From ee4565066097992ebb36d5b1397c92d517e315a7 Mon Sep 17 00:00:00 2001
From: Steve Lee <slee@microsoft.com>
Date: Wed, 31 May 2017 10:26:41 -0700
Subject: [PATCH] Enable PSReadline to work on NanoServer (#3815)

NanoServer is missing some console APIs that PSReadline uses which causes PSReadline to not be usable on NanoServer docker images.

For the missing font/display APIs, the fix is to assume all characters use 1 cell which is not always correct for some languages.

For the missing keymap APIs - there is no workaround in this change and a small number of key bindings don't work, there is an open issue to track those.

Fixes #3463
---
 .../ConsoleKeyChordConverter.cs               |  6 +--
 .../ConsoleLib.cs                             | 47 +++++++++++++++----
 2 files changed, 42 insertions(+), 11 deletions(-)

diff --git a/src/Microsoft.PowerShell.PSReadLine/ConsoleKeyChordConverter.cs b/src/Microsoft.PowerShell.PSReadLine/ConsoleKeyChordConverter.cs
index 64de462c6..6abaa815e 100644
--- a/src/Microsoft.PowerShell.PSReadLine/ConsoleKeyChordConverter.cs
+++ b/src/Microsoft.PowerShell.PSReadLine/ConsoleKeyChordConverter.cs
@@ -1,4 +1,4 @@
-/********************************************************************++
+/********************************************************************++
 Copyright (c) Microsoft Corporation.  All rights reserved.
 --********************************************************************/
 
@@ -231,7 +231,6 @@ namespace Microsoft.PowerShell
             return valid;
         }
 
-#if UNIX
         // this is borrowed from the CoreFX internal System.IO.StdInReader class
         // https://github.com/dotnet/corefx/blob/5b2ae6aa485773cd5569f56f446698633c9ad945/src/System.Console/src/System/IO/StdInReader.cs#L222
         private static ConsoleKey GetKeyFromCharValue(char x, out bool isShift, out bool isCtrl)
@@ -303,7 +302,8 @@ namespace Microsoft.PowerShell
 
             return default(ConsoleKey);
         }
-#else
+
+#if !UNIX
         internal static char GetCharFromConsoleKey(ConsoleKey key, ConsoleModifiers modifiers)
         {
             // default for unprintables and unhandled
diff --git a/src/Microsoft.PowerShell.PSReadLine/ConsoleLib.cs b/src/Microsoft.PowerShell.PSReadLine/ConsoleLib.cs
index 01090bae3..98b9eb665 100644
--- a/src/Microsoft.PowerShell.PSReadLine/ConsoleLib.cs
+++ b/src/Microsoft.PowerShell.PSReadLine/ConsoleLib.cs
@@ -1,4 +1,4 @@
-/********************************************************************++
+/********************************************************************++
 Copyright (c) Microsoft Corporation.  All rights reserved.
 --********************************************************************/
 
@@ -370,6 +370,23 @@ namespace Microsoft.PowerShell.Internal
 
     internal static class ConsoleKeyInfoExtension
     {
+#if !UNIX
+        private static bool _toUnicodeApiAvailable = true;
+
+        static ConsoleKeyInfoExtension()
+        {
+            try
+            {
+                var chars = new char[2];
+                NativeMethods.ToUnicode(13, 28, null, chars, chars.Length, 0);
+            }
+            catch (System.EntryPointNotFoundException)
+            {
+                _toUnicodeApiAvailable = false;  // api not available on NanoServer
+            }
+        }
+#endif
+
         public static string ToGestureString(this ConsoleKeyInfo key)
         {
             var mods = key.Modifiers;
@@ -386,13 +403,16 @@ namespace Microsoft.PowerShell.Internal
                 sb.Append("Alt");
             }
 
-#if UNIX
             char c = key.KeyChar;
-#else
-            // Windows cannot use KeyChar as some chords (like Ctrl+[) show up as control characters.
-            char c = ConsoleKeyChordConverter.GetCharFromConsoleKey(key.Key,
-                (mods & ConsoleModifiers.Shift) != 0 ? ConsoleModifiers.Shift : 0);
+#if !UNIX
+            if (_toUnicodeApiAvailable)
+            {
+                // Windows cannot use KeyChar as some chords (like Ctrl+[) show up as control characters.
+                c = ConsoleKeyChordConverter.GetCharFromConsoleKey(key.Key,
+                    (mods & ConsoleModifiers.Shift) != 0 ? ConsoleModifiers.Shift : 0);
+            }
 #endif
+
             if (char.IsControl(c) || char.IsWhiteSpace(c))
             {
                 if (key.Modifiers.HasFlag(ConsoleModifiers.Shift))
@@ -426,6 +446,7 @@ namespace Microsoft.PowerShell.Internal
         private bool _istmInitialized = false;
         private TEXTMETRIC _tm = new TEXTMETRIC();
         private bool _trueTypeInUse = false;
+        private static bool _getCurrentConsoleFontExApiAvailable = true;
 
         private readonly Lazy<SafeFileHandle> _outputHandle = new Lazy<SafeFileHandle>(() =>
         {
@@ -691,7 +712,18 @@ namespace Microsoft.PowerShell.Internal
 
             CONSOLE_FONT_INFO_EX fontInfo = new CONSOLE_FONT_INFO_EX();
             fontInfo.cbSize = Marshal.SizeOf(fontInfo);
-            bool result = NativeMethods.GetCurrentConsoleFontEx(consoleHandle.DangerousGetHandle(), false, ref fontInfo);
+            bool result = true;
+            if (_getCurrentConsoleFontExApiAvailable)
+            {
+                try
+                {
+                    result = NativeMethods.GetCurrentConsoleFontEx(consoleHandle.DangerousGetHandle(), false, ref fontInfo);
+                }
+                catch (System.EntryPointNotFoundException)
+                {
+                    _getCurrentConsoleFontExApiAvailable = false;  // api not available on NanoServer
+                }
+            }
 
             if (result == false)
             {
@@ -865,7 +897,6 @@ namespace Microsoft.PowerShell.Internal
             CONSOLE_FONT_INFO_EX fontInfo = ConhostConsole.GetConsoleFontInfo(consoleHandle);
             int fontType = fontInfo.FontFamily & NativeMethods.FontTypeMask;
             _trueTypeInUse = (fontType & NativeMethods.TrueTypeFont) == NativeMethods.TrueTypeFont;
-
         }
 
         public void EndRender()