Fix virtual key mapping on MS Windows

In order to map MS Windows virtual keys to Qt keys without messing with
dead keys now I use the built-in keyMap structure of QWindowsKeyMapper
and assert every cell in the keymap is properly updated.

In order to guarantee this even when the user changes the keyboard
layout, WndProc now manages the WM_INPUTLANGCHANGE message, which is
handled by QWindowsKeyMapper, resetting the layout structure.

I don't fully understand yet some things about QWindowsKeyMapper, i.e.
how QWindowsKeyMapper::updatePossibleKeyCodes workarounds the dead key
issue with ToAscii; but it seems to work fine in all the tests I've
done. Any further testing is highly appreciated, though.

[ChangeLog][[QtGui][Platform Specific Changes][Windows] Fixed virtual key
mapping on Windows.

Task-number: QTBUG-33409
Task-number: QTBUG-8764
Task-number: QTBUG-10032

Change-Id: I4f7709a90906b03f4504deea1ff5c361e9f94b3f
(cherry picked from commit f0d014a16b5c9b55245834459c46ea34d15d14be)
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>

1 files changed, 12 insertions, 25 deletions

diff --git a/src/gui/kernel/qkeymapper_win.cpp b/src/gui/kernel/qkeymapper_win.cpp
index 34b0b4f..5a2e78e 100644
--- a/src/gui/kernel/qkeymapper_win.cpp
+++ b/src/gui/kernel/qkeymapper_win.cpp
@@ -662,7 +662,7 @@ void QKeyMapperPrivate::updateKeyMap(const MSG &msg)
 {
     unsigned char kbdBuffer[256]; // Will hold the complete keyboard state
     GetKeyboardState(kbdBuffer);
-    quint32 scancode = (msg.lParam >> 16) & 0xfff;
+    const quint32 scancode = (msg.lParam >> 16) & 0xff;
     updatePossibleKeyCodes(kbdBuffer, scancode, msg.wParam);
 }
 
@@ -797,10 +797,12 @@ bool QKeyMapperPrivate::translateKeyEvent(QWidget *widget, const MSG &msg, bool
     bool k0 = false;
     bool k1 = false;
     int  msgType = msg.message;
+    // Add this key to the keymap if it is not present yet.
+    updateKeyMap(msg);
+
+    const quint32 scancode = (msg.lParam >> 16) & 0xff;
+    const quint32 vk_key = msg.wParam;
 
-    quint32 scancode = (msg.lParam >> 16) & 0xfff;
-    quint32 vk_key = MapVirtualKey(scancode, 1);
-    bool isNumpad = (msg.wParam >= VK_NUMPAD0 && msg.wParam <= VK_NUMPAD9);
     quint32 nModifiers = 0;
 
 #if defined(Q_OS_WINCE)
@@ -835,10 +837,6 @@ bool QKeyMapperPrivate::translateKeyEvent(QWidget *widget, const MSG &msg, bool
     state |= (nModifiers & AltAny ? int(Qt::AltModifier) : 0);
     state |= (nModifiers & MetaAny ? int(Qt::MetaModifier) : 0);
 
-    // Now we know enough to either have MapVirtualKey or our own keymap tell us if it's a deadkey
-    bool isDeadKey = isADeadKey(msg.wParam, state)
-                     || MapVirtualKey(msg.wParam, 2) & 0x80000000;
-
     // A multi-character key not found by our look-ahead
     if (msgType == WM_CHAR) {
         QString s;
@@ -921,23 +919,12 @@ bool QKeyMapperPrivate::translateKeyEvent(QWidget *widget, const MSG &msg, bool
             return true;
 
         // Translate VK_* (native) -> Key_* (Qt) keys
-        // If it's a dead key, we cannot use the toKeyOrUnicode() function, since that will change
-        // the internal state of the keyboard driver, resulting in that dead keys no longer works.
-        // ..also if we're typing numbers on the keypad, while holding down the Alt modifier.
-        int code = 0;
-        if (isNumpad && (nModifiers & AltAny)) {
-            code = winceKeyBend(msg.wParam);
-        } else if (!isDeadKey) {
-            // QTBUG-8764, QTBUG-10032
-            // Can't call toKeyOrUnicode because that would call ToUnicode, and, if a dead key
-            // is pressed at the moment, Windows would NOT use it to compose a character for the next
-            // WM_CHAR event.
-
-            // Instead, use MapVirtualKey, which will provide adequate values.
-            code = MapVirtualKey(msg.wParam, MAPVK_VK_TO_CHAR);
-            if (code < 0x20 || code == 0x7f) // The same logic as in toKeyOrUnicode()
-                code = winceKeyBend(msg.wParam);
-        }
+        int modifiersIndex = 0;
+        modifiersIndex |= (nModifiers & ShiftAny ? 0x1 : 0);
+        modifiersIndex |= (nModifiers & ControlAny ? 0x2 : 0);
+        modifiersIndex |= (nModifiers & AltAny ? 0x4 : 0);
+
+        int code = keyLayout[vk_key]->qtKey[modifiersIndex];
 
         // Invert state logic:
         // If the key actually pressed is a modifier key, then we remove its modifier key from the