diff options
Diffstat (limited to 'dotnet/Qpid.Codec/CumulativeProtocolDecoder.cs')
| -rw-r--r-- | dotnet/Qpid.Codec/CumulativeProtocolDecoder.cs | 213 |
1 files changed, 113 insertions, 100 deletions
diff --git a/dotnet/Qpid.Codec/CumulativeProtocolDecoder.cs b/dotnet/Qpid.Codec/CumulativeProtocolDecoder.cs index 72c56e0b17..3d454b284b 100644 --- a/dotnet/Qpid.Codec/CumulativeProtocolDecoder.cs +++ b/dotnet/Qpid.Codec/CumulativeProtocolDecoder.cs @@ -19,121 +19,134 @@ * */ using System; +using log4net; using Qpid.Buffer; namespace Qpid.Codec { - public abstract class CumulativeProtocolDecoder : IProtocolDecoder - { - ByteBuffer _remaining; + public abstract class CumulativeProtocolDecoder : IProtocolDecoder + { + static ILog _logger = LogManager.GetLogger(typeof(CumulativeProtocolDecoder)); - /// <summary> - /// Creates a new instance with the 4096 bytes initial capacity of - /// cumulative buffer. - /// </summary> - protected CumulativeProtocolDecoder() - { - _remaining = ByteBuffer.Allocate(4096); - _remaining.IsAutoExpand = true; - } + ByteBuffer _remaining; - /// <summary> - /// Cumulates content of <tt>in</tt> into internal buffer and forwards - /// decoding request to {@link #doDecode(IoSession, ByteBuffer, ProtocolDecoderOutput)}. - /// <tt>doDecode()</tt> is invoked repeatedly until it returns <tt>false</tt> - /// and the cumulative buffer is compacted after decoding ends. - /// </summary> - /// <exception cref="Exception"> - /// if your <tt>doDecode()</tt> returned <tt>true</tt> not consuming the cumulative buffer. - /// </exception> - public void Decode(ByteBuffer input, IProtocolDecoderOutput output) - { - if (_remaining.Position != 0) // If there were remaining undecoded bytes - { - DecodeRemainingAndInput(input, output); - } - else - { - DecodeInput(input, output); - } - } + /// <summary> + /// Creates a new instance with the 4096 bytes initial capacity of + /// cumulative buffer. + /// </summary> + protected CumulativeProtocolDecoder() + { + _remaining = AllocateBuffer(); + } - private void DecodeInput(ByteBuffer input, IProtocolDecoderOutput output) - { - // Just decode the input buffer and remember any remaining undecoded bytes. - try - { - DecodeAll(input, output); - } - finally + /// <summary> + /// Cumulates content of <tt>in</tt> into internal buffer and forwards + /// decoding request to {@link #doDecode(IoSession, ByteBuffer, ProtocolDecoderOutput)}. + /// <tt>doDecode()</tt> is invoked repeatedly until it returns <tt>false</tt> + /// and the cumulative buffer is compacted after decoding ends. + /// </summary> + /// <exception cref="Exception"> + /// if your <tt>doDecode()</tt> returned <tt>true</tt> not consuming the cumulative buffer. + /// </exception> + public void Decode(ByteBuffer input, IProtocolDecoderOutput output) + { + if ( _remaining.Position != 0 ) // If there were remaining undecoded bytes + { + DecodeRemainingAndInput(input, output); + } else + { + DecodeInput(input, output); + } + } + + private void DecodeInput(ByteBuffer input, IProtocolDecoderOutput output) + { + _logger.Debug(string.Format("DecodeInput: input {0}", input.Remaining)); + // Just decode the input buffer and remember any remaining undecoded bytes. + try + { + DecodeAll(input, output); + } finally + { + if ( input.HasRemaining ) { - if (input.HasRemaining) - { - _remaining.Put(input); - } + _remaining.Put(input); } - } + } + } - private void DecodeRemainingAndInput(ByteBuffer input, IProtocolDecoderOutput output) - { - // Concatenate input buffer with left-over bytes. - _remaining.Put(input); - _remaining.Flip(); + private void DecodeRemainingAndInput(ByteBuffer input, IProtocolDecoderOutput output) + { + _logger.Debug(string.Format("DecodeRemainingAndInput: input {0}, remaining {1}", input.Remaining, _remaining.Position)); + // replace the _remainder buffer, so that we can leave the + // original one alone. Necessary because some consumer splice + // the buffer and only consume it until later, causing + // a race condition if we compact it too soon. + ByteBuffer newRemainding = AllocateBuffer(); + ByteBuffer temp = _remaining; + _remaining = newRemainding; + temp.Put(input); + temp.Flip(); + try + { + DecodeAll(temp, output); + } finally + { + if ( temp.Remaining > 0 ) + _remaining.Put(temp); + } + } - try - { - DecodeAll(_remaining, output); - } - finally + private void DecodeAll(ByteBuffer buf, IProtocolDecoderOutput output) + { + for ( ; ; ) + { + int oldPos = buf.Position; + bool decoded = DoDecode(buf, output); + if ( decoded ) { - _remaining.Compact(); - } - } + if ( buf.Position == oldPos ) + { + throw new Exception( + "doDecode() can't return true when buffer is not consumed."); + } - private void DecodeAll(ByteBuffer buf, IProtocolDecoderOutput output) - { - for (;;) + if ( !buf.HasRemaining ) + { + break; + } + } else { - int oldPos = buf.Position; - bool decoded = DoDecode(buf, output); - if (decoded) - { - if (buf.Position == oldPos) - { - throw new Exception( - "doDecode() can't return true when buffer is not consumed."); - } - - if (!buf.HasRemaining) - { - break; - } - } - else - { - break; - } + break; } - } + } + } + + /// <summary> + /// Implement this method to consume the specified cumulative buffer and + /// decode its content into message(s). + /// </summary> + /// <param name="input">the cumulative buffer</param> + /// <param name="output">decoder output</param> + /// <returns> + /// <tt>true</tt> if and only if there's more to decode in the buffer + /// and you want to have <tt>doDecode</tt> method invoked again. + /// Return <tt>false</tt> if remaining data is not enough to decode, + /// then this method will be invoked again when more data is cumulated. + /// </returns> + /// <exception cref="Exception">If cannot decode</exception> + protected abstract bool DoDecode(ByteBuffer input, IProtocolDecoderOutput output); - /// <summary> - /// Implement this method to consume the specified cumulative buffer and - /// decode its content into message(s). - /// </summary> - /// <param name="input">the cumulative buffer</param> - /// <param name="output">decoder output</param> - /// <returns> - /// <tt>true</tt> if and only if there's more to decode in the buffer - /// and you want to have <tt>doDecode</tt> method invoked again. - /// Return <tt>false</tt> if remaining data is not enough to decode, - /// then this method will be invoked again when more data is cumulated. - /// </returns> - /// <exception cref="Exception">If cannot decode</exception> - protected abstract bool DoDecode(ByteBuffer input, IProtocolDecoderOutput output); + public void Dispose() + { + _remaining = null; + } - public void Dispose() - { - _remaining = null; - } - } + private ByteBuffer AllocateBuffer() + { + ByteBuffer buffer = ByteBuffer.Allocate(4096); + buffer.IsAutoExpand = true; + return buffer; + } + } } |