Initial Commit

Shared/KeyboardMouse/InputReader.cs

@@ -0,0 +1,166 @@
+using Microsoft.Extensions.Logging;
+
+namespace Barcode.Host.Shared.KeyboardMouse;
+
+public class InputReader : IDisposable
+{
+    private readonly ILogger<InputReader> _Logger;
+    private const int _BufferLength = 24;
+
+    private static readonly int _PiOffset;
+
+    private readonly byte[] _Buffer = new byte[_BufferLength];
+
+    private FileStream? _Stream;
+    private bool _Disposing;
+
+    public delegate void RaiseKeyPress(KeyPressEvent e);
+
+    public delegate void RaiseMouseMove(MouseMoveEvent e);
+
+    public event RaiseKeyPress? OnKeyPress;
+
+    public event RaiseMouseMove? OnMouseMove;
+
+    public string Path { get; }
+
+    public bool Faulted { get; private set; }
+
+    static InputReader()
+    {
+        if (RunningOnRaspberryPi())
+        {
+            _PiOffset = -8;
+        }
+    }
+
+    public InputReader(
+        string path,
+        ILogger<InputReader> logger)
+    {
+        _Logger = logger;
+
+        Path = path;
+
+        try
+        {
+            _Stream = new FileStream(path, FileMode.Open, FileAccess.Read, FileShare.ReadWrite);
+        }
+        catch (UnauthorizedAccessException ex)
+        {
+            _Logger.LogError(ex, "Current user doesn't have permissions to access input data. Add user to input group to correct this error");
+            Faulted = true;
+        }
+        catch (IOException ex)
+        {
+            _Logger.LogWarning(ex, $"Error occurred while trying to build stream for {path}");
+            Faulted = true;
+        }
+
+        _ = Task.Run(Run);
+    }
+
+    private void Run()
+    {
+        while (true)
+        {
+            if (_Disposing)
+                break;
+
+            try
+            {
+                if (!Faulted && _Stream is not null)
+                {
+                    _ = _Stream.Read(_Buffer, 0, _BufferLength);
+                }
+            }
+            catch (IOException ex)
+            {
+                _Logger.LogInformation(ex, $"Error occured while trying to read from the stream for {Path}");
+                Faulted = true;
+            }
+
+            EventType type = GetEventType();
+            short code = GetCode();
+            int value = GetValue();
+
+            switch (type)
+            {
+                case EventType.EV_KEY:
+                    HandleKeyPressEvent(code, value);
+                    break;
+                case EventType.EV_REL:
+                    MouseAxis axis = (MouseAxis)code;
+                    MouseMoveEvent e = new(axis, value);
+                    OnMouseMove?.Invoke(e);
+                    break;
+            }
+        }
+    }
+
+    private int GetValue()
+    {
+        byte[] valueBits = new[]
+        {
+            _Buffer[20 + _PiOffset],
+            _Buffer[21 + _PiOffset],
+            _Buffer[22 + _PiOffset],
+            _Buffer[23 + _PiOffset]
+        };
+
+        int value = BitConverter.ToInt32(valueBits, 0);
+
+        return value;
+    }
+
+    private short GetCode()
+    {
+        byte[] codeBits = new[]
+        {
+            _Buffer[18 + _PiOffset],
+            _Buffer[19 + _PiOffset]
+        };
+
+        short code = BitConverter.ToInt16(codeBits, 0);
+
+        return code;
+    }
+
+    private EventType GetEventType()
+    {
+        byte[] typeBits = new[]
+        {
+            _Buffer[16 + _PiOffset],
+            _Buffer[17 + _PiOffset]
+        };
+
+        short type = BitConverter.ToInt16(typeBits, 0);
+
+        EventType eventType = (EventType)type;
+
+        return eventType;
+    }
+
+    private void HandleKeyPressEvent(short code, int value)
+    {
+        EventCode c = (EventCode)code;
+        KeyState s = (KeyState)value;
+        KeyPressEvent e = new(c, s);
+        OnKeyPress?.Invoke(e);
+    }
+
+    public void Dispose()
+    {
+        _Disposing = true;
+        _Stream?.Dispose();
+        _Stream = null;
+    }
+
+    private static bool RunningOnRaspberryPi()
+    {
+        string path = "/proc/cpuinfo";
+        string[] text = File.ReadAllLines(path);
+        bool runningOnPi = text.Any(l => l.Contains("Raspberry Pi"));
+        return runningOnPi;
+    }
+}