mcs/class/corlib/System.Security.Permissions/HostProtectionPermission.cs

   1 //
   2 // System.Security.Permissions.HostProtectionPermission.cs
   3 //
   4 // Author:
   5 //      Sebastien Pouliot  <sebastien@ximian.com>
   6 //
   7 // Copyright (C) 2004 Novell, Inc (http://www.novell.com)
   8 //
   9 // Permission is hereby granted, free of charge, to any person obtaining
  10 // a copy of this software and associated documentation files (the
  11 // "Software"), to deal in the Software without restriction, including
  12 // without limitation the rights to use, copy, modify, merge, publish,
  13 // distribute, sublicense, and/or sell copies of the Software, and to
  14 // permit persons to whom the Software is furnished to do so, subject to
  15 // the following conditions:
  16 //
  17 // The above copyright notice and this permission notice shall be
  18 // included in all copies or substantial portions of the Software.
  19 //
  20 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  21 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  22 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  23 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  24 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  25 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  26 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  27 //
  28
  29 #if NET_2_0
  30
  31 using System.Globalization;
  32
  33 namespace System.Security.Permissions {
  34
  35         [Serializable]
  36         internal sealed class HostProtectionPermission : CodeAccessPermission, IUnrestrictedPermission, IBuiltInPermission {
  37
  38                 private const int version = 1;
  39
  40                 private HostProtectionResource _resources;
  41
  42                 // constructors
  43
  44                 public HostProtectionPermission (PermissionState state)
  45                 {
  46                         if (CheckPermissionState (state, true) == PermissionState.Unrestricted)
  47                                 _resources = HostProtectionResource.All;
  48                         else
  49                                 _resources = HostProtectionResource.None;
  50                 }
  51
  52                 public HostProtectionPermission (HostProtectionResource resources)
  53                 {
  54                         // reuse validation by the Flags property
  55                         Resources = _resources;
  56                 }
  57
  58                 public HostProtectionResource Resources {
  59                         get { return _resources; }
  60                         set {
  61                                 if (!Enum.IsDefined (typeof (HostProtectionResource), value)) {
  62                                         string msg = String.Format (Locale.GetText ("Invalid enum {0}"), value);
  63                                         throw new ArgumentException (msg, "HostProtectionResource");
  64                                 }
  65                                 _resources = value;
  66                         }
  67                 }
  68
  69                 public override IPermission Copy ()
  70                 {
  71                         return new HostProtectionPermission (_resources);
  72                 }
  73
  74                 public override IPermission Intersect (IPermission target)
  75                 {
  76                         HostProtectionPermission hpp = Cast (target);
  77                         if (hpp == null)
  78                                 return null;
  79
  80                         if (this.IsUnrestricted () && hpp.IsUnrestricted ())
  81                                 return new HostProtectionPermission (PermissionState.Unrestricted);
  82                         if (this.IsUnrestricted ())
  83                                 return hpp.Copy ();
  84                         if (hpp.IsUnrestricted ())
  85                                 return this.Copy ();
  86                         return new HostProtectionPermission (_resources & hpp._resources);
  87                 }
  88
  89                 public override IPermission Union (IPermission target)
  90                 {
  91                         HostProtectionPermission hpp = Cast (target);
  92                         if (hpp == null)
  93                                 return this.Copy ();
  94
  95                         if (this.IsUnrestricted () || hpp.IsUnrestricted ())
  96                                 return new HostProtectionPermission (PermissionState.Unrestricted);
  97
  98                         return new HostProtectionPermission (_resources | hpp._resources);
  99                 }
 100
 101                 public override bool IsSubsetOf (IPermission target)
 102                 {
 103                         HostProtectionPermission hpp = Cast (target);
 104                         if (hpp == null)
 105                                 return (_resources == HostProtectionResource.None);
 106
 107                         if (hpp.IsUnrestricted ())
 108                                 return true;
 109                         if (this.IsUnrestricted ())
 110                                 return false;
 111
 112                         return ((_resources & ~hpp._resources) == 0);
 113                 }
 114
 115                 public override void FromXml (SecurityElement e)
 116                 {
 117                         // General validation in CodeAccessPermission
 118                         CheckSecurityElement (e, "e", version, version);
 119                         // Note: we do not (yet) care about the return value
 120                         // as we only accept version 1 (min/max values)
 121
 122                         _resources = (HostProtectionResource) Enum.Parse (
 123                                 typeof (HostProtectionResource), e.Attribute ("Resources"));
 124                 }
 125
 126                 public override SecurityElement ToXml ()
 127                 {
 128                         SecurityElement e = Element (version);
 129                         e.AddAttribute ("Resources", _resources.ToString ());
 130                         return e;
 131                 }
 132
 133                 // IUnrestrictedPermission
 134                 public bool IsUnrestricted ()
 135                 {
 136                         return (_resources == HostProtectionResource.All);
 137                 }
 138
 139                 // IBuiltInPermission
 140                 int IBuiltInPermission.GetTokenIndex ()
 141                 {
 142                         return (int) BuiltInToken.HostProtection;
 143                 }
 144
 145                 // helpers
 146
 147                 private HostProtectionPermission Cast (IPermission target)
 148                 {
 149                         if (target == null)
 150                                 return null;
 151
 152                         HostProtectionPermission hpp = (target as HostProtectionPermission);
 153                         if (hpp == null) {
 154                                 ThrowInvalidPermission (target, typeof (HostProtectionPermission));
 155                         }
 156
 157                         return hpp;
 158                 }
 159         }
 160 }
 161
 162 #endif