From 05200f9266a4e8e723450abb281c597a48da2e9f Mon Sep 17 00:00:00 2001
From: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>
Date: Sun, 22 Sep 2019 14:33:33 +0200
Subject: Cleanup: unify idiosyncratic singletons

The way we handle singletons in QML, QML insists on allocating the
objects. This leads to a very idiosyncratic way of handling
singletons: The global instance pointer is set in the constructor.

Unify all these by implementing a "SillySingleton" template. All
of the weird singleton-classes can derive from this template and
don't have to bother with reimplementing the instance() function
with all the safety-checks, etc.

This serves firstly as documentation but also improves debugging
as we will now see wanted and unwanted creation and destruction
of these weird singletons.

Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>
---
 qt-models/divelistmodel.cpp | 8 --------
 qt-models/divelistmodel.h   | 6 ++----
 qt-models/gpslistmodel.cpp  | 9 ---------
 qt-models/gpslistmodel.h    | 6 ++----
 4 files changed, 4 insertions(+), 25 deletions(-)

(limited to 'qt-models')

diff --git a/qt-models/divelistmodel.cpp b/qt-models/divelistmodel.cpp
index 779e695ab..e2fddbf83 100644
--- a/qt-models/divelistmodel.cpp
+++ b/qt-models/divelistmodel.cpp
@@ -134,11 +134,8 @@ QString DiveListSortModel::tripShortDate(const QString &section)
 	return QStringLiteral("%1\n'%2").arg(firstMonth,firstTime.toString("yy"));
 }
 
-DiveListModel *DiveListModel::m_instance = NULL;
-
 DiveListModel::DiveListModel(QObject *parent) : QAbstractListModel(parent)
 {
-	m_instance = this;
 }
 
 void DiveListModel::insertDive(int i)
@@ -274,11 +271,6 @@ QString DiveListModel::startAddDive()
 	return QString::number(d->id);
 }
 
-DiveListModel *DiveListModel::instance()
-{
-	return m_instance;
-}
-
 struct dive *DiveListModel::getDive(int i)
 {
 	if (i < 0 || i >= dive_table.nr) {
diff --git a/qt-models/divelistmodel.h b/qt-models/divelistmodel.h
index d6eb07463..cccece51d 100644
--- a/qt-models/divelistmodel.h
+++ b/qt-models/divelistmodel.h
@@ -6,6 +6,7 @@
 #include <QSortFilterProxyModel>
 
 #include "core/subsurface-qt/DiveObjectHelper.h"
+#include "core/singleton.h"
 
 class DiveListSortModel : public QSortFilterProxyModel
 {
@@ -28,7 +29,7 @@ private:
 	void updateFilterState();
 };
 
-class DiveListModel : public QAbstractListModel
+class DiveListModel : public QAbstractListModel, public SillySingleton<DiveListModel>
 {
 	Q_OBJECT
 public:
@@ -45,7 +46,6 @@ public:
 		DepthDurationRole,
 	};
 
-	static DiveListModel *instance();
 	DiveListModel(QObject *parent = 0);
 	void addDive(const QList<dive *> &listOfDives);
 	void addAllDives();
@@ -63,8 +63,6 @@ public:
 	QString startAddDive();
 	void resetInternalData();
 	Q_INVOKABLE DiveObjectHelper at(int i);
-private:
-	static DiveListModel *m_instance;
 };
 
 #endif // DIVELISTMODEL_H
diff --git a/qt-models/gpslistmodel.cpp b/qt-models/gpslistmodel.cpp
index 8d874d67b..8a623bf00 100644
--- a/qt-models/gpslistmodel.cpp
+++ b/qt-models/gpslistmodel.cpp
@@ -3,11 +3,8 @@
 #include "core/qthelper.h"
 #include <QVector>
 
-GpsListModel *GpsListModel::m_instance = NULL;
-
 GpsListModel::GpsListModel(QObject *parent) : QAbstractListModel(parent)
 {
-	m_instance = this;
 }
 
 void GpsListModel::update()
@@ -62,9 +59,3 @@ QHash<int, QByteArray> GpsListModel::roleNames() const
 	roles[GpsLongitudeRole] = "longitude";
 	return roles;
 }
-
-GpsListModel *GpsListModel::instance()
-{
-	return m_instance;
-}
-
diff --git a/qt-models/gpslistmodel.h b/qt-models/gpslistmodel.h
index a1c82e5d6..14145d065 100644
--- a/qt-models/gpslistmodel.h
+++ b/qt-models/gpslistmodel.h
@@ -3,10 +3,10 @@
 #define GPSLISTMODEL_H
 
 #include "core/gpslocation.h"
-#include <QObject>
+#include "core/singleton.h"
 #include <QAbstractListModel>
 
-class GpsListModel : public QAbstractListModel
+class GpsListModel : public QAbstractListModel, public SillySingleton<GpsListModel>
 {
 	Q_OBJECT
 public:
@@ -19,7 +19,6 @@ public:
 		GpsWhenRole
 	};
 
-	static GpsListModel *instance();
 	GpsListModel(QObject *parent = 0);
 	void clear();
 	int rowCount(const QModelIndex &parent = QModelIndex()) const;
@@ -28,7 +27,6 @@ public:
 	void update();
 private:
 	QVector<gpsTracker> m_gpsFixes;
-	static GpsListModel *m_instance;
 };
 
 #endif // GPSLISTMODEL_H
-- 
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