Combine device and point id into 32 bit point id

This is second attempt of change cd26e66c2e8ddde06b5e22

This allows us to not have conflicts between the point ids between
different devices for QtQuick pointer handlers.

We do this in QtGui because we can then safely compare point ids from
QTouchEvent::TouchPoint and QQuickEventPoint.

(Point ids that QtQuick pointer handlers use will be based on the point
ids provided by QTouchEvent::TouchPoint::id)

[ChangeLog][QtGui][QTouchEvent][Important Behavior Changes]
Touch point ids are now unique even between different devices. As a
consequence of that, you cannot anymore assume that
QTouchEvent::TouchPoint::id has the same value as given by the native
platform nor the same value as given by synthesized touch points.

Change-Id: Iad2fd8c6a43ccc571a227a01134a1e8f829dfaf4
Reviewed-by: Frederik Gladhorn <frederik.gladhorn@qt.io>

6 files changed, 186 insertions, 15 deletions

diff --git a/src/gui/kernel/qguiapplication.cpp b/src/gui/kernel/qguiapplication.cpp
index d8457bc041..76386a30a0 100644
--- a/src/gui/kernel/qguiapplication.cpp
+++ b/src/gui/kernel/qguiapplication.cpp
@@ -84,6 +84,7 @@
 #include "private/qcursor_p.h"
 #include "private/qopenglcontext_p.h"
 #include "private/qinputdevicemanager_p.h"
+#include "private/qtouchdevice_p.h"
 
 #include "private/qdnd_p.h"
 #include <qpa/qplatformthemefactory_p.h>
@@ -1944,7 +1945,8 @@ void QGuiApplicationPrivate::processMouseEvent(QWindowSystemInterfacePrivate::Mo
         points << point;
 
         QEvent::Type type;
-        QList<QTouchEvent::TouchPoint> touchPoints = QWindowSystemInterfacePrivate::fromNativeTouchPoints(points, window, &type);
+        QList<QTouchEvent::TouchPoint> touchPoints =
+                QWindowSystemInterfacePrivate::fromNativeTouchPoints(points, window, QTouchDevicePrivate::get(m_fakeTouchDevice)->id, &type);
 
         QWindowSystemInterfacePrivate::TouchEvent fake(window, e->timestamp, type, m_fakeTouchDevice, touchPoints, e->modifiers);
         fake.flags |= QWindowSystemInterfacePrivate::WindowSystemEvent::Synthetic;
diff --git a/src/gui/kernel/qtouchdevice.h b/src/gui/kernel/qtouchdevice.h
index 0fb24e47bf..c98aa69236 100644
--- a/src/gui/kernel/qtouchdevice.h
+++ b/src/gui/kernel/qtouchdevice.h
@@ -87,6 +87,7 @@ public:
 
 private:
     QTouchDevicePrivate *d;
+    friend class QTouchDevicePrivate;
 };
 
 Q_DECLARE_OPERATORS_FOR_FLAGS(QTouchDevice::Capabilities)
diff --git a/src/gui/kernel/qtouchdevice_p.h b/src/gui/kernel/qtouchdevice_p.h
index 203d9fca74..18d2af46a7 100644
--- a/src/gui/kernel/qtouchdevice_p.h
+++ b/src/gui/kernel/qtouchdevice_p.h
@@ -64,16 +64,21 @@ public:
         : type(QTouchDevice::TouchScreen),
           caps(QTouchDevice::Position),
           maxTouchPoints(1)
-    { }
+    {
+        static quint8 nextId = 2;   // device 0 is not used, device 1 is for mouse device
+        id = nextId++;
+    }
 
     QTouchDevice::DeviceType type;
     QTouchDevice::Capabilities caps;
     QString name;
     int maxTouchPoints;
+    quint8 id;
 
     static void registerDevice(const QTouchDevice *dev);
     static void unregisterDevice(const QTouchDevice *dev);
     static bool isRegistered(const QTouchDevice *dev);
+    static QTouchDevicePrivate *get(QTouchDevice *q) { return q->d; }
 };
 
 QT_END_NAMESPACE
diff --git a/src/gui/kernel/qwindowsysteminterface.cpp b/src/gui/kernel/qwindowsysteminterface.cpp
index b799f75090..08aa625112 100644
--- a/src/gui/kernel/qwindowsysteminterface.cpp
+++ b/src/gui/kernel/qwindowsysteminterface.cpp
@@ -502,9 +502,41 @@ bool QWindowSystemInterface::isTouchDeviceRegistered(const QTouchDevice *device)
     return QTouchDevicePrivate::isRegistered(device);
 }
 
+static int g_nextPointId = 1;
+
+// map from device-independent point id (arbitrary) to "Qt point" ids
+typedef QMap<quint64, int> PointIdMap;
+Q_GLOBAL_STATIC(PointIdMap, g_pointIdMap)
+
+/*!
+    \internal
+    This function maps potentially arbitrary point ids \a pointId in the 32 bit
+    value space to start from 1 and increase incrementally for each touch point
+    held down. If all touch points are released it will reset the id back to 1
+    for the following touch point.
+
+    We can then assume that the touch points ids will never become too large,
+    and it will then put the device identifier \a deviceId in the upper 8 bits.
+    This leaves us with max 255 devices, and 16.7M taps without full release
+    before we run out of value space.
+*/
+static int acquireCombinedPointId(quint8 deviceId, int pointId)
+{
+    quint64 combinedId64 = (quint64(deviceId) << 32) + pointId;
+    auto it = g_pointIdMap->constFind(combinedId64);
+    int uid;
+    if (it == g_pointIdMap->constEnd()) {
+        uid = g_nextPointId++;
+        g_pointIdMap->insert(combinedId64, uid);
+    } else {
+        uid = *it;
+    }
+    return (deviceId << 24) + uid;
+}
+
 QList<QTouchEvent::TouchPoint>
     QWindowSystemInterfacePrivate::fromNativeTouchPoints(const QList<QWindowSystemInterface::TouchPoint> &points,
-                                                         const QWindow *window,
+                                                         const QWindow *window, quint8 deviceId,
                                                          QEvent::Type *type)
 {
     QList<QTouchEvent::TouchPoint> touchPoints;
@@ -515,7 +547,7 @@ QList<QTouchEvent::TouchPoint>
     QList<QWindowSystemInterface::TouchPoint>::const_iterator point = points.constBegin();
     QList<QWindowSystemInterface::TouchPoint>::const_iterator end = points.constEnd();
     while (point != end) {
-        p.setId(point->id);
+        p.setId(acquireCombinedPointId(deviceId, point->id));
         if (point->uniqueId >= 0)
             p.setUniqueId(point->uniqueId);
         p.setPressure(point->pressure);
@@ -548,6 +580,11 @@ QList<QTouchEvent::TouchPoint>
             *type = QEvent::TouchEnd;
     }
 
+    if (states == Qt::TouchPointReleased) {
+        g_nextPointId = 1;
+        g_pointIdMap->clear();
+    }
+
     return touchPoints;
 }
 
@@ -589,7 +626,8 @@ QT_DEFINE_QPA_EVENT_HANDLER(void, handleTouchEvent, QWindow *tlw, ulong timestam
         return;
 
     QEvent::Type type;
-    QList<QTouchEvent::TouchPoint> touchPoints = QWindowSystemInterfacePrivate::fromNativeTouchPoints(points, tlw, &type);
+    QList<QTouchEvent::TouchPoint> touchPoints =
+            QWindowSystemInterfacePrivate::fromNativeTouchPoints(points, tlw, QTouchDevicePrivate::get(device)->id, &type);
 
     QWindowSystemInterfacePrivate::TouchEvent *e =
             new QWindowSystemInterfacePrivate::TouchEvent(tlw, timestamp, type, device, touchPoints, mods);
diff --git a/src/gui/kernel/qwindowsysteminterface_p.h b/src/gui/kernel/qwindowsysteminterface_p.h
index 7c9b1f2852..ced2d01f73 100644
--- a/src/gui/kernel/qwindowsysteminterface_p.h
+++ b/src/gui/kernel/qwindowsysteminterface_p.h
@@ -508,7 +508,7 @@ public:
 
     static QList<QTouchEvent::TouchPoint>
         fromNativeTouchPoints(const QList<QWindowSystemInterface::TouchPoint> &points,
-                              const QWindow *window, QEvent::Type *type = Q_NULLPTR);
+                              const QWindow *window, quint8 deviceId, QEvent::Type *type = Q_NULLPTR);
     static QList<QWindowSystemInterface::TouchPoint>
         toNativeTouchPoints(const QList<QTouchEvent::TouchPoint>& pointList,
                             const QWindow *window);
diff --git a/tests/auto/gui/kernel/qtouchevent/tst_qtouchevent.cpp b/tests/auto/gui/kernel/qtouchevent/tst_qtouchevent.cpp
index e6fd67e3a8..a3de9ee5b5 100644
--- a/tests/auto/gui/kernel/qtouchevent/tst_qtouchevent.cpp
+++ b/tests/auto/gui/kernel/qtouchevent/tst_qtouchevent.cpp
@@ -36,6 +36,7 @@
 #include <qpa/qwindowsysteminterface.h>
 #include <qpa/qwindowsysteminterface_p.h>
 #include <private/qhighdpiscaling_p.h>
+#include <private/qtouchdevice_p.h>
 
 class tst_QTouchEventWidget : public QWidget
 {
@@ -199,6 +200,7 @@ private slots:
     void touchBeginPropagatesWhenIgnored();
     void touchUpdateAndEndNeverPropagate();
     void basicRawEventTranslation();
+    void basicRawEventTranslationOfIds();
     void multiPointRawEventTranslationOnTouchScreen();
     void multiPointRawEventTranslationOnTouchPad();
     void deleteInEventHandler();
@@ -602,7 +604,8 @@ void tst_QTouchEvent::basicRawEventTranslation()
     QCOMPARE(touchWidget.touchBeginPoints.count(), 1);
     QCOMPARE(touchWidget.timestamp, timestamp);
     QTouchEvent::TouchPoint touchBeginPoint = touchWidget.touchBeginPoints.first();
-    QCOMPARE(touchBeginPoint.id(), rawTouchPoint.id());
+    const int touchPointId = (QTouchDevicePrivate::get(touchScreenDevice)->id << 24) + 1;
+    QCOMPARE(touchBeginPoint.id(), touchPointId);
     QCOMPARE(touchBeginPoint.state(), rawTouchPoint.state());
     QCOMPARE(touchBeginPoint.pos(), pos);
     QCOMPARE(touchBeginPoint.startPos(), pos);
@@ -637,7 +640,7 @@ void tst_QTouchEvent::basicRawEventTranslation()
     QVERIFY(!touchWidget.seenTouchEnd);
     QCOMPARE(touchWidget.touchUpdatePoints.count(), 1);
     QTouchEvent::TouchPoint touchUpdatePoint = touchWidget.touchUpdatePoints.first();
-    QCOMPARE(touchUpdatePoint.id(), rawTouchPoint.id());
+    QCOMPARE(touchUpdatePoint.id(), touchPointId);
     QCOMPARE(touchUpdatePoint.state(), rawTouchPoint.state());
     QCOMPARE(touchUpdatePoint.pos(), pos + delta);
     QCOMPARE(touchUpdatePoint.startPos(), pos);
@@ -669,7 +672,7 @@ void tst_QTouchEvent::basicRawEventTranslation()
     QVERIFY(touchWidget.seenTouchEnd);
     QCOMPARE(touchWidget.touchEndPoints.count(), 1);
     QTouchEvent::TouchPoint touchEndPoint = touchWidget.touchEndPoints.first();
-    QCOMPARE(touchEndPoint.id(), rawTouchPoint.id());
+    QCOMPARE(touchEndPoint.id(), touchPointId);
     QCOMPARE(touchEndPoint.state(), rawTouchPoint.state());
     QCOMPARE(touchEndPoint.pos(), pos + delta + delta);
     QCOMPARE(touchEndPoint.startPos(), pos);
@@ -745,9 +748,11 @@ void tst_QTouchEvent::multiPointRawEventTranslationOnTouchScreen()
     QVERIFY(!rightWidget.seenTouchEnd);
     QCOMPARE(leftWidget.touchBeginPoints.count(), 1);
     QCOMPARE(rightWidget.touchBeginPoints.count(), 1);
+    const int touchPointId0 = (QTouchDevicePrivate::get(touchScreenDevice)->id << 24) + 1;
+    const int touchPointId1 = touchPointId0 + 1;
     {
         QTouchEvent::TouchPoint leftTouchPoint = leftWidget.touchBeginPoints.first();
-        QCOMPARE(leftTouchPoint.id(), rawTouchPoints[0].id());
+        QCOMPARE(leftTouchPoint.id(), touchPointId0);
         QCOMPARE(leftTouchPoint.state(), rawTouchPoints[0].state());
         QCOMPARE(leftTouchPoint.pos(), leftPos);
         QCOMPARE(leftTouchPoint.startPos(), leftPos);
@@ -767,7 +772,7 @@ void tst_QTouchEvent::multiPointRawEventTranslationOnTouchScreen()
         QCOMPARE(leftTouchPoint.pressure(), qreal(1.));
 
         QTouchEvent::TouchPoint rightTouchPoint = rightWidget.touchBeginPoints.first();
-        QCOMPARE(rightTouchPoint.id(), rawTouchPoints[1].id());
+        QCOMPARE(rightTouchPoint.id(), touchPointId1);
         QCOMPARE(rightTouchPoint.state(), rawTouchPoints[1].state());
         QCOMPARE(rightTouchPoint.pos(), rightPos);
         QCOMPARE(rightTouchPoint.startPos(), rightPos);
@@ -811,7 +816,7 @@ void tst_QTouchEvent::multiPointRawEventTranslationOnTouchScreen()
     QCOMPARE(rightWidget.touchUpdatePoints.count(), 1);
     {
         QTouchEvent::TouchPoint leftTouchPoint = leftWidget.touchUpdatePoints.first();
-        QCOMPARE(leftTouchPoint.id(), rawTouchPoints[0].id());
+        QCOMPARE(leftTouchPoint.id(), touchPointId0);
         QCOMPARE(leftTouchPoint.state(), rawTouchPoints[0].state());
         QCOMPARE(leftTouchPoint.pos(), QPointF(leftWidget.mapFromParent(centerPos.toPoint())));
         QCOMPARE(leftTouchPoint.startPos(), leftPos);
@@ -831,7 +836,7 @@ void tst_QTouchEvent::multiPointRawEventTranslationOnTouchScreen()
         QCOMPARE(leftTouchPoint.pressure(), qreal(1.));
 
         QTouchEvent::TouchPoint rightTouchPoint = rightWidget.touchUpdatePoints.first();
-        QCOMPARE(rightTouchPoint.id(), rawTouchPoints[1].id());
+        QCOMPARE(rightTouchPoint.id(), touchPointId1);
         QCOMPARE(rightTouchPoint.state(), rawTouchPoints[1].state());
         QCOMPARE(rightTouchPoint.pos(), QPointF(rightWidget.mapFromParent(centerPos.toPoint())));
         QCOMPARE(rightTouchPoint.startPos(), rightPos);
@@ -875,7 +880,7 @@ void tst_QTouchEvent::multiPointRawEventTranslationOnTouchScreen()
     QCOMPARE(rightWidget.touchEndPoints.count(), 1);
     {
         QTouchEvent::TouchPoint leftTouchPoint = leftWidget.touchEndPoints.first();
-        QCOMPARE(leftTouchPoint.id(), rawTouchPoints[0].id());
+        QCOMPARE(leftTouchPoint.id(), touchPointId0);
         QCOMPARE(leftTouchPoint.state(), rawTouchPoints[0].state());
         QCOMPARE(leftTouchPoint.pos(), QPointF(leftWidget.mapFromParent(centerPos.toPoint())));
         QCOMPARE(leftTouchPoint.startPos(), leftPos);
@@ -895,7 +900,7 @@ void tst_QTouchEvent::multiPointRawEventTranslationOnTouchScreen()
         QCOMPARE(leftTouchPoint.pressure(), qreal(0.));
 
         QTouchEvent::TouchPoint rightTouchPoint = rightWidget.touchEndPoints.first();
-        QCOMPARE(rightTouchPoint.id(), rawTouchPoints[1].id());
+        QCOMPARE(rightTouchPoint.id(), touchPointId1);
         QCOMPARE(rightTouchPoint.state(), rawTouchPoints[1].state());
         QCOMPARE(rightTouchPoint.pos(), QPointF(rightWidget.mapFromParent(centerPos.toPoint())));
         QCOMPARE(rightTouchPoint.startPos(), rightPos);
@@ -1145,6 +1150,126 @@ void tst_QTouchEvent::multiPointRawEventTranslationOnTouchPad()
     }
 }
 
+void tst_QTouchEvent::basicRawEventTranslationOfIds()
+{
+    if (!QGuiApplication::platformName().compare(QLatin1String("wayland"), Qt::CaseInsensitive))
+        QSKIP("Wayland: This fails. Figure out why.");
+
+    tst_QTouchEventWidget touchWidget;
+    touchWidget.setWindowTitle(QTest::currentTestFunction());
+    touchWidget.setAttribute(Qt::WA_AcceptTouchEvents);
+    touchWidget.setGeometry(100, 100, 400, 300);
+    touchWidget.show();
+    QVERIFY(QTest::qWaitForWindowActive(&touchWidget));
+
+    QVarLengthArray<QPointF, 2> pos;
+    QVarLengthArray<QPointF, 2> screenPos;
+    for (int i = 0; i < 2; ++i) {
+        pos << touchWidget.rect().center() + QPointF(20*i, 20*i);
+        screenPos << touchWidget.mapToGlobal(pos[i].toPoint());
+    }
+    QPointF delta(10, 10);
+    QRectF screenGeometry = QApplication::desktop()->screenGeometry(&touchWidget);
+
+    QVector<QPointF> rawPosList;
+    rawPosList << QPointF(12, 34) << QPointF(56, 78);
+
+    QList<QTouchEvent::TouchPoint> rawTouchPoints;
+
+    // Press both points, this should be translated to a TouchBegin
+    for (int i = 0; i < 2; ++i) {
+        QTouchEvent::TouchPoint rawTouchPoint;
+        rawTouchPoint.setId(i);
+        rawTouchPoint.setState(Qt::TouchPointPressed);
+        rawTouchPoint.setScreenPos(screenPos[i]);
+        rawTouchPoint.setNormalizedPos(normalized(rawTouchPoint.pos(), screenGeometry));
+        rawTouchPoint.setRawScreenPositions(rawPosList);
+        rawTouchPoints << rawTouchPoint;
+    }
+    QTouchEvent::TouchPoint &p0 = rawTouchPoints[0];
+    QTouchEvent::TouchPoint &p1 = rawTouchPoints[1];
+
+    const ulong timestamp = 1234;
+    QWindow *window = touchWidget.windowHandle();
+    QList<QWindowSystemInterface::TouchPoint> nativeTouchPoints =
+        QWindowSystemInterfacePrivate::toNativeTouchPoints(rawTouchPoints, window);
+    QWindowSystemInterface::handleTouchEvent(window, timestamp, touchScreenDevice, nativeTouchPoints);
+    QCoreApplication::processEvents();
+    QVERIFY(touchWidget.seenTouchBegin);
+    QVERIFY(!touchWidget.seenTouchUpdate);
+    QVERIFY(!touchWidget.seenTouchEnd);
+    QCOMPARE(touchWidget.touchBeginPoints.count(), 2);
+
+    const int initialTouchPointId = (QTouchDevicePrivate::get(touchScreenDevice)->id << 24) + 1;
+
+    for (int i = 0; i < touchWidget.touchBeginPoints.count(); ++i) {
+        QTouchEvent::TouchPoint touchBeginPoint = touchWidget.touchBeginPoints.at(i);
+        QCOMPARE(touchBeginPoint.id(), initialTouchPointId + i);
+        QCOMPARE(touchBeginPoint.state(), rawTouchPoints[i].state());
+    }
+
+    // moving the point should translate to TouchUpdate
+    for (int i = 0; i < rawTouchPoints.count(); ++i) {
+        QTouchEvent::TouchPoint &p = rawTouchPoints[i];
+        p.setState(Qt::TouchPointMoved);
+        p.setScreenPos(p.screenPos() + delta);
+        p.setNormalizedPos(normalized(p.pos(), screenGeometry));
+    }
+    nativeTouchPoints =
+        QWindowSystemInterfacePrivate::toNativeTouchPoints(rawTouchPoints, window);
+    QWindowSystemInterface::handleTouchEvent(window, 0, touchScreenDevice, nativeTouchPoints);
+    QCoreApplication::processEvents();
+    QVERIFY(touchWidget.seenTouchBegin);
+    QVERIFY(touchWidget.seenTouchUpdate);
+    QVERIFY(!touchWidget.seenTouchEnd);
+    QCOMPARE(touchWidget.touchUpdatePoints.count(), 2);
+    QCOMPARE(touchWidget.touchUpdatePoints.at(0).id(), initialTouchPointId);
+    QCOMPARE(touchWidget.touchUpdatePoints.at(1).id(), initialTouchPointId + 1);
+
+    // release last point
+    p0.setState(Qt::TouchPointStationary);
+    p1.setState(Qt::TouchPointReleased);
+
+    nativeTouchPoints =
+        QWindowSystemInterfacePrivate::toNativeTouchPoints(rawTouchPoints, window);
+    QWindowSystemInterface::handleTouchEvent(window, 0, touchScreenDevice, nativeTouchPoints);
+    QCoreApplication::processEvents();
+    QVERIFY(touchWidget.seenTouchBegin);
+    QVERIFY(touchWidget.seenTouchUpdate);
+    QVERIFY(!touchWidget.seenTouchEnd);
+    QCOMPARE(touchWidget.touchUpdatePoints.count(), 2);
+    QCOMPARE(touchWidget.touchUpdatePoints[0].id(), initialTouchPointId);
+    QCOMPARE(touchWidget.touchUpdatePoints[1].id(), initialTouchPointId + 1);
+
+    // Press last point again, id should increase
+    p1.setState(Qt::TouchPointPressed);
+    p1.setId(42);   // new id
+    nativeTouchPoints =
+        QWindowSystemInterfacePrivate::toNativeTouchPoints(rawTouchPoints, window);
+    QWindowSystemInterface::handleTouchEvent(window, 0, touchScreenDevice, nativeTouchPoints);
+    QCoreApplication::processEvents();
+    QVERIFY(touchWidget.seenTouchBegin);
+    QVERIFY(touchWidget.seenTouchUpdate);
+    QVERIFY(!touchWidget.seenTouchEnd);
+    QCOMPARE(touchWidget.touchUpdatePoints.count(), 2);
+    QCOMPARE(touchWidget.touchUpdatePoints[0].id(), initialTouchPointId);
+    QCOMPARE(touchWidget.touchUpdatePoints[1].id(), initialTouchPointId + 2);
+
+    // release everything
+    p0.setState(Qt::TouchPointReleased);
+    p1.setState(Qt::TouchPointReleased);
+    nativeTouchPoints =
+        QWindowSystemInterfacePrivate::toNativeTouchPoints(rawTouchPoints, window);
+    QWindowSystemInterface::handleTouchEvent(window, 0, touchScreenDevice, nativeTouchPoints);
+    QCoreApplication::processEvents();
+    QVERIFY(touchWidget.seenTouchBegin);
+    QVERIFY(touchWidget.seenTouchUpdate);
+    QVERIFY(touchWidget.seenTouchEnd);
+    QCOMPARE(touchWidget.touchUpdatePoints.count(), 2);
+    QCOMPARE(touchWidget.touchUpdatePoints[0].id(), initialTouchPointId);
+    QCOMPARE(touchWidget.touchUpdatePoints[1].id(), initialTouchPointId + 2);
+}
+
 void tst_QTouchEvent::deleteInEventHandler()
 {
     if (!QGuiApplication::platformName().compare(QLatin1String("wayland"), Qt::CaseInsensitive))