Introduce QInputDevice hierarchy; replace QTouchDevice

We have seen during the Qt 5 series that QMouseEvent::source() does
not provide enough information: if it is synthesized, it could have
come from any device for which mouse events are synthesized, not only
from a touchscreen. By providing in every QInputEvent as complete
information about the actual source device as possible, we will enable
very fine-tuned behavior in the object that handles each event.

Further, we would like to support multiple keyboards, pointing devices,
and named groups of devices that are known as "seats" in Wayland.

In Qt 5, QPA plugins registered each touchscreen as it was discovered.
Now we extend this pattern to all input devices.  This new requirement
can be implemented gradually; for now, if a QTWSI input event is
received wtihout a device pointer, a default "core" device will be
created on-the-fly, and a warning emitted.

In Qt 5, QTouchEvent::TouchPoint::id() was forced to be unique even when
multiple devices were in use simultaneously. Now that each event
identifies the device it came from, this hack is no longer needed.

A stub of the new QPointerEvent is added; it will be developed further
in subsequent patches.

[ChangeLog][QtGui][QInputEvent] Every QInputEvent now carries a pointer
to an instance of QInputDevice, or the subclass QPointingDevice in case
of mouse, touch and tablet events. Each platform plugin is expected to
create the device instances, register them, and provide valid pointers
with all input events. If this is not done, warnings are emitted and
default devices are created as necessary. When the device has accurate
information, it provides the opportunity to fine-tune behavior depending
on device type and capabilities: for example if a QMouseEvent is
synthesized from a touchscreen, the recipient can see which touchscreen
it came from. Each device also has a seatName to distinguish users on
multi-user windowing systems. Touchpoint IDs are no longer unique on
their own, but the combination of ID and device is.

Fixes: QTBUG-46412
Fixes: QTBUG-72167
Task-number: QTBUG-69433
Task-number: QTBUG-52430
Change-Id: I933fb2b86182efa722037b7a33e404c5daf5292a
Reviewed-by: Shawn Rutledge <shawn.rutledge@qt.io>

1 files changed, 130 insertions, 0 deletions

diff --git a/src/gui/kernel/qinputdevice.h b/src/gui/kernel/qinputdevice.h
new file mode 100644
index 0000000000..d20f76af2e
--- /dev/null
+++ b/src/gui/kernel/qinputdevice.h
@@ -0,0 +1,130 @@
+/****************************************************************************
+**
+** Copyright (C) 2020 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the QtGui module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
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+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QINPUTDEVICE_H
+#define QINPUTDEVICE_H
+
+#include <QtGui/qtguiglobal.h>
+#include <QtCore/qobject.h>
+#include <QtGui/qscreen.h>
+
+QT_BEGIN_NAMESPACE
+
+class QDebug;
+class QInputDevicePrivate;
+
+class Q_GUI_EXPORT QInputDevice : public QObject
+{
+    Q_OBJECT
+    Q_DECLARE_PRIVATE(QInputDevice)
+    Q_PROPERTY(QString name READ name CONSTANT)
+    Q_PROPERTY(DeviceType type READ type CONSTANT)
+    Q_PROPERTY(Capabilities capabilities READ capabilities CONSTANT)
+    Q_PROPERTY(qint64 id READ id CONSTANT)
+    Q_PROPERTY(QString seatName READ seatName CONSTANT)
+
+public:
+    enum class DeviceType : qint16 {
+        Unknown = 0x0000,
+        Mouse = 0x0001,
+        TouchScreen = 0x0002,
+        TouchPad = 0x0004,
+        Puck = 0x0008,
+        Stylus = 0x0010,
+        Airbrush = 0x0020,
+        Keyboard = 0x1000,
+        AllDevices = 0x7FFF
+    };
+    Q_DECLARE_FLAGS(DeviceTypes, DeviceType)
+    Q_FLAG(DeviceTypes)
+
+    enum class Capability : qint32 {
+        None = 0,
+        Position = 0x0001,
+        Area = 0x0002,
+        Pressure = 0x0004,
+        Velocity = 0x0008,
+        RawPositions = 0x0010,
+        NormalizedPosition = 0x0020,
+        MouseEmulation = 0x0040,
+        Scroll      = 0x0100,
+        Hover       = 0x0200,
+        Rotation    = 0x0400,
+        XTilt       = 0x0800,
+        YTilt       = 0x1000,
+        TangentialPressure = 0x2000,
+        ZPosition   = 0x4000,
+        All = 0x7FFFFFFF
+    };
+    Q_DECLARE_FLAGS(Capabilities, Capability)
+    Q_FLAG(Capabilities)
+
+    QInputDevice();
+    ~QInputDevice();
+    QInputDevice(const QString &name, qint64 id, DeviceType type,
+                 const QString &seatName = QString(), QObject *parent = nullptr);
+
+    QString name() const;
+    DeviceType type() const;
+    Capabilities capabilities() const;
+    bool hasCapability(Capability cap) const;
+    qint64 id() const;
+    QString seatName() const;
+
+    static QVector<const QInputDevice *> devices();
+    static const QInputDevice *primaryKeyboard(const QString& seatName = QString());
+
+    bool operator==(const QInputDevice &other) const;
+
+protected:
+    QInputDevice(QInputDevicePrivate &d, QObject *parent = nullptr);
+
+    Q_DISABLE_COPY_MOVE(QInputDevice)
+};
+
+Q_DECLARE_OPERATORS_FOR_FLAGS(QInputDevice::DeviceTypes)
+Q_DECLARE_OPERATORS_FOR_FLAGS(QInputDevice::Capabilities)
+
+#ifndef QT_NO_DEBUG_STREAM
+Q_GUI_EXPORT QDebug operator<<(QDebug, const QInputDevice *);
+#endif
+
+QT_END_NAMESPACE
+
+#endif // QINPUTDEVICE_H