From: Tang Haixiang <tanghaixiang@uniontech.com>
Date: Fri, 18 Jun 2021 06:29:01 +0000 (+0800)
Subject: xcb: Delete touch points without target windows
X-Git-Url: https://codereview.qt-project.org/gitweb?p=qt%2Fqtbase.git;a=commitdiff_plain;h=b0de19a831c4abdeddd062f973cc8f501aa5165d;hp=567340e1222d6be354b17ec66bf5f23066d4fa82

xcb: Delete touch points without target windows

When XCB_INPUT_TOUCH_BEGIN closes a popup, we then receive
XCB_INPUT_TOUCH_END, and cannot find a target window (because it's
destroyed). If we don't deliver it, we need to at least clear the
stored point from QPointingDevicePrivate::activePoints. Then when
we deliver the next touch press, m_fakeMouseSourcePointId also
needs to be reset.

It's now even more paramount that autotests (and real-world
touchscreens) must never omit any active touchpoint from a touch event.
If a point doesn't move, it must be included in the QTouchEvent, with
Stationary state. If not, QGuiApp::processTouchEvent() could generate
multiple TouchBegin events in a row, which gets other bits of logic
confused, here and there.

Fixes: QTBUG-94557
Fixes: QTBUG-98519
Fixes: QTBUG-102751
Fixes: QTBUG-103706
Change-Id: Ia95e410a2bb8bc7784aa5d296fac2b89e53a9f55
Reviewed-by: Shawn Rutledge <shawn.rutledge@qt.io>
(cherry picked from commit efc02f9cc301f98c77079adae026ffd07f50d5ab)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>
---

diff --git a/src/gui/kernel/qguiapplication.cpp b/src/gui/kernel/qguiapplication.cpp
--- a/src/gui/kernel/qguiapplication.cpp
+++ b/src/gui/kernel/qguiapplication.cpp
@@ -3061,7 +3061,7 @@ void QGuiApplicationPrivate::processTouc
                 QEvent::Type mouseEventType = QEvent::MouseMove;
                 Qt::MouseButton button = Qt::NoButton;
                 Qt::MouseButtons buttons = Qt::LeftButton;
-                if (eventType == QEvent::TouchBegin && m_fakeMouseSourcePointId < 0)
+                if (eventType == QEvent::TouchBegin || m_fakeMouseSourcePointId < 0)
                     m_fakeMouseSourcePointId = touchPoints.first().id();
                 for (const auto &touchPoint : touchPoints) {
                     if (touchPoint.id() == m_fakeMouseSourcePointId) {
diff --git a/src/plugins/platforms/xcb/qxcbconnection_xi2.cpp b/src/plugins/platforms/xcb/qxcbconnection_xi2.cpp
index 2fae965053fd..58cd79a7868a 100644
--- a/src/plugins/platforms/xcb/qxcbconnection_xi2.cpp
+++ b/src/plugins/platforms/xcb/qxcbconnection_xi2.cpp
@@ -782,8 +782,12 @@ void QXcbConnection::xi2HandleEvent(xcb_ge_event_t *event)
                         event->event_type, xiDeviceEvent->sequence, xiDeviceEvent->detail,
                         fixed1616ToReal(xiDeviceEvent->event_x), fixed1616ToReal(xiDeviceEvent->event_y),
                         fixed1616ToReal(xiDeviceEvent->root_x), fixed1616ToReal(xiDeviceEvent->root_y),xiDeviceEvent->event);
-            if (QXcbWindow *platformWindow = platformWindowFromId(xiDeviceEvent->event))
+            if (QXcbWindow *platformWindow = platformWindowFromId(xiDeviceEvent->event)) {
                 xi2ProcessTouch(xiDeviceEvent, platformWindow);
+            } else { // When the window cannot be matched, delete it from touchPoints
+                if (TouchDeviceData *dev = touchDeviceForId(xiDeviceEvent->sourceid))
+                    dev->touchPoints.remove((xiDeviceEvent->detail % INT_MAX));
+            }
             break;
         }
     } else if (xiEnterEvent && eventListener) {