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

   1 //
   2 // NewExpression.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.Collections.ObjectModel;
  31 using System.Reflection;
  32 using System.Reflection.Emit;
  33
  34 namespace System.Linq.Expressions {
  35
  36         public sealed class NewExpression : Expression {
  37
  38                 ConstructorInfo constructor;
  39                 ReadOnlyCollection<Expression> arguments;
  40                 ReadOnlyCollection<MemberInfo> members;
  41
  42                 public ConstructorInfo Constructor {
  43                         get { return constructor; }
  44                 }
  45
  46                 public ReadOnlyCollection<Expression> Arguments {
  47                         get { return arguments; }
  48                 }
  49
  50                 public ReadOnlyCollection<MemberInfo> Members {
  51                         get { return members; }
  52                 }
  53
  54                 internal NewExpression (Type type, ReadOnlyCollection<Expression> arguments)
  55                         : base (ExpressionType.New, type)
  56                 {
  57                         this.arguments = arguments;
  58                 }
  59
  60                 internal NewExpression (ConstructorInfo constructor, ReadOnlyCollection<Expression> arguments, ReadOnlyCollection<MemberInfo> members)
  61                         : base (ExpressionType.New, constructor.DeclaringType)
  62                 {
  63                         this.constructor = constructor;
  64                         this.arguments = arguments;
  65                         this.members = members;
  66                 }
  67
  68                 internal override void Emit (EmitContext ec)
  69                 {
  70                         var ig = ec.ig;
  71                         var type = this.Type;
  72
  73                         LocalBuilder local = null;
  74                         if (type.IsValueType) {
  75                                 local = ig.DeclareLocal (type);
  76                                 ig.Emit (OpCodes.Ldloca, local);
  77
  78                                 if (constructor == null) {
  79                                         ig.Emit (OpCodes.Initobj, type);
  80                                         ig.Emit (OpCodes.Ldloc, local);
  81                                         return;
  82                                 }
  83                         }
  84
  85                         ec.EmitCollection (arguments);
  86
  87                         if (type.IsValueType) {
  88                                 ig.Emit (OpCodes.Call, constructor);
  89                                 ig.Emit (OpCodes.Ldloc, local);
  90                         } else
  91                                 ig.Emit (OpCodes.Newobj, constructor ?? GetDefaultConstructor (type));
  92                 }
  93
  94                 static ConstructorInfo GetDefaultConstructor (Type type)
  95                 {
  96                         return type.GetConstructor (Type.EmptyTypes);
  97                 }
  98         }
  99 }