System.Security.SecurityManager.SecurityManager.CheckPermissionSet C# (CSharp) Method

		internal static IPermission CheckPermissionSet (AppDomain ad, PermissionSet ps)
		{
			if ((ps == null) || ps.IsEmpty ())
				return null;

			PermissionSet granted = ad.GrantedPermissionSet;
			if (granted == null)
				return null;
#if NET_2_0
			if (granted.IsUnrestricted ())
				return null;
#else
			if ((granted.Count == 0) && granted.IsUnrestricted ())
				return null;
#endif
			if (ps.IsUnrestricted ())
				return new SecurityPermission (SecurityPermissionFlag.NoFlags);

			foreach (IPermission p in ps) {
				if (p is CodeAccessPermission) {
					CodeAccessPermission grant = (CodeAccessPermission) granted.GetPermission (p.GetType ());
					if (grant == null) {
						if (!granted.IsUnrestricted () || !(p is IUnrestrictedPermission)) {
							if (!p.IsSubsetOf (null))
								return p;
						}
					} else if (!p.IsSubsetOf (grant)) {
						return p;
					}
				} else {
					// but non-CAS will throw on failure...
					try {
						p.Demand ();
					}
					catch (SecurityException) {
						// ... so we catch
						return p;
					}
				}
			}
			return null;
		}