class/System.Core/System.Linq.Expressions/MemberExpression.cs

   1 //
   2 // MemberExpression.cs
   3 //
   4 // Author:
   5 //   Jb Evain (jbevain@novell.com)
   6 //
   7 // (C) 2008 Novell, Inc. (http://www.novell.com)
   8 //
   9 // Permission is hereby granted, free of charge, to any person obtaining
  10 // a copy of this software and associated documentation files (the
  11 // "Software"), to deal in the Software without restriction, including
  12 // without limitation the rights to use, copy, modify, merge, publish,
  13 // distribute, sublicense, and/or sell copies of the Software, and to
  14 // permit persons to whom the Software is furnished to do so, subject to
  15 // the following conditions:
  16 //
  17 // The above copyright notice and this permission notice shall be
  18 // included in all copies or substantial portions of the Software.
  19 //
  20 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  21 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  22 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  23 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  24 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  25 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  26 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  27 //
  28
  29 using System;
  30 using System.Reflection;
  31 using System.Reflection.Emit;
  32
  33 namespace System.Linq.Expressions {
  34
  35         public sealed class MemberExpression : Expression {
  36
  37                 Expression expression;
  38                 MemberInfo member;
  39
  40                 public Expression Expression {
  41                         get { return expression; }
  42                 }
  43
  44                 public MemberInfo Member {
  45                         get { return member; }
  46                 }
  47
  48                 internal MemberExpression (Expression expression, MemberInfo member, Type type)
  49                         : base (ExpressionType.MemberAccess, type)
  50                 {
  51                         this.expression = expression;
  52                         this.member = member;
  53                 }
  54
  55                 internal override void Emit (EmitContext ec)
  56                 {
  57                         member.OnFieldOrProperty (
  58                                 field => EmitFieldAccess (ec, field),
  59                                 prop => EmitPropertyAccess (ec, prop));
  60                 }
  61
  62                 void EmitPropertyAccess (EmitContext ec, PropertyInfo property)
  63                 {
  64                         var getter = property.GetGetMethod (true);
  65                         if (!getter.IsStatic)
  66                                 ec.EmitLoadSubject (expression);
  67
  68                         ec.EmitCall (getter);
  69                 }
  70
  71                 void EmitFieldAccess (EmitContext ec, FieldInfo field)
  72                 {
  73                         if (!field.IsStatic) {
  74                                 ec.EmitLoadSubject (expression);
  75                                 ec.ig.Emit (OpCodes.Ldfld, field);
  76                         } else
  77                                 ec.ig.Emit (OpCodes.Ldsfld, field);
  78                 }
  79         }
  80 }