InternalPermissions.cs source code in C# .NET

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Code:

/ 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / wpf / src / Shared / MS / Internal / Permissions / InternalPermissions.cs / 1305600 / InternalPermissions.cs

                            //---------------------------------------------------------------------------- 
//
// 
//    Copyright (C) Microsoft Corporation.  All rights reserved.
//  
//
// 
// Description: Internal Permissions. 
//                  These are classes for permissions that will be asserted/demanded internally.
//                  But will be granted in full-trust. 
//                  Only internal avalon code will assert these permissions.
//
//              Using them allows the following:
//                  We can have very specific targeted asserts. So for example instead of 
//                  a blanket assert for Unmanaged code instead we can have very granular permissiosn.
// 
//                  They are still available by default in full-trust. 
//
//                  Currently the only way to detect User-Initiated actions is for commands. 
//                  So by associating a custom permisison with a command we can very tightly scope
//                  the set of operations allowed.
//
// From MSDN: 
//
// When you inherit from CodeAccessPermission, you must also implement the IUnrestrictedPermission interface. 
// The following CodeAccessPermission members must be overridden: Copy, Intersect, IsSubsetOf, ToXml, FromXml, and Union. 
// You must also define a constructor that takes a PermissionState as its only parameter.
// You must apply the SerializableAttribute attribute to a class that inherits from CodeAccessPermission. 
//
// InternalParameterlessPermissionBase is a base class that requires derived classes to only support one
// PermissionState (Unrestricted) and to have no parameters/properties/state.  As above, derived classes must also be
// [Serializable] and have a public constructor that takes PermissionState. 
//
// History: 
//  02/28/05 : marka - Created 
//---------------------------------------------------------------------------
 
using System;
using System.Diagnostics;
using System.Text;
using System.Security; 
using System.Security.Permissions;
using System.Windows; 
 
#if WINDOWS_BASE
using MS.Internal.WindowsBase; 
#endif

namespace MS.Internal.Permissions
{ 
    //
    // derive all InternalPermissions from this. 
    // Provides default implementations of several overridable methods on CodeAccessPermission 
    //
    [FriendAccessAllowed] 
    [Serializable]
    internal abstract class InternalParameterlessPermissionBase : CodeAccessPermission, IUnrestrictedPermission
    {
       //----------------------------------------------------- 
       //
       //  Constructors 
       // 
       //-----------------------------------------------------
        #region Constructor 

        protected InternalParameterlessPermissionBase(PermissionState state)
        {
            Debug.Assert(GetType().IsSerializable); 

            switch (state) 
            { 
            case PermissionState.Unrestricted:
                break; 
            case PermissionState.None:
            default:
                throw new ArgumentException(SR.Get(SRID.InvalidPermissionStateValue, state), "state");
            } 
        }
 
        #endregion Constructor 

       //------------------------------------------------------ 
       //
       //  Interface Methods
       //
       //----------------------------------------------------- 
        #region Interface Methods
 
        public bool IsUnrestricted() 
        {
            return true; 
        }

        #endregion Interface Methods
 
       //------------------------------------------------------
       // 
       //  Public Methods 
       //
       //------------------------------------------------------ 

        #region Public Methods

        public override SecurityElement ToXml() 
        {
           SecurityElement element = new SecurityElement("IPermission"); 
           Type type = this.GetType(); 
           StringBuilder AssemblyName = new StringBuilder(type.Assembly.ToString());
           AssemblyName.Replace('\"', '\''); 
           element.AddAttribute("class", type.FullName + ", " + AssemblyName);
           element.AddAttribute("version", "1");
           return element;
        } 

        public override void FromXml( SecurityElement elem) 
        { 
            // from XML is easy - there is no state.
        } 

        public override IPermission Intersect(IPermission target)
        {
            if(null == target) 
            {
                return null; 
            } 

            if ( target.GetType() != this.GetType() ) 
            {
                throw new ArgumentException( SR.Get(SRID.InvalidPermissionType, this.GetType().FullName), "target");
            }
 
            // there is no state. The intersection of 2 permissions of the same type is the same permission.
            return this.Copy(); 
        } 

        public override bool IsSubsetOf(IPermission target) 
        {
            if(null == target)
            {
                return false; 
            }
 
            if ( target.GetType() != this.GetType() ) 
            {
                throw new ArgumentException( SR.Get(SRID.InvalidPermissionType, this.GetType().FullName), "target"); 
            }

            // there is no state. If you are the same type as me - you are a subset of me.
            return true; 
        }
 
        public override IPermission Union(IPermission target) 
        {
            if(null == target) 
            {
                return null;
            }
 
            if ( target.GetType() != this.GetType() )
            { 
                throw new ArgumentException( SR.Get(SRID.InvalidPermissionType, this.GetType().FullName), "target"); 
            }
 
            // there is no state. The union of 2 permissions of the same type is the same permission.
            return this.Copy();
        }
 
        #endregion Public Methods
    } 
} 


// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.
                        

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