HGlobalSafeHandle.cs source code in C# .NET

Source code for the .NET framework in C#

                        

Code:

/ 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / cdf / src / WCF / infocard / common / managed / HGlobalSafeHandle.cs / 1305376 / HGlobalSafeHandle.cs

                            //------------------------------------------------------------------------------ 
// Copyright (c) Microsoft Corporation.  All rights reserved.
//-----------------------------------------------------------------------------
namespace Microsoft.InfoCards
{ 
    using System;
    using System.Runtime.InteropServices; 
    using Microsoft.InfoCards.Diagnostics; 
    using System.Runtime.CompilerServices;
    using System.Runtime.ConstrainedExecution; 
    using System.Security;
    using IDT=Microsoft.InfoCards.Diagnostics.InfoCardTrace;

 

    // 
    // Summary: 
    // Provides a wrapper over HGlobal alloc'd memory guaranteeing that the
    // contents will be released in the presence of rude app domain and thread aborts. 
    //
    internal class HGlobalSafeHandle : SafeHandle
    {
 
        public static HGlobalSafeHandle Construct()
        { 
            return new HGlobalSafeHandle(); 
        }
        public static HGlobalSafeHandle Construct( string managedString ) 
        {
            IDT.DebugAssert( !String.IsNullOrEmpty( managedString) , "null string" );

            int bytes = (managedString.Length + 1) * 2; 
            return new HGlobalSafeHandle( Marshal.StringToHGlobalUni( managedString ), bytes );
 
        } 

        public static HGlobalSafeHandle Construct( int bytes ) 
        {
            IDT.DebugAssert( bytes > 0, "attempt to allocate a handle with <= 0 bytes" );
            return new HGlobalSafeHandle( Marshal.AllocHGlobal( bytes ), bytes );
 
        }
 
        [SuppressUnmanagedCodeSecurity] 
        [ReliabilityContract(Consistency.WillNotCorruptState, Cer.Success)]
        [DllImport("Kernel32.dll", EntryPoint="RtlZeroMemory", SetLastError=false)] 
        public static extern void ZeroMemory( IntPtr dest, Int32 size );

        //
        // The number of bytes allocated. 
        //
        private int m_bytes; 
        [ReliabilityContract( Consistency.WillNotCorruptState, Cer.Success ) ] 
        private HGlobalSafeHandle( IntPtr toManage, int length ) : base( IntPtr.Zero, true )
        { 
            m_bytes = length;
            SetHandle( toManage );
        }
 
        private HGlobalSafeHandle() : base( IntPtr.Zero, true ) {}
 
        public override bool IsInvalid 
        {
            get 
            {
                return ( IntPtr.Zero == base.handle );
            }
        } 

 
        // 
        // Summary:
        // Zero the string contents and release the handle 
        //
        protected override bool ReleaseHandle()
        {
 
            IDT.DebugAssert( !IsInvalid, "handle is invalid in release handle" );
            IDT.DebugAssert( 0 != m_bytes, "invalid size" ); 
            ZeroMemory( base.handle, m_bytes ); 

            Marshal.FreeHGlobal( base.handle ); 
            return true;
        }

 
    }
} 

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
                        

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