scope.hpp

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#ifndef NEFORCE_CORE_UTILITY_SCOPE_HPP__
#define NEFORCE_CORE_UTILITY_SCOPE_HPP__

 
#include "NeForce/core/exception/exception.hpp"
#include "NeForce/core/numeric/numeric_traits.hpp"
#include "NeForce/core/utility/compressed_pair.hpp"
NEFORCE_BEGIN_NAMESPACE__


template <typename Func>
class scope_exit {
private:
    compressed_pair<Func, bool> func_pair_; 
 
public:
    template <typename F, enable_if_t<!is_same_v<remove_cvref_t<F>, scope_exit> && is_constructible_v<Func, F> &&
                                              !is_nothrow_constructible_v<Func, F>,
                                      int> = 0>
    explicit scope_exit(F&& func) try :
    func_pair_(exact_arg_construct_tag{}, _NEFORCE forward<F>(func), true) {
    } catch (...) {
        func();
    }

    template <typename F, enable_if_t<!is_same_v<remove_cvref_t<F>, scope_exit> && is_constructible_v<Func, F> &&
                                              is_nothrow_constructible_v<Func, F>,
                                      int> = 0>
    explicit scope_exit(F&& func) noexcept :
    func_pair_(exact_arg_construct_tag{}, _NEFORCE forward<F>(func), true) {}
 
    scope_exit(const scope_exit&) = delete;
    scope_exit& operator=(const scope_exit&) = delete;

    scope_exit(scope_exit&& rhs) noexcept(is_nothrow_move_constructible_v<Func>) :
    func_pair_(move(rhs.func_pair_)) {
        rhs.release();
    }
 
    scope_exit& operator=(scope_exit&&) = delete;

    ~scope_exit() noexcept {
        if (func_pair_.value) {
            func_pair_.get_base()();
        }
    }

    void release() noexcept { func_pair_.value = false; }
};
 
#ifdef NEFORCE_STANDARD_17
template <typename Func>
scope_exit(Func) -> scope_exit<Func>;
#endif
 

template <typename Func>
class scope_fail {
private:
    compressed_pair<Func, int> func_pair_; 
 
public:
    template <typename F, enable_if_t<!is_same_v<remove_cvref_t<F>, scope_fail> && is_constructible_v<Func, F> &&
                                              !is_nothrow_constructible_v<Func, F>,
                                      int> = 0>
    explicit scope_fail(F&& func) try :
    func_pair_(exact_arg_construct_tag{}, _NEFORCE forward<F>(func), uncaught_exceptions()) {
    } catch (...) {
        func();
    }

    template <typename F, enable_if_t<!is_same_v<remove_cvref_t<F>, scope_fail> && is_constructible_v<Func, F> &&
                                              is_nothrow_constructible_v<Func, F>,
                                      int> = 0>
    explicit scope_fail(F&& func) noexcept :
    func_pair_(exact_arg_construct_tag{}, _NEFORCE forward<F>(func), uncaught_exceptions()) {}
 
    scope_fail(const scope_fail&) = delete;
    scope_fail& operator=(const scope_fail&) = delete;

    scope_fail(scope_fail&& rhs) noexcept :
    func_pair_(move(rhs.func_pair_)) {
        rhs.release();
    }
 
    scope_fail& operator=(scope_fail&&) = delete;

    ~scope_fail() noexcept {
        if (uncaught_exceptions() > func_pair_.value) {
            func_pair_.get_base()();
        }
    }

    void release() noexcept { func_pair_.value = numeric_traits<int>::max(); }
};
 
#ifdef NEFORCE_STANDARD_17
template <typename Func>
scope_fail(Func) -> scope_fail<Func>;
#endif
 

template <typename Func>
class scope_success {
private:
    compressed_pair<Func, int> func_pair_; 
 
public:
    template <typename F, enable_if_t<!is_same_v<remove_cvref_t<F>, scope_success> && is_constructible_v<Func, F> &&
                                              !is_nothrow_constructible_v<Func, F>,
                                      int> = 0>
    explicit scope_success(F&& func) try :
    func_pair_(exact_arg_construct_tag{}, _NEFORCE forward<F>(func), uncaught_exceptions()) {
    } catch (...) {
        func();
    }

    template <typename F, enable_if_t<!is_same_v<remove_cvref_t<F>, scope_success> && is_constructible_v<Func, F> &&
                                              is_nothrow_constructible_v<Func, F>,
                                      int> = 0>
    explicit scope_success(F&& func) noexcept :
    func_pair_(exact_arg_construct_tag{}, _NEFORCE forward<F>(func), uncaught_exceptions()) {}
 
    scope_success(const scope_success&) = delete;
    scope_success& operator=(const scope_success&) = delete;

    scope_success(scope_success&& rhs) noexcept(is_nothrow_move_assignable_v<Func>) :
    func_pair_(move(rhs.func_pair_)) {
        rhs.release();
    }
 
    scope_success& operator=(scope_success&&) = delete;

    ~scope_success() noexcept(is_nothrow_invocable_v<Func>) {
        if (uncaught_exceptions() <= func_pair_.value) {
            func_pair_.get_base()();
        }
    }

    void release() noexcept { func_pair_.value = -numeric_traits<int>::max(); }
};
 
#ifdef NEFORCE_STANDARD_17
template <typename Func>
scope_success(Func) -> scope_success<Func>;
#endif
 // ScopeGuard
 
NEFORCE_END_NAMESPACE__
#endif // NEFORCE_CORE_UTILITY_SCOPE_HPP__