use a factory

ui/CMakeLists.txt

@@ -1,7 +1,6 @@
 include(impl.cmake)
 
 qt_add_executable(PROJECT-NAME
-	src/api.cxx
 	src/main.cxx
 	src/main_window.cxx
 	src/main_window.ui

ui/src/api.cxx

@@ -1,16 +0,0 @@
-#include "api.hxx"
-
-#include <stdexcept>
-#include <utility>
-
-namespace ffi {
-extern "C" ICore* rt4_viewport_create(xcb_connection_t* connection, std::uint32_t window, std::uint32_t width, std::uint32_t height);
-} // namespace ffi
-
-BoxCore BoxCore::from_xcb(xcb_connection_t* connection, std::uint32_t window, std::uint32_t width, std::uint32_t height) {
-	if (!connection)
-		throw std::logic_error("attempt to use a null connection");
-	if (!window)
-		throw std::logic_error("attempt to use a null window");
-	return BoxCore{ffi::rt4_viewport_create(connection, window, width, height)};
-}

ui/src/api.hxx

@@ -10,7 +10,6 @@ class IBoxed {
 	friend struct BoxDeleter;
 
 private:
-	~IBoxed() = delete;
 	virtual void destroy() = 0;
 };
 
@@ -44,8 +43,12 @@ public:
 	virtual void redraw(const RedrawArgs& args) = 0;
 };
 
-class BoxCore : public Box<ICore> {
+class ICoreFactory : public IBoxed {
+private:
+	virtual ICore* new_xcb(xcb_connection_t* connection, std::uint32_t window, std::uint32_t width, std::uint32_t height) const = 0;
+
 public:
-	using Box<ICore>::Box;
-	static BoxCore from_xcb(xcb_connection_t* connection, std::uint32_t window, std::uint32_t width, std::uint32_t height);
+	Box<ICore> from_xcb(xcb_connection_t* connection, std::uint32_t window, std::uint32_t width, std::uint32_t height) const {
+		return Box<ICore>{new_xcb(connection, window, width, height)};
+	}
 };

ui/src/main.cxx

@@ -1,15 +1,31 @@
-#include "main_window.hxx"
-
 #include <QApplication>
 
-int main(int argc, char* argv[]) {
+#include "api.hxx"
+#include "main_window.hxx"
+
+extern "C" int run(int argc, char* argv[], ICoreFactory* factory) {
 	// only X11 is supported so, use XCB unless overriden
 	setenv("QT_QPA_PLATFORM", "xcb", 0);
 
 	QApplication app(argc, argv);
 
-	auto w = new PROJECTNAME;
+	auto w = new PROJECTNAME(factory);
 	w->show();
 
 	return app.exec();
 }
+
+extern "C" ICore* rt4_viewport_create(xcb_connection_t* connection, std::uint32_t window, std::uint32_t width, std::uint32_t height);
+
+class CoreFactory : public ICoreFactory {
+public:
+	void destroy() override {}
+	ICore* new_xcb(xcb_connection_t* connection, std::uint32_t window, std::uint32_t width, std::uint32_t height) const override {
+		return rt4_viewport_create(connection, window, width, height);
+	}
+};
+
+int main(int argc, char* argv[]) {
+	CoreFactory factory;
+	return run(argc, argv, &factory);
+}

ui/src/main_window.cxx

@@ -2,10 +2,12 @@
 
 #include "ui_main_window.h"
 
-PROJECTNAME::PROJECTNAME(QWidget* parent)
+PROJECTNAME::PROJECTNAME(const ICoreFactory* factory, QWidget* parent)
 	: QMainWindow(parent),
-	  m_ui(new Ui::MainWindow) {
+	  m_ui(new Ui::MainWindow),
+	  factory(factory) {
 	m_ui->setupUi(this);
+	m_ui->viewport->setFactory(factory);
 	updateView();
 }
 

ui/src/main_window.hxx

@@ -3,6 +3,8 @@
 
 #include <memory>
 
+#include "api.hxx"
+
 namespace Ui {
 class MainWindow;
 }
@@ -11,7 +13,7 @@ class PROJECTNAME : public QMainWindow {
 	Q_OBJECT
 
 public:
-	explicit PROJECTNAME(QWidget* parent = nullptr);
+	explicit PROJECTNAME(const ICoreFactory* factory, QWidget* parent = nullptr);
 	~PROJECTNAME() override;
 
 public slots:
@@ -19,4 +21,5 @@ public slots:
 
 private:
 	const std::unique_ptr<Ui::MainWindow> m_ui;
+	const ICoreFactory* factory;
 };

ui/src/viewport.cxx

@@ -14,6 +14,11 @@ Viewport::Viewport(QWidget* parent, Qt::WindowFlags f)
 
 Viewport::~Viewport() = default;
 
+void Viewport::setFactory(const ICoreFactory* new_factory) {
+	factory = new_factory;
+	update();
+}
+
 void Viewport::setView(RedrawArgs new_args) {
 	args = new_args;
 	update();
@@ -37,6 +42,8 @@ bool Viewport::event(QEvent* event) {
 void Viewport::paintEvent(QPaintEvent* event) {
 	if (!core)
 		recreate();
+	if (!core)
+		return;
 	core->redraw(args);
 }
 
@@ -48,6 +55,9 @@ void Viewport::resizeEvent(QResizeEvent* event) {
 }
 
 void Viewport::recreate() try {
+	if (!factory)
+		return;
+
 	auto* app = qobject_cast<QGuiApplication*>(QApplication::instance());
 	if (!app)
 		throw std::runtime_error("not a GUI application (WTF?)");
@@ -59,11 +69,9 @@ void Viewport::recreate() try {
 	auto* xcb_connection = native->connection();
 	std::uint32_t x11_window = winId();
 
-	fprintf(stderr, "connection %p, window %#08x\n", xcb_connection, x11_window);
-
 	const QSize device_size = size() * devicePixelRatio();
 	core.reset();
-	core = BoxCore::from_xcb(xcb_connection, x11_window, device_size.width(), device_size.height());
+	core = factory->from_xcb(xcb_connection, x11_window, device_size.width(), device_size.height());
 } catch (const std::exception& e) {
 	fprintf(stderr, "failed to recreate the viewport: %s", e.what());
 }

ui/src/viewport.hxx

@@ -12,6 +12,7 @@ public:
 	~Viewport() override;
 	QPaintEngine* paintEngine() const override;
 
+	void setFactory(const ICoreFactory* new_factory);
 	void setView(RedrawArgs new_args);
 
 protected:
@@ -20,7 +21,8 @@ protected:
 	void resizeEvent(QResizeEvent* event) override;
 
 private:
-	BoxCore core;
+	const ICoreFactory* factory = nullptr;
+	Box<ICore> core;
 	RedrawArgs args = {};
 
 	void recreate();