mcs/class/System.ComponentModel.Composition/src/ComponentModel/Microsoft/Internal/ReflectionInvoke.cs

   1 #if !SILVERLIGHT && CLR40\r
   2 \r
   3 using System;\r
   4 using System.Reflection;\r
   5 using System.Security;\r
   6 using System.Security.Permissions;\r
   7 \r
   8 namespace Microsoft.Internal\r
   9 {\r
  10     internal static class ReflectionInvoke\r
  11     {\r
  12         private static readonly ReflectionPermission _memberAccess = new ReflectionPermission(ReflectionPermissionFlag.MemberAccess);\r
  13         private static readonly ReflectionPermission _restrictedMemberAccess = new ReflectionPermission(ReflectionPermissionFlag.RestrictedMemberAccess);\r
  14 \r
  15         public static object SafeCreateInstance(this Type type, params object[] arguments)\r
  16         {\r
  17             DemandMemberAccessIfNeeded(type);\r
  18 \r
  19             return Activator.CreateInstance(type, arguments);\r
  20         }\r
  21 \r
  22         public static object SafeInvoke(this ConstructorInfo constructor, params object[] arguments)\r
  23         {\r
  24             DemandMemberAccessIfNeeded(constructor);\r
  25 \r
  26             return constructor.Invoke(arguments);\r
  27         }\r
  28 \r
  29         public static object SafeInvoke(this MethodInfo method, object instance, params object[] arguments)\r
  30         {\r
  31             DemandMemberAccessIfNeeded(method);\r
  32 \r
  33             return method.Invoke(instance, arguments);\r
  34         }\r
  35 \r
  36         public static object SafeGetValue(this FieldInfo field, object instance)\r
  37         {\r
  38             DemandMemberAccessIfNeeded(field);\r
  39 \r
  40             return field.GetValue(instance);\r
  41         }\r
  42 \r
  43         public static void SafeSetValue(this FieldInfo field, object instance, object value)\r
  44         {\r
  45             DemandMemberAccessIfNeeded(field);\r
  46 \r
  47             field.SetValue(instance, value);\r
  48         }\r
  49 \r
  50         public static void DemandMemberAccessIfNeeded(MethodInfo method)\r
  51         {\r
  52             if (!method.IsVisible())\r
  53             {\r
  54                 DemandMemberAccess(method);\r
  55             }\r
  56         }\r
  57 \r
  58         private static void DemandMemberAccessIfNeeded(FieldInfo field)\r
  59         {\r
  60             if (!field.IsVisible())\r
  61             {\r
  62                 DemandMemberAccess(field);\r
  63             }\r
  64         }\r
  65 \r
  66         public static void DemandMemberAccessIfNeeded(Type type)\r
  67         {\r
  68             // Consult UnderlyingSystemType this is the type that Activator.CreateInstance creates            \r
  69             if (!type.UnderlyingSystemType.IsVisible)\r
  70             {\r
  71                 DemandMemberAccess(type);\r
  72             }\r
  73         }\r
  74 \r
  75         private static void DemandMemberAccessIfNeeded(ConstructorInfo constructor)\r
  76         {\r
  77             if (!constructor.IsVisible())\r
  78             {\r
  79                 DemandMemberAccess(constructor);\r
  80             }\r
  81         }\r
  82 \r
  83         private static void DemandMemberAccess(MemberInfo target)\r
  84         {\r
  85             try\r
  86             {\r
  87                 _memberAccess.Demand();\r
  88             }\r
  89             catch (SecurityException)\r
  90             {   // The caller doesn't have member access, but let's see whether they have access to\r
  91                 // members of assemblies with less or equal permissions (this mimics Reflection's behavior)\r
  92 \r
  93                 DemandRestrictedMemberAccess(target);\r
  94             }\r
  95         }\r
  96 \r
  97         private static void DemandRestrictedMemberAccess(MemberInfo target)\r
  98         {\r
  99             Assembly targetAssembly = target.Assembly();\r
 100 \r
 101             PermissionSet targetGrantSet = UnsafePermissionSet(targetAssembly);\r
 102             targetGrantSet.AddPermission(_restrictedMemberAccess);\r
 103             targetGrantSet.Demand();\r
 104         }\r
 105 \r
 106         [SecuritySafeCritical] // PermissionSet is [SecurityCritical]\r
 107         private static PermissionSet UnsafePermissionSet(Assembly assembly)\r
 108         {\r
 109             return assembly.PermissionSet;\r
 110         }\r
 111     }\r
 112 }\r
 113 \r
 114 #endif