Imported Upstream version 4.6.0.125

Former-commit-id: a2155e9bd80020e49e72e86c44da02a8ac0e57a4

mcs/class/referencesource/System/compmod/microsoft/win32/safehandles/SafeFileMappingHandle.cs

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+// ==++==
+// 
+//   Copyright (c) Microsoft Corporation.  All rights reserved.
+// 
+// ==--==
+/*============================================================
+**
+** Class:  SafeFileMappingHandle
+**
+** <EMAIL>Author: David Gutierrez ([....]) </EMAIL>
+**
+** A wrapper for handle to file mappings, returned by 
+** CreateFileMapping and OpenFileMapping.  Used for shared 
+** memory.
+**
+** 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 SafeFileMappingHandle : SafeHandleZeroOrMinusOneIsInvalid
+    { 
+        // Note that CreateFileMapping returns 0 on failure.
+
+        // Note that you can pass in -1 for the hFile parameter.
+        [SecurityPermission(SecurityAction.LinkDemand, UnmanagedCode=true)]
+        internal SafeFileMappingHandle() : base(true) {}
+             
+        [DllImport(ExternDll.Kernel32, ExactSpelling=true, SetLastError=true)]
+        [ResourceExposure(ResourceScope.None)]
+        [ReliabilityContract(Consistency.WillNotCorruptState, Cer.Success)]
+        private static extern bool CloseHandle(IntPtr handle);
+
+        override protected bool ReleaseHandle()
+        {
+            return CloseHandle(handle);
+        }
+    }
+}