Report modifiers correctly in mouse events with evdev and libinput

Task-number: QTBUG-60694
Change-Id: I7b1625e5f31e49cd2ab18a83bbd0f65f9b58088d
Reviewed-by: Andy Nichols <andy.nichols@qt.io>

src/gui/kernel/qinputdevicemanager.cpp

@@ -92,4 +92,48 @@ void QInputDeviceManager::setCursorPos(const QPoint &pos)
     emit cursorPositionChangeRequested(pos);
 }
 
+/*!
+    \return the keyboard modifier state stored in the QInputDeviceManager object.
+
+    Keyboard input handlers are expected to keep this up-to-date via
+    setKeyboardModifiers().
+
+    Querying the state via this function (e.g. from a mouse handler that needs
+    to include the modifier state in mouse events) is the preferred alternative
+    over QGuiApplication::keyboardModifiers() since the latter may not report
+    the current state due to asynchronous QPA event processing.
+ */
+Qt::KeyboardModifiers QInputDeviceManager::keyboardModifiers() const
+{
+    Q_D(const QInputDeviceManager);
+    return d->keyboardModifiers;
+}
+
+void QInputDeviceManager::setKeyboardModifiers(Qt::KeyboardModifiers modsBeforeEvent, int key)
+{
+    Q_D(QInputDeviceManager);
+    Qt::KeyboardModifiers mods;
+    switch (key) {
+    case Qt::Key_Shift:
+        mods = Qt::KeyboardModifiers(modsBeforeEvent ^ Qt::ShiftModifier);
+        break;
+    case Qt::Key_Control:
+        mods = Qt::KeyboardModifiers(modsBeforeEvent ^ Qt::ControlModifier);
+        break;
+    case Qt::Key_Alt:
+        mods = Qt::KeyboardModifiers(modsBeforeEvent ^ Qt::AltModifier);
+        break;
+    case Qt::Key_Meta:
+        mods = Qt::KeyboardModifiers(modsBeforeEvent ^ Qt::MetaModifier);
+        break;
+    case Qt::Key_AltGr:
+        mods = Qt::KeyboardModifiers(modsBeforeEvent ^ Qt::GroupSwitchModifier);
+        break;
+    default:
+        mods = modsBeforeEvent;
+        break;
+    }
+    d->keyboardModifiers = mods;
+}
+
 QT_END_NAMESPACE

src/gui/kernel/qinputdevicemanager_p.h

@@ -78,6 +78,9 @@ public:
 
     void setCursorPos(const QPoint &pos);
 
+    Qt::KeyboardModifiers keyboardModifiers() const;
+    void setKeyboardModifiers(Qt::KeyboardModifiers modsBeforeEvent, int key);
+
 signals:
     void deviceListChanged(QInputDeviceManager::DeviceType type);
     void cursorPositionChangeRequested(const QPoint &pos);

src/gui/kernel/qinputdevicemanager_p_p.h

@@ -69,6 +69,8 @@ public:
     void setDeviceCount(QInputDeviceManager::DeviceType type, int count);
 
     QMap<QInputDeviceManager::DeviceType, int> m_deviceCount;
+
+    Qt::KeyboardModifiers keyboardModifiers;
 };
 
 QT_END_NAMESPACE

src/platformsupport/input/evdevkeyboard/qevdevkeyboardhandler.cpp

@@ -49,6 +49,9 @@
 #include <qpa/qwindowsysteminterface.h>
 #include <private/qcore_unix_p.h>
 
+#include <QtGui/private/qguiapplication_p.h>
+#include <QtGui/private/qinputdevicemanager_p.h>
+
 #ifdef Q_OS_FREEBSD
 #include <dev/evdev/input.h>
 #else
@@ -222,6 +225,8 @@ void QEvdevKeyboardHandler::readKeycode()
 void QEvdevKeyboardHandler::processKeyEvent(int nativecode, int unicode, int qtcode,
                                             Qt::KeyboardModifiers modifiers, bool isPress, bool autoRepeat)
 {
+    QGuiApplicationPrivate::inputDeviceManager()->setKeyboardModifiers(modifiers, qtcode);
+
     QWindowSystemInterface::handleExtendedKeyEvent(0, (isPress ? QEvent::KeyPress : QEvent::KeyRelease),
                                                    qtcode, modifiers, nativecode + 8, 0, int(modifiers),
                                                    (unicode != 0xffff ) ? QString(unicode) : QString(), autoRepeat);
@@ -403,6 +408,8 @@ QEvdevKeyboardHandler::KeycodeAction QEvdevKeyboardHandler::processKeycode(quint
             Qt::KeyboardModifiers qtmods = Qt::KeyboardModifiers(qtcode & modmask);
             qtcode &= ~modmask;
 
+            // qtmods here is the modifier state before the event, i.e. not
+            // including the current key in case it is a modifier.
             qCDebug(qLcEvdevKeyMap, "Processing: uni=%04x, qt=%08x, qtmod=%08x", unicode, qtcode, int(qtmods));
 
             // If NumLockOff and keypad key pressed remap event sent

src/platformsupport/input/libinput/qlibinputkeyboard.cpp

@@ -40,6 +40,8 @@
 #include "qlibinputkeyboard_p.h"
 #include <QtCore/QTextCodec>
 #include <QtCore/QLoggingCategory>
+#include <QtGui/private/qguiapplication_p.h>
+#include <QtGui/private/qinputdevicemanager_p.h>
 #include <qpa/qwindowsysteminterface.h>
 #include <libinput.h>
 #ifndef QT_NO_XKBCOMMON_EVDEV
@@ -196,6 +198,8 @@ void QLibInputKeyboard::processKey(libinput_event_keyboard *e)
 
     const xkb_keysym_t sym = xkb_state_key_get_one_sym(m_state, k);
 
+    // mods here is the modifier state before the event, i.e. not
+    // including the current key in case it is a modifier.
     Qt::KeyboardModifiers mods = Qt::NoModifier;
     const int qtkey = keysymToQtKey(sym, &mods, text);
 
@@ -211,6 +215,8 @@ void QLibInputKeyboard::processKey(libinput_event_keyboard *e)
 
     xkb_state_update_key(m_state, k, pressed ? XKB_KEY_DOWN : XKB_KEY_UP);
 
+    QGuiApplicationPrivate::inputDeviceManager()->setKeyboardModifiers(mods, qtkey);
+
     QWindowSystemInterface::handleExtendedKeyEvent(Q_NULLPTR,
                                                    pressed ? QEvent::KeyPress : QEvent::KeyRelease,
                                                    qtkey, mods, k, sym, mods, text);

src/platformsupport/input/libinput/qlibinputpointer.cpp

@@ -41,6 +41,8 @@
 #include <libinput.h>
 #include <QtGui/QGuiApplication>
 #include <QtGui/QScreen>
+#include <QtGui/private/qguiapplication_p.h>
+#include <QtGui/private/qinputdevicemanager_p.h>
 #include <qpa/qwindowsysteminterface.h>
 #include <private/qhighdpiscaling_p.h>
 
@@ -78,7 +80,8 @@ void QLibInputPointer::processButton(libinput_event_pointer *e)
 
     m_buttons.setFlag(button, pressed);
 
-    QWindowSystemInterface::handleMouseEvent(Q_NULLPTR, m_pos, m_pos, m_buttons, QGuiApplication::keyboardModifiers());
+    QWindowSystemInterface::handleMouseEvent(Q_NULLPTR, m_pos, m_pos, m_buttons,
+                                             QGuiApplicationPrivate::inputDeviceManager()->keyboardModifiers());
 }
 
 void QLibInputPointer::processMotion(libinput_event_pointer *e)
@@ -91,7 +94,8 @@ void QLibInputPointer::processMotion(libinput_event_pointer *e)
     m_pos.setX(qBound(g.left(), qRound(m_pos.x() + dx), g.right()));
     m_pos.setY(qBound(g.top(), qRound(m_pos.y() + dy), g.bottom()));
 
-    QWindowSystemInterface::handleMouseEvent(Q_NULLPTR, m_pos, m_pos, m_buttons, QGuiApplication::keyboardModifiers());
+    QWindowSystemInterface::handleMouseEvent(Q_NULLPTR, m_pos, m_pos, m_buttons,
+                                             QGuiApplicationPrivate::inputDeviceManager()->keyboardModifiers());
 }
 
 void QLibInputPointer::processAxis(libinput_event_pointer *e)
@@ -100,15 +104,18 @@ void QLibInputPointer::processAxis(libinput_event_pointer *e)
     const double v = libinput_event_pointer_get_axis_value(e) * 120;
     const Qt::Orientation ori = libinput_event_pointer_get_axis(e) == LIBINPUT_POINTER_AXIS_SCROLL_VERTICAL
         ? Qt::Vertical : Qt::Horizontal;
-    QWindowSystemInterface::handleWheelEvent(Q_NULLPTR, m_pos, m_pos, qRound(-v), ori, QGuiApplication::keyboardModifiers());
+    QWindowSystemInterface::handleWheelEvent(Q_NULLPTR, m_pos, m_pos, qRound(-v), ori,
+                                             QGuiApplicationPrivate::inputDeviceManager()->keyboardModifiers());
 #else
     if (libinput_event_pointer_has_axis(e, LIBINPUT_POINTER_AXIS_SCROLL_VERTICAL)) {
         const double v = libinput_event_pointer_get_axis_value(e, LIBINPUT_POINTER_AXIS_SCROLL_VERTICAL) * 120;
-        QWindowSystemInterface::handleWheelEvent(Q_NULLPTR, m_pos, m_pos, qRound(-v), Qt::Vertical, QGuiApplication::keyboardModifiers());
+        QWindowSystemInterface::handleWheelEvent(Q_NULLPTR, m_pos, m_pos, qRound(-v), Qt::Vertical,
+                                                 QGuiApplicationPrivate::inputDeviceManager()->keyboardModifiers());
     }
     if (libinput_event_pointer_has_axis(e, LIBINPUT_POINTER_AXIS_SCROLL_HORIZONTAL)) {
         const double v = libinput_event_pointer_get_axis_value(e, LIBINPUT_POINTER_AXIS_SCROLL_HORIZONTAL) * 120;
-        QWindowSystemInterface::handleWheelEvent(Q_NULLPTR, m_pos, m_pos, qRound(-v), Qt::Horizontal, QGuiApplication::keyboardModifiers());
+        QWindowSystemInterface::handleWheelEvent(Q_NULLPTR, m_pos, m_pos, qRound(-v), Qt::Horizontal,
+                                                 QGuiApplicationPrivate::inputDeviceManager()->keyboardModifiers());
     }
 #endif
 }