mcs/class/System.Core/System.Linq.Expressions/LambdaExpression.cs

   1 //
   2 // LambdaExpression.cs
   3 //
   4 // Author:
   5 //   Jb Evain (jbevain@novell.com)
   6 //   Miguel de Icaza (miguel@novell.com)
   7 //
   8 // (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.ObjectModel;
  32 using System.Collections.Generic;
  33 using System.Reflection;
  34 using System.Reflection.Emit;
  35 using System.Threading;
  36
  37 namespace System.Linq.Expressions {
  38
  39         internal class EmitContext {
  40                 internal LambdaExpression Owner;
  41                 internal Type [] ParamTypes;
  42                 internal DynamicMethod Method;
  43                 internal ILGenerator ig;
  44
  45                 // When debugging:
  46                 internal AssemblyBuilder ab;
  47                 internal TypeBuilder tb;
  48                 internal MethodBuilder mb;
  49
  50                 static object mlock = new object ();
  51                 static int method_count;
  52                 static string GenName ()
  53                 {
  54                         lock (mlock){
  55                                 return "<LINQ-" + method_count++ + ">";
  56                         }
  57                 }
  58
  59                 public EmitContext (LambdaExpression owner)
  60                 {
  61                         Owner = owner;
  62
  63                         ParamTypes = new Type [Owner.parameters.Count];
  64                         for (int i = 0; i < Owner.parameters.Count; i++)
  65                                 ParamTypes [i] = Owner.parameters [i].Type;
  66
  67                         //
  68                         // We probably want to use the 3.5 new API calls to associate
  69                         // the method with the "sandboxed" Assembly, instead am currently
  70                         // dumping these types in this class
  71                         //
  72                         Type owner_of_code = typeof (EmitContext);
  73
  74
  75                         //
  76                         // FIXME: Need to force this to be verifiable, see:
  77                         // https://bugzilla.novell.com/show_bug.cgi?id=355005
  78                         //
  79                         string name = GenName ();
  80                         if (Environment.GetEnvironmentVariable ("LINQ_DBG") != null){
  81                                 string fname = "linq" + (method_count-1) + ".dll";
  82                                 ab = Thread.GetDomain ().DefineDynamicAssembly (new AssemblyName (fname),
  83                                                                                 AssemblyBuilderAccess.RunAndSave, "/tmp");
  84                                 ModuleBuilder b = ab.DefineDynamicModule (fname, fname);
  85                                 tb = b.DefineType ("LINQ", TypeAttributes.Public);
  86                                 mb = tb.DefineMethod ("A", MethodAttributes.Static, Owner.Type, ParamTypes);
  87                                 ig = mb.GetILGenerator ();
  88                         } else {
  89                                 Method = new DynamicMethod (name, Owner.Type, ParamTypes, owner_of_code);
  90
  91                                 ig = Method.GetILGenerator ();
  92                         }
  93                 }
  94
  95                 internal Delegate CreateDelegate ()
  96                 {
  97                         if (ab != null){
  98                                 tb.CreateType ();
  99                                 ab.Save ("linq" + (method_count-1) + ".dll");
 100
 101                                 // This does not work, need to figure out why, for now
 102                                 // makes debugging harder (only one linq file will work unless
 103                                 // you do not compile them
 104                                 Delegate d = Delegate.CreateDelegate (Owner.delegate_type, tb, mb, true);
 105
 106                                 ab = null;
 107                                 tb = null;
 108
 109                                 //Console.WriteLine ("got: {0}", d);
 110                                 return null;
 111                         }
 112                         return Method.CreateDelegate (Owner.delegate_type);
 113                 }
 114
 115                 internal int GetParameterPosition (ParameterExpression p)
 116                 {
 117                         ReadOnlyCollection<ParameterExpression> pars = Owner.Parameters;
 118
 119                         for (int i = 0; i < pars.Count; i++){
 120                                 if (pars [i] == p)
 121                                         return i;
 122                         }
 123                         throw new InvalidOperationException ("Parameter not in scope");
 124                 }
 125         }
 126
 127         public class LambdaExpression : Expression {
 128
 129                 //
 130                 // LambdaExpression parameters
 131                 //
 132                 Expression body;
 133                 internal ReadOnlyCollection<ParameterExpression> parameters;
 134                 internal Type delegate_type;
 135
 136                 // This is set during compilation
 137                 Delegate lambda_delegate;
 138
 139                 static bool CanAssign (Type target, Type source)
 140                 {
 141                         // This catches object and value type mixage, type compatibility is handled later
 142                         if (target.IsValueType ^ source.IsValueType)
 143                                 return false;
 144
 145                         return target.IsAssignableFrom (source);
 146                 }
 147
 148                 internal LambdaExpression (Type delegateType, Expression body, ReadOnlyCollection<ParameterExpression> parameters)
 149                         : base (ExpressionType.Lambda, body.Type)
 150                 {
 151                         if (!delegateType.IsSubclassOf (typeof (System.Delegate))){
 152                                 throw new ArgumentException ("delegateType");
 153                         }
 154
 155                         MethodInfo [] invokes = delegateType.GetMethods (BindingFlags.Instance | BindingFlags.Public);
 156                         MethodInfo invoke = null;
 157                         foreach (MethodInfo m in invokes)
 158                                 if (m.Name == "Invoke"){
 159                                         invoke = m;
 160                                         break;
 161                                 }
 162                         if (invoke == null)
 163                                 throw new ArgumentException ("delegate must contain an Invoke method", "delegateType");
 164
 165                         ParameterInfo [] invoke_parameters = invoke.GetParameters ();
 166                         if (invoke_parameters.Length != parameters.Count)
 167                                 throw new ArgumentException ("Different number of arguments in delegate {0}", "delegateType");
 168
 169                         for (int i = 0; i < invoke_parameters.Length; i++){
 170                                 if (!CanAssign (parameters [i].Type, invoke_parameters [i].ParameterType))
 171                                         throw new ArgumentException (String.Format ("Can not assign a {0} to a {1}", invoke_parameters [i].ParameterType, parameters [i].Type));
 172                         }
 173
 174                         if (!CanAssign (invoke.ReturnType, body.Type))
 175                                 throw new ArgumentException (String.Format ("body type {0} can not be assigned to {1}", body.Type, invoke.ReturnType));
 176
 177                         this.body = body;
 178                         this.parameters = parameters;
 179                         delegate_type = delegateType;
 180                 }
 181
 182                 public Expression Body {
 183                         get { return body; }
 184                 }
 185
 186                 public ReadOnlyCollection<ParameterExpression> Parameters {
 187                         get { return parameters; }
 188                 }
 189
 190                 internal override void Emit (EmitContext ec)
 191                 {
 192                         throw new NotImplementedException ();
 193                 }
 194
 195                 public Delegate Compile ()
 196                 {
 197                         if (lambda_delegate == null){
 198                                 EmitContext ec = new EmitContext (this);
 199
 200                                 body.Emit (ec);
 201
 202                                 ec.ig.Emit (OpCodes.Ret);
 203
 204                                 lambda_delegate = ec.CreateDelegate ();
 205                         }
 206                         return lambda_delegate;
 207                 }
 208         }
 209 }