class/Npgsql/Npgsql/NpgsqlPromotableSinglePhaseNotification.cs

   1 // NpgsqlPromotableSinglePhaseNotification.cs
   2 //
   3 // Author:
   4 //  Josh Cooley <jbnpgsql@tuxinthebox.net>
   5 //
   6 // Copyright (C) 2007, The Npgsql Development Team
   7 //
   8 // Permission to use, copy, modify, and distribute this software and its
   9 // documentation for any purpose, without fee, and without a written
  10 // agreement is hereby granted, provided that the above copyright notice
  11 // and this paragraph and the following two paragraphs appear in all copies.
  12 //
  13 // IN NO EVENT SHALL THE NPGSQL DEVELOPMENT TEAM BE LIABLE TO ANY PARTY
  14 // FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES,
  15 // INCLUDING LOST PROFITS, ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS
  16 // DOCUMENTATION, EVEN IF THE NPGSQL DEVELOPMENT TEAM HAS BEEN ADVISED OF
  17 // THE POSSIBILITY OF SUCH DAMAGE.
  18 //
  19 // THE NPGSQL DEVELOPMENT TEAM SPECIFICALLY DISCLAIMS ANY WARRANTIES,
  20 // INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
  21 // AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
  22 // ON AN "AS IS" BASIS, AND THE NPGSQL DEVELOPMENT TEAM HAS NO OBLIGATIONS
  23 // TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
  24
  25 using System;
  26 using System.Transactions;
  27
  28 namespace Npgsql
  29 {
  30         internal class NpgsqlPromotableSinglePhaseNotification : IPromotableSinglePhaseNotification
  31         {
  32                 private readonly NpgsqlConnection _connection;
  33                 private IsolationLevel _isolationLevel;
  34                 private NpgsqlTransaction _npgsqlTx;
  35                 private NpgsqlTransactionCallbacks _callbacks;
  36         private INpgsqlResourceManager _rm;
  37         private bool _inTransaction;
  38
  39                 private static readonly String CLASSNAME = "NpgsqlPromotableSinglePhaseNotification";
  40
  41                 public NpgsqlPromotableSinglePhaseNotification(NpgsqlConnection connection)
  42                 {
  43                         _connection = connection;
  44                 }
  45
  46                 public void Enlist(Transaction tx)
  47                 {
  48                         NpgsqlEventLog.LogMethodEnter(LogLevel.Debug, CLASSNAME, "Enlist");
  49                         if (tx != null)
  50                         {
  51                                 _isolationLevel = tx.IsolationLevel;
  52                                 if (!tx.EnlistPromotableSinglePhase(this))
  53                                 {
  54                                         // must already have a durable resource
  55                                         // start transaction
  56                                         _npgsqlTx = _connection.BeginTransaction(ConvertIsolationLevel(_isolationLevel));
  57                     _inTransaction = true;
  58                     _rm = CreateResourceManager();
  59                     _callbacks = new NpgsqlTransactionCallbacks(_connection);
  60                     _rm.Enlist(_callbacks, TransactionInterop.GetTransmitterPropagationToken(tx));
  61                                         // enlisted in distributed transaction
  62                                         // disconnect and cleanup local transaction
  63                                         _npgsqlTx.Cancel();
  64                                         _npgsqlTx.Dispose();
  65                                         _npgsqlTx = null;
  66                                 }
  67                         }
  68                 }
  69
  70                 /// <summary>
  71                 /// Used when a connection is closed
  72                 /// </summary>
  73                 public void Prepare()
  74                 {
  75             NpgsqlEventLog.LogMethodEnter(LogLevel.Debug, CLASSNAME, "Prepare");
  76             if (_inTransaction)
  77             {
  78                 // may not be null if Promote or Enlist is called first
  79                 if (_callbacks == null)
  80                 {
  81                     _callbacks = new NpgsqlTransactionCallbacks(_connection);
  82                 }
  83                 _callbacks.PrepareTransaction();
  84                 if (_npgsqlTx != null)
  85                 {
  86                     // cancel the NpgsqlTransaction since this will
  87                     // be handled by a two phase commit.
  88                     _npgsqlTx.Cancel();
  89                     _npgsqlTx.Dispose();
  90                     _npgsqlTx = null;
  91                 }
  92             }
  93                 }
  94
  95                 #region IPromotableSinglePhaseNotification Members
  96
  97                 public void Initialize()
  98                 {
  99                         NpgsqlEventLog.LogMethodEnter(LogLevel.Debug, CLASSNAME, "Initialize");
 100                         _npgsqlTx = _connection.BeginTransaction(ConvertIsolationLevel(_isolationLevel));
 101             _inTransaction = true;
 102                 }
 103
 104                 public void Rollback(SinglePhaseEnlistment singlePhaseEnlistment)
 105                 {
 106                         NpgsqlEventLog.LogMethodEnter(LogLevel.Debug, CLASSNAME, "Rollback");
 107             // try to rollback the transaction with either the
 108             // ADO.NET transaction or the callbacks that managed the
 109             // two phase commit transaction.
 110                         if (_npgsqlTx != null)
 111                         {
 112                                 _npgsqlTx.Rollback();
 113                                 _npgsqlTx.Dispose();
 114                 _npgsqlTx = null;
 115                 singlePhaseEnlistment.Aborted();
 116                         }
 117             else if (_callbacks != null)
 118             {
 119                 if (_rm != null)
 120                 {
 121                     _rm.RollbackWork(_callbacks.GetName());
 122                     singlePhaseEnlistment.Aborted();
 123                 }
 124                 else
 125                 {
 126                     _callbacks.RollbackTransaction();
 127                     singlePhaseEnlistment.Aborted();
 128                 }
 129                 _callbacks = null;
 130             }
 131             _inTransaction = false;
 132                 }
 133
 134                 public void SinglePhaseCommit(SinglePhaseEnlistment singlePhaseEnlistment)
 135                 {
 136                         NpgsqlEventLog.LogMethodEnter(LogLevel.Debug, CLASSNAME, "SinglePhaseCommit");
 137                         if (_npgsqlTx != null)
 138                         {
 139                                 _npgsqlTx.Commit();
 140                                 _npgsqlTx.Dispose();
 141                                 _npgsqlTx = null;
 142                                 singlePhaseEnlistment.Committed();
 143                         }
 144                         else if (_callbacks != null)
 145                         {
 146                 if (_rm != null)
 147                 {
 148                     _rm.CommitWork(_callbacks.GetName());
 149                     singlePhaseEnlistment.Committed();
 150                 }
 151                 else
 152                 {
 153                     _callbacks.CommitTransaction();
 154                     singlePhaseEnlistment.Committed();
 155                 }
 156                 _callbacks = null;
 157                         }
 158             _inTransaction = false;
 159                 }
 160
 161                 #endregion
 162
 163                 #region ITransactionPromoter Members
 164
 165                 public byte[] Promote()
 166                 {
 167                         NpgsqlEventLog.LogMethodEnter(LogLevel.Debug, CLASSNAME, "Promote");
 168             _rm = CreateResourceManager();
 169             // may not be null if Prepare or Enlist is called first
 170             if (_callbacks == null)
 171             {
 172                 _callbacks = new NpgsqlTransactionCallbacks(_connection);
 173             }
 174             byte[] token = _rm.Promote(_callbacks);
 175             // mostly likely case for this is the transaction has been prepared.
 176             if (_npgsqlTx != null)
 177             {
 178                 // cancel the NpgsqlTransaction since this will
 179                 // be handled by a two phase commit.
 180                 _npgsqlTx.Cancel();
 181                 _npgsqlTx.Dispose();
 182                 _npgsqlTx = null;
 183             }
 184                         return token;
 185                 }
 186
 187                 #endregion
 188
 189                 private static INpgsqlResourceManager _resourceManager;
 190
 191                 private static INpgsqlResourceManager CreateResourceManager()
 192                 {
 193                         // TODO: create network proxy for resource manager
 194                         if (_resourceManager == null)
 195                         {
 196                                 AppDomain rmDomain = AppDomain.CreateDomain("NpgsqlResourceManager", AppDomain.CurrentDomain.Evidence, AppDomain.CurrentDomain.SetupInformation);
 197                                 _resourceManager =
 198                                         (INpgsqlResourceManager)
 199                                         rmDomain.CreateInstanceAndUnwrap(typeof (NpgsqlResourceManager).Assembly.FullName,
 200                                                                          typeof (NpgsqlResourceManager).FullName);
 201                         }
 202                         return _resourceManager;
 203                         //return new NpgsqlResourceManager();
 204                 }
 205
 206                 private static System.Data.IsolationLevel ConvertIsolationLevel(IsolationLevel _isolationLevel)
 207                 {
 208                         switch (_isolationLevel)
 209                         {
 210                                 case IsolationLevel.Chaos:
 211                                         return System.Data.IsolationLevel.Chaos;
 212                                 case IsolationLevel.ReadCommitted:
 213                                         return System.Data.IsolationLevel.ReadCommitted;
 214                                 case IsolationLevel.ReadUncommitted:
 215                                         return System.Data.IsolationLevel.ReadUncommitted;
 216                                 case IsolationLevel.RepeatableRead:
 217                                         return System.Data.IsolationLevel.RepeatableRead;
 218                                 case IsolationLevel.Serializable:
 219                                         return System.Data.IsolationLevel.Serializable;
 220                                 case IsolationLevel.Snapshot:
 221                                         return System.Data.IsolationLevel.Snapshot;
 222                                 case IsolationLevel.Unspecified:
 223                                 default:
 224                                         return System.Data.IsolationLevel.Unspecified;
 225                         }
 226                 }
 227         }
 228 }