Flow.Launcher/Flow.Launcher.Infrastructure/Hotkey/InterceptKeys.cs

using System;
using System.Diagnostics;
using System.Runtime.InteropServices;

namespace Flow.Launcher.Infrastructure.Hotkey
{
    internal static unsafe class InterceptKeys
    {
        public delegate IntPtr LowLevelKeyboardProc(int nCode, UIntPtr wParam, IntPtr lParam);

        private const int WH_KEYBOARD_LL = 13;

        public static IntPtr SetHook(delegate* unmanaged<int, UIntPtr, IntPtr, IntPtr> proc)
        {
            using (Process curProcess = Process.GetCurrentProcess())
            using (ProcessModule curModule = curProcess.MainModule)
            {
                return SetWindowsHookEx(WH_KEYBOARD_LL, proc, GetModuleHandle(curModule.ModuleName), 0);
            }
        }

        [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
        public static extern IntPtr SetWindowsHookEx(int idHook, delegate* unmanaged<int, UIntPtr, IntPtr, IntPtr> lpfn, IntPtr hMod, uint dwThreadId);

        [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
        [return: MarshalAs(UnmanagedType.Bool)]
        public static extern bool UnhookWindowsHookEx(IntPtr hhk);

        [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
        public static extern IntPtr CallNextHookEx(IntPtr hhk, int nCode, UIntPtr wParam, IntPtr lParam);

        [DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)]
        public static extern IntPtr GetModuleHandle(string lpModuleName);

        [DllImport("user32.dll", CharSet = CharSet.Auto, ExactSpelling = true, CallingConvention = CallingConvention.Winapi)]
        public static extern short GetKeyState(int keyCode);
    }
}