mcs/class/Npgsql/Npgsql/NpgsqlCopyOutState.cs

   1 // Npgsql.NpgsqlCopyOutState.cs
   2 //
   3 // Author:
   4 //      Kalle Hallivuori <kato@iki.fi>
   5 //
   6 //      Copyright (C) 2007 The Npgsql Development Team
   7 //      npgsql-general@gborg.postgresql.org
   8 //      http://gborg.postgresql.org/project/npgsql/projdisplay.php
   9 //
  10 // Permission to use, copy, modify, and distribute this software and its
  11 // documentation for any purpose, without fee, and without a written
  12 // agreement is hereby granted, provided that the above copyright notice
  13 // and this paragraph and the following two paragraphs appear in all copies.
  14 //
  15 // IN NO EVENT SHALL THE NPGSQL DEVELOPMENT TEAM BE LIABLE TO ANY PARTY
  16 // FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES,
  17 // INCLUDING LOST PROFITS, ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS
  18 // DOCUMENTATION, EVEN IF THE NPGSQL DEVELOPMENT TEAM HAS BEEN ADVISED OF
  19 // THE POSSIBILITY OF SUCH DAMAGE.
  20 //
  21 // THE NPGSQL DEVELOPMENT TEAM SPECIFICALLY DISCLAIMS ANY WARRANTIES,
  22 // INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
  23 // AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
  24 // ON AN "AS IS" BASIS, AND THE NPGSQL DEVELOPMENT TEAM HAS NO OBLIGATIONS
  25 // TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
  26
  27
  28 using System;
  29 using System.IO;
  30
  31 namespace Npgsql
  32 {
  33         /// <summary>
  34         /// Represents an ongoing COPY TO STDOUT operation.
  35         /// Provides methods to read data from server or end the operation.
  36         /// </summary>
  37         internal sealed class NpgsqlCopyOutState : NpgsqlState
  38         {
  39                 public static readonly NpgsqlCopyOutState Instance = new NpgsqlCopyOutState();
  40
  41                 //private readonly String CLASSNAME = "NpgsqlCopyOutState";
  42
  43                 private NpgsqlCopyFormat _copyFormat = null;
  44
  45                 private NpgsqlCopyOutState()
  46                         : base()
  47                 {
  48                 }
  49
  50                 /// <summary>
  51                 /// Copy format information returned from server.
  52                 /// </summary>
  53                 public override NpgsqlCopyFormat CopyFormat
  54                 {
  55                         get { return _copyFormat; }
  56                 }
  57
  58                 /// <summary>
  59                 /// Called from NpgsqlState.ProcessBackendResponses upon CopyOutResponse.
  60                 /// If CopyStream is already set, it is used to write data received from server, after which the copy ends.
  61                 /// Otherwise CopyStream is set to a readable NpgsqlCopyOutStream that receives data from server.
  62                 /// </summary>
  63                 protected override void StartCopy(NpgsqlConnector context, NpgsqlCopyFormat copyFormat)
  64                 {
  65                         _copyFormat = copyFormat;
  66                         Stream userFeed = context.Mediator.CopyStream;
  67                         if (userFeed == null)
  68                         {
  69                                 context.Mediator.CopyStream = new NpgsqlCopyOutStream(context);
  70                         }
  71                         else
  72                         {
  73                                 byte[] buf;
  74                                 while ((buf = GetCopyData(context)) != null)
  75                                 {
  76                                         userFeed.Write(buf, 0, buf.Length);
  77                                 }
  78                                 userFeed.Close();
  79                         }
  80                 }
  81
  82                 /// <summary>
  83                 /// Called from NpgsqlOutStream.Read to read copy data from server.
  84                 /// </summary>
  85                 public override byte[] GetCopyData(NpgsqlConnector context)
  86                 {
  87                         // polling in COPY would take seconds on Windows
  88                         foreach (IServerResponseObject obj in ProcessBackendResponses_Ver_3(context))
  89                         {
  90                                 if (obj is IDisposable)
  91                                 {
  92                                         (obj as IDisposable).Dispose();
  93                                 }
  94                         }
  95                         return context.Mediator.ReceivedCopyData;
  96                 }
  97         }
  98 }