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
|
//------------------------------------------------------------------------------
// <copyright file="DataReaderContainer.cs" company="Microsoft">
// Copyright (c) Microsoft Corporation. All rights reserved.
// </copyright>
// <owner current="true" primary="true">Microsoft</owner>
//------------------------------------------------------------------------------
namespace System.Data.ProviderBase {
using System;
using System.Data;
using System.Data.Common;
using System.Diagnostics;
internal abstract class DataReaderContainer {
protected readonly IDataReader _dataReader;
protected int _fieldCount;
static internal DataReaderContainer Create(IDataReader dataReader, bool returnProviderSpecificTypes) {
if (returnProviderSpecificTypes) {
DbDataReader providerSpecificDataReader = (dataReader as DbDataReader);
if (null != providerSpecificDataReader) {
return new ProviderSpecificDataReader(dataReader, providerSpecificDataReader);
}
}
return new CommonLanguageSubsetDataReader(dataReader);
}
protected DataReaderContainer(IDataReader dataReader) {
Debug.Assert(null != dataReader, "null dataReader");
_dataReader = dataReader;
}
internal int FieldCount {
get {
return _fieldCount;
}
}
internal abstract bool ReturnProviderSpecificTypes { get; }
protected abstract int VisibleFieldCount { get; }
internal abstract Type GetFieldType(int ordinal);
internal abstract object GetValue(int ordinal);
internal abstract int GetValues(object[] values);
internal string GetName(int ordinal) {
string fieldName = _dataReader.GetName(ordinal);
Debug.Assert(null != fieldName, "null GetName");
return ((null != fieldName) ? fieldName : "");
}
internal DataTable GetSchemaTable() {
return _dataReader.GetSchemaTable();
}
internal bool NextResult() {
_fieldCount = 0;
if (_dataReader.NextResult()) {
_fieldCount = VisibleFieldCount;
return true;
}
return false;
}
internal bool Read() {
return _dataReader.Read();
}
private sealed class ProviderSpecificDataReader : DataReaderContainer {
private DbDataReader _providerSpecificDataReader;
internal ProviderSpecificDataReader(IDataReader dataReader, DbDataReader dbDataReader) : base(dataReader) {
Debug.Assert(null != dataReader, "null dbDataReader");
_providerSpecificDataReader = dbDataReader;
_fieldCount = VisibleFieldCount;
}
internal override bool ReturnProviderSpecificTypes {
get {
return true;
}
}
protected override int VisibleFieldCount {
get {
int fieldCount = _providerSpecificDataReader.VisibleFieldCount;
Debug.Assert(0 <= fieldCount, "negative FieldCount");
return ((0 <= fieldCount) ? fieldCount : 0);
}
}
internal override Type GetFieldType(int ordinal) {
Type fieldType = _providerSpecificDataReader.GetProviderSpecificFieldType(ordinal);
Debug.Assert(null != fieldType, "null FieldType");
return fieldType;
}
internal override object GetValue(int ordinal) {
return _providerSpecificDataReader.GetProviderSpecificValue(ordinal);
}
internal override int GetValues(object[] values) {
return _providerSpecificDataReader.GetProviderSpecificValues(values);
}
}
private sealed class CommonLanguageSubsetDataReader : DataReaderContainer {
internal CommonLanguageSubsetDataReader(IDataReader dataReader ) : base(dataReader) {
_fieldCount = VisibleFieldCount;
}
internal override bool ReturnProviderSpecificTypes {
get {
return false;
}
}
protected override int VisibleFieldCount {
get {
int fieldCount = _dataReader.FieldCount;
Debug.Assert(0 <= fieldCount, "negative FieldCount");
return ((0 <= fieldCount) ? fieldCount : 0);
}
}
internal override Type GetFieldType(int ordinal) {
return _dataReader.GetFieldType(ordinal);
}
internal override object GetValue(int ordinal) {
return _dataReader.GetValue(ordinal);
}
internal override int GetValues(object[] values) {
return _dataReader.GetValues(values);
}
}
}
}
|
