/// <summary>
/// Decodes the specified region of the buffer into an unadjusted frame length. The default implementation is
/// capable of decoding the specified region into an unsigned 8/16/24/32/64 bit integer. Override this method to
/// decode the length field encoded differently.
/// Note that this method must not modify the state of the specified buffer (e.g.
/// <see cref="IByteBuffer.ReaderIndex" />,
/// <see cref="IByteBuffer.WriterIndex" />, and the content of the buffer.)
/// </summary>
/// <param name="buffer">The buffer we'll be extracting the frame length from.</param>
/// <param name="offset">The offset from the absolute <see cref="IByteBuffer.ReaderIndex" />.</param>
/// <param name="length">The length of the framelenght field. Expected: 1, 2, 3, 4, or 8.</param>
/// <returns>A long integer that represents the unadjusted length of the next frame.</returns>
protected static long GetUnadjustedFrameLength(IByteBuffer buffer, int offset, int length)
{
return(length switch
{
1 => buffer.GetByte(offset),
2 => buffer.GetUnsignedShort(offset),
3 => buffer.GetUnsignedMedium(offset),
4 => buffer.GetInt(offset),
8 => buffer.GetLong(offset),
_ => CThrowHelper.ThrowDecoderException(length),
});
/// <inheritdoc />
public override void ChannelRead(IChannelHandlerContext context, object message)
{
if (message is IByteBuffer data)
{
ThreadLocalObjectList output = ThreadLocalObjectList.NewInstance();
try
{
_first = _cumulation is null;
_cumulation = _cumulator.Cumulate(context.Allocator, _first ? Unpooled.Empty : _cumulation, data);
CallDecode(context, _cumulation, output);
}
catch (DecoderException)
{
throw;
}
catch (Exception ex)
{
CThrowHelper.ThrowDecoderException(ex);
}
finally
{
try
{
if (_cumulation is object && !_cumulation.IsReadable())
{
_numReads = 0;
_ = _cumulation.Release();
_cumulation = null;
}
else if (++_numReads >= _discardAfterReads)
{
// We did enough reads already try to discard some bytes so we not risk to see a OOME.
// See https://github.com/netty/netty/issues/4275
_numReads = 0;
DiscardSomeReadBytes();
}
int size = output.Count;
_firedChannelRead |= (uint)size > 0u;
FireChannelRead(context, output, size);
}
finally
{
output.Return();
}
}
}
else
{
_ = context.FireChannelRead(message);
}
}
/// <inheritdoc />
public override void ChannelRead(IChannelHandlerContext context, object message)
{
ThreadLocalObjectList output = ThreadLocalObjectList.NewInstance();
try
{
if (this.AcceptInboundMessage(message))
{
var cast = (T)message;
try
{
this.Decode(context, cast, output);
}
finally
{
_ = ReferenceCountUtil.Release(cast);
}
}
else
{
output.Add(message);
}
}
catch (DecoderException)
{
throw;
}
catch (Exception e)
{
CThrowHelper.ThrowDecoderException(e);
}
finally
{
try
{
int size = output.Count;
for (int i = 0; i < size; i++)
{
_ = context.FireChannelRead(output[i]);
}
}
finally
{
output.Return();
}
}
}
/// <inheritdoc />
public override void ChannelRead(IChannelHandlerContext context, object message)
{
ThreadLocalObjectList output = ThreadLocalObjectList.NewInstance();
try
{
if (message is IByteBuffer byteBuffer)
{
try
{
var reader = new ByteBufferReader(byteBuffer);
Decode(context, ref reader, output);
}
finally
{
_ = ReferenceCountUtil.Release(message);
}
}
else
{
output.Add(message);
}
}
catch (DecoderException)
{
throw;
}
catch (Exception e)
{
CThrowHelper.ThrowDecoderException(e);
}
finally
{
try
{
int size = output.Count;
for (int i = 0; i < size; i++)
{
_ = context.FireChannelRead(output[i]);
}
}
finally
{
output.Return();
}
}
}
private void ChannelInputClosed(IChannelHandlerContext ctx, bool callChannelInactive)
{
ThreadLocalObjectList output = ThreadLocalObjectList.NewInstance();
try
{
ChannelInputClosed(ctx, output);
}
catch (DecoderException)
{
throw;
}
catch (Exception e)
{
CThrowHelper.ThrowDecoderException(e);
}
finally
{
try
{
if (_cumulation is object)
{
_ = _cumulation.Release();
_cumulation = null;
}
int size = output.Count;
if ((uint)size > 0u)
{
FireChannelRead(ctx, output, size);
// Something was read, call fireChannelReadComplete()
_ = ctx.FireChannelReadComplete();
}
if (callChannelInactive)
{
_ = ctx.FireChannelInactive();
}
}
finally
{
// Recycle in all cases
output.Return();
}
}
}
/// <summary>
/// Called once data should be decoded from the given <see cref="IByteBuffer"/>. This method will call
/// <see cref="Decode(IChannelHandlerContext, IByteBuffer, List{object})"/> as long as decoding should take place.
/// </summary>
/// <param name="context"></param>
/// <param name="input"></param>
/// <param name="output"></param>
protected virtual void CallDecode(IChannelHandlerContext context, IByteBuffer input, List <object> output)
{
if (context is null)
{
CThrowHelper.ThrowArgumentNullException(CExceptionArgument.context);
}
if (input is null)
{
CThrowHelper.ThrowArgumentNullException(CExceptionArgument.input);
}
if (output is null)
{
CThrowHelper.ThrowArgumentNullException(CExceptionArgument.output);
}
try
{
while (input.IsReadable())
{
int initialOutputCount = output.Count;
if ((uint)initialOutputCount > 0u)
{
FireChannelRead(context, output, initialOutputCount);
output.Clear();
// Check if this handler was removed before continuing with decoding.
// If it was removed, it is not safe to continue to operate on the buffer.
//
// See:
// - https://github.com/netty/netty/issues/4635
if (context.IsRemoved)
{
break;
}
initialOutputCount = 0;
}
int oldInputLength = input.ReadableBytes;
DecodeRemovalReentryProtection(context, input, output);
// Check if this handler was removed before continuing the loop.
// If it was removed, it is not safe to continue to operate on the buffer.
//
// See https://github.com/netty/netty/issues/1664
if (context.IsRemoved)
{
break;
}
bool noOutgoingMessages = 0u >= (uint)(oldInputLength - input.ReadableBytes);
if (0u >= (uint)(initialOutputCount - output.Count))
{
// no outgoing messages have been produced
if (noOutgoingMessages)
{
break;
}
else
{
continue;
}
}
if (noOutgoingMessages)
{
CThrowHelper.ThrowDecoderException_ByteToMessageDecoder(GetType());
}
if (SingleDecode)
{
break;
}
}
}
catch (DecoderException)
{
throw;
}
catch (Exception cause)
{
CThrowHelper.ThrowDecoderException(cause);
}
}