Fix for popups

Introduce a singleton event filter that keeps working if
the popup is deleted. Move the event filter class to
qwaylandquickshellsurfaceitem, so it can be used by the
XDG shell.

Change-Id: I58998a7e62697bf6f54536d2c2e2732ceb4d970e
Reviewed-by: Johan Helsing <johan.helsing@qt.io>
Reviewed-by: Pier Luigi Fiorini <pierluigi.fiorini@gmail.com>

4 files changed, 104 insertions, 66 deletions

diff --git a/src/compositor/extensions/qwaylandquickshellsurfaceitem.cpp b/src/compositor/extensions/qwaylandquickshellsurfaceitem.cpp
index 4b087183f..bfad242cc 100644
--- a/src/compositor/extensions/qwaylandquickshellsurfaceitem.cpp
+++ b/src/compositor/extensions/qwaylandquickshellsurfaceitem.cpp
@@ -38,6 +38,7 @@
 #include "qwaylandquickshellsurfaceitem_p.h"
 
 #include <QtWaylandCompositor/QWaylandShellSurface>
+#include <QGuiApplication>
 
 QT_BEGIN_NAMESPACE
 
@@ -148,4 +149,84 @@ void QWaylandQuickShellSurfaceItem::mouseReleaseEvent(QMouseEvent *event)
         QWaylandQuickItem::mouseReleaseEvent(event);
 }
 
+/*!
+\class QWaylandQuickShellEventFilter
+\brief QWaylandQuickShellEventFilter implements a Wayland popup grab
+\internal
+*/
+
+void QWaylandQuickShellEventFilter::startFilter(QWaylandClient *client, CallbackFunction closePopups)
+{
+    if (!self)
+        self = new QWaylandQuickShellEventFilter(qGuiApp);
+    if (!self->eventFilterInstalled) {
+        qGuiApp->installEventFilter(self);
+        self->eventFilterInstalled = true;
+        self->client = client;
+        self->closePopups = closePopups;
+    }
+}
+
+void QWaylandQuickShellEventFilter::cancelFilter()
+{
+    if (!self)
+        return;
+    if (self->eventFilterInstalled && !self->waitForRelease)
+        self->stopFilter();
+}
+
+void QWaylandQuickShellEventFilter::stopFilter()
+{
+    if (eventFilterInstalled) {
+        qGuiApp->removeEventFilter(this);
+        eventFilterInstalled = false;
+    }
+}
+QWaylandQuickShellEventFilter *QWaylandQuickShellEventFilter::self = nullptr;
+
+QWaylandQuickShellEventFilter::QWaylandQuickShellEventFilter(QObject *parent)
+    : QObject(parent), eventFilterInstalled(false), waitForRelease(false), closePopups(nullptr)
+{
+}
+
+bool QWaylandQuickShellEventFilter::eventFilter(QObject *receiver, QEvent *e)
+{
+    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);
+        QWaylandQuickShellSurfaceItem *shellSurfaceItem = qobject_cast<QWaylandQuickShellSurfaceItem*>(item);
+        bool press = event->type() == QEvent::MouseButtonPress;
+        bool finalRelease = (event->type() == QEvent::MouseButtonRelease) && (event->buttons() == Qt::NoButton);
+        bool popupClient = shellSurfaceItem && shellSurfaceItem->surface()->client() == client;
+
+        if (waitForRelease) {
+            // We are eating events until all mouse buttons are released
+            if (finalRelease) {
+                waitForRelease = false;
+                stopFilter();
+            }
+            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.
+            waitForRelease = true;
+            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.
+            stopFilter();
+        }
+    }
+
+    return false;
+}
+
 QT_END_NAMESPACE
diff --git a/src/compositor/extensions/qwaylandquickshellsurfaceitem_p.h b/src/compositor/extensions/qwaylandquickshellsurfaceitem_p.h
index b2d4780ab..c2f46917e 100644
--- a/src/compositor/extensions/qwaylandquickshellsurfaceitem_p.h
+++ b/src/compositor/extensions/qwaylandquickshellsurfaceitem_p.h
@@ -78,6 +78,26 @@ public:
     virtual bool mouseReleaseEvent(QMouseEvent *) { return false; }
 };
 
+class Q_WAYLAND_COMPOSITOR_EXPORT QWaylandQuickShellEventFilter : public QObject
+{
+    Q_OBJECT
+public:
+    typedef void (*CallbackFunction)(void);
+    static void startFilter(QWaylandClient *client, CallbackFunction closePopupCallback);
+    static void cancelFilter();
+
+private:
+    void stopFilter();
+
+    QWaylandQuickShellEventFilter(QObject *parent = nullptr);
+    bool eventFilter(QObject *, QEvent *) Q_DECL_OVERRIDE;
+    bool eventFilterInstalled;
+    bool waitForRelease;
+    QPointer<QWaylandClient> client;
+    CallbackFunction closePopups;
+    static QWaylandQuickShellEventFilter *self;
+};
+
 QT_END_NAMESPACE
 
 #endif // QWAYLANDQUICKSHELLSURFACEITEM_P_H
diff --git a/src/compositor/extensions/qwaylandwlshellintegration.cpp b/src/compositor/extensions/qwaylandwlshellintegration.cpp
index ef4e1efc6..5c0fe7c9d 100644
--- a/src/compositor/extensions/qwaylandwlshellintegration.cpp
+++ b/src/compositor/extensions/qwaylandwlshellintegration.cpp
@@ -40,7 +40,6 @@
 #include <QtWaylandCompositor/QWaylandWlShellSurface>
 #include <QtWaylandCompositor/QWaylandQuickShellSurfaceItem>
 #include <QtWaylandCompositor/QWaylandInputDevice>
-#include <QGuiApplication>
 
 QT_BEGIN_NAMESPACE
 
@@ -158,8 +157,6 @@ bool WlShellIntegration::mouseReleaseEvent(QMouseEvent *event)
 }
 
 QVector<QWaylandWlShellSurface*> WlShellIntegration::popupShellSurfaces;
-bool WlShellIntegration::eventFilterInstalled = false;
-bool WlShellIntegration::waitForRelease = false;
 
 void WlShellIntegration::closePopups()
 {
@@ -171,52 +168,11 @@ void WlShellIntegration::closePopups()
     }
 }
 
-bool WlShellIntegration::eventFilter(QObject *receiver, QEvent *e)
-{
-    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);
-        QWaylandQuickShellSurfaceItem *shellSurfaceItem = qobject_cast<QWaylandQuickShellSurfaceItem*>(item);
-        bool press = event->type() == QEvent::MouseButtonPress;
-        bool finalRelease = (event->type() == QEvent::MouseButtonRelease) && (event->buttons() == Qt::NoButton);
-        bool popupClient = shellSurfaceItem && shellSurfaceItem->surface()->client() == m_shellSurface->surface()->client();
-
-        if (waitForRelease) {
-            // We are eating events until all mouse buttons are released
-            if (finalRelease) {
-                waitForRelease = false;
-                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.
-            waitForRelease = true;
-            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.
-            setFilterEnabled(false);
-        }
-    }
-
-    return false;
-}
-
 void WlShellIntegration::setIsPopup(bool popup)
 {
     isPopup = popup;
     if (popup) {
-        if (!eventFilterInstalled)
-           setFilterEnabled(true);
+           QWaylandQuickShellEventFilter::startFilter(m_shellSurface->surface()->client(), &closePopups);
 
         if (!popupShellSurfaces.contains(m_shellSurface)) {
             popupShellSurfaces.append(m_shellSurface);
@@ -229,23 +185,9 @@ void WlShellIntegration::setIsPopup(bool popup)
             QObject::disconnect(m_shellSurface->surface(), &QWaylandSurface::mappedChanged,
                                 this, &WlShellIntegration::handleSurfaceUnmapped);
         }
-        if (!waitForRelease && eventFilterInstalled && popupShellSurfaces.isEmpty())
-            setFilterEnabled(false);
-    }
-}
-
-void WlShellIntegration::setFilterEnabled(bool enabled)
-{
-    static QPointer<QObject> filter;
-
-    if (enabled && filter.isNull()) {
-        qGuiApp->installEventFilter(this);
-        filter = this;
-    } else if (!enabled && !filter.isNull()){
-        qGuiApp->removeEventFilter(filter);
-        filter = nullptr;
+        if (popupShellSurfaces.isEmpty())
+            QWaylandQuickShellEventFilter::cancelFilter();
     }
-    eventFilterInstalled = enabled;
 }
 
 }
diff --git a/src/compositor/extensions/qwaylandwlshellintegration_p.h b/src/compositor/extensions/qwaylandwlshellintegration_p.h
index 486077200..07bbc63cb 100644
--- a/src/compositor/extensions/qwaylandwlshellintegration_p.h
+++ b/src/compositor/extensions/qwaylandwlshellintegration_p.h
@@ -79,10 +79,7 @@ private:
         Move
     };
 
-    bool eventFilter(QObject *, QEvent *) Q_DECL_OVERRIDE;
-
     void setIsPopup(bool popup);
-    void setFilterEnabled(bool enabled);
     static void closePopups();
 
     QWaylandQuickShellSurfaceItem *m_item;
@@ -102,8 +99,6 @@ private:
     } resizeState;
 
     static QVector<QWaylandWlShellSurface*> popupShellSurfaces;
-    static bool eventFilterInstalled;
-    static bool waitForRelease;
     bool isPopup;
 };