PolicyStatement.cs :  » 2.6.4-mono-.net-core » System.Security » System » Security » Policy » C# / CSharp Open Source

//
// System.Security.Policy.PolicyStatement.cs
//
// Authors:
//  Dan Lewis (dihlewis@yahoo.co.uk)
//  Sebastien Pouliot  <sebastien@ximian.com>
//
// (C) 2002
// 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.Runtime.InteropServices;
using System.Security.Permissions;

namespace System.Security.Policy{

  [Serializable]
  [ComVisible (true)]
  public sealed class PolicyStatement : ISecurityEncodable, ISecurityPolicyEncodable {

    private PermissionSet perms;
    private PolicyStatementAttribute attrs;

    public PolicyStatement (PermissionSet permSet) :
      this (permSet, PolicyStatementAttribute.Nothing)
    {
    }

    public PolicyStatement (PermissionSet permSet, PolicyStatementAttribute attributes) 
    {
      if (permSet != null) {
        this.perms = permSet.Copy ();
        this.perms.SetReadOnly (true);
      }
      this.attrs = attributes;
    }
    
    public PermissionSet PermissionSet {
      get {
        if (perms == null) {
          perms = new PermissionSet (PermissionState.None);
          perms.SetReadOnly (true);
        }
        return perms;
      }
      set { perms = value; }
    }
    
    public PolicyStatementAttribute Attributes {
      get { return attrs; }
      set {
        // note: yes it's a flag but all possible values have a corresponding name
        switch (value) {
        case PolicyStatementAttribute.Nothing:
        case PolicyStatementAttribute.Exclusive:
        case PolicyStatementAttribute.LevelFinal:
        case PolicyStatementAttribute.All:
          attrs = value;
          break;
        default:
          string msg = Locale.GetText ("Invalid value for {0}.");
          throw new ArgumentException (String.Format (msg, "PolicyStatementAttribute"));
        }
      }
    }

    public string AttributeString {
      get {
        switch (attrs) {
        case PolicyStatementAttribute.Exclusive:
          return "Exclusive";
        case PolicyStatementAttribute.LevelFinal:
          return "LevelFinal";
        case PolicyStatementAttribute.All:
          return "Exclusive LevelFinal";
        default:
          return String.Empty;
        }
      }
    }

    public PolicyStatement Copy ()
    {
      return new PolicyStatement (perms, attrs);
    }

    // ISecurityEncodable

    public void FromXml (SecurityElement et)
    {
      FromXml (et, null);
    }

    public void FromXml (SecurityElement et, PolicyLevel level)
    {
      if (et == null)
        throw new ArgumentNullException ("et");
      if (et.Tag != "PolicyStatement")
        throw new ArgumentException (Locale.GetText ("Invalid tag."));


      string attributes = et.Attribute ("Attributes");
      if (attributes != null) {
        attrs = (PolicyStatementAttribute) Enum.Parse (
          typeof (PolicyStatementAttribute), attributes);
      }

      SecurityElement permissions = et.SearchForChildByTag ("PermissionSet");
      PermissionSet.FromXml (permissions);
    }
    
    public SecurityElement ToXml ()
    {
      return ToXml (null);
    }

    public SecurityElement ToXml (PolicyLevel level)
    {
      SecurityElement element = new SecurityElement ("PolicyStatement");
      element.AddAttribute ("version", "1");

      if (attrs != PolicyStatementAttribute.Nothing)
        element.AddAttribute ("Attributes", attrs.ToString ());
      
      element.AddChild (PermissionSet.ToXml ());

      return element;
    }

    [ComVisible (false)]
    public override bool Equals (object obj)
    {
      if (obj == null)
        return false;
      PolicyStatement ps = (obj as PolicyStatement);
      if (ps == null)
        return false;

      return (PermissionSet.Equals (obj) && (attrs == ps.attrs));
    }

    [ComVisible (false)]
    public override int GetHashCode ()
    {
      // return same hash code if two PolicyStatement are equals
      return (PermissionSet.GetHashCode () ^ (int) attrs);
    }

    internal static PolicyStatement Empty ()
    {
      return new PolicyStatement (new PermissionSet (PermissionState.None));
    }
  }
}