Rename QML singleton to Bobink and simplify singleton lifecycle

Replace QML_ELEMENT with QML_NAMED_ELEMENT(Bobink) so QML references
use `Bobink` instead of `BobinkClient`. Remove instance()/create()
factory in favor of inline s_instance set in the constructor. Import
BobinkPlugin statically in demo, link demo to BobinkQtOpcUaplugin,
and make library link dependencies PUBLIC. Add .qtcreator to gitignore.

4 files changed, 25 insertions, 49 deletions

diff --git a/src/BobinkClient.cpp b/src/BobinkClient.cpp
index f8303a3..01f9912 100644
--- a/src/BobinkClient.cpp
+++ b/src/BobinkClient.cpp
@@ -11,8 +11,6 @@
 
 using namespace Qt::Literals::StringLiterals;
 
-BobinkClient *BobinkClient::s_instance = nullptr;
-
 static QString
 defaultPkiDir ()
 {
@@ -36,35 +34,15 @@ BobinkClient::BobinkClient (QObject *parent)
     : QObject (parent), m_provider (new QOpcUaProvider (this)),
       m_pkiDir (defaultPkiDir ())
 {
+  // Singleton pattern: construct only once
+  Q_ASSERT(!s_instance);
   ensurePkiDirs (m_pkiDir);
   setupClient ();
   autoDetectPki ();
   applyPki ();
   connect (&m_discoveryTimer, &QTimer::timeout, this,
            &BobinkClient::doDiscovery);
-}
-
-BobinkClient::~BobinkClient ()
-{
-  if (s_instance == this)
-    s_instance = nullptr;
-}
-
-BobinkClient *
-BobinkClient::instance ()
-{
-  return s_instance;
-}
-
-BobinkClient *
-BobinkClient::create (QQmlEngine *, QJSEngine *)
-{
-  if (!s_instance)
-    {
-      s_instance = new BobinkClient;
-      QJSEngine::setObjectOwnership (s_instance, QJSEngine::CppOwnership);
-    }
-  return s_instance;
+  s_instance = this;
 }
 
 void
diff --git a/src/BobinkClient.h b/src/BobinkClient.h
index 5b7b284..3f36e75 100644
--- a/src/BobinkClient.h
+++ b/src/BobinkClient.h
@@ -25,8 +25,8 @@ class BobinkAuth;
 class BobinkClient : public QObject
 {
   Q_OBJECT
-  QML_ELEMENT
   QML_SINGLETON
+  QML_NAMED_ELEMENT (Bobink)
 
   Q_PROPERTY (bool connected READ connected NOTIFY connectedChanged)
   Q_PROPERTY (QString serverUrl READ serverUrl WRITE setServerUrl NOTIFY
@@ -45,16 +45,18 @@ class BobinkClient : public QObject
       QString keyFile READ keyFile WRITE setKeyFile NOTIFY keyFileChanged)
 
 public:
-  explicit BobinkClient (QObject *parent = nullptr);
-  ~BobinkClient () override;
+  BobinkClient (QObject *parent = nullptr);
+  // ~BobinkClient () override;
 
-  static BobinkClient *instance ();
+  static inline BobinkClient *s_instance = nullptr;
+
+  // static BobinkClient *instance ();
 
   /**
    * @brief  QML singleton factory.
    * @note   CppOwnership — lives for the process lifetime.
    */
-  static BobinkClient *create (QQmlEngine *qmlEngine, QJSEngine *jsEngine);
+  // static BobinkClient *create (QQmlEngine *qmlEngine, QJSEngine *jsEngine);
 
   bool connected () const;
 
@@ -155,7 +157,6 @@ private slots:
 private:
   void setupClient ();
 
-  static BobinkClient *s_instance;
   QOpcUaProvider *m_provider = nullptr;
   QOpcUaClient *m_client = nullptr;
   BobinkAuth *m_auth = nullptr;
diff --git a/src/BobinkNode.cpp b/src/BobinkNode.cpp
index a39c195..fed87bc 100644
--- a/src/BobinkNode.cpp
+++ b/src/BobinkNode.cpp
@@ -104,7 +104,7 @@ BobinkNode::componentComplete ()
   QQuickItem::componentComplete ();
   m_componentComplete = true;
 
-  auto *client = BobinkClient::instance ();
+  auto *client = BobinkClient::s_instance;
   if (client)
     connect (client, &BobinkClient::connectedChanged, this,
              &BobinkNode::handleClientConnectedChanged);
@@ -137,7 +137,7 @@ BobinkNode::startMonitoring ()
   if (m_opcuaNode || m_nodeId.isEmpty ())
     return;
 
-  auto *client = BobinkClient::instance ();
+  auto *client = BobinkClient::s_instance;
   if (!client || !client->connected ())
     return;
 
@@ -245,11 +245,10 @@ BobinkNode::handleAttributeWritten (QOpcUa::NodeAttribute attr,
 void
 BobinkNode::handleClientConnectedChanged ()
 {
-  auto *client = BobinkClient::instance ();
-  if (!client)
+  if (!BobinkClient::s_instance)
     return;
 
-  if (client->connected ())
+  if (BobinkClient::s_instance->connected ())
     {
       if (m_componentComplete && isVisible ())
         startMonitoring ();
@@ -263,8 +262,7 @@ BobinkNode::handleClientConnectedChanged ()
 void
 BobinkNode::handleAttributeReadFinished (QOpcUa::NodeAttributes attrs)
 {
-  auto *client = BobinkClient::instance ();
-  if (!client || !m_opcuaNode)
+  if (!BobinkClient::s_instance || !m_opcuaNode)
     return;
 
   for (int bit = 0; bit < 27; ++bit)
@@ -276,12 +274,12 @@ BobinkNode::handleAttributeReadFinished (QOpcUa::NodeAttributes attrs)
       auto sc = m_opcuaNode->attributeError (attr);
       QLatin1StringView name = nameFromAttribute (attr);
       if (sc == QOpcUa::UaStatusCode::Good)
-        emit client->statusMessage (
+        emit BobinkClient::s_instance->statusMessage (
             QStringLiteral ("Read %1.%2 = %3")
                 .arg (m_nodeId, name,
                       m_opcuaNode->attribute (attr).toString ()));
       else
-        emit client->statusMessage (
+        emit BobinkClient::s_instance->statusMessage (
             QStringLiteral ("Read %1.%2 failed: 0x%3")
                 .arg (m_nodeId, name)
                 .arg (static_cast<quint32> (sc), 8, 16, QLatin1Char ('0')));
@@ -292,15 +290,14 @@ void
 BobinkNode::handleEnableMonitoringFinished (QOpcUa::NodeAttribute,
                                             QOpcUa::UaStatusCode statusCode)
 {
-  auto *client = BobinkClient::instance ();
-  if (!client)
+  if (!BobinkClient::s_instance)
     return;
 
   if (statusCode == QOpcUa::Good)
-    emit client->statusMessage (
+    emit BobinkClient::s_instance->statusMessage (
         QStringLiteral ("Monitoring started: %1").arg (m_nodeId));
   else
-    emit client->statusMessage (
+    emit BobinkClient::s_instance->statusMessage (
         QStringLiteral ("Monitoring failed for %1: 0x%2")
             .arg (m_nodeId)
             .arg (static_cast<quint32> (statusCode), 8, 16,
@@ -311,15 +308,14 @@ void
 BobinkNode::handleDisableMonitoringFinished (QOpcUa::NodeAttribute,
                                              QOpcUa::UaStatusCode statusCode)
 {
-  auto *client = BobinkClient::instance ();
-  if (!client)
+  if (!BobinkClient::s_instance)
     return;
 
   if (statusCode == QOpcUa::Good)
-    emit client->statusMessage (
+    emit BobinkClient::s_instance->statusMessage (
         QStringLiteral ("Monitoring stopped: %1").arg (m_nodeId));
   else
-    emit client->statusMessage (
+    emit BobinkClient::s_instance->statusMessage (
         QStringLiteral ("Stop monitoring failed for %1: 0x%2")
             .arg (m_nodeId)
             .arg (static_cast<quint32> (statusCode), 8, 16,
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 5898132..1292194 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -1,3 +1,4 @@
+qt_add_library(BobinkQtOpcUa STATIC)
 # BobinkQtOpcUa — QML module wrapping QtOpcUa for declarative use.
 qt_add_qml_module(
   BobinkQtOpcUa
@@ -15,4 +16,4 @@ qt_add_qml_module(
   OUTPUT_DIRECTORY
   "${CMAKE_BINARY_DIR}/qml/Bobink")
 
-target_link_libraries(BobinkQtOpcUa PRIVATE Qt6::Core Qt6::Quick Qt6::OpcUa)
+target_link_libraries(BobinkQtOpcUa PUBLIC Qt6::Core Qt6::Quick Qt6::OpcUa)