| // unique_resource |
| // Copyright (c) 2015 okdshin |
| // Distributed under the Boost Software License, Version 1.0. (See accompanying |
| // file LICENSE.txt or copy at http://www.boost.org/LICENSE_1_0.txt) |
| // This implementation is based on C++ standards committee paper N4189. |
| #ifndef UNIQUE_RESOURCE_H_ |
| #define UNIQUE_RESOURCE_H_ |
| #include <utility> |
| // workaround for GCC |
| #if defined(__GNUC__) |
| #ifdef UNIQUE_RESOURCE_ALLOW_DELETER_CALL_THROWING_EXCEPTION |
| #define UNIQUE_RESOURCE_NOEXCEPT |
| #else |
| #define UNIQUE_RESOURCE_NOEXCEPT noexcept |
| #endif |
| #define UNIQUE_RESOURCE_NOEXCEPT_NOEXCEPT_THIS_RESET UNIQUE_RESOURCE_NOEXCEPT |
| #define UNIQUE_RESOURCE_NOEXCEPT_NOEXCEPT_THIS_DELETER_CALL \ |
| UNIQUE_RESOURCE_NOEXCEPT |
| #else |
| #define UNIQUE_RESOURCE_NOEXCEPT_NOEXCEPT_THIS_RESET \ |
| noexcept(noexcept(this->reset())) |
| #define UNIQUE_RESOURCE_NOEXCEPT_NOEXCEPT_THIS_DELETER_CALL \ |
| noexcept(noexcept(this->get_deleter()(resource))) |
| #endif |
| namespace std_experimental { |
| template <typename R, typename D> class unique_resource { |
| R resource; |
| D deleter; |
| bool execute_on_destruction; // exposition only |
| unique_resource &operator=(unique_resource const &) = delete; |
| unique_resource(unique_resource const &) = delete; // no copies! |
| public: |
| // construction |
| explicit unique_resource(R &&resource_, D &&deleter_, |
| bool shouldrun = true) noexcept |
| : resource(std::move(resource_)), |
| deleter(std::move(deleter_)), |
| execute_on_destruction{shouldrun} {} |
| // move |
| unique_resource(unique_resource &&other) noexcept |
| : resource(std::move(other.resource)), |
| deleter(std::move(other.deleter)), |
| execute_on_destruction{other.execute_on_destruction} { |
| other.release(); |
| } |
| unique_resource &operator=(unique_resource &&other) |
| UNIQUE_RESOURCE_NOEXCEPT_NOEXCEPT_THIS_RESET { |
| this->reset(); |
| this->deleter = std::move(other.deleter); |
| this->resource = std::move(other.resource); |
| this->execute_on_destruction = other.execute_on_destruction; |
| other.release(); |
| return *this; |
| } |
| // resource release |
| ~unique_resource() UNIQUE_RESOURCE_NOEXCEPT_NOEXCEPT_THIS_RESET { |
| this->reset(); |
| } |
| void reset() UNIQUE_RESOURCE_NOEXCEPT_NOEXCEPT_THIS_DELETER_CALL { |
| if (execute_on_destruction) { |
| this->execute_on_destruction = false; |
| this->get_deleter()(resource); |
| } |
| } |
| void reset(R &&newresource) UNIQUE_RESOURCE_NOEXCEPT_NOEXCEPT_THIS_RESET { |
| this->reset(); |
| this->resource = std::move(newresource); |
| this->execute_on_destruction = true; |
| } |
| R const &release() noexcept { |
| this->execute_on_destruction = false; |
| return this->get(); |
| } |
| // resource access |
| R const &get() const noexcept { return this->resource; } |
| operator R const &() const noexcept { return this->resource; } |
| R operator->() const noexcept { return this->resource; } |
| typename std::add_lvalue_reference< |
| typename std::remove_pointer<R>::type>::type |
| operator*() const { |
| return *this->resource; |
| } |
| // deleter access |
| const D &get_deleter() const noexcept { return this->deleter; } |
| }; |
| // factories |
| template <typename R, typename D> |
| unique_resource<R, typename std::remove_reference<D>::type> |
| make_unique_resource(R &&r, D &&d) noexcept { |
| return unique_resource<R, typename std::remove_reference<D>::type>( |
| std::move(r), std::forward<typename std::remove_reference<D>::type>(d), |
| true); |
| } |
| template <typename R, typename D> |
| unique_resource<R, D> make_unique_resource_checked(R r, R invalid, |
| D d) noexcept { |
| bool shouldrun = not bool(r == invalid); |
| return unique_resource<R, D>(std::move(r), std::move(d), shouldrun); |
| } |
| } |
| #endif /* UNIQUE_RESOURCE_H_ */ |