Implement recorder PoC (#6)

2026-04-07 14:27:46 +09:00
parent e3d2ff6c77
commit d486cbb4d9
14 changed files with 996 additions and 0 deletions
--- a/src/Recordingtest.Recorder/LowLevelHook.cs
+++ b/src/Recordingtest.Recorder/LowLevelHook.cs
@@ -0,0 +1,133 @@
+using System;
+using System.Threading;
+using System.Threading.Channels;
+
+namespace Recordingtest.Recorder;
+
+public sealed record RawEvent(long TimestampMs, string Kind, int X, int Y, uint Code, int WheelDelta);
+
+/// <summary>
+/// Installs WH_KEYBOARD_LL and WH_MOUSE_LL hooks on a dedicated thread with its own message loop.
+/// Pushes RawEvent into a Channel for the main loop to consume.
+/// </summary>
+public sealed class LowLevelHook : IDisposable
+{
+    private readonly Channel<RawEvent> _channel;
+    private Thread? _thread;
+    private IntPtr _kbHook = IntPtr.Zero;
+    private IntPtr _mouseHook = IntPtr.Zero;
+    private NativeMethods.HookProc? _kbProc;
+    private NativeMethods.HookProc? _mouseProc;
+    private uint _threadId;
+    private volatile bool _running;
+
+    public LowLevelHook(Channel<RawEvent> channel)
+    {
+        _channel = channel;
+    }
+
+    public ChannelReader<RawEvent> Reader => _channel.Reader;
+
+    public void Start()
+    {
+        if (_running) return;
+        _running = true;
+        var ready = new ManualResetEventSlim(false);
+        _thread = new Thread(() => HookThreadMain(ready))
+        {
+            IsBackground = true,
+            Name = "LowLevelHookThread",
+        };
+        _thread.SetApartmentState(ApartmentState.STA);
+        _thread.Start();
+        ready.Wait();
+    }
+
+    private void HookThreadMain(ManualResetEventSlim ready)
+    {
+        _threadId = GetCurrentThreadId();
+        _kbProc = KeyboardProc;
+        _mouseProc = MouseProc;
+        var hMod = NativeMethods.GetModuleHandle(null);
+        _kbHook = NativeMethods.SetWindowsHookEx(NativeMethods.WH_KEYBOARD_LL, _kbProc, hMod, 0);
+        _mouseHook = NativeMethods.SetWindowsHookEx(NativeMethods.WH_MOUSE_LL, _mouseProc, hMod, 0);
+        ready.Set();
+
+        while (_running && NativeMethods.GetMessage(out var msg, IntPtr.Zero, 0, 0) > 0)
+        {
+            NativeMethods.TranslateMessage(ref msg);
+            NativeMethods.DispatchMessage(ref msg);
+        }
+
+        if (_kbHook != IntPtr.Zero) NativeMethods.UnhookWindowsHookEx(_kbHook);
+        if (_mouseHook != IntPtr.Zero) NativeMethods.UnhookWindowsHookEx(_mouseHook);
+        _kbHook = IntPtr.Zero;
+        _mouseHook = IntPtr.Zero;
+    }
+
+    private IntPtr KeyboardProc(int nCode, IntPtr wParam, IntPtr lParam)
+    {
+        if (nCode >= 0)
+        {
+            var data = System.Runtime.InteropServices.Marshal.PtrToStructure<NativeMethods.KBDLLHOOKSTRUCT>(lParam);
+            var msg = wParam.ToInt32();
+            var kind = msg switch
+            {
+                NativeMethods.WM_KEYDOWN or NativeMethods.WM_SYSKEYDOWN => "key_down",
+                NativeMethods.WM_KEYUP or NativeMethods.WM_SYSKEYUP => "key_up",
+                _ => "key",
+            };
+            _channel.Writer.TryWrite(new RawEvent(NowMs(), kind, 0, 0, data.vkCode, 0));
+        }
+        return NativeMethods.CallNextHookEx(IntPtr.Zero, nCode, wParam, lParam);
+    }
+
+    private IntPtr MouseProc(int nCode, IntPtr wParam, IntPtr lParam)
+    {
+        if (nCode >= 0)
+        {
+            var data = System.Runtime.InteropServices.Marshal.PtrToStructure<NativeMethods.MSLLHOOKSTRUCT>(lParam);
+            var msg = wParam.ToInt32();
+            var kind = msg switch
+            {
+                NativeMethods.WM_LBUTTONDOWN => "mouse_down_l",
+                NativeMethods.WM_LBUTTONUP => "mouse_up_l",
+                NativeMethods.WM_RBUTTONDOWN => "mouse_down_r",
+                NativeMethods.WM_RBUTTONUP => "mouse_up_r",
+                NativeMethods.WM_MBUTTONDOWN => "mouse_down_m",
+                NativeMethods.WM_MBUTTONUP => "mouse_up_m",
+                NativeMethods.WM_MOUSEWHEEL => "wheel",
+                NativeMethods.WM_MOUSEMOVE => "move",
+                _ => "mouse",
+            };
+            int wheel = 0;
+            if (msg == NativeMethods.WM_MOUSEWHEEL)
+            {
+                wheel = (short)((data.mouseData >> 16) & 0xFFFF);
+            }
+            _channel.Writer.TryWrite(new RawEvent(NowMs(), kind, data.pt.x, data.pt.y, 0, wheel));
+        }
+        return NativeMethods.CallNextHookEx(IntPtr.Zero, nCode, wParam, lParam);
+    }
+
+    private static long NowMs() => DateTimeOffset.UtcNow.ToUnixTimeMilliseconds();
+
+    [System.Runtime.InteropServices.DllImport("kernel32.dll")]
+    private static extern uint GetCurrentThreadId();
+
+    public void Dispose()
+    {
+        if (!_running) return;
+        _running = false;
+        if (_threadId != 0)
+        {
+            // Post a WM_QUIT to break GetMessage loop
+            PostThreadMessage(_threadId, 0x0012 /* WM_QUIT */, IntPtr.Zero, IntPtr.Zero);
+        }
+        _thread?.Join(1000);
+        _channel.Writer.TryComplete();
+    }
+
+    [System.Runtime.InteropServices.DllImport("user32.dll")]
+    private static extern bool PostThreadMessage(uint idThread, uint Msg, IntPtr wParam, IntPtr lParam);
+}