Add alternative method to poll keyboard state on Windows

It seems that Windows is frequently disconnecting the keyboard hook
(eventually if swift was too busy processing messages) and caused all hotkeys
to be unreliable.
Instead use a polling mechanism. The previous method is kept in code for
testing, but is disabled by compile time switch.

src/blackinput/win/keyboardwindows.cpp

@@ -68,7 +68,9 @@ namespace BlackInput
     CKeyboardWindows::CKeyboardWindows(QObject *parent) :
         IKeyboard(parent),
         m_keyboardHook(nullptr)
-    { }
+    {
+        connect(&m_pollTimer, &QTimer::timeout, this, &CKeyboardWindows::pollKeyboardState);
+    }
 
     CKeyboardWindows::~CKeyboardWindows()
     {
@@ -77,9 +79,17 @@ namespace BlackInput
 
     bool CKeyboardWindows::init()
     {
-        Q_ASSERT_X(g_keyboardWindows == nullptr, "CKeyboardWindows::init", "Windows supports only one keyboard instance. Cannot initialize a second one!");
-        g_keyboardWindows = this;
-        m_keyboardHook = SetWindowsHookEx(WH_KEYBOARD_LL, CKeyboardWindows::keyboardProc, GetModuleHandle(nullptr), 0);
+        if (useWindowsHook)
+        {
+            Q_ASSERT_X(g_keyboardWindows == nullptr, "CKeyboardWindows::init", "Windows supports only one keyboard instance. Cannot initialize a second one!");
+            g_keyboardWindows = this;
+            HMODULE module;
+            GetModuleHandleEx(GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS | GET_MODULE_HANDLE_EX_FLAG_UNCHANGED_REFCOUNT, reinterpret_cast<LPCTSTR>(&CKeyboardWindows::keyboardProc), &module);
+            m_keyboardHook = SetWindowsHookEx(WH_KEYBOARD_LL, CKeyboardWindows::keyboardProc, module, 0);
+        }
+        {
+            m_pollTimer.start(50);
+        }
         return true;
     }
 
@@ -105,6 +115,36 @@ namespace BlackInput
         }
     }
 
+    void CKeyboardWindows::pollKeyboardState()
+    {
+        BlackMisc::Input::CHotkeyCombination oldCombination(m_keyCombination);
+        QList<int> vkeys = keyMapping().keys();
+        for (int vkey : vkeys)
+        {
+            if ((GetKeyState(vkey) & 0x8000) && !m_pressedKeys.contains(vkey))
+            {
+                // key down
+                auto key = keyMapping().value(vkey);
+                if (key == Key_Unknown) { return; }
+                m_pressedKeys.push_back(vkey);
+                m_keyCombination.addKeyboardKey(CKeyboardKey(key));
+            }
+            else if (!(GetKeyState(vkey) & 0x8000) && m_pressedKeys.contains(vkey))
+            {
+                // key up
+                auto key = keyMapping().value(vkey);
+                if (key == Key_Unknown) { return; }
+                m_pressedKeys.removeAll(vkey);
+                m_keyCombination.removeKeyboardKey(CKeyboardKey(key));
+            }
+        }
+
+        if (oldCombination != m_keyCombination)
+        {
+            emit keyCombinationChanged(m_keyCombination);
+        }
+    }
+
     LRESULT CALLBACK CKeyboardWindows::keyboardProc(int nCode, WPARAM wParam, LPARAM lParam)
     {
         if (nCode == HC_ACTION)
@@ -113,6 +153,6 @@ namespace BlackInput
             DWORD vkCode = keyboardEvent->vkCode;
             g_keyboardWindows->processKeyEvent(vkCode, wParam);
         }
-        return CallNextHookEx(g_keyboardWindows->keyboardHook(), nCode, wParam, lParam);
+        return CallNextHookEx(g_keyboardWindows->m_keyboardHook, nCode, wParam, lParam);
     }
 }

src/blackinput/win/keyboardwindows.h

@@ -19,6 +19,7 @@
 #include "blackmisc/input/keyboardkey.h"
 #include "blackmisc/input/keyboardkeylist.h"
 #include <QHash>
+#include <QTimer>
 #ifndef NOMINMAX
 #define NOMINMAX
 #endif
@@ -41,9 +42,6 @@ namespace BlackInput
         //! Destructor
         virtual ~CKeyboardWindows() override;
 
-        //! Keyboard hook handle
-        HHOOK keyboardHook() const { return m_keyboardHook; }
-
     protected:
         //! \copydoc IKeyboard::init()
         virtual bool init() override;
@@ -57,12 +55,17 @@ namespace BlackInput
         void addKey(WPARAM vkcode);
         void removeKey(WPARAM vkcode);
         void processKeyEvent(DWORD vkCode, WPARAM event);
+        void pollKeyboardState();
+
+        const bool useWindowsHook = false;
 
         //! Keyboard hook procedure
         static LRESULT CALLBACK keyboardProc(int nCode, WPARAM wParam, LPARAM lParam);
 
         BlackMisc::Input::CHotkeyCombination m_keyCombination; //!< Set of virtual keys pressed in the last cycle
         HHOOK m_keyboardHook; //!< Keyboard hook handle
+        QTimer m_pollTimer;
+        QVector<int> m_pressedKeys;
     };
 }