CopyToInternalAsyncWithSyncRead(Stream source, Stream destination, CancellationToken cancellationToken)
{
var array = new byte[StreamCopyToBufferSize];
int bytesRead;
int totalBytesRead = 0;
while ((bytesRead = source.Read(array, 0, array.Length)) != 0)
{
var bytesToWrite = bytesRead;
if (bytesToWrite > 0)
{
await destination.WriteAsync(array, 0, Convert.ToInt32(bytesToWrite), cancellationToken).ConfigureAwait(false);
_bytesWritten += bytesRead;
totalBytesRead += bytesRead;
}
}
return totalBytesRead;
}
private async Task<int> CopyToInternalAsync(Stream source, Stream destination, CancellationToken cancellationToken)
{
var array = new byte[StreamCopyToBufferSize];
int bytesRead;
int totalBytesRead = 0;
while ((bytesRead = await source.ReadAsync(array, 0, array.Length, cancellationToken).ConfigureAwait(false)) != 0)
{
var bytesToWrite = bytesRead;
if (bytesToWrite > 0)
{
await destination.WriteAsync(array, 0, Convert.ToInt32(bytesToWrite), cancellationToken).ConfigureAwait(false);
_bytesWritten += bytesRead;
totalBytesRead += bytesRead;
}
}
return totalBytesRead;
}
}
}