Refresh the ScreenGeometry data role whenever a screen is added or changes its geometry.

Summary:
As this happens the screen filtering higher up in the proxy chain
culimating in TasksModel needs to be re-executed, as it compares
ScreenGeometry against a property value set on the model. Without
this update, tasks may disappear from views using TasksModel.

Mapping the trigger conditions to affected rows is deliberately
maximally coarse; see implementation comment in code.

BUG:373075

Reviewers: #plasma, davidedmundson

Subscribers: plasma-devel

Tags: #plasma

Differential Revision: https://phabricator.kde.org/D3628

libtaskmanager/CMakeLists.txt

@@ -4,6 +4,7 @@ add_subdirectory(autotests)
 set(taskmanager_LIB_SRCS
     abstracttasksmodel.cpp
     abstracttasksproxymodeliface.cpp
+    abstractwindowtasksmodel.cpp
     activityinfo.cpp
     concatenatetasksproxymodel.cpp
     flattentaskgroupsproxymodel.cpp
@@ -67,6 +68,7 @@ install(FILES
     abstracttasksmodel.h
     abstracttasksmodeliface.h
     abstracttasksproxymodeliface.h
+    abstractwindowtasksmodel.h
     activityinfo.h
     concatenatetasksproxymodel.h
     flattentaskgroupsproxymodel.h

libtaskmanager/abstractwindowtasksmodel.cpp

@@ -0,0 +1,60 @@
+/********************************************************************
+Copyright 2016  Eike Hein <hein@kde.org>
+
+This library is free software; you can redistribute it and/or
+modify it under the terms of the GNU Lesser General Public
+License as published by the Free Software Foundation; either
+version 2.1 of the License, or (at your option) version 3, or any
+later version accepted by the membership of KDE e.V. (or its
+successor approved by the membership of KDE e.V.), which shall
+act as a proxy defined in Section 6 of version 3 of the license.
+
+This library is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public
+License along with this library.  If not, see <http://www.gnu.org/licenses/>.
+*********************************************************************/
+
+#include "abstractwindowtasksmodel.h"
+
+#include <QGuiApplication>
+#include <QScreen>
+
+namespace TaskManager
+{
+
+AbstractWindowTasksModel::AbstractWindowTasksModel(QObject *parent)
+    : AbstractTasksModel(parent)
+{
+    // TODO: The following will refresh the ScreenGeometry data role for
+    // all rows whenever any screen is added or changes its geometry. No
+    // attempt is made to be intelligent and exempt rows that are tech-
+    // nically unaffected by the change. Doing so would require tracking
+    // far more state (i.e. what screen a window is on) and be so
+    // complicated as to invite bugs. As the trigger conditions are
+    // expected to be rare, this would be premature optimization at this
+    // time. That assessment may change in the future.
+
+    auto screenAdded = [this](const QScreen *screen) {
+        connect(screen, &QScreen::geometryChanged, this,
+            [this]() {
+                dataChanged(index(0, 0), index(rowCount(), 0), QVector<int>{ScreenGeometry});
+            }
+        );
+    };
+
+    connect(qGuiApp, &QGuiApplication::screenAdded, this, screenAdded);
+
+    foreach(const QScreen *screen, QGuiApplication::screens()) {
+        screenAdded(screen);
+    }
+}
+
+AbstractWindowTasksModel::~AbstractWindowTasksModel()
+{
+}
+
+}

libtaskmanager/abstractwindowtasksmodel.h

@@ -0,0 +1,53 @@
+/********************************************************************
+Copyright 2016  Eike Hein <hein.org>
+
+This library is free software; you can redistribute it and/or
+modify it under the terms of the GNU Lesser General Public
+License as published by the Free Software Foundation; either
+version 2.1 of the License, or (at your option) version 3, or any
+later version accepted by the membership of KDE e.V. (or its
+successor approved by the membership of KDE e.V.), which shall
+act as a proxy defined in Section 6 of version 3 of the license.
+
+This library is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public
+License along with this library.  If not, see <http://www.gnu.org/licenses/>.
+*********************************************************************/
+
+#ifndef ABSTRACTWINDOWTASKSMODEL_H
+#define ABSTRACTWINDOWTASKSMODEL_H
+
+#include "abstracttasksmodel.h"
+
+#include "taskmanager_export.h"
+
+namespace TaskManager
+{
+
+/**
+ * @short An abstract base class for window tasks models.
+ *
+ * This class serves as abstract base class for window tasks model implementations.
+ *
+ * It takes care of refreshing the ScreenGeometry data role when screens are added
+ * or a screen changes its geometry.
+ *
+ * @author Eike Hein <hein@kde.org>
+ **/
+
+class TASKMANAGER_EXPORT AbstractWindowTasksModel : public AbstractTasksModel
+{
+    Q_OBJECT
+
+public:
+    explicit AbstractWindowTasksModel(QObject *parent = nullptr);
+    virtual ~AbstractWindowTasksModel();
+};
+
+}
+
+#endif

libtaskmanager/waylandtasksmodel.cpp

@@ -250,7 +250,7 @@ void WaylandTasksModel::Private::dataChanged(KWayland::Client::PlasmaWindow *win
 }
 
 WaylandTasksModel::WaylandTasksModel(QObject *parent)
-    : AbstractTasksModel(parent)
+    : AbstractWindowTasksModel(parent)
     , d(new Private(this))
 {
     d->initWayland();

libtaskmanager/waylandtasksmodel.h

@@ -21,7 +21,7 @@ License along with this library.  If not, see <http://www.gnu.org/licenses/>.
 #ifndef WAYLANDTASKSMODEL_H
 #define WAYLANDTASKSMODEL_H
 
-#include "abstracttasksmodel.h"
+#include "abstractwindowtasksmodel.h"
 
 #include "taskmanager_export.h"
 
@@ -49,7 +49,7 @@ namespace TaskManager
  * @author Eike Hein <hein@kde.org>
  */
 
-class TASKMANAGER_EXPORT WaylandTasksModel : public AbstractTasksModel
+class TASKMANAGER_EXPORT WaylandTasksModel : public AbstractWindowTasksModel
 {
     Q_OBJECT
 

libtaskmanager/xwindowtasksmodel.cpp

@@ -825,7 +825,7 @@ bool XWindowTasksModel::Private::demandsAttention(WId window)
 }
 
 XWindowTasksModel::XWindowTasksModel(QObject *parent)
-    : AbstractTasksModel(parent)
+    : AbstractWindowTasksModel(parent)
     , d(new Private(this))
 {
     d->init();

libtaskmanager/xwindowtasksmodel.h

@@ -21,7 +21,7 @@ License along with this library.  If not, see <http://www.gnu.org/licenses/>.
 #ifndef XWINDOWTASKSMODEL_H
 #define XWINDOWTASKSMODEL_H
 
-#include "abstracttasksmodel.h"
+#include "abstractwindowtasksmodel.h"
 
 #include "taskmanager_export.h"
 
@@ -46,7 +46,7 @@ namespace TaskManager
  * @author Eike Hein <hein@kde.org>
  */
 
-class TASKMANAGER_EXPORT XWindowTasksModel : public AbstractTasksModel
+class TASKMANAGER_EXPORT XWindowTasksModel : public AbstractWindowTasksModel
 {
     Q_OBJECT