2 // QueryableTransformer.cs
5 // Roei Erez (roeie@mainsoft.com)
6 // Jb Evain (jbevain@novell.com)
8 // Copyright (C) 2008 Novell, Inc (http://www.novell.com)
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:
18 // The above copyright notice and this permission notice shall be
19 // included in all copies or substantial portions of the Software.
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.
31 using System.Collections;
32 using System.Collections.Generic;
33 using System.Collections.ObjectModel;
35 using System.Linq.Expressions;
36 using System.Reflection;
37 using System.Runtime.CompilerServices;
39 namespace System.Linq {
41 class QueryableTransformer : ExpressionTransformer {
43 protected override Expression VisitMethodCall (MethodCallExpression methodCall)
45 if (IsQueryableExtension (methodCall.Method))
46 return ReplaceQueryableMethod (methodCall);
48 return base.VisitMethodCall (methodCall);
51 protected override Expression VisitLambda (LambdaExpression lambda)
56 protected override Expression VisitConstant (ConstantExpression constant)
58 var qe = constant.Value as IQueryableEnumerable;
62 return Expression.Constant (qe.GetEnumerable ());
65 static bool IsQueryableExtension (MethodInfo method)
67 return HasExtensionAttribute (method) &&
68 method.GetParameters () [0].ParameterType.IsAssignableTo (typeof (IQueryable));
71 static bool HasExtensionAttribute (MethodInfo method)
73 return method.GetCustomAttributes (typeof (ExtensionAttribute), false).Length > 0;
76 MethodCallExpression ReplaceQueryableMethod (MethodCallExpression old)
78 Expression target = null;
79 if (old.Object != null)
80 target = Visit (old.Object);
82 var method = ReplaceQueryableMethod (old.Method);
83 var parameters = method.GetParameters ();
84 var arguments = new Expression [old.Arguments.Count];
86 for (int i = 0; i < arguments.Length; i++) {
87 arguments [i] = UnquoteIfNeeded (
88 Visit (old.Arguments [i]),
89 parameters [i].ParameterType);
92 return Expression.Call (target, method, arguments);
95 static Expression UnquoteIfNeeded (Expression expression, Type delegateType)
97 if (expression.NodeType != ExpressionType.Quote)
100 var lambda = (LambdaExpression) ((UnaryExpression) expression).Operand;
101 if (lambda.Type == delegateType)
107 static Type GetTargetDeclaringType (MethodInfo method)
109 return method.DeclaringType == typeof (Queryable) ? typeof (Enumerable) : method.DeclaringType;
112 static MethodInfo ReplaceQueryableMethod (MethodInfo method)
114 var target_type = GetTargetDeclaringType (method);
115 var result = GetMatchingMethod (method, target_type);
120 throw new InvalidOperationException (
122 "There is no method {0} on type {1} that matches the specified arguments",
124 target_type.FullName));
127 static MethodInfo GetMatchingMethod (MethodInfo method, Type declaring)
129 foreach (var candidate in declaring.GetMethods ()) {
130 if (!MethodMatch (candidate, method))
133 if (method.IsGenericMethod)
134 return candidate.MakeGenericMethodFrom (method);
142 static bool MethodMatch (MethodInfo candidate, MethodInfo method)
144 if (candidate.Name != method.Name)
147 if (!HasExtensionAttribute (candidate))
150 var parameters = method.GetParameterTypes ();
152 if (parameters.Length != candidate.GetParameters ().Length)
155 if (method.IsGenericMethod) {
156 if (!candidate.IsGenericMethod)
159 if (candidate.GetGenericArguments ().Length != method.GetGenericArguments ().Length)
162 candidate = candidate.MakeGenericMethodFrom (method);
165 if (!TypeMatch (candidate.ReturnType, method.ReturnType))
168 var candidate_parameters = candidate.GetParameterTypes ();
170 if (candidate_parameters [0] != GetComparableType (parameters [0]))
173 for (int i = 1; i < candidate_parameters.Length; ++i)
174 if (!TypeMatch (candidate_parameters [i], parameters [i]))
180 static bool TypeMatch (Type candidate, Type type)
182 if (candidate == type)
185 return candidate == GetComparableType (type);
188 static Type GetComparableType (Type type)
190 if (type.IsGenericInstanceOf (typeof (IQueryable<>)))
191 type = typeof (IEnumerable<>).MakeGenericTypeFrom (type);
192 else if (type.IsGenericInstanceOf (typeof (IOrderedQueryable<>)))
193 type = typeof (IOrderedEnumerable<>).MakeGenericTypeFrom (type);
194 else if (type.IsGenericInstanceOf (typeof (Expression<>)))
195 type = type.GetFirstGenericArgument ();
196 else if (type == typeof (IQueryable))
197 type = typeof (IEnumerable);