forked from danzel/Npgsql
-
Notifications
You must be signed in to change notification settings - Fork 0
Expand file tree
/
Copy pathNpgsqlAsciiRow.cs
More file actions
175 lines (158 loc) · 5.59 KB
/
NpgsqlAsciiRow.cs
File metadata and controls
175 lines (158 loc) · 5.59 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
// created on 13/6/2002 at 21:06
// Npgsql.NpgsqlAsciiRow.cs
//
// Author:
// Francisco Jr. (fxjrlists@yahoo.com.br)
//
// Copyright (C) 2002 The Npgsql Development Team
// npgsql-general@gborg.postgresql.org
// http://gborg.postgresql.org/project/npgsql/projdisplay.php
//
// Permission to use, copy, modify, and distribute this software and its
// documentation for any purpose, without fee, and without a written
// agreement is hereby granted, provided that the above copyright notice
// and this paragraph and the following two paragraphs appear in all copies.
//
// IN NO EVENT SHALL THE NPGSQL DEVELOPMENT TEAM BE LIABLE TO ANY PARTY
// FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES,
// INCLUDING LOST PROFITS, ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS
// DOCUMENTATION, EVEN IF THE NPGSQL DEVELOPMENT TEAM HAS BEEN ADVISED OF
// THE POSSIBILITY OF SUCH DAMAGE.
//
// THE NPGSQL DEVELOPMENT TEAM SPECIFICALLY DISCLAIMS ANY WARRANTIES,
// INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
// AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
// ON AN "AS IS" BASIS, AND THE NPGSQL DEVELOPMENT TEAM HAS NO OBLIGATIONS
// TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
using System;
using System.Data;
using System.IO;
using NpgsqlTypes;
namespace Npgsql
{
/// <summary>
/// Implements <see cref="RowReader"/> for version 3 of the protocol.
/// </summary>
internal sealed class StringRowReader : RowReader
{
private readonly int _messageSize;
private int? _nextFieldSize = null;
public StringRowReader(Stream inputStream)
: base(inputStream)
{
_messageSize = PGUtil.ReadInt32(inputStream);
}
public override void SetRowDescription(NpgsqlRowDescription rowDesc)
{
if (PGUtil.ReadInt16(Stream) != rowDesc.NumFields)
{
throw new DataException();
}
_rowDesc = rowDesc;
}
protected override object ReadNext()
{
int fieldSize = GetThisFieldCount();
if (fieldSize >= _messageSize)
{
AbandonShip();
}
_nextFieldSize = null;
// Check if this field is null
if (fieldSize == -1) // Null value
{
return DBNull.Value;
}
NpgsqlRowDescription.FieldData field_descr = FieldData;
byte[] buffer = new byte[fieldSize];
PGUtil.CheckedStreamRead(Stream, buffer, 0, fieldSize);
try
{
if (field_descr.FormatCode == FormatCode.Text)
{
return
NpgsqlTypesHelper.ConvertBackendStringToSystemType(field_descr.TypeInfo, buffer,
field_descr.TypeSize, field_descr.TypeModifier);
}
else
{
return
NpgsqlTypesHelper.ConvertBackendBytesToSystemType(field_descr.TypeInfo, buffer, fieldSize,
field_descr.TypeModifier);
}
}
catch (InvalidCastException ice)
{
return ice;
}
catch (Exception ex)
{
return new InvalidCastException(ex.Message, ex);
}
}
private void AbandonShip()
{
//field size will always be smaller than message size
//but if we fall out of sync with the stream due to an error then we will probably hit
//such a situation soon as bytes from elsewhere in the stream get interpreted as a size.
//so if we see this happens, we know we've lost the stream - our best option is to just give up on it,
//and have the connector recovered later.
try
{
Stream
.WriteBytes((byte)FrontEndMessageCode.Termination)
.WriteInt32(4)
.Flush();
}
catch
{
}
try
{
Stream.Close();
}
catch
{
}
throw new DataException();
}
protected override void SkipOne()
{
int fieldSize = GetThisFieldCount();
if (fieldSize >= _messageSize)
{
AbandonShip();
}
_nextFieldSize = null;
PGUtil.EatStreamBytes(Stream, fieldSize);
}
public override bool IsNextDBNull
{
get { return GetThisFieldCount() == -1; }
}
private int GetThisFieldCount()
{
return (_nextFieldSize = _nextFieldSize ?? PGUtil.ReadInt32(Stream)).Value;
}
protected override int GetNextFieldCount()
{
int ret = GetThisFieldCount();
_nextFieldSize = null;
return ret;
}
public override void Dispose()
{
if (_rowDesc == null)
{
// If _rowdesc is null, then only the message length integer has been read;
// read the entire message and disgard it.
PGUtil.EatStreamBytes(Stream, this._messageSize - 4);
}
else
{
CurrentStreamer = null;
Skip(_rowDesc.NumFields - _currentField - 1);
}
}
}
}