// ==++==
// 
//   Copyright (c) Microsoft Corporation.  All rights reserved.
// 
// ==--==
/*============================================================
**
** Class:  SafeLibraryHandle 
**
** <EMAIL>Author: David Gutierrez (Microsoft) </EMAIL>
**
** A wrapper for a library handles
**
** Date:  July 8, 2002
** 
===========================================================*/

using System;
using System.Security;
using System.Security.Permissions;
using System.Runtime.InteropServices;
using System.Runtime.CompilerServices;
using Microsoft.Win32;
using Microsoft.Win32.SafeHandles;
using System.Runtime.ConstrainedExecution;
using System.Runtime.Versioning;

namespace Microsoft.Win32.SafeHandles {
    [HostProtectionAttribute(MayLeakOnAbort = true)]
    [SuppressUnmanagedCodeSecurityAttribute]
    internal sealed class SafeLibraryHandle : SafeHandleZeroOrMinusOneIsInvalid
    {
        // Note that LoadLibraryEx returns 0 on failure

        internal SafeLibraryHandle() : base(true) {}
        
        [DllImport(ExternDll.Kernel32, CharSet=System.Runtime.InteropServices.CharSet.Unicode, SetLastError=true)]
        [ResourceExposure(ResourceScope.Machine)]
        internal static extern SafeLibraryHandle LoadLibraryEx(string libFilename, IntPtr reserved, int flags);        
                
        [DllImport(ExternDll.Kernel32, CharSet=System.Runtime.InteropServices.CharSet.Unicode)]
        [ResourceExposure(ResourceScope.None)]
#if !FEATURE_WINDOWSPHONE
        [ReliabilityContract(Consistency.WillNotCorruptState, Cer.Success)]
#endif // !FEATURE_WINDOWSPHONE
        private static extern bool FreeLibrary(IntPtr hModule);     

        override protected bool ReleaseHandle()
        {
            return FreeLibrary(handle);
        }

    }
}