IllegalStateException in FrameDecoder

["이희승 (Trustin Lee)"]

I find a couple issues:

1) ChannelBuffer.bytesBefore() returns the number of bytes instead of an 
index.  Therefore, indexOfHeader should be renamed to 
'bytesBeforeHeader' or something similar, and 
buffer.readerIndex(indexOfHeader) should be replaced with 
buffer.skipBytes(bytesBeforeHeader)

2) After header is read and readerIndex advances, you check if there are 
enough bytes in the buffer for the message body, and just return when 
there are not enough bytes.  Because you advanced the readerIndex 
already for the header, the header will be lost next time decode() is 
called.

3) You don't need to call discardReadBytes().  I think this might 
confuse FrameDecoder.


On 05/26/2011 10:15 PM, Abraham Menacherry wrote:
> Trustin,
>
> Thanks for the detailed explanation. Could the following situation have
> caused it?
> 1) I read header bytes, advance the reader index and return.
> 2) I am expecting some body bytes of certain length.
> 3) I do buffer.readableBytes()>= expectedLen and find that it is not
> enough.
> 4) I return null.
> Note: Step 1 may not return if all the available bytes are there. Attaching
> the decoder file for reference.
>
> Thanks,
> Abraham.
> http://netty-forums-and-mailing-lists.685743.n2.nabble.com/file/n6406944/DeviceProtocolMultiplexer.java
> DeviceProtocolMultiplexer.java
>
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> View this message in context: http://netty-forums-and-mailing-lists.685743.n2.nabble.com/IllegalStateException-in-FrameDecoder-tp6406604p6406944.html
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-- 
Trustin Lee, http://gleamynode.net/