Imported Upstream version 4.6.0.125

Former-commit-id: a2155e9bd80020e49e72e86c44da02a8ac0e57a4

mcs/class/referencesource/System.Configuration/Microsoft/Win32/SafeNativeMemoryHandle.cs

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+//------------------------------------------------------------------------------
+// <copyright file="UnsafeNativeMethods.cs" company="Microsoft">
+//     Copyright (c) Microsoft Corporation.  All rights reserved.
+// </copyright>
+//------------------------------------------------------------------------------
+
+namespace Microsoft.Win32 {
+    using System.Runtime.InteropServices;
+    using System;
+    using System.Security.Permissions;
+    using Microsoft.Win32.SafeHandles;
+    using System.Configuration;
+
+    // Safehandle for memory handles
+    [System.Security.SuppressUnmanagedCodeSecurityAttribute()]
+    internal sealed class SafeNativeMemoryHandle : SafeHandleZeroOrMinusOneIsInvalid {
+        private bool _useLocalFree = false;
+        [SecurityPermission(SecurityAction.LinkDemand, UnmanagedCode = true)]
+        internal SafeNativeMemoryHandle()
+            : this(false) {
+        }
+
+        internal SafeNativeMemoryHandle(bool useLocalFree)
+            : base(true) {
+            _useLocalFree = useLocalFree;
+        }
+
+        [SecurityPermission(SecurityAction.LinkDemand, UnmanagedCode = true)]
+        internal SafeNativeMemoryHandle(IntPtr handle, bool ownsHandle)
+            : base(ownsHandle) {
+            SetHandle(handle);
+        }
+
+        internal void SetDataHandle(IntPtr handle) {
+            SetHandle(handle);
+        }
+
+        override protected bool ReleaseHandle() {
+            if (handle != IntPtr.Zero) {
+                if (_useLocalFree == true)
+                    UnsafeNativeMethods.LocalFree(handle);
+                else
+                    Marshal.FreeHGlobal(handle);
+                handle = IntPtr.Zero;
+                return true;
+            }
+            return false;
+        }
+    }
+
+
+}
+