class/System.Core/System.Linq/QueryableEnumerable.cs

   1 //
   2 // QueryableEnumerable<TElement>.cs
   3 //
   4 // Authors:
   5 //      Roei Erez (roeie@mainsoft.com)
   6 //      Jb Evain (jbevain@novell.com)
   7 //
   8 // Copyright (C) 2008 Novell, Inc (http://www.novell.com)
   9 //
  10 // Permission is hereby granted, free of charge, to any person obtaining
  11 // a copy of this software and associated documentation files (the
  12 // "Software"), to deal in the Software without restriction, including
  13 // without limitation the rights to use, copy, modify, merge, publish,
  14 // distribute, sublicense, and/or sell copies of the Software, and to
  15 // permit persons to whom the Software is furnished to do so, subject to
  16 // the following conditions:
  17 //
  18 // The above copyright notice and this permission notice shall be
  19 // included in all copies or substantial portions of the Software.
  20 //
  21 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  22 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  23 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  24 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  25 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  26 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  27 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  28 //
  29
  30 using System;
  31 using System.Collections;
  32 using System.Collections.Generic;
  33 using System.Linq;
  34 using System.Linq.Expressions;
  35
  36 namespace System.Linq {
  37
  38         interface IQueryableEnumerable : IQueryable {
  39                 IEnumerable GetEnumerable ();
  40         }
  41
  42         interface IQueryableEnumerable<TElement> : IQueryableEnumerable, IQueryable<TElement>, IOrderedQueryable<TElement> {
  43         }
  44
  45         class QueryableEnumerable<TElement> : IQueryableEnumerable<TElement>, IQueryProvider {
  46
  47                 Expression expression;
  48                 IEnumerable<TElement> enumerable;
  49
  50                 public Type ElementType {
  51                         get { return typeof (TElement); }
  52                 }
  53
  54                 public Expression Expression {
  55                         get { return expression; }
  56                 }
  57
  58                 public IQueryProvider Provider {
  59                         get { return this; }
  60                 }
  61
  62                 public QueryableEnumerable (IEnumerable<TElement> enumerable)
  63                 {
  64                         this.expression = Expression.Constant (this);
  65                         this.enumerable = enumerable;
  66                 }
  67
  68                 public QueryableEnumerable (Expression expression)
  69                 {
  70                         this.expression = expression;
  71                 }
  72
  73                 public IEnumerable GetEnumerable ()
  74                 {
  75                         return enumerable;
  76                 }
  77
  78                 IEnumerator IEnumerable.GetEnumerator ()
  79                 {
  80                         return GetEnumerator ();
  81                 }
  82
  83                 public IEnumerator<TElement> GetEnumerator ()
  84                 {
  85                         return Execute<IEnumerable<TElement>> (expression).GetEnumerator ();
  86                 }
  87
  88                 public IQueryable CreateQuery (Expression expression)
  89                 {
  90                         return (IQueryable) Activator.CreateInstance (
  91                                 typeof (QueryableEnumerable<>).MakeGenericType (
  92                                         expression.Type.GetFirstGenericArgument ()), expression);
  93                 }
  94
  95                 public object Execute (Expression expression)
  96                 {
  97                         var lambda = Expression.Lambda (TransformQueryable (expression));
  98                         return lambda.Compile ().DynamicInvoke ();
  99                 }
 100
 101                 static Expression TransformQueryable (Expression expression)
 102                 {
 103 #if NET_4_0 || BOOTSTRAP_NET_4_0
 104                         throw new NotImplementedException ();
 105 #else
 106                         return new QueryableTransformer ().Transform (expression);
 107 #endif
 108                 }
 109
 110                 public IQueryable<TElem> CreateQuery<TElem> (Expression expression)
 111                 {
 112                         return new QueryableEnumerable<TElem> (expression);
 113                 }
 114
 115                 public TResult Execute<TResult> (Expression expression)
 116                 {
 117                         var lambda = Expression.Lambda<Func<TResult>> (TransformQueryable (expression));
 118                         return lambda.Compile ().Invoke ();
 119                 }
 120         }
 121 }