osu/osu.Desktop/Windows/WindowsKey.cs

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2020-07-01 15:15:41 +00:00
// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
// See the LICENCE file in the repository root for full licence text.
using System;
using System.Runtime.InteropServices;
namespace osu.Desktop.Windows
{
internal class WindowsKey
{
private delegate int LowLevelKeyboardProcDelegate(int nCode, int wParam, ref KdDllHookStruct lParam);
private static bool isBlocked;
private const int wh_keyboard_ll = 13;
private const int wm_keydown = 256;
private const int wm_syskeyup = 261;
//Resharper disable once NotAccessedField.Local
private static LowLevelKeyboardProcDelegate keyboardHookDelegate; // keeping a reference alive for the GC
private static IntPtr keyHook;
[StructLayout(LayoutKind.Explicit)]
private readonly struct KdDllHookStruct
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{
[FieldOffset(0)]
public readonly int VkCode;
[FieldOffset(8)]
public readonly int Flags;
}
private static int lowLevelKeyboardProc(int nCode, int wParam, ref KdDllHookStruct lParam)
{
if (wParam >= wm_keydown && wParam <= wm_syskeyup)
{
switch (lParam.VkCode)
{
case 0x5B: // left windows key
case 0x5C: // right windows key
return 1;
}
}
return callNextHookEx(0, nCode, wParam, ref lParam);
}
internal static void Disable()
{
if (keyHook != IntPtr.Zero || isBlocked)
return;
keyHook = setWindowsHookEx(wh_keyboard_ll, (keyboardHookDelegate = lowLevelKeyboardProc), Marshal.GetHINSTANCE(System.Reflection.Assembly.GetExecutingAssembly().GetModules()[0]), 0);
isBlocked = true;
}
internal static void Enable()
{
if (keyHook == IntPtr.Zero || !isBlocked)
return;
keyHook = unhookWindowsHookEx(keyHook);
keyboardHookDelegate = null;
keyHook = IntPtr.Zero;
isBlocked = false;
}
[DllImport(@"user32.dll", EntryPoint = @"SetWindowsHookExA")]
private static extern IntPtr setWindowsHookEx(int idHook, LowLevelKeyboardProcDelegate lpfn, IntPtr hMod, int dwThreadId);
[DllImport(@"user32.dll", EntryPoint = @"UnhookWindowsHookEx")]
private static extern IntPtr unhookWindowsHookEx(IntPtr hHook);
[DllImport(@"user32.dll", EntryPoint = @"CallNextHookEx")]
private static extern int callNextHookEx(int hHook, int nCode, int wParam, ref KdDllHookStruct lParam);
}
}