PowerShell-PSReadLine/PSReadLine/ConsoleLib.cs

/********************************************************************++
Copyright (c) Microsoft Corporation.  All rights reserved.
--********************************************************************/

using System;
using System.Text;

namespace Microsoft.PowerShell.Internal
{
    internal class VirtualTerminal : IConsole
    {
        // These two fields are used by PowerShellEditorServices to inject a
        // custom ReadKey implementation. This is not a public API, but it is
        // part of a private contract with that project.
        #pragma warning disable CS0649
        private static Func<bool, ConsoleKeyInfo> _readKeyOverride;
        #pragma warning restore CS0649

        private static Lazy<Func<bool, ConsoleKeyInfo>> _readKeyMethod = new Lazy<Func<bool, ConsoleKeyInfo>>(
            () => _readKeyOverride == null ? Console.ReadKey : _readKeyOverride);

        public int CursorLeft
        {
            get => Console.CursorLeft;
            set => Console.CursorLeft = value;
        }

        public int CursorTop
        {
            get => Console.CursorTop;
            set => Console.CursorTop = value;
        }

        // .NET doesn't implement this API, so we fake it with a commonly supported escape sequence.
        protected int _unixCursorSize = 25;
        public virtual int CursorSize
        {
            get => PlatformWindows.IsConsoleApiAvailable(input: false, output: true) ? Console.CursorSize : _unixCursorSize;
            set
            {
                if (PlatformWindows.IsConsoleApiAvailable(input: false, output: true))
                {
                    Console.CursorSize = value;
                }
                else
                {
                    _unixCursorSize = value;
                    // Solid blinking block or blinking vertical bar
                    Write(value > 50 ? "\x1b[2 q" : "\x1b[5 q");
                }
            }
        }

        public bool CursorVisible
        {
            get => Console.CursorVisible;
            set => Console.CursorVisible = value;
        }

        public int BufferWidth
        {
            get => Console.BufferWidth;
            set => Console.BufferWidth = value;
        }

        public int BufferHeight
        {
            get => Console.BufferHeight;
            set => Console.BufferHeight = value;
        }

        public int WindowWidth
        {
            get => Console.WindowWidth;
            set => Console.WindowWidth = value;
        }

        public int WindowHeight
        {
            get => Console.WindowHeight;
            set => Console.WindowHeight = value;
        }

        public int WindowTop
        {
            get => Console.WindowTop;
            set => Console.WindowTop = value;
        }

        public ConsoleColor BackgroundColor
        {
            get => Console.BackgroundColor;
            set => Console.BackgroundColor = value;
        }

        public ConsoleColor ForegroundColor
        {
            get => Console.ForegroundColor;
            set => Console.ForegroundColor = value;
        }

        public Encoding OutputEncoding
        {
            // Catch and ignore exceptions - if we can't change the encoding, output is
            // probably redirected, but it can also happen with the legacy console on Windows.
            get { try { return Console.OutputEncoding; } catch { return Encoding.Default; } }
            set { try { Console.OutputEncoding = value; } catch { } }
        }

        public ConsoleKeyInfo ReadKey()                  => _readKeyMethod.Value(true);
        public bool KeyAvailable                         => Console.KeyAvailable;
        public void SetWindowPosition(int left, int top) => Console.SetWindowPosition(left, top);
        public void SetCursorPosition(int left, int top) => Console.SetCursorPosition(left, top);
        public virtual void Write(string value)          => Console.Write(value);
        public virtual void WriteLine(string value)      => Console.WriteLine(value);
        public virtual void BlankRestOfLine()            => Console.Write("\x1b[K");
    }
}