code.grnet.gr Git - pithos-ms-client/blob - trunk/Pithos.Core/Agents/SnapshotDifferencer.cs

   1 #region\r
   2 /* -----------------------------------------------------------------------\r
   3  * <copyright file="SnapshotDifferencer.cs" company="GRNet">\r
   4  * \r
   5  * Copyright 2011-2012 GRNET S.A. All rights reserved.\r
   6  *\r
   7  * Redistribution and use in source and binary forms, with or\r
   8  * without modification, are permitted provided that the following\r
   9  * conditions are met:\r
  10  *\r
  11  *   1. Redistributions of source code must retain the above\r
  12  *      copyright notice, this list of conditions and the following\r
  13  *      disclaimer.\r
  14  *\r
  15  *   2. Redistributions in binary form must reproduce the above\r
  16  *      copyright notice, this list of conditions and the following\r
  17  *      disclaimer in the documentation and/or other materials\r
  18  *      provided with the distribution.\r
  19  *\r
  20  *\r
  21  * THIS SOFTWARE IS PROVIDED BY GRNET S.A. ``AS IS'' AND ANY EXPRESS\r
  22  * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED\r
  23  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR\r
  24  * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL GRNET S.A OR\r
  25  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,\r
  26  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT\r
  27  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF\r
  28  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED\r
  29  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT\r
  30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN\r
  31  * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE\r
  32  * POSSIBILITY OF SUCH DAMAGE.\r
  33  *\r
  34  * The views and conclusions contained in the software and\r
  35  * documentation are those of the authors and should not be\r
  36  * interpreted as representing official policies, either expressed\r
  37  * or implied, of GRNET S.A.\r
  38  * </copyright>\r
  39  * -----------------------------------------------------------------------\r
  40  */\r
  41 #endregion\r
  42 using System.Collections.Concurrent;\r
  43 using Pithos.Interfaces;\r
  44 using Pithos.Network;\r
  45 \r
  46 namespace Pithos.Core.Agents\r
  47 {\r
  48     using System;\r
  49     using System.Collections.Generic;\r
  50     using System.Linq;\r
  51     using System.Text;\r
  52 \r
  53     /// <summary>\r
  54     /// TODO: Update summary.\r
  55     /// </summary>\r
  56     public class SnapshotDifferencer\r
  57     {\r
  58         private IEnumerable<ObjectInfo> _previous;\r
  59         private IEnumerable<ObjectInfo> _current;\r
  60         private static ObjectInfo[] _empty = new ObjectInfo[0];\r
  61         private ObjectInfoComparer _comparer = new ObjectInfoComparer();\r
  62 \r
  63         public SnapshotDifferencer()\r
  64         {\r
  65             _previous = new List<ObjectInfo>();\r
  66             _current= new List<ObjectInfo>();\r
  67         }\r
  68 \r
  69 \r
  70         public SnapshotDifferencer(IEnumerable<ObjectInfo> previous,IEnumerable<ObjectInfo> current  )\r
  71         {\r
  72             _previous = previous ?? new List<ObjectInfo>();\r
  73             _current= current ?? new List<ObjectInfo>();\r
  74         }\r
  75         public SnapshotDifferencer Post(IEnumerable<ObjectInfo> list)\r
  76         {\r
  77             _previous = _current;\r
  78             _current = list ?? new List<ObjectInfo>();\r
  79             return this;\r
  80         }\r
  81         \r
  82         public IEnumerable<ObjectInfo> Deleted\r
  83         {\r
  84             get { return _previous.Except(_current,_comparer); }\r
  85         }\r
  86         public IEnumerable<ObjectInfo> Created\r
  87         {\r
  88             get { return _current.Except(_previous,_comparer); }\r
  89         }\r
  90         public IEnumerable<ObjectInfo> Changed\r
  91         {\r
  92             get\r
  93             {\r
  94                 var changes = from newItem in _current \r
  95                               let oldItem=_previous.FirstOrDefault(old=>_comparer.Equals(old,newItem))\r
  96                               where oldItem !=null &&\r
  97                                     newItem.Hash != oldItem.Hash\r
  98                               select newItem;\r
  99                 return changes;\r
 100             }\r
 101         }\r
 102         public IEnumerable<ObjectInfo> Unchanged\r
 103         {\r
 104             get\r
 105             {\r
 106                 var unChanged = from newItem in _current\r
 107                               let oldItem = _previous.FirstOrDefault(old => _comparer.Equals(old, newItem))\r
 108                               where oldItem != null &&\r
 109                                     newItem.Hash == oldItem.Hash\r
 110                               select newItem;\r
 111                 return unChanged;\r
 112             }\r
 113         }\r
 114     }\r
 115 \r
 116     public class AccountsDifferencer\r
 117     {\r
 118         ConcurrentDictionary<string, SnapshotDifferencer> _differencers = new ConcurrentDictionary<string, SnapshotDifferencer>();\r
 119 \r
 120         public ConcurrentDictionary<string, SnapshotDifferencer> Differencers { get { return _differencers; } }\r
 121 \r
 122         public SnapshotDifferencer PostSnapshot(AccountInfo accountInfo, List<ObjectInfo> cleanRemotes)\r
 123         {\r
 124             SnapshotDifferencer differencer;\r
 125             if (!_differencers.TryGetValue(accountInfo.UserName, out differencer))\r
 126             {\r
 127                 differencer = new SnapshotDifferencer();\r
 128                 _differencers[accountInfo.UserName] = differencer;\r
 129             }\r
 130             differencer.Post(cleanRemotes);\r
 131             return differencer;\r
 132         }\r
 133 \r
 134     }\r
 135 }\r