mcs/class/RabbitMQ.Client/src/client/impl/CommandAssembler.cs

   1 // This source code is dual-licensed under the Apache License, version
   2 // 2.0, and the Mozilla Public License, version 1.1.
   3 //
   4 // The APL v2.0:
   5 //
   6 //---------------------------------------------------------------------------
   7 //   Copyright (C) 2007-2010 LShift Ltd., Cohesive Financial
   8 //   Technologies LLC., and Rabbit Technologies Ltd.
   9 //
  10 //   Licensed under the Apache License, Version 2.0 (the "License");
  11 //   you may not use this file except in compliance with the License.
  12 //   You may obtain a copy of the License at
  13 //
  14 //       http://www.apache.org/licenses/LICENSE-2.0
  15 //
  16 //   Unless required by applicable law or agreed to in writing, software
  17 //   distributed under the License is distributed on an "AS IS" BASIS,
  18 //   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  19 //   See the License for the specific language governing permissions and
  20 //   limitations under the License.
  21 //---------------------------------------------------------------------------
  22 //
  23 // The MPL v1.1:
  24 //
  25 //---------------------------------------------------------------------------
  26 //   The contents of this file are subject to the Mozilla Public License
  27 //   Version 1.1 (the "License"); you may not use this file except in
  28 //   compliance with the License. You may obtain a copy of the License at
  29 //   http://www.rabbitmq.com/mpl.html
  30 //
  31 //   Software distributed under the License is distributed on an "AS IS"
  32 //   basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See the
  33 //   License for the specific language governing rights and limitations
  34 //   under the License.
  35 //
  36 //   The Original Code is The RabbitMQ .NET Client.
  37 //
  38 //   The Initial Developers of the Original Code are LShift Ltd,
  39 //   Cohesive Financial Technologies LLC, and Rabbit Technologies Ltd.
  40 //
  41 //   Portions created before 22-Nov-2008 00:00:00 GMT by LShift Ltd,
  42 //   Cohesive Financial Technologies LLC, or Rabbit Technologies Ltd
  43 //   are Copyright (C) 2007-2008 LShift Ltd, Cohesive Financial
  44 //   Technologies LLC, and Rabbit Technologies Ltd.
  45 //
  46 //   Portions created by LShift Ltd are Copyright (C) 2007-2010 LShift
  47 //   Ltd. Portions created by Cohesive Financial Technologies LLC are
  48 //   Copyright (C) 2007-2010 Cohesive Financial Technologies
  49 //   LLC. Portions created by Rabbit Technologies Ltd are Copyright
  50 //   (C) 2007-2010 Rabbit Technologies Ltd.
  51 //
  52 //   All Rights Reserved.
  53 //
  54 //   Contributor(s): ______________________________________.
  55 //
  56 //---------------------------------------------------------------------------
  57 using System;
  58 using System.IO;
  59 using System.Collections;
  60
  61 using RabbitMQ.Util;
  62
  63 // We use spec version 0-9 for common constants such as frame types
  64 // and the frame end byte, since they don't vary *within the versions
  65 // we support*. Obviously we may need to revisit this if that ever
  66 // changes.
  67 using CommonFraming = RabbitMQ.Client.Framing.v0_9;
  68 using System.Diagnostics;
  69
  70 namespace RabbitMQ.Client.Impl
  71 {
  72     public enum AssemblyState
  73     {
  74         ExpectingMethod,
  75         ExpectingContentHeader,
  76         ExpectingContentBody,
  77         Complete
  78     }
  79
  80     public class CommandAssembler
  81     {
  82         public AbstractProtocolBase m_protocol;
  83         public AssemblyState m_state;
  84         public Command m_command;
  85         public ulong m_remainingBodyBytes;
  86
  87         public CommandAssembler(AbstractProtocolBase protocol)
  88         {
  89             m_protocol = protocol;
  90             Reset();
  91         }
  92
  93         private void Reset()
  94         {
  95             m_state = AssemblyState.ExpectingMethod;
  96             m_command = new Command();
  97             m_remainingBodyBytes = 0;
  98         }
  99
 100         private Command CompletedCommand()
 101         {
 102             if (m_state == AssemblyState.Complete)
 103             {
 104                 Command result = m_command;
 105                 Reset();
 106                 return result;
 107             }
 108             else
 109             {
 110                 return null;
 111             }
 112         }
 113
 114         private void UpdateContentBodyState()
 115         {
 116             m_state = (m_remainingBodyBytes > 0)
 117                 ? AssemblyState.ExpectingContentBody
 118                 : AssemblyState.Complete;
 119         }
 120
 121         public Command HandleFrame(Frame f)
 122         {
 123             switch (m_state)
 124             {
 125                 case AssemblyState.ExpectingMethod:
 126                     {
 127                         if (f.Type != CommonFraming.Constants.FrameMethod)
 128                         {
 129                             throw new UnexpectedFrameException(f);
 130                         }
 131                         m_command.m_method = m_protocol.DecodeMethodFrom(f.GetReader());
 132                         m_state = m_command.m_method.HasContent
 133                             ? AssemblyState.ExpectingContentHeader
 134                             : AssemblyState.Complete;
 135                         return CompletedCommand();
 136                     }
 137                 case AssemblyState.ExpectingContentHeader:
 138                     {
 139                         if (f.Type != CommonFraming.Constants.FrameHeader)
 140                         {
 141                             throw new UnexpectedFrameException(f);
 142                         }
 143                         NetworkBinaryReader reader = f.GetReader();
 144                         m_command.m_header = m_protocol.DecodeContentHeaderFrom(reader);
 145                         m_remainingBodyBytes = m_command.m_header.ReadFrom(reader);
 146                         UpdateContentBodyState();
 147                         return CompletedCommand();
 148                     }
 149                 case AssemblyState.ExpectingContentBody:
 150                     {
 151                         if (f.Type != CommonFraming.Constants.FrameBody)
 152                         {
 153                             throw new UnexpectedFrameException(f);
 154                         }
 155                         byte[] fragment = f.Payload;
 156                         m_command.AppendBodyFragment(fragment);
 157                         if ((ulong)fragment.Length > m_remainingBodyBytes)
 158                         {
 159                             throw new MalformedFrameException
 160                                 (string.Format("Overlong content body received - {0} bytes remaining, {1} bytes received",
 161                                                m_remainingBodyBytes,
 162                                                fragment.Length));
 163                         }
 164                         m_remainingBodyBytes -= (ulong)fragment.Length;
 165                         UpdateContentBodyState();
 166                         return CompletedCommand();
 167                     }
 168                 case AssemblyState.Complete:
 169                 default:
 170                     Trace.Fail(string.Format(
 171                         "Received frame in invalid state {0}; {1}",
 172                         m_state,
 173                         f));
 174                     return null;
 175             }
 176         }
 177     }
 178 }