StreamFramer.cs

Go to the documentation of this file.

using System.Globalization;
using System.IO;
using System.Net.Security;
using System.Threading.Tasks;
 
namespace System.Net;
 
internal sealed class StreamFramer
{
    private readonly FrameHeader _writeHeader = new FrameHeader();
 
    private readonly FrameHeader _curReadHeader = new FrameHeader();
 
    private readonly byte[] _readHeaderBuffer = new byte[5];
 
    private readonly byte[] _writeHeaderBuffer = new byte[5];
 
    private bool _eof;
 
    public FrameHeader ReadHeader => _curReadHeader;
 
    public FrameHeader WriteHeader => _writeHeader;
 
    public async ValueTask<byte[]> ReadMessageAsync<TAdapter>(TAdapter adapter) where TAdapter : IReadWriteAdapter
    {
        if (_eof)
        {
            return null;
        }
        byte[] buffer = _readHeaderBuffer;
        int num;
        for (int offset = 0; offset < buffer.Length; offset += num)
        {
            num = await adapter.ReadAsync(buffer.AsMemory(offset)).ConfigureAwait(continueOnCapturedContext: false);
            if (num == 0)
            {
                if (offset == 0)
                {
                    _eof = true;
                    return null;
                }
                throw new IOException(System.SR.Format(System.SR.net_io_readfailure, System.SR.net_io_connectionclosed));
            }
        }
        _curReadHeader.CopyFrom(buffer, 0);
        if (_curReadHeader.PayloadSize > 65535)
        {
            throw new InvalidOperationException(System.SR.Format(System.SR.net_frame_size, 65535, _curReadHeader.PayloadSize.ToString(NumberFormatInfo.InvariantInfo)));
        }
        buffer = new byte[_curReadHeader.PayloadSize];
        for (int offset = 0; offset < buffer.Length; offset += num)
        {
            num = await adapter.ReadAsync(buffer.AsMemory(offset)).ConfigureAwait(continueOnCapturedContext: false);
            if (num == 0)
            {
                throw new IOException(System.SR.Format(System.SR.net_io_readfailure, System.SR.net_io_connectionclosed));
            }
        }
        return buffer;
    }
 
    public async Task WriteMessageAsync<TAdapter>(TAdapter adapter, byte[] message) where TAdapter : IReadWriteAdapter
    {
        if (message == null)
        {
            throw new ArgumentNullException("message");
        }
        _writeHeader.PayloadSize = message.Length;
        _writeHeader.CopyTo(_writeHeaderBuffer, 0);
        await adapter.WriteAsync(_writeHeaderBuffer, 0, _writeHeaderBuffer.Length).ConfigureAwait(continueOnCapturedContext: false);
        if (message.Length != 0)
        {
            await adapter.WriteAsync(message, 0, message.Length).ConfigureAwait(continueOnCapturedContext: false);
        }
    }
}