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mergerfs/src/scope_guard.hpp

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// _____ _____ _ _____
// / ____| / ____| | | / ____|_ _
// | (___ ___ ___ _ __ ___ | | __ _ _ __ _ _ __ __| | | | _| |_ _| |_
// \___ \ / __/ _ \| '_ \ / _ \ | | |_ | | | |/ _` | '__/ _` | | | |_ _|_ _|
// ____) | (_| (_) | |_) | __/ | |__| | |_| | (_| | | | (_| | | |____|_| |_|
// |_____/ \___\___/| .__/ \___| \_____|\__,_|\__,_|_| \__,_| \_____|
// | | https://github.com/Neargye/scope_guard
// |_| version 0.9.1
//
// Licensed under the MIT License <http://opensource.org/licenses/MIT>.
// SPDX-License-Identifier: MIT
// Copyright (c) 2018 - 2021 Daniil Goncharov <neargye@gmail.com>.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.
#ifndef NEARGYE_SCOPE_GUARD_HPP
#define NEARGYE_SCOPE_GUARD_HPP
#define SCOPE_GUARD_VERSION_MAJOR 0
#define SCOPE_GUARD_VERSION_MINOR 9
#define SCOPE_GUARD_VERSION_PATCH 1
#include <type_traits>
#if (defined(_MSC_VER) && _MSC_VER >= 1900) || ((defined(__clang__) || defined(__GNUC__)) && __cplusplus >= 201700L)
#include <exception>
#endif
// scope_guard throwable settings:
// SCOPE_GUARD_NO_THROW_CONSTRUCTIBLE requires nothrow constructible action.
// SCOPE_GUARD_MAY_THROW_ACTION action may throw exceptions.
// SCOPE_GUARD_NO_THROW_ACTION requires noexcept action.
// SCOPE_GUARD_SUPPRESS_THROW_ACTION exceptions during action will be suppressed.
// SCOPE_GUARD_CATCH_HANDLER exceptions handler. If SCOPE_GUARD_SUPPRESS_THROW_ACTIONS is not defined, it will do nothing.
#if !defined(SCOPE_GUARD_MAY_THROW_ACTION) && !defined(SCOPE_GUARD_NO_THROW_ACTION) && !defined(SCOPE_GUARD_SUPPRESS_THROW_ACTION)
# define SCOPE_GUARD_MAY_THROW_ACTION
#elif (defined(SCOPE_GUARD_MAY_THROW_ACTION) + defined(SCOPE_GUARD_NO_THROW_ACTION) + defined(SCOPE_GUARD_SUPPRESS_THROW_ACTION)) > 1
# error Only one of SCOPE_GUARD_MAY_THROW_ACTION and SCOPE_GUARD_NO_THROW_ACTION and SCOPE_GUARD_SUPPRESS_THROW_ACTION may be defined.
#endif
#if !defined(SCOPE_GUARD_CATCH_HANDLER)
# define SCOPE_GUARD_CATCH_HANDLER /* Suppress exception.*/
#endif
namespace scope_guard {
namespace detail {
#if defined(SCOPE_GUARD_SUPPRESS_THROW_ACTION) && (defined(__cpp_exceptions) || defined(__EXCEPTIONS) || (_HAS_EXCEPTIONS))
# define NEARGYE_NOEXCEPT(...) noexcept
# define NEARGYE_TRY try {
# define NEARGYE_CATCH } catch (...) { SCOPE_GUARD_CATCH_HANDLER }
#else
# define NEARGYE_NOEXCEPT(...) noexcept(__VA_ARGS__)
# define NEARGYE_TRY
# define NEARGYE_CATCH
#endif
#define NEARGYE_MOV(...) static_cast<typename std::remove_reference<decltype(__VA_ARGS__)>::type&&>(__VA_ARGS__)
#define NEARGYE_FWD(...) static_cast<decltype(__VA_ARGS__)&&>(__VA_ARGS__)
// NEARGYE_NODISCARD encourages the compiler to issue a warning if the return value is discarded.
#if !defined(NEARGYE_NODISCARD)
# if defined(__clang__)
# if (__clang_major__ * 10 + __clang_minor__) >= 39 && __cplusplus >= 201703L
# define NEARGYE_NODISCARD [[nodiscard]]
# else
# define NEARGYE_NODISCARD __attribute__((__warn_unused_result__))
# endif
# elif defined(__GNUC__)
# if __GNUC__ >= 7 && __cplusplus >= 201703L
# define NEARGYE_NODISCARD [[nodiscard]]
# else
# define NEARGYE_NODISCARD __attribute__((__warn_unused_result__))
# endif
# elif defined(_MSC_VER)
# if _MSC_VER >= 1911 && defined(_MSVC_LANG) && _MSVC_LANG >= 201703L
# define NEARGYE_NODISCARD [[nodiscard]]
# elif defined(_Check_return_)
# define NEARGYE_NODISCARD _Check_return_
# else
# define NEARGYE_NODISCARD
# endif
# else
# define NEARGYE_NODISCARD
# endif
#endif
#if defined(_MSC_VER) && _MSC_VER < 1900
inline int uncaught_exceptions() noexcept {
return *(reinterpret_cast<int*>(static_cast<char*>(static_cast<void*>(_getptd())) + (sizeof(void*) == 8 ? 0x100 : 0x90)));
}
#elif (defined(__clang__) || defined(__GNUC__)) && __cplusplus < 201700L
struct __cxa_eh_globals;
extern "C" __cxa_eh_globals* __cxa_get_globals() noexcept;
inline int uncaught_exceptions() noexcept {
return static_cast<int>(*(reinterpret_cast<unsigned int*>(static_cast<char*>(static_cast<void*>(__cxa_get_globals())) + sizeof(void*))));
}
#else
inline int uncaught_exceptions() noexcept {
return std::uncaught_exceptions();
}
#endif
class on_exit_policy {
bool execute_;
public:
explicit on_exit_policy(bool execute) noexcept : execute_{execute} {}
void dismiss() noexcept {
execute_ = false;
}
bool should_execute() const noexcept {
return execute_;
}
};
class on_fail_policy {
int ec_;
public:
explicit on_fail_policy(bool execute) noexcept : ec_{execute ? uncaught_exceptions() : -1} {}
void dismiss() noexcept {
ec_ = -1;
}
bool should_execute() const noexcept {
return ec_ != -1 && ec_ < uncaught_exceptions();
}
};
class on_success_policy {
int ec_;
public:
explicit on_success_policy(bool execute) noexcept : ec_{execute ? uncaught_exceptions() : -1} {}
void dismiss() noexcept {
ec_ = -1;
}
bool should_execute() const noexcept {
return ec_ != -1 && ec_ >= uncaught_exceptions();
}
};
template <typename T, typename = void>
struct is_noarg_returns_void_action
: std::false_type {};
template <typename T>
struct is_noarg_returns_void_action<T, decltype((std::declval<T>())())>
: std::true_type {};
template <typename T, bool = is_noarg_returns_void_action<T>::value>
struct is_nothrow_invocable_action
: std::false_type {};
template <typename T>
struct is_nothrow_invocable_action<T, true>
: std::integral_constant<bool, noexcept((std::declval<T>())())> {};
template <typename F, typename P>
class scope_guard {
using A = typename std::decay<F>::type;
static_assert(is_noarg_returns_void_action<A>::value,
"scope_guard requires no-argument action, that returns void.");
static_assert(std::is_same<P, on_exit_policy>::value || std::is_same<P, on_fail_policy>::value || std::is_same<P, on_success_policy>::value,
"scope_guard requires on_exit_policy, on_fail_policy or on_success_policy.");
#if defined(SCOPE_GUARD_NO_THROW_ACTION)
static_assert(is_nothrow_invocable_action<A>::value,
"scope_guard requires noexcept invocable action.");
#endif
#if defined(SCOPE_GUARD_NO_THROW_CONSTRUCTIBLE)
static_assert(std::is_nothrow_move_constructible<A>::value,
"scope_guard requires nothrow constructible action.");
#endif
P policy_;
A action_;
void* operator new(std::size_t) = delete;
void operator delete(void*) = delete;
public:
scope_guard() = delete;
scope_guard(const scope_guard&) = delete;
scope_guard& operator=(const scope_guard&) = delete;
scope_guard& operator=(scope_guard&&) = delete;
scope_guard(scope_guard&& other) noexcept(std::is_nothrow_move_constructible<A>::value)
: policy_{false},
action_{NEARGYE_MOV(other.action_)} {
policy_ = NEARGYE_MOV(other.policy_);
other.policy_.dismiss();
}
scope_guard(const A& action) = delete;
scope_guard(A& action) = delete;
explicit scope_guard(A&& action) noexcept(std::is_nothrow_move_constructible<A>::value)
: policy_{true},
action_{NEARGYE_MOV(action)} {}
void dismiss() noexcept {
policy_.dismiss();
}
~scope_guard() NEARGYE_NOEXCEPT(is_nothrow_invocable_action<A>::value) {
if (policy_.should_execute()) {
NEARGYE_TRY
action_();
NEARGYE_CATCH
}
}
};
template <typename F>
using scope_exit = scope_guard<F, on_exit_policy>;
template <typename F, typename std::enable_if<is_noarg_returns_void_action<F>::value, int>::type = 0>
NEARGYE_NODISCARD scope_exit<F> make_scope_exit(F&& action) noexcept(noexcept(scope_exit<F>{NEARGYE_FWD(action)})) {
return scope_exit<F>{NEARGYE_FWD(action)};
}
template <typename F>
using scope_fail = scope_guard<F, on_fail_policy>;
template <typename F, typename std::enable_if<is_noarg_returns_void_action<F>::value, int>::type = 0>
NEARGYE_NODISCARD scope_fail<F> make_scope_fail(F&& action) noexcept(noexcept(scope_fail<F>{NEARGYE_FWD(action)})) {
return scope_fail<F>{NEARGYE_FWD(action)};
}
template <typename F>
using scope_success = scope_guard<F, on_success_policy>;
template <typename F, typename std::enable_if<is_noarg_returns_void_action<F>::value, int>::type = 0>
NEARGYE_NODISCARD scope_success<F> make_scope_success(F&& action) noexcept(noexcept(scope_success<F>{NEARGYE_FWD(action)})) {
return scope_success<F>{NEARGYE_FWD(action)};
}
struct scope_exit_tag {};
template <typename F, typename std::enable_if<is_noarg_returns_void_action<F>::value, int>::type = 0>
scope_exit<F> operator<<(scope_exit_tag, F&& action) noexcept(noexcept(scope_exit<F>{NEARGYE_FWD(action)})) {
return scope_exit<F>{NEARGYE_FWD(action)};
}
struct scope_fail_tag {};
template <typename F, typename std::enable_if<is_noarg_returns_void_action<F>::value, int>::type = 0>
scope_fail<F> operator<<(scope_fail_tag, F&& action) noexcept(noexcept(scope_fail<F>{NEARGYE_FWD(action)})) {
return scope_fail<F>{NEARGYE_FWD(action)};
}
struct scope_success_tag {};
template <typename F, typename std::enable_if<is_noarg_returns_void_action<F>::value, int>::type = 0>
scope_success<F> operator<<(scope_success_tag, F&& action) noexcept(noexcept(scope_success<F>{NEARGYE_FWD(action)})) {
return scope_success<F>{NEARGYE_FWD(action)};
}
#undef NEARGYE_MOV
#undef NEARGYE_FWD
#undef NEARGYE_NOEXCEPT
#undef NEARGYE_TRY
#undef NEARGYE_CATCH
#undef NEARGYE_NODISCARD
} // namespace scope_guard::detail
using detail::make_scope_exit;
using detail::make_scope_fail;
using detail::make_scope_success;
} // namespace scope_guard
// NEARGYE_MAYBE_UNUSED suppresses compiler warnings on unused entities, if any.
#if !defined(NEARGYE_MAYBE_UNUSED)
# if defined(__clang__)
# if (__clang_major__ * 10 + __clang_minor__) >= 39 && __cplusplus >= 201703L
# define NEARGYE_MAYBE_UNUSED [[maybe_unused]]
# else
# define NEARGYE_MAYBE_UNUSED __attribute__((__unused__))
# endif
# elif defined(__GNUC__)
# if __GNUC__ >= 7 && __cplusplus >= 201703L
# define NEARGYE_MAYBE_UNUSED [[maybe_unused]]
# else
# define NEARGYE_MAYBE_UNUSED __attribute__((__unused__))
# endif
# elif defined(_MSC_VER)
# if _MSC_VER >= 1911 && defined(_MSVC_LANG) && _MSVC_LANG >= 201703L
# define NEARGYE_MAYBE_UNUSED [[maybe_unused]]
# else
# define NEARGYE_MAYBE_UNUSED __pragma(warning(suppress : 4100 4101 4189))
# endif
# else
# define NEARGYE_MAYBE_UNUSED
# endif
#endif
#if !defined(NEARGYE_STR_CONCAT)
# define NEARGYE_STR_CONCAT_(s1, s2) s1##s2
# define NEARGYE_STR_CONCAT(s1, s2) NEARGYE_STR_CONCAT_(s1, s2)
#endif
#if !defined(NEARGYE_COUNTER)
# if defined(__COUNTER__)
# define NEARGYE_COUNTER __COUNTER__
# elif defined(__LINE__)
# define NEARGYE_COUNTER __LINE__
# endif
#endif
#if defined(SCOPE_GUARD_NO_THROW_ACTION)
# define NEARGYE_MAKE_SCOPE_GUARD_ACTION [&]() noexcept -> void
#else
# define NEARGYE_MAKE_SCOPE_GUARD_ACTION [&]() -> void
#endif
#define NEARGYE_MAKE_SCOPE_EXIT ::scope_guard::detail::scope_exit_tag{} << NEARGYE_MAKE_SCOPE_GUARD_ACTION
#define NEARGYE_MAKE_SCOPE_FAIL ::scope_guard::detail::scope_fail_tag{} << NEARGYE_MAKE_SCOPE_GUARD_ACTION
#define NEARGYE_MAKE_SCOPE_SUCCESS ::scope_guard::detail::scope_success_tag{} << NEARGYE_MAKE_SCOPE_GUARD_ACTION
#define NEARGYE_SCOPE_GUARD_WITH_(g, i) for (int i = 1; i--; g)
#define NEARGYE_SCOPE_GUARD_WITH(g) NEARGYE_SCOPE_GUARD_WITH_(g, NEARGYE_STR_CONCAT(NEARGYE_INTERNAL_OBJECT_, NEARGYE_COUNTER))
// SCOPE_EXIT executing action on scope exit.
#define MAKE_SCOPE_EXIT(name) auto name = NEARGYE_MAKE_SCOPE_EXIT
#define SCOPE_EXIT NEARGYE_MAYBE_UNUSED const MAKE_SCOPE_EXIT(NEARGYE_STR_CONCAT(NEARGYE_SCOPE_EXIT_, NEARGYE_COUNTER))
#define WITH_SCOPE_EXIT(guard) NEARGYE_SCOPE_GUARD_WITH(NEARGYE_MAKE_SCOPE_EXIT{ guard })
// SCOPE_FAIL executing action on scope exit when an exception has been thrown before scope exit.
#define MAKE_SCOPE_FAIL(name) auto name = NEARGYE_MAKE_SCOPE_FAIL
#define SCOPE_FAIL NEARGYE_MAYBE_UNUSED const MAKE_SCOPE_FAIL(NEARGYE_STR_CONCAT(NEARGYE_SCOPE_FAIL_, NEARGYE_COUNTER))
#define WITH_SCOPE_FAIL(guard) NEARGYE_SCOPE_GUARD_WITH(NEARGYE_MAKE_SCOPE_FAIL{ guard })
// SCOPE_SUCCESS executing action on scope exit when no exceptions have been thrown before scope exit.
#define MAKE_SCOPE_SUCCESS(name) auto name = NEARGYE_MAKE_SCOPE_SUCCESS
#define SCOPE_SUCCESS NEARGYE_MAYBE_UNUSED const MAKE_SCOPE_SUCCESS(NEARGYE_STR_CONCAT(NEARGYE_SCOPE_SUCCESS_, NEARGYE_COUNTER))
#define WITH_SCOPE_SUCCESS(guard) NEARGYE_SCOPE_GUARD_WITH(NEARGYE_MAKE_SCOPE_SUCCESS{ guard })
// DEFER executing action on scope exit.
#define MAKE_DEFER(name) MAKE_SCOPE_EXIT(name)
#define DEFER SCOPE_EXIT
#define WITH_DEFER(guard) WITH_SCOPE_EXIT(guard)
#endif // NEARGYE_SCOPE_GUARD_HPP
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