init

Telegram/lib_base/base/object_ptr.h

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+// This file is part of Desktop App Toolkit,
+// a set of libraries for developing nice desktop applications.
+//
+// For license and copyright information please follow this link:
+// https://github.com/desktop-app/legal/blob/master/LEGAL
+//
+#pragma once
+
+#include <QtCore/QPointer>
+
+// Smart pointer for QObject*, has move semantics, destroys object if it doesn't have a parent.
+template <typename Object>
+class object_ptr {
+public:
+	object_ptr(std::nullptr_t) noexcept {
+	}
+
+	// No default constructor, but constructors with at least
+	// one argument are simply make functions.
+	template <typename Parent, typename... Args>
+	explicit object_ptr(Parent &&parent, Args&&... args)
+	: _object(new Object(std::forward<Parent>(parent), std::forward<Args>(args)...)) {
+	}
+	static object_ptr<Object> fromRaw(Object *value) noexcept {
+		object_ptr<Object> result = { nullptr };
+		result._object = value;
+		return result;
+	}
+	Object *release() noexcept {
+		return static_cast<Object*>(base::take(_object).data());
+	}
+
+	object_ptr(const object_ptr &other) = delete;
+	object_ptr &operator=(const object_ptr &other) = delete;
+	object_ptr(object_ptr &&other) noexcept : _object(base::take(other._object)) {
+	}
+	object_ptr &operator=(object_ptr &&other) noexcept {
+		auto temp = std::move(other);
+		destroy();
+		std::swap(_object, temp._object);
+		return *this;
+	}
+
+	template <
+		typename OtherObject,
+		typename = std::enable_if_t<
+			std::is_base_of_v<Object, OtherObject>>>
+	object_ptr(object_ptr<OtherObject> &&other) noexcept
+	: _object(base::take(other._object)) {
+	}
+
+	template <
+		typename OtherObject,
+		typename = std::enable_if_t<
+			std::is_base_of_v<Object, OtherObject>>>
+	object_ptr &operator=(object_ptr<OtherObject> &&other) noexcept {
+		_object = base::take(other._object);
+		return *this;
+	}
+
+	object_ptr &operator=(std::nullptr_t) noexcept {
+		_object = nullptr;
+		return *this;
+	}
+
+	Object *get() const noexcept {
+		return static_cast<Object*>(_object.data());
+	}
+
+	// So we can pass this pointer to methods like connect().
+	Object *data() const noexcept {
+		return get();
+	}
+	operator Object*() const noexcept {
+		return get();
+	}
+
+	explicit operator bool() const noexcept {
+		return _object.data() != nullptr;
+	}
+
+	Object *operator->() const noexcept {
+		return get();
+	}
+	Object &operator*() const noexcept {
+		return *get();
+	}
+
+	// Use that instead "= new Object(parent, ...)"
+	template <typename Parent, typename... Args>
+	Object *create(Parent &&parent, Args&&... args) {
+		destroy();
+		_object = new Object(
+			std::forward<Parent>(parent),
+			std::forward<Args>(args)...);
+		return get();
+	}
+	void destroy() noexcept {
+		delete base::take(_object);
+	}
+	void destroyDelayed() {
+		if (_object) {
+			if (auto widget = base::up_cast<QWidget*>(get())) {
+				widget->hide();
+			}
+			base::take(_object)->deleteLater();
+		}
+	}
+
+	~object_ptr() noexcept {
+		if (auto pointer = _object) {
+			if (!pointer->parent()) {
+				destroy();
+			}
+		}
+	}
+
+private:
+	template <typename OtherObject>
+	friend class object_ptr;
+
+	QPointer<QObject> _object;
+
+};