Cleanup: make DiveTripModel a global object

DiveTripModel (the model describing the dive-list) was destroyed
and recreated on every reset of the list. This seems excessive.
Instead - in analogy to most other models - make it a single
global object.

Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>

7 files changed, 31 insertions, 28 deletions

diff --git a/desktop-widgets/divelistview.cpp b/desktop-widgets/divelistview.cpp
index eb225e593..57bc0d9e1 100644
--- a/desktop-widgets/divelistview.cpp
+++ b/desktop-widgets/divelistview.cpp
@@ -36,8 +36,7 @@ DiveListView::DiveListView(QWidget *parent) : QTreeView(parent), mouseClickSelec
 	model->setSortRole(DiveTripModel::SORT_ROLE);
 	model->setFilterKeyColumn(-1); // filter all columns
 	model->setFilterCaseSensitivity(Qt::CaseInsensitive);
-	DiveTripModel *tripModel = new DiveTripModel(this);
-	model->setSourceModel(tripModel);
+	model->setSourceModel(DiveTripModel::instance());
 	setModel(model);
 
 	setSortingEnabled(false);
@@ -50,7 +49,7 @@ DiveListView::DiveListView(QWidget *parent) : QTreeView(parent), mouseClickSelec
 	installEventFilter(this);
 
 	for (int i = DiveTripModel::NR; i < DiveTripModel::COLUMNS; i++)
-		calculateInitialColumnWidth(tripModel, i);
+		calculateInitialColumnWidth(i);
 	setColumnWidths();
 }
 
@@ -72,13 +71,13 @@ DiveListView::~DiveListView()
 	settings.endGroup();
 }
 
-void DiveListView::calculateInitialColumnWidth(const DiveTripModel &tripModel, int col)
+void DiveListView::calculateInitialColumnWidth(int col)
 {
 	const QFontMetrics metrics(defaultModelFont());
 	int em = metrics.width('m');
 	int zw = metrics.width('0');
 
-	QString header_txt = tripModel.headerData(col, Qt::Horizontal, Qt::DisplayRole).toString();
+	QString header_txt = DiveTripModel::instance()->headerData(col, Qt::Horizontal, Qt::DisplayRole).toString();
 	int width = metrics.width(header_txt);
 	int sw = 0;
 	switch (col) {
@@ -422,18 +421,13 @@ void DiveListView::reload(DiveTripModel::Layout layout, bool forceSort)
 	header()->setSectionsClickable(true);
 	connect(header(), SIGNAL(sectionPressed(int)), this, SLOT(headerClicked(int)), Qt::UniqueConnection);
 
-	QSortFilterProxyModel *m = qobject_cast<QSortFilterProxyModel *>(model());
-	QAbstractItemModel *oldModel = m->sourceModel();
-	DiveTripModel *tripModel = new DiveTripModel(this);
-	tripModel->setLayout(layout);
-
-	m->setSourceModel(tripModel);
-	if (oldModel)
-		delete oldModel;
+	DiveTripModel *tripModel = DiveTripModel::instance();
+	tripModel->setLayout(layout);	// Note: setLayout() resets the whole model
 
 	if (!forceSort)
 		return;
 
+	QSortFilterProxyModel *m = qobject_cast<QSortFilterProxyModel *>(model());
 	sortByColumn(sortColumn, currentOrder);
 	if (amount_selected && current_dive != NULL) {
 		selectDive(selected_dive, true);
diff --git a/desktop-widgets/divelistview.h b/desktop-widgets/divelistview.h
index 396bef8ce..7e2b6425d 100644
--- a/desktop-widgets/divelistview.h
+++ b/desktop-widgets/divelistview.h
@@ -78,7 +78,7 @@ private:
 	QMultiHash<dive_trip_t *, int> selectedDives;
 	void merge_trip(const QModelIndex &a, const int offset);
 	void setColumnWidths();
-	void calculateInitialColumnWidth(const DiveTripModel &tripModel, int col);
+	void calculateInitialColumnWidth(int col);
 	void backupExpandedRows();
 	void restoreExpandedRows();
 	int lastVisibleColumn();
diff --git a/qt-models/divetripmodel.cpp b/qt-models/divetripmodel.cpp
index 384da6b89..b94eaa985 100644
--- a/qt-models/divetripmodel.cpp
+++ b/qt-models/divetripmodel.cpp
@@ -437,6 +437,12 @@ int DiveItem::weight() const
 	return tw.grams;
 }
 
+DiveTripModel *DiveTripModel::instance()
+{
+	static DiveTripModel self;
+	return &self;
+}
+
 DiveTripModel::DiveTripModel(QObject *parent) :
 	TreeModel(parent),
 	currentLayout(TREE)
@@ -586,9 +592,11 @@ void DiveTripModel::setupModelData()
 
 	beginResetModel();
 
+	clear();
 	if (autogroup)
 		autogroup_dives();
 	dive_table.preexisting = dive_table.nr;
+	QMap<dive_trip_t *, TripItem *> trips;
 	while (--i >= 0) {
 		struct dive *dive = get_dive(i);
 		update_cylinder_related_info(dive);
@@ -598,7 +606,7 @@ void DiveTripModel::setupModelData()
 		diveItem->diveId = dive->id;
 
 		if (!trip || currentLayout == LIST) {
-			diveItem->parent = rootItem;
+			diveItem->parent = rootItem.get();
 			rootItem->children.push_back(diveItem);
 			continue;
 		}
@@ -608,7 +616,7 @@ void DiveTripModel::setupModelData()
 		if (!trips.keys().contains(trip)) {
 			TripItem *tripItem = new TripItem();
 			tripItem->trip = trip;
-			tripItem->parent = rootItem;
+			tripItem->parent = rootItem.get();
 			tripItem->children.push_back(diveItem);
 			trips[trip] = tripItem;
 			rootItem->children.push_back(tripItem);
diff --git a/qt-models/divetripmodel.h b/qt-models/divetripmodel.h
index fc17aff92..32a656bfe 100644
--- a/qt-models/divetripmodel.h
+++ b/qt-models/divetripmodel.h
@@ -93,6 +93,7 @@ public:
 		CURRENT
 	};
 
+	static DiveTripModel *instance();
 	Qt::ItemFlags flags(const QModelIndex &index) const;
 	QVariant headerData(int section, Qt::Orientation orientation, int role = Qt::DisplayRole) const;
 	bool setData(const QModelIndex &index, const QVariant &value, int role = Qt::EditRole);
@@ -102,7 +103,6 @@ public:
 
 private:
 	void setupModelData();
-	QMap<dive_trip_t *, TripItem *> trips;
 	Layout currentLayout;
 };
 
diff --git a/qt-models/treemodel.cpp b/qt-models/treemodel.cpp
index 5ddd2d3a2..3c76cc939 100644
--- a/qt-models/treemodel.cpp
+++ b/qt-models/treemodel.cpp
@@ -32,12 +32,12 @@ QVariant TreeItem::data(int, int) const
 TreeModel::TreeModel(QObject *parent) : QAbstractItemModel(parent)
 {
 	columns = 0; // I'm not sure about this one - I can't see where it gets initialized
-	rootItem = new TreeItem();
+	rootItem.reset(new TreeItem);
 }
 
-TreeModel::~TreeModel()
+void TreeModel::clear()
 {
-	delete rootItem;
+	rootItem.reset(new TreeItem);
 }
 
 QVariant TreeModel::data(const QModelIndex &index, int role) const
@@ -64,7 +64,7 @@ QModelIndex TreeModel::index(int row, int column, const QModelIndex &parent) con
 	if (!hasIndex(row, column, parent))
 		return QModelIndex();
 
-	TreeItem *parentItem = (!parent.isValid()) ? rootItem : static_cast<TreeItem *>(parent.internalPointer());
+	TreeItem *parentItem = (!parent.isValid()) ? rootItem.get() : static_cast<TreeItem *>(parent.internalPointer());
 
 	TreeItem *childItem = parentItem->children[row];
 
@@ -79,7 +79,7 @@ QModelIndex TreeModel::parent(const QModelIndex &index) const
 	TreeItem *childItem = static_cast<TreeItem *>(index.internalPointer());
 	TreeItem *parentItem = childItem->parent;
 
-	if (parentItem == rootItem || !parentItem)
+	if (parentItem == rootItem.get() || !parentItem)
 		return QModelIndex();
 
 	return createIndex(parentItem->row(), 0, parentItem);
@@ -90,7 +90,7 @@ int TreeModel::rowCount(const QModelIndex &parent) const
 	TreeItem *parentItem;
 
 	if (!parent.isValid())
-		parentItem = rootItem;
+		parentItem = rootItem.get();
 	else
 		parentItem = static_cast<TreeItem *>(parent.internalPointer());
 
diff --git a/qt-models/treemodel.h b/qt-models/treemodel.h
index e68ae1c32..3b2b407e0 100644
--- a/qt-models/treemodel.h
+++ b/qt-models/treemodel.h
@@ -4,6 +4,7 @@
 
 #include <QAbstractItemModel>
 #include <QCoreApplication>
+#include <memory>
 
 struct TreeItem {
 	Q_DECLARE_TR_FUNCTIONS(TreeItemDT)
@@ -25,16 +26,16 @@ class TreeModel : public QAbstractItemModel {
 	Q_OBJECT
 public:
 	TreeModel(QObject *parent = 0);
-	~TreeModel();
 	QVariant data(const QModelIndex &index, int role) const;
 	int rowCount(const QModelIndex &parent = QModelIndex()) const;
 	int columnCount(const QModelIndex &parent = QModelIndex()) const;
 	QModelIndex index(int row, int column, const QModelIndex &parent = QModelIndex()) const;
 	QModelIndex parent(const QModelIndex &child) const;
+	void clear();
 
 protected:
 	int columns;
-	TreeItem *rootItem;
+	std::unique_ptr<TreeItem> rootItem;
 };
 
 #endif
diff --git a/qt-models/yearlystatisticsmodel.cpp b/qt-models/yearlystatisticsmodel.cpp
index 9cbb19a1d..c83a803c2 100644
--- a/qt-models/yearlystatisticsmodel.cpp
+++ b/qt-models/yearlystatisticsmodel.cpp
@@ -187,7 +187,7 @@ void YearlyStatisticsModel::update_yearly_stats()
 			month++;
 		}
 		rootItem->children.append(item);
-		item->parent = rootItem;
+		item->parent = rootItem.get();
 	}
 
 
@@ -199,7 +199,7 @@ void YearlyStatisticsModel::update_yearly_stats()
 			iChild->parent = item;
 		}
 		rootItem->children.append(item);
-		item->parent = rootItem;
+		item->parent = rootItem.get();
 	}
 
 	/* Show the statistic sorted by dive type */
@@ -213,6 +213,6 @@ void YearlyStatisticsModel::update_yearly_stats()
 			iChild->parent = item;
 		}
 		rootItem->children.append(item);
-		item->parent = rootItem;
+		item->parent = rootItem.get();
 	}
 }