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, 149 insertions, 0 deletions

diff --git a/src/gui/kernel/qpointingdevice.h b/src/gui/kernel/qpointingdevice.h
new file mode 100644
index 0000000000..a823af4ec9
--- /dev/null
+++ b/src/gui/kernel/qpointingdevice.h
@@ -0,0 +1,149 @@
+/****************************************************************************
+**
+** 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.
+**
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+** GNU Lesser General Public License Usage
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+** 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.
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+** $QT_END_LICENSE$
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+****************************************************************************/
+
+#ifndef QPOINTINGDEVICE_H
+#define QPOINTINGDEVICE_H
+
+#include <QtGui/qtguiglobal.h>
+#include <QtCore/qobject.h>
+#include <QtGui/qinputdevice.h>
+
+QT_BEGIN_NAMESPACE
+
+class QDebug;
+class QPointingDevicePrivate;
+class QScreen;
+
+class Q_GUI_EXPORT QPointingDeviceUniqueId
+{
+    Q_GADGET
+    Q_PROPERTY(qint64 numericId READ numericId CONSTANT)
+public:
+    Q_ALWAYS_INLINE
+    Q_DECL_CONSTEXPR QPointingDeviceUniqueId() noexcept : m_numericId(-1) {}
+    // compiler-generated copy/move ctor/assignment operators are ok!
+    // compiler-generated dtor is ok!
+
+    static QPointingDeviceUniqueId fromNumericId(qint64 id);
+
+    Q_ALWAYS_INLINE Q_DECL_CONSTEXPR bool isValid() const noexcept { return m_numericId != -1; }
+    qint64 numericId() const noexcept;
+
+private:
+    // TODO: for TUIO 2, or any other type of complex token ID, an internal
+    // array (or hash) can be added to hold additional properties.
+    // In this case, m_numericId will then turn into an index into that array (or hash).
+    qint64 m_numericId;
+};
+Q_DECLARE_TYPEINFO(QPointingDeviceUniqueId, Q_MOVABLE_TYPE);
+
+Q_GUI_EXPORT bool operator==(QPointingDeviceUniqueId lhs, QPointingDeviceUniqueId rhs) noexcept;
+inline bool operator!=(QPointingDeviceUniqueId lhs, QPointingDeviceUniqueId rhs) noexcept
+{ return !operator==(lhs, rhs); }
+Q_GUI_EXPORT size_t qHash(QPointingDeviceUniqueId key, size_t seed = 0) noexcept;
+
+class Q_GUI_EXPORT QPointingDevice : public QInputDevice
+{
+    Q_OBJECT
+    Q_DECLARE_PRIVATE(QPointingDevice)
+    Q_PROPERTY(PointerType pointerType READ pointerType)
+    Q_PROPERTY(int maximumPoints READ maximumPoints)
+    Q_PROPERTY(int buttonCount READ buttonCount)
+    Q_PROPERTY(QPointingDeviceUniqueId uniqueId READ uniqueId)
+
+public:
+    enum class PointerType : qint16 {
+        Unknown = 0,
+        Generic = 0x0001,   // mouse or similar
+        Finger = 0x0002,    // touchscreen or pad
+        Pen = 0x0004,       // stylus on a tablet
+        Eraser = 0x0008,    // eraser end of a stylus
+        Cursor = 0x0010,    // digitizer with crosshairs
+        AllPointerTypes = 0x7FFF
+    };
+    Q_DECLARE_FLAGS(PointerTypes, PointerType)
+    Q_FLAG(PointerTypes)
+
+    QPointingDevice();
+    ~QPointingDevice();
+    QPointingDevice(const QString &name, qint64 id, QInputDevice::DeviceType devType,
+                    PointerType pType, Capabilities caps, int maxPoints, int buttonCount,
+                    const QString &seatName = QString(),
+                    QPointingDeviceUniqueId uniqueId = QPointingDeviceUniqueId(),
+                    QObject *parent = nullptr);
+
+#if QT_DEPRECATED_SINCE(6, 0)
+    QT_DEPRECATED_VERSION_X_6_0("Use the constructor")
+    void setType(DeviceType devType);
+    QT_DEPRECATED_VERSION_X_6_0("Use the constructor")
+    void setCapabilities(QInputDevice::Capabilities caps);
+    QT_DEPRECATED_VERSION_X_6_0("Use the constructor")
+    void setMaximumTouchPoints(int c);
+#endif
+
+    PointerType pointerType() const;
+    int maximumPoints() const;
+    int buttonCount() const;
+    QPointingDeviceUniqueId uniqueId() const;
+
+    static const QPointingDevice *primaryPointingDevice(const QString& seatName = QString());
+
+    static const QPointingDevice *tabletDevice(QInputDevice::DeviceType deviceType,
+                                               QPointingDevice::PointerType pointerType,
+                                               QPointingDeviceUniqueId uniqueId, quint32 usbId = 0);
+
+    bool operator==(const QPointingDevice &other) const;
+
+protected:
+    QPointingDevice(QPointingDevicePrivate &d, QObject *parent = nullptr);
+
+    Q_DISABLE_COPY_MOVE(QPointingDevice)
+};
+
+Q_DECLARE_OPERATORS_FOR_FLAGS(QPointingDevice::PointerTypes)
+
+#ifndef QT_NO_DEBUG_STREAM
+Q_GUI_EXPORT QDebug operator<<(QDebug, const QPointingDevice *);
+#endif
+
+//typedef QPointingDevice QTouchDevice; // Qt 5 source compatibility if we need it? or could be "using"
+
+QT_END_NAMESPACE
+
+#endif // QPOINTINGDEVICE_H