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

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