SafeMILHandle.cs source code in C# .NET

                        Code:
                         / Dotnetfx_Vista_SP2 / Dotnetfx_Vista_SP2 / 8.0.50727.4016 / DEVDIV / depot / DevDiv / releases / Orcas / QFE / wpf / src / Core / CSharp / System / Windows / Media / SafeMILHandle.cs / 1 / SafeMILHandle.cs
                        
                        
                            //---------------------------------------------------------------------------- 
//
// 
//    Copyright (C) Microsoft Corporation.  All rights reserved.
//  
//
// 
// Description: 
//      A safe way to deal with unmanaged MIL interface pointers.
//--------------------------------------------------------------------------- 

using System;
using System.IO;
using System.Security; 
using System.Security.Permissions;
using System.Collections; 
using System.Reflection; 
using MS.Internal;
using MS.Win32; 
using System.Diagnostics;
using System.Windows.Media;
using System.Runtime;
using System.Runtime.InteropServices; 
using System.Runtime.CompilerServices;
using Microsoft.Win32.SafeHandles; 
using Microsoft.Internal; 

using UnsafeNativeMethods=MS.Win32.PresentationCore.UnsafeNativeMethods; 

namespace System.Windows.Media
{
    internal class SafeMILHandle : SafeHandleZeroOrMinusOneIsInvalid 
    {
        ///  
        /// Use this constructor if the handle isn't ready yet and later 
        /// set the handle with SetHandle. SafeMILHandle owns the release
        /// of the handle. 
        /// 
        /// 
        ///    Critical: This derives from a class that has a link demand and inheritance demand
        ///    TreatAsSafe: Ok to call constructor 
        ///  
        [SecurityCritical,SecurityTreatAsSafe] 
        internal SafeMILHandle() : base(true) 
        {
        } 

        /// 
        /// Use this constructor if the handle exists at construction time.
        /// SafeMILHandle owns the release of the parameter. 
        /// 
        ///  
        ///    Critical: This code calls UpdateEstimatedSize. 
        ///                 It is used to keep memory around
        ///   
        [SecurityCritical]
        internal SafeMILHandle(IntPtr handle, long estimatedSize) : base(true)
        {
            SetHandle(handle); 

            // 
            // Hint the GC at the size of the unmanaged memory associated with 
            // this object.  We release pressure in the finalizer.
            // 

            UpdateEstimatedSize(estimatedSize);
        }
 
        /// 
        /// Change our size to the new size specified 
        ///  
        /// 
        ///    Critical: This code calls into AddMemoryPressure and RemoveMemoryPressure 
        ///                 both of which have link demands. It is used to keep memory around
        ///  
        [SecurityCritical]
        internal void UpdateEstimatedSize(long estimatedSize) 
        {
            if (_gcPressure > 0) 
            { 
                MemoryPressure.Remove(_gcPressure);
            } 

            _gcPressure = estimatedSize;

            if (_gcPressure > 0) 
            {
                MemoryPressure.Add(_gcPressure); 
            } 
        }
 
        /// 
        /// Critical - calls unmanaged code, not treat as safe because you must
        ///            validate that handle is a valid COM object.
        ///  
        [SecurityCritical]
        protected override bool ReleaseHandle() 
        { 
            UnsafeNativeMethods.MILUnknown.ReleaseInterface(ref handle);
 
            //
            // We've released the unmangaed memory, so remove associated
            // GC pressure.
            // 

            UpdateEstimatedSize(0); 
 
            return true;
        } 


        //
        // Estimated size in bytes of the unmanaged memory we are holding onto 
        //
 
        private long _gcPressure; 
    }
} 


// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.
//---------------------------------------------------------------------------- 
//
// 
//    Copyright (C) Microsoft Corporation.  All rights reserved.
//  
//
// 
// Description: 
//      A safe way to deal with unmanaged MIL interface pointers.
//--------------------------------------------------------------------------- 

using System;
using System.IO;
using System.Security; 
using System.Security.Permissions;
using System.Collections; 
using System.Reflection; 
using MS.Internal;
using MS.Win32; 
using System.Diagnostics;
using System.Windows.Media;
using System.Runtime;
using System.Runtime.InteropServices; 
using System.Runtime.CompilerServices;
using Microsoft.Win32.SafeHandles; 
using Microsoft.Internal; 

using UnsafeNativeMethods=MS.Win32.PresentationCore.UnsafeNativeMethods; 

namespace System.Windows.Media
{
    internal class SafeMILHandle : SafeHandleZeroOrMinusOneIsInvalid 
    {
        ///  
        /// Use this constructor if the handle isn't ready yet and later 
        /// set the handle with SetHandle. SafeMILHandle owns the release
        /// of the handle. 
        /// 
        /// 
        ///    Critical: This derives from a class that has a link demand and inheritance demand
        ///    TreatAsSafe: Ok to call constructor 
        ///  
        [SecurityCritical,SecurityTreatAsSafe] 
        internal SafeMILHandle() : base(true) 
        {
        } 

        /// 
        /// Use this constructor if the handle exists at construction time.
        /// SafeMILHandle owns the release of the parameter. 
        /// 
        ///  
        ///    Critical: This code calls UpdateEstimatedSize. 
        ///                 It is used to keep memory around
        ///   
        [SecurityCritical]
        internal SafeMILHandle(IntPtr handle, long estimatedSize) : base(true)
        {
            SetHandle(handle); 

            // 
            // Hint the GC at the size of the unmanaged memory associated with 
            // this object.  We release pressure in the finalizer.
            // 

            UpdateEstimatedSize(estimatedSize);
        }
 
        /// 
        /// Change our size to the new size specified 
        ///  
        /// 
        ///    Critical: This code calls into AddMemoryPressure and RemoveMemoryPressure 
        ///                 both of which have link demands. It is used to keep memory around
        ///  
        [SecurityCritical]
        internal void UpdateEstimatedSize(long estimatedSize) 
        {
            if (_gcPressure > 0) 
            { 
                MemoryPressure.Remove(_gcPressure);
            } 

            _gcPressure = estimatedSize;

            if (_gcPressure > 0) 
            {
                MemoryPressure.Add(_gcPressure); 
            } 
        }
 
        /// 
        /// Critical - calls unmanaged code, not treat as safe because you must
        ///            validate that handle is a valid COM object.
        ///  
        [SecurityCritical]
        protected override bool ReleaseHandle() 
        { 
            UnsafeNativeMethods.MILUnknown.ReleaseInterface(ref handle);
 
            //
            // We've released the unmangaed memory, so remove associated
            // GC pressure.
            // 

            UpdateEstimatedSize(0); 
 
            return true;
        } 


        //
        // Estimated size in bytes of the unmanaged memory we are holding onto 
        //
 
        private long _gcPressure; 
    }
} 


// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.
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SafeMILHandle.cs source code in C# .NET

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