class/Npgsql/Npgsql/NpgsqlResourceManager.cs

   1 // NpgsqlResourceManager.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.Collections.Generic;
  27 using System.Transactions;
  28
  29 namespace Npgsql
  30 {
  31         internal interface INpgsqlResourceManager
  32         {
  33                 void Enlist(INpgsqlTransactionCallbacks transactionCallbacks, byte[] txToken);
  34                 byte[] Promote(INpgsqlTransactionCallbacks transactionCallbacks);
  35                 void CommitWork(string txName);
  36         void RollbackWork(string txName);
  37         }
  38
  39         internal class NpgsqlResourceManager : MarshalByRefObject, INpgsqlResourceManager
  40         {
  41         private readonly Dictionary<string, CommittableTransaction> _transactions = new Dictionary<string, CommittableTransaction>();
  42
  43         #region INpgsqlTransactionManager Members
  44
  45         public byte[] Promote(INpgsqlTransactionCallbacks callbacks)
  46         {
  47             CommittableTransaction tx = new CommittableTransaction();
  48             DurableResourceManager rm = new DurableResourceManager(this, callbacks, tx);
  49             byte[] token = TransactionInterop.GetTransmitterPropagationToken(tx);
  50             _transactions.Add(rm.TxName, tx);
  51             rm.Enlist(tx);
  52             return token;
  53         }
  54
  55         public void Enlist(INpgsqlTransactionCallbacks callbacks, byte[] txToken)
  56         {
  57             DurableResourceManager rm = new DurableResourceManager(this, callbacks);
  58             rm.Enlist(txToken);
  59         }
  60
  61         public void CommitWork(string txName)
  62         {
  63             CommittableTransaction tx;
  64             if (_transactions.TryGetValue(txName, out tx))
  65             {
  66                 tx.Commit();
  67                 _transactions.Remove(txName);
  68             }
  69         }
  70
  71         public void RollbackWork(string txName)
  72         {
  73             CommittableTransaction tx;
  74             if (_transactions.TryGetValue(txName, out tx))
  75             {
  76                 _transactions.Remove(txName);
  77                 // you can fail to commit,
  78                 // but you're not getting out
  79                 // of a rollback.  Remove from list first.
  80                 tx.Rollback();
  81             }
  82         }
  83
  84         #endregion
  85
  86                 private class DurableResourceManager : IEnlistmentNotification
  87                 {
  88                         private CommittableTransaction _tx;
  89                         private NpgsqlResourceManager _rm;
  90                         private readonly INpgsqlTransactionCallbacks _callbacks;
  91                         private string _txName;
  92
  93                         public DurableResourceManager(NpgsqlResourceManager rm, INpgsqlTransactionCallbacks callbacks)
  94                                 : this(rm, callbacks, null)
  95                         {
  96                         }
  97
  98                         public DurableResourceManager(NpgsqlResourceManager rm, INpgsqlTransactionCallbacks callbacks,
  99                                                       CommittableTransaction tx)
 100                         {
 101                                 _rm = rm;
 102                                 _tx = tx;
 103                                 _callbacks = callbacks;
 104                         }
 105
 106                         public string TxName
 107                         {
 108                                 get
 109                                 {
 110                                         // delay initialize since callback methods may be expensive
 111                                         if (_txName == null)
 112                                         {
 113                                                 _txName = _callbacks.GetName();
 114                                         }
 115                                         return _txName;
 116                                 }
 117                         }
 118
 119                         #region IEnlistmentNotification Members
 120
 121                         public void Commit(Enlistment enlistment)
 122                         {
 123                                 _callbacks.CommitTransaction();
 124                                 // TODO: remove record of prepared
 125                                 enlistment.Done();
 126                                 _callbacks.Dispose();
 127                         }
 128
 129                         public void InDoubt(Enlistment enlistment)
 130                         {
 131                                 // not going to happen when enlisted durably
 132                                 throw new NotImplementedException();
 133                         }
 134
 135                         public void Prepare(PreparingEnlistment preparingEnlistment)
 136                         {
 137                                 _callbacks.PrepareTransaction();
 138                                 // TODO: record prepared
 139                                 preparingEnlistment.Prepared();
 140                         }
 141
 142                         public void Rollback(Enlistment enlistment)
 143                         {
 144                                 _callbacks.RollbackTransaction();
 145                                 // TODO: remove record of prepared
 146                                 enlistment.Done();
 147                                 _callbacks.Dispose();
 148                         }
 149
 150                         #endregion
 151
 152                         private static readonly Guid rmGuid = new Guid("9e1b6d2d-8cdb-40ce-ac37-edfe5f880716");
 153
 154                         public Transaction Enlist(byte[] token)
 155                         {
 156                                 return Enlist(TransactionInterop.GetTransactionFromTransmitterPropagationToken(token));
 157                         }
 158
 159                         public Transaction Enlist(Transaction tx)
 160                         {
 161                                 tx.EnlistDurable(rmGuid, this, EnlistmentOptions.None);
 162                 return tx;
 163                         }
 164                 }
 165     }
 166 }