Crash fix

Two fixes really:
1. fix some parent pointers being wrong
2. fix notebooks being destroyed while node tree is still valid

main.cpp

@@ -45,12 +45,13 @@ int main (int argc, char* argv[]) {
 	using std::string_view;
 
 	QApplication app(argc, argv);
-	duck::MainWindow win;
-	win.show();
 
-	std::vector<duck::Node> roots = duck::build_notebook_tree(BASE_PATH);
+	duck::Notebooks notebooks(BASE_PATH);
+	std::vector<duck::Node> roots = notebooks.build_tree();
 	std::vector<const duck::NotebookInfo*> dele_list = duck::make_list_of_deleted(roots);
 
+	duck::MainWindow win(&roots.back());
+	win.show();
 	for (const duck::NotebookInfo* nb : dele_list) {
 		for (const auto& f : nb->files) {
 			std::cout << "/home/root/.local/share/remarkable/xochitl/" << f << '\n';

notebook_tree.cpp

@@ -21,6 +21,7 @@
 #include <stdexcept>
 #include <filesystem>
 #include <simdjson.h>
+#include <cassert>
 
 namespace fs = std::filesystem;
 
@@ -69,6 +70,17 @@ NotebookMapType build_notebook_infos (
 	return retval;
 }
 
+void assert_parents_correct (const Node* node) {
+#if !defined(NDEBUG)
+	for (const auto& child : node->children) {
+		assert(child.parent == node);
+		assert_parents_correct(&child);
+	}
+#else
+	static_cast<void>(node);
+#endif
+}
+
 std::vector<Node> to_tree (const NotebookMapType& nbs) {
 	std::unordered_map<std::string_view, std::pair<unsigned int, Node>> parents;
 	for (const auto& nb : nbs) {
@@ -102,15 +114,27 @@ std::vector<Node> to_tree (const NotebookMapType& nbs) {
 		if (node.info) {
 			auto it_parent = parents.find(node.info->parent);
 			Node* dst_node = (parents.end() == it_parent ? grouped_nodes[node.info->parent] : &it_parent->second.second);
+			node.parent = dst_node;
+			assert(dst_node->children.capacity() > dst_node->children.size());
 			dst_node->children.push_back(std::move(node));
+			for (auto& child : dst_node->children.back().children) {
+				child.parent = &dst_node->children.back();
+			}
 			grouped_nodes[dst_node->children.back().name] = &dst_node->children.back();
 		}
 		else {
+			node.parent = nullptr;
 			roots.push_back(std::move(node));
 			grouped_nodes[node.name] = &roots.back();
 		}
 	}
 
+	for (auto& root : roots) {
+		for (auto& child : root.children) {
+			child.parent = &root;
+		}
+	}
+
 	return roots;
 }
 
@@ -136,9 +160,24 @@ std::vector<const NotebookInfo*> make_dele_list (const Node& tree) {
 }
 } //unnamed namespace
 
-std::vector<Node> build_notebook_tree (std::string_view base_path) {
-	auto notebooks = build_notebook_infos(base_path);
-	return to_tree(notebooks);
+struct Notebooks::LocalData {
+	NotebookMapType nb_map;
+};
+
+Notebooks::Notebooks (std::string_view base_path) :
+	m_local(std::make_unique<LocalData>())
+{
+	m_local->nb_map = build_notebook_infos(base_path);
+}
+
+Notebooks::~Notebooks() noexcept = default;
+
+std::vector<Node> Notebooks::build_tree() const {
+	auto tree = to_tree(m_local->nb_map);
+	for (const auto& root : tree) {
+		assert_parents_correct(&root);
+	}
+	return tree; //to_tree(m_local->nb_map);
 }
 
 std::vector<const NotebookInfo*> make_list_of_deleted (const std::vector<Node>& roots) {

notebook_tree.hpp

@@ -21,6 +21,7 @@
 #include <cstdint>
 #include <string>
 #include <string_view>
+#include <memory>
 
 namespace duck {
 struct NotebookInfo {
@@ -40,6 +41,12 @@ struct Node {
 		parent(nullptr)
 	{ }
 
+	Node (const Node&) = delete;
+	Node (Node&& other) = default;
+
+	Node& operator= (const Node&) = delete;
+	Node& operator= (Node&&) = default;
+
 	Node (std::string_view name, const NotebookInfo* payload, Node* parent) :
 		name(name),
 		info(payload),
@@ -52,6 +59,18 @@ struct Node {
 	const Node* parent;
 };
 
-std::vector<Node> build_notebook_tree (std::string_view base_path);
+class Notebooks {
+public:
+	Notebooks (std::string_view base_path);
+	~Notebooks() noexcept;
+
+	std::vector<Node> build_tree() const;
+
+private:
+	struct LocalData;
+
+	std::unique_ptr<LocalData> m_local;
+};
+
 std::vector<const NotebookInfo*> make_list_of_deleted (const std::vector<Node>& roots);
 } //namespace duck