Introduce ViewGuard: A weak ptr to View

src/ViewGuard.cpp

@@ -0,0 +1,57 @@
+#include "ViewGuard.h"
+#include "View.h"
+
+using namespace KDDockWidgets;
+
+ViewGuard::ViewGuard(View *view)
+    : v(view && view->inDtor() ? nullptr : view)
+{
+    if (v) {
+        m_onDestroy = v->beingDestroyed.connect([this] {
+            v = nullptr;
+        });
+    }
+}
+
+ViewGuard::operator bool() const
+{
+    return !isNull();
+}
+
+bool ViewGuard::isNull() const
+{
+    return v == nullptr;
+}
+
+View *ViewGuard::operator->()
+{
+    return v;
+}
+
+void ViewGuard::clear()
+{
+    v = nullptr;
+}
+
+View *ViewGuard::view() const
+{
+    return v;
+}
+
+ViewGuard& ViewGuard::operator=(View *view)
+{
+    if (view == v) {
+        return *this;
+    }
+
+    // Remove the pervious connection
+    if (m_onDestroy.isActive())
+        m_onDestroy.disconnect();
+
+    v = view;
+
+    m_onDestroy = v->beingDestroyed.connect([this] {
+        v = nullptr;
+    });
+    return *this;
+}