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/*
*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*
*/
using System;
using System.Collections;
using log4net;
using Apache.Qpid.Buffer;
using Apache.Qpid.Codec;
using Apache.Qpid.Codec.Demux;
namespace Apache.Qpid.Framing
{
public class AMQDataBlockDecoder : IMessageDecoder
{
private static ILog _logger = LogManager.GetLogger(typeof(AMQDataBlockDecoder));
private Hashtable _supportedBodies = new Hashtable();
private bool _disabled = false;
public AMQDataBlockDecoder()
{
_supportedBodies[AMQMethodBody.TYPE] = AMQMethodBodyFactory.GetInstance();
_supportedBodies[ContentHeaderBody.TYPE] = ContentHeaderBodyFactory.GetInstance();
_supportedBodies[ContentBody.TYPE] = ContentBodyFactory.GetInstance();
_supportedBodies[HeartbeatBody.TYPE] = new HeartbeatBodyFactory();
}
public MessageDecoderResult Decodable(ByteBuffer input)
{
if (_disabled)
{
return MessageDecoderResult.NOT_OK;
}
// final +1 represents the command end which we know we must require even
// if there is an empty body
if (input.Remaining < 1)
{
return MessageDecoderResult.NEED_DATA;
}
byte type = input.GetByte();
// we have to check this isn't a protocol initiation frame here - we can't tell later on and we end up
// waiting for more data. This could be improved if MINA supported some kind of state awareness when decoding
if ((char)type == 'A')
{
_logger.Error("Received what appears to be a protocol initiation frame");
return MessageDecoderResult.NOT_OK;
}
// zero, channel, body size and end byte
if (input.Remaining < (1 + 2 + 4 + 1))
{
return MessageDecoderResult.NEED_DATA;
}
int channel = input.GetUInt16();
long bodySize = input.GetUInt32();
// bodySize can be zero
if (type <= 0 || channel < 0 || bodySize < 0)
{
_logger.Error(String.Format("Error decoding frame: Type={0}, Channel={1}, BodySize={2}", type, channel, bodySize));
return MessageDecoderResult.NOT_OK;
}
if (input.Remaining < (bodySize + 1))
{
return MessageDecoderResult.NEED_DATA;
}
if (IsSupportedFrameType(type))
{
if (_logger.IsDebugEnabled)
{
// we have read 7 bytes so far, so output 7 + bodysize + 1 (for end byte) to get complete data block size
// this logging statement is useful when looking at exactly what size of data is coming in/out
// the broker
_logger.Debug("Able to decode data block of size " + (bodySize + 8));
}
return MessageDecoderResult.OK;
}
else
{
return MessageDecoderResult.NOT_OK;
}
}
private bool IsSupportedFrameType(byte frameType)
{
bool result = _supportedBodies.ContainsKey(frameType);
if (!result)
{
_logger.Warn("AMQDataBlockDecoder does not handle frame type " + frameType);
}
return result;
}
protected Object CreateAndPopulateFrame(ByteBuffer input)
{
byte type = input.GetByte();
ushort channel = input.GetUInt16();
uint bodySize = input.GetUInt32();
IBodyFactory bodyFactory = (IBodyFactory)_supportedBodies[type];
if (bodyFactory == null)
{
throw new AMQFrameDecodingException("Unsupported body type: " + type);
}
AMQFrame frame = new AMQFrame();
frame.PopulateFromBuffer(input, channel, bodySize, bodyFactory);
byte marker = input.GetByte();
if (marker != 0xCE) {
throw new FormatException("marker is not 0xCE");
}
return frame;
}
public MessageDecoderResult Decode(ByteBuffer input, IProtocolDecoderOutput output)
{
output.Write(CreateAndPopulateFrame(input));
return MessageDecoderResult.OK;
}
public bool Disabled
{
set
{
_disabled = value;
}
}
}
}
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