// // Copyright Aliaksei Levin (levlam@telegram.org), Arseny Smirnov (arseny30@gmail.com) 2014-2018 // // Distributed under the Boost Software License, Version 1.0. (See accompanying // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) // #pragma once #include "td/utils/common.h" #include <cstdlib> #include <memory> #include <type_traits> #include <utility> namespace td { class Guard { public: Guard() = default; Guard(const Guard &other) = delete; Guard &operator=(const Guard &other) = delete; Guard(Guard &&other) = default; Guard &operator=(Guard &&other) = default; virtual ~Guard() = default; virtual void dismiss() { std::abort(); } }; template <class FunctionT> class LambdaGuard : public Guard { public: explicit LambdaGuard(const FunctionT &func) : func_(func) { } explicit LambdaGuard(FunctionT &&func) : func_(std::move(func)) { } LambdaGuard(const LambdaGuard &other) = delete; LambdaGuard &operator=(const LambdaGuard &other) = delete; LambdaGuard(LambdaGuard &&other) : func_(std::move(other.func_)), dismissed_(other.dismissed_) { other.dismissed_ = true; } LambdaGuard &operator=(LambdaGuard &&other) = delete; void dismiss() { dismissed_ = true; } ~LambdaGuard() { if (!dismissed_) { func_(); } } private: FunctionT func_; bool dismissed_ = false; }; template <class F> unique_ptr<Guard> create_lambda_guard(F &&f) { return make_unique<LambdaGuard<F>>(std::forward<F>(f)); } template <class F> std::shared_ptr<Guard> create_shared_lambda_guard(F &&f) { return std::make_shared<LambdaGuard<F>>(std::forward<F>(f)); } enum class ScopeExit {}; template <class FunctionT> auto operator+(ScopeExit, FunctionT &&func) { return LambdaGuard<std::decay_t<FunctionT>>(std::forward<FunctionT>(func)); } } // namespace td #define SCOPE_EXIT auto TD_CONCAT(SCOPE_EXIT_VAR_, __LINE__) = ::td::ScopeExit() + [&]()