Add popup support to QWaylandQuickCompositor with the wl shell.

When the shell surface emits the QWaylandShell::setPopup signal the
QWaylandQuickWlShellSurfaceItem will move it self into its popup-parent,
and also remove all transforms (rotation, scaling, etc.), our new
parent already have the same transforms set.

During the time a popup is active it installs a filter
which handles the closing of popups if the user clicks
outside the popup. This requires that the background item of the
compositor accepts mouse press.

Change-Id: I3e4c3c8728795d4b38a30a9bce178dc315643de2
Reviewed-by: Johan Helsing <johan.helsing@qt.io>
Reviewed-by: Paul Olav Tvete <paul.tvete@theqtcompany.com>
Reviewed-by: Giulio Camuffo <giulio.camuffo@kdab.com>

4 files changed, 164 insertions, 0 deletions

diff --git a/src/compositor/extensions/qwaylandquickwlshellsurfaceitem.cpp b/src/compositor/extensions/qwaylandquickwlshellsurfaceitem.cpp
index 21b5c75a..393a054c 100644
--- a/src/compositor/extensions/qwaylandquickwlshellsurfaceitem.cpp
+++ b/src/compositor/extensions/qwaylandquickwlshellsurfaceitem.cpp
@@ -39,6 +39,7 @@
 
 #include <QtWaylandCompositor/QWaylandCompositor>
 #include <QtWaylandCompositor/QWaylandInputDevice>
+#include <QGuiApplication>
 
 QT_BEGIN_NAMESPACE
 
@@ -108,11 +109,15 @@ void QWaylandQuickWlShellSurfaceItem::setShellSurface(QWaylandWlShellSurface *sh
     if (d->shellSurface) {
         disconnect(d->shellSurface, &QWaylandWlShellSurface::startMove, this, &QWaylandQuickWlShellSurfaceItem::handleStartMove);
         disconnect(d->shellSurface, &QWaylandWlShellSurface::startResize, this, &QWaylandQuickWlShellSurfaceItem::handleStartResize);
+        disconnect(d->shellSurface, &QWaylandWlShellSurface::setPopup, this, &QWaylandQuickWlShellSurfaceItem::handleSetPopup);
+        disconnect(d->shellSurface, &QWaylandWlShellSurface::destroyed, this, &QWaylandQuickWlShellSurfaceItem::handleShellSurfaceDestroyed);
     }
     d->shellSurface = shellSurface;
     if (d->shellSurface) {
         connect(d->shellSurface, &QWaylandWlShellSurface::startMove, this, &QWaylandQuickWlShellSurfaceItem::handleStartMove);
         connect(d->shellSurface, &QWaylandWlShellSurface::startResize, this, &QWaylandQuickWlShellSurfaceItem::handleStartResize);
+        connect(d->shellSurface, &QWaylandWlShellSurface::setPopup, this, &QWaylandQuickWlShellSurfaceItem::handleSetPopup);
+        connect(d->shellSurface, &QWaylandWlShellSurface::destroyed, this, &QWaylandQuickWlShellSurfaceItem::handleShellSurfaceDestroyed);
     }
     setSurface(shellSurface ? shellSurface->surface() : nullptr);
     emit shellSurfaceChanged();
@@ -166,6 +171,48 @@ void QWaylandQuickWlShellSurfaceItem::handleStartResize(QWaylandInputDevice *inp
 /*!
  * \internal
  */
+void QWaylandQuickWlShellSurfaceItem::handleSetPopup(QWaylandInputDevice *inputDevice, QWaylandSurface *parent, const QPoint &relativeToParent)
+{
+    Q_UNUSED(inputDevice);
+    Q_D(QWaylandQuickWlShellSurfaceItem);
+
+    QWaylandQuickWlShellSurfaceItem* parentItem = qobject_cast<QWaylandQuickWlShellSurfaceItem*>(parent->views().first()->renderObject());
+    if (parentItem) {
+        // Clear all the transforms for this ShellSurfaceItem. They are not
+        // applicable when the item becomes a child to a surface that has its
+        // own transforms. Otherwise the transforms would be applied twice.
+        QQmlListProperty<QQuickTransform> t = transform();
+        t.clear(&t);
+        setRotation(0);
+        setScale(1.0);
+        setX(relativeToParent.x());
+        setY(relativeToParent.y());
+        setParentItem(parentItem);
+    }
+
+    d->setIsPopup(true);
+}
+
+/*!
+ * \internal
+ */
+void QWaylandQuickWlShellSurfaceItem::handleShellSurfaceDestroyed() {
+    Q_D(QWaylandQuickWlShellSurfaceItem);
+    d->setIsPopup(false);
+    d->shellSurface = NULL;
+}
+
+void QWaylandQuickWlShellSurfaceItem::handleSurfaceUnmapped()
+{
+    Q_D(QWaylandQuickWlShellSurfaceItem);
+    if (!d->shellSurface || !d->shellSurface->surface()->size().isEmpty())
+        return;
+    d->setIsPopup(false);
+}
+
+/*!
+ * \internal
+ */
 void QWaylandQuickWlShellSurfaceItem::adjustOffsetForNextFrame(const QPointF &offset)
 {
     Q_D(QWaylandQuickWlShellSurfaceItem);
@@ -231,4 +278,101 @@ void QWaylandQuickWlShellSurfaceItem::surfaceChangedEvent(QWaylandSurface *newSu
         connect(newSurface, &QWaylandSurface::offsetForNextFrame, this, &QWaylandQuickWlShellSurfaceItem::adjustOffsetForNextFrame);
 }
 
+QVector<QWaylandWlShellSurface*> QWaylandQuickWlShellSurfaceItemPrivate::popupShellSurfaces;
+bool QWaylandQuickWlShellSurfaceItemPrivate::eventFilterInstalled = false;
+bool QWaylandQuickWlShellSurfaceItemPrivate::waitForRelease = false;
+
+/*!
+ * \internal
+ */
+void QWaylandQuickWlShellSurfaceItemPrivate::closePopups()
+{
+    if (!popupShellSurfaces.isEmpty()) {
+        Q_FOREACH (QWaylandWlShellSurface* shellSurface, popupShellSurfaces) {
+            shellSurface->sendPopupDone();
+        }
+        popupShellSurfaces.clear();
+    }
+}
+
+bool QWaylandQuickWlShellSurfaceItem::eventFilter(QObject *receiver, QEvent *e)
+{
+    Q_D(QWaylandQuickWlShellSurfaceItem);
+    if (e->type() == QEvent::MouseButtonPress || e->type() == QEvent::MouseButtonRelease) {
+        QQuickItem *item = qobject_cast<QQuickItem*>(receiver);
+        if (!item)
+            return false;
+
+        QMouseEvent *event = static_cast<QMouseEvent*>(e);
+        QWaylandQuickWlShellSurfaceItem *shellSurfaceItem = qobject_cast<QWaylandQuickWlShellSurfaceItem*>(item);
+        bool press = event->type() == QEvent::MouseButtonPress;
+        bool finalRelease = (event->type() == QEvent::MouseButtonRelease) && (event->buttons() == Qt::NoButton);
+        bool popupClient = shellSurfaceItem && shellSurfaceItem->shellSurface()->surface()->client() == shellSurface()->surface()->client();
+
+        if (d->waitForRelease) {
+            // We are eating events until all mouse buttons are released
+            if (finalRelease) {
+                d->waitForRelease = false;
+                d->setFilterEnabled(false);
+            }
+            return true;
+        }
+
+        if (press && !popupClient) {
+            // The user clicked outside the active popup's client. The popups should
+            // be closed, but the event filter will stay to catch the release-
+            // event before removing itself.
+            d->waitForRelease = true;
+            d->closePopups();
+            return true;
+        } else if (press) {
+            // There is a surface belonging to this client at this coordinate, so we can
+            // remove the event filter and let the normal event handler handle
+            // this event.
+            d->setFilterEnabled(false);
+        }
+    }
+
+    return false;
+}
+
+void QWaylandQuickWlShellSurfaceItemPrivate::setIsPopup(bool popup)
+{
+    Q_Q(QWaylandQuickWlShellSurfaceItem);
+    isPopup = popup;
+    if (popup) {
+        if (!eventFilterInstalled)
+           setFilterEnabled(true);
+
+        if (!popupShellSurfaces.contains(shellSurface)) {
+            popupShellSurfaces.append(shellSurface);
+            QObject::connect(shellSurface->surface(), &QWaylandSurface::mappedChanged,
+                             q, &QWaylandQuickWlShellSurfaceItem::handleSurfaceUnmapped);
+        }
+    } else {
+        if (shellSurface) {
+            popupShellSurfaces.removeOne(shellSurface);
+            QObject::disconnect(shellSurface->surface(), &QWaylandSurface::mappedChanged,
+                             q, &QWaylandQuickWlShellSurfaceItem::handleSurfaceUnmapped);
+        }
+        if (!waitForRelease && eventFilterInstalled && popupShellSurfaces.isEmpty())
+            setFilterEnabled(false);
+    }
+}
+
+void QWaylandQuickWlShellSurfaceItemPrivate::setFilterEnabled(bool enabled)
+{
+    Q_Q(QWaylandQuickWlShellSurfaceItem);
+    static QPointer<QObject> filter;
+
+    if (enabled && filter.isNull()) {
+        qGuiApp->installEventFilter(q);
+        filter = q;
+    } else if (!enabled && !filter.isNull()){
+        qGuiApp->removeEventFilter(filter);
+        filter = nullptr;
+    }
+    eventFilterInstalled = enabled;
+}
+
 QT_END_NAMESPACE
diff --git a/src/compositor/extensions/qwaylandquickwlshellsurfaceitem.h b/src/compositor/extensions/qwaylandquickwlshellsurfaceitem.h
index 7f32c9f3..0b24e43a 100644
--- a/src/compositor/extensions/qwaylandquickwlshellsurfaceitem.h
+++ b/src/compositor/extensions/qwaylandquickwlshellsurfaceitem.h
@@ -69,7 +69,11 @@ Q_SIGNALS:
 private Q_SLOTS:
     void handleStartMove(QWaylandInputDevice *inputDevice);
     void handleStartResize(QWaylandInputDevice *inputDevice, QWaylandWlShellSurface::ResizeEdge edges);
+    void handleSetPopup(QWaylandInputDevice *inputDevice, QWaylandSurface *parent, const QPoint &relativeToParent);
+    void handleShellSurfaceDestroyed();
     void adjustOffsetForNextFrame(const QPointF &offset);
+
+    void handleSurfaceUnmapped();
 protected:
     QWaylandQuickWlShellSurfaceItem(QWaylandQuickWlShellSurfaceItemPrivate &dd, QQuickItem *parent);
 
@@ -77,6 +81,8 @@ protected:
     void mouseReleaseEvent(QMouseEvent *event) Q_DECL_OVERRIDE;
 
     void surfaceChangedEvent(QWaylandSurface *newSurface, QWaylandSurface *oldSurface) Q_DECL_OVERRIDE;
+
+    bool eventFilter(QObject *, QEvent *) Q_DECL_OVERRIDE;
 };
 
 QT_END_NAMESPACE
diff --git a/src/compositor/extensions/qwaylandquickwlshellsurfaceitem_p.h b/src/compositor/extensions/qwaylandquickwlshellsurfaceitem_p.h
index 3e683477..c4adb28d 100644
--- a/src/compositor/extensions/qwaylandquickwlshellsurfaceitem_p.h
+++ b/src/compositor/extensions/qwaylandquickwlshellsurfaceitem_p.h
@@ -52,8 +52,11 @@ QT_BEGIN_NAMESPACE
 // We mean it.
 //
 
+class QWaylandQuickWlShellSurfaceItem;
+
 class Q_WAYLAND_COMPOSITOR_EXPORT QWaylandQuickWlShellSurfaceItemPrivate : public QWaylandQuickItemPrivate
 {
+    Q_DECLARE_PUBLIC(QWaylandQuickWlShellSurfaceItem)
 public:
     enum GrabberState {
         DefaultState,
@@ -66,8 +69,13 @@ public:
         , shellSurface(Q_NULLPTR)
         , moveItem(Q_NULLPTR)
         , grabberState(DefaultState)
+        , isPopup(false)
     {}
 
+    void setIsPopup(bool popup);
+    void setFilterEnabled(bool enabled);
+    static void closePopups();
+
     QWaylandWlShellSurface *shellSurface;
     QQuickItem *moveItem;
 
@@ -85,6 +93,11 @@ public:
         QPointF initialMousePos;
         bool initialized;
     } resizeState;
+
+    static QVector<QWaylandWlShellSurface*> popupShellSurfaces;
+    static bool eventFilterInstalled;
+    static bool waitForRelease;
+    bool isPopup;
 };
 
 QT_END_NAMESPACE
diff --git a/src/imports/compositor/qwaylandmousetracker.cpp b/src/imports/compositor/qwaylandmousetracker.cpp
index e54321f1..a77d6b1a 100644
--- a/src/imports/compositor/qwaylandmousetracker.cpp
+++ b/src/imports/compositor/qwaylandmousetracker.cpp
@@ -87,6 +87,7 @@ QWaylandMouseTracker::QWaylandMouseTracker(QQuickItem *parent)
     Q_D(QWaylandMouseTracker);
     setFiltersChildMouseEvents(true);
     setAcceptHoverEvents(true);
+    setAcceptedMouseButtons(Qt::AllButtons);
     setCursor(QCursor(d->cursorPixmap));
 }