mcs/class/System.Data/System.Data.Common/DbEnumerator.cs

   1 //
   2 // System.Data.SqlClient.DbEnumerator.cs
   3 //
   4 // Author:
   5 //   Tim Coleman (tim@timcoleman.com)
   6 //
   7 // Copyright (C) Tim Coleman, 2002
   8 //
   9
  10 //
  11 // Copyright (C) 2004 Novell, Inc (http://www.novell.com)
  12 //
  13 // Permission is hereby granted, free of charge, to any person obtaining
  14 // a copy of this software and associated documentation files (the
  15 // "Software"), to deal in the Software without restriction, including
  16 // without limitation the rights to use, copy, modify, merge, publish,
  17 // distribute, sublicense, and/or sell copies of the Software, and to
  18 // permit persons to whom the Software is furnished to do so, subject to
  19 // the following conditions:
  20 //
  21 // The above copyright notice and this permission notice shall be
  22 // included in all copies or substantial portions of the Software.
  23 //
  24 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  25 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  26 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  27 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  28 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  29 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  30 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  31 //
  32
  33 using System;
  34 using System.Collections;
  35 using System.ComponentModel;
  36 using System.Data;
  37
  38 namespace System.Data.Common {
  39         public class DbEnumerator : IEnumerator
  40         {
  41                 #region Fields
  42
  43                 readonly IDataReader reader;
  44                 readonly bool closeReader;
  45                 readonly SchemaInfo [] schema;
  46
  47                 #endregion // Fields
  48
  49                 #region Constructors
  50
  51                 public DbEnumerator (IDataReader reader)
  52                         : this (reader, false)
  53                 {
  54                 }
  55
  56                 public DbEnumerator (IDataReader reader, bool closeReader)
  57                 {
  58                         this.reader = reader;
  59                         this.closeReader = closeReader;
  60                         this.schema = LoadSchema (reader);
  61                 }
  62
  63                 #endregion // Constructors
  64
  65                 #region Properties
  66
  67                 public object Current {
  68                         get {
  69                                 // DbDataRecordImpl does not do copy of the array
  70                                 // and MoveNext would overwrite any previously filled data
  71                                 var values = new object [reader.FieldCount];
  72                                 reader.GetValues (values);
  73
  74                                 // TODO: Should not allocate on every property call
  75                                 return new DbDataRecordImpl (schema, values);
  76                         }
  77                 }
  78
  79                 #endregion // Properties
  80
  81                 #region Methods
  82
  83                 private static SchemaInfo[] LoadSchema (IDataReader reader)
  84                 {
  85                         int fieldCount = reader.FieldCount;
  86                         SchemaInfo[] schema = new SchemaInfo [fieldCount];
  87
  88                         for(int i=0; i < fieldCount; i++) {
  89                                 SchemaInfo columnSchema = new SchemaInfo ();
  90
  91                                 columnSchema.ColumnName = reader.GetName(i);
  92                                 columnSchema.ColumnOrdinal = i;
  93                                 columnSchema.DataTypeName = reader.GetDataTypeName (i);
  94                                 columnSchema.FieldType = reader.GetFieldType (i);
  95
  96                                 schema [i] = columnSchema;
  97                         }
  98
  99                         return schema;
 100                 }
 101
 102                 public bool MoveNext ()
 103                 {
 104                         if (reader.Read ())
 105                                 return true;
 106                         if (closeReader)
 107                                 reader.Close ();
 108                         return false;
 109                 }
 110
 111                 [EditorBrowsable (EditorBrowsableState.Never)]
 112                 public void Reset ()
 113                 {
 114                         throw new NotSupportedException ();
 115                 }
 116
 117                 #endregion // Methods
 118         }
 119 }