Tools/Castle.DynamicProxy2/Castle.DynamicProxy/Generators/MethodSignatureComparer.cs

   1 using System;
   2 using System.Collections;
   3 using System.Reflection;
   4 using System.Collections.Generic;
   5
   6 namespace Castle.DynamicProxy.Generators
   7 {
   8         public class MethodSignatureComparer : IEqualityComparer<MethodInfo>
   9         {
  10                 public static readonly MethodSignatureComparer Instance = new MethodSignatureComparer ();
  11
  12                 public bool Equals (MethodInfo x, MethodInfo y)
  13                 {
  14                         if (x == null && y == null)
  15                                 return true;
  16                         else if (x == null || y == null)
  17                                 return false;
  18                         else
  19                                 return x.Name == y.Name && EqualGenericParameters (x, y) && EqualSignatureTypes (x.ReturnType, y.ReturnType) && EqualParameters (x, y);
  20                 }
  21
  22                 private bool EqualGenericParameters (MethodInfo x, MethodInfo y)
  23                 {
  24                         if (x.IsGenericMethod != y.IsGenericMethod)
  25                                 return false;
  26                         if (x.IsGenericMethod)
  27                         {
  28                                 Type[] xArgs = x.GetGenericArguments ();
  29                                 Type[] yArgs = y.GetGenericArguments ();
  30
  31                                 if (xArgs.Length != yArgs.Length)
  32                                         return false;
  33
  34                                 for (int i = 0; i < xArgs.Length; ++i)
  35                                 {
  36                                         if (xArgs[i].IsGenericParameter != yArgs[i].IsGenericParameter)
  37                                                 return false;
  38
  39                                         if (!xArgs[i].IsGenericParameter && !xArgs[i].Equals (yArgs[i]))
  40                                                 return false;
  41                                 }
  42                         }
  43                         return true;
  44                 }
  45
  46                 private bool EqualParameters (MethodInfo x, MethodInfo y)
  47                 {
  48                         ParameterInfo[] xArgs = x.GetParameters ();
  49                         ParameterInfo[] yArgs = y.GetParameters ();
  50
  51                         if (xArgs.Length != yArgs.Length)
  52                                         return false;
  53
  54                         for (int i = 0; i < xArgs.Length; ++i)
  55                         {
  56                                 if (!EqualSignatureTypes(xArgs[i].ParameterType, yArgs[i].ParameterType))
  57                                         return false;
  58                         }
  59                         return true;
  60                 }
  61
  62                 private static bool EqualSignatureTypes (Type x, Type y)
  63                 {
  64                         if (x.IsGenericParameter != y.IsGenericParameter)
  65                                 return false;
  66
  67                         if (x.IsGenericParameter)
  68                         {
  69                                 if (x.GenericParameterPosition != y.GenericParameterPosition)
  70                                         return false;
  71                         }
  72                         else
  73                         {
  74                                 if (!x.Equals (y))
  75                                         return false;
  76                         }
  77                         return true;
  78                 }
  79
  80                 public int GetHashCode (MethodInfo obj)
  81                 {
  82                         return obj.Name.GetHashCode () ^ obj.GetParameters ().Length; // everything else would be too cumbersome
  83                 }
  84         }
  85 }