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>

1 files changed, 2 insertions, 3 deletions

diff --git a/core/btdiscovery.h b/core/btdiscovery.h
index d6c25d8b0..a7d68decd 100644
--- a/core/btdiscovery.h
+++ b/core/btdiscovery.h
@@ -10,6 +10,7 @@
 #include <QBluetoothDeviceDiscoveryAgent>
 #include <QBluetoothUuid>
 #include "core/libdivecomputer.h"
+#include "core/singleton.h"
 
 #if defined(Q_OS_ANDROID)
 #include <QAndroidJniObject>
@@ -23,13 +24,12 @@ QString extractBluetoothAddress(const QString &address);
 QString extractBluetoothNameAddress(const QString &address, QString &name);
 QBluetoothDeviceInfo getBtDeviceInfo(const QString &devaddr);
 
-class BTDiscovery : public QObject {
+class BTDiscovery : public QObject, public SillySingleton<BTDiscovery> {
 	Q_OBJECT
 
 public:
 	BTDiscovery(QObject *parent = NULL);
 	~BTDiscovery();
-	static BTDiscovery *instance();
 
 	struct btPairedDevice {
 		QString address;
@@ -57,7 +57,6 @@ public:
 	void discoverAddress(QString address);
 
 private:
-	static BTDiscovery *m_instance;
 	bool m_btValid;
 	bool m_showNonDiveComputers;