SafeRightsManagementQueryHandle.cs source code in C# .NET

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Code:

                         / DotNET / DotNET / 8.0 / untmp / WIN_WINDOWS / lh_tools_devdiv_wpf / Windows / wcp / Base / MS / Internal / Security / RightsManagement / SafeRightsManagementQueryHandle.cs / 1 / SafeRightsManagementQueryHandle.cs
                        

                        
                            //------------------------------------------------------------------------------ 
//
// 
//    Copyright (c) Microsoft Corporation.  All rights reserved.
//  
//
// Description: 
//  SafeRightsManagementQueryHandle class 
//
// History: 
//  10/12/2005: [....]:  Initial implementation.
//
//-----------------------------------------------------------------------------
 
using System;
using System.Runtime.InteropServices; 
using Microsoft.Win32.SafeHandles; 
using System.Security;
 
namespace MS.Internal.Security.RightsManagement
{
    [SecurityCritical(SecurityCriticalScope.Everything)]
    internal sealed class SafeRightsManagementQueryHandle : SafeHandle 
    {
        //Although it is not obvious this constructor is being called by the interop services 
        // it throws exceptions without it 
        private SafeRightsManagementQueryHandle()
            : base(IntPtr.Zero, true) 
        {
        }

        //  We have incompatibility between SafeHandle class hierarchy and the unmanaged 
        //  DRM SDK declarations. In the safe handle hierarchy it is assumed that the type
        //  of handle is the IntPtr (64 or 32 bit depending on the platform). In the unmanaged 
        //  SDK C++ unsigned long type is used, which is 32 bit regardless of the platform. 
        //  We have decided the safest thing would be to still use the SafeHandle classes
        //  and subclasses and cast variable back and force under assumption that IntPtr 
        //  is at least as big as unsigned long (in the managed code we generally use uint
        //  declaration for that)
        internal SafeRightsManagementQueryHandle(uint handle)
            : base((IntPtr)handle, true)  // "true" means "owns the handle" 
        {
        } 
 
        // base class expects us to override this method with the handle specific release code
        protected override bool ReleaseHandle() 
        {
            int z = 0;
            if (!IsInvalid)
            { 
                        // we can not use safe handle in the DrmClose... function
                        // as the SafeHandle implementation marks this instance as an invalid by the time 
                        // ReleaseHandle is called. After that marshalling code doesn't let the current instance 
                        // of the Safe*Handle sub-class to cross managed/unmanaged boundary.
                z = SafeNativeMethods.DRMCloseQueryHandle((uint)this.handle); 
        #if DEBUG
                    Errors.ThrowOnErrorCode(z);
        #endif
 
                // This member might be called twice(depending on the client app). In order to
                // prevent Unmanaged RM SDK from returning an error (Handle is already closed) 
                // we need to mark our handle as invalid after successful close call 
                base.SetHandle(IntPtr.Zero);
            } 

            return (z>=0);
        }
 

        // apparently there is no existing implementation that treats Zero and only Zero as an invalid value 
        // so we are sub-classing the base class and we need to override the IsInvalid property along with 
        // ReleaseHandle implementation
        public override bool IsInvalid 
        {
            get
            {
                return this.handle.Equals(IntPtr.Zero); 
            }
        } 
    } 
}

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

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