init

Telegram/lib_base/base/weak_qptr.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 "base/basic_types.h"
+
+#include <QObject>
+#include <QPointer>
+
+#include <atomic>
+#include <memory>
+
+template <typename T>
+class object_ptr;
+
+namespace base {
+
+template <typename T>
+class weak_qptr {
+public:
+	weak_qptr() = default;
+	weak_qptr(std::nullptr_t) noexcept {
+	}
+	template <
+		typename Other,
+		typename = std::enable_if_t<std::is_base_of_v<T, Other>>>
+	weak_qptr(Other *value) noexcept
+	: _object(static_cast<const QObject*>(value)) {
+	}
+	template <
+		typename Other,
+		typename = std::enable_if_t<std::is_base_of_v<T, Other>>>
+	weak_qptr(const QPointer<Other> &value) noexcept
+	: weak_qptr(value.data()) {
+	}
+	template <
+		typename Other,
+		typename = std::enable_if_t<std::is_base_of_v<T, Other>>>
+	weak_qptr(gsl::not_null<Other*> value) noexcept
+	: weak_qptr(value.get()) {
+	}
+	template <
+		typename Other,
+		typename = std::enable_if_t<std::is_base_of_v<T, Other>>>
+	weak_qptr(const std::unique_ptr<Other> &value) noexcept
+	: weak_qptr(value.get()) {
+	}
+	template <
+		typename Other,
+		typename = std::enable_if_t<std::is_base_of_v<T, Other>>>
+	weak_qptr(const std::shared_ptr<Other> &value) noexcept
+	: weak_qptr(value.get()) {
+	}
+	template <
+		typename Other,
+		typename = std::enable_if_t<std::is_base_of_v<T, Other>>>
+	weak_qptr(const std::weak_ptr<Other> &value) noexcept
+	: weak_qptr(value.lock().get()) {
+	}
+	template <
+		typename Other,
+		typename = std::enable_if_t<std::is_base_of_v<T, Other>>>
+	weak_qptr(const weak_qptr<Other> &other) noexcept
+	: _object(other._object) {
+	}
+	template <
+		typename Other,
+		typename = std::enable_if_t<std::is_base_of_v<T, Other>>>
+	weak_qptr(weak_qptr<Other> &&other) noexcept
+	: _object(std::move(other._object)) {
+	}
+
+	template <
+		typename Other,
+		typename = std::enable_if_t<std::is_base_of_v<T, Other>>>
+	weak_qptr &operator=(Other *value) noexcept {
+		reset(value);
+		return *this;
+	}
+	template <
+		typename Other,
+		typename = std::enable_if_t<std::is_base_of_v<T, Other>>>
+	weak_qptr &operator=(const QPointer<Other> &value) noexcept {
+		reset(value.data());
+		return *this;
+	}
+	template <
+		typename Other,
+		typename = std::enable_if_t<std::is_base_of_v<T, Other>>>
+	weak_qptr &operator=(gsl::not_null<Other*> value) noexcept {
+		reset(value.get());
+		return *this;
+	}
+	template <
+		typename Other,
+		typename = std::enable_if_t<std::is_base_of_v<T, Other>>>
+	weak_qptr &operator=(const std::unique_ptr<Other> &value) noexcept {
+		reset(value.get());
+		return *this;
+	}
+	template <
+		typename Other,
+		typename = std::enable_if_t<std::is_base_of_v<T, Other>>>
+	weak_qptr &operator=(const std::shared_ptr<Other> &value) noexcept {
+		reset(value.get());
+		return *this;
+	}
+	template <
+		typename Other,
+		typename = std::enable_if_t<std::is_base_of_v<T, Other>>>
+	weak_qptr &operator=(const std::weak_ptr<Other> &value) noexcept {
+		reset(value.lock().get());
+		return *this;
+	}
+	template <
+		typename Other,
+		typename = std::enable_if_t<std::is_base_of_v<T, Other>>>
+	weak_qptr &operator=(const weak_qptr<Other> &other) noexcept {
+		_object = other._object;
+		return *this;
+	}
+	template <
+		typename Other,
+		typename = std::enable_if_t<std::is_base_of_v<T, Other>>>
+	weak_qptr &operator=(weak_qptr<Other> &&other) noexcept {
+		_object = std::move(other._object);
+		return *this;
+	}
+
+	[[nodiscard]] bool null() const noexcept {
+		return _object.isNull();
+	}
+	[[nodiscard]] bool empty() const noexcept {
+		return !_object;
+	}
+	[[nodiscard]] T *get() const noexcept {
+		const auto strong = _object.data();
+		if constexpr (std::is_const_v<T>) {
+			return static_cast<T*>(strong);
+		} else {
+			return const_cast<T*>(static_cast<const T*>(strong));
+		}
+	}
+	[[nodiscard]] explicit operator bool() const noexcept {
+		return !empty();
+	}
+	[[nodiscard]] T &operator*() const noexcept {
+		return *get();
+	}
+	[[nodiscard]] T *operator->() const noexcept {
+		return get();
+	}
+
+	friend inline auto operator<=>(
+		weak_qptr,
+		weak_qptr) noexcept = default;
+
+	void reset(T *value = nullptr) noexcept {
+		_object = static_cast<const QObject*>(value);
+	}
+
+private:
+	template <typename U>
+	friend class weak_qptr;
+
+	QPointer<const QObject> _object;
+
+};
+
+template <typename T>
+inline bool operator==(const weak_qptr<T> &pointer, std::nullptr_t) noexcept {
+	return (pointer.get() == nullptr);
+}
+
+template <typename T>
+inline bool operator==(std::nullptr_t, const weak_qptr<T> &pointer) noexcept {
+	return (pointer == nullptr);
+}
+
+template <typename T>
+inline bool operator!=(const weak_qptr<T> &pointer, std::nullptr_t) noexcept {
+	return !(pointer == nullptr);
+}
+
+template <typename T>
+inline bool operator!=(std::nullptr_t, const weak_qptr<T> &pointer) noexcept {
+	return !(pointer == nullptr);
+}
+
+template <
+	typename T,
+	typename = std::enable_if_t<std::is_base_of_v<QObject, T>>>
+weak_qptr<T> make_weak(T *value) {
+	return value;
+}
+
+template <
+	typename T,
+	typename = std::enable_if_t<std::is_base_of_v<QObject, T>>>
+weak_qptr<T> make_weak(gsl::not_null<T*> value) {
+	return value;
+}
+
+template <
+	typename T,
+	typename = std::enable_if_t<std::is_base_of_v<QObject, T>>>
+weak_qptr<T> make_weak(const std::unique_ptr<T> &value) {
+	return value;
+}
+
+template <
+	typename T,
+	typename = std::enable_if_t<std::is_base_of_v<QObject, T>>>
+weak_qptr<T> make_weak(const std::shared_ptr<T> &value) {
+	return value;
+}
+
+template <
+	typename T,
+	typename = std::enable_if_t<std::is_base_of_v<QObject, T>>>
+weak_qptr<T> make_weak(const std::weak_ptr<T> &value) {
+	return value;
+}
+
+template <typename T>
+weak_qptr<T> make_weak(const object_ptr<T> &value) {
+	return value.data();
+}
+
+} // namespace base
+
+namespace crl {
+
+template <typename T, typename Enable>
+struct guard_traits;
+
+template <typename T>
+struct guard_traits<base::weak_qptr<T>, void> {
+	static base::weak_qptr<T> create(const base::weak_qptr<T> &value) {
+		return value;
+	}
+	static base::weak_qptr<T> create(base::weak_qptr<T> &&value) {
+		return std::move(value);
+	}
+	static bool check(const base::weak_qptr<T> &guard) {
+		return guard.get() != nullptr;
+	}
+
+};
+
+} // namespace crl