UI updates

- add import dialog
  this is more complex than I thought
- added scope exit
  grammar sugar
- main dialog is now linked to import dialog
- importer citra file path is fixed
- importer now reports maximum size
- file util is improved with GetDirectoryTreeSize

src/frontend/import_dialog.h

@@ -0,0 +1,41 @@
+// Copyright 2019 threeSD Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <memory>
+#include <string>
+#include <vector>
+#include <QDialog>
+#include "core/importer.h"
+
+class QTreeWidgetItem;
+
+namespace Ui {
+class ImportDialog;
+}
+
+class ImportDialog : public QDialog {
+    Q_OBJECT;
+
+public:
+    explicit ImportDialog(QWidget* parent, const Core::Config& config);
+    ~ImportDialog() override;
+
+private:
+    void PopulateContent();
+    void UpdateSizeDisplay();
+    void UpdateItemCheckState(QTreeWidgetItem* item);
+
+    std::unique_ptr<Ui::ImportDialog> ui;
+
+    std::string user_path;
+    Core::SDMCImporter importer;
+    std::vector<Core::ContentSpecifier> contents;
+    u64 total_size = 0;
+
+    // HACK: To tell whether the checkbox state change is a programmatic trigger
+    // TODO: Is there a more elegant way of doing the same?
+    bool program_trigger = false;
+};