class/Npgsql/Npgsql/NpgsqlCopyInState.cs

   1 // Npgsql.NpgsqlCopyInState.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 FROM STDIN operation.
  35         /// Provides methods to push data to server and end or cancel the operation.
  36         /// </summary>
  37         internal sealed class NpgsqlCopyInState : NpgsqlState
  38         {
  39                 public static readonly NpgsqlCopyInState Instance = new NpgsqlCopyInState();
  40
  41                 private NpgsqlCopyFormat _copyFormat = null;
  42
  43                 private NpgsqlCopyInState()
  44                         : base()
  45                 {
  46                 }
  47
  48                 /// <summary>
  49                 /// Copy format information returned from server.
  50                 /// </summary>
  51                 public override NpgsqlCopyFormat CopyFormat
  52                 {
  53                         get { return _copyFormat; }
  54                 }
  55
  56                 /// <summary>
  57                 /// Called from NpgsqlState.ProcessBackendResponses upon CopyInResponse.
  58                 /// If CopyStream is already set, it is used to read data to push to server, after which the copy is completed.
  59                 /// Otherwise CopyStream is set to a writable NpgsqlCopyInStream that calls SendCopyData each time it is written to.
  60                 /// </summary>
  61                 protected override void StartCopy(NpgsqlConnector context, NpgsqlCopyFormat copyFormat)
  62                 {
  63                         _copyFormat = copyFormat;
  64                         Stream userFeed = context.Mediator.CopyStream;
  65                         if (userFeed == null)
  66                         {
  67                                 context.Mediator.CopyStream = new NpgsqlCopyInStream(context);
  68                         }
  69                         else
  70                         {
  71                                 // copy all of user feed to server at once
  72                                 int bufsiz = context.Mediator.CopyBufferSize;
  73                                 byte[] buf = new byte[bufsiz];
  74                                 int len;
  75                                 while ((len = userFeed.Read(buf, 0, bufsiz)) > 0)
  76                                 {
  77                                         SendCopyData(context, buf, 0, len);
  78                                 }
  79                                 SendCopyDone(context);
  80                         }
  81                 }
  82
  83                 /// <summary>
  84                 /// Sends given packet to server as a CopyData message.
  85                 /// Does not check for notifications! Use another thread for that.
  86                 /// </summary>
  87                 public override void SendCopyData(NpgsqlConnector context, byte[] buf, int off, int len)
  88                 {
  89                         Stream toServer = context.Stream;
  90                         toServer.WriteByte((byte) FrontEndMessageCode.CopyData);
  91                         PGUtil.WriteInt32(toServer, len + 4);
  92                         toServer.Write(buf, off, len);
  93                 }
  94
  95                 /// <summary>
  96                 /// Sends CopyDone message to server. Handles responses, ie. may throw an exception.
  97                 /// </summary>
  98                 public override void SendCopyDone(NpgsqlConnector context)
  99                 {
 100                         Stream toServer = context.Stream;
 101                         toServer.WriteByte((byte) FrontEndMessageCode.CopyDone);
 102                         PGUtil.WriteInt32(toServer, 4); // message without data
 103                         toServer.Flush();
 104                         ProcessBackendResponses(context);
 105                 }
 106
 107                 /// <summary>
 108                 /// Sends CopyFail message to server. Handles responses, ie. should always throw an exception:
 109                 /// in CopyIn state the server responds to CopyFail with an error response;
 110                 /// outside of a CopyIn state the server responds to CopyFail with an error response;
 111                 /// without network connection or whatever, there's going to eventually be a failure, timeout or user intervention.
 112                 /// </summary>
 113                 public override void SendCopyFail(NpgsqlConnector context, String message)
 114                 {
 115                         Stream toServer = context.Stream;
 116                         toServer.WriteByte((byte) FrontEndMessageCode.CopyFail);
 117                         byte[] buf = ENCODING_UTF8.GetBytes((message ?? string.Empty) + '\x00');
 118                         PGUtil.WriteInt32(toServer, 4 + buf.Length);
 119                         toServer.Write(buf, 0, buf.Length);
 120                         toServer.Flush();
 121                         ProcessBackendResponses(context);
 122                 }
 123         }
 124 }