feat: add QSFP to hide empty rows in eventmodel

The favourites and tracepoint patches include some rows in the model
that may be empty. To keep the code simple an readable all rows will be
shown. Then a proxy model is put ontop to remove empty rows.

src/models/CMakeLists.txt

@@ -10,6 +10,7 @@ add_library(
     disassemblymodel.cpp
     disassemblyoutput.cpp
     eventmodel.cpp
+    eventmodelproxy.cpp
     filterandzoomstack.cpp
     formattingutils.cpp
     frequencymodel.cpp

src/models/eventmodelproxy.cpp

@@ -0,0 +1,34 @@
+/*
+    SPDX-FileCopyrightText: Lieven Hey <[email protected]>
+    SPDX-FileCopyrightText: 2023 Klarälvdalens Datakonsult AB, a KDAB Group company, [email protected]
+
+    SPDX-License-Identifier: GPL-2.0-or-later
+*/
+
+#include "eventmodelproxy.h"
+#include "eventmodel.h"
+
+EventModelProxy::EventModelProxy(QObject* parent)
+    : QSortFilterProxyModel(parent)
+{
+    setDynamicSortFilter(true);
+    setRecursiveFilteringEnabled(true);
+    setSortRole(EventModel::SortRole);
+    setFilterKeyColumn(EventModel::ThreadColumn);
+    setFilterRole(Qt::DisplayRole);
+}
+
+EventModelProxy::~EventModelProxy() = default;
+
+bool EventModelProxy::filterAcceptsRow(int source_row, const QModelIndex& source_parent) const
+{
+    // index is invalid -> we are at the root node
+    // hide categories that have no children (e.g. favorites, tracepoints)
+    if (!source_parent.isValid()) {
+        const auto model = sourceModel();
+        if (!model->hasChildren(model->index(source_row, 0)))
+            return false;
+    }
+
+    return QSortFilterProxyModel::filterAcceptsRow(source_row, source_parent);
+}

src/models/eventmodelproxy.h

@@ -0,0 +1,21 @@
+/*
+    SPDX-FileCopyrightText: Lieven Hey <[email protected]>
+    SPDX-FileCopyrightText: 2023 Klarälvdalens Datakonsult AB, a KDAB Group company, [email protected]
+
+    SPDX-License-Identifier: GPL-2.0-or-later
+*/
+
+#pragma once
+
+#include <QSortFilterProxyModel>
+
+class EventModelProxy : public QSortFilterProxyModel
+{
+    Q_OBJECT
+public:
+    explicit EventModelProxy(QObject* parent = nullptr);
+    ~EventModelProxy() override;
+
+protected:
+    bool filterAcceptsRow(int source_row, const QModelIndex& source_parent) const override;
+};

src/timelinewidget.cpp

@@ -9,6 +9,7 @@
 
 #include "filterandzoomstack.h"
 #include "models/eventmodel.h"
+#include "models/eventmodelproxy.h"
 #include "resultsutil.h"
 #include "timelinedelegate.h"
 
@@ -61,12 +62,8 @@ TimeLineWidget::TimeLineWidget(PerfParser* parser, QMenu* filterMenu, FilterAndZ
     ui->setupUi(this);
 
     auto* eventModel = new EventModel(this);
-    auto* timeLineProxy = new QSortFilterProxyModel(this);
-    timeLineProxy->setRecursiveFilteringEnabled(true);
+    auto* timeLineProxy = new EventModelProxy(this);
     timeLineProxy->setSourceModel(eventModel);
-    timeLineProxy->setSortRole(EventModel::SortRole);
-    timeLineProxy->setFilterKeyColumn(EventModel::ThreadColumn);
-    timeLineProxy->setFilterRole(Qt::DisplayRole);
     ResultsUtil::connectFilter(ui->timeLineSearch, timeLineProxy);
     ui->timeLineView->setModel(timeLineProxy);
     ui->timeLineView->setSortingEnabled(true);

tests/modeltests/tst_models.cpp

@@ -21,6 +21,7 @@
 
 #include <models/disassemblymodel.h>
 #include <models/eventmodel.h>
+#include <models/eventmodelproxy.h>
 #include <models/sourcecodemodel.h>
 
 namespace {
@@ -673,6 +674,34 @@ private slots:
         QCOMPARE(model.rowCount(favoritesIndex), 0);
     }
 
+    void testEventModelProxy()
+    {
+        const auto events = createEventModelTestData();
+        EventModel model;
+        QAbstractItemModelTester tester(&model);
+        model.setData(events);
+
+        EventModelProxy proxy;
+        proxy.setSourceModel(&model);
+
+        const auto favoritesIndex = model.index(3, 0);
+        const auto processesIndex = model.index(1, 0);
+
+        QCOMPARE(model.rowCount(), 4);
+        QCOMPARE(proxy.rowCount(), 2);
+
+        proxy.setFilterRegularExpression(QStringLiteral("this does not match"));
+        QCOMPARE(proxy.rowCount(), 0);
+        proxy.setFilterRegularExpression(QString());
+        QCOMPARE(proxy.rowCount(), 2);
+
+        model.addToFavorites(model.index(0, 0, processesIndex));
+        QCOMPARE(proxy.rowCount(), 3);
+
+        model.removeFromFavorites(model.index(0, 0, favoritesIndex));
+        QCOMPARE(proxy.rowCount(), 2);
+    }
+
     void testPrettySymbol_data()
     {
         QTest::addColumn<QString>("prettySymbol");