macOS: Modernize QCocoaKeyMapper key map

Change-Id: I3e8a4cfa611b6ae575466c493aac438dc831e89a
Reviewed-by: Timur Pocheptsov <timur.pocheptsov@qt.io>

src/plugins/platforms/cocoa/qcocoakeymapper.h

@@ -69,16 +69,10 @@ QT_BEGIN_NAMESPACE
         15. Meta + Alt + Control
         16. Meta + Alt + Control + Shift
 */
-struct KeyboardLayoutItem {
-    quint32 qtKey[16]; // Can by any Qt::Key_<foo>, or unicode character
-};
-
 
 class QCocoaKeyMapper
 {
 public:
-    QCocoaKeyMapper();
-    ~QCocoaKeyMapper();
     static Qt::KeyboardModifiers queryKeyboardModifiers();
     QList<int> possibleKeys(const QKeyEvent *event) const;
 
@@ -89,9 +83,18 @@ public:
     static Qt::Key fromCocoaKey(QChar keyCode);
 
 private:
+    using VirtualKeyCode = unsigned short;
+    struct KeyMap : std::array<char32_t, 16>
+    {
+        // Initialize first element to a sentinel that allows us
+        // to distinguish an uninitialized map from an initialized.
+        // Using 0 would not allow us to map U+0000 (NUL), however
+        // unlikely that is.
+        KeyMap() : std::array<char32_t, 16>{Qt::Key_unknown} {}
+    };
+
     bool updateKeyboard();
-    void deleteLayouts();
+    const KeyMap &keyMapForKey(VirtualKeyCode virtualKey, QChar unicodeKey) const;
-    KeyboardLayoutItem *keyMapForKey(unsigned short macVirtualKey, QChar unicodeKey) const;
 
     QCFType<TISInputSourceRef> m_currentInputSource = nullptr;
 
@@ -99,7 +102,8 @@ private:
     const UCKeyboardLayout *m_keyboardLayoutFormat = nullptr;
     KeyboardLayoutKind m_keyboardKind = kKLKCHRuchrKind;
     mutable UInt32 m_deadKeyState = 0; // Maintains dead key state beween calls to UCKeyTranslate
-    mutable KeyboardLayoutItem *m_keyLayout[256];
+
+    mutable QHash<VirtualKeyCode, KeyMap> m_keyMap;
 };
 
 QT_END_NAMESPACE

src/plugins/platforms/cocoa/qcocoakeymapper.mm

@@ -381,16 +381,6 @@ Qt::Key QCocoaKeyMapper::fromCocoaKey(QChar keyCode)
 
 // ------------------------------------------------
 
-QCocoaKeyMapper::QCocoaKeyMapper()
-{
-    memset(m_keyLayout, 0, sizeof(m_keyLayout));
-}
-
-QCocoaKeyMapper::~QCocoaKeyMapper()
-{
-    deleteLayouts();
-}
-
 Qt::KeyboardModifiers QCocoaKeyMapper::queryKeyboardModifiers()
 {
     return fromCocoaModifiers(NSEvent.modifierFlags);
@@ -410,7 +400,7 @@ bool QCocoaKeyMapper::updateKeyboard()
     m_keyboardKind = LMGetKbdType();
     m_deadKeyState = 0;
 
-    deleteLayouts();
+    m_keyMap.clear();
 
     if (auto data = CFDataRef(TISGetInputSourceProperty(source, kTISPropertyUnicodeKeyLayoutData))) {
         const UCKeyboardLayout *uchrData = reinterpret_cast<const UCKeyboardLayout *>(CFDataGetBytePtr(data));
@@ -429,17 +419,6 @@ bool QCocoaKeyMapper::updateKeyboard()
     return true;
 }
 
-void QCocoaKeyMapper::deleteLayouts()
-{
-    m_keyboardMode = NullMode;
-    for (int i = 0; i < 255; ++i) {
-        if (m_keyLayout[i]) {
-            delete m_keyLayout[i];
-            m_keyLayout[i] = nullptr;
-        }
-    }
-}
-
 static constexpr Qt::KeyboardModifiers modifierCombinations[] = {
     Qt::NoModifier,                                             // 0
     Qt::ShiftModifier,                                          // 1
@@ -460,31 +439,31 @@ static constexpr Qt::KeyboardModifiers modifierCombinations[] = {
 };
 
 /*
-    Returns a key map for the given \macVirtualKey based on all
+    Returns a key map for the given \virtualKey based on all
     possible modifier combinations.
 */
-KeyboardLayoutItem *QCocoaKeyMapper::keyMapForKey(unsigned short macVirtualKey, QChar unicodeKey) const
+const QCocoaKeyMapper::KeyMap &QCocoaKeyMapper::keyMapForKey(VirtualKeyCode virtualKey, QChar unicodeKey) const
 {
     const_cast<QCocoaKeyMapper *>(this)->updateKeyboard();
 
-    Q_ASSERT(macVirtualKey < 256);
+    auto &keyMap = m_keyMap[virtualKey];
-    if (auto *existingKeyMap = m_keyLayout[macVirtualKey])
+    if (keyMap[Qt::NoModifier] != Qt::Key_unknown)
-        return existingKeyMap;
+        return keyMap; // Already filled
 
-    qCDebug(lcQpaKeyMapper, "Updating key map for virtual key = 0x%02x!", (uint)macVirtualKey);
+    qCDebug(lcQpaKeyMapper, "Updating key map for virtual key = 0x%02x!", (uint)virtualKey);
 
     UniCharCount maxStringLength = 10;
     UniChar unicodeString[maxStringLength];
-    m_keyLayout[macVirtualKey] = new KeyboardLayoutItem;
 
     for (int i = 0; i < 16; ++i) {
-        UniCharCount actualStringLength = 0;
+        Q_ASSERT(!i || keyMap[i] == 0);
-        m_keyLayout[macVirtualKey]->qtKey[i] = 0;
 
         auto qtModifiers = modifierCombinations[i];
         auto carbonModifiers = toCarbonModifiers(qtModifiers);
         const UInt32 modifierKeyState = (carbonModifiers >> 8) & 0xFF;
-        OSStatus err = UCKeyTranslate(m_keyboardLayoutFormat, macVirtualKey,
+
+        UniCharCount actualStringLength = 0;
+        OSStatus err = UCKeyTranslate(m_keyboardLayoutFormat, virtualKey,
             kUCKeyActionDown, modifierKeyState, m_keyboardKind, OptionBits(0),
             &m_deadKeyState, maxStringLength, &actualStringLength, unicodeString);
 
@@ -492,36 +471,36 @@ KeyboardLayoutItem *QCocoaKeyMapper::keyMapForKey(unsigned short macVirtualKey,
         if (err == noErr && actualStringLength)
             unicodeKey = QChar(unicodeString[0]);
 
-        int qtkey = toKeyCode(unicodeKey, macVirtualKey, qtModifiers);
+        int qtkey = toKeyCode(unicodeKey, virtualKey, qtModifiers);
         if (qtkey == Qt::Key_unknown)
             qtkey = unicodeKey.unicode();
 
-        m_keyLayout[macVirtualKey]->qtKey[i] = qtkey;
+        keyMap[i] = qtkey;
 
         qCDebug(lcQpaKeyMapper, "    [%d] (%d,0x%02x,'%c')", i, qtkey, qtkey, qtkey);
     }
 
-    return m_keyLayout[macVirtualKey];
+    return keyMap;
 }
 
 QList<int> QCocoaKeyMapper::possibleKeys(const QKeyEvent *event) const
 {
     QList<int> ret;
 
-    auto *keyMap = keyMapForKey(event->nativeVirtualKey(), QChar(event->key()));
+    auto keyMap = keyMapForKey(event->nativeVirtualKey(), QChar(event->key()));
-    Q_ASSERT(keyMap);
+
+    auto unmodifiedKey = keyMap[Qt::NoModifier];
+    Q_ASSERT(unmodifiedKey != Qt::Key_unknown);
 
-    int baseKey = keyMap->qtKey[Qt::NoModifier];
     auto eventModifiers = event->modifiers();
 
-    // The base key is always valid
+    // The base key, with the complete set of modifiers,
-    ret << int(baseKey + eventModifiers);
+    // is always valid, and the first priority.
+    ret << int(unmodifiedKey + eventModifiers);
 
     for (int i = 1; i < 8; ++i) {
-        int keyAfterApplyingModifiers = keyMap->qtKey[i];
+        auto keyAfterApplyingModifiers = keyMap[i];
-        if (!keyAfterApplyingModifiers)
+        if (keyAfterApplyingModifiers == unmodifiedKey)
-            continue;
-        if (keyAfterApplyingModifiers == baseKey)
             continue;
 
         // Include key if event modifiers includes, or matches