//
// System.Net.DnsPermission.cs
//
// Authors:
// Lawrence Pit (loz@cable.a2000.nl)
// Sebastien Pouliot <sebastien@ximian.com>
//
// Copyright (C) 2004 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.Collections;
using System.Security;
using System.Security.Permissions;
namespace System.Net{
[Serializable]
public sealed class DnsPermission : CodeAccessPermission, IUnrestrictedPermission {
private const int version = 1;
// Fields
bool m_noRestriction;
// Constructors
public DnsPermission (PermissionState state)
: base ()
{
m_noRestriction = (state == PermissionState.Unrestricted);
}
// Methods
public override IPermission Copy ()
{
return new DnsPermission (m_noRestriction ? PermissionState.Unrestricted : PermissionState.None);
}
public override IPermission Intersect (IPermission target)
{
DnsPermission dp = Cast (target);
if (dp == null)
return null;
if (IsUnrestricted () && dp.IsUnrestricted ())
return new DnsPermission (PermissionState.Unrestricted);
return null;
}
public override bool IsSubsetOf (IPermission target)
{
DnsPermission dp = Cast (target);
if (dp == null)
return IsEmpty ();
return (dp.IsUnrestricted () || (m_noRestriction == dp.m_noRestriction));
}
public bool IsUnrestricted ()
{
return this.m_noRestriction;
}
public override SecurityElement ToXml ()
{
SecurityElement se = PermissionHelper.Element (typeof (DnsPermission), version);
if (m_noRestriction)
se.AddAttribute ("Unrestricted", "true");
return se;
}
public override void FromXml (SecurityElement securityElement)
{
PermissionHelper.CheckSecurityElement (securityElement, "securityElement", version, version);
// LAMESPEC: it says to throw an ArgumentNullException in this case
if (securityElement.Tag != "IPermission")
throw new ArgumentException ("securityElement");
this.m_noRestriction = PermissionHelper.IsUnrestricted (securityElement);
}
public override IPermission Union (IPermission target)
{
DnsPermission dp = Cast (target);
if (dp == null)
return Copy ();
if (IsUnrestricted () || dp.IsUnrestricted ())
return new DnsPermission (PermissionState.Unrestricted);
else
return new DnsPermission (PermissionState.None);
}
// Internal helpers methods
private bool IsEmpty ()
{
return !m_noRestriction;
}
private DnsPermission Cast (IPermission target)
{
if (target == null)
return null;
DnsPermission dp = (target as DnsPermission);
if (dp == null) {
PermissionHelper.ThrowInvalidPermission (target, typeof (DnsPermission));
}
return dp;
}
}
}
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