init

Telegram/lib_rpl/rpl/lifetime.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/unique_function.h"
+#include <vector>
+
+namespace rpl {
+namespace details {
+
+template <typename Type>
+inline Type take(Type &value) {
+	return std::exchange(value, Type{});
+}
+
+} // namespace details
+
+class lifetime {
+public:
+	lifetime() = default;
+	lifetime(lifetime &&other);
+	lifetime &operator=(lifetime &&other);
+	~lifetime() { destroy(); }
+
+	template <typename Destroy, typename = decltype(std::declval<Destroy>()())>
+	lifetime(Destroy &&destroy);
+
+	explicit operator bool() const { return !_callbacks.empty(); }
+
+	template <typename Destroy, typename = decltype(std::declval<Destroy>()())>
+	void add(Destroy &&destroy);
+	void add(lifetime &&other);
+	void destroy();
+
+	void release();
+
+	template <typename Type, typename... Args>
+	Type *make_state(Args&& ...args) {
+		const auto result = new Type(std::forward<Args>(args)...);
+		add([=] {
+			static_assert(sizeof(Type) > 0, "Can't delete unknown type.");
+			delete result;
+		});
+		return result;
+	}
+
+private:
+	std::vector<base::unique_function<void()>> _callbacks;
+
+};
+
+inline lifetime::lifetime(lifetime &&other)
+: _callbacks(details::take(other._callbacks)) {
+}
+
+inline lifetime &lifetime::operator=(lifetime &&other) {
+	std::swap(_callbacks, other._callbacks);
+	other.destroy();
+	return *this;
+}
+
+template <typename Destroy, typename>
+inline lifetime::lifetime(Destroy &&destroy) {
+	_callbacks.emplace_back(std::forward<Destroy>(destroy));
+}
+
+template <typename Destroy, typename>
+inline void lifetime::add(Destroy &&destroy) {
+	_callbacks.emplace_back(std::forward<Destroy>(destroy));
+}
+
+inline void lifetime::add(lifetime &&other) {
+	auto callbacks = details::take(other._callbacks);
+	_callbacks.insert(
+		_callbacks.end(),
+		std::make_move_iterator(callbacks.begin()),
+		std::make_move_iterator(callbacks.end()));
+}
+
+inline void lifetime::destroy() {
+	auto callbacks = details::take(_callbacks);
+	for (auto i = callbacks.rbegin(), e = callbacks.rend(); i != e; ++i) {
+		(*i)();
+	}
+}
+
+inline void lifetime::release() {
+	_callbacks.clear();
+}
+
+} // namespace rpl