class/Npgsql/Npgsql/NpgsqlCopyInStream.cs

   1 // Npgsql.NpgsqlCopyInStream.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         /// Stream for writing data to a table on a PostgreSQL version 7.4 or newer database during an active COPY FROM STDIN operation.
  35         /// <b>Passes data exactly as is and when given</b>, so see to it that you use server encoding, correct format and reasonably sized writes!
  36         /// </summary>
  37         internal class NpgsqlCopyInStream : Stream
  38         {
  39                 private NpgsqlConnector _context;
  40                 private long _bytesPassed = 0;
  41
  42                 /// <summary>
  43                 /// True while this stream can be used to write copy data to server
  44                 /// </summary>
  45                 private bool IsActive
  46                 {
  47                         get { return _context != null && _context.CurrentState is NpgsqlCopyInState && _context.Mediator.CopyStream == this; }
  48                 }
  49
  50                 /// <summary>
  51                 /// Created only by NpgsqlCopyInState.StartCopy()
  52                 /// </summary>
  53                 internal NpgsqlCopyInStream(NpgsqlConnector context)
  54                 {
  55                         _context = context;
  56                 }
  57
  58                 /// <summary>
  59                 /// False
  60                 /// </summary>
  61                 public override bool CanRead
  62                 {
  63                         get { return false; }
  64                 }
  65
  66                 /// <summary>
  67                 /// True
  68                 /// </summary>
  69                 public override bool CanWrite
  70                 {
  71                         get { return true; }
  72                 }
  73
  74                 /// <summary>
  75                 /// False
  76                 /// </summary>
  77                 public override bool CanSeek
  78                 {
  79                         get { return false; }
  80                 }
  81
  82                 /// <summary>
  83                 /// Number of bytes written so far
  84                 /// </summary>
  85                 public override long Length
  86                 {
  87                         get { return _bytesPassed; }
  88                 }
  89
  90                 /// <summary>
  91                 /// Number of bytes written so far; not settable
  92                 /// </summary>
  93                 public override long Position
  94                 {
  95                         get { return _bytesPassed; }
  96                         set { throw new NotSupportedException("Tried to set Position of network stream " + this); }
  97                 }
  98
  99                 /// <summary>
 100                 /// Successfully completes copying data to server. Returns after operation is finished.
 101                 /// Does nothing if this stream is not the active copy operation writer.
 102                 /// </summary>
 103                 public override void Close()
 104                 {
 105                         if (_context != null)
 106                         {
 107                                 if (IsActive)
 108                                 {
 109                                         _context.CurrentState.SendCopyDone(_context);
 110                                 }
 111                                 if (_context.Mediator.CopyStream == this)
 112                                 {
 113                                         _context.Mediator.CopyStream = null;
 114                                 }
 115                                 _context = null;
 116                         }
 117                 }
 118
 119                 /// <summary>
 120                 /// Withdraws an already started copy operation. The operation will fail with given error message.
 121                 /// Does nothing if this stream is not the active copy operation writer.
 122                 /// </summary>
 123                 public void Cancel(string message)
 124                 {
 125                         if (IsActive)
 126                         {
 127                                 NpgsqlConnector c = _context;
 128                                 _context = null;
 129                                 c.Mediator.CopyStream = null;
 130                                 c.CurrentState.SendCopyFail(_context, message ?? "Cancel Copy");
 131                         }
 132                 }
 133
 134                 /// <summary>
 135                 /// Writes given bytes to server.
 136                 /// Fails if this stream is not the active copy operation writer.
 137                 /// </summary>
 138                 public override void Write(byte[] buf, int off, int len)
 139                 {
 140                         if (! IsActive)
 141                         {
 142                                 throw new ObjectDisposedException("Writing to closed " + this);
 143                         }
 144                         _context.CurrentState.SendCopyData(_context, buf, off, len);
 145                         _bytesPassed += len;
 146                 }
 147
 148                 /// <summary>
 149                 /// Flushes stream contents to server.
 150                 /// Fails if this stream is not the active copy operation writer.
 151                 /// </summary>
 152                 public override void Flush()
 153                 {
 154                         if (! IsActive)
 155                         {
 156                                 throw new ObjectDisposedException("Flushing closed " + this);
 157                         }
 158                         _context.Stream.Flush();
 159                 }
 160
 161                 /// <summary>
 162                 /// Not readable
 163                 /// </summary>
 164                 public override int Read(byte[] buf, int off, int len)
 165                 {
 166                         throw new NotSupportedException("Tried to read non-readable " + this);
 167                 }
 168
 169                 /// <summary>
 170                 /// Not seekable
 171                 /// </summary>
 172                 public override long Seek(long pos, SeekOrigin so)
 173                 {
 174                         throw new NotSupportedException("Tried to seek non-seekable " + this);
 175                 }
 176
 177                 /// <summary>
 178                 /// Not supported
 179                 /// </summary>
 180                 public override void SetLength(long len)
 181                 {
 182                         throw new NotSupportedException("Tried to set length of network stream " + this);
 183                 }
 184         }
 185 }