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//------------------------------------------------------------------------------
// <copyright file="PnrpPermission.cs" company="Microsoft">
// Copyright (c) Microsoft Corporation. All rights reserved.
// </copyright>
//------------------------------------------------------------------------------
namespace System.Net.PeerToPeer
{
using System.Security;
using System.Security.Permissions;
using System.Globalization;
/// <remarks>
/// PnrpPermission atrribute
/// </remarks>
[AttributeUsage(AttributeTargets.Method | AttributeTargets.Constructor |
AttributeTargets.Class | AttributeTargets.Struct |
AttributeTargets.Assembly,
AllowMultiple = true, Inherited = false)]
[Serializable()]
public sealed class PnrpPermissionAttribute : CodeAccessSecurityAttribute
{
/// <summary>
/// Just call base constructor
/// </summary>
/// <param name="action"></param>
public PnrpPermissionAttribute(SecurityAction action) : base(action) { }
/// <summary>
/// As required by the SecurityAttribute class.
/// </summary>
/// <returns></returns>
public override IPermission CreatePermission() {
if (Unrestricted) {
return new PnrpPermission(PermissionState.Unrestricted);
}
else {
return new PnrpPermission(PermissionState.None);
}
}
}
/// <remarks>
/// Currently we only support two levels - Unrestrictred or none
/// </remarks>
[Serializable]
public sealed class PnrpPermission : CodeAccessPermission, IUnrestrictedPermission
{
private bool m_noRestriction;
internal static readonly PnrpPermission UnrestrictedPnrpPermission = new PnrpPermission(PermissionState.Unrestricted);
/// <summary>
/// <para>
/// Creates a new instance of the <see cref='System.Net.PeerToPeer.PnrpPermission'/>
/// class that passes all demands or that fails all demands.
/// </para>
/// </summary>
public PnrpPermission(PermissionState state)
{
m_noRestriction = (state == PermissionState.Unrestricted);
}
internal PnrpPermission(bool free)
{
m_noRestriction = free;
}
// IUnrestrictedPermission interface methods
/// <summary>
/// <para>
/// Checks the overall permission state of the object.
/// </para>
/// </summary>
public bool IsUnrestricted()
{
return m_noRestriction;
}
// IPermission interface methods
/// <summary>
/// <para>
/// Creates a copy of a <see cref='System.Net.PeerToPeer.PnrpPermission'/> instance.
/// </para>
/// </summary>
public override IPermission Copy()
{
return new PnrpPermission(m_noRestriction);
}
/// <summary>
/// <para>Returns the logical union between two <see cref='System.Net.PeerToPeer.PnrpPermission'/> instances.</para>
/// </summary>
public override IPermission Union(IPermission target)
{
// Pattern suggested by Security engine
if (target == null) {
return this.Copy();
}
PnrpPermission other = target as PnrpPermission;
if (other == null) {
throw new ArgumentException( SR.GetString(SR.PnrpPermission_CantUnionWithNonPnrpPermission), "target");
}
return new PnrpPermission(m_noRestriction || other.m_noRestriction);
}
/// <summary>
/// <para>Returns the logical intersection between two <see cref='System.Net.PeerToPeer.PnrpPermission'/> instances.</para>
/// </summary>
public override IPermission Intersect(IPermission target)
{
// Pattern suggested by Security engine
if (target == null) {
return null;
}
PnrpPermission other = target as PnrpPermission;
if (other == null) {
throw new ArgumentException(SR.GetString(SR.PnrpPermission_CantIntersectWithNonPnrpPermission), "target");
}
// return null if resulting permission is restricted and empty
// Hence, the only way for a bool permission will be.
if (this.m_noRestriction && other.m_noRestriction) {
return new PnrpPermission(true);
}
return null;
}
/// <summary>
/// <para>Compares two <see cref='System.Net.PeerToPeer.PnrpPermission'/> instances.</para>
/// </summary>
public override bool IsSubsetOf(IPermission target)
{
// Pattern suggested by Security engine
if (target == null) {
return m_noRestriction == false;
}
PnrpPermission other = target as PnrpPermission;
if (other == null) {
throw new ArgumentException(SR.GetString(SR.PnrpPermission_TargetNotAPnrpPermission), "target");
}
//Here is the matrix of result based on m_noRestriction for me and she
// me.noRestriction she.noRestriction me.isSubsetOf(she)
// 0 0 1
// 0 1 1
// 1 0 0
// 1 1 1
return (!m_noRestriction || other.m_noRestriction);
}
/// <summary>
/// Cinstrcy from a security element
/// </summary>
/// <param name="securityElement"></param>
public override void FromXml(SecurityElement e)
{
if (e == null) {
throw new ArgumentNullException(SR.GetString(SR.InvalidSecurityElem));
}
// SecurityElement must be a permission element
if (!e.Tag.Equals("IPermission")) {
throw new ArgumentException(SR.GetString(SR.InvalidSecurityElem), "securityElement");
}
string className = e.Attribute("class");
// SecurityElement must be a permission element for this type
if (className == null) {
throw new ArgumentException(SR.GetString(SR.InvalidSecurityElem), "securityElement");
}
if (className.IndexOf(this.GetType().FullName, StringComparison.Ordinal) < 0) {
throw new ArgumentException(SR.GetString(SR.InvalidSecurityElem), "securityElement");
}
string str = e.Attribute("Unrestricted");
m_noRestriction = (str != null ? (0 == string.Compare(str, "true", StringComparison.OrdinalIgnoreCase)) : false);
}
/// <summary>
/// Copyto a security element
/// </summary>
/// <returns></returns>
public override SecurityElement ToXml()
{
SecurityElement securityElement = new SecurityElement("IPermission");
securityElement.AddAttribute("class", this.GetType().FullName + ", " + this.GetType().Module.Assembly.FullName.Replace('\"', '\''));
securityElement.AddAttribute("version", "1");
if (m_noRestriction) {
securityElement.AddAttribute("Unrestricted", "true");
}
return securityElement;
}
} // class PnrpPermission
} // namespace System.Net.PeerToPeer
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