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, 0 insertions, 14 deletions

diff --git a/core/btdiscovery.cpp b/core/btdiscovery.cpp
index 8db1e02cc..1387be400 100644
--- a/core/btdiscovery.cpp
+++ b/core/btdiscovery.cpp
@@ -15,7 +15,6 @@ extern QMap<QString, dc_descriptor_t *> descriptorLookup;
 namespace {
 	QHash<QString, QBluetoothDeviceInfo> btDeviceInfo;
 }
-BTDiscovery *BTDiscovery::m_instance = NULL;
 
 static dc_descriptor_t *getDeviceType(QString btName)
 // central function to convert a BT name to a Subsurface known vendor/model pair
@@ -139,11 +138,6 @@ BTDiscovery::BTDiscovery(QObject*) : m_btValid(false),
 	m_showNonDiveComputers(false),
 	discoveryAgent(nullptr)
 {
-	if (m_instance) {
-		qDebug() << "trying to create an additional BTDiscovery object";
-		return;
-	}
-	m_instance = this;
 #if defined(BT_SUPPORT)
 	QLoggingCategory::setFilterRules(QStringLiteral("qt.bluetooth* = true"));
 	BTDiscoveryReDiscover();
@@ -202,19 +196,11 @@ void BTDiscovery::BTDiscoveryReDiscover()
 
 BTDiscovery::~BTDiscovery()
 {
-	m_instance = NULL;
 #if defined(BT_SUPPORT)
 	delete discoveryAgent;
 #endif
 }
 
-BTDiscovery *BTDiscovery::instance()
-{
-	if (!m_instance)
-		m_instance = new BTDiscovery();
-	return m_instance;
-}
-
 #if defined(BT_SUPPORT)
 extern void addBtUuid(QBluetoothUuid uuid);
 extern QHash<QString, QStringList> productList;