Fix object de-reference crash on deletion

Fix for Issue #1255

src/ui/QGCWaypointListMulti.cc

@@ -2,73 +2,71 @@
 #include "ui_QGCWaypointListMulti.h"
 #include "UASManager.h"
 
+void* QGCWaypointListMulti::_offlineUAS = NULL;
+
 QGCWaypointListMulti::QGCWaypointListMulti(QWidget *parent) :
     QWidget(parent),
-    offline_uas_id(0),
-    ui(new Ui::QGCWaypointListMulti)
+    _ui(new Ui::QGCWaypointListMulti)
 {
-    ui->setupUi(this);
+    _ui->setupUi(this);
     setMinimumSize(600, 80);
-    connect(UASManager::instance(), &UASManager::UASCreated, this, &QGCWaypointListMulti::systemCreated);
-    connect(UASManager::instance(), &UASManager::activeUASSet, this, &QGCWaypointListMulti::systemSetActive);
     
-    WaypointList* list = new WaypointList(ui->stackedWidget, UASManager::instance()->getActiveUASWaypointManager());
-    lists.insert(offline_uas_id, list);
-    ui->stackedWidget->addWidget(list);
+    connect(UASManager::instance(), &UASManager::UASCreated, this, &QGCWaypointListMulti::_systemCreated);
+    connect(UASManager::instance(), &UASManager::activeUASSet, this, &QGCWaypointListMulti::_systemSetActive);
+
+    WaypointList* list = new WaypointList(_ui->stackedWidget, UASManager::instance()->getActiveUASWaypointManager());
+    _lists.insert(_offlineUAS, list);
+    _ui->stackedWidget->addWidget(list);
 
     if (UASManager::instance()->getActiveUAS()) {
-        systemCreated(UASManager::instance()->getActiveUAS());
-        systemSetActive(UASManager::instance()->getActiveUAS());
+        _systemCreated(UASManager::instance()->getActiveUAS());
+        _systemSetActive(UASManager::instance()->getActiveUAS());
     }
 
 }
 
-void QGCWaypointListMulti::systemDeleted(QObject* uas)
+QGCWaypointListMulti::~QGCWaypointListMulti()
+{
+    delete _ui;
+}
+
+void QGCWaypointListMulti::_systemDeleted(QObject* uas)
 {
     // Do not dynamic cast or de-reference QObject, since object is either in destructor or may have already
     // been destroyed.
 
-    UASInterface* mav = static_cast<UASInterface*>(uas);
-    if (mav)
-    {
-        int id = mav->getUASID();
-        WaypointList* list = lists.value(id, NULL);
-        if (list)
-        {
+    if (uas) {
+        WaypointList* list = _lists.value(uas, NULL);
+        if (list) {
             delete list;
-            lists.remove(id);
+            _lists.remove(uas);
         }
     }
 }
 
-void QGCWaypointListMulti::systemCreated(UASInterface* uas)
+void QGCWaypointListMulti::_systemCreated(UASInterface* uas)
 {
-    WaypointList* list = new WaypointList(ui->stackedWidget, uas->getWaypointManager());
-    lists.insert(uas->getUASID(), list);
-    ui->stackedWidget->addWidget(list);
+    WaypointList* list = new WaypointList(_ui->stackedWidget, uas->getWaypointManager());
+    _lists.insert(uas, list);
+    _ui->stackedWidget->addWidget(list);
     // Ensure widget is deleted when system is deleted
-    connect(uas, SIGNAL(destroyed(QObject*)), this, SLOT(systemDeleted(QObject*)));
+    connect(uas, &QObject::destroyed, this, &QGCWaypointListMulti::_systemDeleted);
 }
 
-void QGCWaypointListMulti::systemSetActive(UASInterface* uas)
+void QGCWaypointListMulti::_systemSetActive(UASInterface* uas)
 {
-    WaypointList* list = lists.value(uas->getUASID(), NULL);
+    WaypointList* list = _lists.value(uas, NULL);
     if (list) {
-        ui->stackedWidget->setCurrentWidget(list);
+        _ui->stackedWidget->setCurrentWidget(list);
     }
 }
 
-QGCWaypointListMulti::~QGCWaypointListMulti()
-{
-    delete ui;
-}
-
 void QGCWaypointListMulti::changeEvent(QEvent *e)
 {
     QWidget::changeEvent(e);
     switch (e->type()) {
     case QEvent::LanguageChange:
-        ui->retranslateUi(this);
+        _ui->retranslateUi(this);
         break;
     default:
         break;

src/ui/QGCWaypointListMulti.h

@@ -20,18 +20,20 @@ public:
     explicit QGCWaypointListMulti(QWidget *parent = 0);
     ~QGCWaypointListMulti();
 
-public slots:
-    void systemDeleted(QObject* uas);
-    void systemCreated(UASInterface* uas);
-    void systemSetActive(UASInterface* uas);
-
 protected:
-    quint16 offline_uas_id;
-    void changeEvent(QEvent *e);
-    QMap<int, WaypointList*> lists;
+    // Override from Widget
+    virtual void changeEvent(QEvent *e);
+    
+private slots:
+    void _systemDeleted(QObject* uas);
+    void _systemCreated(UASInterface* uas);
+    void _systemSetActive(UASInterface* uas);
 
 private:
-    Ui::QGCWaypointListMulti *ui;
+    
+    static void*                _offlineUAS;
+    QMap<void*, WaypointList*>  _lists;
+    Ui::QGCWaypointListMulti*   _ui;
 };
 
 #endif // QGCWAYPOINTLISTMULTI_H