context: //
  // System.Security.Permissions.ReflectionPermission.cs
  //
  // Authors:
  //	Tim Coleman <tim@timcoleman.com>
  //	Sebastien Pouliot  <sebastien@ximian.com>
  //
  // Copyright (C) 2002, Tim Coleman
  // Portions (C) 2003 Motus Technologies Inc. (http://www.motus.com)
  // Copyright (C) 2004-2005 Novell, Inc (http://www.novell.com)
  //
  // Permission is hereby granted, free of charge, to any person obtaining
  // a copy of this software and associated documentation files (the
  // "Software"), to deal in the Software without restriction, including
  // without limitation the rights to use, copy, modify, merge, publish,
  // distribute, sublicense, and/or sell copies of the Software, and to
  // permit persons to whom the Software is furnished to do so, subject to
  // the following conditions:
  // 
  // The above copyright notice and this permission notice shall be
  // included in all copies or substantial portions of the Software.
  // 
  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  //
  
  using System.Globalization;
  using System.Runtime.InteropServices;
  
  namespace System.Security.Permissions {
  
  	[ComVisible (true)]
  	[Serializable]
  	public sealed class ReflectionPermission : CodeAccessPermission, IUnrestrictedPermission, IBuiltInPermission {
  
  		private const int version = 1;
  
  		ReflectionPermissionFlag flags;
  
  
  		public ReflectionPermission (PermissionState state)
  		{
  			if (CheckPermissionState (state, true) == PermissionState.Unrestricted)
  				flags = ReflectionPermissionFlag.AllFlags;
  			else
  				flags = ReflectionPermissionFlag.NoFlags;
  		}
  
  		public ReflectionPermission (ReflectionPermissionFlag flag)
  		{
  			// reuse validation by the Flags property
  			Flags = flag;
  		}
  
  
  		public ReflectionPermissionFlag Flags {
  			get { return flags; }
  			set {
  				const ReflectionPermissionFlag all_flags = ReflectionPermissionFlag.AllFlags | ReflectionPermissionFlag.RestrictedMemberAccess;
  
  				if ((value & all_flags) != value) {
  					string msg = String.Format (Locale.GetText ("Invalid flags {0}"), value);
  					throw new ArgumentException (msg, "ReflectionPermissionFlag");
  				}
  
  				flags = value;
  			}
  		}
  
  
  		public override IPermission Copy ()
  		{
  			return new ReflectionPermission (flags);
  		}
  
  		public override void FromXml (SecurityElement esd)
  		{
  			// General validation in CodeAccessPermission
  			CheckSecurityElement (esd, "esd", version, version);
  			// Note: we do not (yet) care about the return value 
  			// as we only accept version 1 (min/max values)
  
  			if (IsUnrestricted (esd)) {
  				flags = ReflectionPermissionFlag.AllFlags;
  			}
  			else {
  				flags = ReflectionPermissionFlag.NoFlags;
  				string xmlFlags = (esd.Attributes ["Flags"] as string);
  				if (xmlFlags.IndexOf ("MemberAccess") >= 0)
  					flags |= ReflectionPermissionFlag.MemberAccess;
  				if (xmlFlags.IndexOf ("ReflectionEmit") >= 0)
  					flags |= ReflectionPermissionFlag.ReflectionEmit;
  				if (xmlFlags.IndexOf ("TypeInformation") >= 0)
  					flags |= ReflectionPermissionFlag.TypeInformation;
  			}
  		}
  
  		public override IPermission Intersect (IPermission target)
  		{
  			ReflectionPermission rp = Cast (target);
  			if (rp == null)
  				return null;
  
  			if (IsUnrestricted ()) {
  				if (rp.Flags == ReflectionPermissionFlag.NoFlags)
  					return null;
  				else
  					return rp.Copy ();
  			}
  			if (rp.IsUnrestricted ()) {
  				if (flags == ReflectionPermissionFlag.NoFlags)
  					return null;
  				else
  					return Copy ();
  			}
  
  			ReflectionPermission p = (ReflectionPermission) rp.Copy ();
  			p.Flags &= flags;
  			return ((p.Flags == ReflectionPermissionFlag.NoFlags) ? null : p);
  		}
  
  		public override bool IsSubsetOf (IPermission target)
  		{
  			ReflectionPermission rp = Cast (target);
  			if (rp == null)
  				return (flags == ReflectionPermissionFlag.NoFlags);
  
  			if (IsUnrestricted ())
  				return rp.IsUnrestricted ();
  			else if (rp.IsUnrestricted ())
  				return true;
  
  			return ((flags & rp.Flags) == flags);
  		}
  
  		public bool IsUnrestricted ()
  		{
  			return (flags == ReflectionPermissionFlag.AllFlags);
  		}
  
  		public override SecurityElement ToXml ()
  		{
  			SecurityElement se = Element (version);
  			if (IsUnrestricted ()) {
  				se.AddAttribute ("Unrestricted", "true");
  			}
  			else {
  				if (flags == ReflectionPermissionFlag.NoFlags)
  					se.AddAttribute ("Flags", "NoFlags");
  				else if ((flags & ReflectionPermissionFlag.AllFlags) == ReflectionPermissionFlag.AllFlags)
  					se.AddAttribute ("Flags", "AllFlags");
  				else {
  					string xmlFlags = "";
  					if ((flags & ReflectionPermissionFlag.MemberAccess) == ReflectionPermissionFlag.MemberAccess)
  						xmlFlags = "MemberAccess";
  					if ((flags & ReflectionPermissionFlag.ReflectionEmit) == ReflectionPermissionFlag.ReflectionEmit) {
  						if (xmlFlags.Length > 0)
  							xmlFlags += ", ";
  						xmlFlags += "ReflectionEmit";
  					}
  					if ((flags & ReflectionPermissionFlag.TypeInformation) == ReflectionPermissionFlag.TypeInformation) {
  						if (xmlFlags.Length > 0)
  							xmlFlags += ", ";
  						xmlFlags += "TypeInformation";
  					}
  					se.AddAttribute ("Flags", xmlFlags);
  				}
  			}
  			return se;
  		}
  
  		public override IPermission Union (IPermission other)
  		{
  			ReflectionPermission rp = Cast (other);
  			if (other == null)
  				return Copy ();
  
  			if (IsUnrestricted () || rp.IsUnrestricted ())
  				return new ReflectionPermission (PermissionState.Unrestricted);
  
  			ReflectionPermission p = (ReflectionPermission) rp.Copy ();
  			p.Flags |= flags;
  			return p;
  		}
  
  		// IBuiltInPermission
  		int IBuiltInPermission.GetTokenIndex ()
  		{
  			return (int) BuiltInToken.Reflection;
  		}
  
  		// helpers
  
  		private ReflectionPermission Cast (IPermission target)
  		{
  			if (target == null)
  				return null;
  
  			ReflectionPermission rp = (target as ReflectionPermission);
  			if (rp == null) {
  
gt: 				ThrowInvalidPermission (target, typeof (ReflectionPermission));