Imported Upstream version 4.6.0.125

Former-commit-id: a2155e9bd80020e49e72e86c44da02a8ac0e57a4

mcs/class/referencesource/System.Xml/InternalApis/NDP_Common/inc/Win8Helpers.cs

@@ -0,0 +1,88 @@
+//------------------------------------------------------------------------------
+// <copyright file="Compilation.cs" company="Microsoft">
+//     Copyright (c) Microsoft Corporation.  All rights reserved.
+// </copyright>
+// <owner current="true" primary="true">[....]</owner>                                                                
+//------------------------------------------------------------------------------
+
+namespace Microsoft.Win32 {
+    using System;
+    using System.Diagnostics;
+    using System.Runtime.CompilerServices;
+    using System.Runtime.ConstrainedExecution;
+    using System.Runtime.InteropServices;
+    using System.Runtime.Versioning;
+
+    [System.Security.SuppressUnmanagedCodeSecurity]
+    internal static class UnsafeNativeMethods
+    {
+#if !FEATURE_CORECLR
+        // On CoreCLR this is not the way to determine if a process is a tailored application (which means APPX).
+        // On CoreCLR AppX is determined by a flag past to the host which is exposed by AppDomain.IsAppXProcess in mscorlib.
+        // The reason for this if-def is to ensure nobody takes a dependency on this on CoreCLR.
+        
+        internal const String KERNEL32 = "kernel32.dll";
+
+        // WinError.h codes:
+        internal const int ERROR_INSUFFICIENT_BUFFER     = 0x007A;
+        internal const int ERROR_NO_PACKAGE_IDENTITY     = 0x3d54;
+
+        // AppModel.h functions (Win8+)
+        [DllImport(KERNEL32, CharSet = CharSet.None, EntryPoint = "GetCurrentPackageId")]
+        [System.Security.SecurityCritical]
+        [return: MarshalAs(UnmanagedType.I4)]
+        private static extern Int32 _GetCurrentPackageId(
+            ref Int32 pBufferLength,
+            Byte[] pBuffer);
+
+        // Copied from Win32Native.cs
+        // Note - do NOT use this to call methods.  Use P/Invoke, which will
+        // do much better things w.r.t. marshaling, pinning memory, security 
+        // stuff, better interactions with thread aborts, etc.  This is used
+        // solely by DoesWin32MethodExist for avoiding try/catch EntryPointNotFoundException
+        // in scenarios where an OS Version check is insufficient
+        [DllImport(KERNEL32, CharSet=CharSet.Ansi, BestFitMapping=false, SetLastError=true, ExactSpelling=true)]
+        [ResourceExposure(ResourceScope.None)]
+        private static extern IntPtr GetProcAddress(IntPtr hModule, String methodName);
+
+        [DllImport(KERNEL32, CharSet=CharSet.Auto, BestFitMapping=false, SetLastError=true)]
+        [ReliabilityContract(Consistency.WillNotCorruptState, Cer.MayFail)]
+        [ResourceExposure(ResourceScope.Process)]  // Is your module side-by-side?
+        private static extern IntPtr GetModuleHandle(String moduleName);
+
+        [System.Security.SecurityCritical]  // auto-generated
+        private static bool DoesWin32MethodExist(String moduleName, String methodName)
+        {
+            // GetModuleHandle does not increment the module's ref count, so we don't need to call FreeLibrary.
+            IntPtr hModule = GetModuleHandle(moduleName);
+            if (hModule == IntPtr.Zero) {
+                Debug.Assert(hModule != IntPtr.Zero, "GetModuleHandle failed.  Dll isn't loaded?");
+                return false;
+            }
+            IntPtr functionPointer = GetProcAddress(hModule, methodName);
+            return (functionPointer != IntPtr.Zero);       
+        }
+
+        [System.Security.SecuritySafeCritical]
+        private static bool _IsPackagedProcess()
+        {
+            OperatingSystem os = Environment.OSVersion;
+            if(os.Platform == PlatformID.Win32NT && os.Version >= new Version(6,2,0,0) && DoesWin32MethodExist(KERNEL32, "GetCurrentPackageId"))
+            {
+                Int32 bufLen = 0;
+                // Will return ERROR_INSUFFICIENT_BUFFER when running within a packaged application,
+                // and will return ERROR_NO_PACKAGE_IDENTITY otherwise.
+                return _GetCurrentPackageId(ref bufLen, null) == ERROR_INSUFFICIENT_BUFFER;
+            }
+            else
+            {   // We must be running on a downlevel OS.
+                return false;
+            }
+        }
+
+        [System.Security.SecuritySafeCritical]
+        internal static Lazy<bool> IsPackagedProcess = new Lazy<bool>(() => _IsPackagedProcess());
+#endif //!FEATURE_CORECLR
+    }
+}
+