Move event delivery from QQWindow to QQuickDeliveryAgent

QQuickWindow owns QQuickRootItem which owns QQuickDeliveryAgent, so
for every window there's an object responsible for event delivery,
while the window itself is mainly responsible for rendering (separation
of concerns).  However, QQuickRootItem and QQuickDeliveryAgent can now
be used in cases where the scene doesn't directly belong to a window,
such as when a Qt Quick sub-scene is mapped somewhere into a Qt Quick 3D
scene.  In that case, we must remember which delivery agent was in use
at the time when a QEventPoint is grabbed and deliver subsequent updates
via the same DA.  There's also a QQuickDeliveryAgent::Transform
abstraction which subscene-management code (such as QQuick3DViewport)
can implement, to provide a formula to map the window's scene
coordinates to subscene coordinates; if defined, it will be used
during delivery of subsequent updates to existing grabbers.

Task-number: QTBUG-84870
Change-Id: I70b433f7ebb05d2e60214ff3192e05da0aa84a42
Reviewed-by: Andy Nichols <andy.nichols@qt.io>

1 files changed, 209 insertions, 0 deletions

diff --git a/src/quick/util/qquickdeliveryagent_p_p.h b/src/quick/util/qquickdeliveryagent_p_p.h
new file mode 100644
index 0000000000..123eea1191
--- /dev/null
+++ b/src/quick/util/qquickdeliveryagent_p_p.h
@@ -0,0 +1,209 @@
+/****************************************************************************
+**
+** Copyright (C) 2021 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the QtQuick 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
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** 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 QQUICKDELIVERYAGENT_P_P_H
+#define QQUICKDELIVERYAGENT_P_P_H
+
+//
+//  W A R N I N G
+//  -------------
+//
+// This file is not part of the Qt API.  It exists purely as an
+// implementation detail.  This header file may change from version to
+// version without notice, or even be removed.
+//
+// We mean it.
+//
+
+#include <QtQuick/private/qquickdeliveryagent_p.h>
+#include <QtGui/qevent.h>
+#include <QtCore/qstack.h>
+
+#include <private/qevent_p.h>
+#include <private/qpointingdevice_p.h>
+#include <private/qobject_p.h>
+
+QT_BEGIN_NAMESPACE
+
+class QQuickDragGrabber;
+class QQuickItem;
+class QQuickPointerHandler;
+class QQuickWindow;
+
+/*! \internal
+    Extra device-specific data to be stored in QInputDevicePrivate::qqExtra
+*/
+struct QQuickPointingDeviceExtra {
+    // used in QQuickPointerHandlerPrivate::deviceDeliveryTargets
+    QVector<QObject *> deliveryTargets;
+    // memory of which agent was delivering when each QEventPoint was grabbed
+    // TODO maybe add QEventPointPrivate::qqExtra, or sth in QPointingDevicePrivate::EventPointData
+    QFlatMap<int, QQuickDeliveryAgent*> grabbedEventPointDeliveryAgents;
+};
+
+class Q_QUICK_PRIVATE_EXPORT QQuickDeliveryAgentPrivate : public QObjectPrivate
+{
+    Q_DECLARE_PUBLIC(QQuickDeliveryAgent)
+public:
+    QQuickDeliveryAgentPrivate(QQuickItem *root);
+    ~QQuickDeliveryAgentPrivate();
+
+    QQuickItem *rootItem = nullptr;
+
+    QQuickItem *activeFocusItem = nullptr;
+
+    void deliverKeyEvent(QKeyEvent *e);
+
+    enum FocusOption {
+        DontChangeFocusProperty = 0x01,
+        DontChangeSubFocusItem  = 0x02
+    };
+    Q_DECLARE_FLAGS(FocusOptions, FocusOption)
+
+    void setFocusInScope(QQuickItem *scope, QQuickItem *item, Qt::FocusReason reason, FocusOptions = { });
+    void clearFocusInScope(QQuickItem *scope, QQuickItem *item, Qt::FocusReason reason, FocusOptions = { });
+    static void notifyFocusChangesRecur(QQuickItem **item, int remaining);
+    void clearFocusObject();
+    void updateFocusItemTransform();
+
+    // Keeps track of the item currently receiving mouse events
+#if QT_CONFIG(quick_draganddrop)
+    QQuickDragGrabber *dragGrabber = nullptr;
+#endif
+    QQuickItem *lastUngrabbed = nullptr;
+    QStack<QPointerEvent *> eventsInDelivery;
+    QList<QPointer<QQuickItem>> hoverItems;
+    QVector<QQuickItem *> hasFiltered; // during event delivery to a single receiver, the filtering parents for which childMouseEventFilter was already called
+    QVector<QQuickItem *> skipDelivery; // during delivery of one event to all receivers, Items to which we know delivery is no longer necessary
+
+    QScopedPointer<QMutableTouchEvent> delayedTouch;
+    QList<const QPointingDevice *> knownPointingDevices;
+
+    uint lastWheelEventAccepted = 0;
+    bool allowChildEventFiltering = true;
+    bool allowDoubleClick = true;
+    bool frameSynchronousHoverEnabled = true;
+
+    bool isSubsceneAgent = false;
+
+    Qt::FocusReason lastFocusReason = Qt::OtherFocusReason;
+    int pointerEventRecursionGuard = 0;
+
+    int touchMouseId = -1; // only for obsolete stuff like QQuickItem::grabMouse()
+    // TODO get rid of these
+    const QPointingDevice *touchMouseDevice = nullptr;
+    ulong touchMousePressTimestamp = 0;
+    QPoint touchMousePressPos;      // in screen coordinates
+
+    QQuickDeliveryAgent::Transform *sceneTransform = nullptr;
+
+    bool isDeliveringTouchAsMouse() const { return touchMouseId != -1 && touchMouseDevice; }
+    void cancelTouchMouseSynthesis();
+
+    bool checkIfDoubleTapped(ulong newPressEventTimestamp, QPoint newPressPos);
+    QPointingDevicePrivate::EventPointData *mousePointData();
+    QPointerEvent *eventInDelivery() const;
+
+    // Mouse positions are saved in widget coordinates
+    QPointF lastMousePosition;
+    bool deliverTouchAsMouse(QQuickItem *item, QTouchEvent *pointerEvent);
+    void translateTouchEvent(QTouchEvent *touchEvent);
+    void removeGrabber(QQuickItem *grabber, bool mouse = true, bool touch = true, bool cancel = false);
+    void onGrabChanged(QObject *grabber, QPointingDevice::GrabTransition transition, const QPointerEvent *event, const QEventPoint &point);
+    static QPointerEvent *clonePointerEvent(QPointerEvent *event, std::optional<QPointF> transformedLocalPos = std::nullopt);
+    void deliverToPassiveGrabbers(const QVector<QPointer<QObject> > &passiveGrabbers, QPointerEvent *pointerEvent);
+    bool sendFilteredMouseEvent(QEvent *event, QQuickItem *receiver, QQuickItem *filteringParent);
+    bool sendFilteredPointerEvent(QPointerEvent *event, QQuickItem *receiver, QQuickItem *filteringParent = nullptr);
+    bool sendFilteredPointerEventImpl(QPointerEvent *event, QQuickItem *receiver, QQuickItem *filteringParent);
+    bool deliverSinglePointEventUntilAccepted(QPointerEvent *);
+
+    // entry point of events to the window
+    void handleTouchEvent(QTouchEvent *);
+    void handleMouseEvent(QMouseEvent *);
+    bool compressTouchEvent(QTouchEvent *);
+    void flushFrameSynchronousEvents(QQuickWindow *win);
+    void deliverDelayedTouchEvent();
+    void handleWindowDeactivate(QQuickWindow *win);
+
+    // utility functions that used to be in QQuickPointerEvent et al.
+    bool allUpdatedPointsAccepted(const QPointerEvent *ev);
+    static void localizePointerEvent(QPointerEvent *ev, const QQuickItem *dest);
+    QList<QObject *> exclusiveGrabbers(QPointerEvent *ev);
+    static bool anyPointGrabbed(const QPointerEvent *ev);
+    static bool isMouseEvent(const QPointerEvent *ev);
+    static bool isTouchEvent(const QPointerEvent *ev);
+    static bool isTabletEvent(const QPointerEvent *ev);
+    static QQuickPointingDeviceExtra *deviceExtra(const QInputDevice *device);
+
+    // delivery of pointer events:
+    void touchToMouseEvent(QEvent::Type type, const QEventPoint &p, const QTouchEvent *touchEvent, QMutableSinglePointEvent *mouseEvent);
+    void ensureDeviceConnected(const QPointingDevice *dev);
+    void deliverPointerEvent(QPointerEvent *);
+    bool deliverTouchCancelEvent(QTouchEvent *);
+    bool deliverPressOrReleaseEvent(QPointerEvent *, bool handlersOnly = false);
+    void deliverUpdatedPoints(QPointerEvent *event);
+    void deliverMatchingPointsToItem(QQuickItem *item, bool isGrabber, QPointerEvent *pointerEvent, bool handlersOnly = false);
+
+    QVector<QQuickItem *> pointerTargets(QQuickItem *, const QPointerEvent *event, const QEventPoint &point,
+                                         bool checkMouseButtons, bool checkAcceptsTouch) const;
+    QVector<QQuickItem *> mergePointerTargets(const QVector<QQuickItem *> &list1, const QVector<QQuickItem *> &list2) const;
+
+    // hover delivery
+    bool deliverHoverEvent(QQuickItem *, const QPointF &scenePos, const QPointF &lastScenePos, Qt::KeyboardModifiers modifiers, ulong timestamp, bool &accepted);
+    bool sendHoverEvent(QEvent::Type, QQuickItem *, const QPointF &scenePos, const QPointF &lastScenePos,
+                        Qt::KeyboardModifiers modifiers, ulong timestamp, bool accepted);
+    bool clearHover(ulong timestamp = 0);
+
+#if QT_CONFIG(quick_draganddrop)
+    void deliverDragEvent(QQuickDragGrabber *, QEvent *);
+    bool deliverDragEvent(QQuickDragGrabber *, QQuickItem *, QDragMoveEvent *, QVarLengthArray<QQuickItem*, 64> *currentGrabItems = nullptr);
+#endif
+
+    static bool dragOverThreshold(qreal d, Qt::Axis axis, QMouseEvent *event, int startDragThreshold = -1);
+
+    static bool dragOverThreshold(qreal d, Qt::Axis axis, const QEventPoint &tp, int startDragThreshold = -1);
+
+    static bool dragOverThreshold(QVector2D delta);
+};
+
+Q_DECLARE_OPERATORS_FOR_FLAGS(QQuickDeliveryAgentPrivate::FocusOptions)
+
+QT_END_NAMESPACE
+
+#endif // QQUICKDELIVERYAGENT_P_P_H