internal static bool CheckAccessFromUserNameImp(Services.Packages.Package _object, string userName, string securityDescriptor)
        {
            if (!PackageSecureService.IsSecurableImp)
                return true;

            // Owner can do anything
            if (CheckUserRightsImp(userName, "Owner"))
                return true;

            // User could have constant rights on the class
            if (CheckUserRightsImp(userName, securityDescriptor + " " + typeof(Services.Packages.Package).FullName))
                return true;

            if (_object.Owner != null && _object.Owner.Name == userName)
                return true;

            PackageAccessControlListCollection acls = _object.GetACLs(userName);
            if (acls.Count == 0)
            {
                if (userName.ToLowerInvariant() != "everyone")
                    return CheckAccessFromUserNameImp(_object, "Everyone", securityDescriptor);
                else return false;
            }

            PackageAccessControlList acl = acls[0];

            PackageAccessControlEntryCollection entries = PackageAccessControlEntry.GetEntries(securityDescriptor.ToLowerInvariant(), acl);
            if (entries.Count == 0)
            {
                // Descriptor missing; Add-it
                PackageAccessControlEntry entry = new PackageAccessControlEntry();
                entry.Descriptor = securityDescriptor.ToLowerInvariant();
                entry.UserName = userName;
                entry.Allow = false;
                entry.ACL = acl;
                entry.Create();
                return false;
            }

            if (!entries[0].Allow)
            {
                if (userName.ToLowerInvariant() != "everyone")
                    return CheckAccessFromUserNameImp(_object, "Everyone", securityDescriptor);
                else return false;
            }

            return true;
        }
        internal static void ChangeAccessImp(Services.Packages.Package _object, string userName, string securityDescriptor, bool allow, string SessionToken)
        {
            // Check if user can do that
            ModelSession session = CheckSessionImp(SessionToken);

            if (CheckAccessImp(_object, SessionToken, "ChangeAccess"))
            {
                try
                {
                    PackageAccessControlListCollection acls = _object.GetACLs(userName);
                    PackageAccessControlList acl;

                    if (acls.Count == 0)
                    {
                        acl = new PackageAccessControlList();
                        acl.UserName = userName;
                        acl.Package = _object;
                        acl.Create();
                    }
                    else
                    {
                        acl = acls[0];
                    }

                    PackageAccessControlEntry entry = new PackageAccessControlEntry();
                    entry.Descriptor = securityDescriptor.ToLowerInvariant();
                    entry.UserName = userName;
                    entry.Allow = allow;
                    entry.ACL = acl;
                    entry.Create();

                    return;
                }
                catch
                {
                }
            }

            throw new UnauthorizedAccessException("Access Denied");
        }