EmptyReadStream.cs

Go to the documentation of this file.

using System.IO;
using System.Threading;
using System.Threading.Tasks;
 
namespace System.Net.Http;
 
internal sealed class EmptyReadStream : HttpBaseStream
{
    internal static EmptyReadStream Instance { get; } = new EmptyReadStream();
 
 
    public override bool CanRead => true;
 
    public override bool CanWrite => false;
 
    private EmptyReadStream()
    {
    }
 
    protected override void Dispose(bool disposing)
    {
    }
 
    public override void Close()
    {
    }
 
    public override int Read(Span<byte> buffer)
    {
        return 0;
    }
 
    public override ValueTask<int> ReadAsync(Memory<byte> buffer, CancellationToken cancellationToken)
    {
        if (!cancellationToken.IsCancellationRequested)
        {
            return new ValueTask<int>(0);
        }
        return ValueTask.FromCanceled<int>(cancellationToken);
    }
 
    public override Task CopyToAsync(Stream destination, int bufferSize, CancellationToken cancellationToken)
    {
        Stream.ValidateCopyToArguments(destination, bufferSize);
        return HttpBaseStream.NopAsync(cancellationToken);
    }
 
    public override void Write(ReadOnlySpan<byte> buffer)
    {
        throw new NotSupportedException(System.SR.net_http_content_readonly_stream);
    }
 
    public override ValueTask WriteAsync(ReadOnlyMemory<byte> destination, CancellationToken cancellationToken)
    {
        throw new NotSupportedException();
    }
}