make the QTouchDevice available in each QNativeGestureEvent

QtQuick is beginning to have a use for this, to distinguish native
gestures which come from actual trackpad rather than from the "core pointer".
It might as well use a real device ID instead of making one up,
as it has to do for the core pointer.

So far on macOS, the device ID isn't a real one; but that can be fixed,
as the qCDebug lines demonstrate (different trackpads have different IDs).

Change-Id: I5841deb1c4cc0b77a3b1df70904f70b3d2d71853
Reviewed-by: Shawn Rutledge <shawn.rutledge@qt.io>
Reviewed-by: Jan Arve Sæther <jan-arve.saether@qt.io>

1 files changed, 9 insertions, 0 deletions

diff --git a/src/gui/kernel/qtouchdevice.cpp b/src/gui/kernel/qtouchdevice.cpp
index 0f13412fb1..511e92566e 100644
--- a/src/gui/kernel/qtouchdevice.cpp
+++ b/src/gui/kernel/qtouchdevice.cpp
@@ -235,6 +235,15 @@ bool QTouchDevicePrivate::isRegistered(const QTouchDevice *dev)
     return deviceList()->contains(dev);
 }
 
+const QTouchDevice *QTouchDevicePrivate::deviceById(quint8 id)
+{
+    QMutexLocker locker(&devicesMutex);
+    for (const QTouchDevice *dev : *deviceList())
+        if (QTouchDevicePrivate::get(const_cast<QTouchDevice *>(dev))->id == id)
+            return dev;
+    return nullptr;
+}
+
 /*!
   \internal
   */