IFileStreamProvider that provides a ISeekableFileStreamProvider from an input Stream. More...

Inheritance diagram for Tgstation.Server.Host.IO.BufferedFileStreamProvider:

[legend]

Collaboration diagram for Tgstation.Server.Host.IO.BufferedFileStreamProvider:

[legend]

Public Member Functions

BufferedFileStreamProvider (Stream input)

Initializes a new instance of the BufferedFileStreamProvider class.

async ValueTask DisposeAsync ()

async ValueTask< Stream > GetResult (CancellationToken cancellationToken)

Gets the provided Stream. May be called multiple times, though cancelling any may cause all calls to be cancelled. All calls yield the same Stream reference.

Parameters

cancellationToken The CancellationToken for the operation.

Returns: A ValueTask<TResult> resulting in the provided Stream.

The resulting Stream is owned by the IFileStreamProvider and is short lived unless otherwise specified. It should be buffered if it needs use outside the lifetime of the IFileStreamProvider.

async ValueTask< MemoryStream > GetOwnedResult (CancellationToken cancellationToken)

Gets the provided MemoryStream. May be called multiple times, though cancelling any may cause all calls to be cancelled.

Parameters

cancellationToken The CancellationToken for the operation.

Returns: A ValueTask<TResult> resulting in the provided MemoryStream on success.

Task EnsureBuffered (CancellationToken cancellationToken)

Ensures the input Stream has been copied to the buffer.

Properties
bool	Disposed `[get]`
	If the ISeekableFileStreamProvider has had global::System.IAsyncDisposable.DisposeAsync called on it.

Properties inherited from Tgstation.Server.Host.IO.ISeekableFileStreamProvider

Private Member Functions
async ValueTask<(MemoryStream Stream, long StreamLength)>	GetResultInternal (CancellationToken cancellationToken)
	Gets the shared MemoryStream and its Stream.Length.

Private Attributes
readonly Stream	input
	The original input Stream must remain valid for the lifetime of the BufferedFileStreamProvider or until GetResult(CancellationToken) first returns.

readonly SemaphoreSlim	semaphore
	The SemaphoreSlim used to synchronize writes to buffer.

volatile? MemoryStream	buffer
	The backing Stream.

volatile bool	buffered
	If buffer has been populated.

Detailed Description

IFileStreamProvider that provides a ISeekableFileStreamProvider from an input Stream.

Definition at line 13 of file BufferedFileStreamProvider.cs.

Constructor & Destructor Documentation

◆ BufferedFileStreamProvider()

Tgstation.Server.Host.IO.BufferedFileStreamProvider.BufferedFileStreamProvider ( Stream input )

Initializes a new instance of the BufferedFileStreamProvider class.

Parameters

input The value of input.

Definition at line 42 of file BufferedFileStreamProvider.cs.

        {
            this.input = input ?? throw new ArgumentNullException(nameof(input));
 
            semaphore = new SemaphoreSlim(1);
            try
            {
                buffer = new MemoryStream();
            }
            catch
            {
                semaphore.Dispose();
                throw;
            }
        }

References Tgstation.Server.Host.IO.BufferedFileStreamProvider.buffer, Tgstation.Server.Host.IO.BufferedFileStreamProvider.input, and Tgstation.Server.Host.IO.BufferedFileStreamProvider.semaphore.

Member Function Documentation

◆ DisposeAsync()

async ValueTask Tgstation.Server.Host.IO.BufferedFileStreamProvider.DisposeAsync ( )

Definition at line 59 of file BufferedFileStreamProvider.cs.

        {
            MemoryStream? localBuffer;
            lock (semaphore)
            {
                localBuffer = buffer;
                if (localBuffer == null)
                    return;
 
                // important to drop the reference so it can properly GC
                // The implementation of MemoryStream doesn't fucking do this for some reason
                buffer = null;
                buffered = true;
            }
 
            var bufferDispose = localBuffer.DisposeAsync();
            semaphore.Dispose();
            await bufferDispose;
        }

References Tgstation.Server.Host.IO.BufferedFileStreamProvider.buffer, Tgstation.Server.Host.IO.BufferedFileStreamProvider.buffered, and Tgstation.Server.Host.IO.BufferedFileStreamProvider.semaphore.

◆ EnsureBuffered()

Task Tgstation.Server.Host.IO.BufferedFileStreamProvider.EnsureBuffered ( CancellationToken cancellationToken )

Ensures the input Stream has been copied to the buffer.

Parameters

cancellationToken The CancellationToken for the operation.

Returns: A Task representing the running operation.

◆ GetOwnedResult()

async ValueTask< MemoryStream > Tgstation.Server.Host.IO.BufferedFileStreamProvider.GetOwnedResult ( CancellationToken cancellationToken )

Gets the provided MemoryStream. May be called multiple times, though cancelling any may cause all calls to be cancelled.

Parameters

cancellationToken The CancellationToken for the operation.

Returns: A ValueTask<TResult> resulting in the provided MemoryStream on success.

Implements Tgstation.Server.Host.IO.ISeekableFileStreamProvider.

Definition at line 87 of file BufferedFileStreamProvider.cs.

        {
            var (sharedStream, length) = await GetResultInternal(cancellationToken);
            return new MemoryStream(sharedStream.GetBuffer(), 0, (int)length, false, true);
        }

References Tgstation.Server.Host.IO.BufferedFileStreamProvider.GetResultInternal().

Here is the call graph for this function:

◆ GetResult()

async ValueTask< Stream > Tgstation.Server.Host.IO.BufferedFileStreamProvider.GetResult ( CancellationToken cancellationToken )

Gets the provided Stream. May be called multiple times, though cancelling any may cause all calls to be cancelled. All calls yield the same Stream reference.

Parameters

cancellationToken The CancellationToken for the operation.

Returns: A ValueTask<TResult> resulting in the provided Stream.

The resulting Stream is owned by the IFileStreamProvider and is short lived unless otherwise specified. It should be buffered if it needs use outside the lifetime of the IFileStreamProvider.

Implements Tgstation.Server.Host.IO.IFileStreamProvider.

Definition at line 80 of file BufferedFileStreamProvider.cs.

        {
            var (sharedStream, _) = await GetResultInternal(cancellationToken);
            return sharedStream;
        }

References Tgstation.Server.Host.IO.BufferedFileStreamProvider.GetResultInternal().

Here is the call graph for this function:

◆ GetResultInternal()

async ValueTask<(MemoryStream Stream, long StreamLength)> Tgstation.Server.Host.IO.BufferedFileStreamProvider.GetResultInternal ( CancellationToken cancellationToken )

private

Gets the shared MemoryStream and its Stream.Length.

Parameters

cancellationToken The CancellationToken for the operation.

Returns: A Task<TResult> resulting in buffer and its Stream.Length.

Definition at line 105 of file BufferedFileStreamProvider.cs.

        {
            if (!buffered)
                using (await SemaphoreSlimContext.Lock(semaphore, cancellationToken))
                    if (!buffered)
                    {
                        MemoryStream localBuffer;
                        lock (semaphore)
                            localBuffer = buffer ?? throw new ObjectDisposedException(nameof(BufferedFileStreamProvider));
 
                        await input.CopyToAsync(localBuffer, cancellationToken);
                        localBuffer.Seek(0, SeekOrigin.Begin);
                        buffered = true;
                        return (Stream: localBuffer, StreamLength: localBuffer.Length);
                    }
 
            lock (semaphore)
            {
                var localBuffer = buffer ?? throw new ObjectDisposedException(nameof(BufferedFileStreamProvider));
                return (
                    Stream: localBuffer,
                    StreamLength: localBuffer.Length);
            }
        }