feat: implement soft reloading

src/cpp/shell.hpp

@@ -1,26 +1,37 @@
 #pragma once
 
 #include <qcontainerfwd.h>
+#include <qlist.h>
 #include <qlogging.h>
 #include <qobject.h>
 #include <qqmlengine.h>
 #include <qqmllist.h>
 #include <qtmetamacros.h>
 
-class QtShell: public QObject {
+#include "scavenge.hpp"
+
+class QtShell: public Scavenger, virtual public Scavengeable {
 	Q_OBJECT;
 	Q_PROPERTY(QQmlListProperty<QObject> components READ components FINAL);
 	Q_CLASSINFO("DefaultProperty", "components");
 	QML_ELEMENT;
 
 public:
-	explicit QtShell(QObject* parent = nullptr): QObject(parent) {}
+	explicit QtShell(QObject* parent = nullptr): Scavenger(parent) {}
+
+	void earlyInit(QObject* old) override;
+	QObject* scavengeTargetFor(QObject* child) override;
 
 	QQmlListProperty<QObject> components();
 
 public slots:
-	void reload();
+	void reload(bool hard = true);
 
 private:
 	static void appendComponent(QQmlListProperty<QObject>* list, QObject* component);
+
+public:
+	// track only the children assigned to `components` in order
+	QList<QObject*> children;
+	QList<QObject*> scavengeableChildren;
 };